A Common Tachyarrhythmia In A Rare Myocarditis

Abstract

Giant-cell myocarditis (GCM) is a rare type of myocarditis that is characterized as a rapidly progressive and often fatal myocardial disease. It has a diverse clinical presentation which mimics those of other acquired and genetic cardiomyopathies.This case report highlights ventricular tachycardia (VT) as the initial GCM manifestation and demonstrates a unique case with predominantly right ventricular (RV) involvement.A 45-year-old male presented to the hospital with palpitation and pre-syncope. His past medical history included hyperlipidemia and obstructive sleep apnea. He did not have any significant family or social history. Initial workup was significant for an elevated troponin level of 8.49. His initial ECG showed intermittent VT with left bundle branch with left superior axis at 190 beats-per-minute. Chest X-ray showed mild hilar lymphadenopathy. The patient was admitted and intravenous amiodarone was initiated. Coronary angiography revealed non-obstructive coronary disease. With suppression of VT, repeated ECG showed deep T-wave inversion in leads V1-4. Echocardiogram showed mildly reduced ejection fraction of 40% and dilated and hypokinetic RV. Endobronchial ultrasound-guided subcarinal lymph node was performed to rule out sarcoidosis. Implantable cardioverter defibrillator was placed for secondary prevention of sudden cardiac death. Genetic testing for hereditary forms of cardiomyopathies including arrhythmogenic right ventricular cardiomyopathy (ARVC) was performed. Electroanatomic mapping of the RV showed extensive septal scar which guided sites of biopsy. Biopsy confirmed GCM. Beta-blocker and immunosuppression were started. Patient was transferred to a tertiary care center for transplant evaluation but unfortunately passed away after suffering a major stroke.This case demonstrates challenges related to diagnosis of GCM. Its various clinical presentations overlap with those of more common clinical acute myocardial infarction, sarcoidosis and ARVC. Furthermore, this case underlines the importance of early voltage-map-guided biopsy in diagnosis and treatment of GCM. This is also the first case report of biopsy-proven GCM with predominant RV involvement.