Atrial stunning, inflammation and nutritional status after cardioversion from atrial fibrillation

BACKGROUND: Conversion of atrial fibrillation (A-Fib) to sinus rhythm is associated with transient mechanical dysfunction of left atrium and appendage, termed atrial stunning. OBJECTIVES: The aim of the present study was to evaluate the relationship between nutritional status and atrial stunning after conversion of A-fib. METHODS: Fifty-eight hemodynamically stable patients referred for cardioversion for lone AF were included in this study. To assess nutritional status and inflammation we measured: hemoglobin, erythrocyte mean cell volume, increased transferrin, decreased percent transferrin saturation and ferritin, albumin, CRP and Fe. Usual dietary intake was assessed with the use of a semi-quantitative food frequency questionnaire. LA function was assessed using peak atrial filling velocity, atrial ejection force and peak of emptying and filling velocities of left atrial appendage. RESULTS: Patients were categorized in 4 groups according to value of CRP and Fe. Patients with normal value of CRP and normal value of Fe and patients with elevated CRP but normal value of Fe showed no difference in parameters of atrial function. On contrary patients with reduced value of Fe showed significantly reduced parameters of atrial function. CONCLUSIONS: Data of the present study showed that patients with a reduction of Fe present a marked dysfunction of atrial contractility in comparison with other groups. We cautiously hypothesize an iron mechanism. The hemodynamic stress due to A-Fib can generate highly toxic hydroxyl radicals. These oxygen free radicals probably damage cells by oxidating various cell components and could be important in inducing myocardial stunning after A-Fib.