Risk factors for primary ventricular fibrillation during acute myocardial infarction: a systematic review and meta-analysis

To evaluate potential risk factors for primary ventricular fibrillation (PVF) during acute myocardial infarction (AMI) by a systematic review and meta-analyses. We searched PubMed for English articles on 'humans' published between 1964 and January 2006 using a validated combination of MESH terms. Twenty-one cohort studies describing 57 158 patients with AMI were analysed. Patients with validated PVF (n=2316) were characterized by an earlier admission (weighted mean difference -2.62 h), male gender [odds ratio (OR 1.27)], smoking (OR 1.26), absence of history of angina (OR for history of angina 0.84), lower heart rate at admission (weighted mean difference -4.02 b.p.m.), ST-segment elevation on admission ECG (OR 3.35), AV conduction block before PVF (OR 2.02), and lower serum potassium at admission (weighted mean difference -0.27 meq/L). Patients with validated PVF developed a larger enzymatic infarct size (standardized mean difference 0.74, P <0.00001). PVF was not associated with a history of myocardial infarction or hypertension. Patients who developed a validated PVF presented with characteristics of both abrupt coronary occlusion and early hospital admission. This review provides no evidence for risk factors for PVF other than ST-elevation and time from onset of symptoms. To find new risk factors, studies should compare validated PVF patients with non-PVF patients who have no signs of heart failure and comparable time delay between onset of symptoms and medical attendance