Use of class ic antiarrhythmic drugs in atrial fibrillation with structural heart disease: a nationwide cohort study

Use of class IC antiarrhythmic drug (AAD) is limited in atrial fibrillation (AF) patients with structural heart disease. This study investigated the safety and feasibility of class IC AADs compared with those of class III AADs in patients with AF and structural heart disease.

Based on the nationwide health insurance database, patients first diagnosed with AF between 2013 and 2019 were screened, and those with a diagnosis of either hypertrophic cardiomyopathy, obstructive coronary artery disease, or heart failure were included. The primary outcome was the composite of all-cause mortality, sudden cardiac arrest, and ventricular arrhythmia. A total of 38,378 patients were analyzed. Class IC and III AADs were prescribed to 10,034 and 28,344 patients, respectively. Patients in the class III AAD group were older and had higher CHA2DS2-VASc scores than those in the class IC AAD group. The class III AAD group had a higher risk of primary outcome (hazard ratio 2.36, 95% confidence interval 1.93–2.89, p<0.001). The risks of heart failure hospitalization (4.73, 3.73–6.00, p<0.001) and coronary revascularization (2.70, 1.85–3.95, p<0.001) were also higher in the class III AAD group. However, the risk of atrial flutter did not differ significantly (1.61, 0.92–2.82, p=0.096).

In patients with AF and structural heart diseases, the use of class IC AAD was associated with lower risk of adverse cardiovascular events. Class IC AADs may be an option for rhythm control in patients with AF and stable structural heart disease.