Atrial fibrillation with slow-ventricular response (AF-SVR): A literature review

Atrial fibrillation is a common cardiac arrhythmia affecting over 33 million individuals globally; however, atrial fibrillation with slow-ventricular response (AF-SVR) remains an underexplored subset. AF-SVR is characterized by an irregular ventricular rate of less than 60 beats per minute without the influence of atrioventricular (AV) blocking agents. This review aims to consolidate current knowledge on AF-SVR, focusing on the epidemiology, pathophysiology, clinical manifestations, complications, diagnosis, and management strategies. AF-SVR is more prevalent in older adults, often attributed to age-related degeneration of the cardiac conduction system. Conditions such as AV nodal block, sick sinus syndrome (SSS), and the effects of certain medications are significant contributors to the development of AF-SVR. The pathophysiology involves complex electrical and structural remodeling of the atria, which can lead to bradycardia and symptomatic conduction delays. Clinically, AF-SVR presents similarly to other forms of bradycardia, with symptoms including fatigue, dizziness, and syncope. Diagnosis is primarily based on electrocardiogram (ECG) findings of AF with a slow-ventricular rate, supplemented by ambulatory ECG monitoring and exercise tolerance testing. Transthoracic echocardiography (TTE) is crucial for identification of underlying structural heart disease. Management of AF-SVR involves first addressing reversible causes such as medication effects, electrolyte imbalances, and underlying ischemia. Pharmacological options including the use of anticholinergic medications such as theophylline and hyoscyamine, which have shown efficacy in reversing bradycardia. Persistent or severe cases often require permanent pacemaker implantation to maintain adequate heart rates and prevent complications. This review highlights the need for further research on AF-SVR, particularly regarding non-invasive treatment options and the long-term outcomes of different management strategies. Understanding the unique challenges of AF-SVR is essential for optimizing patient care and improving clinical outcomes. Future studies should focus on establishing comprehensive guidelines for the diagnosis and management of AF-SVR.