Observations from a recently completed homeless women's cohort study indicated that acute intoxication in which cocaine was detected at autopsy was the most common cause of death. This finding follows a national trend of increased overdose deaths. According to the San Francisco Medical Examiner, at least one-third of cocaine-related deaths among San Francisco women are directly linked to a cardiovascular event. While independent influences of both cocaine use and HIV infection on cardiac dysfunction have been described, combined effects and influences from polysubstance use are unclear. Such information could be used to address subclinical cardiac dysfunction prior to infarction and sudden death. Here we propose a multi- disciplinary study to understand the circumstances preceding acute drug-induced cardiovascular events among homeless women. We hypothesize that HIV, polysubstance use and concomitant medications influence chronic drug toxicity and subclinical cardiac injury. To meet our aims, the study will obtain interview data, echocardiograms and specimens for biomarker assessment among 250 homeless and unstably housed women (125 HIV+ and 125 HIV-). Results from the proposed study will provide enhanced clinical tools for risk assessment and risk stratification among cocaine users, as well as clarify endpoints for future pharmacological and behavioral interventions.