Complete Heart Block and Syncope: A Rare Presentation of Mixed Lymphocytic and Giant Cell Myocarditis

Introduction Mixed lymphocytic and giant cell myocarditis is a rare devastating disease with a very high mortality rate. Case report A 59 year old male with no known past medical history presented with syncope. Electrocardiogram revealed complete heart block and a permanent pacemaker was placed. Cardiac MRI showed increased T2 signal in the basal septum with a normal left ventricular ejection fraction. Nine months later, the patient presented with shortness of breath unresponsive to outpatient antibiotics and bronchodilators. They were found to be in cardiogenic shock which required inotropic support. Pulse steroids were administered for presumed inflammatory cardiomyopathy. Right heart catheterization confirmed cardiogenic shock. An endomyocardial biopsy was performed. There was development of frequent episodes of ventricular tachycardia despite antiarrhythmic infusions and attempts to electrically pace the patient out of the rhythm. V-A ECMO and an intra-aortic balloon pump were inserted for mechanical support. An impella was placed on the right for right-ventricular support. The patient developed worsening cardiogenic shock leading to watershed infarcts of the brain and acute liver and kidney failure. The patient was determined to not be transplant candidate and the family decided to move care to comfort directed measures and expired. Results Post-mortem autopsy showed mixed lymphocytic and giant cell myocarditis. Lymphoid aggregates were composed of mature lymphocytes. Conclusions Initial presentation of lymphocytic or giant cell myocarditis is congestive heart failure and or ventricular arrhythmias. Survival rates without transplantation are extremely low. This case presents a patient with complete heart block as a result of mixed lymphocytic and giant cell myocarditis. It highlights the importance of early diagnosis with cardiac biopsy to allow for early bridge to transplant with mechanical circulatory assist devices in a disease state that has a very high mortality rate. Figure 1