Update on Atrial Fibrillation: Part I

Abstract

SummaryAtrial fibrillation (AF) is an epidemic, affecting 1% to 1.5% of the population in the developed world. Projected data from the population-based studies suggest that the prevalence of AF will grow at least 3-fold by 2050. The health and economic burden imposed by AF and AFrelated morbidity is enormous.Atrial fibrillation has a multiplicity of causes ranging from genetic to degenerative, but hypertension and heart failure are the commonest and epidemiologically most prevalent conditions associated with AF as both have been shown to create an arrhythmogenic substrate. Several theories emerged regarding the mechanism of AF, which can be combined into two groups: the single focus hypothesis and the multiple sources hypothesis. Several lines of evidence point to the relevance of both hypotheses to the mechanism of AF, probably with a different degree of involvement depending on the variety of AF (paroxysmal or persistent). Sustained AF alters electrophysiological and structural properties of the atrial myocardium such that the atria become more susceptible to the initiation and maintenance of the arrhythmia, a process known as atrial remodeling. Angiotensin II has been recognized as a key element in atrial remodeling in association with AF opening the possibility of exploitation of "upstream" therapies to prevent or delay atrial remodeling. The clinical significance of AF lies predominantly in a 5-fold increased risk of stroke. The limitations of warfarin prompted the development of new antithrombotic drugs, which include anticoagulants, such as direct oral thrombin inhibitors (dabigatran) and factor Xa inhibitors (rivaroxaban, apixaban). Novel mechanical approaches for the prevention of cardioembolic stroke have recently been evaluated: percutaneous left atrial appendage occluders, minimally invasive surgical isolation of the left atrial appendage, and implantation of carotid filtering devices.

Current management of atrial fibrillation

“…14 Dabigatran is the first drug to show non-inferiority to warfarin for stroke prevention in atrial fibrillation. 4,[14][15][16] The 150 mg twice-daily dose was superior to warfarin in efficacy with a similar risk of major bleeding whereas 110 mg twice daily was non-inferior for efficacy with a reduced risk of major bleeding.…”

“…It can also develop following cardiac surgery or excess consumption of alcohol. [3][4][5] Symptoms include palpitations, dizziness, dyspnoea, angina and worsening heart failure. 1,3,5 Atrial fibrillation may be categorised according to its presentation (initial, paroxysmal or recurrent, persistent) and duration.…”

Factors to Predict Recurrence of Atrial Fibrillation in Patients with Hypertension

“…The electrophysiological mechanisms of atrial fibrillation onset in humans have been referred to as dispersion of refractoriness or conduction within the atria. 4 Hypertension could result in cardial anatomy and electrophysiologic changes. The persistence of higher pressure of the systemic artery may produce left ventricular hypertrophy, which then increased the volume load of the left atrium and deduced left atrium remodeling.…”

Atrial Fibrillation Analysis for Real Time Patient Monitoring

“…AF is linked with stroke, heart failure, risk of death and coronary artery disease and found to be connected with significant morbidity and mortality [4,5]. Approximately 12 million North Americans and Europeans suffer from AF and this is estimated to triple in the next 30 to 50 years [6]. The prevalence of AF rises with age.…”