Atrial fibrillation: Risk factors, clinical features, and management

Abstract

Atrial fibrillation (AF) is a common supraventricular arrhythmia characterized by rapid and irregular atrial activation without a clear P-wave on an electrocardiogram. AF is classified as paroxysmal, persistent, or longstanding persistent, depending on its duration. The risk factors of AF are old age, hypertension, various cardiac diseases, obesity, obstructive sleep apnea, excessive alcohol intake, cardiac or thoracic surgery, pulmonary thromboembolism, hyperthyroidism, tachycardia or genetic factors. Symptoms of AF include fatigue, effort intolerance, palpitation, dyspnea, lightheadedness, polyuria, or syncope, but approximately 25% of patients are asymptomatic. Thromboembolism and heart failure are serious complications. The treatment for converting AF to sinus rhythm involves cardioversion, pharmacologic control, catheter ablation, or surgical treatment. Among them, catheter ablation and surgical treatment are fundamental since they electrically isolate and eliminate arrhythmic foci. Such electrical isolation was attempted in 1980 and established in 1987 as a Cox-Maze I procedure. The Cox-Maze procedure evolved to its third stage in 1988, and remains the standard lesion set for electrical isolation to this day. Catheter ablation, which was started in the 1990s by electrophysiologists, is less invasive than surgical treatment, but its results are unfavorable in cases of persistent or longstanding persistent AF. Meanwhile, surgical treatment is limited by its own invasive nature. Moreover, stand-alone surgical AF treatment is less often used than concomitant surgical treatment. To enable less invasive surgery, various ablation techniques have been developed to replace the classical cut-andsew technique of the Cox-Maze III procedure. In particular, the use of thoracoscopic epicardial ablation, which is performed with the heart beating, is on the rise. The ideal treatment for AF creates transmural lesions, is less invasive, and is feasible for persistent or longstanding persistent AF. The lesion transmurality of epicardial ablation has improved with the introduction of a bipolar radiofrequency clamp. However, epicardial ablation alone cannot make all Cox-Maze III lesion set. Thus, hybrid treatment consisting of thoracoscopic epicardial ablations, stapling or clipping of the left atrial appendage, and an electrophysiological study with endocardial touch-up ablations has been emerging in recent years. © 2020 by Nova Science Publishers, Inc. All rights reserved.