Factors for development of left ventricular dysfunction during long-term right ventricular apical pacing

Background It is known that prolonged QRS duration (QRSd) in a 12-lead ECG is associated with decreased left ventricular (LV) systolic function in patients with dilated cardiomyopathy. Development of LV systolic dysfunction and prolongation of paced QRSd are often observed in patients with permanent pacemakers (PPM). However, the significance of prolonged paced QRSd in patients with PPM is not determined. Methods We studied sixty-four patients (male:female=27:37, mean age=57.6 15.4 years) who had been on PPM (DDD: 15, VDD: 18, VVI: 31) for more than one year (mean: 68.2 44.0 months). LV function was normal before implantation of PPM. The 12-lead ECG and echocardiography were recorded prior to implantation, immediately after implantation and at the last follow-up. Results Paced QRSd did not significantly increase during the follow-up period. LVEF at the last follow-up (LVEF-FU) was significantly lower than that prior to implantation (59.3 11.5% vs. 64.9 10.1%, p=0.302, p180 ms than in patients without (44.4 12.0% vs. 61.7 9.5%, p180 ms during follow-up may suggest development of LV systolic dysfunction. New technologies to minimize prolongation of paced QRSd should be investigated to prevent LV systolic dysfunction after permanent ventricular pacing.