185 - Arrhythmia Burden and Its Effect on in-Hospital Outcomes in Patients with Hypertrophic Obstructive Cardiomyopathy

Abstract

Background: Hypertrophic obstructive cardiomyopathy (HOCM) is known to be associated with supraventricular and ventricular arrhythmias. The burden of such arrhythmias and its effect on in-hospital outcomes in patients hospitalized with HOCM is not clear. Objectives: Our aim was to identify the burden of arrhythmia and its effect on in-hospital mortality in patients hospitalized with HOCM in recent years (2008 - 2014) using National Inpatient Sample (NIS). Methods: We identified patients who were hospitalized with primary diagnosis of HOCM using International Classification of Diseases codes - 9th edition (ICD-9) code 425.11. We identified presence of arrhythmias in this group using appropriate ICD-9 codes. We used multivariate binary logistic regression and multivariate linear regression to identify predictors associated with in-hospital mortality, length of stay (LOS), and total hospital charges respectively. Results: We identified 8534 patients discharged with diagnosis of HOCM. A total of 2880 (33.7%) patients had concomitant diagnosis of any arrhythmia. Among patients with HOCM, 235 (2.8%) patients had ventricular fibrillation (VF), 2025 (23.7%) had atrial fibrillation (AF), 324 (3.8%) had atrial flutter (AFL), 347 (4.1%) had atrioventricular nodal blocks, and 268 (3.1%) had premature beats. The in-hospital mortality in arrhythmia group was 2.6% compared to 1.5% in non-arrhythmia group. We found that only VF had significant effect on in-hospital mortality with these patients having adjusted odds ratio (AOR) of 19.41 (95% CI = 10.39 - 36.25, P < .001) when compared to patients without VF. Median length of stay in arrhythmia group was 5 days compared to 3 days in non-arrhythmia group. Arrhythmias predicting increased LOS included VF (average of 3.63 days longer), AF (average of 0.61 days longer), and AFL (average of 6.95 days longer). Mean total charges of arrhythmia group were $122,503 compared to $76,435 in non-arrhythmia group. Arrhythmias predicting increased total hospitalization charges included VF (increased by an average of $70,572), and AFL (increased by an average of $131,193). Conclusion: About 1/3rd of patients admitted with HOCM had a concomitant diagnosis of arrhythmia. Atrial fibrillation was the most common arrhythmia. Presence of VF was a significant predictor of in-hospital mortality. Presence of VF, AF, AFL increased the LOS, while VF and AFL were associated with increased total hospital charges in patients hospitalized with HOCM.