Cardiopulmonary exercise testing may not predict appropriate implantable cardioverter defibrillator therapies in heart failure patients.

Background: The prognostic value of cardiopulmonary exercise testing (CPET) variables for major cardiovascular events in patients with heart failure (HF) is widely established. However, the prognostic value of these variables as predictors of appropriate implantable cardioverter-defibrillator (ICD) therapies has not been sufficiently well addressed. This study aimed to evaluate CPET variables such as peak oxygen uptake (VO2 peak), relationship between change in minute ventilation (VE) and carbon dioxide output (VCO2 ) during incremental exercise (VE/VCO2 slope) and exercise-related periodic breathing (EPB) as appropriate ICD therapy predictors in HF patients. Methods: We retrospectively assessed 61 HF patients who underwent CPET and had ICD implanted for primary prevention. Patients were followed for 767 ± 601 days. Primary outcome was appropriate ICD-delivered therapy, either anti-tachycardia pacing (ATP) or shock. Results: The sample consisted mostly of male patients (65.6%), with severe ventricular dysfunction (mean left ventricular ejection fraction (LVEF) 27 ± 6%). The primary outcome occurred in 20 patients (32%). There were no significant differences in VO2 peak (17.7 ± 4.1 and 16.9 ± 4.5 mL/kg/min), VE/VCO2 slope (39.7 ± 8.4 and 39.6 ± 10.2) or EPB prevalence (20% and 19.5%) in patients with or without appropriate ICD therapy. According to Cox regression analysis, none of the CPET variables were significant predictors of appropriate ICD therapy. Conclusions: In this cohort study of HF patients, CPET variables did not predict appropriate ICD therapies. Further studies with large number of patients are warranted to address this issue.