Causes of non-response to cardiac resynchronization therapy in heart failure patients with permanent atrial fibrillation]

To evaluate the long-term effects and analyze causes of non-response to cardiac resynchronization therapy (CRT) in heart failure (HF) patients with permanent atrial fibrillation (AF).Thirty-three patients with HF and AF [29 men, mean age (61 ± 10) years, NYHA class III or IV, left ventricular ejection fraction (LVEF) ≤ 35%, QRS ≥ 120 ms in 31 cases] underwent bi-ventricular pacing (n = 26) or bi-ventricular pacing and atrioventricular node ablation (AVN-ablation, n = 7) were included in this study. Non-response was defined: the increase of left ventricular ejection fraction (LVEF) was less than 15%. Patients were followed-up for 4 years.Six patients died during follow up. Non-responder to CRT was observed in 6 out of 27 survived patients (22.22%). Six out of 7 patients underwent AVN-ablation were in responder group and 1 in non-responder group. Comparing with responder group, the baseline LVEF was significantly higher (37% vs. 32%, P = 0.003), and the history of HF was significantly longer (6.3 years vs. 4.1 years, P = 0.039), pulmonary artery pressure was significantly higher (53 vs. 32 mm Hg, P = 0.027), bi-ventricular pacing percentage (BIVP%) was significantly lower (75.86% vs. 91.73%, P = 0.007) in non-responder group.Higher LVEF, longer HF history, higher pulmonary artery pressure and lower BIVP% are factors linked with non-responses to CRT in this patient cohort. CRT plus AVN-ablation is associated with high response rate to CRT in this patient cohort.