Prognostic role of NYHA class in heart failure patients undergoing primary prevention ICD therapy

AIMS: Concerns about the prognostic value of NYHA functional class (FC) in heart failure (HF) patients carrying a prophylactic implantable cardioverter defibrillator (ICD) are still present. We aimed to compare whether mortality and arrhythmic risk were different, in a cohort of HF patients undergoing ICD‐only implant, according to their FC. METHODS AND RESULTS: HF patients with left ventricle ejection fraction (LVEF) ≤35%, undergoing first prophylactic ICD‐only implant were collected from a multicentre nationwide registry (2006–2015). Six hundred and twenty‐one patients were identified (101 patients in NYHA I; 411 in NYHA II; 109 in NYHA III). After a mean follow‐up of 4.4 years (±2.1), 126 patients died (20.3%). All‐cause mortality risk was higher in symptomatic patients: 13.9% in NYHA I patients, 18.3% in NYHA II patients (HR: 1.8, 95% CI 1.1–3.2), and 32.9% in NYHA III patients (HR: 3.9, 95% CI 2.1–7.3). Seventy‐eight out of all deaths were due to cardiovascular causes (12.6%). Cardiovascular mortality risk was also higher in symptomatic patients: 6.9% in NYHA I patients, 11% in NYHA II patients (HR: 2.2, 95% CI 1.1–4.9), and 23.9% in NYHA III (HR: 5.5, 95% CI 2.4–12.7). One hundred and seventeen patients received a first appropriate ICD therapy (19.4%). Arrhythmia free survival did not differ among study groups [20.8% in NYHA I patients, 18.7% in NYHA II (HR: 1.1, 95% CI 0.6–1.7) and 20.8% in NYHA III patients (HR: 1.3, 95% CI 0.7–2.5)]. NYHA class independently predicted cardiovascular mortality (NYHA III vs. NYHA I: HR, 4.7; 95% CI, 1.7–12.8, P = 0.002; NYHA II vs. NYHA I: HR, 2.1, 95% CI, 1.0–5.6, P = 0.05) but not all‐cause death (NYHA III vs. NYHA I: HR: 1.8, 95% CI 0.8–3.9, P = 0.11; NYHA II vs. NYHA I: HR, 1.1, 95% CI 0.6–2.2, P = 0.71;). Atrial fibrillation, chronic kidney disease, and diabetes emerged as predictors of both all‐cause death [(HR: 1.8, 95% CI 1.2–2.8, P = 0.005), (HR: 2.2, 95% CI 1.4–3.4, P < 0.001), (HR: 2.0, 95% CI 1.3–3.1, P = 0.001), respectively] and cardiovascular mortality [(HR: 1.8, 95% CI 1.1–3.1, P = 0.02), (HR: 3.1, 95% CI 1.8–5.4, P < 0.001), (HR: 1.7, 95% CI 1.1–3, P = 0.032), respectively]. CONCLUSIONS: Mortality in HF patients undergoing prophylactic ICD implantation was higher in symptomatic patients. NYHA functional class along with other comorbidities might be helpful to identify a subgroup of ICD carriers with poorer prognosis and higher risk of cardiovascular death.