Prognostic utility of cardiopulmonary exercise testing indices in arrhythmogenic right ventricular cardiomyopathy

Abstract

Abstract Introduction Cardiopulmonary exercise testing (CPET) has an established role in the clinical evaluation of exercise intolerance and in the risk stratification of patients with heart failure. There is limited data assessing its prognostic utility in the evaluation of patients with Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC). The predisposition of patients with ARVC for ventricular arrhythmias and sudden cardiac death has led to recommendations for exercise restrictions and limits our understanding of how the impairment in oxygen extraction and cardiac output impact disease progression and outcomes in these patients. Purpose We examined the association between CPET indices and event free survival (time to mortality or cardiac transplantation) in patients with Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC). Methods Patients with definite ARVC based on 2010 task force criteria and genetically positive were enrolled into our institutional ARVC registry. 43 patients underwent CPET and have been included in our analyses. Indications for testing included: Evaluation of exercise-induced palpitations/arrhythmias or syncope (37%), pharmacotherapy optimization (28%), heart failure evaluation (19%), and ARVC management decisions (16%). CPET data (peak oxygen consumption (pVO2), respiratory exchange ratio (RER), and ventilatory efficiency (VE/VCO2) were assessed in patients at time of initial evaluation. Median follow-up time was 4.9 years (IQR 9 years). Results 126 patients were studied (age 43.7+ 15 yrs; 41% women; LVEF 57+ 11%; 15% with LVEF <50%) and 43 underwent CPET evaluation. 41 patients (95%) performed at near maximal effort (RER >1) and no fatal events were reported during testing. During the follow up period, the outcome (death or cardiac transplantation) occurred in 31 patients. On Kaplan Meier analysis, pVO2 ≤14 mL/kg/min was associated with worse outcomes (unadjusted p<0.001). Peak oxygen consumption (pVO2) ≤14 mL/kg/min and ventilatory efficiency (VE/VCO2) >34 were associated with shorter event free survival (HR 5.58, p=0.002 and HR 5.56 p=0.005, respectively). After adjusting for age, sex, and right ventricular function, the association between peak oxygen consumption (pVO2) and event free survival remained significant (p=0.02). Conclusions In patients with ARVC, peak oxygen consumption (pVO2) was a prognostic indicator of worse outcomes. Our findings suggest a potential role for pVO2 in disease surveillance and early assessment for advanced heart failure therapies. Figure 1. KM plot pVO2 & event free survival Funding Acknowledgement Type of funding source: Other. Main funding source(s): Mayo Clinic