RESUMO
AIM: To compare the risk of ventricular arrhythmias (VA) and sudden death (SD) between New York Heart Association (NYHA) class I and NYHA class II-III patients with non-ischaemic cardiomyopathy (NICM). METHODS AND RESULTS: Observational retrospective cohort study including patients with NICM who underwent cardiac magnetic resonance at two hospitals. The primary endpoint included appropriate implantable cardioverter defibrillator (ICD) therapies, sustained ventricular tachycardia, resuscitated cardiac arrest and SD. The secondary endpoint included heart failure (HF) hospitalizations, heart transplant, left ventricular assist device implant or HF death. Overall, 698 patients were included, 33% in NYHA class I. During a median follow-up of 31 months, the primary endpoint occurred in 57 patients (8%), with no differences between NYHA class I and NYHA class II-III cases (7% vs. 9%, p = 0.62). Late gadolinium enhancement (LGE) was the only independent predictor of the primary outcome both in NYHA class I and NYHA class II-III patients. LGE+ NYHA class I patients had a similar cumulative incidence of the primary endpoint as compared to LGE+ NYHA class II-III (p = 0.92) and a significantly higher risk as compared to LGE- NYHA class II-III cases (p < 0.001). The risk of the secondary endpoint was significantly higher in patients in NYHA class II-III as compared to those in NYHA class I (hazard ratio 3.2, p = 0.001). CONCLUSIONS: Patients with NICM in NYHA class I are not necessarily at low risk of VA and SD. Actually, LGE+ NYHA class I patients have a high risk. NYHA class I patients with high-risk factors, such as LGE, could benefit from primary prevention ICD at least as much as those in NYHA class II-III with the same risk factors.