Prevalence and Prognostic Significance of Left Ventricular Dysfunction in Patients Presenting Acutely with Atrial Fibrillation

Abstract

Condensed Abstract: The prevalence and prognostic importance of CM occurring as a consequence of AF is poorly defined. This study investigated the incidence of CM in patients with AF, its clinical features and long-term outcomes. We demonstrated that CM is common in patients presenting acutely with newly diagnosed rapid AF, and carries a worse long-term prognosis. Systolic dysfunction was reversible in an important proportion of patients, suggesting a greater prevalence of rate-related CM in AF than has previously been postulated. This underscores the importance of appropriate rhythm management strategies and repeat imaging studies. Summary Background: Atrial fibrillation (AF) may precipitate LV dysfunction, potentially leading to cardiomyopathy (CM). The prevalence and prognostic importance of CM occurring as a consequence of AF is poorly defined. We investigated the incidence of CM in patients with AF, its clinical features and long-term outcomes. Methods: We reviewed 292 consecutive patients (average age 72 ± 13yrs) presenting acutely with AF and tachycardia over a 3 year period from June 2004. Clinical details were obtained from medical records. CM was defined as ejection fraction (EF) ≤ 50% on index admission. Results: Echo was performed 93% of patients at index admission, and 69 (24%) had CM (average EF% = 37 ± 11), 60 of which were newly diagnosed. Patients with CM had significantly higher presenting heart rate (141 ± 19 vs. 132 ± 23 bpm), larger end-diastolic (5.7 vs. 5.2 cm) and end-systolic (4.5 vs. 3.2 cm) dimensions, and larger left atrial size (4.6 vs. 4.3 cm) (P < 0.05 for all). They were also statistically more likely (P < 0.05) to be male, present with breathlessness, have a history of coronary disease, and be treated with digoxin and warfarin. Follow-up echo between 6 and 12 months was performed in 46% of patients with new CM, and average EF rose to 53 ± 12%. At an average follow-up of 2.5 years, there was a significant increase in mortality in CM patients (16% vs. 9.5%, P < 0.05). Conclusion: CM is common in patients presenting acutely with newly diagnosed rapid AF, and carries a worse long-term prognosis. Systolic dysfunction was reversible in an important proportion of patients, suggesting a greater prevalence of rate-related CM in AF than has previously been postulated. This underscores the importance of appropriate rhythm management strategies and repeat imaging studies.