ATRIAL FIBRILLATION IN PATIENTS WITH INFERIOR MYOCARDIAL INFARCTION

Objective: To elucidate the mechanism of atrial fibrillation and evaluate left atrium function after restoration of sinus rhythm in patients with acute posterior wall myocardial infarction ( MI). Materials and Methods: The study included 53 patients with posterior wall MI.All patients were divided into 2 groups. The first group consisted of 33 a people with paroxysms of atrial fibrillation (AF), and the second included 20 control subjects without arrhythmia. All percutaneous intervention was performed within the first 24 hours. Patients were evaluated for time and duration of paroxysms, the size of the heart chambers and the recovery time of the left atrium (LA)function. Results: Patients with posterior wall myocardial infarction developed AF in the early stages of the disease (in 91% on the first day), with short duration of paroxysms, stopped spontaneously and often within 1 hour (in 11 people). There were no significant differences in the size of the heart chambers, left ventricular contractility and hemodynamic disturbances in patients of both groups. AF in most cases developed in patients without left ventricular failure (in 27 people; 82%). Wherein the proximal right coronary artery occlusion was observed more frequently in patients with atrial fibrillation, than in the control group (17 vs 2; p <0,001). Approximately half patients(16 ) with AF before the appearance of atrial fibrillation bradysystolya of atria (less than 50 in 1 min) was recorded, due to acute sinus node dysfunction. After the reversion of sinus rhythm mechanical function of the LA was absent in only 4 people with left ventricular failure. Effective systole of LA was restored only 7 days after reversion to sinus rhythm. The rare occurrence of mechanical dysfunction after discontinuation of arrhythmia indicates a low probability of thrombosis and embolism in the systemic circulation. Conclusion: In cases of patients with posterior wall localization of MI main causes of AF include acute ischemia of atria due to occlusion of the right coronary artery above the branches supplying atrium. Atrial bradysystolya due to acute sinus node dysfunction often contributes to the development of AF as a substitute atrial rate (acute syndrome of tachy-bradycardia). In case of patients with posterior wall MI AF episodes were rarely accompanied by hemodynamic disturbances and the risk of systemic thromboembolism after reversion to sinus rhythm was low.

atrial fibrillation, myocardial infarction, cardioversion