Exploring Risk Indicators of Atrial Fibrillation in Severe Obesity: Left Atrial Cardiomyopathy and Premature Atrial Contractions

Background: Although obesity is a major risk factor for atrial fibrillation (AF), its mechanisms and the diagnostic yield of AF screening in severe obesity is unclear. This study aims to enhance our comprehension of AF susceptibility in severe obesity by investigating associations between left atrial (LA) cardiomyopathy and premature atrial contractions (PACs) and to explore the diagnostic yield of AF screening.

Methods: This cross-sectional study included a total of 192 subjects aged 35-65 years with a BMI ≥ 35 kg/m, alongside 50 non-obese controls, both without known cardiac disease. Prolonged heart rhythm registration was done with either 24-hours (n = 147) or 7-day Holter monitoring (n = 75) or an implantable loop recorder (ILR) (n = 10). Furthermore, we performed conventional transthoracic echocardiography and strain analyses.

Results: In the obese cohort, LA enlargement was independently associated with PAC frequency. Each SD increment (10 ml/m) of LA volume index corresponded with a 46 % increase in PACs. An increase of each SD (10 %) LA reservoir strain was associated with a decrease of 16 % in PAC frequency. There was no association found between LA cardiomyopathy and PACs in the control group. AF was not detected in any subject.

Conclusion: LA enlargement was independently associated with more frequent PACs in severe obesity, a well-known AF precursor. There was a noticeable trend suggesting a relation between impaired LA function and PACs. Considering our observed low diagnostic yield of AF screening within this population, further investigation is needed to determine whether incorporating LA cardiomyopathy as an additional risk measure could improve AF screening strategies for individuals with severe obesity.