Mortality and cause of death in patients with chronic non-rheumatic atrial fibrillation after a two-year follow-up.

BACKGROUND

Non-rheumatic atrial fibrillation (NRAF) is a very common arrhythmia but its role in the prognosis and cardiovascular mortality is controversial. In particular, cause and predictors of death are not completely known.

METHODS

We analyzed the cause of death and the possible predictors of cardiovascular mortality in 664 outpatients (mean age 72 +/- 9 years old) enrolled in the "Trieste Area Study on Non-Rheumatic Atrial Fibrillation" (TASAF), a prospective community study, after a follow-up of 27 +/- 9 months. The mean duration of the arrhythmia at enrollment was 59 months (range 1-360 months). Only 42 patients (6.3%) were on anticoagulants by general practitioners and 205 (30.8%) were on antiplatelet drugs.

RESULTS

Of these patients, 110 (16.5%) died: 28 (25.5%) due to a cerebral or peripheral thromboembolism, 10 (8.2%) of sudden death, 46 (42.7%) of expected cardiac death and 25 (22.7%) of non-cardiac causes. In one patient, the cause of death was uncertain. Sixty-nine patients underwent postmortem examination. In univariate analysis, left ventricular dysfunction (p = 0.03) and an enlarged left atrium (p = 0.03) proved to be directly related to increased cardiovascular mortality. Both in univariate and Cox proportional hazards model analysis, aging (odds ratio 1.09, IC 95% 1.05-1.12, p = 0.00001), history of heart failure (odds ratio 1.27, IC 95% 1.01-1.60, p = 0.036), cardiomegaly (odds ratio 1.35, IC 95% 1.01-1.81, p = 0.040), diabetes mellitus (odds ratio 1.35, IC 95% 0.99-1.84, p = 0.058) and previous myocardial infarction (odds ratio 1.56, IC 95% 1.20-2.03, p = 0.0007) were all independent risk factors for cardiovascular mortality. A history of cerebral or systemic embolism (23 versus 12%, p = 0.09) and, above all, one or more recurrences before enrollment (11 versus 2.3%, p = 0.04), were associated with embolic mortality.

CONCLUSIONS

Patients with NRAF have an increased risk of cardiovascular death. Aging, the presence of diabetes, cardiomegaly on chest x-ray, heart failure and a previous myocardial infarction were independent risk factors for cardiovascular mortality. A history of embolism at enrollment significantly conditioned the embolic mortality rate but above all, embolic events during follow-up determined a very high percentage of total deaths (25.5% of all causes). A proper anticoagulant therapy should strongly be advised to all patients with no contraindications.