USE OF VENTRICULAR PREMATURE COMPLEXES FOR RISK STRATIFICATION AFTER ACUTE MYOCARDIAL-INFARCTION IN THE THROMBOLYTIC ERA

The independent predictive role of ventricular premature complex (VPC) frequency in the stratification of mortality risk after acute myocard ial infarction (AMI) was established in the prethrombolytic era by ext ensive multicenter trials. Thrombolysis has lead to important changes in the natural history of patients after AMI, so that reassessment of established risk factors is now required. The prognostic significance of VPCs was assessed in 680 patients, of whom 379 received early throm bolytic therapy. All patients underwent 24-hour Halter monitoring in a drug-free state between 6 and 10 days after AMI. Patients were follow ed vp for 1 to 8 years. During the first year of follow-up, cardiac de ath occurred in 33 patients, sudden death in 24, and sustained ventric ular tachycardia in 20. Mean VPC frequency was significantly higher in patients who died of cardiac causes, in those who died suddenly, and in those with arrhythmic events during the first year of follow-up. Th is was also true when patients who did and did not undergo thrombolysi s were considered separately. The positive predictive accuracy of VPC frequency in predicting adverse cardiac events was greater in patients who did than did not undergo thrombolysis. At a sensitivity level of 40%, the positive predictive accuracy for cardiac mortality and arrhyt hmic events for the group with thrombolysis was 19.4% and 25.8%, respe ctively, compared with 16% and 16% for those without thrombolysis. Mor eover, the highest VPC frequency for the dichotomy of patients into hi gh- and low-risk groups was 25 VPCs/hour after thrombolysis, but 10 VP Cs/hour for patients without thrombolysis. VPC frequency appears to be more highly predictive of prognosis after AMI in patients who have un dergone thrombolysis than in those who have not, but the optimal frequ ency for dichotomy is higher in the former.