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Background Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited condition associated with ventricular arrhythmias and myocardial dysfunction; however, limited data exist on identifying patients at highest risk. The purpose of the study was to determine whether measures of right ventricular (RV) dysfunction on echocardiogram including RV strain were predictive of structural disease progression in ARVC. Methods and Results A retrospective analysis of serial echocardiograms from 40 patients fulfilling 2010 task force criteria for ARVC was performed to assess structural progression defined by an increase in proximal RV outflow tract dimensions (parasternal short or long axis) or decrease in RV fractional area change. Echocardiograms were analyzed for RV free‐wall peak longitudinal systolic strain using 2‐dimensional speckle tracking. Risk of structural progression and 5‐year change in RV outflow tract measurements were compared with baseline RV strain. Of the 40 ARVC patients, 61% had structural progression with an increase in the mean parasternal short‐axis RV outflow tract dimension from 36.2 to 38.5 mm (P=0.022) and 68% by increase in parasternal long‐axis RV outflow tract dimension from 36.1 to 39.2 mm (P=0.001). RV fractional area change remained stable over time. Baseline RV strain was significantly associated with the risk of structural progression and 5‐year rate of change. Patients with an RV strain more positive than −20% had a higher risk (odds ratio: 18.4; 95% CI, 2.7–125.8; P=0.003) of structural progression. Conclusions RV free wall strain is associated with the rate of structural progression in patients with ARVC. It may be a useful marker in determining which patients require closer follow‐up and treatment.

Background Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is characterized by high arrhythmic burden and progressive heart failure, which can prompt referral for heart transplantation. Cardiopulmonary exercise testing (CPET) has an established role in risk stratification for advanced heart failure therapies, but has not been described in ARVC/D. This study sought to determine the safety and prognostic utility of CPET in patients with ARVC/D. Methods and Results Using the Johns Hopkins ARVC/D Registry, we examined patients with ARVC/D undergoing CPET. Baseline characteristics and transplant‐free survival were compared on the basis of peak oxygen consumption (pVO2) (≤14 or >14 mL/kg per minute) and ventilatory efficiency (Ve/VCO2 slope ≤34 or >34). Thirty‐eight patients underwent 50 CPETs. There were no sustained arrhythmic events. Twenty‐nine patients achieved a maximal test. Patients with pVO2 ≤14 mL/kg per minute were more often men (P=0.042) compared with patients with pVO2 >14 mL/kg per minute. Patients with Ve/VCO2 slope >34 tended to have more moderate/severe right ventricular dilation (7/9 [78%] versus 10/26 [38%]; P=0.060) and clinical heart failure (8/9 [89%] versus 13/26 [50%]; P=0.056) compared with patients with Ve/VCO2 slope ≤34. Patients who underwent heart transplantation were more likely to have clinical heart failure (10/10 [100%] versus 13/28 [46%]; P=0.003). Patients with Ve/VCO2 slope >34 had worse transplant‐free survival compared with patients with Ve/VCO2 slope ≤34 (n=35; hazard ratio, 6.57 [95% CI, 1.28–33.72]; log‐rank P=0.010), whereas transplant‐free survival was similar on the basis of pVO2 groups (n=29; hazard ratio, 3.38 [95% CI, 0.75–15.19]; log‐rank P=0.092). Conclusions CPET is safe to perform in patients with ARVC/D. Ve/VCO2 slope may be used for risk stratification and guide referral for heart transplantation in ARVC/D.

Background Despite growing use of the subcutaneous implantable cardioverter‐defibrillator (S‐ICD), its clinical role in arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) patients remains undefined. We aim to elucidate the cardiac phenotype, implant characteristics, and long‐term efficacy regarding appropriate therapy and complications in ARVC/D patients with an S‐ICD implant. Methods and Results A transatlantic cohort of ARVC/D patients who underwent S‐ICD implantation was analyzed for clinical characteristics, S‐ICD therapy, and long‐term outcome including device‐related complications. The cohort included 29 patients (52% male, 76% probands, 59% with ARVC/D‐associated mutation, 59% primary prevention [no prior sustained ventricular arrhythmias], and 45% first‐generation S‐ICD devices). At implant, all inducible patients (27/29) had conversion of induced ventricular fibrillation. Two patients (7%) had superficial infections of the incision site that were treated conservatively. Over a median follow‐up of 3.16 years (interquartile range: 2.21–4.51 years), all episodes (6 patients, 4% per year) of sustained ventricular arrhythmias were appropriately detected and treated. Six patients (21%) experienced 39 inappropriate shocks, with 3 requiring device explantation. Oversensing of noncardiac signal (n=4; especially myopotentials) and cardiac signal (n=4) was the most frequent etiology. No lead or device dislodgement, infection, skin erosion, or explantation related to need for antitachycardia pacing was noted. Conclusions S‐ICD can effectively treat both induced and spontaneous ventricular arrhythmias in patients with ARVC/D. The rate of inappropriate shocks, although considerable, is comparable to that in ARVC/D patients treated with transvenous ICDs. When they occurred, inappropriate shocks were primarily due to cardiac and, uniquely, noncardiac oversensing. We suggest potential strategies for minimizing inappropriate therapy.

Background Prior studies have shown a close link between exercise and development of arrhythmogenic right ventricular cardiomyopathy. How much exercise restriction reduces ventricular arrhythmia (VA), how genotype modifies its benefit, and whether it reduces risk sufficiently to defer implantable cardioverter‐defibrillator (ICD) placement in arrhythmogenic right ventricular cardiomyopathy are unknown. Methods and Results We interviewed 129 arrhythmogenic right ventricular cardiomyopathy patients (age: 34.0±14.8 years; male: 60%) with ICDs (36% primary prevention) about exercise participation. Exercise change was defined as annual exercise duration and dose in the 3 years before clinical presentation minus that after presentation. The primary outcome was appropriate ICD therapy for VA. During the 5.1 years (interquartile range: 2.7–10.8 years) after presentation, 74% (95/129) patients reduced exercise dose and 85 (66%) patients experienced the primary outcome. In multivariate analyses, top tertile reduction in exercise duration and dose were both associated with less VA (duration: hazard ratio: 0.23 [95% confidence interval, 0.07–0.81]; dose: hazard ratio: 0.14 [95% confidence interval, 0.04–0.44]). Greater reduction in exercise dose conferred greater reduction in VA (P=0.01 for trend). Patients without desmosomal mutations and those with primary‐prevention ICDs benefited more from exercise reduction (P=0.16 and P=0.06 for interaction); however, 58% (18/31) of athletes who reduced exercise dose by >80% still experienced VA. Conclusions Exercise restriction should be recommended to all arrhythmogenic right ventricular cardiomyopathy patients with ICDs. Patients who are “gene‐elusive” and those with primary‐prevention devices may particularly benefit. Exercise reduction is unlikely to reduce arrhythmia sufficiently in high‐risk patients to alter decision‐making regarding ICD implantation.

BackgroundArrhythmogenic right ventricular dysplasia/cardiomyopathy is characterized by ventricular arrhythmias and sudden cardiac death. Once the diagnosis is established, risk stratification to determine whether implantable cardioverter‐defibrillator (ICD) placement is warranted is critical. Methods and ResultsThe cohort included 312 patients (163 men, age at presentation 33.6±13.9 years) with definite arrhythmogenic right ventricular dysplasia/cardiomyopathy who received an ICD. Over 8.8±7.33 years, 186 participants (60%) had appropriate ICD therapy and 58 (19%) had an intervention for ventricular fibrillation/flutter. Ventricular tachycardia at presentation (hazard ratio [HR]: 1.86; 95% confidence interval [CI], 1.38–2.49; P