CARDIAC COMPLICATIONS OF COCAINE ABUSE

Cardiac complications of cocaine abuse and a rational approach to eval uating and managing them are described. Cardiac abnormalities reported among asymptomatic cocaine abusers include echocardiographic left ven tricular hypertrophy and segmental wall motion abnormalities. Electroc ardiogram may reveal increased QRS voltage, ST-T changes, and patholog ic Q waves. Episodes of ST elevation may be seen during Holter monitor ing. The management of cocaine-abusing patients who present to an emer gency room with acute chest pain is controversial because the two repo rted studies yielded conflicting results regarding the incidence of my ocardial infarction (MI). Even in the absence of infarction, electroca rdiographic abnormalities are common among these patients, which compl icates the decision-making regarding hospitalization. Pathophysiology of cocaine-related MI is discussed. Distinct clinical features of coca ine-related MI make it clear that the association between the two is n ot just temporal. However, considering the number of persons abusing c ocaine, it is a rarity. Beta-adrenergic blockers should be avoided in the treatment of cocaine-induced myocardial ischemia which is best tre ated with nitrates and calcium-channel blockers. Reports of cocaine-in duced myocarditis and cardiomyopathy are reviewed. Experimental studie s and clinical case reports suggest that cocaine may cause lethal arrh ythmias. Cocaine prolongs repolarization by a depressant effect on pot assium current and may generate early afterdepolarizations. It is poss ible that cocaine-associated arrhythmias are secondary to vasospasm-re lated ischemia and reperfusion as well.