Three Year Outcome of Cardiac Resynchronization Therapy: A Single Center Evaluation

Geometrical characteristics of left ventricular dyssynchrony in advanced heart failure. Myocardial strain analysis by tagged MRI

The aims of this study were to quantify the geometrical differences in left ventricular (LV) dyssynchrony in patients with heart failure (HF) using cine-tagged MRI, and to investigate the relationship between dyssynchrony and major adverse cardiac events (MACE) in HF.In 67 patients with HF [mean LV ejection fraction (LVEF), 34%], cardiac MRI using a 3-Tesla scanner was performed. The dyssynchrony time between septal and lateral segments (SL-DT) and between basal and apical segments (BA-DT) was computed by cross-correlation analysis of the strain time-curves from the cine-tagged MRI. After receiving optimal medical treatment, all patients were followed-up for a mean period of 27 months. The primary endpoint was MACE that consisted of cardiac death or HF hospitalization or a left ventricular assist device due to refractory pump failure. Multivariate logistic regression analysis was performed to determine the ability of SL-DT, BA-DT, and HF biomarkers to predict MACE.Multivariate logistic regression analysis showed that the odds ratio to predict MACE was 0.935 for LVEF (P = 0.021), 1.016 for BA-DT (P = 0.026), and 0.971 for systolic blood pressure (P = 0.126).The results show that basal-apical dyssynchrony is an independent predictor of MACE in HF patients.

Ventricular arrhythmias in super-responders to cardiac resynchronization therapy

INTRODUCTION AND OBJECTIVES

Cardiac resynchronization therapy is associated with improved quality of life and reduced morbidity and mortality in patients with severe ventricular dysfunction and wide QRS. However, its role in the reduction of ventricular arrhythmias is more controversial.

METHODS

We compared the incidence of ventricular arrhythmias in patients who were undergoing cardiac resynchronization therapy with an implantable cardioverter-defibrillator in terms of the degree of echocardiographic response to resynchronization. Patients were classified in 3 subgroups;super-responders, responders, and nonresponders.

RESULTS

We included 196 patients who were followed up for a median 30.1 months [interquartile range, 18.0-55.1 months]. We recorded the presence of ventricular arrhythmias in 37 patients (18.8%); 3 patients (5.9%) in the super-responder group had ventricular arrhythmias vs 14 (22.2%) among the responders and 20 (24.4%) in the group of nonresponders (P = .025). In multivariate analysis, the only independent predictors of the appearance of ventricular arrhythmias were secondary-prevention device implantation (odds ratio = 4.04; 95% confidence interval, 1.52-10.75; P=.005), absence of echocardiographic super-response (odds ratio=3.81; 95% confidence interval, 1.04-13.93; P=043), QRS >160 ms (odds ratio=2.39; 95% confidence interval, 1.00-1.35; P=.049) and treatment with amiodarone (odds ratio=2.47; 95% confidence interval, 1.03-5.91; P=.041).

CONCLUSIONS

The patients classified as super-responders to cardiac resynchronization therapy had a significant reduction in incidence of ventricular arrhythmias by comparison with the other patients. Despite this, arrhythmic episodes do not completely disappear in this subgroup.

Relationship between impaired cardiac sympathetic activity and spatial dyssynchrony in patients with non-ischemic heart failure: assessment by MIBG scintigraphy and tagged MRI

BACKGROUND

Impairment of cardiac sympathetic activity has various detrimental effects on cardiac function. The purpose was to investigate the relationship between left ventricular (LV) dyssynchrony and cardiac sympathetic activity in non-ischemic heart failure (HF).

METHODS

Twenty-seven patients with non-ischemic HF were enrolled. Cardiac sympathetic activity was assessed by heart-to-mediastinum ratio (H/M ratio) on (123)I-Metaiodobenzylguanidine scintigraphy. LV dyssynchrony was assessed by cross-correlation analysis of time curves of myocardial circumferential strains delivered from cine-tagging MR images. Temporal dyssynchrony was defined as contraction delay between septal and lateral segments >110 milliseconds. Spatial dyssynchrony was defined as the negative value of the maximum correlation for the two strain time curves.

RESULTS

H/M ratio was significantly lower for patients with spatial dyssynchrony compared to patients without (1.8 ± 0.3 vs 2.1 ± 0.3, P < .05). There was no difference between patients with and without temporal dyssynchrony (2.0 ± 0.2 vs 2.0 ± 0.3). The incidence of spatial dyssynchrony was significantly higher in patients with H/M ratio <2.0 than those whose ratios were ≥2.0 (75% vs 20%, P = .001). There was no difference in the incidence of temporal dyssynchrony between the two groups (17% vs 20%).

CONCLUSION

Impairment of cardiac sympathetic activity was found to be associated with spatial dyssynchrony in patients with non-ischemic HF.

Cardiac resynchronization therapy: a breakthrough in heart failure management

Heart failure is now considered an epidemic. In patients with heart failure, electrical and mechanical dyssynchrony, evident primarily as prolongation of the QRS-complex on the surface electrocardiogram, is associated with detrimental effects on the cardiovascular system at several levels. In the past 10 years, studies have demonstrated that by stimulating both cardiac ventricles simultaneously, or almost simultaneously [cardiac resynchronization therapy (CRT)], the adverse effects of dyssynchrony can be overcome. Here, we provide a comprehensive overview of different aspects of CRT including the rationale behind and evidence for efficacy of the therapy. Issues with regard to gender effects and patient follow-up as well as a number of unresolved concerns will also be discussed.

The effects of aetiology on outcome in patients treated with cardiac resynchronization therapy in the CARE-HF trial

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 cm(3)). 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.

The impact of gender on survival amongst patients with implantable cardioverter defibrillators for primary prevention against sudden cardiac death

BACKGROUND

Implantable cardioverter defibrillators (ICDs) are a life-saving therapy for many patients with cardiovascular disease at increased risk of fatal dysrhythmias. As men comprise the majority of the study population (67-92%) in clinical trials, the benefit to women is unknown. We performed a meta-analysis of primary prevention trials to evaluate the impact of ICDs in men and women on death from any cause.

METHODS

Included trials met the following criteria: (i) randomized controlled trials versus standard of care, (ii) ICD used as primary prevention in a well-described protocol and (iii) data provided on risk of death from any cause for both male and female patients.

RESULTS

Five clinical trials were included in this meta-analysis. The risk of death from any cause was significantly reduced by 26% in male patients who received ICD therapy compared to control, hazard ratio (HR) 0.74 (95% CI 0.60-0.91) but not amongst female patients, HR 0.81 (95% CI 0.60-1.09). As the COMPANION trial evaluated the combination of biventricular pacemaker with ICD therapy we conducted a separate analysis without the inclusion of this study. Male patients receiving ICD therapy demonstrated a similar 24% reduction in risk of death from any cause, HR 0.76 (95% CI 0.58-0.99) whilst female patients demonstrated a reduction of only 12%, HR 0.88 (95% CI 0.63-1.22).

CONCLUSIONS

Unlike their male counterparts, females did not significantly benefit from ICD therapy and without concurrent biventricular pacing, appear only to achieve a nonsignificant 12% reduction in risk of death.