Yat-Sun Chan

Left Ventricular Reverse Remodeling but Not Clinical Improvement Predicts Long-Term Survival After Cardiac Resynchronization Therapy

Background—In patients with severe heart failure and dilated cardiomyopathy, cardiac resynchronization therapy (CRT) improves left ventricular (LV) systolic function associated with LV reverse remodeling and favorable 1-year survival. However, it is unknown whether LV reverse remodeling translates into a better long-term prognosis and what extent of reverse remodeling is clinically relevant, which were investigated in this study. Methods and Results—Patients (n=141) with advanced heart failure (mean±SD age, 64±11 years; 73% men) who received CRT were followed up for a mean (±SD) of 695±491 days. The extent of reduction in LV end-systolic volume (LVESV) at 3 to 6 months relative to baseline was examined for its predictive value on long-term clinical outcome. The cutoff value for LV reverse remodeling in predicting mortality was derived from the receiver operating characteristic curve. Then the relation between potential predictors of mortality and heart failure hospitalizations were compared by Kaplan-Meier survival analysis, followed by Cox regression analysis. There were 22 (15.6%) deaths, mostly due to heart failure or sudden cardiac death. The receiver operating characteristic curve found that a reduction in LVESV of ≥9.5% had a sensitivity of 70% and specificity of 70% in predicting all-cause mortality and of 87% and 69%, respectively, for cardiovascular mortality. With this cutoff value, there were 87 (61.7%) responders to reverse remodeling. In Kaplan-Meier survival analysis, responders had significantly lower all-cause morality (6.9% versus 30.6%, log-rank &khgr;2=13.26, P=0.0003), cardiovascular mortality (2.3% versus 24.1%, log-rank &khgr;2=17.1, P<0.0001), and heart failure events (11.5% versus 33.3%, log-rank &khgr;2=8.71, P=0.0032) than nonresponders. In the Cox regression analysis model, the change in LVESV was the single most important predictor of all-cause (&bgr;=1.048, 95% confidence interval=1.019 to 1.078, P=0.001) and cardiovascular (&bgr;=1.072, 95% confidence interval=1.033 to 1.112, P<0.001) mortality. Clinical parameters were unable to predict any outcome event. Conclusions—A reduction in LVESV of 10% signifies clinically relevant reverse remodeling, which is a strong predictor of lower long-term mortality and heart failure events. This study suggests that assessing volumetric changes after an intervention in patients with heart failure provides information predictive of natural history outcomes.

Tissue Doppler velocity is superior to displacement and strain mapping in predicting left ventricular reverse remodelling response after cardiac resynchronisation therapy

Objective: To compare the values of three different forms of tissue Doppler imaging (TDI) processing in predicting left ventricular (LV) reverse remodelling—namely, tissue velocity, displacement and strain mapping. Design: Standard echocardiography with TDI was performed before and 3 months after cardiac resynchronisation therapy (CRT). Setting: University teaching hospital. Patients: 55 patients with heart failure who received CRT and were followed up for at least 3 months were recruited. Interventions: During off-line analysis, the time to peak systolic velocity in the ejection phase, time to peak positive displacement and time to peak negative strain were measured in the six basal, six mid-segmental model. Parameters of systolic asynchrony derived by velocity, displacement and strain mapping were correlated with percentage reduction in LV end systolic volume (LVESV) and absolute gain in ejection fraction (EF). Results: Among the three TDI processing technologies, all parameters of tissue velocity correlated with LV reverse remodelling (r  = −0.49 to r  =  −0.76, all p < 0.001), but the predictive value was strongest in models with 12 LV segments. For displacement mapping, only the two parameters that included 12 LV segments correlated modestly with reduction in LVESV (r  =  −0.36, p < 0.05) and gain in EF. However, none of the strain mapping parameters predicted a favourable echocardiographic response. The receiver operating characteristic (ROC) curve areas were higher for parameters of tissue velocity based on 12 LV segments (ROC areas 0.88 and 0.94) than the corresponding areas derived from displacement mapping (ROC areas 0.72 and 0.71). Conclusion: Tissue velocity parameters of systolic asynchrony are superior to those of displacement and strain mapping in predicting LV reverse remodelling response after CRT.

Comparison of Efficacy of Reverse Remodeling and Clinical Improvement for Relatively Narrow and Wide QRS Complexes After Cardiac Resynchronization Therapy for Heart Failure

Introduction: Cardiac resynchronization therapy (CRT) has been shown to reverse left ventricular (LV) remodeling and improve symptoms in heart failure patients with wide QRS complexes; however, its role in patients with mildly prolonged QRS complexes is unclear. This study investigated if CRT benefited patients with mildly prolonged QRS complexes >120 to 150 ms and explored if the severity of systolic asynchrony determined such a response.

Comparison of left ventricular reverse remodeling induced by cardiac contractility modulation and cardiac resynchronization therapy in heart failure patients with different QRS durations.

BACKGROUND Cardiac contractility modulation (CCM) is a new device-based therapy for advanced systolic heart failure with normal QRS duration and therefore not suitable for cardiac resynchronization therapy (CRT). Left ventricular (LV) reverse remodeling was reported in patients treated with CCM or CRT, however, the extent of response was not compared. METHODS This observational study consisted of three groups of patients with symptomatic heart failure and LV ejection fraction <35% despite optimal medical therapy. Group 1 included those received CCM with a QRS duration <120 ms (n=33), Group 2 included those received CRT with a QRS duration of 120-150 ms (n=43), and Group 3 included those received CRT with a QRS duration >150 ms (n=56). LV end-systolic volume (LVESV) was measured at baseline and 3 months later. RESULTS Age, gender, etiology of heart failure and baseline ejection fraction were comparable. A significant LV reverse remodeling was observed in each group. The degree of LVESV reduction was similar between Group 1 and Group 2 (-11.3 ± 1 1.8 vs. -13.6 ± 18.3%, p=0.833), however, it was greater in Group 3 (-25.0 ± 18.0%, both p<0.01). By using the reduction ≥ 15%, the responder rate was not different between Group 1 (39%) and Group 2 (42%), but significantly higher in Group 3 (68%) (χ(2)=9.514, p=0.009). CONCLUSION CCM exhibited a similar LV reverse remodeling response to CRT for patients with a mildly prolonged QRS, though the effect was less strong when compared to CRT for patients with a very wide QRS.

Diverse patterns of longitudinal and radial dyssynchrony in patients with advanced systolic heart failure

Background Little is known about the impact of QRS duration and aetiology of heart failure on the pattern of left ventricular long- and short-axis dyssynchrony. Objective To investigate the impact of QRS duration and aetiology of heart failure on the pattern of left ventricular long- and short-axis dyssynchrony using tissue Doppler imaging (TDI) and two-dimensional (2D) speckle tracking imaging. Methods 448 patients with heart failure (aged 65±12 years, 75% men) with ejection fraction ≤35% from two cardiac centres were examined for the occurrence of longitudinal dyssynchrony by TDI, and for radial dyssynchrony by 2D speckle tracking imaging. Region(s) of the latest mechanical contraction were also determined. Results Longitudinal dyssynchrony was identified in 263 (59%) patients and radial dyssynchrony in 185 (41%). 125 (28%) patients had both longitudinal and radial dyssynchrony, 138 (31%) had only longitudinal, 60 (13%) had only radial, and 124 (28%) had neither form of dyssynchrony. TDI showed that the single most delayed segment was the septal, lateral, anterior, inferior, anteroseptal and posterior wall in 12%, 27%, 12%, 19%, 7% and 13% of patients, respectively, while multisegmental delay occurred in 10% of patients. These figures were 10%, 8%, 5%, 10%, 12%, 14% and 41%, respectively, using 2D speckle tracking. When compared between patients with wide and narrow QRS complexes, both longitudinal (63% vs 53%) and radial (49% vs 36%) dyssynchrony parameters were more frequently positive in the wide QRS group defined by QRS duration ≥120 ms (both p<0.05). When compared between non-ischaemic and ischaemic patients, the prevalence of longitudinal dyssynchrony was comparable (61% vs 57%, p=0.467), while radial dyssynchrony was marginally more common in the non-ischaemic group (47% vs 37%, p=0.049). However, the distributions of the most delayed segment between the subgroups were similar when assessed by the same echocardiographic method. Conclusion In patients with advanced systolic heart failure, the patterns of longitudinal and radial dyssynchrony are heterogeneous, and mechanical dyssynchrony tends to be more prevalent in the wide QRS group and the non-ischaemic group.

Identification of Unusual Conditions after Atrial Septal Defect Repair by Systematic Transthoracic Echocardiographic Assessment

Background: There is a lack of echocardiographic studies to address the detection of atrial masses and abnormal venous connections in patients with secundum atrial septal defect (ASD) repair. This study sought to demonstrate that with proper technique, these unusual conditions could be diagnosed confidently by transthoracic echocardiography. Method: We performed a retrospective review of all repaired ASD patients of all ages with follow‐up echocardiography done at Beijing Anzhen Hospital from year 1999 to 2005. Clinical and echocardiographic features of patients with aforementioned conditions were evaluated. Results: Systematic echocardiographic protocol identified 11 patients with unusual conditions, in whom four patients had atrial masses (three atrial thrombi, one inflammatory pseudotumor) and seven patients had abnormal venous connections (two inadvertent diversion of inferior vena cava to left atrium, five previously unrecognized partial anomalous pulmonary venous connections). Conclusion: Atrial masses and abnormal venous connections could be diagnosed through a systematic echocardiographic approach in evaluating patients with ASD repair.