Risk factors for primary ventricular fibrillation during a first myocardial infarction: Clinical findings from PREDESTINATION (PRimary vEntricular fibrillation and suDden dEath during firST myocardIal iNfArcTION).

Background: Few studies prospectively assessed risk factors for ventricular fibrillation (VF) during a first myocardial infarction (MI). We designed a nation-wide study aiming to identify clinical and genetic characteristics associated with primary VF; and report here about clinical features.

Methods: PREDESTINATION (PRimary vEntricular fibrillation and suDden dEath during a firST myocardIal iNfArcTION) is an Italian case-control, prospective multicentre study. Cases are patients aged 18-80 years with a first MI and at least one VF episodes occurring within 24 h of symptoms onset, before reperfusion. Cases and controls are paired 1: 2 by gender and age (±5 years).

Results: Among 1026 patients enrolled between 2007 and 2017, 970 entered the primary analysis: 375 cases and 595 controls (mean age 59 years, 85% males). Multivariable analysis identified 5 independent predictors of primary VF: systolic blood pressure (OR 0.982, 95% CI: 0.98-0.99 for each mm Hg) and K levels <3.5 mEq/L at presentation (OR 2.28, 95% CI: 1.6-3.3), family history of sudden death (OR 1.80, 95% CI: 1.1-3.0), physical inactivity (OR 1.73, 95% CI: 1.1-2.8) and anterior MI (OR 1.52, 95% CI: 1.1-2.1). Excluding K levels obtained after VF, the OR associated with K levels <3.5 mEq/L was1.99 (95 CI 1.22-3.21).

Conclusions: The present study identified 5 independent predictors of primary VF: familiarity, anterior MI, low systolic blood pressure, physical inactivity and hypokalaemia. Importantly, the last two risk factors are modifiable and, especially in the presence of a family history of sudden death, they should be avoided as much as possible.