A. Zegard

Outcomes of Cardiac Resynchronization Therapy With or Without Defibrillation in Patients With Nonischemic Cardiomyopathy

BACKGROUNDnRecent 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.nnnOBJECTIVESnThe 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.nnnMETHODSnClinical events were quantified in patients with NICM who werexa0+MWF (nxa0=xa068) orxa0-MWF (nxa0=xa0184) who underwent cardiac magnetic resonance prior to CRT device implantation.nnnRESULTSnIn the total study population,xa0+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] forxa0+MWF and 4.6 years [interquartile range: 2.4 to 8.3 years] forxa0-MWF). In separate analyses ofxa0+MWF andxa0-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 inxa0+MWF but not inxa0-MWF.nnnCONCLUSIONSnIn patients with NICM, CRT-D was superior to CRT-P inxa0+MWF but notxa0-MWF. These findings havexa0implications for the choice of device therapy in patients with NICM.

Cardiac Resynchronization Therapy Using Quadripolar Versus Non‐Quadripolar Left Ventricular Leads Programmed to Biventricular Pacing With Single‐Site Left Ventricular Pacing: Impact on Survival and Heart Failure Hospitalization

Background In cardiac resynchronization therapy (CRT), quadripolar (QUAD) left ventricular (LV) leads are less prone to postoperative complications than non‐QUAD leads. Some studies have suggested better clinical outcomes. Methods and Results Clinical events were assessed in 847 patients after CRT‐pacing or CRT‐defibrillation using either QUAD (n=287) or non‐QUAD (n=560), programmed to single‐site site LV pacing. Over a follow‐up period of 3.2 years (median [interquartile range, 1.90–5.0]), QUAD was associated with a lower total mortality (adjusted hazard ratio [aHR]: 0.32, 95% confidence interval [CI], 0.20–0.52), cardiac mortality (aHR: 0.36, 95% CI, 0.20–0.65), and heart failure (HF) hospitalization (aHR: 0.62, 95% CI, 0.39–0.99), after adjustment for age, sex, New York Heart Association class, HF etiology, device type (CRT‐pacing or CRT‐defibrillation), comorbidities, atrial rhythm, medication, left ventricular ejection fraction, and creatinine. Death from pump failure was lower with QUAD (aHR: 0.33; 95% CI, 0.18–0.62), but no group differences emerged with respect to sudden cardiac death. There were no differences in implant‐related complications. Re‐interventions for LV displacement or phrenic nerve stimulation, which were lower with QUAD, predicted total mortality (aHR: 1.68, 95% CI, 1.11–2.54), cardiac mortality (aHR: 2.61, 95% CI, 1.66–4.11) and HF hospitalization (aHR: 2.09, 95% CI, 1.22–3.58). Conclusions CRT using QUAD, programmed to biventricular pacing with single‐site LV pacing, is associated with a lower total mortality, cardiac mortality, and HF hospitalization. These trends were observed for both CRT‐defibrillation and CRT‐pacing, after adjustment for HF cause and other confounders. Re‐intervention for LV lead displacement or phrenic nerve stimulation was associated with worse outcomes.

Clinical outcomes after upgrading from pacemakers to cardiac resynchronization therapy

Right ventricular pacing may lead to heart failure (HF). Upgrades from pacemakers to cardiac resynchronization therapy (CRT) were excluded from most randomized, controlled trials. We sought to determine the long‐term outcomes of upgrading from pacemakers to CRT with (CRT‐D) or without (CRT‐P) defibrillation in patients with no history of sustained ventricular arrhythmias.