Prevalence and prognostic significance of ‘J waves’ in patients experiencing ventricular fibrillation during acute coronary syndrome

Abstract

'J waves' have been associated with idiopathic ventricular fibrillation (VF) and have also been described in patients with ischaemic VF. Our aim was to determine whether inferior and/or lateral 'J waves' were associated with the occurrence of VF or in hospital mortality during acute coronary syndrome (ACS). Fifty-three patients (mean age 52 ± 10 years) experienced cardiac arrest due to VF during the first 48 hours of an ACS. These patients were entered in a retrospective case-control study. The control group was matched for age and sex and included 106 patients who experienced an ACS but without VF. 'J waves' were more frequent in the study group than in the control group (62% vs. 39%; P=0.006). 'J waves' (odds ratio [OR] 3.3, 95% confidence interval [CI] 1.5-7.1; P=0.001) and left ventricular ejection fraction<40% (53% vs. 14%; P<0.001) (OR 7.9, 95% CI 3.5-18.0; P=0.001) were associated with VF. Inhospital mortality was 15.1% in the study group versus 0.9% in the control group (OR 18.7, 95% CI 2.2-157.5; P=0.008). VF (OR 18.3, 95% CI 2.3-835.9; P<0.001) and the presence of 'J waves' (OR 15.9. 95% CI 2.4-∞; P<0.001) were predictive of inhospital mortality. In patients who experienced VF, inhospital mortality was 24% when 'J waves' were observed and 0% when 'J waves' were absent (P=0.02). Inferior and lateral 'J waves' were observed more frequently in patients who experienced cardiac arrest due to VF associated with ACS than in the absence of cardiac arrest and were associated with higher inhospital mortality.