Electrocardiographic alterations after chronic right ventricular apical pacing in patients with sinus node dysfunction

The purpose of this study is to investigate the potential to induce electrical remodeling by chronic right ventricular apical (RVA) in patients with sinus node dysfunction.

Ninety-two patients with sinus node dysfunction who underwent initial pacemaker implantation were included in the study. During routine clinic visits, electrocardiograms and echocardiograms were recorded. Forty-five patients were also studied as controls.

During a mean follow-up time of 3.3 +/- 0.5 years, the intrinsic QRS duration increased from 87 +/- 9 milliseconds before device implantation to 94 +/- 10 milliseconds (P < .001). The left ventricular end-diastolic diameter increased from 46 +/- 3 to 50 +/- 4 mm (P < .001), and the left ventricular ejection fraction decreased from 63% +/- 4% to 57% +/- 5% (P < .001). Logistic regression analysis revealed that elderly age at the time of pacemaker implantation (odds ratio [OR], 3.41; 95% confidence interval [CI], 1.07-10.90; P = .04), RVA pacing (OR, 3.91; 95% CI, 1.10-13.89; P = .03), and coronary artery disease (OR, 7.33; 95% CI, 1.09-50.29; P = .04) were independent predictors of the prolongation of intrinsic QRS duration.

The present study indicated that chronic RVA pacing may lead to a prolongation of intrinsic QRS duration, which could be independently predicted by elderly age, chronic RVA pacing, and the presence of coronary artery disease.