CardioNerds (Amit Goyal & Daniel Ambinder) join Summa Health cardiology fellows (Jack Hornick, Phoo Pwint Nandar, and Sideris Facaros) for a hike on the Towpath Trail at Cuyahoga Valley National Park in Akron, Ohio! They discuss an informative case of Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) complicated by ventricular tachycardia & cardiogenic shock. Dr. Kenneth Varian provides the E-CPR and program director, Dr. Marc Penn provides a message for applicants. Episode notes were developed by Johns Hopkins internal medicine resident, Eunice Dugan, with mentorship from University of Maryland cardiology fellow Karan Desai.
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Episode graphic by Dr. Carine Hamo
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Patient Summary
A female in her 40s with no past medical history presented 6 years prior with acute onset dizziness, palpitations and fatigue without chest pain. She had no family history of arrythmias, SCD, or prior syncope. Her heart rate was 170 bpm and EKG showed wide complex, regular tachycardia felt to be VT. She underwent synchronized cardioversion to sinus rhythm. Her baseline EKG showed sinus bradycardia with low voltage, incomplete RBBB, and ventricular ectopy. Labs were unrevealing, and social history was negative for toxic insults or illicit substance abuse. TTE showed preserved LVEF and normal valves, but RV was dilated with decreased systolic function. LHC was without obstructive coronary disease. She was diagnosed with ARVC and received an ICD for secondary prevention. She was discharged on sotalol for arrythmia management. Her genetic testing later returned positive for uncertain significance in the DSP gene and JUP gene, both commonly implicated in ARVC. She was followed in the outpatient setting for 5 years with no apparent shocks. Six years later, she presented with acute onset dizziness and palpitations similar to her initial presentation. EKG showed a wide complex tachycardia at 170 bpm treated with amiodarone and cardioversion. On ICD interrogation, she was found to have had several episodes of VT, but at a rates below the VT detection zone programmed in the ICD. Subsequent RHC showed significantly depressed cardiac index and RV dysfunction. She underwent successful inpatient VT ablation. She was then discharged home with plans for close follow up; however, 2 days later, she started feeling nauseous with fatigue and abdominal pain. She was sent straight to the nearest transplant-capable hospital where she was found to be in cardiogenic shock. She was admitted to ICU and started on inotropes. Due to refractory shock, she was cannulated for VA ECMO and successfully underwent cardiac transplantation two days later.
Case Media
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A. Post cardioversion ECG: NSR, low voltage, incomplete RBBB, PVCB. TTE: RV enlargement C. TTE: Tissue Doppler velocity (S') low
TEE
Episode Schematics & Teaching
The CardioNerds 5! – 5 major takeaways from the #CNCR case
What is ARVC?
Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia (ARVC/D) is a heritable cardiac muscle disorder that classically involves the RV (though LV involvement is increasingly being recognized) marked by loss of healthy myocardium and replacement with fibrofatty tissue predominantly due to genetic defects in both desmosomal and non-desmosomal proteins. Clinical manifestations include RV dysfunction, ventricular arrhythmias, and sudden cardiac death (SCD). This is a progressive disease that can affect the epicardium and/or mid-myocardium first and then move towards the sub-endocardium. It affects approximately 1 in 5000 individuals and is an important cause of (SCD) in young patients. 50% of patients have a positive family history and it is thought to be inherit in an autosomal dominant fashion, however prevalence is underestimated due to incomplete penetrance. Interestingly, males are more affected than females possibly due to interaction of sex hormones with pathophysiology or historically different levels of participation in competitive sports among men and women. The differential for ARVC should include Uhl's anomaly, myocarditis, sarcoidosis, and Brugada syndrome among other considerations.
What genes are implicated and what is the pathophysiology?
While 20-30% of ARVC is due to non-desmosomal gene variants (e.g., desmin, Titin) and non-genetic causes, 40-50% is due to autosomal dominant gene mutations that encode desmosomal proteins. These include plakophilin 2 PKP2 (in 10 to 45% of patients), followed by desmoplakin DSP (10 to 15%), desmoglein 2 DSG2 (7 to 10%), and desmocollin 2 DSC2 (2%). Rarely, there can be an autosomal recessive inheritance pattern, inclu