Giant Cell Myocarditis Mimicking Idiopathic Fascicular Ventricular Tachycardia

Incidence, Risk Factors, and Outcome of Life-Threatening Ventricular Arrhythmias in Giant Cell Myocarditis

Background—

Ventricular tachyarrhythmias are characteristic of giant cell myocarditis, but their true incidence, predictors, and outcome are unknown.

Methods and Results—

Our work involved 51 patients with giant cell myocarditis (35 women) aged 52±12 years. Their medical records were reviewed for history, results of laboratory and imaging studies, and occurrence of serious cardiac events, including life-threatening ventricular tachyarrhythmias. Sudden cardiac death (fatal or aborted) was the primary end point of our analyses, whereas the composite of sudden cardiac death and ventricular tachycardia requiring treatment constituted the secondary end point. Giant cell myocarditis presented as nonfatal ventricular tachyarrhythmia in 10 patients and as a fatal cardiac arrest in 1 patient. Overall, 14 of 50 patients suffered a sudden cardiac death during follow-up, with a cumulative incidence of 22% at 1 year and 26% at 5 years from presentation. The composite incidence of sudden cardiac death or ventricular tachycardia was 41% at 1 year and 55% at 5 years. The incidence of arrhythmias was associated with high plasma concentrations of troponin-T and N-terminal brain natriuretic propeptide, as well as with moderate-to-severe fibrosis on myocardial biopsy and history of ventricular tachyarrhythmias at presentation ( P <0.05 for all). An intracardiac cardioverter defibrillator was implanted in 31 patients, of whom 17 had altogether 114 appropriate antiarrhythmic therapies by the device and none suffered an arrhythmic death.

Conclusions—

In giant cell myocarditis, the risk of life-threatening ventricular arrhythmias exceeds 50% at 5 years from admission, being related to the presenting clinical manifestation and markers of myocardial injury and scarring.

Markedly Elevated Cardiac Bio-Markers at Presentation With Normal Ventricular Function: A Novel Clinical Subset of Myocarditis Manifestation

We present a case of a 19-year-old woman with myocarditis who had significantly elevated cardiac markers at presentation even before any myocardial damage ensued. The patient had complicated clinical course with ventricular arrhythmia and cardiac arrest requiring resuscitation but eventually recovered completely. Though there is limited information available regarding such cases, the significantly elevated initial cardiac markers in the absence of left ventricular decompensation may probably represent a clinical subset of myocarditis and may portend an impending complicated clinical course. Further systematic research is required to define the clinical phenotype and elucidate underlying mechanisms.

Giant cell myocarditis with incessant ventricular arrhythmias treated successfully with methylprednisolone and rat antithymocyte globulin

Giant cell myocarditis is an aggressive form of this condition that is typically progressive and unresponsive to usual medical treatment. Here, we describe a 34-year-old patient presenting with incessant ventricular arrhythmias with hemodynamic compromise who required prolonged support in intensive care with an intra-aortic balloon pump (IABP). His Coronary arteries were normal and LV endomyocardial biopsy revealed myocyte necrosis with inflammatory infiltrate of lymphocytes, eosinophils, and giant cells suggestive of giant cell myocarditis. He was successfully treated with pulsed intravenous methylprednisolone and rat antithymocyte globulin (RATG). Despite a good functional cardiac recovery, some months later he developed a fluctuant neck swelling which fine needle aspiration confirmed as tuberculosis.