Improvement of peripheral microcirculation after cardioversion of atrial fibrillation

Near-infrared spectroscopy (NIRS) is a noninvasive method to measure regional tissue oxygenation (rSO₂ ). In patients with atrial fibrillation (AF), cardiac output and endothelial function are altered. Peripheral tissue oxygenation may therefore be reduced. This study aims to describe the peripheral tissue oxygenation of the feet before and after synchronized electrical cardioversion (CV) of patients with AF using NIRS.

Patients with AF undergoing CV were included and screened for peripheral arterial disease (PAD), diabetes mellitus (DM), and peripheral neuropathy (PN). NIRS was performed before and after CV under continuous ECG and monitoring of peripheral oxygen saturation. NIRS was registered on the dorsoplantar and plantar area of both feet. Capillary blood gas analysis was performed and left ventricular ejection fraction (LVEF) was determined.

Twelve patients (five women, seven men, age 70.8 ± 10.8 years) participated. None had history of PAD. DM was present in three (25%) patients. Two patients (16.7%) had PN. CV was successful in 11 patients. Overall, rSO₂ improved significantly in all patients after CV (P = .0003). Mean improvement was 7.17%. There were no significant changes in body temperature, ankle-brachial index, sO₂ , pO₂ , pCO₂ , pH, or lactate after CV. Heart rate was significantly lower (P < .0001) and LVEF significantly higher (P = .0123) after CV.

In patients with AF, peripheral tissue oxygen saturation improves significantly after successful CV. This suggests that patients with PAD may not only benefit from interventional or surgical improvement of arterial vascularization, but also from CV in case of AF.