[Upgrading to resynchronization therapy in patients with heart failure after chronic right ventricular apical pacing].

ABSTRACT

OBJECTIVE: To investigate the clinical efficacy of cardiac resynchronization therapy (CRT) through biventricular pacing in chronically right ventricular apical paced patients with heart failure. METHODS: Ten chronically right ventricular apical paced patients with left ventricular ejection fraction (EF) ≤ 35% underwent CRT upgrading. And the follow-up period was over 12 months. Seven of them reported a significant improvement in their symptoms. Two patients died and one patient had no response. As compared with pre-CRT, CRT significantly improved NYHA classification, decreased left atrium diameter [(43 ± 5) mm vs (46 ± 7) mm], pulmonary arterial pressure [(42 ± 6) mm Hg vs (54 ± 13) mm Hg] and BNP [(184 ± 73) ng/L vs (545 ± 286) ng/L] (P < 0.05), improved left ventricular EF [(35 ± 5)% vs (32 ± 4)%]. Tissue Doppler imaging revealed the maximal difference of time to peak myocardial systolic contraction of 12 left ventricular segment shortened [(136 ± 28) ms vs (97 ± 18) ms], interventricular mechanical delay shortened [(52 ± 5) ms vs (31 ± 6) ms)] after upgrading. CONCLUSION: CRT upgrading from right ventricular apical pacing may improve left ventricular function in patients with heart failure.