Effects of a high-fat diet on the electrical properties of porcine atria

BACKGROUND: Because obesity is an important risk factor for atrial fibrillation (AF), we conducted an animal study to examine the effect of a high-fat diet (HFD) on atrial properties and AF inducibility. METHODS: Ten 8-week-old pigs (weight, 18–23 kg) were divided into two groups. For 18 weeks, five pigs were fed a HFD (HFD group) and five were fed a normal diet (control group). Maps of atrial activation and voltages during sinus rhythm were created for all pigs using the EnSite NavX system. Effective refractory period (ERP) and AF inducibility were also determined. When AF was induced, complex fractionated atrial electrogram (CFAE) mapping was performed. At 18 weeks, hearts were removed for comparing the results of histological analysis between the two groups. Body weight, lipid levels, hemodynamics, cardiac structures, and electrophysiological properties were also compared. RESULTS: Total cholesterol levels were significantly higher (347 [191–434] vs. 81 [67–88] mg/dL, P=0.0088), and left atrium pressure was higher (34.5 [25.6–39.5] vs. 24.5 [21.3–27.8] mmHg, P=0.0833) in the HFD group than in the control group, although body weight only increased marginally (89 [78–101] vs. 70 [66–91] kg, P=0.3472). ERPs of the pulmonary vein (PV) were shorter (P<0.05) and AF lasted longer in the HFD group than in the control group (80 [45–1350] vs. 22 [3–30] s, P=0.0212). Neither CFAE site distribution nor histopathological characteristics differed between the two groups. CONCLUSIONS: The shorter ERPs for the PV observed in response to the HFD increased vulnerability to AF, and these electrophysiological characteristics may underlie obesity-related AF.