Occurrence and predictors of severe arrhythmia in patients with myocarditis

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. Background/Introduction Patients with myocarditis are at risk for severe, life-threatening arrhythmia. However, predictors to identify high-risk patients are lacking. Purpose We investigated the occurrence and potential risk factors of severe arrhythmia in myocarditis patients. Methods 212 myocarditis patients that were hospitalized for arrhythmia monitoring at a tertiary university hospital were retrospectively enrolled. Non-sustained ventricular tachycardia (VT), sustained VT, ventricular fibrillation or cardiac arrest were considered as severe arrhythmia. We used a stepwise logistic regression model to investigate potential predictors. These included age, sex, clinical presentation (chest pain, palpitations, dyspnea, syncope, cardiac murmur, edema, pericardial friction, arrhythmia at presentation, Killip-class), comorbidities (hypertension, diabetes, coronary heart disease), imaging parameters (left ventricular ejection fraction [LVEF], pericardial effusion, edema and LGE on MRI), ECG variables (PQ depression, ST elevation, ST depression) and maximum levels of blood biomarkers (CRP, leukocytes, Troponin T, CK-MB). Results Mean age was 40.8 years, 73.1% were male and mean LVEF was 52.9%. During the hospital stay, 40 (18.9%) patients experienced severe arrhythmia: 33 (15.6%) non-sustained VT, 9 (4.2%) sustained VT, 1 (0.5%) ventricular fibrillation and 3 (1.4%) cardiac arrests (arrhythmia not mutually exclusive). Most arrhythmia occurred in the first 72h of monitoring (Figure). Significant predictors selected by the stepwise model (OR [95% CI]) for severe arrhythmia were LVEF (per 1% increase 0.95 [0.92; 0.99], p=0.005), syncope at presentation (7.9 [1.5; 40.4], p=0.01), any arrhythmia at first presentation (6.5 [1.3; 32.7], p=0.02) and CK-MB (per 10-unit increase 1.2 [1.1; 1.3], p=0.001). Conclusion(s) Myocarditis patients with low LVEF, presenting with arrhythmia and syncope and with increased CK-MB are at increased risk for severe arrhythmia and should be closely monitored. Further studies are needed to define, if patients without these risk factors might be safely discharged early.