Cardiac manifestations of cocaine abuse: a cross-sectional study of asymptomatic men with a history of long-term abuse of "crack" cocaine

Echocardiographic Findings in Heart Failure Patients With Methamphetamine Use: A Case-Control Study

Background

Methamphetamine use is associated with cardiovascular disease and significant morbidity and mortality. There is only one previous study performed on echocardiographic parameters in patients with methamphetamine cardiomyopathy.

Methods

We performed a retrospective review of medical records in a county hospital in Southern California with a high population of methamphetamine users. We reviewed medical records and echocardiogram findings in patients seen in our institution from November 2019 to November 2020 who had cardiomyopathy with and without methamphetamine use. We excluded patients who either left the hospital or expired before appropriate assessment. We divided our patient population into a case group (methamphetamine users) and a control group (non-methamphetamine users) to study and compare their echocardiographic parameters.

Results

Case group included a total of 254 patients and control group included 268 patients. Majority of the patient population were males - 178 (70%) and 180 (67%) in the case and control group respectively. Age was found to be statistically significant with the younger population in the case group (p = 0.0000). Our analysis revealed statistically significant difference in methamphetamine users compared to non-users in regards to left ventricle ejection fraction (33.65% ± 18.02 vs. 41.55% ± 15.61, p=0.0000), left ventricle mass index (122.49 grams/m² ± 40.66 vs. 108.62 grams/m² ± 32.82, p=0.0000), left ventricle end diastolic volume index (85.91 mL/m² ± 37.40 vs. 72.44 mL/m² ± 25.44; p=0.0000) and marginally significant right ventricle systolic pressure (42.29mmHg ± 17.53 vs. 39.59mmHg ± 15.61; p=0.0540)

Conclusion

Our results indicated that methamphetamine users had echocardiogram findings with decreased ejection fraction and increased left ventricular mass index, end-diastolic volume index, and right ventricular systolic pressure consistent with worse dilated cardiomyopathy comparison to non-users.

Characteristics, trends, outcomes, and costs of stimulant-related acute heart failure hospitalizations in the United States

BACKGROUND

Heart failure (HF) hospitalizations remains a significant burden on the health care system. Stimulants including cocaine, amphetamine and its derivatives are amongst the most used illegal substances in the United States. The information regarding stimulant-related HF hospitalizations is scarce. We sought to evaluate the characteristics and trends of stimulant-related HF hospitalizations in the United States and their associated outcomes and resource utilization.

METHODS

Using the National Inpatient Sample (NIS), we identified patients with a primary diagnosis of HF hospitalization. These hospitalizations were further divided into those with and without a concomitant diagnosis of stimulant (cocaine or amphetamine) dependence or abuse. Survey specific techniques were employed to compare trends in baseline characteristics, complications, procedures, outcomes and resource utilization between the two cohorts.

RESULTS

We identified 9,932,753 hospitalizations (weighted) with a primary diagnosis of heart failure, of those 138,438 (1.39%) had a diagnosis of active stimulant use. The proportion of stimulant-related HF hospitalization is on the rise (1.1% to 1.9%). Stimulant-related HF hospitalization was highest amongst age group 30-39 years and 7.9% of HF hospitalizations in this age group were due to stimulant use. The proportion of stimulant-related HF hospitalization for the White and Hispanic race has doubled from 2008 to 2017. Stimulant-related HF hospitalization is associated with increased incidence of in-hospital complications like cardiogenic shock, acute kidney injury and ventricular tachycardia. These patients have more than 7-fold higher discharge against medical advice.

CONCLUSIONS

Stimulant-related HF hospitalizations have been increasing. It is associate with significant morbidity burden and health care utilization.

Cocaine, cardiomyopathy, and heart failure: a systematic review and meta-analysis

Although the cardiotoxic effects of cocaine are universally recognized, the association between cocaine and cardiomyopathy and/or heart failure is poorly understood. To conduct a comprehensive review and meta-analysis on the association between cocaine, heart failure, and cardiomyopathy, we first conducted a broad-term search in PubMed, Embase, Web of Science, and Scopus for human studies containing primary data on the relationship between cocaine and heart failure or cardiomyopathy. We were interested in studies with data beyond acute coronary syndromes. Retrieved studies were grouped into different categories based on possible hypotheses to test by meta-analysis. A second search with specific terms was then conducted. For grouped studies with sufficient clinical and methodological homogeneity, effect sizes were calculated and combined for meta-analysis by the Random Effects model. There is in general a need for more primary data studies that investigate heart failure and/or cardiomyopathy in cocaine users for mechanisms independent of ischemia. There were, however, enough studies to combine by meta-analyses that showed that chronic cocaine use is associated with anatomical and functional changes more consistent with diastolic heart failure instead of the commonly taught dilated cardiomyopathy pathway. In patients without a history of ACS, chronic cocaine use was not associated with significantly reduced EF. The few studies on acute cocaine had conflicting results on whether single-dose intravascular cocaine results in acute heart failure. Studies identified that included beta-blockade therapy in cocaine users with cardiac disease suggest that beta-blockers are not unsafe and that may be effective in the treatment of cocaine-associated heart failure. Chronic cocaine use is associated with anatomical and physiological changes of the heart muscle that are potentially reversible with beta-blockade therapy.

A Rare Case of Second Degree Mobitz Type II AV Block Associated with Cocaine Use

Cocaine is a commonly abused illicit drug in the United States. The complex effects of cocaine on the conduction system of the human heart has not been completely understood. Cocaine acts as a sympathomimetic by inhibition of reuptake of neuronal catecholamines, leading mostly to tachyarrhythmias on presentation. However, cocaine also exerts other effects on the conduction system including sympathomimetic, sino-bradycardic as well as local anesthetic properties. While Multiple cases of atrioventricular (AV) conduction blocks including first degree AV block, Mobitz type I and third degree AV blocks have been previously reported, we hereby present the first case report of cocaine- induced Mobitz type II second degree AV block. This case occurred in a 55 year old woman who presented with retrosternal chest pressure and tested positive for cocaine abuse as documented by urine toxicology test. Patient spontaneously converted to normal sinus rhythm the following day post admission to the hospital. Cocaine is known to inhibit sodium channels and thus has been known to decrease SA node automaticity and conduction via AV node. Electrophysiology studies have previously confirmed cocaine mediated delay in impulse conduction and repolarization. Though rare, physicians should be aware of the possibility of bradyarrhythmias associated with cocaine abuse in order to apply standard therapy such as pacemaker in the event of non-resolution of this serious arrhythmia.

Vascular disease in cocaine addiction

Cocaine, a powerful vasoconstrictor, induces immune responses including cytokine elevations. Chronic cocaine use is associated with functional brain impairments potentially mediated by vascular pathology. Although the Crack-Cocaine epidemic has declined, its vascular consequences are increasingly becoming evident among individuals with cocaine use disorder of that period, now aging. Paradoxically, during the period when prevention efforts could make a difference, this population receives psychosocial treatment at best. We review major postmortem and in vitro studies documenting cocaine-induced vascular toxicity. PubMed and Academic Search Complete were used with relevant terms. Findings consist of the major mechanisms of cocaine-induced vasoconstriction, endothelial dysfunction, and accelerated atherosclerosis, emphasizing acute, chronic, and secondary effects of cocaine. The etiology underlying cocaine's acute and chronic vascular effects is multifactorial, spanning hypertension, impaired homeostasis and platelet function, thrombosis, thromboembolism, and alterations in blood flow. Early detection of vascular disease in cocaine addiction by multimodality imaging is discussed. Treatment may be similar to indications in patients with traditional risk-factors, with few exceptions such as enhanced supportive care and use of benzodiazepines and phentolamine for sedation, and avoiding β-blockers. Given the vascular toxicity cocaine induces, further compounded by smoking and alcohol comorbidity, and interacting with aging of the crack generation, there is a public health imperative to identify pre-symptomatic markers of vascular impairments in cocaine addiction and employ preventive treatment to reduce silent disease progression.

Long term effects of cocaine on the heart assessed by cardiovascular magnetic resonance at 3T

BACKGROUND

Cocaine is an addictive, sympathomimetic drug with potentially lethal effects. The prevalence and features of cocaine cardiotoxicity are not well known. We aimed to assess these effects using a comprehensive cardiovascular magnetic resonance (CMR) protocol in a large group of asymptomatic cocaine users.

METHODS

Consecutive (n = 94, 81 males, 36.6 ±7 years), non-selected, cocaine abusers were recruited and had a medical history, examination, ECG, blood test and CMR. The CMR study included measurement of left and right ventricular (LV, RV) dimensions and ejection fraction (EF), sequences for detection of myocardial oedema and late gadolinium enhancement (LGE). Images were compared to a cohort of healthy controls.

RESULTS

Years of regular cocaine use were 13.9 ± 9. When compared to the age-matched healthy cohort, the cocaine abusers had increased LV end-systolic volume, LV mass index and RV end-systolic volume, with decreased LVEF and RVEF. No subject had myocardial oedema, but 30% had myocardial LGE indicating myocardial damage.

CONCLUSIONS

CMR detected cardiovascular disease in 71% of this cohort of consecutive asymptomatic cocaine abusers and mean duration of abuse was related to probability of LV systolic dysfunction.

Regular cocaine use is associated with increased systolic blood pressure, aortic stiffness and left ventricular mass in young otherwise healthy individuals

BACKGROUND

The cardiovascular impact of cocaine use in otherwise healthy individuals who consider themselves 'social' users is not well established.

METHODS/RESULTS

Twenty regular cocaine users and 20 control subjects were recruited by word-of-mouth. Cardiovascular magnetic resonance was performed to assess cardiac and vascular structure and function. Cocaine users had higher systolic blood pressure compared to non-users (134±11 vs 126±11 mmHg, p = 0.036), a finding independent of age, body surface area, smoking and alcohol consumption. Cocaine use was associated with increased arterial stiffness - reflected by reduced aortic compliance (1.3±0.2 vs 1.7±0.5 cm2×10-2.mmHg-1, p = 0.004), decreased distensibility (3.8±0.9 vs 5.1±1.4 mmHg-1.10-3, p = 0.001), increased stiffness index (2.6±0.6 vs 2.1±0.6, p = 0.005), and higher pulse wave velocity (5.1±0.6 vs 4.4±0.6 m.s-1, p = 0.001). This change in aortic stiffness was independent of vessel wall thickness. Left ventricular mass was 18% higher in cocaine users (124±25 vs 105±16 g, p = 0.01), a finding that was independent of body surface area, and left atrial diameter was larger in the user group than controls (3.8±0.6 vs 3.5±0.3 cm, p = 0.04). The increased left ventricular mass, systolic blood pressure and vascular stiffness measures were all associated with duration and/or frequency of cocaine use. No late gadolinium enhancement or segmental wall motion abnormalities were seen in any of the subjects.

CONCLUSIONS

Compared with the non-user control cohort, cocaine users had increased aortic stiffness and systolic blood pressure, associated with greater left ventricular mass. These measures are all well known risk factors for premature cardiovascular events, highlighting the dangers of cocaine use, even in a 'social' setting, and have important public health implications.

Electrocardiographic findings associated with cocaine use in humans: a systematic review

Cocaine remains highly prevalent and accessible in the general population, continues to represent one of the most commonly reported substances in drug-related presentations to emergency departments, and is frequently implicated in drug-related deaths. Fatal cardiac arrhythmias are often suspected in the latter cases. In spite of this, its complex effects on the human cardiac conduction system remain poorly elucidated. In this article we sought to systematically review the medical literature to identify the electrocardiographic findings that have been linked to cocaine use in humans in an effort to highlight what physicians can expect to encounter when managing patients using the drug. The evidence is discussed, common findings are emphasized and clinical recommendations are proposed.

Smoking prevalence in addiction treatment: a review

INTRODUCTION

This review explores whether smoking prevalence in addiction treatment samples exceeds that shown in epidemiological data for persons with alcohol or other drug use disorders and whether smoking may have decreased over time in the addiction treatment population as it has done in the general population.

METHODS

English language papers published between 1987 and 2009 were searched electronically. Forty papers reporting smoking prevalence for addiction treatment samples in the United States were identified, and key predictor variables were abstracted. Random logistic models were used to assess relationships between each individual predictor (year, treatment modality, primary drug treated, government status, and public/private funding status) and smoking prevalence.

RESULTS

The lowest smoking prevalence aggregated for studies reported in any single year was 65%, well above epidemiological estimates reported among those with alcohol use and drug use disorders. The odds of smoking were higher in methadone maintenance programs (odds ratio [OR] = 2.25, CI = 1.08, 4.68) as compared with outpatient programs. No other variables in the model were significant. Reanalysis omitting recent studies that may represent outliers or confounding with type of treatment showed a small but significant decrease in smoking over time (OR = 0.9891, CI = 0.9888, 0.9893).

CONCLUSIONS

The very high smoking rates reported in addiction treatment samples warrant significant, organized, and systemic response from addiction treatment systems, from agencies that fund and regulate those systems, and from agencies concerned with tobacco control.

Combined pathological effects of cocaine abuse and HIV infection on the cardiovascular system: an autopsy study of 187 cases from the Fulton County Medical Examiner's office

This autopsy study evaluates the possible cumulative effects of cocaine use in HIV-infected adult individuals on cardiovascular tissue. A total of 187 autopsy case reports and available H&E sections of myocardium and coronary arteries were reviewed. Four major study groups were defined: (A) a total of 63 cases positive for cocaine and negative for HIV (COC); (B) 40 cases positive for HIV/AIDS and negative for cocaine (HIV), (C) 23 cases both HIV/AIDS and cocaine (HIV/COC), and (D) a control group of 61 age-, sex- and race-matched, negative for cocaine and for HIV (CONT). The following morphologic and demographic data were analyzed: heart weight, left ventricular hypertrophy, myocardial fibrosis, thickening of the intramyocardial vessels, myocarditis, acute or remote myocardial infarcts (MI), age, sex, and race. Increased frequency of coronary wall and adventitial infiltrates, myocarditis, and thickened intramyocardial vessels present in HIV/COC group (14.5%, 17.4%, and 17.4% vs. 6.5%, 3.3%, and 0% in CONT group) may indicate possible combined and/or cumulative effects of HIV and cocaine on cardiovascular pathology.

Illicit stimulant use in a United States heart failure population presenting to the emergency department (from the Acute Decompensated Heart Failure National Registry Emergency Module)

Illicit stimulant drug use may have a profound clinical impact in acute decompensated heart failure (ADHF). The chronic use of cocaine and methamphetamine may lead to overt cardiomyopathy and ADHF. The Acute Decompensated Heart Failure National Registry Emergency Module (ADHERE-EM) collected data on patients presenting to emergency departments with ADHF at 83 geographically dispersed hospitals in the United States. This registry was queried to determine the rate of self-reported illicit drug use in emergency department patients presenting with ADHF and compare these patients with those without illicit drug use. The registry enrolled 11,258 patients with ADHF with drug use data from January 2004 to March 2006. Of these patients, 594 (5.3%) self-reported current or past stimulant drug use. Compared with nonusers, these patients were more likely to be younger (median age 49.7 vs 76.1 years), to be African American (odds ratio 11.9, 95% confidence interval 9.8 to 14.4), and to have left ventricular ejection fractions <40% (odds ratio 3.4, 95% confidence interval 2.8 to 4.2). Admitted users had no difference in mortality (adjusted odds ratio 0.83, 95% confidence interval 0.25 to 2.72) compared with nonusers. In conclusion, data from ADHERE-EM suggest that a clinically important percentage of patients with ADHF report the use of illicit stimulant drugs. Although these patients are younger with a greater degree of LV dysfunction, they did not have greater risk-adjusted mortality.

Cardiovascular complications of cocaine: imaging findings

Cocaine is the second most commonly abused illicit drug in the US and the most common one involved in emergency department visits, the majority of which are related to the cardiovascular system. Cardiovascular complications related with cocaine abuse include myocardial ischemia and infarction, myocarditis, hypertrophic cardiomyopathy, dilated cardiomyopathy, aortic dissection, thrombosis, stroke and cerebral hemorrhage, and different forms of visceral ischemia, among others. In an era where cocaine use has reached epidemic proportions, it is necessary for the radiologist to understand the pathophysiology, clinical presentation, and imaging characteristics of its cardiovascular complications.

Cocaine and thrombosis: a narrative systematic review of clinical and in-vivo studies

Purpose

To systematically review the literature pertaining to the link between cocaine and either arterial or venous thrombosis.

Procedures

Narrative systematic review of Medline, CINAHL, Embase, Psycinfo and Cochrane databases supplemented by hand trawling of relevant journals and reference lists up to April 2007. In-vivo studies and those with clinical endpoints were included in the review.

Results

A total of 2458 abstracts led to 186 full-text papers being retrieved. 15 met the criteria for inclusion in the review. The weight of evidence would support cocaine as a pro-thrombotic agent. There is evidence of it activating thrombotic pathways. The effect of cocaine upon clinical endpoints has not been quantified though there is evidence of an association between cocaine and myocardial infarction particularly amongst young adults. Cocaine may also be a causal agent in cerebrovascular accident though studies lacked sufficient power to determine a statistically significant effect. There is a gap in the evidence pertaining to the issue of cocaine and venous thrombosis.

Conclusion

Clinicians should consider questioning for cocaine use particularly amongst young adults who present with cardiac symptoms. More epidemiological work is required to quantify the effect of cocaine upon both arterial and venous clotting mechanisms.

Cocaine activates calcium/calmodulin kinase II and causes cardiomyocyte hypertrophy

Cardiac hypertrophy occurs in as many as 47% of normotensive individuals who chronically use cocaine. We investigated the effects of cocaine, in concentrations commonly found in chronic cocaine users, on calcium/calmodulin kinase (CaMK), and whether cocaine can activate CaMK, increase cardiac myocyte protein expression, and cause cardiac hypertrophy in this manner. In series I to III, 0 (control) or cocaine in concentrations of 10 to 10 mol/L was added to cultured adult rat cardiac ventricular myocytes to determine by Western blots and by P incorporation the optimal treatment time and the optimal dose for CaMK activation. In series I, cocaine, 10 mol/L, increased myocyte CaMKII translocation from myocyte soluble to particulate fractions by > or =73 +/- 9% (P < 0.01) in comparison with controls but did not cause the translocation of CaMKI or CaMKIV. In series II and III, cocaine treatment of myocytes for 15 minutes increased maximal CaMKII activity by 86.5 +/- 13.3% (P < 0.001) and a cocaine dose of 5 x 10 mol/L increased CaMKII activity by 169.5 +/- 18.1% (P < 0.001). In series IV we measured by silver staining beta-myosin heavy chain protein (beta-MHC) expression in myocytes before and after cocaine and also CaMK inhibition with KN-62 (1-[N,O-bis-(5-isoquinolinesulfonyl)-N-methyl-L-tyrosyl]-4-phenylpiperazine). In these experiments, cocaine, 5x10 mol/L, increased myocyte protein concentration by 29.2 +/- 2.8%, and beta-MHC by 93.2 +/- 8.8% (P < 0.001). In series V and VI, cocaine effects on calcium currents (ICa) and intracellular Ca ([Ca]i) were determined before and after CaMK inhibition with KN-62 in rat myocytes. Cocaine, 10 mol/L, enhanced ICa peak amplitude in a voltage-dependent manner (by 173.9 +/- 14.9% at -20 mV and by 38.4 +/- 6.9% at 0 mV P < 0.01). Cocaine, 10 to 10 mol/L, in series VI promoted Ca transients from myocyte sarcoplasmic reticulum and increased [Ca]i to 607 +/- 141 x 10 mol/L (P < 0.05). KN-62 decreased cocaine-induced myocyte protein expression by 76.6%, and beta-MHC by 66.2% (P < 0.01) and significantly decreased cocaine-induced Ca transients and [Ca]i. We conclude that CaMKII activation is an important mechanism whereby cocaine can cause myocyte hypertrophy.

Cocaine cardiovascular toxicity

Cocaine abuse kills thousands every year. Preexisting coronary artery disease appears to account for many of the deaths, but often the mechanism is much more complex. There exists a widely held but utterly mistaken notion that cocaine-related deaths are due to drug overdose. Except in the case of drug couriers ("body packers") with massive drug exposure, death is not dose related, and cocaine blood levels cannot be used to predict toxicity. Most deaths occur after prolonged drug use, which initiates a series of changes at the molecular, cellular, and tissue levels. All of these changes favor sudden death. Potentially lethal myocardial alterations include hypertrophy, fibrosis, and microangiopathy. Recently it has become clear that genetic causes, such as fully or partially expressed congenital long QT syndrome, may also play a role. The relative importance of each of these factors is reviewed.

Cocaine and cardiovascular toxicity

Over the past 10 years a great deal has been learned about the cardiovascular effects of cocaine. In particular, the acute effects of cocaine have been studied extensively. Upon acute administration cocaine increases blood pressure and heart rate, primarily through an action on the sympathetic nervous system. Cocaine also suppresses the baroreflex response and vagal tone, further contributing to its effects on heart rate. At the same time cocaine is increasing the work-load on the heart it induces coronary artery vasoconstriction, potentially leading to cardiac ischemia. At higher doses cocaine can depress ventricular function and slow electrical conduction in the heart. Both these effects appear to be mediated by cocaine's local anesthetic action. The effects of cocaine mediated by the sympathetic nervous system are greatly reduced in anesthetized animals. Further, when cocaine is administered repeatedly over a short period of time, acute tolerance can develop to the sympathomimetic effects of cocaine. In contrast, the effects of cocaine mediated by its local anesthetic action do not appear blunted by anesthesia or susceptible to acute tolerance. With chronic administration, higher doses appear to induce tolerance while lower doses may induce sensitization to cocaine's sympathomimetic effects. Cocaine also induces a variety of pathological changes in the heart, including myocardial contraction band necrosis and ventricular hypertrophy. These effects of cocaine on the heart can all contribute to potentially lethal cardiovascular events. In addition to the effects of cocaine alone, the metabolites of cocaine may also contribute to cocaine's cardiovascular toxicity, and both licit and illicit drugs used in combination with cocaine might potentially alter its cardiovascular effects.

[Acute myocardial dysfunction after nasal infiltration with cocaine]

We report the case of a patient with severe myocardial dysfunction after nasal infiltration of cocaine during septoplasty. Complete recovery of myocardial function was observed in twelve days. Several reports have described chronic cardiomyopathy in long-term cocaine users, but only one case of acute cardiomyopathy. None of these cases were related to the medical use of cocaine.

Cocaine produces cardiac hypertrophy by protein kinase C dependent mechanisms

BACKGROUND

Chronic cocaine users can have as much as a 69% increase in left ventricular muscle mass without associated increases in arterial blood pressure, heart rate, renin, aldosterone, or cortisol. We determined whether cocaine directly increases cardiomyocyte protein content and whether protein kinase C is important in this process.

METHODS AND RESULTS

Adult rat cardiomyocytes were isolated and grown in cultures. In Series I experiments, cocaine, 10(-8) to 10(-6) M, or vehicle, in the absence or presence of phentolamine or metoprolol, was added to each culture and the cells were subsequently harvested. In Series II, cocaine, 10(-6) M, cocaine, 10(-6) M, plus bisindolylmaleimide, 10(-6) M, a protein kinase C inhibitor, or vehicle were added to each culture and the cells subsequently harvested. We determined the total protein content, the content of alpha-myosin and fetal beta-myosin heavy-chain protein, and the presence of protein kinase C isoforms in the cardiomyocyte soluble and particulate fractions. Protein kinase C translocation from the soluble to particulate fraction is indicative of activation. In Series III, we determined the cocaine effects on ERK, SAPK/JNK, and p38. In Series I, cocaine, 10(-8) to 10(-6) M, dose-dependently increased myocyte protein content by as much as 28%+/-2% (P<.001) and fetal beta-myosin heavy-chain protein content by 80%+/-2% (P<.001). Neither phentolamine nor metoprolol inhibited this process. In Series II, we determined that ventricular myocytes contain alpha (alpha), beta (beta), delta (delta), epsilon (epsilon), and zeta (zeta) protein kinase C isoforms. Cocaine, 10(-6) M, caused a 45+/-5% increase (P<.001) in protein kinase Calpha in the particulate fraction. The addition of a protein kinase C inhibitor to the myocyte cultures prevented the cocaine-induced translocation of protein kinase Calpha and limited the increase in beta-myosin heavy-chain protein content by >75% (P<.001). However, cocaine did not increase the phosphorylation of ERK, SAPK/JNK or p38 in Series III.

CONCLUSIONS

Cocaine increases adult cardiomyocyte protein content by protein kinase Calpha-dependent mechanisms, and this process can contribute to the cardiac hypertrophy and cardiomyopathy that results from chronic cocaine use.

The pathophysiology of cocaine abuse

Cocaine is a naturally occurring alkaloid that increases dopamine concentrations in the reward centers of the brain. There has been a marked increase in cocaine abuse over the last two decades. A neuropsychological stimulant, cocaine also reduces somnolence, increases alertness and improves concentration. However, cocaine abuse has many pathophysiological consequences. These fall broadly into four groups: pathology associated with a drug abusing lifestyle, pathology that occurs whilst intoxicated with (but not directly due to) the drug, pathology associated with drug administration and pathology resulting from pharmacological action of the drug. This review provides a detailed description of the physiological, pharmacological, and pathological effects of cocaine, and highlights the forensic and medicolegal implications of cocaine abuse.

Cardiovascular disorders associated with cocaine use: myths and truths

Cocaine produces a pattern of cardiovascular responses that are associated with apparent myocardial ischemia, arrhythmias, and other life-threatening complications in some individuals. Despite recent efforts to better understand the causes of cocaine-induced cardiovascular dysfunction, there remain a number of unanswered questions regarding the specific mechanisms by which cocaine elicits hemodynamic responses. This review will describe the actions of cocaine on the cardiovascular system and the evidence for the mechanisms by which cocaine elicits hemodynamic and pathologic responses in humans and animals. The emphasis will be on experimental data that provide the basis for our understanding of the mechanisms of cardiovascular toxicity associated with cocaine. More importantly, this review will identify several controversies regarding the causes of cocaine-induced cardiovascular toxicity that as yet are still debated. The evidence supporting these findings will be described. Finally, this review will outline the obvious deficits in our current concepts regarding the cardiovascular actions of cocaine in hope of encouraging additional studies on this grave problem in our society.

Effects of cocaine on the coronary arteries

BACKGROUND

A number of studies have documented myocardial ischemia and infarction associated with cocaine use. Mismatch between myocardial oxygen supply and demand from cocaine-induced vasoconstriction and increased myocardial workload are often invoked as the major postulated mechanism by which cocaine induces myocardial ischemia. This article reviews the literature studying the effects produced by cocaine on the coronary arteries to provide insight into the various pathophysiologic mechanisms by which cocaine triggers acute cardiac ischemia or infarction.

METHODS

We reviewed the published literature describing the effects of cocaine on the coronary arteries. A MEDLINE search of English language articles published between 1985 and 2000 was performed. Key words included coronary arteries, coronary vasoconstriction, vasospasm, coronary vasodilation, cardiac vasculature, myocardial ischemia, platelets, thrombosis, and cocaine. Both animal and human studies were included. The bibliographies of identified articles were also explored for additional sources of information.

RESULTS

A recreational dose of cocaine increases the heart rate by approximately 30 beats/min. It also increases the blood pressure by 20/10 mm Hg. These increases are modest, are equivalent to mild exercise, and are not believed to be sufficient to result in myocardial ischemia in the majority of cases. Animal and human studies have documented cocaine-induced early coronary artery vasodilation as shown by a decrease in coronary perfusion pressure ranging from 13% to 68%. This was followed by a more sustained vasoconstriction demonstrated by a decrease in epicardial coronary artery diameter ranging from 5% to 30% with various doses of cocaine by various methods of administration. These changes alone are also an unlikely explanation for cocaine-induced myocardial ischemia. Therefore neither increases in myocardial workload nor hemodynamic changes are sufficient to explain cocaine-induced myocardial ischemia. However, evidence also exists that cocaine activates platelets and promotes thrombosis, resulting in intracoronary thrombus formation. Cocaine may also promote premature and more severe coronary atherosclerosis.

CONCLUSION

The etiology of cocaine-induced myocardial ischemia is complex and is likely to be multifactorial. It appears to be the result of coronary artery vasoconstriction, intracoronary thrombosis, and accelerated atherosclerosis.

Drug use and barriers to use of health care services

This paper examines barriers to health care utilization and the correlates associated with these barriers. As part of a larger study of health services utilization, the study sample of 1085 including injection drug users, other chronic users of heroin or cocaine, and a demographically similar group who had used neither heroin nor cocaine, was selected based on the criterion of not having received health care for at least one health problem within the previous 12 months. Both categories of chronic drug users were more likely than non-users not to want health care treatment and to put off seeking needed health care.

Cocaine increases beta-myosin heavy-chain protein expression in cardiac myocytes

BACKGROUND

As many as 47% of chronic cocaine users develop cardiac ventricular hypertrophy. The presence and degree of cocaine-induced ventricular hypertrophy is not correlated with the use of other substances of abuse such as alcohol or cigarettes. Moreover, this hypertrophy occurs in individuals without sustained increases in arterial blood pressure or heart rate, or increases in the plasma concentration of renin, aldosterone, norepinephrine, or cortisol. Therefore, we investigated whether cocaine, in concentrations commonly found in cocaine users, has any direct effects on the protein content in cardiac ventricular myocytes. We compared the effects of cocaine with norepinephrine, which increases the total protein content, especially beta-myosin heavy-chain contractile protein (beta-MHC), in cardiac ventricular myocytes.

METHODS

Experiments were performed on 30-day-old rat ventricular myocytes suspended in culture media and cultured in flasks. In 12 suspension-culture experiments, cocaine or norepinephrine, in doses of 0 (control) or 10(-6) mol/L was added to each culture and the cells were harvested on day 5. In 16 flask-culture experiments, cocaine or norepinephrine was added to each culture on day 7 in doses of 0 (control-vehicle), 10(-7), or 10(-6) mol/L and the cells were harvested on day 10. The total protein content and the myosin protein expression of the myocytes in each culture were determined. Juvenile and adult rat cardiac myosin protein is predominately alpha-myosin heavy-chain protein (alpha-MHC), whereas beta-MHC occurs primarily in fetal rat hearts.

RESULTS

In the suspension-culture experiments, cocaine, 10(-6) mol/L, increased the cardiomyocyte total protein concentration by 29% +/- 2% (P <.001) and the beta-MHC expression by 81% +/- 10% (P <.01) in comparison with the control myocytes. Cocaine slightly decreased cardiomyocyte alpha-MHC. Norepinephrine increased the total protein concentration by 21% +/- 3% (P <.001) and the beta-MHC expression by 59% +/- 10% (P <.01), but did not increase alpha-MHC expression. In the flask-culture experiments, cocaine, 10(-6) mol/L, maximally increased the total protein concentration by 28% (P <.001), the protein/cell ratio by 57% +/- 10% (P <.01), and the beta-MHC expression by 85% +/- 8% (P <.01). Cocaine slightly decreased alpha-MHC. Norepinephrine, 10(-6) mol/L, maximally increased the total protein concentration by 35%, the protein/cell ratio by 63% +/- 9% (P <.01), and the expression of beta-MHC by 78% +/- 11% (P <. 01). Norepinephrine did not increase alpha-MHC expression. In 18 separate flask-culture experiments, cocaine, 10(-6) mol/L, was added to the cardiomyocyte cultures after the addition of phentolamine (n = 9), in concentrations of 10(-7) to 10(-5) mol/L, or metoprolol (n = 9), in concentrations of 10(-7) to 10(-5) mol/L. Neither phentolamine nor metoprolol inhibited the cocaine-induced increase in cardiomyocyte total protein content or the expression of beta-MHC.

CONCLUSION

Cocaine, similar to norepinephrine, significantly increases the total protein content and the expression of beta-MHC in cardiac ventricular myocytes. In this manner, cocaine may cause cardiac ventricular hypertrophy. This process is not inhibited by alpha- or beta-adrenergic receptor blockade.

Brugada-type electrocardiographic pattern induced by cocaine

Right bundle branch block with coved ST-segment elevation in leads V1 through V3 is the electrocardiographic (ECG) marker of the Brugada syndrome. We describe a healthy young man with a normal baseline ECG in whom a transient Brugada pattern was observed repeatedly after recreational cocaine use. Intravenous administration of procainamide and subsequent intravenous propranolol followed by noradrenaline failed to reproduce the Brugada sign. An electrophysiologic study performed in the presence of the Brugada ECG pattern showed no inducible arrhythmias. This case illustrates that, in susceptible individuals, cocaine may provoke the Brugada sign. The clinical importance of this cocaine-induced ECG abnormality is currently unknown.

Coronary vascular responses to short-term cocaine administration in conscious baboons compared with dogs

OBJECTIVES

Cardiovascular complications of cocaine use represent an important clinical problem, yet the mechanisms by which cocaine predisposes to myocardial ischemia are poorly understood.

BACKGROUND

The effects of cocaine on the coronary circulation have been studied extensively in experimental animal models, but have failed to recapitulate the clinical findings reported in humans who use cocaine.

METHODS

We studied 12 conscious, chronically instrumented dogs and 5 conscious, chronically instrumented baboons to determine whether there were important species differences in the response to cocaine.

RESULTS

Comparable doses of intravenous cocaine caused similar increases in left ventricular systolic, diastolic and mean arterial pressure in the two species. However, the peak coronary blood flow response in baboons (+8 +/- 3 from 47 +/- 6 ml/min) was less compared with dogs (+15 +/- 4 from 41 +/- 4 ml/min), while the coronary vascular resistance response was greater in baboons (+0.60 +/- 0.09 from 1.94 +/- 0.09 mm Hg/ml/mm) compared with dogs (+0.35 +/- 0.09 from 2.24 +/- 0.10 mm Hg/ml/min). Although myocardial oxygen consumption responses were similar between species, there was a significant difference (p < 0.05) in oxygen delivery between baboons (+164 +/- 47 from 705 +/- 59 ml of oxygen per minute) and dogs (+397 +/-51 from 656 +/- 33 ml of oxygen per minute) that was attributable to a significant (p < 0.05) increase in hemoglobin concentration in dogs (+2.1 +/- 0.5 g/dl) that was not observed in baboons. Consequently, cocaine caused a significant increase in myocardial oxygen extraction and decreased coronary sinus pH in baboons, but not dogs.

CONCLUSIONS

Cocaine caused greater coronary vasoconstriction and greater requirements for oxygen extraction in baboons compared with dogs.

Heart and lung preservation for transplantation

Since the beginning of transplantation the search for optimal means of organ preservation has been ongoing. One of the major causes of death early following heart or lung transplantation is graft failure. Factors that play a role in this problem include recipient and donor issues, but clearly procurement techniques and preservation solutions are important. This article summarizes the history, current clinical practice, and research devoted to heart and lung preservation for transplantation.

Cardiovascular effects of acute and chronic cocaine administration in pregnant and nonpregnant rabbits

The effects of cocaine administration on cardiovascular parameters were studied in anesthetized nonpregnant and pregnant rabbits with no prior exposure to cocaine and in pregnant rabbits repeatedly administered cocaine (4 mg/kg, bid, iv) for 15-20 days prior to the experiment. Rabbits were instrumented to determine the effects of cocaine on blood pressure, heart rate, and organ blood flows. Administration of the 1 and 2 mg/kg doses of cocaine increased blood pressure and decreased heart rate in both pregnant and nonpregnant rabbits. In contrast, the 4 mg/kg dose of cocaine caused reductions in both blood pressure and heart rate. Cocaine (1, 2, and 4 mg/kg, iv) also caused dose-dependent reductions in organ blood flows. Interestingly, cocaine did not affect uterine blood flow in the nonpregnant rabbits, whereas uterine and placental flows were markedly reduced in both groups of pregnant rabbits. Chronic treatment with cocaine caused a significant increase in the basal blood flow to the placenta and spleen, and a more precipitous decrease in blood flow in both organs in response to an acute injection of cocaine. The chronically treated rabbits also had a greater incidence of cardiac arrhythmias in response to an acute injection of cocaine (4 mg/kg, iv). Rabbits that received repeated administrations of cocaine experienced more prolonged reductions in blood flow than rabbits with no prior exposure to cocaine. These studies show that cocaine has marked effects on organ blood flows and that pregnancy and repeated prior administrations of cocaine can enhance these effects.

Cocaine: pathophysiology and clinical toxicology

PURPOSE

To review the medical complications of cocaine abuse and the mechanisms of action of cocaine that contribute to medical complications.

DATA SOURCES

Pertinent articles identified through a MEDLINE search of the English-language literature from 1985 to 1996 and through a manual search of bibliographies of all identified articles.

STUDY SELECTION

All articles describing complications of cocaine use including case reports, small reported series, and review articles.

DATA SYNTHESIS

A qualitative description of reported complications.

RESULTS

Since the introduction of freebase and crack cocaine, multiple medical complications have been observed, and all major body organ systems have been affected. Cocaine can cause acute strokes, myocardial infarction, cardiac dysrhythmias, pulmonary edema, rhabdomyolysis, and acute renal failure.

CONCLUSION

Adverse reactions to cocaine should be considered in the differential diagnosis of acute ischemic events that occur in young adults. General awareness of the significant complications of cocaine will facilitate early diagnosis and prompt treatment.

Estimating the dollar value of health outcomes from drug-abuse interventions

OBJECTIVES

People who abuse drugs suffer from a host of medical problems that impose costs on both the abusers and society as a whole. Drug-abuse treatment and other interventions can help alleviate these medical problems, leading to health status improvements for chronic drug users and reduced social costs. The authors' dual purpose here is to (1) propose a theoretically rigorous yet easy-to-apply methodology for estimating the health-related costs of drug abuse and (2) demonstrate the methodology by estimating the potential dollar value of avoiding adverse health consequences as a result of successful drug-abuse interventions.

METHODS

The authors' proposed multiattribute quality-adjusted life year methodology for estimating the value of avoiding morbidity and mortality involves eight steps to be followed sequentially. The framework is based on developing a common unit of well-being (i.e., quality-adjusted life year) that can be applied to all types of health conditions. If all health states can be denominated in this common unit, then the process of valuation is straightforward and consistent across all types of illnesses and diseases. The methodology is relatively inexpensive to execute because the estimation procedures are not complicated technically and the data demands are modest. Also, this approach incorporates elements from several disciplines, including psychology, epidemiology, medicine, and economics. Finally, the proposed methodology is flexible enough to cover a wide range of illnesses and diseases so that consistent and comparable estimates can be generated.

RESULTS

The authors estimate the dollar value of avoiding acute hepatitis B, human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS), hypertension, bacterial pneumonia, sexually transmitted diseases, and tuberculosis for a white male aged 32 years. The authors' results illustrate that estimated avoided morbidity values can vary significantly across the range of health consequences associated with drug abuse. At the upper end of the range, the value of avoiding only the morbidity associated with a single case of HIV/AIDS is approximately $157,811 for the period beginning with transmission of HIV, through late-stage HIV and AIDS, and ending just before death.

CONCLUSIONS

People who abuse drugs suffer from many medical problems in addition to their addiction. The proposed approach for estimating the dollar value of avoiding adverse health consequences provides policy analysts, evaluators, and researchers a method to calculate theoretically based benefit estimates for use in a benefit-cost analysis of drug-abuse interventions.

Mechanism of the systemic, left ventricular, and coronary vascular tolerance to a binge of cocaine in conscious dogs

BACKGROUND

Prior experimental studies have emphasized the cardiovascular effects of acute, single doses of cocaine. However, cardiovascular complications are most often reported in chronic users, who have been exposed to repetitive doses of cocaine. It remains unclear whether there is tolerance or sensitization to the systemic, left ventricular, and coronary hemodynamic effects of a binge of cocaine.

METHODS AND RESULTS

We studied 11 conscious, chronically instrumented dogs to determine the systemic pressor, inotropic, chronotropic, and coronary vascular resistance responses to cocaine (1 mg/kg IV) administered every 25 minutes for five doses. There was progressive tolerance to the systemic pressor (mean arterial pressure: first dose, +42 +/- 4% from 97 +/- 2 mm Hg; fifth dose, +8 +/- 3% from 116 +/- 7 mm Hg; P < .01) and heart rate (first dose, +45 +/- 8% from 93 +/- 5 bpm; fifth dose, +8 +/- 2% from 109 +/- 9 bpm; P < .01) responses and abolition of the positive inotropic (left ventricular dP/dt: first dose, +19 +/- 4% from 2824 +/- 75 mm Hg/s; fifth dose, -3 +/- 5% from 2531 +/- 436 mm Hg/s; P < .01) and coronary vasoconstrictor (coronary vascular resistance: first dose, +38 +/- 9% from 1.9 mm Hg.mL-1.min-1; fifth dose, -7 +/- 2% from 2.6 +/- 0.2 mm Hg. mL-1.min-1; P < .01) responses to a binge of cocaine despite progressive increases in peak plasma cocaine concentrations. In contrast, both the plasma norepinephrine and epinephrine responses were attenuated with repetitive exposure to cocaine, whereas myocardial alpha and beta-adrenergic responsiveness was maintained.

CONCLUSIONS

Repetitive cocaine administration is associated with the development of early and progressive tolerance to systemic, left ventricular, and coronary vascular effects of cocaine. The mechanism of the tolerance involves neither impaired myocardial nor coronary vascular responsiveness to adrenergic stimulation but, rather, attenuated catecholamine responses to repetitive cocaine administration.

The recreational drug user in the intensive care unit: a review

This paper describes the mode of action of a set of recreational drugs that may cause patients problems that are severe enough to warrant admission to an intensive care unit. The mechanism of harm will be examined as well as some of the strategies used to deal with these problems. A general view of the chosen group will be outlined, followed by a breakdown of the drugs into specific categories, with review of the harmful effects of individual drugs. It is the intention of the authors to review depressant drugs at a later stage.

Cardiovascular hypertrophy and increased vascular contractile responsiveness following repeated cocaine administration in rabbits

The effects of repeated cocaine administration on contractile responses were studied in adult rabbits. Repeated cocaine exposure caused a significant increase in the maximal response of the aorta to the agonists norepinephrine and serotonin as well as the receptor- independent stimulus KCl when compared to the saline controls. Cocaine exposure caused a significant increase in the wet weights of both heart and aorta. When the contraction was normalized to the wet weight of the aorta there was no difference between rabbits administered cocaine and saline. Acute cocaine administration caused a time-dependent increase in immunoreactivity of the proto-oncogene c-Fos in the aorta. These results show that repeated cocaine administration leads to the development of cardiovascular hypertrophy.

Racial differences in the prevalence of left ventricular hypertrophy among chronic cocaine abusers

There are racial differences in the prevalence and pattern of left ventricular (LV) hypertrophy in hypertension. This study was performed to determine whether racial differences also exist in LV hypertrophy among chronic cocaine users. We studied 112 chronic cocaine abusers < 45 years old in whom normal blood pressures (< or = 140/90 mm Hg) were recorded 3 times daily for 3 weeks. LV wall thickness and mass were measured echocardiographically. Technically adequate studies were obtained in 79 blacks and 33 whites. Self-reported cocaine use was higher in whites than in blacks (688 +/- 516 vs 431 +/- 468 $/week, p = 0.03). There were no group differences in terms of duration of cocaine use, age, height, weight, blood pressure, LV dimensions, or left atrial size. However, posterior wall thickness (1.13 +/- 0.17 vs 1.03 +/- 0.14 cm, p = 0.0035) and LV mass index (113 +/- 25 vs 94 +/- 19 g/m2, p = 0.0001) were significantly greater in blacks. LV hypertrophy, defined as an M-mode LV mass index > or = 134 g/m2, was present in 24 blacks (30%) and 2 whites (6%) (p = 0.011). When defined as a posterior wall thickness > or = 1.2 cm and a 2-dimensional echocardiographic LV mass index > or = 105 g/m2, LV hypertrophy was present in 37 of 79 blacks (47%) and in 6 of 33 whites (18%) (p = 0.0086). Cocaine-related LV hypertrophy is more prevalent in black men than in white men.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of blood doping in the coronary vasoconstrictor response to cocaine

BACKGROUND

The mechanism by which cocaine induces myocardial ischemia remains controversial. Most prior studies have postulated that cocaine-induced coronary vasoconstriction limits myocardial oxygen delivery during times of increased myocardial oxygen demand.

METHODS AND RESULTS

To determine the contribution of altered myocardial metabolic demands to the coronary vasoconstrictor effects of intravenous cocaine (COC 1 mg/kg), we studied 13 conscious, chronically instrumented dogs in the intact state and with heart rate held constant with atrial pacing in the presence and absence of beta-adrenergic blockade with propranolol (2 mg/kg) to limit the inotropic and chronotropic effects of cocaine on associated increases in myocardial oxygen consumption. In the intact state, COC caused a prompt increase in coronary blood flow (+30 +/- 3%, P < .01) that returned rapidly to baseline within 10 minutes, whereas coronary vascular resistance did not increase significantly (+17 +/- 6%, P < .05) until 15 minutes after COC. Notably, myocardial oxygen consumption increased (+57 +/- 4%, P < .01) to a greater extent than oxygen delivery (+42 +/- 3%, P < .01) during the first 2.5 minutes, requiring increased oxygen extraction (from 75 +/- 1% to 80 +/- 1%, P < .01), although only transiently. Thereafter, enhanced oxygen delivery matched the required oxygen consumption without further need to extract additional oxygen. Surprisingly, the enhanced oxygen delivery associated with COC in conscious dogs did not depend on persistent increases in coronary blood flow but rather was due to enhanced arterial oxygen content (+22 +/- 4%, P < .01) as a result of a significant "blood doping" effect with associated increases in circulating hemoglobin from 12.1 +/- 0.4 to 14.2 +/- 0.6 g/dL (P < .01), which persisted for 60 minutes.

CONCLUSIONS

The myocardial oxygen requirements associated with COC administration have a significant impact on both the magnitude and the mechanism of the coronary vasoconstrictor effects of COC in conscious dogs. Furthermore, the enhanced myocardial oxygen delivery associated with COC administration is not dependent solely on coronary blood flow responses but is due to a significant "blood doping" effect associated with COC.

Left ventricular morphologic features and function in nonhospitalized cocaine users: a quantitative two-dimensional echocardiographic study

To determine whether left ventricular (LV) hypertrophy or dysfunction is present in nonhospitalized cocaine users, we performed quantitative two-dimensional echocardiography in 20 intravenous cocaine users and 20 age- and sex-matched controls. Cocaine users were normotensive, had begun taking cocaine an average of 14 years earlier, and had used cocaine an average of 8 times/mo during the preceding year. There were no significant differences between cocaine users and control subjects for LV mass index (79 vs 74 gm/m2, respectively), mean wall thickness (0.95 vs 0.91 cm), end-diastolic volume index (55 vs 56 ml/m2), end-systolic volume index (17 vs 19 ml/m2), or ejection fraction (70 vs 66%; p > or = 0.09 for all comparisons). Moreover, none of the cocaine users or control subjects had significant regional wall motion abnormalities, and none of the subjects or controls had ejection fractions < 55%. Thus we found little evidence that significant LV hypertrophy or dysfunction is present in nonhospitalized cocaine users. From these results we speculate that cocaine-associated LV hypertrophy and dysfunction may be restricted to certain high-risk groups of chronic cocaine users.

Lack of association of recreational cocaine and alcohol use with left ventricular mass in young adults. The Coronary Artery Risk Development in Young Adults (CARDIA) study

OBJECTIVES

This study examined the associations of left ventricular mass with self-reported cocaine and alcohol use prevalent in the young adult population.

BACKGROUND

Increased left ventricular mass has been associated with long-term use of cocaine and alcohol; however, few of the published studies have been population based.

METHODS

Data from 3,446 black and white participants (mean age 29.9 years) in the Coronary Artery Risk Development in Young Adults (CARDIA) study were used to examine the associations between echocardiographically measured left ventricular mass obtained from 1990 to 1991 and self-reported cocaine and alcohol use. Categories of cocaine use were those who denied ever using cocaine (n = 2,122), experimental users who admitted to cocaine use only 1 to 10 times in their lifetime (n = 755) and recurrent users who admitted to cocaine use > 10 times in their lifetime (n = 568). For alcohol consumption, categories were abstainers who consistently denied any alcohol consumption in the year before each of the three CARDIA examinations (n = 275), occasional users who admitted consuming alcohol less than once a week or not at all during the year before the third examination (n = 1,322), moderate users who consumed 1 to 209 ml of alcohol/week during the year before the third examination (n = 1,524) and heavy users who consumed > or = 210 ml of alcohol/week during the year before the third examination (n = 323). Estimated power to detect a 10% difference in left ventricular mass between groups was > 80%.

RESULTS

For white women, left ventricular mass was significantly higher among those who reported 1 to 10 lifetime uses of cocaine than in never-users (128.5 g [SE 2.0] vs. 122.7 g [SE 1.4], p = 0.002). There were no other significant differences in left ventricular mass among categories of cocaine or alcohol use in unadjusted analyses or among analyses controlling for age, body mass index, alcohol or cocaine use, physical activity, cigarette smoking status and systolic blood pressure.

CONCLUSIONS

At the levels of consumption reported, neither cocaine nor alcohol use was associated with left ventricular mass in this cohort of healthy young adults.

Cardiac complications of cocaine abuse

Cardiac complications of cocaine abuse and a rational approach to evaluating and managing them are described. Cardiac abnormalities reported among asymptomatic cocaine abusers include echocardiographic left ventricular hypertrophy and segmental wall motion abnormalities. Electrocardiogram may reveal increased QRS voltage, ST-T changes, and pathologic Q waves. Episodes of ST elevation may be seen during Holter monitoring. The management of cocaine-abusing patients who present to an emergency room with acute chest pain is controversial because the two reported studies yielded conflicting results regarding the incidence of myocardial infarction (MI). Even in the absence of infarction, electrocardiographic abnormalities are common among these patients, which complicates the decision-making regarding hospitalization. Pathophysiology of cocaine-related MI is discussed. Distinct clinical features of cocaine-related MI make it clear that the association between the two is not just temporal. However, considering the number of persons abusing cocaine, it is a rarity. Beta-adrenergic blockers should be avoided in the treatment of cocaine-induced myocardial ischemia which is best treated with nitrates and calcium-channel blockers. Reports of cocaine-induced myocarditis and cardiomyopathy are reviewed. Experimental studies and clinical case reports suggest that cocaine may cause lethal arrhythmias. Cocaine prolongs repolarization by a depressant effect on potassium current and may generate early afterdepolarizations. It is possible that cocaine-associated arrhythmias are secondary to vasospasm-related ischemia and reperfusion as well.

Cocaine: a review of its toxic actions on cardiac function

It has become increasingly apparent that cocaine abuse can provoke lethal cardiac events, including myocardial infarction and ventricular fibrillation. The mechanisms responsible for these cardiotoxic actions of cocaine largely remain to be determined. Cocaine has two primary pharmacological properties that can adversely affect the heart and vasculature. Cocaine acts both as a local anesthetic (sodium and potassium channel blockade) and as a powerful cardiac stimulant that accentuates the actions of the sympathetic nervous system (inhibition of central and peripheral neuronal catecholamine uptake). The local anesthetic properties could impair impulse conduction, as well as elicit inhomogeneities in repolarization (refractory period), which creates an ideal substrate for reentrant arrhythmias. In addition, high doses of cocaine can depress contractile function due to inhibition of sodium/calcium exchange that results from decreased sodium influx (local anesthetic action). These actions are particularly obvious when sympathomimetic effects of cocaine are blunted. In a similar manner, the cocaine-induced accumulation of catecholamines potentiates the activation of alpha- and beta-adrenergic receptors, which can provoke coronary vasospasm (myocardial ischemia and infarction), increased contractile force (increased metabolic demand), and cardiac arrhythmias. The activation of adrenergic receptors will elicit a cascade of second messengers, ultimately provoking an increase in cytosolic calcium. These elevations in cytosolic calcium can provoke oscillations in membrane potential, triggering sustained action potential generation and extrasystoles. In particular, activation of the alpha IA-adrenergic receptor subtype and corresponding increase in calcium influx via voltage sensitive (L type) channels may play a critical role in the genesis of malignant arrhythmias. Thus, the adrenergic and local anesthetic properties of cocaine could act synergistically to elicit toxic actions on the heart.

Frequency and type of electrocardiographic abnormalities in cocaine abusers (electrocardiogram in cocaine abuse)

Electrocardiographic abnormalities of 200 asymptomatic, chronic cocaine abusers (aged < or = 45 years, 69% black) admitted for rehabilitation (group 1) were compared with 38 cocaine abusers treated in the emergency room (group 2), 21 cocaine abusers who died suddenly (group 3), and 425 control subjects from the general population. In group 1, 39% of electrocardiograms were abnormal: Increased QRS voltage was noted in 27%, ST elevation in 22%, ST-T changes in 17%, and prior myocardial infarction in 3%. Increased QRS voltage (35% vs 10%, p = 0.00007) and ST elevation (26% vs 13%, p = 0.0278) were more prevalent in blacks than in whites. With use of Minnesota coding, electrocardiograms in group 1 were compared with those of 141 black and 284 white men (aged < 40 years) from the general population. ST elevation was more prevalent in both black (22% vs 8%, p = 0.00073) and white (15% vs 1%, p < 0.00001) cocaine abusers than in the general population. Compared with group 1, group 2 had higher prevalence of sinus tachycardia (16% vs 1%, p = 0.0002), supraventricular tachycardia (5% vs 0%, p = 0.024), ST-T changes (34% vs 17%, p = 0.0164), and QTc > 440 ms (26% vs 4%, p = 0.00003); mean QTc was also greater among group 2 subjects (427 +/- 38 vs 404 +/- 19 ms, p < 0.0001). In group 3, QTc was > 440 ms in 6 of 8 subjects (75%) with 12-lead electrocardiograms.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiovascular manifestations of cocaine abuse. A case of recurrent dilated cardiomyopathy

The medical complications of cocaine abuse are being encountered by clinicians with increasing frequency. The cardiovascular manifestations of cocaine abuse include chest pain, myocardial ischemia and infarction, congestive heart failure, arrhythmias, infective endocarditis, and aortic dissection. The pathogenesis of these cardiovascular complications has not been fully elucidated but may be related to a combination of the sympathomimetic and membrane anaesthetic effects of cocaine. We present these concepts in a case discussion format.