Abstract 2937: Unexpectedly Low Incidence of Atrial Fibrillation in Heart Failure Patients Treated by Cardiac Resynchronization Therapy
Background Atrial fibrillation (AF) is common (up to 30–50%) in patients with severe and drug-refractory heart failure (HF) classically indicated for cardiac resynchronization therapy (CRT). However, no current information about the real AF incidence is available in the patients treated by CRT. The CHAMP-study (Congestive Heart Failure Atrial Arrhythmia Monitoring and Pacing) has been designed to characterize AF in HF patients treated with CRT pacemaker.
Methods The CHAMP study is a prospective, European, multi-center, non-randomized clinical trial conducted in CHF patients who remain symptomatic in NYHA class III or IV despite optimal medical treatment. The primary endpoint was AF burden. Clinical endpoints were assessed at the end of follow-up and compared to their baseline values. Mean follow-up time was 28 weeks, with two observational periods (weeks 2–15; weeks 16–28). The implanted device was the Vitatron CRT 8000 biventricular pacemaker fitted with specific AF monitoring capabilities. AF therapy algorithms were switched off for the duration of the study to avoid interference with the natural history of AF. During the follow up period the device collected data on occurrence, number and mode of onset of AF episodes. AF was defined as more than 10 consecutive atrial beats with an A-A interval of < 300 msec.
Preliminary Results 173 patients were included. 39 pts were withdrawn for death (9), failure of LV lead implantation (20) or other reasons (10). Mean age was 66.6 years. 67% were males. 91% pts were in NYHA class III. 33.5% had a history of atrial tachyarrhythmia. The baseline mean LVEF and QRS duration were 25% and 170 ms, respectively. 90% received ACE inhibitors, 65% beta-blockers and 36% were under anti-arrhythmic therapy. Preliminary results showed documented AF in 9 % at 15 weeks and 11% at 28 weeks. The overall incidence was 15%, meaning that during the total follow-up period, only 15% of the study-population developed AF in any form.
Conclusion: Results of the CHAMP study showed that in this conventional CRT population, the real incidence of AF is much lower than anticipated.