Risk of ventricular arrhythmia in patients with myocardial infarction and non-obstructive coronary arteries and normal ejection fraction.

Aim: To assess the arrhythmic determinants and prognosis of patients presenting with myocardial infarction and non-obstructive coronary arteries (MINOCA) with normal ejection fraction (EF).

Methods: This is an observational analysis of 131 MINOCA patients with normal EF. Three cardiac magnetic resonance (CMR) diagnosis classes were recognized according to the late gadolinium enhancement (LGE) pattern: Myocardial infarction (MI) ( = 34), myocarditis ( = 47), and "no LGE" ( = 50). Ventricular events occurring during hospitalization were recorded and the entire population was followed-up at 1 year.

Results: Ventricular arrhythmia was observed in 18 (13.8%) patients during hospitalization. The "no LGE" patients experienced fewer ventricular events than the MI and myocarditis patients [4.0% 26.5% and 14.9%, respectively ( = 0.013)]. There was no significant difference between the MI and myocarditis groups. On multivariate analysis, LGE transmural extent [OR = 1.52 (1.08-2.15), = 0.017] and ST-segment elevation [OR = 4.65 (1.61-13.40), = 0.004] were independent predictors of ventricular arrhythmic events, irrespective of the diagnosis class. Finally, no patient experienced sudden cardiac death or ventricular arrhythmia recurrence at 1-year.

Conclusion: MINOCA patients with normal EF presented no 1-year cardiovascular events, irrespective of the CMR diagnosis class. LGE transmural extent and ST segment elevation at admission are risk markers of ventricular arrhythmia during hospitalization.