P5823Atrial fibrillation or rapid ventricular response in patients with left ventricular dysfunction: which is relevant to the long-term clinical outcome?

Background: In patients with left ventricular dysfunction (LVD), both Atrial Fibrillation (AF) and heart-rate are considered ominous. However, their prognostic implications are debated, and outcome data are discordant. Large and extensively characterized clinical practice series with long-term outcome focused on the implications of cardiac rhythm and heart-rate on survival are lacking. Purpose: To investigate whether heart rhythm (AF vs. SR) or heart-rate independently affect prognosis of patients with LVD and to assess the magnitude of their mortality effect in a cohort of patients diagnosed with LVD in routine clinical practice. Methods: Consecutive patients with LVD (EF <50%), comprehensive comorbidity, echocardiographic and electrocardiographic data were enrolled at Mayo Clinic 2003–2011. AF was diagnosed by ECG. Heart-rate was defined throughout echocardiography. Organic valve disease, previous valve surgery, congenital, hypertrophic or infiltrative myocardial diseases were excluded. Results: We included 16709 patients (age 67±14 years, heart rate 77±19 bpm). AF was diagnosed in 3304 patients (20%).Compared to SR, AF patients were older (73±12 vs. 67±15, p<0.0001), more frequently males (76 vs. 67%, p<0.0001), had higher heart rates (84±21 vs. 75±17 bpm, p<0.0001), but had similar EF (36±9 vs. 36±10%, p=0.9).