[Incidence and causes of nonresponse to cardiac resynchronization therapy in patients with congestive heart failure]

To observe the incidence and explore the potential factors of nonresponse to cardiac resynchronization therapy(CRT)in patients with severe chronic congestive heart failure.

CRT was performed in 119 patients with NYHA function class III-IV and left ventricular ejection fraction ≤ 35% [96 men and 23 women, age (60.5 ± 11.3) years].

Seven patients died for different reasons between 1 - 6 months post CRT and clinical and echocardiographic (Echo) data at 6 months post CRT were analyzed from the remaining 112 patients. The incidence of nonresponse to CRT was 28.57%. Compared to the response group, complete right bundle branch block, longer course of congestive heart failure, higher pulmonary systolic pressure and serum creatinine level and non-optimal target vessels positioning of the left ventricle lead (the great cardiac vein and the middle cardiac vein) were the independent predictors for nonresponse after CRT (all P < 0.05). Compared with nonresponse group, the dosages of digoxin and diuretics used for heart failure were significantly reduced in response group (P < 0.01).

The incidence of nonresponse after CRT was 28.57% in this patient cohort. Higher pulmonary systolic pressure and serum creatinine level and non-optimal target vessels positioning of the left ventricle lead (the great cardiac vein and the middle cardiac vein) were the independent predictors for nonresponse after CRT.