Outcomes of cardiac resynchronization therapy with or without defibrillation in patients with nonischemic cardiomyopathy

Background Recent studies have cast doubt on the benefit of cardiac resynchronization therapy (CRT) with defibrillation (CRT-D) versus pacing (CRT-P) for patients with nonischemic cardiomyopathy (NICM). Left ventricular myocardial scar portends poor clinical outcomes. Objectives The aim of this study was to determine whether CRT-D is superior to CRT-P in patients with NICM either with (+) or without (−) left ventricular midwall fibrosis (MWF), detected by cardiac magnetic resonance. Methods Clinical events were quantified in patients with NICM who were +MWF (n = 68) or −MWF (n = 184) who underwent cardiac magnetic resonance prior to CRT device implantation. Results In the total study population, +MWF emerged as an independent predictor of total mortality (adjusted hazard ratio [aHR]: 2.31; 95% confidence interval [CI]: 1.45 to 3.68), total mortality or heart failure hospitalization (aHR: 2.02; 95% CI: 1.32 to 3.09), total mortality or hospitalization for major adverse cardiac events (aHR: 2.02; 95% CI: 1.32 to 3.07), death from pump failure (aHR: 1.95; 95% CI: 1.11 to 3.41), and sudden cardiac death (aHR: 3.75; 95% CI: 1.26 to 11.2) over a maximum follow-up period of 14 years (median 3.8 years [interquartile range: 2.0 to 6.1 years] for +MWF and 4.6 years [interquartile range: 2.4 to 8.3 years] for −MWF). In separate analyses of +MWF and −MWF, total mortality (aHR: 0.23; 95% CI: 0.07 to 0.75), total mortality or heart failure hospitalization (aHR: 0.32; 95% CI: 0.12 to 0.82), and total mortality or hospitalization for major adverse cardiac events (aHR: 0.30; 95% CI: 0.12 to 0.78) were lower after CRT-D than after CRT-P in +MWF but not in −MWF. Conclusions In patients with NICM, CRT-D was superior to CRT-P in +MWF but not −MWF. These findings have implications for the choice of device therapy in patients with NICM

Long‐Term Outcomes of Cardiac Resynchronization Therapy Using Apical Versus Nonapical Left Ventricular Pacing

Background Experimental evidence indicates that left ventricular (LV) apical pacing is hemodynamically superior to nonapical LV pacing. Some studies have shown that an LV apical lead position is unfavorable in cardiac resynchronization therapy. We sought to determine whether an apical LV lead position influences cardiac mortality after cardiac resynchronization therapy. Methods and Results In this retrospective observational study, the primary end point of cardiac mortality was assessed in relation to longitudinal (basal, midventricular, or apical) and circumferential (anterior, lateral, or posterior) LV lead positions, as well as right ventricular (apical or septal), assigned using fluoroscopy. Lead positions were assessed in 1189 patients undergoing cardiac resynchronization therapy implantation over 15 years. After a median follow‐up of 6.0 years (interquartile range: 4.4–7.7 years), an apical LV lead position was associated with lower cardiac mortality than a nonapical position (adjusted hazard ratio: 0.74; 95% confidence interval, 0.56–0.99) after covariate adjustment. There were no differences in total mortality or heart failure hospitalization. Death from pump failure was lower with apical than nonapical positions (adjusted hazard ratio: 0.69; 95% confidence interval, 0.51–0.94). Compared with a basal position, an apical LV position was also associated with lower risk of sudden cardiac death (adjusted hazard ratio: 0.34; 95% confidence interval, 0.13–0.93). No differences emerged between circumferential LV lead positions or right ventricular positions with respect to any end point. Conclusions In recipients of cardiac resynchronization therapy, an apical LV lead position was associated with better long‐term cardiac survival than a nonapical position. This effect was due to a lower risk of pump failure and sudden cardiac death

Mechanical effects of left ventricular midwall fibrosis in non-ischemic cardiomyopathy

Background: Left ventricular (LV) mid-wall fibrosis (MWF), which occurs in about a quarter of patients with non-ischemic cardiomyopathy (NICM), is associated with high risk of pump failure. The mid LV wall is the site of circumferential myocardial fibers. We sought to determine the effect of MWF on LV myocardial mechanics. Methods: Patients with NICM (n = 116; age: 62.8 ± 13.2 years; 67 % male) underwent late gadolinium enhancement cardiovascular magnetic resonance (CMR) and were categorized according to the presence (+) or absence (-) of MWF. Feature tracking (FT) CMR was used to assess myocardial deformation. Results: Despite a similar LVEF (24.3 vs 27.5 %, p = 0.20), patients with MWF (32 [24 %]) had lower global circumferential strain (εcc: -6.6 % vs -9.4 %, P = 0.004), but similar longitudinal (εll: -7.6 % vs. -9.4 %, p = 0.053) and radial (εrr: 14.6 % vs. 17.8 % p = 0.18) strain. Compared with - MWF, + MWF was associated with reduced LV systolic, circumferential strain rate (-0.38 ± 0.1 vs -0.56 ± 0.3 s-1, p = 0.005) and peak LV twist (4.65 vs. 6.31°, p = 0.004), as well as rigid LV body rotation (64 % vs 28 %, P cc: 0.34 vs. 0.46 s-1; DSRll: 0.38 vs. 0.50s-1; DSRrr: -0.55 vs. -0.75 s-1; all

Left ventricular lead position, mechanical activation, and myocardial scar in relation to left ventricular reverse remodeling and clinical outcomes after cardiac resynchronization therapy: A feature-tracking and contrast-enhanced cardiovascular magnetic resonance study.

BACKGROUND Late mechanical activation (LMA) and viability in the left ventricular (LV) myocardium have been proposed as targets for LV pacing during cardiac resynchronization therapy (CRT). OBJECTIVE The purpose of this study was to determine whether an LV lead position over segments with LMA and no scar improves LV reverse remodeling (LVRR) and clinical outcomes after CRT. METHODS Feature-tracking and late gadolinium enhancement images were analyzed retrospectively in patients with heart failure (HF) (n = 89; mean age 66.8 ± 10.8 years; LV ejection fraction = 23.1% ± 9.9%) who underwent cardiovascular magnetic resonance (CMR) scanning before CRT implantation. Lead positions were classified as concordant (no scar and LMA [time to peak systolic circumferential strain]) or nonconcordant (scar and/or no LMA). RESULTS LVRR occurred in 68% and 24% of patients with concordant and nonconcordant LV lead positions, respectively (P < .001). Over a median of 4.4 years (range 0.1-8.7 years), LV lead concordance predicted cardiac mortality (adjusted odds ratio [aOR] 0.27; 95% confidence interval [CI] 0.12-0.62) and cardiac mortality or HF hospitalizations (aOR 0.26, 95% CI 0.12-0.58). "No scar" in the paced segment predicted cardiac mortality (aOR 0.24; 95% CI 0.11-0.52) and cardiac mortality or HF hospitalizations (adjusted aOR 0.24; 95% CI 0.12-0.49). CONCLUSION LV lead deployment over nonscarred LMA segments was associated with better LVRR and clinical outcomes after CRT. LVRR was primarily related to LMA, whereas events were primarily related to scar. These findings support the use of late gadolinium enhancement CMR and feature-tracking CMR in guiding LV lead deployment

The clinical outcome of cardiac resynchronization therapy in post-surgical valvular cardiomyopathy

Aims: Trials have shown that cardiac resynchronization therapy (CRT) is effective in patients with ‘non-ischaemic cardiomyopathy’. Patients with post-surgical valvular cardiomyopathy (PSVCM) have been excluded from such trials. We sought to compare the clinical outcome of CRT in patients with PSVCM, idiopathic dilated cardiomyopathy (IDCM), or ischaemic cardiomyopathy (ICM). Methods and results: Clinical events and response to CRT were quantified in 556 patients (PSVCM = 38; IDCM = 165; ICM = 353) over 4.52 years [median, inter-quartile range (IQR): 4.42]. Response to CRT was defined as survival for ≥1 year free of hospitalizations plus improvement by ≥1 NYHA class or ≥25% in 6-min walking distance. Cardiac resynchronization therapy was initiated at 5.86 years (median, IQR: 9.86) after aortic valve replacement (73.7%) or mitral valve replacement/repair (44.7%). Compared with PSVCM, IDCM was associated with a lower total mortality [hazards ratio, HR: 0.54 (95% confidence interval, CI 0.34–0.84)], cardiac mortality [HR: 0.43 (95% CI 0.26–0.70)], and total mortality or major adverse cardiovascular events [HR: 0.57 (95% CI 0.37–0.87)], independent of known confounders. Compared with PSVCM, ICM was associated with a similar risk of death from pump failure [HR: 0.83 (95% CI 0.50–1.37)] and IDCM was associated with a lower risk [HR: 0.46 (95% CI 0.26–0.82)]. Response to CRT was similar across the groups. Conclusions: Compared with IDCM, PSVCM was associated with a worse outcome after CRT. Outcomes from PSVCM were similar to ICM. These findings indicate that PSVCM behaves very differently to IDCM after CRT

Long-term follow-up of normal and structural heart ventricular tachycardia catheter ablation: real-world experience from a UK tertiary centre.

Background Ventricular tachycardia (VT) is associated with increased morbidity and mortality. There is growing evidence for the effectiveness of catheter ablation in improving outcomes in patients with recurrent VT. Consequently the threshold for referral for VT ablation has fallen over recent years, resulting in increased number of procedures. Objective To evaluate the effectiveness and safety of VT ablation in a real-world tertiary centre setting. Methods This is a prospective analysis of all VT ablation cases performed at University Hospital Coventry. Follow-up data were obtained from review of electronic medical records and patient interview. The primary endpoint for normal heart VT was death, cardiovascular hospitalisation and VT recurrence, and for structural heart VT was arrhythmic death, VT storm (>3 episodes within 24 hours) or appropriate shock. Results Forty-seven patients underwent 53 procedures from January 2012 to January 2018. The mean age ±SD was 57±15 years, 68% were male, 81% were Caucasian and 66% were elective cases. The aetiology of VT included normal heart (49%), ischaemic cardiomyopathy (ICM, 36%), dilated cardiomyopathy (9%), hypertrophic cardiomyopathy (4%) and valvular heart disease (2%). Procedural success occurred in 83%, with six major complications. After a median follow-up of 231 days (lower quartile 133, upper quartile 631), the primary outcome occurred in 28% of patients. There were two non-arrhythmic deaths (4%). At a median follow-up of 193 days (129-468), the primary outcome occurred in 19% of patients with ICM, while VT storm/appropriate shocks occurred in three patients (17%). Conclusions Our real-world registry confirms that VT ablation is safe, and is associated with high acute procedural success and long-term outcomes comparable with randomised controlled studies

Renal function and the long term clinical outcomes of cardiac resynchronization therapy with or without defibrillation

BACKGROUND AND AIMS: Patients with moderate-to-severe chronic kidney disease (CKD) are underrepresented in clinical trials of cardiac resynchronization therapy (CRT)-defibrillation (CRT-D) or CRT-pacing (CRT-P). We sought to determine whether outcomes after CRT-D are better than after CRT-P over a wide spectrum of CKD. METHODS AND RESULTS: Clinical events were quantified in relation to preimplant estimated glomerular filtration rate (eGFR) after CRT-D (n = 410 [39.2%]) or CRT-P (n = 636 [60.8%]) implantation. Over a follow-up period of 3.7 years (median, interquartile range: 2.1-5.7), the eGFR < 60 group (n = 598) had a higher risk of total mortality (adjusted hazard ratio [aHR]: 1.28; P = 0.017), total mortality or heart failure (HF) hospitalization (aHR: 1.32; P = 0.004), total mortality or hospitalization for major adverse cardiac events (MACEs, aHR: 1.34; P = 0.002), and cardiac mortality (aHR: 1.33; P = 0.036), compared to the eGFR ≥ 60 group (n = 448), after covariate adjustment. In analyses of CRT-D versus CRT-P, CRT-D was associated with a lower risk of total mortality (eGFR ≥ 60 HR: 0.65; P = 0.028; eGFR < 60 HR: 0.64, P = 0.002), total mortality or HF hospitalization (eGFR ≥ 60 aHR: 0.66; P = 0.021; eGFR < 60 aHR: 0.69, P = 0.007), total mortality or hospitalization for MACEs (eGFR ≥ 60 aHR: 0.70; P = 0.039; eGFR < 60 aHR: 0.69, P = 0.005), and cardiac mortality (eGFR ≥ 60 aHR: 0.60; P = 0.026; eGFR < 60 aHR: 0.55; P = 0.003). CONCLUSION: In CRT recipients, moderate CKD is associated with a higher mortality and morbidity compared to normal renal function or mild CKD. Despite less favorable absolute outcomes, patients with moderate CKD had better outcomes after CRT-D than after CRT-P