Mortality associated with antiarrhythmic medication for atrial fibrillation among patients with left ventricular hypertrophy

Background: Atrial fibrillation (AF) guidelines recommend amiodarone as the preferred antiarrhythmic medication (AAM) in patients with left ventricular hypertrophy (LVH), due to potential pro-arrhythmic risk with other AAM. However, there are limited data to support this assertion. Methods: We retrospectively analyzed the records of 8204 patients who were prescribed AAM for AF and had transthoracic echocardiogram (TTE) at the multicenter, VA Midwest Health Care Network from 2000 to 2021. We excluded patients without LVH (septal or posterior wall dimension ≤1.4 cm). The primary outcome variable was all-cause mortality during antiarrhythmic therapy or within 6 months after stopping it. Propensity-stratified analyses were performed between amiodarone versus non-amiodarone (Vaughan-Williams Class I and III) AAM. Results: A total of 1277 patients with LVH (mean age 70.2 ± 9.5 years) were included in the analysis. Of these, 774 (60.6%) were prescribed amiodarone. Baseline characteristics of the two comparison groups were similar after propensity adjustment. After a median 1.40 years of follow-up, 203 (15.9%) patients died. Incidence rates per 100 patient-year follow-up was 9.02 (7.58–10.66) for amiodarone and 4.98 (3.91–62.56) for non-amiodarone. In propensity-stratified analysis, amiodarone use was associated with 1.58 times higher risk of mortality (95% CI 1.03–2.44; p =.038). Sub-group analysis in 336 (26.3%) patients with severe LVH showed no difference in mortality (HR 1.41, 95% CI 0.82–2.43, p =.21). Conclusion: Among patients with AF and LVH, amiodarone was associated with a significantly higher mortality risk than other AAM.