Cocaine-associated chest pain: How common is myocardial infarction?

Objective: Prior studies addressing the incidence of acute myocardial infar ction (AMI) in patients with cocaine-associated chest pain have found diver gent results. Previous prospective studies, which found approximately a 6% incidence of AMI, have been criticized for selection bias. This study sough t to determine the rate of AMI in patients with cocaine-associated chest pa in. Methods: All patients seen in an urban university-affiliate hospital be tween July 1996 and February 1998 were identified by ICD-9 medical records search for cocaine use and chest pain/acute coronary syndromes. In this sys tem, all faculty admit all patients with cocaine-associated chest pain for at least 23-hour observation periods. Data collected included demographics, medical and cocaine use history, presenting characteristics, hospital cour se, cardiovascular complications, and diagnostic tests using a 119-item clo sed-question data instrument with high interrater reliability. The main out come measure was AMI according to World Health Organization (WHO) criteria. Results: There were 250 patients identified with a mean age of 33.5 +/- 8. 5 years; 77% were male; 84% were African American. Of 196 patients tested, 185 had cocaine or cocaine metabolites in the urine (94%). The incidence of cardiac risk factors were: hypercholesterolemia, 8%; diabetes, 6%; family history, 34%; hypertension, 26%; tobacco use, 77%; prior MI, 6%; and prior chest pain, 40%. Seventy-seven percent admitted to cocaine use in the prece ding 24 hours: crack, 85%; IV, 2%; nasal, 6%. Twenty-five patients (10%) ha d electrocardiographic evidence of ischemia. A total of 15 patients experie nced an AMI (6%; 95% CI = 4.1% to 8.9%) using WHO criteria. Complications w ere infrequent: bradydysrrhythmias, 0.4%; congestive heart failure, 0.4%; s upraventricular tachycardia, 1.2%; sustained ventricular tachycardia, 0.8%. Conclusion: The incidence of AMI was 6% in patients with cocaine-associate d chest pain. This result is identical to that found in prior prospective s tudies.