Introduction: Few studies evaluated risk factors for ventricular fibrillation (VF) before reperfusion during a first acute myocardial infarction (AMI). Important parameters such as blood potassium levels (K+), blood pressure (BP) and heart rate (HR) at presentation were not always considered. Furthermore, the potential for gender differences has never been investigated.
Objectives: To evaluate the presence of gender differences in predictors of primary VF development in the PREDESTINATION (PRimary vEntricular fibrillation and suDden dEath during a firST myocardial iNfArcTION) population.
Patients and methods: PREDESTINATION is a prospective, multicenter, case-control study (matching 1:2 for sex and age) enrolling patients between 18 and 80 years of age with a first AMI, complicated (cases) or not (controls) by primary VF.
Results: 1622 patients were analyzed (average 59 years, 83% male, 35% cases). Comparing male vs female cases, women were older, with lower BMI and lower potassium levels at presentation (3.6 ±0.6 vs 3.8±0.6 mEq/L, p=0.02); they also had a greater prevalence of first degree family history of sudden death (SD), of depression, of physical inactivity, of higher (3-4) TIMI flow in the culprit artery before reperfusion and of VF as first symptom of the AMI (27% vs 15%, p=0.03). The multivariable analysis (logistic regression) performed on the entire population and then only in males identified 9 independent predictors of primary VF, of which 7 risk factors (atrial fibrillation, first K+ <3.5 mEq/L, HR ≥90 bpm, family history of SD, anterior site of the AMI, known hypercholesterolemia, physical inactivity) and two protective factors (known diabetes mellitus and higher systolic BP at presentation). Only 2 factors were confirmed in women: first K+<3.5 (OR 3, 95% CI 1.6-5.8, 0.001) and systolic BP (OR 0.98 per mmHg, 95% CI 0.97-0.99, p=0.02); depression showed a trend for significance. The dose-response correlation coefficient between kaliemia and the probability of primary VF was much more negative in women than in man (figure). Conclusions: the current analysis identified gender differences between cases of primary VF. Only 2 independent predictors of primary VF were found in the female population, with a strong significance of hypokalemia and a much stronger dose-response relationship than in males. These findings aim to start to fill the gap in knowledge of gender specific risk factors for primary VF.
