Pacing From the Right Ventricular Septum and Development of New Atrial Fibrillation in Paced Patients With Atrioventricular Block and Preserved Left Ventricular Function.

BACKGROUND

Whether pacing from the right ventricular (RV) septum improves prognosis is unclear. Furthermore, the clinical characteristics of patients who develop atrial fibrillation (AF) and cardiovascular events during long-term RV septal pacing have not been described.

METHODS AND RESULTS

We retrospectively evaluated the incidence of AF and cardiovascular events, including cardiac death, heart failure requiring hospitalization, or stroke, for a median of 4.0 years in 123 recipients of dual-chamber pacemakers implanted for atrioventricular block with preserved left ventricular function, who were free from AF before device implantation. AF developed in 30 patients (24%), and multivariable analysis suggested that the cumulative percentage of RV pacing was the only independent predictor of newly developed AF (hazard ratio: 1.19 for each 10% increment; 95% confidence interval: 1.04-1.41; P=0.01). Furthermore, older age, newly developed AF and a paced QRS duration ≥155 ms at pacemaker implantation were significant predictors of cardiovascular events.

CONCLUSIONS

RV septum pacing may induce AF in up to one-quarter of patients paced for atrioventricular block, according to the frequency of pacing. More importantly, in such patients, AF induced by RV pacing and a paced QRS duration ≥155 ms at pacemaker implantation are significantly associated with poor prognosis. Therefore, we recommend pacing from sites producing a paced QRS duration <155 ms and avoiding unnecessary RV pacing. (Circ J 2016; 80: 2302-2309).