Implications of ventricular arrhythmia after cardiac resynchronization therapy

BACKGROUND Conflicting data are available on whether ventricular arrhythmia (VA) or shock therapy increases mortality. Although cardiac resynchronization therapy (CRT) reduces the risk of VA, little is known about the prognostic value of VA among patients with CRT devices. OBJECTIVES The purpose of this study was to evaluate the implications of VA as a prognostic marker for CRT. METHODS We investigated 330 CRT patients within 1 year after CRT device implantation. The primary endpoint was the composite endpoint of all-cause death or hospitalization for heart failure. RESULTS Forty-three patients had VA events. These patients had a significantly higher risk of the primary endpoint, even among CRT responders (P = .009). Fast VA compared to slow VA was associated with an increased risk of the primary endpoint (hazard ratio [HR] 2.14; 95% confidence interval [CI] 1.06-4.34; P = .035). Shock therapy was not associated with a primary endpoint (shock therapy vs antitachycardia pacing: HR 1.49; 95% CI 0.73-3.03; P = .269). The patients with VA had a lower prevalence of response to CRT (23 [53%] vs 202 [70%]; P = .031) and longer left ventricular paced conduction time (174 +/- 23 ms vs 143 +/- 36 ms; P = .003) than the patients without VA. CONCLUSION VA occurrence within 1 year was related to paced electrical delay and poor response to CRT. VA could be associated with poor prognosis among CRT patients.