SCMR 22nd Annual Scientific Sessions
Description of Clinical Presentation:
35 years old Caucasian male developed an intense episode of palpitations and dizziness without syncope. He was found to be in sustained monomorphic ventricular tachycardia with a right bundle, right superior axis of over 200 beats per minute upon EMS arrival. Cardioversion was attempted, but failed, and resulted in ventricular fibrillation. He was defibrillated 3 times with resolution to sinus rhythm.
Subsequent coronary angiography and echocardiography were normal. A cardiac MRI (CMR) was ordered.
Diagnostic Techniques and Their Most Important Findings:
CMR was performed on a 1.5T magnet, utilizing 18 mL of Gadavist IV contrast. The right ventricular (RV) myocardium appeared thickened along the inferoseptal wall. Following contrast administration, there was abnormal myocardial delayed enhancement along this portion of the inferoseptal wall at the mid cavity to apex as well as moderately extensive myocardial delayed enhancement along the apex and free wall of the RV. No additional abnormal myocardial delayed enhancement of the left ventricular (LV) myocardium. LV/RV function were normal, with no focal region of abnormal wall motion. Volumetric data for the LV and RV is provided in Table 1.
Learning Points from this Case:
Cardiac sarcoidosis is an uncommon presentation of sarcoidosis - a multisystemic, non-caseating granulomatous disorder.1-4 The LV myocardium is most commonly involved, with some cases affecting both ventricles. Isolated RV involvement, however, is rare.1 RV cardiac sarcoid can show wall thinning, areas of myocardial hypotrophy from infiltration, or fibrofatty replacement.5-6 Though many patients are asymptomatic, some can develop high grade atrioventricular blocks with atrial/ventricular arrhythmias, leading to heart failure or sudden cardiac death.1-5 Areas of infiltration are thought to serve as foci for arrhythmias.3-7 Endomyocardial biopsy is highly specific for cardiac sarcoidosis, though the procedure is invasive and has relatively low sensitivity due to patchy myocardial involvement.1,4 CMR is a validated way to diagnose cardiac sarcoidosis non-invasively. Late gadolinium enhancement within the myocardium can be detected and quantify focal scar and interstitial fibrosis. RV enhancement along with hypertrophy, dilation, and systolic dysfunction bears a worse prognosis.1,2,4,6-8
Our patient demonstrated isolated RV enhancement on CMR. He underwent endomyocardial biopsy, which was unremarkable. Cardiac PET study showed active inflammation within the basal anterior/anteroseptal wall, and the inferior/inferoseptal wall showed mixed active inflammation and fibrosis, corresponding to the areas of enhancement. Additional extracardiac FDG uptake within the perihilar region was also noted. Endobronchial biopsy was positive for non-caseating granulomas consistent with sarcoidosis.
Isolated RV cardiac sarcoidosis, although uncommon, should remain in the differential diagnosis for young patients with conduction abnormalities of unknown etiology, especially in the setting of hypertrophy with patchy enhancement.