Super-response to cardiac resynchronization therapy reduces appropriate implantable cardioverter defibrillator therapy.

Aims: To determine the frequency of implantable cardioverter defibrillator (ICD) therapy following cardiac resynchronization therapy (CRT-D) implantation in super and non-super responders and whether greater improvement in left ventricular (LV) function after CRT is associated with a reduced burden in ICD therapy. Methods and results: This is a two-centre, retrospective study between January 2002 and September 2011. Patients were classified as non-super responders and super-responders based on the post-CRT ejection fraction (EF) of < 50% and ≥50%, respectively. Of 629 recipients of CRT-D, 37 (5.9%) were super-responders. Implantable cardioverter defibrillator follow-up was available for a mean duration of 6.2 ± 2.7 years. The 5-year rate of antitachycardia pacing (ATP) in super-responders was significantly lower than in non-super responders (2.7% vs. 22.1%, P = 0.004). Super-responders also had a lower 5-year rate of appropriate ICD shock compared with non-super responders (2.7% vs. 14.3%, P = 0.03). On multivariable analysis, factors associated with appropriate ICD therapy (ICD shock/ATP) include male gender (hazard ratio, HR 1.97, 95% confidence interval, 95% CI 1.15-3.35), secondary prevention indication (HR 2.09, 95% CI 1.13-3.85), increased baseline LV end-systolic diameter (HR 1.03 per mm, 95% CI 1.01-1.06) and higher baseline EF (HR 1.03 per %, 95% CI 1.00-1.06) while super-responder status was highly protective (HR 0.13, 95% CI 0.02-0.91). Conclusion: Recipients of CRT-D that normalize their EF have very low rates of ventricular arrhythmias requiring appropriate ICD therapy compared with those that do not.

Predictors and outcomes of "super-response" to cardiac resynchronization therapy.

BACKGROUND: Cardiac resynchronization therapy (CRT) has been shown to improve heart failure (HF) symptoms and survival. We hypothesized that a greater improvement in left-ventricular ejection fraction (LVEF) after CRT is associated with greater survival benefit. METHODS AND RESULTS: In 693 patients across 2 international centers, the improvement in LVEF after CRT was determined. Patients were grouped as non-/modest-, moderate-, or super-responders to CRT, defined as an absolute change in LVEF of ≤5%, 6-15%, and >15%, respectively. Changes in New York Heart Association (NYHA) functional class and left ventricular end-diastolic dimension (LVEDD) were assessed for each group. There were 395 non-/modest-, 186 moderate-, and 112 super-responders. Super-responders were more likely to be female and to have nonischemic cardiomyopathy, lower creatinine, and lower pulmonary artery systolic pressure than non-/modest- and moderate-responders. Super-responders were also more likely to have lower LVEF than non-/modest-responders. There was no difference in NYHA functional class, mitral regurgitation grade, or tricuspid regurgitation grade between groups. Improvement in NYHA functional class (-0.9 ± 0.9 vs -0.4 ± 0.8 [P < .001] and -0.6 ± 0.8 [P = .02]) and LVEDD (-8.7 ± 9.9 mm vs -0.5 ± 5.0 and -2.4 ± 5.8 mm [P < .001 for both]) was greatest in super-responders. Kaplan-Meier survival analysis revealed that super-responders achieved better survival compared with non-/modest- (P < .001) and moderate-responders (P = .049). CONCLUSIONS: Improvement in HF symptoms and survival after CRT is proportionate to the degree of improvement in LV systolic function. Super-response is more likely in women, those with nonischemic substrate, and those with lower pulmonary artery systolic pressure.

Effects of atrioventricular conduction delay on the outcome of cardiac resynchronization therapy.

BACKGROUND AND PURPOSE: First-degree atrioventricular (AV) block in relation to the outcome of cardiac resynchronization therapy (CRT) has not been well examined. METHODS: Patients who received a CRT defibrillator or pacemaker between January 2002 and September 2010 at Mayo Clinic were classified into 2 groups: normal PR interval and prolonged PR interval. Standard sensed (100 milliseconds) and paced (130 milliseconds) AV delay was programmed after CRT. Clinical presentations and echocardiography were assessed before CRT and at a median of 6 months after CRT. RESULTS: The normal PR interval group (n=199) had greater improvements in heart failure functional class (mean [SD], 0.7 [0.8] vs 0.5 [0.9]; P=.03) and left ventricular ejection fraction (9.4% [12.4%] vs 5.9% [9.5%]; P=.007) than the prolonged PR group (n=204). CONCLUSION: Compared with prolonged PR interval, the presence of normal PR interval was associated with a greater improvement in heart failure.

Outcomes of cardiac resynchronization therapy in the elderly.

BACKGROUND: Octogenarians (>80 years) have been underrepresented in clinical trials of cardiac resynchronization therapy (CRT). OBJECTIVE: To determine the benefit of CRT with or without a defibrillator in older elderly patients. METHODS: We retrospectively studied consecutive patients who received CRT at our institution from 2002 through 2008. New York Heart Association (NYHA) class and echocardiographic parameters were assessed before and after CRT. Thirty-day complications after device implant were collected. Survival data were obtained from the national death and location database. Data were compared between those 80 years and younger and those older than 80 years. RESULTS: Of 728 patients identified, 90 (12.4%) were older than 80 years. After CRT, older and younger patients had similar improvements in NHYA class (P = 0.41), ejection fraction (P = 0.48), and mitral valve regurgitation (MR) severity (P = 0.42). In the older patients, defibrillator implantation was associated with comparable improvement in NYHA class, ejection fraction, and MR grade severity (P > 0.05), as in those without a defibrillator. Overall survival was worse in octogenarians than in the younger patients by Kaplan-Meier estimates (P = 0.001). Multivariate analysis showed similar survival between the younger and older subjects (hazard ratio, 1.23; 95% confidence interval, 0.83-1.84; P = 0.31). The observed complication rate in all study subjects was 12.2%, with no difference between the two age groups. CONCLUSION: Octogenarian patients who received CRT with or without a defibrillator for advanced heart failure had similar clinical benefits as younger patients. CRT should not be withheld from octogenarians meeting current selection guidelines.

Left ventricular lead position for cardiac resynchronization: a comprehensive cinegraphic, echocardiographic, clinical, and survival analysis.

AIMS: We sought to determine the clinical and survival outcomes of cardiac resynchronization therapy (CRT) associated with left ventricular (LV) lead location. The lateral left ventricle has been considered the optimal LV lead location for CRT. METHODS AND RESULTS: Left ventricular lead cinegrams taken in 30° right and left anterior oblique views were evaluated in 457 recipients of CRT with a pacemaker or a defibrillator from 1 January 2002 to 31 December 2008 in this retrospective study. Left ventricular lead placement was prioritized at implantation into posterolateral (PL), anterolateral (AL), middle cardiac, and anterointerventricular coronary veins. Using echocardiographic LV 16-segment analysis, we grouped the leads as anterior, AL, PL, and posterior locations. New York Heart Association (NYHA) class and echocardiography were assessed before and after CRT. Clinical and survival outcomes after CRT were compared among the four LV lead locations.  Patient baseline demographic characteristics were similar among these four groups. Improvement in NYHA class was significantly greater in the AL (P= 0.04) and PL (P= 0.03) locations than in the anterior location. There was a tendency for greater improvement in LV ejection fraction among the AL (P= 0.11) and PL (P= 0.08) locations than the anterior location. Kaplan-Meier survival estimate at 4 years varied for location: AL, 72%; anterior, 48%; PL, 62%; and posterior, 72% (P= 0.003). CONCLUSION: Cardiac resynchronization therapy recipients are profiting from all lead positions. However, LV lead placed in the AL and PL positions is more preferential for achieving optimal CRT benefit than leads placed in the anterior position.

Effects of tricuspid valve regurgitation on outcome in patients with cardiac resynchronization therapy.

Cardiac resynchronization therapy (CRT) has a symptomatic and survival benefit for patients with heart failure (HF), but the percentage of nonresponders remains relatively high. The aims of this study were to assess the clinical significance of baseline tricuspid regurgitation (TR) or worsening TR after implantation of a CRT device on the response to therapy. This is a multicenter retrospective analysis of prospectively collected databases that includes 689 consecutive patients who underwent implantation of CRT. The patients were divided into groups according to baseline TR grade and according to worsening TR within 15 months after device implantation. Outcome was assessed by clinical and echocardiographic response within 15 months and by estimated survival for a median interquartile range follow-up time of 3.3 years (1.6, 4.6). TR worsening after CRT implantation was documented in 104 patients (15%). These patients had worse clinical and echocardiographic response to CRT, but worsening of TR was not a significant predictor of mortality (p = 0.17). According to baseline echocardiogram, 620 patients (90%) had some degree of TR before CRT implant. Baseline TR was an independent predictor of worse survival (p <0.001), although these patients had significantly better clinical and echocardiographic response compared with patients without TR. In conclusion, worsening of TR after CRT implantation is a predictor of worse clinical and echocardiographic response but was not significantly associated with increased mortality. Baseline TR is associated with reduced survival despite better clinical and echocardiographic response after CRT implantation.