Clinical setting and prognostic significance of atrial fibrillation complicating acute myocardial infarction

Abstract

Clinical setting, presence and degree of heart failure (HF) of 80 consecutive patients who developed atrial fibrillation (AF) following acute myocardial infarction were compared to that of 620 patients with acute myocardial infarction and sinus rhythm admitted during the same period. 33 of 163 (20%) with initially mild HF developed AF compared to 5 of 74 (7%) with initially severe HF, and 42 of 463 (9%) without HF (P less than 0.01). Patients with mild HF who developed AF had a higher incidence of deterioration of clinical condition (39 vs 14%, P less than 0.005) and a higher mortality rate (52 vs 22%, P less than 0.001) than patients with mild HF and sinus rhythm. The presence of AF influenced neither the development of HF and mortality rate in patients without HF nor the degree of HF and mortality in patients with initially severe HF. Pericarditis was present in 12 of 42 (28%) with AF occurring in the absence of HF, compared to 3 of 38 (8%) with AF and initially mild HF and to 56 of 620 (9%) with sinus rhythm (P less than 0.05).

Conclusions: (1) in the absence of HF, AF may be the consequence of pericarditis; (2) in patients with mild HF, AF may be consequence of HF; (3) the contribution of AF to the subsequent clinical course is only of prognostic significance in patients with mild HF.