Impact of late ventricular fibrillation on postdischarge 1-year mortality of patients presenting with acute myocardial infarction: a nationwide retrospective study

Objective To assess the impact of in-hospital late ventricular fibrillation (VF) (>48hours) on the 1-year mortality risk among patients presenting with acute myocardial infarction (AMI) who survived the index hospitalisation. Design Retrospective cohort study estimating the incidence rates of late VF following AMI and the associated 1-year risk of all-cause mortality. Setting Cardiac intensive care units (CICUs) in Israel between the years 2000 and 2018. Participants Patients presenting with AMI (ST-segment elevation MI (STEMI) and non-ST-segment elevation MI (NSTEMI)) who were admitted to CICUs. Results A total of 14280 consecutive AMI patients of whom 118 developed late VF and 68 of these survived the index hospitalisation. Patients with late VF had higher mortality rates within 1 year following AMI overall (54.8% vs 10.2%, p<0.01), among STEMI patients (54.7% vs 10%, p<0.01) and among those with NSTEMI (55.2% vs 10.5%, p<0.01). Late VF post-MI was found associated with increased risk of 1-year mortality (adjusted HR (aHR) 3.25, 95% CI (1.98 to 5.34), p<0.01). While this association was statistically significant among STEMI patients (aHR 3.6, 95%CI (2.06 to 6.30), p<0.01), it was not statistically significant among NSTEMI patients (aHR=1.87, 95%CI (0.6 to 5.84), p=0.29). Conclusions Late VF was found to be associated with increased 1-year mortality risk among patients presenting with AMI. However, this association was only significant among STEMI patients, but not NSTEMI patients.