Improvement of P wave dispersion after cardiac resynchronization therapy for heart failure

Objective: The purpose of this study is to investigate the effect of cardiac resynchronization therapy (CRT) on P wave maximum duration (PWM) and P wave dispersion (PWD) in patients with advanced heart failure. Methods: Forty-six patients (33 men; mean age, 60 +/- 11 years) with CRT were enrolled in the present study. PWM and PWD were measured using 12-lead surface electrocardiography (ECG) at a paper speed of 50 mm/s and 20 mm/mV Serial ECG, echocardiography, clinical assessment, and device interrogations were performed at baseline and 3 months after CRT. Results: After 3 months of follow-up, PWM and PWD values were significantly decreased (129.6 +/- 11.3 to 120.7 +/- 10.7 milliseconds, P < .001; 42.6 +/- 8.0 to 32.3 +/- 10.1 milliseconds; P < .001, respectively). It showed a significant reduction in left atrial diameter (LAD) (46.5 +/- 5.2 to 44.9 +/- 5.6 mm, P = .021) and an improvement in left ventricular ejection fraction (LVEF) (29.0% +/- 7.5% to 36.2% +/- 8.0%, P < .001). The decrease of PWM and PWD was positively correlated with the reduction of LAD and negatively correlated with the improvement of LVEF. The reduction in atrial fibrillation burden was observed after 3 months of follow-up. Conclusions: Cardiac resynchronization therapy decreases PWM and PWD along with an improvement of LVEF and a reduction of LAD. Further studies are needed to evaluate the clinical implications of decrease of PWD on prevention of atrial fibrillation. (c) 2009 Elsevier Inc. All rights reserved.