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Focuses on the clinical significance of multiple sensor options for improved heart rate modulation. Multiple sensor option and rate optimization; Sensor blending; Automaticity and sensor blending.

Electrical Impact of the Left Ventricular Pacing Site in CRT Introduction Recent studies have demonstrated that left ventricular (LV) pacing site is a critical parameter in optimizing cardiac resynchronization therapy (CRT). The present study evaluates the effect of pacing from different LV locations on QRS duration (QRSd) and their relationship to acute hemodynamic response in congestive heart failure patients. Methods and Results Thirty-five patients with nonischemic dilated cardiomyopathy and left bundle branch block referred for CRT device implantation were studied. Eleven predetermined LV pacing sites were systematically assessed in random order: epicardial: coronary sinus (CS); endocardial: basal and mid-cavity (septal, anterior, lateral, and inferior), apex, and the endocardial site facing the CS pacing site. For each patient QRSd and +dP/dtmax during baseline (AAI) and DDD LV pacing at 2 atrioventricular delays were compared. Response to CRT was significantly better in patients with wider baseline QRSd (≥150 milliseconds). Hemodynamic response was inversely correlated to increase of QRSd during LV pacing (short atrioventricular [AV] delay: r = 0.44, P < 0.001; long AV delay: r = 0.59, P < 0.001). Compared to baseline, LV pacing at the site of shortest QRSd significantly improved +dP/dtmax (+18 ± 25%, P < 0.001) but was not superior to other conventional strategy (lateral wall, CS pacing, and echo-guided) and was inferior to a hemodynamically guided strategy. Conclusions In our study, we have demonstrated that changes of QRSd during LV pacing correlated with acute hemodynamic response and that LV pacing location was a primary determinant of paced QRSd. Although QRSd did not predict the maximum hemodynamic response, our results confirm the link between electrical activation and hemodynamic response of the LV during CRT. [ABSTRACT FROM AUTHOR]

Depression and Cardiac Resynchronization Therapy. Background: The relationship between depression and heart failure is neither coincidental nor trivial, since depression is a powerful predictor of re-hospitalization and mortality. We prospectively studied the prevalence and impact of depression on the clinical outcomes of patients attending for cardiac resynchronization therapy (CRT). We specifically examined whether patients with depression have a different rate of response to CRT and whether CRT has an effect on depressive symptoms. Methods: Sixty-eight recipients of CRT systems were included. The depressive status was evaluated before implant and after 6 months by a structured diagnostic interview measuring Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) criteria of major depression and by a self-report questionnaire (Center for Epidemiological Studies Depression Scale, CES-D). The CRT response was assessed at 6 months by a clinical composite score. Results: At inclusion, DSM-IV criteria of major depression were identified in 41% of the population, while using the self-report questionnaire 65% were observed to have mild to major depressive symptoms (CES-D ≥ 16). Only 4 patients were taking antidepressants. At 6 months, 75% were considered responders to CRT. Response to CRT did not differ between those with and without depression at baseline. The rate of patients with depression at 6 months was significantly lower in responders to CRT compared with nonresponders. Conclusions: We found a high prevalence of depressive symptoms in patients receiving CRT systems. Patients with depression should not be excluded from CRT, because they demonstrate a similar rate of response than the persons without depression and the responders are less likely to be depressed at 6 months. (J Cardiovasc Electrophysiol, Vol. 23, pp. 631-636, June 2012) [ABSTRACT FROM AUTHOR]

A response by Akihiko Kandori et al to a letter to the editor about their article on a method of risk-stratification of asymptomatic individuals with Brugada syndrome is presented.

Cardiac pacemakers with preerosion are often reimplanted. Preerosion may be caused by an evolving local infectious process affecting the entire pacing system or by mechanical migration of the device causing ischemic necrosis of the skin tissues. We examined the long-term outcome of 33 patients who underwent pocket or scar revision and submuscular reimplantation of cardiac pacemakers in our institution. Before undergoing pocket or scar revision and reimplantation, all patients (1) had negative serial blood cultures, (2) had no vegetation on transesophageal echocardiography, (3) had a normal blood C-reactive protein concentrations, (4) were afebrile, (5) had no cutaneous breakthrough, and (6) presented with preerosion of the pulse generator or granulomatous-like scar abnormality. The mean follow-up was 37 ± 12 months. Among 16 patients presenting with preerosion associated with signs of local cutaneous inflammation, 62.5% developed an infection of the pacing system requiring later explantation. Of eight patients presenting initially with migration of the pulse generator and mechanical protrusion, none required subsequent explantation of the system. Among nine patients presenting initially with granulomatous-like scar abnormalities, 55.6% underwent explantation of the pacing system during follow-up for management of documented local infection. The reimplantation of pulse generators with preerosion in the presence of local inflammatory manifestations or granulomatous-like changes of the scar is complicated by documented cardiac pacemaker infection in >50% of cases. In these patients, the explantation of the pacing system is recommended before the development of prognostically much more serious spread of infection to the leads and cardiac tissues. (PACE 2011; 34:150-154) [ABSTRACT FROM AUTHOR]

Objectives: This study describes 5-year follow-up results of catheter ablation for atrial fibrillation (AF). Background: Long-term efficacy following catheter ablation of AF remains unknown. Methods: A total of 100 patients (86 men, 14 women), age 55.7 ± 9.6 years, referred to our center for a first AF ablation (63% paroxysmal; 3.5 ± 1.4 prior ineffective antiarrhythmic agents) were followed for 5 years. Complete success was defined as absence of any AF or atrial tachycardia recurrence (clinical or by 24-h Holter monitoring) lasting ≥30 s. Results: Arrhythmia-free survival rates after a single catheter ablation procedure were 40%, 37%, and 29% at 1, 2, and 5 years, respectively, with most recurrences over the first 6 months. Patients with long-standing persistent AF experienced a higher recurrence rate than those with paroxysmal or persistent forms (hazard ratio [HR]: 1.9, 95% confidence interval [CI]: 1.0 to 3.5; p = 0.0462). In all, 175 procedures were performed, with a median of 2 per patient. Arrhythmia-free survival following the last catheter ablation procedure was 87%, 81%, and 63% at 1, 2, and 5 years, respectively. Valvular heart disease (HR: 6.0, 95% CI: 2.0 to 17.6; p = 0.0012) and nonischemic dilated cardiomyopathy (HR: 34.0, 95% CI: 6.3 to 182.1; p < 0.0001) independently predicted recurrences. Major complications (cardiac tamponade requiring drainage) occurred in 3 patients (3%). Conclusions: In selected patients with AF, a catheter ablation strategy with repeat intervention as necessary provides acceptable long-term relief. Although most recurrences transpire over the first 6 to 12 months, a slow but steady decline in arrhythmia-free survival is noted thereafter. [ABSTRACT FROM AUTHOR]

Aims: A recent study suggested that no single echocardiographic index of cardiac dyssynchrony can reliably identify candidates for cardiac resynchronization therapy (CRT). We examined the value of three simple echocardiographic indices for predicting the 6-month clinical and echocardiographic responses to CRT. [ABSTRACT FROM PUBLISHER]

Introduction: Recent expert consensus guidelines mention that one of the principles for infected device replacement following removal is to “reevaluate carefully if there is a continued need for a new cardiac device replacement.” This is a Class I recommendation, which nevertheless suffers from a very low level of evidence (level of evidence C), since no study has revisited the systematic practice of reimplanting the same device based on a meticulous clinical reassessment. In the present paper, we examined the safety of withholding the implantation of pacing systems in selected patients. Methods and Results: Between January 2005 and December 2007, 188 consecutive patients underwent extractions of infected pacing systems at 2 medical centers. “Low-risk” patients were identified by (1) a spontaneous heart rate >45 bpm, (2) no symptomatic asystole during monitoring, (3) QRS duration <120 ms when history of AV block was noted, (4) no high-degree AV block during continuous monitoring. They remained device-free, unless an adverse clinical event occurred mandating the reimplantation. The primary study endpoint was rate of sudden death and syncope after a 12-month follow-up. Among the 74 (39.4%) “low-risk” patients, a single patient suffered a bradycardia-related syncopal event corresponding to a 1.3% (95% CI, 0.0–3.9) rate of primary endpoint. Pacing systems were also reimplanted in 24 patients (32.4%) for syncope (n = 1), nonsevere bradycardia-reated symptoms (n = 17), cardiac resynchronization (n = 2), and for reassurance in 4 asymptomatic patients. Conclusion: After removal of infected pacing systems, these preliminary data demonstrated that a strategy of nonsystematic device reimplantation associated with close surveillance was safe in “low-risk” patients, allowing the administration of antimicrobials in a device-free state. (J Cardiovasc Electrophysiol, Vol. 21, pp. 540-544, May 2010) [ABSTRACT FROM AUTHOR]

Cardiac resynchronization therapy (CRT) has been shown to induce a spectacular effect on left ventricular (LV) function in certain patients. Our aim was to analyze and characterize the super-responders (SRs) to CRT using echocardiography in 186 patients with a conventional indication according to the European Society Cardiology guidelines. The investigation took place before and 6 months after implantation. CRT-SRs were defined by an improvement of the New York Heart Association functional class and LV ejection fraction to ≥50% in absolute values associated with a relative LV end-systolic volume reduction of ≥15%. Of the 186 patients, 18 (9.7%) were identified as CRT-SRs and had a significantly lower prevalence of ischemic etiology (11%), lower LV dimensions, lower left atrial volume, and greater global longitudinal strain at baseline. Receiver operating characteristics curves identified global longitudinal strain as the strongest parameter for predicting CRT-SRs, with a cutoff value of −12% (area under the curve 0.87, sensitivity 71%, and specificity 85%, p <0.01). In conclusion, in the present retrospective study, only a left atrial volume <55 ml and global longitudinal strain ≤−12% were independent predictors of CRT-SRs. [Copyright &y& Elsevier]

Objectives: We sought to evaluate the impact of the left ventricular (LV) pacing site on hemodynamic response to cardiac resynchronization therapy (CRT). Background: CRT reduces morbidity and mortality in heart failure patients. However, 20% to 40% of eligible patients may not fully benefit from CRT device implantation. We hypothesized that selecting the optimal LV pacing site could be critical in this issue. Methods: Thirty-five patients with nonischemic dilated cardiomyopathy referred for CRT device implantation were studied. Intraventricular dyssynchrony and latest activated LV wall were defined by tissue Doppler imaging analysis before the study. Eleven predetermined LV pacing sites were systematically assessed in random order: basal and mid-cavity (septal, anterior, lateral, inferior), apex, coronary sinus (CS), and the endocardial site facing the CS pacing site. For each patient, +dP/dTmax, −dP/dTmin, pulse pressure, and end-systolic pressure during baseline (AAI) and DDD LV pacing were compared. Two atrioventricular delays were tested. Results: Major interindividual and intraindividual variations of hemodynamic response depending on the LV pacing site were observed. Compared with baseline, LV DDD pacing at the best LV position significantly improved +dP/dTmax (+31 ± 26%, p < 0.001) and was superior to pacing the CS (+15 ± 23%, p < 0.001), the lateral LV wall (+18 ± 22%, p < 0.001), or the latest activated LV wall (+11 ± 17%, p < 0.001). Conclusions: The pacing site is a primary determinant of the hemodynamic response to LV pacing in patients with nonischemic dilated cardiomyopathy. Pacing at the best LV site is associated acutely with fewer nonresponders and twice the improvement in +dP/dTmax observed with CS pacing. [Copyright &y& Elsevier]

Introduction: Biventricular pacing is associated with various electrocardiographic patterns depending on the position of the left ventricular (LV) lead. We aimed to develop an electrocardiogram-based algorithm to predict the position of the LV lead. Methods: The algorithm was developed in 100 consecutive recipients of cardiac resynchronization therapy (CRT) systems. QRS axis, morphology, and polarity were analyzed with a view to define the specific electrocardiographic characteristics associated with the various LV lead positions . The algorithm was prospectively validated in 50 consecutive CRT device recipients. Results: The first analysis of the algorithm was the QRS morphology in V1. A positive R wave in V1 suggested LV lateral or posterior wall stimulation. A QS pattern was specific of anterior LV leads. In the presence of an R wave in V1, V6 was analyzed to distinguish between an inferior and anterior LV lead. Inferior leads were never associated with a positive V6. To differentiate between lateral and posterior positions, we analyzed the pattern in V2. Lateral leads were associated with an R morphology in V1 and a negative V2. Posterior leads were associated with an R morphology in V1 and V2. The algorithm allowed a reliable distinction between an inferior or anterior and a lateral or posterior lead position in 90% of patients. Inferior, anterior, lateral, and posterior positions were reliably distinguished in 80% of patients. Conclusion: This algorithm predicted the position of the LV lead with a high sensitivity and predictive value. [ABSTRACT FROM AUTHOR]

Isolated paroxysmal atrial fibrillation (AF) is commonly associated with left ventricular (LV) diastolic dysfunction but normal radial systolic contraction. We aim to investigate LV systolic function more precisely using 2-dimensional strain technique in patients with isolated paroxysmal AF and to evaluate evolution of longitudinal, circumferential, and radial (or transverse) strain components after catheter ablation of AF. Thirty patients with isolated paroxysmal AF were investigated by echocardiographic studies before and at 1-day, 1-month, 6-month, and 12-month intervals after radiofrequency ablation. Left heart dimensions and LV systolic and diastolic functions were evaluated at each time interval. LV systolic function was quantified by LV ejection fraction and by 2-dimensional strain evaluation, giving regional and global longitudinal, circumferential, transverse, and radial peak of percentage deformation. Patients with AF were compared with 30 control subjects, paired by age and by sex. Before AF ablation, LV ejection fraction, transverse and radial strains were not significantly different from control subjects. By contrast, global longitudinal and circumferential strains were significantly lower than controls (−17.7% ± 2.4% vs −21.5% ± 2.0% [p <0.01] and −16.0% ± 2.9% vs −20.7% ± 3.4% [p <0.01], respectively). At the end of follow-up, global longitudinal and circumferential strains were significantly improved (−20.8% ± 2.6% vs −17.7% ± 2.4% (p <0.01) and −18.5% ± 3.1% vs −16.0% ± 2.9% [p <0.05], respectively). Global longitudinal strain was not significantly different from normal control subjects at the end of follow-up. In conclusion, this prospective study demonstrates (1) the existence of early longitudinal and circumferential LV systolic function abnormalities in patients with isolated paroxysmal AF but normal ejection fraction and (2) reverse remodeling of these abnormalities after AF ablation. [Copyright &y& Elsevier]

The development of small-diameter active fixation pacing and implantable cardioverter-defibrillator leads may be associated with increased risk for delayed right ventricular perforation. The management of this unforeseen complication has been poorly described. Eleven successive patients referred for right ventricular subacute or delayed perforation (no evidence of lead perforation at the time of the procedure, perforation of the right ventricle diagnosed ≥5 days after implantation) were reviewed. The perforation was related to a pacing (n = 7) or an implantable cardioverter-defibrillator (n = 4) lead. The main symptoms were major dyspnea with pericardial effusion requiring emergency pericardial drainage (n = 3), inappropriate implantable cardioverter-defibrillator shock (n = 1), syncope (n = 2), abdominal pain (n = 1), mammary hematoma (n = 1), diaphragm stimulation (n = 1), and chest pain (n = 1). One patient was strictly asymptomatic. Signs of lead dysfunction were observed in all 11 patients. The diagnosis of lead perforation was confirmed by chest x-ray, echocardiography, or computed tomography. Surgery was directly performed in 1 patient with suspicion of digestive perforation. In the remaining 10 patients, the leads were removed by simple traction under fluoroscopic guidance in the operating room, with surgical backup support. The need for close monitoring was highlighted by the occurrence in 1 patient of tamponade requiring percutaneous pericardiocentesis and urgent surgical revision. The postoperative course of these patients was unremarkable. In conclusion, subacute ventricular perforation is a rare but potentially life threatening complication of lead implantation. In most patients, the leads can safely be removed under fluoroscopic guidance, with surgical backup support and close monitoring. [Copyright &y& Elsevier]

Introduction: The peak of endocardial acceleration (PEA) is an index of myocardial contractility. We aimed to (1) demonstrate that the PEA measured by the noninvasive cutaneous precordial application of an accelerometer sensor is related to left ventricular (LV) d P/d t max and (2) assess the usefulness of PEA monitoring during graded ischemia and during different configurations of sequential biventricular pacing. Methods and Results: Measurements of invasive LV d P/d t max were compared with measurements of transcutaneous PEA in seven pigs at baseline and during acute drug infusions; increased heart rate; right, left, biventricular and sequential biventricular pacing before and after graded ischemia induced by the constriction of the left anterior descending coronary artery. A consistent PEA signal was obtained in all animals. PEA changes were highly related to LV d P/d t max changes ( r= 0.93; P < 0.001). The changes of LV contractility induced by the different pacing configurations were detected by PEA analysis in the absence of ischemia ( r= 0.94; P < 0.001) and in the presence of ischemic LV dysfunction ( r= 0.91; P < 0.001). Conclusion: Noninvasive PEA measurement allows monitoring of left ventricular contractility and may be a useful tool to detect global effect of ventricular ischemia and to optimize the choice of both pacing site and pacing configuration. [ABSTRACT FROM AUTHOR]

Background: Cardiac resynchronization therapy (CRT) is recommended in patients with ejection fraction <35%, QRS width> 120 ms, and New York Heart Association (NYHA) functional class III or IV despite optimal medical therapy. We aimed to define demographic, clinical, and electrocardiographic predictors of positive clinical response to CRT. Methods and Results: Hundred consecutive patients fulfilling the recommended criteria were implanted with a CRT device. Demographic, clinical, two-dimensional echocardiographic and electrographic parameters were measured at baseline and after 6 months of simultaneous biventricular pacing. A positive response to CRT included an improvement of at least one NYHA functional class associated with an absence of hospitalization for worsening heart failure. At the end of follow-up, 12 patients were dead and 71% of the patients were classified as responders. After 6 months of CRT, the ejection fraction was significantly higher (P = 0.035) in responders versus nonresponders. Multivariate analysis identified three independent predictors of positive response to CRT: an idiopathic origin of the cardiomyopathy (P = 0.043), a wider QRS before implantation (P = 0.017), and a narrowing of the QRS after implantation (P = 0.037). Conclusion: An idiopathic origin of the cardiomyopathy, a wider QRS before implantation, and a narrowing of the QRS width after implantation were identified as independent predictors of clinical positive response to CRT. [ABSTRACT FROM AUTHOR]

Introduction: Radiofrequency (RF) ablation of the cavotricuspid isthmus (CTI) can be performed using different types of ablation catheter. Gold tip electrodes have the theoretical advantage of creating bigger lesions than standard platinum-iridium electrode. This prospective, randomized study compares the clinical efficacy of 8-mm gold tip catheter, externally irrigated and 8-mm platinum-iridium tip (Pt tip) catheters. Methods and Results: Sixty consecutive patients (51 men, 60 ± 10 years) undergoing de novo CTI ablation for documented typical atrial flutter were randomized to one of the following ablation catheters: 8-mm gold tip catheter, an externally irrigated-tip (Irr. tip) catheter, or an 8-mm Pt tip catheter. The procedural endpoint was achievement of bidirectional isthmus conduction block with ≤ 20 minutes of RF energy application. The latter was achieved equally with the 3 catheters (95% for gold tip, 100% for irrigated tip, 95% for Pt tip) and the durations of RF (10 ± 6, 10 ± 4, 13 ± 8 minutes), fluoroscopy (12 ± 6, 12 ± 7, 15 ± 12 minutes) and the procedure (34 ± 23, 38 ± 24, 40 ± 30 minutes) were similar in all groups. The maximal targeted power could not be reached in at least one location in 40% of patients with gold tip and in 35% of patients with Pt tip catheters whereas it was always achieved with an Irr. tip catheter (P = 0.003, P = 0.008). The reduction in impedance during RF delivery was greater with Irr. tip (11 ± 7 Ω) than with gold (7 ± 4 Ω, P = 0.02) or Pt tip (5 ± 3 Ω, P = 0.001) catheters. Conclusion: This study demonstrates equivalent efficacies of gold, platinum-iridium and externally Irr. tip catheters for successful de novo ablation of the CTI. [ABSTRACT FROM AUTHOR]

The search for a mechanism to explain atrial fibrillation (AF) has lasted for over a century and continues. Significant progress in understanding this arrhythmia accelerated with the era of operative treatment of this arrhythmia and intensified with the advent of catheter ablation. Through considerable trial and some error, effective “curative” therapies have evolved for paroxysmal AF and are evolving for persistent AF. It is becoming clear that no single mechanism suffices to explain AF in all its forms and multiple mechanisms are playing a role in the most complicated cases. [ABSTRACT FROM AUTHOR]

Background: The incidence of endocarditis related to pacemakers is increasing, while the diagnosis and management remain difficult. The objective of this study was to evaluate the clinical features and management of endocarditis after implantation of pacemakers (PM) or cardioverter defibrillators (ICD). Methods: We analyzed the hospital course of 60 consecutive patients (48 men, mean age 68 ± 12 years) admitted to our center for PM (n = 59) or ICD (n = 1) endocarditis between 1998 and 2004. Results: Fever (78%), asthenia (65%), and local symptoms (35%) were common. Positive cultures were obtained in 53 cases (Staphylococcus 89%). Sixteen patients (27%) had pulmonary embolism. Vegetations (mean size 15.2 ± 8 mm, range 5 to 35 mm) were found in 54 cases (90%), with transthoracic echocardiography in 26 cases (43%), and transesophageal echocardiography (TEE) in 50 cases (89% of the 56 patients who had TEE). Devices were removed surgically (n = 20) or percutaneously (n = 37). In the surgical group, vegetations were larger (17.9 ± 7 mm vs 13.2 ± 7 mm, P = 0.01). After removal, 42 patients (70%) had a new PM. Mortality factors (6 deaths – follow up 3.4 ± 2 years) were the number of vegetations and absence of extraction of the device (P < 0.02). Clinical features and management of the 37 patients with early onset endocarditis (within 1 year after implantation) did not differ from those with late onset. Conclusions: PM endocarditis was essentially staphylococcal. TEE was required for the diagnosis of vegetations. Complete removal of the device is required and associated with a favorable outcome. [ABSTRACT FROM AUTHOR]

Objectives: We sought to assess the effects of exercise on ventricular dyssynchrony in patients with normal and depressed left ventricular (LV) function. Background: Asynchronous myocardial contraction adversely influences ventricular function and is associated with a poor prognosis in heart failure. Exercise-induced changes in ventricular dyssynchrony may be an important determinant of dynamic changes in cardiac output and mitral regurgitation. Methods: A total of 65 consecutive heart failure patients and 50 matched healthy control patients underwent exercise echocardiography. Conventional and tissue Doppler parameters were measured before and during symptom-limited exercise. Left ventricular dyssynchrony was defined as the standard deviation of 12 LV segmental electromechanical delays. Analysis of the control group allowed delimitation of normal cutoff values. Results: In patients with normal left ventricular function, exercise did not modify the extent of LV asynchrony. In contrast, in heart failure patients, LV dyssynchrony increased by at least 20% in 34%, remained stable in 37%, and decreased by at least 20% in 29%. Moreover, 26% of heart failure patients had either exercise induction or normalization of ventricular dyssynchrony. A significant association was found between exercise-induced changes in dyssynchrony and the presence of ischemic cardiomyopathy (p < 0.05). Rest-exercise differences in ventricular dyssynchrony were correlated with changes in cardiac output and mitral regurgitation (r = −0.63 and 0.56, respectively). Conclusions: In heart failure patients, exercise can alter the magnitude of ventricular dyssynchrony. Some patients have a response to exertion with induction of ventricular dyssynchrony, whereas others show normalization. Changes in ventricular dyssynchrony during exercise correlate with alterations in cardiac output and mitral regurgitation. [Copyright &y& Elsevier]

This prospective echocardiographic study investigated the respective impacts of left ventricular (LV) pacing and simultaneous and sequential biventricular pacing (BVP) on ventricular dyssynchrony during exercise in 23 patients with compensated heart failure and ventricular conduction delays. During exercise, LV pacing and BVP significantly (p <0.05) improved mitral regurgitation and LV dyssynchrony compared with spontaneous activation. LV segmental electromechanical delays were significantly prolonged during LV pacing, leading to increased systolic time (p <0.05), decreased LV filling time (p <0.05), and decreased stroke volume (p <0.05) compared with BVP. After optimization of the interventricular delay with sequential BVP, additional benefit was obtained during exercise in terms of stroke volume and mitral regurgitation (p <0.05). The optimal interventricular delay was different at rest and during exercise in 57% of the patients. Changes from at rest to exercise in LV dyssynchrony were correlated with changes in stroke volume (r = −0.61, p <0.01) and changes in mitral regurgitation (r = 0.60, p <0.01). [Copyright &y& Elsevier]

Background: Noninducibility of sustained atrial fibrillation (AF) after pulmonary vein isolation (PVI) has been shown to be associated with a better clinical outcome. We evaluated the role of clinical variables that could predict noninducibility of sustained AF after PVI. Methods and Results: Data were collected prospectively from 181 patients (153 male; age 54 ± 9 years) referred for ablation of drug-refractory symptomatic paroxysmal AF (duration ≤7 days). Clinical variables were evaluated with regard to their ability of predicting noninducibility of sustained AF (≤10 minutes) after PVI. Univariate analysis was performed on all collected variables followed by multivariate analysis for variables showing a P value <0.1. After PVI, sustained AF was noninducible in 97 (54%) patients. The following clinical variables showed a significant difference between the groups: body weight, longest AF episode, duration of AF history, presence or absence of structural heart disease, left ventricular (LV) hypertrophy, prior cardioversion, left atrial (LA) parasternal, and longitudinal diameters and LV diameters. On multivariate analysis, three independent predictors of noninducibility were identified: a shorter duration of AF episodes (AF <12 hours: RR 0.01 (0.002–0.06), P < 0.001; AF 12–48 hours: RR 0.07 (0.01–0.37), P = 0.001); LA longitudinal diameter <57 mm (RR 0.33 (0.13–0.82), P = 0.016); and absence of LV hypertrophy (RR 0.15 (0.04–0.63), P = 0.01). Conclusions: Shorter AF episodes, smaller LA longitudinal diameter, and absence of LV hypertrophy are independent predictors of noninducibility of sustained AF after PVI. [ABSTRACT FROM AUTHOR]

FAUCHIER, L.et al.: Potential Cost Savings by Telemedicine-Assisted Long-Term Care of Implantable Cardioverter Defibrillator Recipients. Home monitoring (HM) of cardioverter defibrillators (ICD) with its automated wireless remote data access, may decrease the rate of patient visits. This study examined the potential cost savings for the long-term care of ICD assisted by HM. A French database including 502 patients from 6 university hospitals was used. Costs of conventional follow-up (FU) of ICD were calculated without, and compared with the expected cost of FU with HM. Calculations included number of visits, including physician's fees, electrocardiograms, and specific ICD surveillance, and transportation costs. The mean distance between home and institutions performing follow-ups was 69± 57 km. For each visit, a mean overall cost of$215 was calculated, including$121 for transportation and$94 for medical services. HM may obviate up to 2 visits per year. Over the 5 years of expected life of the device, the decrease in costs for FU visits was estimated at$2,149. With an additional cost of$1,200 for the HM system, saving began after a mean FU of 33.5 months. The time to onset of cost saving by HM ranged between 17.4 months for patients living>150 km from the medical facility to 52.2 months for those living<50 km away. It is concluded that the HM may considerably reduce the overall costs of ICD FU by saving on transportation cost, particularly when the distance between home and medical facility is>100 km.(PACE 2005; 28:S255–S259) [ABSTRACT FROM AUTHOR]

Objectives: We sought to evaluate the relationship between hemodynamic and ventricular dyssynchrony parameters in patients undergoing simultaneous and sequential biventricular pacing (BVP). Background: Various echocardiographic parameters of ventricular dyssynchrony have been proposed to screen and optimize BVP therapy. Methods: Forty-one patients with heart failure undergoing BVP implantation were studied. Echocardiography coupled with tissue tracking and pulsed Doppler tissue imaging (DTI) was performed before and after BVP implantation and after three months of optimized BVP. Indexes of inter- or intraventricular dyssynchrony were correlated with hemodynamic changes during simultaneous and sequential BVP (10 intervals of right ventricular [RV] or left ventricular [LV] pre-excitation). Results: Variations in intra-LV delaypeak, intra-LV delayonset, and index of LV dyssynchrony measured by pulsed DTI were highly correlated with those of cardiac output (r = −0.67, r = −0.64, and r = −0.67, respectively; p < 0.001) and mitral regurgitation (r = 0.68, r = 0.63, and r = 0.68, respectively; p < 0.001), whereas variations in the extent of myocardium displaying delayed longitudinal contraction (r = −0.48 and r = 0.51, respectively; p < 0.05) and the variations in septal-to-posterior wall motion delay (r = −0.41, p < 0.05 and r = 0.24, p = NS, respectively) were less correlated. The changes in interventricular dyssynchrony were not significantly correlated (p = NS). Compared with simultaneous BVP, individually optimized sequential BVP significantly increased cardiac output (p < 0.01), decreased mitral regurgitation (p < 0.05), and improved all parameters of intra-LV dyssynchrony (p < 0.01). At three months, a significant reverse mechanical LV remodeling was observed with significantly decreased LV volumes (p < 0.01) associated with an increased LV ejection fraction (p = 0.035). Conclusions: Specific echocardiographic measurements of ventricular dyssynchrony are highly correlated with hemodynamic changes and may be a useful adjunct in the selection and optimization of BVP. Individually optimized sequential BVP provided a significant early hemodynamic improvement compared with simultaneous BVP. [Copyright &y& Elsevier]

Biventricular and LV Pacing Comparison. Introduction:We conducted an acute echocardiographic study comparing hemodynamic and ventricular dyssynchrony parameters during left ventricular pacing (LVP) and biventricular pacing (BVP). We sought to clarify the mechanisms responsible for similar hemodynamic improvement despite differences in electrical activation.Methods and Results:Thirty-three patients underwent echocardiography prior to implantation with a multisite pacing device (spontaneous rhythm[SR]) and 2 days after implantation (BVP and LVP). Interventricular dyssynchrony (pulsed-wave Doppler), extent of myocardium displaying delayed longitudinal contraction (%DLC; tissue tracking), and index of LV dyssynchrony (pulsed-wave tissue Doppler imaging) were assessed. Compared to SR, BVP and LVP caused similar significant improvement of cardiac output (LVP: 3.2± 0.5, BVP: 3.1± 0.7, SR: 2.3± 0.6 L/min; P<0.01) and mitral regurgitation (LVP: 25.1± 10, BVP: 24.7± 11, baseline: 37.9± 14% jet area/left atria area; P<0.01). LVP resulted in a smaller index of LV dyssynchrony than BVP (29± 10 vs 34± 14; P<0.05). However, LVP exhibited a longer aortic preejection delay (220± 34 vs 186± 28 msec; P<0.01), longer LV electromechanical delays (244.5± 39 vs 209.5± 47 msec; P<0.05), greater interventricular dyssynchrony (56.6± 18 vs 31.4± 18; P<0.01), and higher%DLC (40.1± 08 vs 30.3± 09; P<0.05), leading to shorter LV filling time (387± 54 vs 348± 44 msec; P<0.05) compared to BVP.Conclusion:Although LVP and BVP provide similar hemodynamic improvement, LVP results in more homogeneous but substantially delayed LV contraction, leading to shortened filling time and less reduction in postsystolic contraction. These data may influence the choice of individual optimal pacing configuration.(J Cardiovasc Electrophysiol, Vol. 15, pp. 1-6, December 2004) [ABSTRACT FROM AUTHOR]

Unlabelled: We sought to assess right, left and biventricular pacing effects on myocardial function by using pulsed-Doppler tissue imaging (DTI) and automated border detection (ABD) techniques which provide electromechanical delay (EMD) assessment of the different left ventricular walls. Methods: 15 patients (67+/-7 years) with drug-resistant primitive dilated cardiomyopathy and QRS> or =140 ms received a pacemaker for multisite ventricular pacing. Echocardiography was performed after 1 month of biventricular pacing (BVP). Echocardiographic measurements were recorded during spontaneous rhythm (SpR), right ventricular pacing (RVP), left ventricular pacing (LVP) and BVP. Results: LV ejection fraction was statistically similar between the four rhythms. BVP showed a significant EMD decrease for the lateral LV wall vs. SpR, RVP and even LVP. LVP resulted in significantly longer aortic pre-ejection time vs. BVP while the EMD temporal dispersion (time between the shortest regional EMD and the longest one) was similar in the two modes. Conclusions: BVP and LVP substantially reduce the EMD temporal dispersion of the four LV walls, but with a longer aortic pre-ejection time for LVP. In RVP, LVP and BVP, the septal LV wall is always activated later than during SpR. BVP and LVP are associated with a mitral regurgitation reduction. [ABSTRACT FROM AUTHOR]

GARRIGUE, S., et al.: Sleep Apnea: A New Indication for Cardiac Pacing? In the general adult population, prevalence of sleep apnea syndrome reaches 4% in men and 2% in women. Continuous positive airway pressure is the most efficient treatment. At the present time, although severe atrial bradycardias could occur during sleep apnea episodes, cardiac pacing has not been demonstrated as an efficient treatment for those bradycardias. Treating sleep apnea generally reduces the number of bradyarrhythmias. However, recent studies reported a beneficial effect of atrial pacing on the sleep apnea burden. The mechanisms rely on two phenomena: first to counteract nocturnal hypervagotonia, and second to treat heart failure. By increasing the heart rate, cardiac output improves, which mitigates pulmonary subedema. Consequently, stimulation of the pulmonary afferent vagal fibers is diminished, which reduces central sleep apnea incidence. During nocturnal hypervagotonia, snoring and obstructive apnea episodes are increased, mainly due to an excessive muscular relaxation of the upper airway area inducing cyclical substantial decreases in the airway caliper. In patients with a low heart rate, atrial pacing can counteract hypervagotonia by enhancing the sympathetic tone and modifying the degree of vigilance. Accordingly, in the near future, sleep apnea treatment might potentially rely on atrial pacing in bradycardic patients with hypervagotonia (with or without heart failure). The role of the physician would then be not only to diagnose sleep apnea, but also to identify potential responders to cardiac pacing. (PACE 2004; 27:204–211) [ABSTRACT FROM AUTHOR]

: ObjectivesWe sought to assess the electromechanical parameters, using tissue Doppler echocardiography, as potential independent predictors of heart failure (HF) worsening.: BackgroundVentricular conduction disorders worsen the prognosis for HF patients. However, the relationships between the QRS width and morphology, hemodynamic parameters, and presence and magnitude of intra-left ventricular (LV) and inter-ventricular (V) asynchrony have not been well clarified.: MethodsA total of 104 patients with an LV ejection fraction (EF) ≤45% and stabilized HF, without myocardial infarction (MI), underwent echocardiography coupled with tissue Doppler imaging and were followed for one year. The protocol analyzed the incidence of worsening HF (hospitalization for cardiac decompensation). Inter-V and regional electromechanical delays for the anterior, septal, inferior, and lateral LV walls were correlated with the QRS morphology and duration. The intra-LV and inter-V asynchrony values of these patients were compared with those of healthy subjects matched by gender and age criteria to determine the respective normal ranges.: ResultsThe presence of intra-LV (but not inter-V) asynchrony was identified as an independent predictor of severe cardiac events (hazard ratio 3.39, p < 0.0001), independent of the LVEF and QRS width. Of patients with a QRS width <120 ms (55%; n = 57), 56% presented with major intra-LV asynchrony and 12% with inter-V asynchrony. Intra-LV asynchrony was observed in 84% of left bundle branch block patients, but also in 83% of right bundle branch block patients (p = NS). There was a poor correlation between the QRS width and intra-LV or inter-V asynchrony (r = 0.36, p = NS and r = 0.43, p = 0.05, respectively).: ConclusionsIn HF patients without MI, patients with intra-LV asynchrony are those with a significantly higher risk of cardiac events, independent of the QRS width and LVEF. Accordingly, such patients should be more actively identified for early intensive treatment and survey. [Copyright &y& Elsevier]

Presents a study which examined the effects of various combinations of pacing sites on the activation pattern of both ventricles during ischemia and identified specific precipitating factors of ventricular arrhythmia. Methods; Results and discussion.

Presents a study which determined the radiation exposure to patient and medical staff during atrial fibrillation compared with that measured during ablation of other arrhythmias in the same laboratory. Methods; Results and discussion; Conclusion.

: ObjectivesThis study evaluated the use of ectopic P-wave morphology to localize pulmonary vein (PV) and non-PV sources of atrial ectopics in patients with paroxysmal atrial fibrillation (PAF).: BackgroundThe vectorial information embodied in the morphology of ectopic P waves is concealed by overlying T waves.: MethodsThe P-wave morphology of 56 ectopics was prospectively analyzed in 44 patients with PAF (age, 52 ± 12 years; 36 male) by subtracting the adjacent QRST from the QRST-ectopic P-wave complex using custom-designed software. Subtraction fidelity was validated in 15 other patients (55 ± 19 years, 11 male) by comparing drive beats with simulated ectopics (S2 from the same site) unmasked by subtracting overlying QRST. An algorithm combined with PV pacemaps was used to predict PV sources. Subtracted ectopic P-wave morphologies after PV disconnection were compared with PV and non-PV site pacemaps. Localization was confirmed by mapping and successful ablation.: ResultsA ≥10-lead electrocardiogram (ECG) match was observed in 92% of 644 simulated ectopics (coupling intervals: 190 to 520 ms). In PAF patients, 37 spontaneous ectopics originated from the PV, while 19 were noted after PV disconnection. Using the P-wave algorithm alone, correct prediction of PV origin was achieved in 30/37 ectopics (81%). Combination with PV pacemaps allowed correct prediction in 34/37 (92%). After PV disconnection, ECG localization predicted successful ablation sites in 16/19 (84%).: ConclusionsComparison of subtracted ectopic P waves with a pacemap catalogue provides a simple and accurate 12-lead ECG-based method for localization, which can facilitate ablation of arrhythmia triggers irrespective of origin from the PV or elsewhere. [Copyright &y& Elsevier]

Compares the effects of biventricular pacing on regional ventricular electromechanic delay and hemodynamics in patients with complete right bundle branch block and drug-resistant heart failure. Likelihood that only patients with a right bundle branch block associated with a major left intraventricular asynchrony detected echocardiographically will respond to pacing therapy.

In patients with a wide QRS, drug-resistant heart failure, and a coronary sinus that is unsuitable for transvenous biventricular pacing (BVP), a transseptal approach from the right to left atrium can allow endocardial left ventricular (LV) pacing (with permanent anticoagulant therapy) instead of epicardial pacing via the coronary sinus branches. We sought to compare the effects of endocardial pacing with those of epicardial LV pacing on regional LV electromechanical delay (EMD) and contractility. Twenty-three patients (68 +/- 8 years) with severe heart failure and QRS > or =130 ms received a pacemaker for BVP. Fifteen patients underwent epicardial LV pacing, and 8 underwent endocardial LV pacing because of an unsuitable coronary sinus. All LV leads were placed at the anterolateral LV wall. Six months after implant, echocardiography and Doppler tissue imaging were performed. LV wall velocities and regional EMDs (time interval between the onset of the QRS and local ventricular systolic motion) were calculated for the 4 LV walls and compared for each patient between right ventricular (RV) and BVP. The amplitude of regional LV contractility was also assessed. Epicardial BVP reduced the septal wall EMD by 11% versus RV pacing (p = 0.05) and the lateral wall EMD by 41% versus RV pacing (p <0.01). With endocardial BVP, the septal and lateral EMDs were 21.3% and 54%, respectively (p <0.01, compared with epicardial BVP). The mitral time-velocity integral increased by 40% with endocardial BVP versus 2% with epicardial BVP (p <0.01). The amplitude of the lateral LV wall systolic motion increased by 14% with epicardial BVP versus 31% with endocardial BVP (p = 0.01). This resulted in a LV shortening fraction increase of 25% in patients with endocardial BVP (p = 0.05). However, all patients were clinically improved at the end of follow-up. Thus, in heart failure patients with BVP, endocardial BVP provides more homogenous intraventricular resynchronization than epicardial BVP and is associated with better LV filling and systolic performance. [ABSTRACT FROM AUTHOR]

Explores the application of curative treatment of atrial fibrillation (AF) by catheter-based ablation. Efficacy of linear ablation for AF; Details on catheter ablation of focally initiated AF; Characteristics of the surface electrocardiogram produced by very fast and irregular focal atrial tachycardia.

Reliability and Reproducibility of QRS Duration. Background: A QRS >120 ms remains the recommended criterion for the selection of cardiac resynchronization therapy (CRT) candidates. However, the reproducibility of this measurement has not been studied thoroughly. Methods: QRS duration was measured by 3 experienced cardiologists and by automatic measurement on 228 electrocardiograms (ECGs) randomly collected from 188 subjects, including neonates, healthy adults, patients with complete and incomplete bundle branch block, and CRT candidates. All ECGs were recorded at a 25 mm/s sweep speed. Forty recordings were duplicated and 50 ECGs were recorded at both 25 and 50 mm/s. Results: Significant interobserver differences (P < 0.001) were found between each combination of paired observers, with an up to 50-ms absolute variability between cardiologists and low concordance with computerized measurements. Intraobserver absolute variability was also significant (P < 0.01) for the 3 observers. These significant differences persisted (P < 0.01) when focusing our interest on the ECGs in the 100–140 ms range (defined as at least one out of the 4 measures in this range). Considering the 120 ms limit, 22 (27.5%) ECGs were differently classified by at least one of the cardiologists. We observed similar interobserver differences between each combination of paired observers with a 50 mm/s sweep speed. Conclusion: Manual QRS duration measurements were associated with significant inter- and intraobserver variability and low concordance with computerized measurements. The measurement of QRS is, therefore, operator-dependent and a reevaluation of the measurement methods may be essential to develop clinical and investigative standards. (J Cardiovasc Electrophysiol, Vol. 21, pp. 890-892, August 2010) [ABSTRACT FROM AUTHOR]

Radioprotection for Cardiac Device Implant. Introduction: Pacemaker implants are associated with a high cumulative exposure of the operators to radiation. Standard radiation protection with lead aprons is incomplete and the cause of spine disorders. A radiation protection cabin offers complete protection by surrounding the operator, without requiring a lead apron. Methods: We randomly and evenly assigned 60 patients undergoing implantations of permanent pacemakers or cardioverter defibrillators (ICD) with (a) a radiation protection cabin (cabin group, n = 30) versus (b) standard protection with a 0.5 mm lead-equivalent apron (control group, n = 30). Radiation exposure was measured using personal electronic dosimeters placed on the thorax, back, and head of the operator. Results: The patient, procedural, and device characteristics of the 2 study groups were similar. All procedures in the cabin group were performed as planned without increase in duration or complication rate compared with the control group. The mean radiation dose to the head, normalized for fluoroscopy duration, was significantly lower in the cabin (0.040 ± 0.032 μSv/min) than in the control (1.138 ± 0.560 μSv/min) group (p < 0.0001). The radiation doses to the thorax (0.043 ± 0.027 vs 0.041 ± 0.040 μSv/min) and back (0.038 ± 0.029 vs 0.033 ± 0.018 μSv/min) in the cabin versus control group (under the apron) were similar. Conclusions: The use of a radiation protection cabin markedly decreased the exposure of the operator to radiation, and eliminated the need to wear a lead apron, without increasing the procedural time or complication rate during implantation of pacemaker and ICD. (J Cardiovasc Electrophysiol, Vol. 21, pp. 428–430, April 2010) [ABSTRACT FROM AUTHOR]

The article discusses the mechanism of the medical case of a 52-year-old female with Brugada syndrome. Details related to the episodes of irregular electrical activity of the implanted cardioverter-defibrillator are presented. The case illustrates the consequences of lead-to-lead interaction which supports the need to remove the previous leads at the time of reimplantation.

A patient with chronic heart failure and chronic respiratory failure (CRF) underwent ambulatory polysomnography at home. She was found dead on the morning after the recording. The tracings confirmed severe sleep apnea syndrome. After 8 h of incessant Cheyne-Stokes respiration during sleep, respiratory arrest occurred, followed 7 min later by asystole. This report illustrates a case of respiratory drive failure during sleep as the mode of death in a patient with heart failure, sleep apnea syndrome, and CRF. [ABSTRACT FROM AUTHOR]

Background: Many patients with sleep apnea syndrome have nocturnal bradycardia, paroxysmal tachyarrhythmias, or both, which can be prevented by permanent atrial pacing. We evaluated the effect of using cardiac pacing to increase the heart rate during sleep in patients with sleep apnea syndrome. Methods: We studied 15 patients (11 men and 4 women; mean [±SD] age, 69±9 years) with central or obstructive sleep apnea who had received permanent atrial-synchronous ventricular pacemakers for symptomatic sinus bradycardia. All patients underwent three polysomnographic evaluations on consecutive nights, the first night for base-line evaluation and then, in random order, one night in spontaneous rhythm and one in dual-chamber pacing mode with atrial overdrive (basic rate, 15 beats per minute faster than the mean nocturnal sinus rate). The total duration and number of episodes of central or obstructive sleep apnea or hypopnea were analyzed and compared. Results: The mean 24-hour sinus rate during spontaneous rhythm was 57±5 beats per minute at base line, as compared with 72±3 beats per minute with atrial overdrive pacing (P<0.001). The total duration of sleep was 321±49 minutes in spontaneous rhythm, as compared with 331±46 minutes with atrial overdrive pacing (P=0.48). The hypopnea index (the total number of episodes of hypopnea divided by the number of hours of sleep) was reduced from 9±4 in spontaneous rhythm to 3±3 with atrial overdrive pacing (P<0.001). For both apnea and hypopnea, the value for the index was 28±22 in spontaneous rhythm, as compared with 11±14 with atrial overdrive pacing (P<0.001). Conclusions: In patients with sleep apnea syndrome, atrial overdrive pacing significantly reduces the number of episodes of central or obstructive sleep apnea without reducing the total sleep time. (N Engl J Med 2002;346:404-12.) [ABSTRACT FROM AUTHOR]