Introduction: Patients with atrial fibrillation (AF) have higher mortality rates. Underlying cardiac disease and co-morbidities that AF aggravates could explain these observation.
Pacemaker implantation in patients with AF, could have an impact on patient prognosis, as a wide paced QRS with a left bundle block configuration is created, with a harmful effect on cardiac performance. There is some evidence of the benefit of septal stimulation which achieves a narrower QRS and generates a different activation pattern.
Objectives: Compare survival between two different sites of stimulation in the right ventricle in patients with history of with atrial fibrillation and a left ventricular ejection fraction above 40% that received a permanent pacemaker.
Methods: We studied 3136 patients from our AF registry, 568 received a permanent pacemaker. Mean follow-up was of 48 ± 38 months. Patients were divided into two groups, depending on the stimulation site (right ventricular apical or septal). All had a left ventricular ejection fraction above 40 %. We compared survival between the two groups.
Results: The right ventricular electrode was implanted in two different positions; right ventricular apex in 429 patients (75%) and right ventricular septum in 139 patients (25%). When mortality was compared between the two groups, the apical group showed a mortality of 172/429 (40%) and the septal stimulation group of 35/139 (25%). One tail without Yates correction Chi2 = 2.77, p = 0.048]
Survival curves were analyzed in the same population, comparing apical versus septal stimulation. The curves were significantly different favoring septal stimulation, that showed a significant lower mortality (log rank Mantel-Cox Chi2 4664 p = 0.031).
Conclusions: In this retrospective study, it appears that patients with documented AF and a preserved left ventricular ejection fraction (>40%) whom underwent permanent pacemaker implantation the site of right ventricular stimulation has an impact on mortality. Apical pacing showed a significant higher mortality when compared to septal stimulation.