Triple-site biventricular pacing in patients undergoing cardiac resynchronization therapy: a feasibility study

AIMS: To evaluate implantation safety and efficiency of triple-site (double left-single right) cardiac resynchronization therapy (CRT) and to assess the outcome of this procedure. METHODS AND RESULTS: Twenty-six patients with New York Heart Association (NYHA) class III-IV, left ventricular ejection fraction (EF) < or = 35%, and QRS > or = 120 ms underwent triple-site CRT. Procedural course and complications were analysed. NYHA class, QRS duration, echocardiographic parameters, peak oxygen consumption (VO(2)max), and 6 min walking distance (6MWD) were assessed at baseline and after 3 months. Responders were defined by survival, by no re-hospitalization for heart failure, and by >10% EF, VO(2)max, and 6MWD increase. Implantation was successful in 22 patients (84.6%). Procedure duration (199.1 min) and fluoroscopy time (38.7 min) were higher than in standard procedures. Two clinically silent coronary sinus dissections occurred intra-operatively; one phrenic nerve stimulation and one pocket infection were observed during follow-up. After 3 months of CRT, a significant reduction (P < 0.05) of NYHA class, increment of VO(2)max, 6MWD, EF, and improvement of indices of dyssynchrony were observed. Response rate in the studied group was 95.4%. CONCLUSION: Triple-site resynchronization appears to be a safe and efficient treatment method, with high response rate. Further studies are needed to evaluate the role of this pacing mode in CRT.