137 - QRS Voltage Increases during Recovery from Fulminant Myocarditis

Abstract

Introduction: Fulminant myocarditis is a rare subclass of lymphocytic myocarditis known to have a favorable long-term prognosis if the patient survives the acute illness. The evolution of electrocardiograms (ECGs) in fulminant myocarditis has not been well described. Hypothesis: Improvement in QRS voltage correlates with clinical and echocardiographic recovery from fulminant myocarditis. Methods: A single-center retrospective analysis was conducted in all patients who underwent endomyocardial biopsy. Patients met the inclusion criteria as fulminant myocarditis if: (1) biopsy result met Dallas criteria for lymphocytic myocarditis, (2) mechanical circulatory support (MCS) or high-dose inotrope or vasopressor infusion was required, and (3) symptom onset was heralded by febrile illness. 12-lead ECGs and echocardiograms during the acute and recovery phases were reviewed. Recovery was defined as normalization of left ventricular function or discontinuation of MCS and vasoactive medications due to clinical improvement. Low voltage was defined as a maximum QRS amplitude <0.5 mV in all limb leads. Result: Seven patients met the inclusion criteria. Three patients required ECMO support and one patient needed support with an IABP. None of the patients received immunosuppression. The interval between initial ECG and recovery phase ECG was 9.6 ± 4.3 days. All patients met the criteria for low voltage during the acute phase. Maximum QRS amplitude in the limb leads during the acute phase was 0.32 ± 0.08 mV and increased to 0.74 ± 0.24 mV (P = .001) during the recovery phase. The sum of all 12 QRS amplitudes during the acute phase was 5.13 ± 0.96 mV and increased to 8.14 ± 1.68 mV (P = .001) during the recovery phase. Ejection fraction was 31 ± 6% during the acute phase and improved to 52 ± 11% (P = .001) during the recovery phase. There was a downward trend of septal thickness from 0.98 ± 0.15 cm to 0.84 ± 0.07 cm (P = .056) during the recovery, while left ventricular diastolic dimension remained unchanged (P = .77). None of the patients had a significant pericardial effusion. Conclusion: Low QRS voltage was observed in patients with fulminant myocarditis. Increase in QRS voltage parallels the improvement in ejection fraction and ventricular wall inflammation.