Invasive Coronary Physiology Assessment in Patients With Arrhythmia‐Induced Cardiomyopathy

ABSTRACT Background Arrhythmia‐induced cardiomyopathy (AIC) is defined as impaired left ventricular function due to cardiac arrhythmias. We sought to investigate the association between coronary microvascular dysfunction (CMD) and AIC in patients with atrial fibrillation (AF). Methods In this multicenter observational study, we enrolled consecutive patients with recent diagnosis of AF (<6 months) who underwent invasive coronary physiology assessment with the bolus thermodilution technique. Patients were divided into two groups according to left ventricular ejection fraction (LVEF): AIC group if LVEF < 50% and preserved LVEF group if LVEF ≥ 50%. A third group of patients with a recent diagnosis of dilated cardiomyopathy (DCM) and without AF was analyzed as control group. CMD was defined as abnormal coronary flow reserve (CFR < 2.5) and/or abnormal index of microcirculatory resistance (IMR ≥ 25). Results Among 84 analyzed patients, 33 were in the AIC group, 39 in the preserved LVEF group, and 12 in the DCM group. CMD was more frequently detected in the AIC group compared to the preserved LVEF (79% vs. 38%, p < 0.001) and DCM groups (79% vs. 33%, p = 0.01). In patients with AF, a significant correlation was found between CFR and LVEF (beta coefficient: 3.8; 95% CI: 1.8−5.9; p < 0.001), and IMR and LVEF (beta coefficient: −0.3; 95% CI: −0.4 to −0.1; p = 0.001). At multivariable analysis, CMD was independently associated with AIC (adjusted odds ratio: 6.2; 95% CI: 2.2 to 20.1; p = 0.001). Conclusions CMD is strongly and independently associated with the degree of left ventricular dysfunction and may play a role in the development of AIC in patients with AF.