Implantation Feasibility, Procedure‐Related Adverse Events and Lead Performance During 1‐Year Follow‐Up in Patients Undergoing Triple‐Site Cardiac Resynchronization Therapy: A Substudy of TRUST CRT Randomized Trial

INTRODUCTION: This substudy was to assess implantation feasibility and long-term safety of triple-site resynchronization therapy (CRT) in a series of consecutive patients included in a randomized trial. METHODS AND RESULTS: One hundred consecutive patients enrolled into Triple-Site Versus Standard Cardiac Resynchronization Therapy Randomized Trial were analyzed. Eligibility criteria included NYHA class III-IV, sinus rhythm, QRS ≥ 120 milliseconds, left ventricular ejection fraction ≤35%, and significant mechanical dyssynchrony. Patients were randomized in a 1:1 ratio to conventional or triple-site CRT with defibrillator-cardioverter. After 12 months of resynchronization 30% of patients with conventional resynchronization and 12.5% with triple-site CRT were in NYHA functional class III or IV (P < 0.05). Implantation of triple-site systems was significantly longer (median 125 minutes vs 96 minutes; P < 0.001), with higher fluoroscopic exposure, especially in patients with very enlarged left ventricle or pulmonary hypertension. Implantation success-rate was similar in the triple-site and conventional group (94% vs 98%; P = NS); however, additional techniques had to be used in a greater proportion of the triple-site patients (33.3% vs 16%; P < 0.05). Long-term lead performance tests revealed significantly higher pacing threshold and lower impedance in the triple-site group. The 1-year incidence of serious, CRT-related adverse events was similar in triple-site and conventional group (20.8% vs 30%; P = NS). CONCLUSIONS: Triple-site CRT is associated with more pronounced functional improvement than standard resynchronization. This form of pacing is equally safe and feasible as the conventional CRT. However, triple-site procedure is more time-consuming, associated with higher radiation exposure and the need to use additional techniques. Triple-site resynchronization is associated with less favorable electrical lead characteristics.