Restrictive Left Ventricular Filling Pattern and Risk of New-Onset Atrial Fibrillation After Acute Myocardial Infarction
What are the predictors of new-onset atrial fibrillation (AF) after an acute myocardial infarction (MI)?
An echocardiogram was performed a median of 2 days after admission in 1,169 patients (mean age 64 years) with an acute MI. The primary outcome was new-onset AF during 6 months of follow-up.
New-onset AF occurred during 6 months of follow-up in 110 patients (9.4%). After adjustment for clinical risk factors, the independent predictors of new-onset AF were age ≥68 years (hazard ratio [HR], 2.98), a restrictive filling pattern (HR, 2.48), Killip class >1 (HR, 1.71), and left atrial diameter >4 cm (HR, 1.49).
The authors concluded that left ventricular diastolic dysfunction is an independent predictor of new-onset AF after an acute MI.
The potential mechanisms of AF after an MI include inflammation, neurohormonal changes, and an increase in left atrial pressure. A restrictive filling pattern reflects left ventricular diastolic dysfunction, which is associated with an increase in left atrial pressure. The increase in left atrial pressure activates atrial stretch receptors, explaining the heightened vulnerability to AF when a restrictive left ventricular filling pattern is observed after MI.
Keywords: Myocardial Infarction, Heart Atria, Follow-Up Studies, Heart Ventricles, Echocardiography
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