P6545Pacing as new predictor for atrial high rate episodes in patients with dual-chamber pacemakers and no history of atrial fibrillation

Abstract

Abstract Introduction Both atrial and ventricular pacing (AP/VP) have been related to a higher risk of clinical atrial fibrillation (AF) documented on ECG. Subclinical AF is detected as atrial high rate episodes (AHRE) by cardiac implantable electronic devices and is related to a higher risk of stroke. Purpose The aim of this study was to determine whether the percentage of AP and/or VP in patients with pacemakers and no history of AF is related with the future development of subclinical AF (AHRE) and/or clinical AF (ECG documented). Methods From February 2012 to September 2015 we recruited patients with dual chamber pacemakers and no prior history of AF. Patients were followed at 3 months and every year then after. Subclinical AF, clinical AF and cardiovascular events were registered. AHRE (subclinical AF) was defined as an episode of atrial rate ≥225 bpm with a minimum duration of 5 min. Clinical AF was defined as ECG documented AF. Percentage of AP/VP was determined as the mean AP/VP during the first three visits. Mortality and cardiovascular events (including AF, stroke and hospitalization for heart failure) were also recorded. Results 249 patients (57% men; 75±9 years-old) were included. Mean time from pacemaker implantation was 9 months and the main indication was AV-block in 53% of the patients. Mean CHA2DS2-VASc score was 3.5±1.5. After a mean follow-up of 33±11 months, 38.5% of patients developed subclinical AF and 10.4% clinical AF. Patients with AP≥50% presented significantly higher risk of AHRE (62.5% vs 32.3%, OR 3.48; 95% CI [1.93–6.4] p<0.01) and clinical AF (18.7% vs 8.6%, OR 2.4; 95% CI [1.05–5.52] p<0.05). Patients with VP≥50% presented significantly higher risk of AHRE (46.4% vs 31.6%, OR 1.87; 95% CI [1.10–3.24] p<0.05) and clinical AF (25.9% vs 9.7%, OR 2.7; 95% CI [1.13–7.72] p<0.05). The percentage of AP and VP were not related to a higher risk of cardiovascular events or mortality. Multivariate analysis showed that AP≥50% was an independent predictor for AHRE (OR 2.4; 95% CI [1.19–4.97] p=0.014). Conclusions Pacing is related to a higher risk for developing subclinical and clinical AF in patients with dual-chamber pacemakers and no history of previous AF. Our data suggest, that patients presenting a high percentage of AP and VP should be closely followed during routinely pacemaker check-ups assessing for subclinical AF, especially in those with AP ≥50%.