Po-02-010 crt could not modify the arrhythmic substrate in patients with previous ventricular tachycardia/fibrillation

Patients with low cardiac function are at high risk for ventricular arrhythmia (VA). Previous studies showed that cardiac resynchronization therapy (CRT) improved left ventricular remodeling and CRT responder had lower risk of VA than non-responder. However, little is known about the risk of VA among the CRT responder with or without history of VA. The purpose of this study is to investigate the association between VA risk and CRT response among the patients with or without history of VA. Among our cohort of 497 consecutive CRT patients, we retrospectively investigated 351 patients, which included primary and secondary prevention of VA. Exclusion criteria was hemodialysis, date deficit of left ventricular ejection fraction or ventricular volume. VA was defined as lasted ≥ 30s or treated by anti-tachycardia pacing or shock. CRT responders defined as ≥ 15% decrease of in left ventricular end-systolic volume and increase left ventricular ejection fraction ≥ 10% after CRT implantation. Two hundred and forty patients were CRT responder (68.4%), and 70 patients were indication for secondary prevention (19.9%). During a follow-up of 901 days (inter quartile range: 365-1737) 93 patients had VA events (CRT responder: 55pts, CRT non-responder: 38pts). Kaplan-Meier analysis showed the responder had lower risk of VA than the non-responder among all patients (log rank p=0.003) and patients for primary prevention (log rank p=0.004), though there was no significant difference among the patient for secondary prevention (log rank p=0.695). In addition, multivariate analysis showed that responder was independent predictor of VA among the patient for primary prevention (hazard ratio 0.50; 95% confidence interval 0.29-0.84, p=0.009), though responder was not predictor of VA among the patient for secondary prevention (p=0.83) The patients for secondary prevention remain at high risk of VA even among CRT responders. CRT response could not reduce VA substrate.