Background Ventricular arrhythmias (VA), including ventricular tachycardia and ventricular fibrillation, are the most common remediable cause of death in patients with acute myocardial infarction. Augmented sympathetic neural activity to the heart and myocardial catecholamine release may be the primary factors in the generation of VA. The aim of this study was to assess the predictive value of salivary α-amylase (sAA) activity, an indicator of sympathetic activity, for malignant VA occurrence and for short-term outcome in patients with ST-segment elevation myocardial infarction (STEMI).

Methods Patients with STEMI (n=91) were recruited from the Emergency Department during the period 1 December 2008 to 31 April 2010. Correlations of initial sAA activity at presentation with VA, as well as 1-month prognosis were analysed.

Results sAA activity was significantly increased in the VA group (395±173.7; n=9) as compared with the non-VA group (283±89.3; n=82) (p=0.014). The adjusted OR for malignant ventricular arrhythmia occurrence was 1.010 (95% CI 1.001 to 1.018). Eight patients (8.8%) died and 24 (26.4%) had at least one short-term adverse event within the first month after STEMI. Simple logistic regression analysis showed that sAA is an independent predictor for short-term prognosis (p=0.049, OR 1.005, 95% CI 1.000 to 1.009).

Conclusions Although a prospective study with a large cohort is required, the present results suggest that high initial sAA activity is associated with increased risk of malignant VA and predicts short-term prognosis in patients with STEMI.