Obesity Begets Atrial Fibrillation

A 68-year-old man presents to his primary care physician describing an irregular and rapid heartbeat that has awakened him from sleep. The patient has a blood pressure of 148/92 mm Hg, a body mass index (BMI) of 35.5 kg/m2, and a history of diabetes mellitus that has been managed with oral glycemics. On auscultation, the physician appreciates occasional irregular beats without a cardiac murmur. An ECG shows normal sinus rhythm with a PR interval of 180 milliseconds and infrequent premature atrial contractions. A 24-hour Holter monitor identifies intermittent premature atrial contractions and demonstrates paroxysmal atrial fibrillation (AF) that is primarily nocturnal. The patient’s inquires about (1) how obesity has contributed toward his developing AF, and (2) whether weight loss would ameliorate the risk of AF or the burden of the arrhythmia.Obesity is a profound public health concern with increasing prevalence. AF is the most commonly encountered clinical arrhythmia and results in multiple adverse sequelae that include stroke, heart failure, cognitive decline, dementia, diminished quality of life, and death.1 In community- and population-based cohort studies, obesity has consistently emerged as a risk factor for AF. In comparison with normal-weight referents, obese individuals have up to a 2.4-fold increased AF risk.2 In cardiothoracic surgery cohorts, the postoperative risk of AF ranges from a 1.4- to 2.4-fold increased risk in comparison with nonobese referents.3,4 The risk of AF increases progressively with rising BMI. In a large cardiothoracic surgery series, individuals at the extreme of BMI (≥40.0 kg/m2) had a 2.3-fold increased postoperative AF risk in comparison with a 1.2-fold increased risk in the overweight (BMI 25–30 kg/m2).4 An observational cohort from the Mayo Clinic similarly showed increased likelihood of …