GENDER DIFFERENCES IN PREDICTORS OF PRIMARY VENTRICULAR FIBRILLATION: RESULTS OF THE PREDESTINATION STUDY

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.

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.

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.

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, p<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).

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.