Left ventricular lead location and the risk of ventricular arrhythmias in the MADIT-CRT trial.

AIMS We aimed to evaluate the influence of left ventricular (LV) lead position on the risk of ventricular tachyarrhythmias in cardiac resynchronization therapy (CRT) patients. METHODS AND RESULTS Left ventricular (LV) lead position was evaluated by biplane coronary venograms and anterior/posterior, lateral chest X-rays in patients enrolled in the Multicenter Automatic Defibrillator Implantation Trial - Cardiac Resynchronization Therapy (MADIT-CRT). The LV lead location could be defined in 797 of 1089 patients (73%). The LV lead was placed at the LV apex in 110 (14%) patients, in the anterior position in 146 (18%), in the lateral position in 448 (56%), and in the posterior position in 93 (12%) patients. After adjustment for clinical covariates, lateral or posterior lead location was associated with significantly lower risk of ventricular tachycardia (VT)/ventricular fibrillation (VF) [hazard ratio (HR) = 0.57, 95% confidence interval (CI): 0.38-0.85; P = 0.006] when compared with an anterior lead location. Patients with anterior lead position had similar risk of VT/VF as patients with implantable cardioverter defibrillator (ICD)-only (HR = 1.04, 95% CI: 0.72-1.81; P = 0.837). There was no difference in the risk of mortality between posterior or lateral and anterior LV lead locations. CONCLUSION Cardiac resynchronization therapy with posterior or lateral LV lead position is associated with decreased risk of arrhythmic events in comparison with anterior lead location and ICD-only patients. There is no evidence for increased risk of VT/VF episodes associated with CRT.