domingo, 4 de janeiro de 2009

Ventricular arrhythmias herald poor outcomes in ACS patients

MedWire News: Ventricular arrhythmias (VA) in patients hospitalized with acute coronary syndromes (ACS) have become less common in recent years but remain a strong predictor of increased mortality, research shows. 


The finding is based on an analysis of 52,380 patients with ACS enrolled in the Global Registry of Acute Coronary Events between 1999 and 2005.

Álvaro Avezum (University of São Paolo, Brazil) and colleagues found that the incidence of in-hospital VA fell steadily over time, from 8.0% in 1999 to 7.0% in 2002 and 5.8% in 2005 (p<0.001). The decrease was driven by a decline in the incidence of ventricular fibrillation/cardiac arrest, whereas the incidence of ventricular tachycardia showed little change over time.

VA was associated with an extremely high risk for death, the authors report. In-hospital case-fatality rates were 52% among patients with VA versus 1.6% in those without (odds ratio [OR] 46.4). The increased mortality risk persisted at 6 months after discharge, although with a reduced OR of 1.32.

In multivariable analysis, ST-segment deviation, Killip class, age, initial cardiac markers, serum creatinine, heart rate, and smoking history were all associated with an increased the risk for VA, whereas prior myocardial infarction and percutaneous coronary intervention were associated with a reduced risk.

Writing in the American Journal of Cardiology, Avezum and fellow investigators note that ACS patients with in-hospital VA had a higher-risk profile than those without, suggesting that such patients might be targeted for preventive measures.

They hypothesize that VA during the first days of hospitalization for ACS may be related to “electrical irritability” associated with ischemic injury, and conclude: “Therapies that prevent the development of this arrhythmogenic substrate by improving left ventricular function should be considered in this clinical setting.”

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