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Aims Chronic right ventricular (RV) pacing may impose ventricular dyssynchrony leading to LV remodelling and is associated with increased morbidity and mortality. Upgrading patients with chronic RV pacing to cardiac resynchronization therapy (CRT) may be considered to restore synchronicity and prevent these deleterious effects. Methods and results A total of 172 patients from two tertiary centres were analysed over a mean follow-up of 21.7 and 23.5 months after primary CRT implantation ( n = 102) and CRT upgrade ( n = 70), respectively. In the latter group, mean duration of RV pacing before CRT upgrade was 80.3 months, and ventricular stimulation was >95%. A significant improvement in left ventricular (LV) ejection fraction (10 and 11% absolute increase in primary CRT vs. upgrades, respectively), LV end-diastolic diameter index (−0.15 cm/m2 vs. −0.2 cm/m2), and LV end-systolic diameter (−6.0 vs. −7.0 mm) was observed in both groups, which did not differ between primary CRT recipients and CRT upgrades. Response to CRT upgrade was independent of the underlying rhythm, QRS duration, duration of prior RV pacing, or LV function and size at baseline. Of note, even seven of nine patients with RV pacing >12 years responded favourably to CRT. Conclusion The current study demonstrates that CRT reverses LV remodelling in heart failure patients with chronic RV pacing in a similar way as in primary CRT recipients, even after very long periods of RV pacing. Our data, therefore, may have important implications for the treatment of pacemaker-dependent patients with heart failure, and support the use of CRT in this setting.

Background: Few studies have assessed the long-term effects of cardiac resynchronization therapy (CRT) in patients with advanced heart failure (HF) and previously right ventricular apical pacing (RVAP). Aims: To assess the clinical and hemodynamic impact of upgrading to biventricular pacing in patients with severe HF and permanent RVAP in comparison with patients who had CRT implantation as initial therapy. Methods and Results: Thirty-nine patients with RVAP, advanced HF (New York Heart Association [NYHA] III–IV), and severe depression of left ventricular ejection fraction (LVEF) were upgraded to biventricular pacing (group A). Mean duration of RVAP before upgrading was 41.8 ± 13.3 months. Clinical and echocardiographic results were compared to those obtained in a group of 43 patients with left bundle branch block and similar clinical characteristics undergoing “primary” CRT (group B). Mean follow-up was 35 ± 10 months in patients of group A and 38 ± 12 months in group B. NYHA class significantly improved in groups A and B. LVEF increased from 0.23 ± 0.07 to 0.36 ± 0.09 (P < 0.001) and from 0.26 ± 0.02 to 0.34 ± 0.10 (P < 0.001), respectively. Hospitalizations were reduced by 81% and 77% (P < 0.001). Similar improvements in echocardiographic signs of ventricular desynchronization were also observed. Conclusion: Patients upgraded to CRT exhibit long-term clinical and hemodynamic benefits that are similar to those observed in patients treated with CRT as initial strategy. (PACE 2010; 841–849)

This study demonstrates the capabilities of MRI in the assessment of cardiac pacing induced ventricular dyssynchrony, and the findings support the need for employing more physiological pacing. A human donor heart deemed non-viable for transplantation, was reanimated using an MR compatible, four-chamber working perfusion system. The heart was imaged using a 1.5T MR scanner while being paced from the right ventricular apex (RVA) via an epicardial placed lead. Four-chamber, short-axis, and tagged short-axis cines were acquired in order to track wall motion and intramyocardial strain during pacing. The results of this study revealed that the activation patterns of the left ventricle (LV) during RVA pacing demonstrated intraventricular dyssynchrony; as the left ventricular mechanical activation proceeded from the septum and anterior wall to the lateral wall, with the posterior wall being activated last. As such, the time difference to peak contraction between the septum and lateral wall was approximately 125 msec. Likewise, interventricular dyssynchrony was demonstrated from the four-chamber cine as the time difference between the peak LV and RV free wall motion was 180 msec. With the ongoing development of MR safe and MR compatible pacing systems, we can expect MRI to be added to the list of imaging modalities used to optimize cardiac resynchronization therapy (CRT) and/or alternate site pacing.

Objective The study objective was to compare the left ventricular (LV) dyssynchrony and torsional behavior between right ventricular apical (RVA) and right ventricular septal (RVS) pacing. Methods Forty-six patients with symptomatic sick sinus syndrome and preserved LV function were assigned to 2 groups: RVA (n = 23) and RVS (n = 23). Echocardiographic study including two-dimensional speckle tracking imaging was performed in the AAI and DDD modes. Results Mean QRS width during DDD mode was significantly longer with RVA pacing than with RVS pacing. Dyssynchrony, torsion, and untwisting rate during DDD mode were significantly worse with RVA than with RVS pacing. In patients with RVA pacing, there was an increase in longitudinal dyssynchrony from AAI to DDD mode that significantly correlated with the deterioration of untwisting rate. Conclusion In bradyarrhythmic patients with preserved LV function, RVS pacing resulted in a reduced LV dyssynchrony and better torsional behavior than RVA pacing.

Background Functional mitral regurgitation (FMR) is a frequent condition in the setting of dilated cardiomyopathy (DCM) and its physiopathological mechanisms are complex. The aim of this study was to determine the influence of left ventricular remodeling and mechanical dyssynchrony on the occurrence of FMR in non-ischemic DCM. Methods Prospective study involving 52 patients (mean age = 57 ± 10 years, sex ratio = 1.8) with non ischemic dilated cardiomyopathy. Two groups were compared: the group with FMR (group MR+ = 31 patients) and that without FMR (group MR− = 21 patients). Results Mean QRS duration was 141 ± 29 ms and 63% of patients had complete left bundle branch block (LBBB), with no significant difference between the 2 groups. The echocardiographic parameters representing left ventricular systolic function were similar in the 2 groups except for cardiac output which was lower in the group MR+ (3.3 ± 1 L/min vs 4 ± 1.3 L/min; P = 0.02). For mitral deformation indices, tenting area (3.6 ± 1 cm2 vs 2.5 ± 0.8 cm2; P = 0.005) and tenting height (1.5 ± 0.3 cm vs 1 ± 0.2 cm; P Conclusion This study showed that only the mitral deformation indices were well correlated to both the presence and the severity of FMR. Left ventricular remodeling indices were not good determinants of FMT. However, the intra ventricular dyssynchrony indices were associated to the presence of FMR and not to its severity.

Cil: V prospektivni studii stanovit pocet responderů a non-responderů na srdecni resynchronizacni lecbu (SRL), definovat rozdily mezi respondery a non-respondery a zhodnotit vývoj klinickeho a hemodynamickeho ucinku SRL u responderů v zavislosti na době od implantace (3 a 15 měsiců po implantaci).Soubor pacientů a metodika: Do sledovani bylo zařazeno 58 pacientů, jimž byl v obdobi od cervence 2005 do května 2008 implantovan biventrikularni system. Pacienti byli průměrneho věku 67 ± 9 let, se srdecni insuficienci NYHA IV (jeden pacient), NYHA III-IV (18 pacientů), NYHA III (23 pacientů), NYHA II-III (13 pacientů), NYHA II (tři pacienti), průměrnou siři QRS komplexu 193 ± 33 ms a s diagnozou dilatacni kardiomyopatie (DKMP) (22 pacientů), s ischemickou chorobou srdecni (ICHS) (33 pacientů), koincidenci obojiho (tři pacienti). Jeden den před implantaci a tři a 15 měsiců od implantace byly hodnoceny: třida NYHA, kvalita života (QOL) dle skore Minnesotskeho dotazniku kvality života, sestiminutový test chůze (6MWT). Kromě standardniho echokardiografickeho vysetřeni jsme hodnotili přitomnost interventrikularni a intraventrikularni dyssynchronie. K neinvazivnimu odhadu tepoveho výdeje byl měřen velocity time integral (VTI) průtoku ve výtokovem traktu leve komory (LVOT), kontraktilita leve komory byla hodnocena parametrem dP/dt (velikost intraventrikularniho tlakoveho přirůstku). Za respondera byl oznacen každý pacient, u něhož doslo po 15 měsicich k soucasnemu zlepseni kvality života, třidy NYHA anebo prodlouženi vzdalenosti při sestiminutovem testu chůze o vice než 10 %.Výsledky: Po 15 měsicich bylo oznaceno za respondery na SRL 38 nemocných (66 %) a za non-respondery 19 pacientů (33 %). Při porovnani výchozich parametrů (tj. před implantaci biventrikularniho systemu) mezi respondery a non-respondery bylo zjistěno, že tyto dvě skupiny se statisticky významně lisily pouze v zavažnosti komorove dyssynchronie - u responderů byly přitomny statisticky zavažnějsi znamky interventrikularni dyssynchronie (interventrikularni mechanicke zpožděni [IVMD] cinilo u responderů 62,1 ± 23,1 ms vs. u non-responderů 46,8 ± 30,3 ms, p < 0,05) - a zavažnosti intraventrikularni dyssynchronie (větsi zpožděni vrcholů kontrakce bazalnich segmentů septa a lateralni stěny [Ts-lateral-septal] u responderů 71,2 ± 32,0 ms vs. u non-responderů 48,4 ± 29,2 ms, p < 0,05). Ve skupině responderů bylo dale zjistěno, že ke statisticky významnemu zlepseni vsech sledovaných parametrů (klinických i echokardiografických) doslo již po třech měsicich. V průběhu dalsiho sledovani (mezi 3. a 15. měsicem od implantace) doslo k významne změně již pouze u tři echokardiografických parametrů (vzestup ejekcni frakce leve komory [EF LK] z 27,1 ± 9,8 % na 32,8 ± 12,5 % [p < 0,001], zmenseni end-diastolickeho rozměru (EDD) leve komory z 66,1 ± 8,3 mm na 64,0 ± 8,1 mm [p < 0,05] a zvětseni VTI průtoku v LVOT z 16,7 ± 4,1 cm na 18,8 ± 4,4 cm [p < 0,001]). U klinických parametrů a ostatnich echokardiografických parametrů jsme dalsi významne změny nepozorovali.Zavěr: Výsledky ziskane v nasem souboru prokazuji podobný pocet responderů a non-responderů (66 % vs. 33 %), jaký je uvaděn v literatuře. Při porovnani vsech výchozich klinických a echokardiografických parametrů se tyto dvě skupiny statisticky významně lisily pouze v zavažnosti komorove dyssynchronie. Dalsim nasim zjistěnim je fakt, že ve skupině responderů doslo ke statisticky významnemu zlepseni vsech sledovaných parametrů (klinických i echokardiografických) již po třech měsicich srdecni resynchronizacni lecby.

INTRODUCTION The combination of pulsed wave (PW) and tissue Doppler imaging (TDI) has been proposed as a new method to assess left ventricular (LV) mechanical dyssynchrony (LVMD), but results have not been validated. We investigated the correlation of a combination of PW and TDI with a positive response to cardiac resynchronization therapy (CRT). MATERIAL AND METHODS We studied 108 consecutive patients who received CRT. Patients with atrial fibrillation were excluded. The time difference (T(PW-TDI)) between onset of QRS to the end of LV ejection by PW (T(PW)) and onset of QRS to the end of the systolic wave in LV basal segments with greatest delay by TDI (T(TDI)) was measured before CRT and during short-term and long-term follow-up. RESULTS The T(PW-TDI) interval before CRT was 74 ±48 ms. Intra-observer variabilities for T(PW) and T(TDI) were 1.5 ±0.24% and 1 ±0.17%. Inter-observer variabilities for T(PW) and T(TDI) were 1 ±0.36% and 1 ±0.64%, respectively. T(PW-TDI) > 50 ms was defined as the cutoff value for diagnosis of LVMD by receiver operating curve (ROC) analysis. During follow-up of 15 ±11 months, the sensitivity and specificity of TP(PW-TDI) to predict a positive response to CRT were 98% and 82%, respectively. The area under the ROC curve was 0.92. There was a significant agreement between LVMD determined by T(PW-TDI) and the positive response to CRT (κ=0.80). CONCLUSIONS Left vertricular dyssynchrony detected by the method combining PW and TDI demonstrated a high reproducibility, sensitivity, specificity and agreement with a positive response to CRT.

Current selection guideline for CRT uses broad QRS duration (>120 ms) as a marker for ventricular dyssynchrony. However, more recent data supports mechanical marker specifically measured by Tissue Doppler Imaging (TDI) as a better criterion to predict response to CRT. Sixty seven patients with significant left ventricular dysfunction (EF less than 40%) and narrow QRS complex were prospectively enrolled. They underwent Tissue Doppler Imaging (TDI) study to evaluate intraventricular mechanical dyssynchrony. Dyssynchrony index which is defined as standard deviation of time to peak systolic velocity in twelve ventricular segments was measured. A value greater than 32.6 is taken to reflect significant ventricular dyssynchrony. Overall 38 patients (56.7%) demonstrated significant dyssynchrony. There was no significant correlation between QRS duration and the Ts-SD-12 (r = 0.14, p = 0.11). Ventricular mechanical dyssynchrony is common in patients with normal QRS duration. Therefore, QRS duration alone will miss a substantial proportion of suitable patients for CRT and therefore deny them this adjunct therapy. We propose echocardiographic parameters, specifically TDI, to be included in patient selection criteria for CRT. (JUMMEC 2009; 12(2): 57-62)

BACKGROUND: In healthy people the left ventricle presents a counter-clockwise apical rotation and a clockwise basal rotation ending in late systole. In early systole (during isovolumic contraction) there is a fast and inverse rotation (counter-clockwise at the base and clockwise at the apex). This opposite rotation between apex and base produces the systolic torsion of the left ventricle. The effect of permanent conventional pacing on this torsion is little known. OBJECTIVES: The aim of this study was to assess, by speckle tracking echocardiography, left ventricular rotation and torsion in patients conventionally paced at the apex of the right ventricle. METHODS: Left ventricular apical and basal rotation and the consequent torsion were evaluated by means of speckle tracking echocardiography, in 13 paced patients, without ischemic or valvular disease, and in 17 healthy participants. Left ventricular dyssynchrony was evaluated by means of temporal uniformity of strain. RESULTS: In the paced group there was a significant reduction in early-systolic clockwise torsion (-0.4 degrees +/- 1.2 vs. -1.5 degrees +/- 1.6; P = 0.04), and in late-systolic counter-clockwise torsion (15.1 degrees +/- 4.3 vs. 19.1 degrees +/- 5.5; P = 0.03). Circumferential temporal uniformity of strain averaged significantly lower in paced patients. CONCLUSIONS: Conventional pacing from the apex of the right ventricle alters both the torsional mechanic and the synchrony of the left ventricle.

Background Prolonged QRS duration (QRS) has been associated with left ventricular dyssynchrony and dysfunction and with the development of heart failure. However, whether persistence or development of increased QRS over time is associated with an increased incidence of heart failure in hypertensive patients, independent of blood pressure lowering and regression of electrocardiographic left ventricular hypertrophy (LVH) has not been examined. Methods and results The relation of QRS over time to incident heart failure was examined in 8945 hypertensive patients without history of heart failure who were randomly assigned to losartan-based or atenolol-based treatment. During 4.7 +/- 1.1 years follow-up, heart failure hospitalization occurred in 282 patients (3.2%): in 157 with in-treatment QRS less than 110 ms (4.6 per 1000 patient-years) and in 125 with persistence or development of QRS 110 ms or more (13.4 per 1000 patient-years). In univariate Cox analyses in which QRS during the study was entered as a time-varying covariate, in-treatment persistence or development of a QRS 110 ms or more was associated with a 153% increased risk of developing heart failure [hazard ratio 2.53, 95% confidence interval (CI) 2.00-3.20]. After adjusting for treatment, baseline risk factors for heart failure, incident myocardial infarction and for baseline and in-treatment electrocardiographic LVH and blood pressure, persistence or development of a QRS 110 ms or more remained associated with a 102% increased risk of new-onset heart failure (hazard ratio 2.02, 95% CI 1.49-2.74). Conclusion Persistence or development of a prolonged QRS during antihypertensive therapy is associated with an increased likelihood of new-onset heart failure, independent of blood pressure lowering, treatment modality and regression of electrocardiographic LVH in patients with essential hypertension. These findings suggest that serial assessment of QRS over time can be used to track the risk of heart failure in hypertensive patients.

It has been firmly established that cardiac resynchronization therapy (CRT) reduces symptoms and improves mortality in patients with moderate-to-severe chronic heart failure [New York Heart Association (NYHA) class III-IV], despite optimal heart failure medication and with wide QRS complex on the surface electrocardiogram as evidence of ventricular dyssynchrony, but not whether such treatment is efficacious in mildly symptomatic heart failure patients. In such patients, the treatment goal is to prevent disease progression rather than to improve symptoms. The REVERSE trial was the first randomized, controlled study of CRT in NYHA I-II patients. Cardiac resynchronization therapy in this study induced substantial reverse remodelling over 12-18-24 months of follow-up and was linked to a significant delay in the time to first heart failure hospitalization and eventually in the time to the combined endpoint of time to first heart failure hospitalization or death. The MADIT CRT designed as a morbidity-mortality study corroborated these findings with a significant reduction in heart failure events and significant reverse remodelling. These findings most likely will translate into a wider use of CRT in mildly symptomatic patients to prevent disease progression.

Left ventricular (LV) dyssynchrony after reperfusion therapy has been closely examined as a cause of chronic remodeling, but the details have not been clarified. The present study measured LV dyssynchrony appearing immediately after reperfusion therapy using real-time three-dimensional echocardiography (RT-3DE), and assessed the significance of this phenomenon in relation to dual single photon emission computed tomography (SPECT) of (123)iodine beta methyliodophenyl pentadecanoic acid ((123)I-BMIPP) and (201)thallium ((201)Tl).Subjects comprised 58 patients with first-time acute myocardial infarction who received reperfusion therapy and underwent RT-3DE and dual SPECT of (123)I-BMIPP and (201)Tl within two weeks of onset. Two dyssynchrony parameters were measured using RT-3DE in the acute phase and six months later. After evaluating the correlation of these dyssynchrony parameters to resting (201)Tl uptake, (201)Tl washout, (123)I-BMIPP uptake, and (201)Tl-(123)I-BMIPP discrepancy (Tl-BMIPP discrepancy), we compared scintigraphic parameters in the chronic phase between groups with improved dyssynchrony and those without.Acute dyssynchrony exhibited a significant positive correlation to Tl-BMIPP discrepancy and it was significantly increased in the group with improved dyssynchrony in the chronic phase, revealing close relationship between dyssynchrony and Tl-BMIPP discrepancy. Then the subjects were divided into positive Tl-BMIPP discrepancy and negative discrepancy groups, and the parameters of cardiac function were compared between them. In the chronic phase, improved cardiac function was observed in the group with positive Tl-BMIPP discrepancy compared to negative discrepancy.LV dyssynchrony after reperfusion therapy correlates positively with Tl-BMIPP discrepancy, reflecting acute myocardial stunning, in which ventricular contraction improves during the chronic phase.

The main reasons for lack of response in patients undergoing cardiac resynchronization therapy are imperfect selection techniques, procedure-related conditions, and pacemaker adjustment during follow-up. The main limitation of the echocardiographic techniques used for patient selection is the inter-measurement variability in the determination of the time of regional mechanical activation. Two-dimensional (2D) speckle tracking echocardiography (STE) is a more robust tool than tissue Doppler techniques because of its angle-independency. Although the ability of 2D-STE to quantify left ventricular (LV) dyssynchrony has been demonstrated, its accuracy depends on image quality. Another important limitation is the potential loss of speckles due to motion out of the imaging plane, which can be overcome by the recently developed three-dimensional (3D) STE. Because of its inherent 3D nature, this new technique is likely to better reflect both magnitude and timing of regional LV function, and therefore presents an opportunity for more accurate quantification of LV dyssynchrony.

There are currently limited data on the relationships between resting perfusion abnormalities, left ventricular ejection fraction (LVEF), New York Heart Association (NYHA) functional class, and exercise capacity as defined by peak VO(2) and 6-minute walk test in patients with heart failure (HF) and reduced LVEF. Furthermore, the association between resting perfusion abnormalities and left ventricular dyssynchrony is currently unknown. This article addresses the Heart Failure and A Controlled Trial Investigating Outcomes of Exercise TraiNing (HF-ACTION) gated SPECT imaging (gSPECT) substudy baseline results.HF-ACTION was a multicenter, randomized controlled trial of aerobic exercise training versus usual care in 2,331 stable patients with LVEF ofor = 35% and NYHA class II to IV HF symptoms treated with optimal medical therapy. Subjects enrolled in the HF-ACTION substudy underwent resting Tc-99m tetrofosmin gSPECT at baseline (n = 240). Images were evaluated for extent and severity of perfusion abnormalities using a 17-segment and a 5-degree gradation severity score (summed rest score [SRS]). Left ventricular function and dyssynchrony were assessed using validated available commercial software.The average age of patients enrolled was 59, 69% were male, 63% were white, and 33% were African American. Of the 240 participants, 129 (54%) were ischemic and 111 (46%) were nonischemic in etiology. The median LVEF by gSPECT for the entire cohort was 26%. Among the nuclear variables, there was a modest correlation between LVEF and SRS (r = -0.31, P.0001) and there were stronger correlations between phase SD and SRS (r = 0.66, P.0001) as well as phase SD and LVEF (r = -0.50, P.0001). Patients with NYHA class III symptoms had more severe and significant degrees of dyssynchrony (median phase SD 54 degrees ) than those with NYHA class II symptoms (median phase SD 39 degrees, P = .001). Patients with an ischemic etiology had a higher SRS (P.0001) and significantly more dyssynchrony (P.0001) than those who were nonischemic. However, there was no difference in LVEF or objective measures of exercise capacity between these groups. With respect to peak VO(2), there was a weak correlation with LVEF (r = 0.18, P = .006) and no correlation with SRS (r = -0.04, P = 0.59) or with dyssynchrony (r = -0.13, P = .09). A weak but statistically significant correlation between SRS and 6-minute walk was observed (r = -0.15, P = .047).Gated SPECT imaging can provide important information in patients with HF due to severe LV dysfunction including quantitative measures of global systolic function, perfusion, and dyssynchrony. These measurements are modestly but significantly related to symptom severity and objective measures of exercise capacity.

Fragmented QRS complexes in the electrocardiograms (ECGs) of patients with coronary artery disease are associated with adverse cardiac events. However, there are limited data on its predictive usefulness in patients with nonischemic dilated cardiomyopathy. Left ventricular dyssynchrony is common in heart failure patients who have wide QRS intervals, but its frequency in patients with narrow QRS intervals is uncertain.To investigate the relationship between fragmented QRS complexes and intraventricular dyssynchrony in patients with nonischemic dilated cardiomyopathy in sinus rhythm.Sixty nonischemic dilated cardiomyopathy patients with sinus rhythm and narrow QRS intervals were recruited. Forty patients had a fragmented QRS in their basal ECG, and 20 patients did not have a fragmented QRS. Patients were analyzed for correlation between fragmented QRS complexes and intraventricular dyssynchrony.The maximal difference in time to the peak myocardial systolic velocity between any two left ventricular segments (Max-ASE Sys), and maximal difference between Max-ASE Sys and the mean value of all segments (Max-ASE to Mean Sys) were significantly higher in patients with fragmented QRS complexes (P=0.001 and P=0.003, respectively). Seventy-two per cent of the patients with fragmented QRS complexes had significant left ventricular dyssynchrony; 15% of patients without fragmented QRS complexes had significant left ventricular dyssynchrony (P0.0001). The presence of fragmented QRS complexes in leads corresponding to the specific ventricular segment in basal ECG was found to detect intraventricular dyssynchrony with 90.6% sensitivity (negative predictive value of 85%).Fragmentation in the resting ECG is associated with significant intraventricular dyssynchrony in patients with nonischemic cardiomyopathy, narrow QRS and sinus rhythm. Fragmentation in ECG might be useful in identifying patients who could benefit from cardiac resynchronization therapy.

The aim of this study was to determine the effect of long-term right ventricular pacing on left ventricular (LV) mechanical dyssynchrony in children and young adults with congenital and acquired heart block. Eighteen patients aged 19 +/- 7 years with congenital heart block (group I), 9 aged 21 +/- 11 years with acquired heart block after congenital heart surgery (group II), and 15 healthy control subjects (group III) were studied. The LV volumes, ejection fractions, and systolic dyssynchrony index (SDI) values, as determined using 3-dimensional echocardiography, were compared among groups. Groups I (6.68 +/- 2.44%) and II (9.43 +/- 4.44%) had significantly greater SDI values than group III (3.88 +/- 0.63%) (p = 0.011 and p0.001, respectively). The prevalence of LV mechanical dyssynchrony (SDI5.14%, mean + 2 SDs of controls) in groups I and II was 72% and 67%, respectively. In 27 patients with right ventricular pacing, LV SDI values were correlated negatively with the LV ejection fractions (r = -0.74, p0.001). The times to minimum regional volume were significantly longer in lateral, posterior, and inferior segments in group I and septal and inferior segments in group II compared to those in group III (p0.05). Compared to patients without LV dyssynchrony, patients with LV dyssynchrony had lower LV ejection fractions (p0.001), had shorter RR intervals (p0.001), and tended to have dual-chamber pacing (p = 0.088) but had similar durations of pacing, QRS durations, and positions of pacing wires (epicardial vs endocardial). In conclusion, permanent right ventricular pacing in childhood has a negative effect on LV systolic function through the induction of mechanical dyssynchrony, the magnitude and pattern of which differ between congenital and acquired heart block.

Heart failure is a chronic progressive syndrome, which impairs quality of life and is associated with frequent hospitalizations and a high mortality rate despite optimal medical therapy. Ventricular dyssynchrony is characteristic of systolic heart failure in some of the patients and is recognized as an interventricular conduction abnormality on the ECG, commonly in the form of left bundle branch block. This contributes to abnormal ventricular contraction pattern, which further reduces cardiac output and exacerbates symptoms. Data from clinical trials have demonstrated that by pacing the right and left ventricle simultaneously, as in cardiac resynchronization therapy, ventricular contraction improves with a resultant reduction in symptoms and an improvement in cardiac output and quality of life in the majority of patients. This article provides an overview of ventricular dyssynchrony and the effect cardiac resynchronization therapy has on ventricular function and on quality of life and symptoms.

Ventricular dyssynchrony plays a central role in the expression and progression of heart failure (HF). An independent risk factor for cardiac mortality, ventricular dyssynchrony is characterized by delay in left ventricular (LV) lateral wall contraction. This leads to decreased pumping efficiency, with resulting fluid retention and impaired exercise tolerance. Cardiac resynchronization therapy (CRT) attempts to improve cardiac efficiency by restoring the normal mechanical relationship between right and left ventricular contraction. Cardiac output increases with resynchronization, while ventricular filling pressure decreases without increasing cardiac oxygen consumption. Cardiac resynchronization therapy can also reverse LV dysfunction and reduce mitral regurgitation in patients with HF. Since 1999, the efficacy of implantable CRT devices has been evaluated in clinical trials enrolling more than 4,000 patients with heart disease. In the CARE-HF trial, CRT reduced the risk of death by 36% relative to standard pharmacologic therapy. Combining CRT with a defibrillator might produce an added benefit. In the COMPANION trial, all-cause mortality in patients randomized to a CRT-defibrillator combination was less than in patients receiving CRT therapy alone. Cardiac resynchronization therapy has also been found to decrease morbidity and improve functional status and quality of life. At the present time, the indications for CRT are limited and include symptomatic HF despite optimal medical therapy, prolonged QRS interval, and LVEF < or = 35%. However, indications for CRT are still evolving and may be expanded as further studies identify those most likely to benefit.

The purpose of this study is to assess the incremental value of tissue Doppler (TDI) derived displacement curves (TDint) compared to TDI velocity curves (TDvel) for the evaluation of left ventricular (LV) dyssynchrony (LVD). About 25 patients (pts.) with systolic heart failure were studied by TDvel and TDint. Four TDI sample volumes were placed at the basal and four at the mid ventricular myocardium, utilising two imaging planes. LV dyssynchrony (LVD) was defined as an interregional delay of >40 ms corrected for heart rate. 10 pts. had synchronous contraction, 15 pts. LVD as defined by two experts (EC). To determine diagnostic accuracy and intra-observer variability two identical sets of 100 documents (25 pts. × two imaging planes × two modalities) were produced and presented in random order to one trained (TR) and two untrained (UR) readers. The TR more frequently classified documents as unreadable (7.5 vs. 3.5%, P < 0.05) but more often as correct, i.e., consistent with EC (72.0 vs. 57.8%, P < 0.001). 8.7% of the documents were classified as unreadable using TDvel, 1.0% when applying TDint (P < 0.001). The mean value of correct classification of all 3 readers was 54.3% (TDvel only), 70.7% (TDint only), and 77.7% (combining both modalities), (P < 0.001). The kappa value for TR and TDint was 0.68, for TDvel 0.29. For UR, kappa did not differ (TDint: 0.58; TDvel 0.51). TDint is superior to TDvel in accuracy, reproducibility, and applicability for skilled and unskilled investigators when evaluating LVD by TDI. The combined application of TDint and TDvel is optimal.

Background: Responders to cardiac resynchronization therapy (CRT) have greater left ventricular (LV) dyssynchrony than nonresponders prior to CRT. Aim: We conducted this study to see whether the long term responders have more worsening of LV dyssynchrony and LV function on acute interruption of CRT. Materials and Methods: We identified 22 responders and 13 nonresponders who received CRT as per standard criteria for 23.73 ± 7.9 months (median 24.5 months). We assessed the acute change in LV function, mitral regurgitation (MR) and compared LV dyssynchrony in CRT on and off modes. Results: On turning off CRT, there was no significant worsening of LV dyssynchrony in both responders and nonresponders. The dyssynchrony measurements by SPWMD, TDI and 3D echocardiography did not correlate significantly. LVESV increased (p = 0.02) and MR (p = 0.01) worsened in CRT-off mode in responders only without significant change in LVEF or LV dimensions. Discussion and Conclusion: In long-term responders to CRT, there is alteration in the function of remodeled LV with acute interruption of CRT, without significant worsening of LV dyssynchrony. The role of different echocardiographic parameters in the assessment of LV dyssynchrony remains controversial. Even after long-term CRT reversely remodels the LV, the therapy needs to be continued uninterrupted for sustained benefits.

Cardiac pacing is the only effective treatment for patients with sick sinus syndrome and atrioventricular conduction disorders. In cardiac pacing, the endocardial pacing lead is typically positioned at the right ventricular (RV) apex. At the same time, there is increasing indirect evidence, derived from large pacing mode selection trials and observational studies, that conventional RV apical pacing may have detrimental effects on cardiac structure and left ventricular function, which are associated with the development of heart failure. These detrimental effects may be related to the abnormal electrical and mechanical activation pattern of the ventricles (or ventricular dyssynchrony) caused by RV apical pacing. Still, it remains uncertain if the deterioration of left ventricular function as noted in a proportion of patients receiving RV apical pacing is directly related to acutely induced left ventricular dyssynchrony. The upgrade from RV pacing to cardiac resynchronization therapy may partially reverse the deleterious effects of RV pacing. It has even been suggested that selected patients with a conventional pacemaker indication should receive cardiac resynchronization therapy to avoid the deleterious effects. This review will provide a contemporary overview of the available evidence on the detrimental effects of RV apical pacing. Furthermore, the available alternatives for patients with a standard pacemaker indication will be discussed. In particular, the role of cardiac resynchronization therapy and alternative RV pacing sites in these patients will be reviewed.

Background Since the introduction of cardiac resynchronization therapy, the assessment of left ventricular (LV) dyssynchrony has become increasingly important. Real-time three-dimensional echocardiography (RT-3DE) is one of the methods that is increasingly used. However, normal reference data in a young population are scarce. Methods RT-3DE was performed in 73 healthy adolescents aged 12 to 18 years. A systolic dyssynchrony index was derived from the dispersion of time to minimum regional volume for all 16 LV segments. Results Acquisition of RT-3DE data sets was feasible in 67 of 73 subjects (92%). LV end-diastolic volume and LV end-systolic volume were 99 ± 25 and 41 ± 15 mL, respectively. All controls had highly synchronized segmental function (systolic dyssynchrony index, 1.26 ± 0.53%). Dyssynchrony was independent of age, weight, or length. Interobserver variability for the dyssynchrony index was 2 ± 2 ms and 0.3 ± 0.2% for the absolute and heart rate–corrected values, respectively. Intraobserver variability was 2.0 ± 0.07 ms and 0.0 ± 0.27%, respectively. Conclusions RT-3DE could be performed in most healthy adolescents with good interobserver and intraobserver variability. Highly synchronized segmental function was present and was independent of age, weight, or length.

Right ventricular (RV) apical pacing induces dyssynchrony by a left bundle branch block type electrical activation sequence in the heart and may impair left ventricular (LV) function. Whether these functional changes are accompanied by changes in myocardial perfusion, oxidative metabolism and efficiency, and the relation with the induction of LV dyssynchrony are unknown. Our study was designed to investigate the acute effects of RV pacing on these parameters. Ten patients with normal LV ejection fraction and VVI/DDD pacemaker were studied during AAI pacing/sinus rhythm without RV pacing (pacing-OFF) and with RV pacing (pacing-ON) at the same heart rate. Dynamic [15O]water and [11C]acetate positron emission tomography was used to measure perfusion and oxidative metabolism (kmono) of the LV. An echocardiographic examination was used to assess LV stroke volume (SV) and LV dyssynchrony. Myocardial efficiency of forward work was calculated as systolic blood pressure × cardiac output/LV mass/kmono. RV pacing decreased SV in all subjects (mean decrease 13%, from 76 ± 7 to 66 ± 7 ml, p = 0.004), but global perfusion and kmono were unchanged. The efficiency tended to be lower with pacing-ON (70 ± 20 vs 81 ± 21 mmHg l/g, p = 0.066). In patients with dyssynchrony during pacing (n = 6) efficiency decreased by 23% (from 78 ± 25 to 60 ± 14 mmHg l/g, p = 0.02), but in patients without dyssynchrony no change in efficiency was detected. Accordingly, heterogeneity in myocardial perfusion and oxidative metabolism was detected during pacing in patients with dyssynchrony but not in those without dyssynchrony. RV pacing resulted in a significant decrease in SV. However, deleterious effects on LV oxidative metabolism and efficiency were observed only in patients with dyssynchrony during RV pacing.

Background: Preimplantation left ventricular dyssynchrony is considered a prerequisite for a beneficial response to cardiac resynchronization therapy (CRT). However, electrical dyssynchrony estimated by QRS duration (QRSd) on ECG has not been proven to be an optimal surrogate of mechanical dyssynchrony. We evaluated the correlation of mechanical dyssynchrony with QRSd as measured by signal-averaged electrocardiography (SAECG) in comparison with measurements based on conventional surface ECG and with onscreen measurements based on digital ECG. Methods: We included 49 consecutive patients with decompensated heart failure (40 men, aged 66.8 ± 9.5 years), New York Heart Association (NYHA) class II–IV, and LVEF ≤ 40%. QRSd was calculated by manual measurement of 12-lead ECG, on-screen measurement of computer-based ECG, and calculation of total ventricular activation time on SAECG. Results: Only 60.4% of the studied patients had QRS ≥ 120 ms based on measurements derived by SAECG compared to 69.4% by using on-screen measurement of computer-based ECG and 73.5% based on surface ECG (P = 0.041). Interventricular but not intraventricular delay was correlated with QRSd. The correlation of interventricular dyssynchrony with QRSd was stronger when measured by SAECG than by surface ECG (r = 0.45, P = 0.001 vs r = 0.35, P < 0.01). Among patients with ischemic cardiomyopathy, no significant correlation was demonstrated between mechanical dyssynchrony and QRSd. In nonischemic patients, interventricular delay was significantly correlated with QRSd measured by surface ECG (r = 0.45, P < 0.05) and SAECG (r = 0.46, P < 0.05). Conclusions: The use of SAECG results in different patient classification in wide QRS complex category as compared to surface ECG. Furthermore, QRSd measured by SAECG is correlated with interventricular but not intraventricular dyssynchrony in heart failure patients.

Objectives This study sought to establish normal values for real-time 3-dimensional echocardiography (RT3DE)–derived left ventricular (LV) dyssynchrony index (LVDI) and determine its age dependency, and to compare dyssynchrony in patients with normal LV function and patients with dilated cardiomyopathy (DCM), with and without left bundle branch block (LBBB). Background Cardiac resynchronization therapy is known to be ineffective in one-third of patients with heart failure, highlighting the need for alternative techniques to assess LV dyssynchrony. Methods Datasets from RT3DE were analyzed to calculate LVDI using 16- and 17-segment models. First, 135 normal subjects were studied to establish LVDI abnormality threshold (mean + 2 SD) and to study the relationship with age. Then, 3 groups of patients (N = 16 each: DCM with and without LBBB, normal LV function with LBBB) were compared with 50 age-matched normal control subjects. Results In normal subjects, the 16-segment model resulted in a lower LVDI abnormality threshold than the 17-segment model (4.0% vs. 4.5%). In patients with normal LV function, LVDI was significantly lower than in those with DCM, irrespective of LBBB. Although LBBB resulted in a nearly 2-fold increase in LVDI in patients with normal LV function, its effects were nonsignificant in DCM. All patients with DCM and ejection fraction Conclusions Normal values established in this study resulted in indiscriminate diagnosis of abnormal dyssynchrony in all patients with reduced LV function. The value of RT3DE-derived LVDI in the evaluation of dyssynchrony in patients with reduced LV function needs to be critically reassessed because of the inability to accurately detect end-ejection in low-amplitude regional volume curves. Alternative indices of dyssynchrony need to be developed to address this limitation.

ObjectivesThis study sought to investigate the prevalence and mechanisms underlying right ventricular (RV) dyssynchrony in arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) using tissue Doppler echocardiography (TDE).BackgroundAn ARVD/C is characterized by fibrofatty replacement of RV myocardium and RV dilation. These pathologic changes may result in electromechanical dyssynchrony.MethodsEchocardiography, both conventional and TDE, was performed in 52 ARVD/C patients fulfilling Task Force criteria and 25 control subjects. The RV end-diastolic and -systolic areas, right ventricular fractional area change (RVFAC), and left ventricular (LV) volumes and function were assessed. Mechanical synchrony was assessed by measuring differences in time-to-peak systolic velocity (TSV) between the RV free wall, ventricular septum, and LV lateral wall. An RV dyssynchrony was defined as the difference in TSVbetween the RV free wall and the ventricular septum, >2 SD above the mean value for control subjects.ResultsThe mean difference in RV TSVwas higher in ARVD/C compared with control subjects (55 ± 34 ms vs. 26 ± 15 ms, p < 0.001). Significant RV dyssynchrony was not noted in any of the control subjects. Based on a cutoff value of 56 ms, significant RV dyssynchrony was present in 26 ARVD/C patients (50%). Patients with RV dyssynchrony had a larger RV end-diastolic area (22 ± 5 cm2vs. 19 ± 4 cm2, p = 0.02), and lower RVFAC (29 ± 8% vs. 34 ± 8%, p = 0.03) compared with ARVD/C patients without RV dyssynchrony. No differences in QRS duration, LV volumes, or function were present between the 2 groups.ConclusionsAn RV dyssynchrony may occur in up to 50% of ARVD/C patients, and is associated with RV remodeling. This finding may have therapeutic and prognostic implications in ARVD/C.

Dobutamine stress echocardiography (DSE) has the potential to stratify patients with low-gradient aortic stenosis (AS) but little is known about ventricular dyssynchrony associated with AS. We report the case of a patient who presented AS associated with left ventricular (LV) dyssynchrony. A DSE was performed, which showed no contractile reserve but an increase in LV dyssynchrony. In this patient, the reduced aortic valve area was probably because of the association of inadequate forward stroke volume due to ischaemic cardiomyopathy and fixed severe AS. The cause of LV dysfunction may include a certain degree of intrinsic myocardial dysfunction due to ischaemic cardiomyopathy and afterload mismatch associated with dynamic LV dyssynchrony, which could be a determinant of forward stroke volume response.

Objectives The aims of this study were to test the hypotheses that in the postoperative period after coronary artery bypass graft surgery (1) atrio–right ventricular (RA-RV) pacing induces a decrease in cardiac output compared with RA pacing alone and (2) atrio-biventricular (RA-BiV) pacing improves CO compared with RA-RV pacing. Design A prospective observational study. Setting A single-center university hospital. Participants Patients referred for coronary artery bypass graft surgery. Interventions Patients were studied during atrial, RA-RV, and RA-BiV pacing. Cardiac output (echocardiography) and left ventricular dyssynchrony were assessed at each step. Measurements and Main Results RA-RV pacing induced a significant decrease in cardiac output (4.3 ± 1.0 to 3.7 ± 0.8 L/min, p < 0.01) and a significant increase in left ventricular dyssynchrony (13 ± 12 to 80 ± 25 milliseconds, p < 0.01). Biventricular pacing induced a significant increase in cardiac output (3.7 ± 0.8 to 4.5 ± 1.0 L/min, p < 0.01) and a significant decrease in left ventricular dyssynchrony compared with right ventricular pacing (80 ± 25 to 21 ± 16 milliseconds, p < 0.05). Conclusions RA-BiV pacing improves cardiac output compared with RA-RV pacing in the postoperative period after coronary artery bypass graft surgery. This improvement is related to an improvement in left ventricular synchronicity.

The acute adverse effects of left ventricular (LV) dyssynchrony on cardiac performance were first described in 1925 by Carl Wiggers1. In recent years, the accurate diagnosis of LV dyssynchrony has become the focus of a myriad of publications, driven by the advent of cardiac resynchronization therapy (CRT) to treat heart failure due to severe LV dysfunction in the setting of marked prolongation of the QRS interval2–4. In the initial large clinical trials of CRT, QRS duration was used as a measure of dyssynchrony to select patients for treatment2, 3. However, sensitivity5 and specificity6 of QRS duration to predict response to CRT were less than optimal. Subsequently, numerous “time-to-peak” parameters based directly on the motion of the LV walls were developed to diagnose LV mechanical dyssynchrony with echocardiography in an attempt to improve CRT selection criteria7. Echocardiographic mechanical dyssynchrony parameters initially showed promise in predicting response to CRT in single-center studies8–12. However, the multicenter Predictors of Response to CRT (PROSPECT) study recently reported that no echocardiographic dyssynchrony parameter could be recommended to improve patient selection for CRT beyond current guidelines13. In addition, the Resynchronization Therapy in Narrow QRS (RETHINQ) trial recently reported that patients with narrow QRS and evidence of mechanical dyssynchrony do not benefit from CRT14. So where do we go from here? Should selection of patients for CRT based on mechanical dyssynchrony be abandoned in the wake of the negative results from PROSPECT and RETHINQ? We believe that techniques to quantify LV mechanical dyssynchrony need to be refined, not forgotten, and will still play a role in improving CRT selection criteria in the future. This refinement of dyssynchrony quantification requires a paradigm shift. First, time-to-peak methods for quantifying dyssynchrony utilize only a single time point on the velocity or strain curves and should be replaced with more quantitatively sophisticated methods. Utilizing more data reduces variability and increases accuracy. Second, “response to CRT” should no longer be considered synonymous with “presence of left ventricular dyssynchrony”. There is no method based on LV dyssynchrony measures that by itself will predict response to CRT with high accuracy.

The assessment of LV dyssynchrony through a variety of advanced imaging modalities has garnered substantial interest, as current dyssynchrony markers remain equivocal for predicting response to CRT in patients with advanced heart failure. Current recommendations support the use of CRT in symptomatic patients with moderate-to-severe heart failure, New York Heart Association functional class III or IV, QRS duration greater or equal 120 ms and an ejection fraction less or equal to 35%, who have been optimized with medical therapy. This device-based therapy has important therapeutic benefits, including functional and clinical.

Cardiac resynchronization therapy (CRT) is an accepted treatment modality in patients with endstage heart failure despite optimal pharmacologic therapy. Although considerable benefit of CRT has been demonstrated in large clinical trials, a substantial cohort of patients failed to respond to CRT. Accordingly, studies have focused on potential predictors for CRT response, and the relative merits of left ventricular dyssynchrony, viability, and scar tissue for CRT response have been demonstrated. Nuclear cardiology techniques can provide this information, particularly gated myocardial perfusion single photon emission CT with phase analysis, and this technique can be used to improve selection of CRT candidates. Also, nuclear imaging can be used to evaluate effects of CRT (changes in blood flow, oxidative metabolism, glucose utilization, and sympathetic innervation). The use of nuclear imaging in selection of CRT patients, and evaluation of CRT effects, are reviewed here.

Background: Right ventricular (RV) pacing may be detrimental to ventricular function. However, the acute effects of electromechanical dyssynchrony on RV function are not well characterized in children. We studied acute effects of electromechanical dyssynchrony, induced by RV apical and RV outflow pacing, in children with normal hearts, evaluating electromechanical synchrony, hemodynamic response, and RV function. Methods: Seventeen children (mean ± SD, 12 ± 4 years) with normal cardiac structure/function were paced after accessory pathway ablation, at baseline (AOO), and with AV pacing (DOO) from the RV apex and RV outflow. QRS duration was determined from surface ECG. Intra- and interventricular mechanical dyssynchrony and regional ventricular function were determined using tissue Doppler imaging. Global RV systolic and diastolic functions were assessed by RV dP/dTmax and RV dP/dTneg using pressure-tipped transducers. Regional RV function was assessed by tissue Doppler imaging. Cardiac index (CI) and blood pressures were measured. Results: RV apical and outflow pacing induced significant electromechanical dyssynchrony manifested by lengthening of the QRS duration, increased LV intraventricular delay (49 ± 34 ms, 53 ± 43 ms, respectively, P < 0.001), and increased interventricular delay (60 ± 29 ms, 55 ± 37 ms, P < 0.0001) versus AOO pacing. However, there was no change in blood pressure, CI, RV dp/dTmax, RV dP/dTneg, or regional tissue Doppler velocities, indicating preserved hemodynamics and preserved global and regional RV systolic and diastolic function. Conclusions: In children with normal cardiac function and structure, pacing-induced electromechanical dyssynchrony did not acutely affect RV systolic and diastolic function and did not acutely alter global hemodynamics. Therefore, electromechanical dyssynchrony may only be an important therapeutic target in the setting of decreased RV function.

Cardiac resynchronization therapy (CRT) is proved to prevent heart transplantation in some patients with dilated cardiomyopathy and mechanical dyssynchrony. We report of the benefit of CRT accomplished by atrial synchronized single-site left ventricular pacing in an 8-year-old boy with idiopathic dilated cardiomyopathy, normal atrioventricular conduction, borderline QRS complex duration (120 ms), and marked mechanical left ventricular dyssynchrony proved by echocardiographic speckle tracking.

Cardiac resynchronization therapy (CRT) offers proven benefit to patients with refractory symptomatic chronic heart failure (New York Heart Association Class III or IV), severe left ventricular (LV) systolic dysfunction (LV ejection fraction35%), and LV dyssynchrony (QRS width120 ms). Cardiac resynchronization therapy has the potential to improve survival and functional capacity, reduce hospital admissions, and promote LV reverse remodelling. Although difficult to truly evaluate, up to 30% of patients do not attain symptomatic benefit. Factors associated with a poor outcome include inappropriate patient selection, inadequate device programming, presence of myocardial scar, and suboptimal LV lead placement. Left ventricular dyssynchrony is an important determinant of CRT response, although at present no reliable single measure to identify patients beyond QRS width has been identified. In this review, we discuss the effect of LV lead placement to pace the region of maximal dyssynchrony, the impact of total scar burden on response, and the relationship between LV lead position and localized scar. Consideration is also given to prospectively defining placement of the LV lead including surgical epicardial lead positioning.

Factorial phase analysis (FaPI) represents an alternative method to Fourier phase analysis (FoPI) in the evaluation and detection of abnormalities on cardiac contraction patterns, but it has limitations in representing the sequence in abnormal contraction patterns. In this work we propose a modified factorial phase image (FaPIm) that incorporates more complete information regarding the ventricular contraction sequence. In particular, we analyze and evaluate the contribution of the third eigenimage, in the presence of ventricular dyssynchrony, which has not been sufficiently explored in the literature. We have validated the proposed FaPIm using two Equilibrium Radionuclide Angiography (ERNA) sets of images obtained with a dynamic cardiac phantom and with a numerically simulated phantom. Also, we have tested the proposed representation for a control group of 23 normal subjects and for a sample of 15 patients with Complete Left Bundle Branch Block (LBBB). Whereas FoPI allows us to obtain an image that synthesizes ventricular contraction with the smallest dispersion around the mean values, FaPI and FaPIm show that external areas surrounding ventricular cavities present more dephasing than the rest of the ventricular region and contain more detailed information about the progression of contraction. Also, in the presence of an abnormal contraction pattern, the magnitude of the third eigenvalue was greater than the corresponding eigenvalue obtained for normal simulations. The dispersion plots obtained for a normal contraction pattern show that left ventricle (LV) and right ventricle (RV) information overlap. Therefore, when there is a dyssynchrony between LV and RV contraction it becomes necessary to incorporate the information corresponding to the third factor to achieve a clear separation between regions. In the comparison of the indices of control and LBBB populations, FaPIm shows significant differences in five out of six contraction indices, showing its promising value as a clinical tool.

Patients after repair of congenital right heart disease (CRHD) may exhibit left ventricular (LV) dyssynchrony (LVD). However, the diagnosis of LVD is difficult and its reliability limited because current methods do not assess LVD of the whole LV simultaneously. The aim of the study was to assess LVD according to a novel global systolic dyssynchrony index (SDI) derived from real-time 3-dimensional echocardiography in patients after repaired CRHD.Two-dimensional echocardiography and real-time 3-dimensional echocardiography were performed in 30 patients after CRHD repair and in 30 matched healthy controls. Real-time 3-dimensional echocardiography data sets provided time-volume curves, and 2 global SDIs were derived from the dispersion of time to reach minimal systolic volume according to a 16- or 17-LV segment model.Both SDIs were significantly elevated in the patient as compared with the control group (P.001). A cutoff value for both SDIs was calculated and LVD defined as one of the SDIs exceeding cutoff. Left ventricular dyssynchrony was present in 5 (100%) of 5 patients with a LV ejection fraction (EF)50% and 13 (52%) of 25 patients with preserved LVEF, thus being diagnosed in a total of 18 (60%) of 30 patients. Moreover, patients with LVD showed a significantly higher degree of pulmonary regurgitation (P = .01) with elevated right ventricular volumes and altered septal motion. Stepwise multivariate analysis identified LVEF (P = .005) and the degree of pulmonary regurgitation (P = .02) as independent predictors of LVD.Left ventricular dyssynchrony can be detected in about 60% of patients after CRHD repair and is mainly due to significant pulmonary regurgitation resulting in an altered septal motion and systolic LV function.

Background: Right ventricular (RV) apical pacing deteriorates left ventricular (LV) function. RV nonoutflow (low) septal pacing may better preserve ventricular performance, but this has not been systematically tested. Our aim was to assess (1) whether long-term RV lower septal pacing is superior to RV apical pacing regarding LV volumes and ejection fraction (EF), and (2) if the changes in LV dyssynchrony imposed by pacing are related to the long-term changes in LV volumes and EF. Methods: In thirty-six patients with atrioventricular (AV) block, a dual-chamber pacemaker was implanted. The ventricular electrode was placed either at the apex or at the lower septum, in a randomized sequence. Twenty-four to 48 hours following implantation, we measured LV volumes, EF, and LV dyssynchrony (by tissue Doppler imaging), both with and without pacing. Patients were reassessed echocardiographically after 12 months. Results: Lower septal pacing induced a more synchronized pattern of LV contraction changes (P < 0.05). Following 12 months, differences were observed between groups regarding LV volumes and EF. EF increased within the septal group (from 52 ± 3.3% to 59 ± 3.0%, P < 0.05). A significant inverse relation was documented between changes in LV dyssynchrony and changes in EF (r =−0.64, P < 0.05). Conclusions: In patients with AV block, RV nonoutflow septal pacing represents an attractive alternative, since it preserves better and may even improve LV volumes and EF. Late changes in EF are associated with the changes in LV dyssynchrony imposed by pacing.

In recent years, concerns have been raised about possible harmful effects of long-term right ventricular (RV) apical pacing. These detrimental effects may be related to changes in left ventricular (LV) mechanics during RV apical pacing. As a consequence, alternative RV pacing sites have been proposed, and in selected patients an upgrade from RV to biventricular pacing may be considered. Novel two-dimensional (2D) speckle tracking strain imaging allows detailed evaluation of LV mechanics, including LV mechanical dyssynchrony, LV strain and LV torsion. In this review, the role of speckle tracking strain imaging in the evaluation of LV function in patients with RV apical pacing will be reviewed. The effects of RV apical pacing on LV mechanical dyssynchrony, LV strain and LV torsion will be discussed. In addition, the role of speckle tracking strain imaging in the selection of the optimal (alternative) RV pacing site and in the selection of patients who may benefit from an upgrade from RV apical pacing to biventricular pacing will be reviewed.

SummaryWe report here a case of pilsicainide intoxication presenting as left ventricular dyssynchrony in a patient who had been treated on hemodialysis. This is the first report that assessed cardiac function during pilsicainide intoxication by left ventriculography and right heart catheterization.

International audience; AIMS: We sought to develop and validate a multiparametric algorithm by applying previously validated criteria to predict cardiac resynchronization therapy (CRT) response in a multicentre study. Thirty per cent of patients treated by CRT fail to respond to the treatment. Although dyssynchrony by echocardiography has been used to improve the selection of patients, the complexity of myocardial contraction has generated a moderate improvement using any of several individual parameters. METHODS AND RESULTS: Two hundred end-stage heart failure patients [NYHA 3-4 and left ventricular ejection fraction (LVEF)120 ms were included. Echocardiography analysis focused on the following parameters: atrioventricular dyssynchrony, interventricular dyssynchrony, and intraventricular dyssynchrony that integrated radial (PSAX M-mode) and longitudinal [tissue Doppler imaging (TDI)] evaluations for spatial (wall to wall) and temporal (wall end-systole to mitral valve opening) dyssynchrony diagnosis. Following CRT implantation, patients were monitored for 6 months with functional and echo evaluations defining responders by a 15% reduction in end-systolic volume. Mean QRS duration and LVEF were 152 +/- 17 ms and 25 +/- 8%. There was a CRT response in 57% of patients, independent of QRS width. Mean prevalence of positive criteria was 34 +/- 8%. Feasibility and variability averages were 81 +/- 20% and 9 +/- 4%. In a single parametric approach, ranges of sensitivities and specificities were 18-65% and 45-84% with a mean of 41% and 66%. A multiparametric approach by focusing on criteria combination decreased the mean rate of false-positive results to 14 +/- 12%, 5 +/- 4%, 2 +/- 2%, and 1 +/- 2% from one to four parameters, respectively. More than three parameters were associated with a specificity above 90% and a positive predictive value above 65%. Reproducibility of this global strategy was 91%. CONCLUSION: A multiparametric echocardiographic strategy based on the association of conventional criteria is a better indicator of CRT response than the existing single parametric approaches.

International audience; AIMS: Mitral regurgitation (MR) is common and independently predicts mortality in patients with left ventricular (LV) systolic dysfunction. Its management remains challenging because of the complexity and variety of potential mechanisms implicated. We sought to determine which LV functional characteristics are the most important determinants of the severity of the MR associated with dilated cardiomyopathies. METHODS AND RESULTS: We performed echocardiographic studies in 87 consecutive patients with dilated cardiomyopathy. The degree of MR was quantified according to guidelines. LV, left atrial and mitral annulus dimensions, mitral valve tenting, estimated filling pressures, regional myocardial contractility, and dyssynchrony (using regional strain (epsilon) analysis) were recorded too. Determinants of significant MR was thus assessed using multivariate models. Mitral regurgitant volume correlated with mitral annulus diameter (P

BACKGROUND Recently, cardiac resynchronization therapy, by using biventricular pacemakers, has become implemented in the treatment of patients with severe heart failure. However, using the classical inclusion criteria, 30 % of patients treated with resynchronization do not improve symptoms or activity level. Phase analysis of radionuclide ventriculography gives information about pattern of ventricular contraction and may detect dyssynchrony. The method may therefore be used to select patients with dyssynctrony to resynchronization therapy. In this study we have investigated the amount of dyssynchrony, by using phase analysis of radionuclide ventriculography, in men and women as a function of left ventricular ejection fraction. MATERIAL AND METHODS The study is based on 1 266 radionuclide ventriculographies performed at Section of Nuclear Medicine, University Hospital North-Norway, during 1998 - 2006. The relationship between left ventricular ejection fraction and number of patients with ventricular dyssynchrony was investigated. 90 patients with no known heart problems were considered as reference values for synchrony data. RESULTS The phase analysis showed that 35 % of the women and 34 % of the men with left ventricular ejection fraction below 35 % had both inter- and intra-ventricular dyssynchrony. INTERPRETATION Today's criteria for including patients to resynchonizing therapy are not good enough. Phase analysis of radionuclide ventriculography of patients with left ventricular ejection fraction below 35 % shows that one third of the patients have both inter- and intra- ventricular dyssynchrony. These patients might be responders to resynchronization therapy.

Background: Tissue synchronizing imaging (TSI) allows visual detection of asynchronous myocardial contraction. Although it is a screening tool for the detection of left ventricular (LV) dyssynchrony, its use as a qualitative method to assess dyssynchrony has not been studied. We evaluated the correlation of the visual assessment of dyssynchrony using TSI with quantitative assessment, the value of visual assessment to predict reverse remodeling to cardiac resynchronization therapy (CRT). Methods: Echocardiograms from 100 consecutive patients were retrospectively evaluated. We compared visual TSI assessment with the qualitative assessment of dyssynchrony obtained by tissue Doppler imaging (TDI). The utility of visual assessment as a predictor of response to CRT was evaluated in 43 patients. Results: In 86% of the cases, visual assessment was possible, and reproducibility was unrelated to observer experience. Each grade of visual dyssynchrony corresponded to a range of values of time to peak velocity (TPV) gradient (p < 0.001). Grade ≥1 dyssynchrony by visual assessment had 90% sensitivity and 95% specificity to identify ≥65 ms TPV gradient of LV opposing walls, and 93% sensitivity and 70% specificity to predict reverse LV remodeling. Conclusion: LV dyssynchrony may be visually assessed by TSI, which can also predict reverse LV remodeling.

The significance of left ventricular (LV) dyssynchrony for the prediction of response to cardiac resynchronization therapy (CRT) has been demonstrated. Parameters reflecting LV dyssynchrony (phase SD, histogrambandwidth) can be derived from gated myocardial perfusion SPECT (GMPS) using phase analysis. The feasibility of LV dyssynchrony assessment with phase analysis on GMPS using Quantitative Gated SPECT (QGS) software has not been demonstrated in patients undergoing CRT. The aim of the present study was to validate the QGS algorithm for phase analysis on GMPS in a direct comparison with echocardiography using tissue Doppler imaging (TDI) for LV dyssynchrony assessment. Also, prediction of response to CRT using GMPS and phase analysis was evaluated. Methods: Patients (n = 40) with severe heart failure (New York Heart Association class III-IV), an LV ejection fraction of no more than 35%, and a QRS complex greater than or equal to 120 ms were evaluated for LV dyssynchrony using GMPS and echocardiography with TDI. At baseline and after 6 mo of CRT, clinical status, LV volumes, and LV ejection fraction were evaluated. Patients with functional improvement were classified as CRT responders. Results: Both histogram bandwidth (r = 0.69, r(2) = 0.48, SEE = 25.4, P < 0.01) and phase SD (r = 0.65, r(2) = 0.42, SEE = 26.8, P < 0.01) derived from GMPS correlated significantly with TDI for assessment of LV dyssynchrony. At baseline, CRT responders showed a significantly larger histogram bandwidth (94 degrees +/- 23 degrees vs. 68 degrees +/- 21 degrees, P < 0.01) and a larger phase SD (26 degrees +/- 6 degrees vs. 18 degrees +/- 5 degrees, P < 0.01) than did nonresponders. Receiver-operating-characteristic curve analysis identified an optimal cutoff value of 72.5 degrees for histogram bandwidth to predict CRT response, yielding a sensitivity of 83% and a specificity of 81%. For phase SD, sensitivity and specificity similar to those for histogram bandwidth were obtained at a cutoff value of 19.6 degrees. Conclusion: QGS phase analysis on GMPS correlated significantly with TDI for the assessment of LV dyssynchrony. Moreover, a high accuracy for prediction of response to CRT was obtained using either histogram bandwidth or phase SD.

Aims Cardiac dyssynchrony is common in patients with heart failure, whether or not they have ischaemic heart disease (IHD). The effect of the underlying cause of cardiac dysfunction on the response to cardiac resynchronization therapy (CRT) is unknown. This issue was addressed using data from the CARE-HF trial. Methods and results Patients ( n = 813) were grouped by heart failure aetiology (IHD n = 339 vs. non-IHD n = 473), and the primary composite (all-cause mortality or unplanned hospitalization for a major cardiovascular event) and principal secondary (all-cause mortality) endpoints analysed. Heart failure severity and the degree of dyssynchrony were compared between the groups by analysing baseline clinical and echocardiographic variables. Patients with IHD were more likely to be in NYHA class IV (7.5 vs. 4.0%; P = 0.03) and to have higher NT-proBNP levels (2182 vs. 1725 pg/L), indicating more advanced heart failure. The degree of dyssynchrony was more pronounced in patients without IHD (assessed using mean QRS duration, interventricular mechanical delay, and aorta-pulmonary pre-ejection time). Left ventricular ejection fraction and left ventricular end-systolic volume improved to a lesser extent in the IHD group (4.53 vs. 8.50% and −35.68 vs. –58.52 cm3). Despite these differences, CRT improved all-cause mortality, NYHA class, and hospitalization rates to a similar extent in patients with or without IHD. Conclusion The benefits of CRT in patients with or without IHD were similar in relative terms in the CARE-HF study but as patients with IHD had a worse prognosis, the benefit in absolute terms may be greater.

ObjectivesWe sought to determine the feasibility of cardiac computed tomography (CT) to detect significant differences in the extent of left ventricular dyssynchrony in heart failure (HF) patients with wide QRS, HF patients with narrow QRS, and age-matched controls.BackgroundThe degree of mechanical dyssynchrony has been suggested as a predictor of response to cardiac resynchronization therapy. There have been no published reports of dyssynchrony assessment with the use of CT.MethodsThirty-eight subjects underwent electrocardiogram-gated contrast-enhanced 64-slice multidetector CT. The left ventricular endocardial and epicardial boundaries were delineated from short-axis images reconstructed at 10% phase increments of the cardiac cycle. Global and segmental CT dyssynchrony metrics that used changes in wall thickness, wall motion, and volume over time were assessed for reproducibility. We defined a global metric using changes in wall thickness as the dyssynchrony index (DI).ResultsThe DI was the most reproducible metric (interobserver and intraobserver intraclass correlation coefficients ≥0.94, p < 0.0001) and was used to determine differences between the 3 groups: HF-wide QRS group (ejection fraction [EF] 22 ± 8%, QRS 163 ± 28 ms), HF-narrow QRS (EF 26 ± 7%, QRS 96 ± 11 ms), and age-matched control subjects (EF 64 ± 5%, QRS 87 ± 9 ms). Mean DI was significantly different between the 3 groups (HF-wide QRS: 152 ± 44 ms, HF-narrow QRS: 121 ± 58 ms, and control subjects: 65 ± 12 ms; p < 0.0001) and greater in the HF-wide QRS (p < 0.0001) and HF-narrow QRS (p = 0.005) groups compared with control subjects. We found that DI had a good correlation with 2-dimensional (r = 0.65, p = 0.012) and 3-dimensional (r = 0.68, p = 0.008) echocardiographic dyssynchrony.ConclusionsQuantitative assessment of global CT-derived DI, based on changes in wall thickness over time, is highly reproducible and renders significant differences between subjects most likely to have dyssynchrony and age-matched control subjects.