Diastolic Dysfunction and Atrial Fibrillation
Is there an association between echocardiographic measurements of diastolic dysfunction and risk of atrial fibrillation (AF) in a population-based cohort?
As part of the Tromsø Study, 2,406 participants were followed from 1994 to 2010. All subjects underwent echocardiograms. Left atrial (LA) size and transmitral flow pattern were analyzed in each participant. Clinical information was obtained on a variety of cardiovascular risk factors.
Mean age was 62.6 years. AF was detected in 462 subjects, resulting in the incidence rate of 12.6 per 1,000 person-years. Using a multivariate Cox proportional hazards regression analysis, a moderately enlarged LA was associated with a 60% increased risk of AF, and severely enlarged LA had a hazard ratio for AF of 4.2. Abnormal mitral Doppler flow adjusted for predictor variables did not show a statistically significant association with AF risk. However, when LA size was also adjusted for, the risk of AF increased by 30% (95% confidence interval, 1.0-1.6).
An enlarged LA is a predictor of AF in both sexes. Transmitral inflow is not by itself associated with increased risk of AF, but it enhances the predictive power of the LA size.
Prior studies have shown that increased LA size is associated with increased risk for AF. Some prior studies in older participants, as well as patients post-myocardial infarction, also found a positive relationship between mitral Doppler indices and the risk of AF. Increased LA pressure is associated with AF initiation. Increased LA size in patients without significant valvular disease signifies long-lasting LA pressure overload. The present study showed that transmitral inflow–derived indexes of diastolic function are only associated with increased risk of AF if they are seen concomitantly with increased LA size. It may be that patients in this study were too young or their follow-up was too short for echo-derived diastolic dysfunction indexes to demonstrate an independent association with subsequent AF. Of note, sleep apnea, a previously underappreciated risk factor for AF, has not been factored into the analysis.
Clinical Topics: Arrhythmias and Clinical EP, Noninvasive Imaging, Prevention, Implantable Devices, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, Echocardiography/Ultrasound
Keywords: Arrhythmias, Cardiac, Atrial Fibrillation, Echocardiography, Echocardiography, Doppler, Heart Atria, Primary Prevention, Risk Factors
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