Search

Background: This study was performed in both animals and human subjects to test whether different approaches to calculate untwisting rate may lead to different results in the assessment of left ventricular (LV) relaxation., Methods: In animal experiments, congestive heart failure was successfully induced in 8 adult dogs. Transthoracic echocardiography was performed with simultaneous LV pressure recording at baseline and the stage of heart failure. In the clinical study, 72 patients undergoing right-sided heart catheterization were studied by transthoracic echocardiography. LV twist was calculated as the difference between apical and basal rotations measured using two-dimensional speckle tracking. Untwisting rate was calculated using 3 different algorithms as the peak negative time derivative of twist (UR(max)) during early diastole, the slope of the linear regression of untwisting over time (UR(slope)), or the average untwisting over the isovolumic relaxation period (UR(mean))., Results: UR(max) significantly correlated with tau and -dP/dt in dogs (r=-0.81 and 0.77, respectively, both P < .001) and was reduced at the stage of heart failure (P < .01). In 55 patients (76%) with adequate image quality, only UR(max) among untwisting rates calculated by 3 different algorithms was significantly related to tau (r=-0.51, P < .001). UR(max) was significantly lower in patients with tau>/=48 ms than in patients with tau<48 ms (P=.004), most of whom had a depressed LV ejection fraction., Conclusion: UR(max) best reflects LV relaxation in comparison with the 2 other algorithms.

Background: Recent studies validated the measurement of left ventricular (LV) untwisting rate (UR) by speckle tracking echocardiography. A few reports suggest that it may provide additional noninvasive insight into LV diastolic function., Methods and Results: Simultaneous echocardiographic imaging and LV pressure measurements (7F Millar catheters) were performed in 8 adult dogs. Loading conditions were altered by caval occlusion, whereas lusitropic state was changed by dobutamine and esmolol infusion. Inferior vena cava occlusion at all experimental stages (baseline, dobutamine, esmolol) led to a significant decrease (P < or = 0.01) in LV end-systolic volume (ESV) and a significant increase in UR (P = 0.03). The best relation was observed between LV UR and ESV (r = -0.8, P < 0.001). The clinical study was conducted in 67 patients (age 57+/-17 years, 19 women) undergoing simultaneous right heart catheterization and echocardiographic imaging, with 20 healthy subjects as a control group. There were 34 patients with ejection fraction (EF) <50% (25+/-9%), and 33 patients with normal EF and diastolic dysfunction (64+/-7%). Patients with LV systolic dysfunction had a significantly lower UR (-55 omicron/s) in comparison with the control group (-89 omicron/s) and patients with normal EF (-104 omicron/s, P < 0.05), and the determinants of LV UR were twist, ESV, and tau (r2 = 0.83, P < 0.001). In patients with diastolic dysfunction and normal EF, twist and ESV were the independent predictors (r2 = 0.71, P < 0.001)., Conclusions: LV UR is reduced in patients with depressed EF, but not in those with diastolic dysfunction and normal EF, and is primarily determined by twist and ESV.

Background: Assessment of right ventricular (RV) function by echocardiography is challenging. Newer techniques such as tissue Doppler echocardiography and strain echocardiography may allow accurate and quantitative assessment of RV function. We sought to determine which echocardiographic variable or variables best correlated with RV ejection fraction (RVEF) by cardiac magnetic resonance., Methods: We performed conventional echocardiography, tissue Doppler echocardiography, strain echocardiography, and cardiac magnetic resonance on 53 individuals, of which 10 patients had arrhythmogenic RV dysplasia without pulmonary hypertension, and 43 were control subjects. RV fractional area change (FAC), Tei index, isovolumic acceleration, peak systolic velocity (S'), tissue displacement, systolic strain (Ss) rate, and Ss were measured., Results: RVEF, FAC, S', tissue displacement, isovolumic acceleration, Ss rate, and Ss were significantly lower in patients compared with control subjects (P < or = .05 in all) but not the Tei index (P = .07). Regression analysis revealed a significant correlation between S', tissue displacement, Ss rate, Ss, and FAC with RVEF (P < .05 for all) but not with isovolumic acceleration and Tei index (P = .13 and .39, respectively). Multivariate analysis demonstrated a persistent significant relationship between S' and FAC with RVEF (both P < .05). However, feasibility, and intraobserver and interobserver agreement, were substantially lower for FAC. A cut-off value of 8.8 cm/s for S' had sensitivity and specificity of 80% and 79% (area under the curve 0.87, P = .01), respectively, for prediction of RVEF less than 45%., Conclusion: Tissue Doppler echocardiographically derived S' best correlates with cardiac magnetic resonance-derived RVEF with high reproducibility and may facilitate simple and quantitative assessment of RV function.

Arrhythmogenic right ventricular dysplasia (ARVD) is a heritable cardiomyopathy characterized by the fibrofatty replacement of right ventricular (RV) myocardium leading to RV failure and arrhythmias. This study evaluated the potential utility of tissue Doppler echocardiography (TDE) and strain echocardiography (SE) to quantitatively assess RV function and their potential role in diagnosing ARVD. Images of 30 patients with ARVD (diagnosed by task force criteria) and 36 healthy controls were obtained. Peak systolic velocity, early diastolic velocity, displacement, strain rate, strain, outflow tract diameter, and fractional RV area change were measured in all subjects. Peak RV systolic velocity (6.4 +/- 2.2 vs 9 +/- 1.6 cm/s, p <0.0001), early diastolic velocity (-6.7 +/- 2.7 vs -9.4 +/- 2 cm/s, p <0.0001), displacement (13.7 +/- 5.8 vs 18.7 +/- 3.5 mm, p <0.0003), strain rate (-1 +/- 0.7 vs -2 +/- 1 s(-1), p = 0.002), and strain (-10 +/- 6% vs -28 +/- 11%, p = 0.001) were significantly lower in patients with ARVD compared with controls, respectively. Sensitivity and specificity, respectively, were 67% and 89% for systolic velocity, 77% and 71% for displacement, 73% and 87% for strain, 50% and 96% for strain rate, 53% and 93% for outflow tract diameter, and 47% and 83% for fractional area change. RV systolic velocity and displacement were significantly lower than in controls, even in the subset of patients with ARVD with apparently normal right ventricles by conventional echocardiography. Inter- and intraobserver agreement was high. In conclusion, TDE and SE enable the detection of ARVD via the quantification of RV function and may have potential clinical value in the assessment of patients with suspected ARVD. Peak RV systolic velocity <7.5 cm/s and peak RV strain <18% best identify patients with ARVD.

We investigated the influence of > or =70% luminal coronary artery stenosis on regional diastolic deformation at rest using 2-dimensional strain echocardiography. We prospectively imaged patients during/within 24 hours of coronary angiography. Longitudinal systolic (SRs), early (SRe), and late diastolic strain rates, systolic, early, and late diastolic strain and times to isovolumic relaxation and peak SRe were measured in the 3 major vascular territories. Regions subtended by > or =70% coronary stenosis were labeled ischemic. Ischemic regions were compared with the same region in patients without significant coronary stenosis. Of 61 enrolled patients (38 men), 39 had > or =70% coronary stenosis (1 vessel in 14, 2 vessels in 15, 3 vessels in 10), and 15 had normal coronary arteries. There were no significant differences between the normal and ischemic groups with regard to age (59 +/- 13 vs 64 +/- 10 years, p = 0.20), clinical variables (dyslipidemia, smoking, diabetes), systolic (130 +/- 26 vs 139 +/- 31 mm Hg, p = 0.38) or diastolic (72 +/- 13 vs 72 +/- 11 mm Hg, p = 0.81) blood pressure and ejection fraction (58 +/- 12% vs 56 +/- 11%, p = 0.66). SRs and SRe were significantly decreased in ischemic compared with normal regions in all vascular distributions. SRs and SRe together (values below cutoff) or SRe alone were the most specific (93%) and SRe or SRs below cutoff the most sensitive (93%) parameters for detecting ischemic regions. In conclusion, analysis of regional deformation by 2-dimensional strain echocardiography enables detection of significantly diseased coronary arteries at rest. Altered diastolic deformation at rest identifies regions subtended by > or =70% coronary stenosis with high specificity.

Background: Myocardial function is transmurally heterogeneous. Postsystolic work may functionally reflect ischemic but viable myocardium. We calculated systolic and postsystolic regional myocardial work index (RMWi) in subendocardial and subepicardial layers of myocardium supplied by a slowly occluding coronary artery., Methods: Progressive stenosis of the left anterior descending coronary artery lasting 11 +/- 5 days (end point) was induced in 10 dogs, and pressure-strain loops were obtained from subendocardial and subepicardial layers of apical and middle anterior segments by intracardiac ultrasound., Results: At baseline, the RMWi was significantly higher (P < .05) in the subendocardial layer. At the end point, there was no significant change in the RMWi in ischemic myocardium; however, the postsystolic RMWi was higher (P < .05) in the subendocardial layer and accompanied a decrease in subendocardial myocardial blood flow, although viability was largely maintained., Conclusion: A significant subendocardial postsystolic RMWi at rest suggests an impending ischemic injury in coronary artery disease when segmental function is still preserved.

Eur J Clin Invest 2010; 40 (11): 976-983 Background Hypertrophic cardiomyopathy (HCM) is a genetic paradigm of cardiac hypertrophy. Cardiac hypertrophy is a major determinant of risk of sudden death and morbidity in HCM. Treatment with statins reverses hypertrophy in animal models of HCM. Thus, statins may afford therapeutic benefits in HCM. Methods We performed a feasibility study with atorvastatin to gather the pre-requisite data for designing randomized efficacy studies. Results We screened 32 patients with HCM in 18 months. Twenty-one patients met the study criteria and consented to participate. The demographics and echocardiographic phenotype of those who did and those who did not participate were not significantly different. We treated the participants with escalating doses of atorvastatin (20, 40 and 80 mg day−1) for 2 years. We performed ECG and echocardiography and measured plasma lipids, liver enzymes, creatine kinase and B-type natriuretic peptide levels before and after 3, 6, 12 and 24 months of therapy. Fifteen, 12 and 11 patients completed 6, 12 and 24 months of therapy respectively. Six patients discontinued atorvastatin because of perceived lack of benefit. We stopped atorvastatin in 4 patients because of modest elevations in liver enzymes, creatine kinase or back pain. The characteristics of those who did or did not complete the study were not significantly different. The mean plasma low-density lipoprotein-cholesterol level was reduced by 55%. However, echocardiographic indices of cardiac hypertrophy and function remained unchanged. Conclusions The findings illustrated the challenges that will be encountered in designing efficacy studies to test the potential beneficial effects of atorvastatin in human HCM. [ABSTRACT FROM AUTHOR]

Objectives: We sought to determine the mechanisms linking dynamic obstruction and exercise tolerance in patients with hypertrophic obstructive cardiomyopathy (HOCM). Background: Patients with HOCM have reduced exercise tolerance. However, the association between dynamic obstruction and peak oxygen consumption (Vo 2max) is weak. Methods: We enrolled 25 patients with HOCM, 20 with hypertrophic cardiomyopathy (HCM), and 20 normal control patients. Two-dimensional, Doppler, strain, and left ventricular (LV) twist mechanics by speckle tracking echocardiography were obtained. The 25 HOCM patients had left heart catheterization, and 16 were re-examined after septal reduction. Results: Deformation measurements were the lowest in HOCM patients and increased (p < 0.05) after septal reduction. Twist and untwisting rate were not different between patients with HCM and control patients, but untwisting was significantly delayed in HCM patients and longest in HOCM patients. The delay related well with LV end-diastolic pressure (r = 0.76) and volume (r = −0.73), and Vo 2max (r = −0.75, all p < 0.01). After septal reduction, untwisting occurred earlier and accounted for the increase in end-diastolic volume (r = 0.65), and Vo 2max (r = 0.74, both p < 0.05). Conclusions: Dynamic obstruction leads to delayed untwisting in HOCM, which accounts well for the increased LV filling pressures, the reduced LV volumes, and Vo 2max. After septal reduction, untwisting occurs earlier and leads to an improvement in LV filling and exercise tolerance. [Copyright &y& Elsevier]

This study examined the feasibility of Doppler transesophageal echocardiography (TEE) to detect collateral flow to the myocardium supplied by the right coronary artery (RCA) in the inferior left ventricular wall. Forty-four patients who underwent elective coronary artery bypass grafting (CABG) were prospectively studied. Presence of collateral flow to the RCA was diagnosed on preoperative angiography using the Rentrop score and by intraoperative Doppler TEE. Agreement of the 2 methods was analyzed by calculating the κ coefficient. Collateral flow was present on preoperative angiography in 19 patients and absent in 25 patients. Intraoperative TEE detected collateral flow in the inferior wall in 15 patients (79%) with and 3 patients (12%) without angiographic collaterals, resulting in a κ coefficient for agreement of 0.67 (95% confidence interval 0.45 to 0.90). Baseline collateral flow disappeared after CABG in 12 of 14 patients with grafting of the RCA but persisted in all patients without such grafting. Physiologic flow in the inferior wall was detected by TEE in a total of 27 patients at baseline and in 38 patients after CABG (p = 0.0018); its peak velocity increased after surgery only in the subgroup of patients with grafting of the RCA. In conclusion, these findings indicate that Doppler TEE may detect collateral flow in the inferior left ventricular wall, and that there are typical changes in collateral and physiologic flow after CABG. [Copyright &y& Elsevier]

Arrhythmogenic right ventricular dysplasia (ARVD/C) is a genetic cardiomyopathy characterized by fibrous fatty replacement of the right ventricular (RV) myocardium, leading to progressive RV failure and ventricular arrhythmias in young athletes. This study evaluated whether transthoracic, real-time, 3-dimensional echocardiography (3DE) can adequately assess RV morphology and function in ARVD/C by comparing 3DE with cardiac magnetic resonance (CMR), the current reference standard. Three-dimensional echocardiography was prospectively performed in 58 patients (23 with ARVD/C, 20 first-degree relatives with no ARVD/C, 8 with idiopathic ventricular tachycardia with no ARVD/C, and 7 healthy volunteers). All patients, except 15 patients with ARVD/C with implanted defibrillators, also underwent CMR. Three-dimensional echocardiography and CMR-derived RV volumes and ejection fractions were obtained by offline data analysis by blinded, independent observers. The mean age of the study group was 37 ± 11 years (30 men). The feasibility of 3DE was high, and analyzable images were obtained in all subjects. Three-dimensional echocardiography revealed a wide variety of RV morphologic abnormalities in ARVD/C. There was a good correlation between 3DE and CMR for RV end-systolic volume (r = 0.72, p = 0.0001), RV end-diastolic volume (r = 0.50, p = 0.0001), and the RV ejection fraction (r = 0.88, p = 0.001). We found high intraobserver and moderate interobserver correlations for 3DE estimations of volumes and ejection fractions. In conclusion, 3DE measurements of RV volumes and ejection fractions closely correlate with CMR values and may be useful in the follow-up of patients with ARVD/C. [Copyright &y& Elsevier]