Diagnostic Overlap Between Arrhythmogenic Right Ventricular Dysplasia And Myocarditis

Abstract

Background Arrhythmogenic Right Ventricular Dysplasia (ARVD) is inherited cardiomyopathy with an estimated prevalence of 1 in 5000 people. Case 20 years old male with no PMH had out of hospital cardiac arrest while playing basketball. Bystander CPR was started immediately, and ROSC was achieved after 2 shocks for Vfib. He was intubated immediately on arrival at the nearest ER. A bedside echo showed biventricular failure with LVEF of 5-10%. The patient was taken for an urgent LHC that showed normal coronary arteries. An IABP was placed and he was transferred to our hospital for advanced heart failure therapies. Physical examination was remarkable for intubated and sedated patient with no JVD, and extremities were warm to touch. EKG showed normal sinus rhythm with T wave inversions in V1-V3 lead, normal QTc (Figure 1). He underwent emergent RHC with endomyocardial biopsy which showed RA of 18 mmHg, RV of 36/14 mmHg, PA of 33/18 mmHg, PCWP of 20 mmHg, CO/CI of 2.52/1.24 and PA sat of 48%. Cardiogenic shock conference was initiated, and the decision was made to proceed with VA-ECMO. The biopsy showed inflammatory infiltrate including macrophages, neutrophils, T cells, and focal associated myocyte damage but no giant cells or lymphoid aggregates (Figure 1). This was concerning for acute fulminant myocarditis vs another inflammatory process. He started showing signs of hemodynamic and echocardiographic recovery on day 2 without requiring immunosuppressive medications. VA-ECMO was decannulated on day 3 and extubated on day 4. He was diagnosed as myocarditis and discharged on day 7 with full LVEF recovery but RV remained dilated with reduced function. A cardiac MRI done 1 week later ruled out myocarditis. On follow up visit one month later, he is asymptomatic. His echo shows dyskinetic and dilated RV with PLAX RVOT of 33 mm with normal LV (Figure 1). Genetic testing showed PKP2 mutation. Hence, the diagnosis was ultimately modified to ARVD. He is now referred for an ICD implantation and advised abstinence from competitive sports. Discussion ARVD presents a diagnostic challenge since diseases like myocarditis, sarcoidosis, and dilated cardiomyopathy can act as mimics. Our patient met three major criteria from the 2010 International Task Force Guidelines, including EKG, echo, and genetic mutation; hence meeting requirements for definitive diagnosis of ARVD. ARVD can lead to sudden cardiac death due to ventricular electrical instability. Conclusion ARVD poses diagnostic challenge, a high index of clinical suspicion is required. Initially, ARVD can present similarly to myocarditis on histopathology. VA-ECMO can be utilized as bridge to recovery in critically ill patients with ARVD.