Introduction:
Obesity is a risk factor for atrial fibrillation (AF), and reduction of weight has been shown to reduce the burden of AF. However, the exact underlying pathogenesis is unknown.
Hypothesis:
We hypothesize that obesity is related with impaired left atrial function, measured with echocardiographic strain analysis, in young patients (<60 years) with recent onset AF (AF history< 3 years).
Methods:
We studied 94 patients of the Phenotyping young-onset AF patients study, all with sinus rhythm during echocardiography. Detailed clinical and echocardiographic information was collected. Three strain-patterns (reservoir, activation, and conduit strain) representing left atrial functional phases were measured.
Results:
Of the 94 patients, 32 were obese and 62 were non-obese (34±3 kg/m2 vs. 25±2 kg/m2, p<0.001). Mean age was 50±9 years and 34% were women. No significant differences in cardiovascular conditions and risk factors were found, except for diabetes mellitus (13% vs. 2%, p=0.026), and metabolic syndrome (56% vs. 8%, p<0.001), both more common in obese patients. Left atrial volume index (mean 30±8ml/m2), and left ventricular mass index and ejection fraction were not significantly different between both groups. However, the left atrial reservoir (27±8 vs. 33±10%, p=0.008) and conduit strain (16±6 vs. 20±8%, p=0.011) were significantly reduced in obese patients, the left atrial activation strain was not (p=0.118). Using linear regression analysis adjusting for significant baseline differences, the association between reservoir strain (beta=-0.304, p=0.013), and conduit strain (beta=-0.246, p=0.045) and obesity remained significant. The correlation between BMI and left atrial function are shown in the figure.
Conclusions:
In young patients with recent onset AF, obesity is associated with impaired left atrial function, in absence of dilatation. Left atrial dysfunction may be the first sign of atrial remodeling in obese AF patients.
Left atrial function in obese and non-obese patients undergoing percutaneous pulmonary vein isolation
