Objective: To use myocardial perfusion imaging to determine the etiology of cocaine-induced chest pain in patients without ECG evidence of acute cardiac ischemia.
Methods: The authors conducted a prospective study of consecutive consenting patients aged 18-70 years with cocaine-induced chest pain who reported cocaine use within three days and presented with a chief complaint of chest pain occurring within three hours and lasting longer than 15 minutes with a normal or nondiagnostic ECG. Patients were excluded if they had a clear-cut noncardiac cause of chest pain, ECG evidence of acute cardiac ischemia, history of myocardial infarction, pregnancy, or lactation, required immediate hospitalization, or were unable to consent. Patients were injected with Tc-99m tetrofosmin and imaged. Perfusion scans were independently read by two nuclear radiologists. Clinicians blinded to scan results determined patient disposition. Patients with abnormal scans were asked to return for follow-up resting scans.
Results: Fourteen patients were enrolled. Twelve of the 14 patients had chest pain at the time of Tc-99m tetrofosmin injection. Ten of the 14 [(71%) 95% CI = 48% to 95%] scans were normal or within normal limits. Four of the 14 [(29%) 95% CI = 5% to 52%] were abnormal. Of the four patients with abnormal scans, two had follow-up scans that demonstrated an irreversible perfusion abnormality, and two who did not return for follow-up reported no subsequent hospitalizations for acute cardiac ischemia.
Conclusion: Perfusion imaging did not demonstrate reversible ischemia in most patients (12/14, 86%) with cocaine-induced chest pain without ECG evidence of ischemia. These results suggest that cocaine-induced chest pain in most patients without ECG evidence of ischemia is not due to acute ischemia.