Prevalence and Predictors of Readmissions Among Patients with Hypertrophic Cardiomyopathy and Atrial Fibrillation/Flutter

Atrial fibrillation/flutter (AF) is the most common dysrhythmia in patients with hypertrophic cardiomyopathy (HCM). Unexplained left ventricular hypertrophy and left ventricular outflow tract (LVOT) obstruction are integral components of HCM pathology which can cause increased left atrial pressure and atrial myopathy contributing to the substrate for AF. Our aim was to determine the impact of AF on hospital readmissions in patients with HCM. We conducted a retrospective analysis using the 2015 - 2019 Nationwide Readmission Database to analyze the effect of AF on 30-day readmission and causes of 30-day readmission in patients with HCM. We also determined the hospital, patient and procedure-specific independent predictors of readmission in patients with HCM and AF. Among 191,235 index HCM hospitalizations, 81,390 (42.6%) had a secondary diagnosis of AF. A total of 16.9% patients with HCM and AF were readmitted within 30 days as compared with 14% of HCM patients without AF. The presence of AF was independently associated with a higher risk of all-cause 30-day readmission (HR 1.21, 95% CI 1.17 – 1.25, p < 0.001). The foremost etiology of 30-day readmission in HCM patients with AF was hypertensive heart and chronic kidney disease with heart failure, whereas, foremost etiology of 30-day readmission in HCM patients without AF was sepsis. Interventions aimed towards AF management (electrical cardioversion: aHR 0.91, 95% CI 0.82 – 1.01. p = 0.074, AF ablation: HR 0.92, 95% CI 0.74 – 1.13, p = 0.409, Watchman procedure: HR 1.50, 95% CI 0.16 – 14.6, p = 0.725) during index admission did not significantly impact the 30-day readmission in HCM patients with AF. Myectomy during index hospitalization (aHR 0.54, 95% CI 0.34 – 0.86, p = 0.010) was most strongly associated with a lower risk of 30-day readmission in HCM patients with AF. In conclusion, among patients hospitalized for HCM, presence of AF was associated with excess risk of 30-day all-cause readmission. Interventions aimed towards HCM management i.e. myectomy rather than interventions aimed towards AF management predicted lower readmission rate in this patient population.