Key result
Class III AADs linked to ~136% higher risk of major events vs class IC in AF.
Why the study?
Use of class IC antiarrhythmic drugs is limited in structural heart disease, and their safety compared to class III antiarrhythmic drugs in patients with atrial fibrillation and structural heart disease required investigation.
Do class IC antiarrhythmic drugs reduce adverse cardiovascular events compared to class III antiarrhythmic drugs in patients with atrial fibrillation and structural heart disease?
Cohort (n=38,378)
Do class IC antiarrhythmic drugs reduce adverse cardiovascular events compared to class III antiarrhythmic drugs in patients with atrial fibrillation and structural heart disease?
Hazard Ratio: 2.36 (95% CI 1.93–2.89)
Absolute Event Rate: 48.5% vs 342.2%
p-value: p=<0.001
In patients with atrial fibrillation and structural heart disease, class IC antiarrhythmic drugs were associated with a significantly lower risk of adverse cardiovascular events compared to class III antiarrhythmic drugs.
Class IC AADs associated with lower risk than class III in this cohort; leaves open confirmation before any practice change.
Use of class IC antiarrhythmic drugs (AADs) is limited in structural heart disease. This study investigated the safety of class IC AADs compared to class III AADs in patients with atrial fibrillation (AF) and structural heart disease. Based on the national 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 CHA 2 DS 2 -VASc scores than those in the class IC AAD group. The class III AAD group had a higher risk of primary outcomes (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. 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 disease, class IC AADs were associated with a lower risk of adverse cardiovascular events. Further randomized trials are needed to confirm these observations.
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Jeong et al. (2026) conducted a cohort in Atrial fibrillation with structural heart disease (n=38,378). Class IC antiarrhythmic drugs vs. Class III antiarrhythmic drugs was evaluated on Composite of all-cause mortality, sudden cardiac arrest, and ventricular arrhythmia (HR 2.36, 95% CI 1.93-2.89, p=<0.001). In patients with atrial fibrillation and structural heart disease, class III antiarrhythmic drugs were associated with a significantly higher risk of the primary composite outcome compared to class IC drugs (HR 2.36).
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