Myocardial infarction with normal coronary arteries: the pathologic and clinical perspectives

Diagnostic Angiograms and Percutaneous Coronary Interventions in Pregnancy

Cardiovascular disease is the leading indirect cause of maternal mortality in the UK. Pregnancy increases the risk of acute MI (AMI) by three- to fourfold secondary to the profound physiological changes that place an extra burden on the cardiovascular system. AMI is not always recognised in pregnancy and there is concern among both clinicians and patients regarding catheter-based interventions due to fears of foetal irradiation and risks to the foetus. This article evaluates the current state of knowledge on AMI in pregnancy with particular emphasis on pregnancy-associated spontaneous coronary artery dissection and percutaneous coronary intervention as the revascularisation procedure for AMI. Special considerations that must be made in patients requiring percutaneous coronary intervention for pregnancy-associated spontaneous coronary artery dissection and the current recommendations on arterial access, methods of minimising radiation and stent selection are discussed.

Ultrasound in cardiac trauma

In the perioperative period, the emergency department or the intensive care unit accurate assessment of variable chest pain requires meticulous knowledge, diagnostic skills, and suitable usage of various diagnostic modalities. In addition, in polytrauma patients, cardiac injury including aortic dissection, pulmonary embolism, acute myocardial infarction, and pericardial effusion should be immediately revealed and treated. In these patients, arrhythmias, mainly tachycardia, cardiac murmurs, or hypotension must alert physicians to suspect cardiovascular trauma, which would potentially be life threatening. Ultrasound of the heart using transthoracic and transesophageal echocardiography are valuable diagnostic tools that can be used interchangeably in conjunction with other modalities such as the electrocardiogram and computed tomography for the diagnosis of cardiovascular abnormalities in trauma patients. Although ultrasound of the heart is often underused in the setting of trauma, it does have the advantages of being easily accessible, noninvasive, and rapid bedside assessment tool. This review article aims to analyze the potential cardiac injuries in trauma patients, and to provide an elaborate description of the role of echocardiography for their accurate diagnosis.

Risk factors and in-hospital outcome of acute ST segment elevation myocardial infarction in young Bangladeshi adults

Background

South Asians have a higher overall incidence rate and younger age of onset for acute myocardial infarction (AMI) compared to Western populations. However, limited information is available on the association of preventable risk factors and outcomes of AMI among young individuals in Bangladesh. The aim of this study was to determine the risk factors and in-hospital outcome of AMI among young (age ≤40 years) adults in Bangladesh.

Methods

We conducted a prospective observational study among consecutive 50 patients aged ≤40 years and 50 patients aged >40 years with acute ST Segment Elevation Myocardial Infarction (STEMI) and followed-up in-hospital at the National Institute of Cardiovascular Diseases (NICVD). Clinical characteristics, biochemical findings, diet, echocardiography and in-hospital outcomes were compared between the two groups. Multivariate logistic regression was performed to assess the association between risk factors and in-hospital outcome in young patients adjusting for other confounding variables.

Results

The mean age of the young and older patient groups was 36.5 ± 4.6 years and 57.0 ± 9.1 years respectively. Male sex (OR 3.4, 95 % CI 1.2 − 9.75), smoking (OR 2.4, 95 % CI 1.04 − 5,62), family history of MI (OR 2.4, 95 % CI 1.11 − 5,54), homocysteine (OR 1.2, 95 % CI 1.08 − 1.36), eating rice ≥2 times daily (OR 3.5, 95 % CI 1.15 − 10.6) and eating beef (OR 4.5, 95 % CI 1.83 − 11.3) were significantly associated with the risk of AMI in the young group compared to older group. In multivariate analysis, older patients had significantly greater chance of developing heart failure (OR 7.5, 95 % CI 1.51 to 37.31), re-infarction (OR 7.0, 95 % CI 1.08 − 45.72), arrhythmia (OR 15.3, 95 % CI 2.69 − 87.77) and cardiogenic shock (OR 69.0, 95 % CI 5.81 − 85.52) than the younger group.

Conclusion

Younger AMI patients have a different risk profile and better in-hospital outcomes compared to the older patients. Control of preventable risk factors such as smoking, unhealthy diet, obesity and dyslipidemia should be reinforced at an early age in Bangladesh.

Acute coronary syndrome in two patients with mechanical valve prostheses

We report 2 similar cases of embolic myocardial infarction due to thrombus on a mechanical prosthesis despite anticoagulation therapy. In our first case, aspiration of the thrombus was performed successfully. Our second patient was given medical treatment with target international normalized ratio values between 3.5 and 4.0.

Cryptogenic left main thrombosis: successful mechanical clot retrieval with a self-expanding trapping device

We present the case of a 52-year-old male with ST-segment elevation myocardial infarction due to a spontaneous large left main thrombosis, without any angiographic evidence for coronary artery disease. After multiple unsuccessful attempts of thrombaspiration the large clot was mechanically retrieved by a flow restoration device that was primarily made for intracranial interventions. Intravascular ultrasound revealed marginal lumen narrowing after the intervention, but the final coronary angiogram showed a patent left main and there was no relevant stenosis remaining.

Coronary spasm and acute myocardial infarction due to a mutation (V734I) in the nucleotide binding domain 1 of ABCC9

BACKGROUND

Alterations in coronary vasomotor tone may participate in the pathogenesis of acute myocardial infarction (AMI). Vascular ATP-sensitive K(+) (KATP) channels, formed by Kir6.x/SUR2B, are key regulators of coronary tone and mutations in cardiac (Kir6.2/SUR2A) KATP channels result in heart disease. Here we explore the pathophysiological mechanism of a rare mutation (V734I) found in exon 17 of the ABCC9 gene, estimated to cause a 6.4-fold higher risk of AMI before the age of 60.

METHODS AND RESULTS

Eleven patients carrying the mutation were identified; they presented AMI of vasospastic origin associated with increased plasma levels of endothelin-1 and increased leukocyte ROCK activity. The effects of the mutation on the functional properties of the two splice variants of ABCC9 (SUR2A and SUR2B) were studied using patch-clamp electrophysiology. The mutation reduced the sensitivity to MgATP inhibition of Kir6.2/SUR2B channels but not of Kir6.2/SUR2A and Kir6.1/SUR2B channels. Furthermore, the stimulatory effects of MgNDP (MgADP, MgGDP and MgUDP) were unaltered in mutant Kir6.2/SUR2A and Kir6.1/SUR2B channels. In contrast, mutant channels composed of Kir6.2 and SUR2B were less sensitive to MgNDP activation, assessed in the presence of MgATP. The antianginal drug nicorandil activated Kir6.2/SUR2B-V734I channels, thus substituting for the loss of MgNDP stimulation, suggesting that this drug could be of therapeutic use in the treatment of AMI associated with V734I.

CONCLUSIONS

The 734I allele in ABCC9 may influence susceptibility to AMI by impairing the response of vascular, but not cardiac, KATP channels to intracellular nucleotides. This is the first human mutation in an ion channel gene to be implicated in AMI.

Post-mortem cardiac 3-T magnetic resonance imaging: visualization of sudden cardiac death?

OBJECTIVES

This study aimed to investigate post-mortem magnetic resonance imaging (pmMRI) for the assessment of myocardial infarction and hypointensities on post-mortem T2-weighted images as a possible method for visualizing the myocardial origin of arrhythmic sudden cardiac death.

BACKGROUND

Sudden cardiac death has challenged clinical and forensic pathologists for decades because verification on post-mortem autopsy is not possible. pmMRI as an autopsy-supporting examination technique has been shown to visualize different stages of myocardial infarction.

METHODS

In 136 human forensic corpses, a post-mortem cardiac MR examination was carried out prior to forensic autopsy. Short-axis and horizontal long-axis images were acquired in situ on a 3-T system.

RESULTS

In 76 cases, myocardial findings could be documented and correlated to the autopsy findings. Within these 76 study cases, a total of 124 myocardial lesions were detected on pmMRI (chronic: 25; subacute: 16; acute: 30; and peracute: 53). Chronic, subacute, and acute infarction cases correlated excellently to the myocardial findings on autopsy. Peracute infarctions (age range: minutes to approximately 1 h) were not visible on macroscopic autopsy or histological examination. Peracute infarction areas detected on pmMRI could be verified in targeted histological investigations in 62.3% of cases and could be related to a matching coronary finding in 84.9%. A total of 15.1% of peracute lesions on pmMRI lacked a matching coronary finding but presented with severe myocardial hypertrophy or cocaine intoxication facilitating a cardiac death without verifiable coronary stenosis.

CONCLUSIONS

3-T pmMRI visualizes chronic, subacute, and acute myocardial infarction in situ. In peracute infarction as a possible cause of sudden cardiac death, it demonstrates affected myocardial areas not visible on autopsy. pmMRI should be considered as a feasible post-mortem investigation technique for the deceased patient if no consent for a clinical autopsy is obtained.

Acute myocardial infarction and coronary vasospasm associated with the ingestion of cayenne pepper pills in a 25-year-old male

Capsaicin, one of the major active components of cayenne pepper pills, is an over-the-counter substance with sympathomimetic activity used commonly by young individuals for weight loss. Here we report the case of a previously healthy young male who developed severe chest pain after using cayenne pepper pills for slimming and sustained an extensive inferior myocardial infarction. Electrocardiography combined with a bedside transthoracic echocardiogram confirmed the diagnosis of acute myocardial infarction. The patient denied using illicit substances, and he had no risk factors for coronary artery disease. His medication history revealed that he had recently started taking cayenne pepper pills for slimming. A subsequent coronary angiogram revealed patent coronary arteries, suggesting that the mechanism was vasospasm. We postulate that the patient developed acute coronary vasospasm and a myocardial infarction in the presence of this known sympathomimetic agent. This case highlights the potential danger of capsaicin, even when used by otherwise healthy individuals.

Women have less severe and extensive coronary atherosclerosis in fatal cases of ischemic heart disease: an autopsy study

OBJECTIVE

The study aims to evaluate sex differences in extent and severity of coronary artery disease (CAD) and myocardial findings at autopsy among young people with fatal ischemic heart disease (IHD).

BACKGROUND

Women with acute coronary syndrome are less likely than men to display obstructive CAD at angiography. This suggests unique mechanisms of acute coronary syndrome exist in women or may reflect prehospital death of women with the most severe CAD.

METHODS

Reports of autopsies by the Office of the Chief Medical Examiner of New York City on people aged 21 to 54 years who died between January 1, 2006, and December 31, 2008, were reviewed. A total of 639 cases of death due to atherosclerotic or arteriosclerotic cardiovascular disease according to the medical examiner were analyzed. Significant CAD was defined as ≥75% cross-sectional area stenosis in an epicardial vessel or ≥50% left main.

RESULTS

Women were less likely to have obstructive CAD (63% vs 77% of men, P = .002). There was pathologic evidence of myocardial infarction (MI) in 43% of cases, 17% of which had nonobstructive CAD. Frequency of MI did not vary by sex overall (38% of women vs 45% of men, P = .18) or among those without significant CAD (23% vs 29%, P = .45).

CONCLUSIONS

Among young people determined at autopsy to have died of IHD, fewer women had obstructive CAD, consistent with angiographic data in other IHD syndromes. Pathologic evidence of MI may exist in the absence of obstructive CAD.

ST-segment elevation in non-atherosclerotic coronaries: a brief overview

The most common, clinically significant cause of ST elevation is an angiographically demonstrable occlusive disease due to atherosclerotic changes in coronary artery. Often, a patient presenting with non-specific complaints and ST-segment elevation on the electrocardiogram, is sent for a cardiac catheterization only to see no luminal stenosis on the angiogram. This clinical review is intended to inform emergency medicine physicians and internists about the conditions in which ST-segment elevation is accompanied with no atherosclerotic lesion on coronary angiography. These situations make a diverse array of conditions ranging from anomalous coronaries to anatomically normal coronaries with varied degrees of myocardial injury. These conditions are briefly reviewed in this article.

Acute intracoronary thrombosis in a normal coronary artery following coronary angiography: thromboaspiration using a guide catheter

A 60-year-old female presented with anterolateral non-ST elevation myocardial infarction and her coronary angiogram revealed severe left system coronary artery disease with a normal right coronary artery. Following coronary angiogram, she developed acute inferior wall and right ventricular ST elevation myocardial infarction with complete atrioventricular block and cardiogenic shock. Repeat coronary angiogram showed large proximal right coronary thrombus causing subtotal occlusion that was successfully aspirated using a guide catheter. The possible causes for intracoronary thrombosis following coronary angiography are discussed here.

Acute ST-segment elevation myocardial infarction due to a huge floating thrombus mimicking a myxoma in the left atrium

Acute ST-segment elevation myocardial infarction occurs when the blood supply to a coronary artery is completely interrupted. The most common cause of the abrupt occlusion of a coronary artery is the rupture of a vulnerable atherosclerotic plaque. However, embolisms from any sources can be another cause of abrupt coronary obstruction. The authors report a case of acute ST-segment elevation myocardial infarction caused by a huge left atrial thrombus mimicking a myxoma.

Acute myocardial infarction in the presence of normal coronaries and the absence of risk factors in a young, lifelong regular exerciser

Around 6% of patients suffering an acute myocardial infarction (AMI) have normal coronary arteries. The mechanisms responsible are not fully known, but include hypercoagulable state, coronary endothelial dysfunction, aortic dissection, inflammation, coronary thrombosis, aortic wall stiffening, cocaine abuse, carbon monoxide poisoning and paradoxical embolism. Here, the case of a lifelong regular exerciser without risk factors for cardiovascular disease who suffered an AMI with normal coronaries is reported. Despite normal cardiac function on left ventriculography and echocardiography, late gadolinium enhancement by cardiac magnetic resonance (CMR) revealed significant cardiac necrosis. The long-term prognosis is favourable with low rates of coronary morbidity and mortality. Acute chest pain should not be considered as benign and warrants medical investigation.

Non ST-segment elevation myocardial infarction in patient with essential thrombocythemia

A 68-year-old woman presented with acute chest pain and a greatly increased platelet count. Cardiac catheterization revealed subtotal occlusion and a thrombus-like filling defect in the right coronary artery. The patient was successfully treated with intravenous tirofiban. Essential thrombocythemia was diagnosed based on bone marrow findings, clinical presentation and laboratory analysis. The relationship between intracoronary thrombus and essential thrombocythemia is discussed.

Acute coronary syndrome presenting after pseudoephedrine use and regression with beta-blocker therapy

Pseudoephedrine, a common ingredient in cold relief drugs, dietary supplements and Chinese herbal tea, has potent sympathomimetic effects, impacting the cardiovascular system. The chemical properties and clinical effects of pseudoephedrine are similar to those of ephedrine, and its main effect is caused by the release of endogenous norepinephrine. A 45-year-old man who presented with chest pain following ingestion of pseudoephedrine--containing prescription medication is described. The patient was initially diagnosed with inferior myocardial infarction based on an electrocardiogram, and intravenous metoprolol was started pending coronary artery angiography. Metoprolol reversed the ST segment elevation and relieved the symptoms, and coronary angiography showed normal coronary arteries. The present case highlights beta-blocker therapy as part of an initial intervention of pseudoephedrine-related cardiac symptoms.

Coronary artery spasm as a frequent cause of acute coronary syndrome: The CASPAR (Coronary Artery Spasm in Patients With Acute Coronary Syndrome) Study

OBJECTIVES

This study was conducted to clarify the incidence of coronary spasm in emergency patients with suspected acute coronary syndrome (ACS) and acute chest pain at rest.

BACKGROUND

Chest pain at rest is a frequent symptom in the emergency room. Acute coronary syndrome is suspected in patients with elevation of cardiac markers, ischemic electrocardiographic changes, or simply typical clinical symptoms of unstable (usually resting) angina. However, of all patients with suspected ACS who undergo coronary angiography, up to 30% have nonobstructed coronary arteries. We sought to clarify how many of these patients suffer from coronary spasm as a possible cause of their chest pain.

METHODS

In a prospective study from June to December 2006, all patients with suspected ACS who underwent coronary angiography and had no culprit lesion underwent intracoronary provocation with acetylcholine. The ACH testing was considered positive at a vasoconstriction of >/=75% relative to the diameter after intracoronary nitroglycerine when the initially reported symptoms could be reproduced.

RESULTS

Of 488 consecutive patients, 138 had no culprit lesion (28%). Twenty-two were found to have another diagnosis. The ACH testing was performed in 86 of the remaining 116 patients. In 42 patients, coronary spasm was verified (49%).

CONCLUSIONS

Every fourth patient with ACS had no culprit lesion. Coronary spasm could be documented in nearly 50% of the patients tested by ACH. Coronary spasm is a frequent cause of ACS and should regularly be considered as a differential diagnosis.

Thrombotic occlusion proximal to plaque rupture in acute myocardial infarction: evaluation by intravascular ultrasound and coronary angioscopy

A 56-year-old man was admitted because of acute myocardial infarction for 10 h of onset. Emergent coronary angiography showed a total occlusion at the middle portion of the right coronary artery. After aspirating thrombus, high-grade stenosis was present in the distal segment. Angioscopy showed only a white thrombus, but not a yellow plaque nor a red thrombus at the initially occluded site. On the other hand, IVUS demonstrated large attenuation indicating a lipid core and cavity obstruction and angioscopy revealed a glittering yellow plaque and red thrombi in the distal segment. Precipitation of thrombus from the distal site to the middle site might have occurred. IVUS and angioscopy might be effective for detecting and evaluating the infarct-related vulnerable plaque and for making the therapeutic strategy when percutaneous coronary interventions are performed.

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.

Dual intoxication with diazepam and amphetamine: This drug interaction probably potentiates myocardial ischemia

Drug-induced myocardial infarction is not a common phenomenon and the underlying mechanism has been related with the coronary artery spasm in the majority of cases. It is mainly related to illicit substances such as cocaine, ecstasy, LSD and amphetamine. According to the findings in the literature, it is most likely that myocardial ischemia due to amphetamine abuse is a result of combined mechanisms which include coronary artery vasospasm, and in lesser extent thrombus formation or direct myocardial toxicity. Diazepam is also usually found as a substance of abuse. Recent findings indicate that diazepam exerts an inhibitory activity on different isoforms of the enzyme cyclic nucleotide phosphodiesterase, which can be found in the heart muscle and also show that diazepam potentate the positive inotropic effect of both noradrenaline and adrenaline, which subsequently leads to increase in myocardial contractility. We propose that dual intoxication with amphetamine and benzodiazepine potentate their effects on cardiac tissue and coronary arteries which results in larger myocardial injury.

Prevalence of normal coronary angiography in the acute phase of suspected ST-elevation myocardial infarction: experience from the PRAGUE studies

BACKGROUND

Acute ST-elevation myocardial infarction in patients with normal coronary arteries has previously been described, but coronary angiography in these patients was performed after the acute phase of the infarction. It is possible that these patients did not have normal angiograms during the acute phase (transient coronary thrombosis or spasm were usually suspected to be the cause). Information on the prevalence of truly normal coronary angiograms during the acute phase of a suspected ST-elevation myocardial infarction is lacking.

PATIENTS AND METHODS

The Primary Angioplasty in patients transferred from General community hospitals to specialized PTCA Units with or without Emergency thrombolysis-1 (PRAGUE-1) and PRAGUE-2 studies enrolled 1150 patients with ST-elevation acute myocardial infarction, in whom 625 coronary angiograms were performed within 2 h of the initial electrocardiogram. A simultaneous registry included an additional 379 coronary angiograms performed during the ST-elevation phase of a suspected myocardial infarction. Thus, a total of 1004 angiograms were retrospectively analyzed. A normal coronary angiogram was defined as one with the absence of any visible angiographic signs of atherosclerosis, thrombosis or spontaneous spasm.

RESULTS

Normal coronary angiograms were obtained for 26 patients (2.6%). Among these, the diagnosis at discharge was a small myocardial infarction in seven patients (0.7%), acute (peri)myocarditis in five patients, dilated cardiomyopathy in four patients, hypertension with left ventricular hypertrophy in three patients, pulmonary embolism in two patients and misinterpretation of the electrocardiogram (ie, no cardiac disease) in five patients. Seven patients with small infarctions underwent angiography within 30 min to 90 min of complete relief of the signs of acute ischemia, and thus, angiograms during pain were not taken. None of the 898 patients catheterized during ongoing symptoms of ischemia had a normal coronary angiogram. Spontaneous coronary spasm as the only cause (without underlying coronary atherosclerosis) for the evolving infarction was not seen among these 898 patients. Thus, the causes of the seven small infarcts in patients with normal angiograms remain uncertain.

CONCLUSIONS

The observed prevalence of normal coronary angiography in patients presenting with acute chest pain and ST elevations was 2.6%. Most of these cases were misdiagnoses, not infarctions. A normal angiogram during a biochemically confirmed infarction is extremely rare (0.7%) and was not seen during the ongoing symptoms of ischemia.

Crack cocaine causing fatal vasoconstriction of the aorta

Cocaine is the most powerful central nervous stimulant found in nature. All forms of cocaine cause tachycardia and vasoconstriction. A smokable, rapidly reacting form of cocaine base, "crack," is highly addictive. Smoking crack introduces a high concentration of cocaine into the bloodstream, rendering it especially dangerous. We report a case that visually demonstrates severe aortic vasoconstriction from the suprarenal aorta and extending to both femoral arteries and beyond, resulting in renal failure and fatal bowel ischemia after a 5-day binge of crack cocaine.

Acute myocardial infarction associated with heavy alcohol intake in an adolescent with normal coronary arteries

Acute ingestion of large quantities of alcohol is known to be able to trigger acute myocardial infarction. A 19-year-old boy presented at the emergency department of our hospital with complaints of severe retrosternal chest pain. One night before this event, he had drunk large amounts of alcohol. The level of alcohol in his blood was measured at 0.59 grams per litre. A 12-lead electrocardiogram showed elevations of the ST segment, averaging from 2 to 10 millimetres, in leads V1-6, DI and aVL. Since consumption of alcohol is very common in the community, the triggering effect of binge-drinking and consumption of large amounts of alcohol on acute myocardial infarction should be considered as a crucial subject for public health so as to raise the consciousness of the population, especially young persons.

Ergonovine test in angina with normal coronary arteries. Is it worth doing it?

BACKGROUND

Patients with angina and normal coronary arteries are often misdiagnosed with having non-cardiac pain. Although vasospasm is a well-known entity, spasm provocation is not routinely done in the majority of hospitals at present.

MATERIALS AND METHODS

One hundred and sixty two consecutive patients with thoracic pain and normal coronary arteries were retrospectively studied. The characteristics of pain were analysed. One hundred and sixty one non-invasive tests (with and without imaging) were done to 126 patients before angiography. Increasing doses of ergonovine (from 1 to 30 microg) were injected into the coronary arteries to provoke coronary spasm. The correlation between ergonovine-induced spasm and non-invasive tests was studied.

RESULTS

Oppressive thoracic pain suggestive of angina was present in 144 patients. It occurred at rest in 59 patients, only at night in 14, with effort in 40, and it was mixed in 31. Non-oppressive atypical pain was reported by 18 patients. Non-invasive tests were 94 positive, 60 negative and 7 non-diagnostic. Ergonovine test elicited coronary spasm in 85 patients (52.5%). No significant correlation was found between the positivity of a non-invasive test and ergonovine-induced spasm.

CONCLUSIONS

More than half of the patients with angina and normal coronary arteries can be diagnosed with vasospastic angina if ergonovine test is performed. Even patients with a negative non-invasive test maybe sent to coronary angiography when vasospastic angina is suspected, in order to have an accurate diagnosis.

Obesity: a risk factor for acute myocardial infarction with angiographically patent epicardial coronary vessels in an adolescent

OBJECTIVE

Toreport a causal relationship between myocardial infarction (MI) and obesity in an adolescent in the absence of the well-known risk factors for MI.

CASE PRESENTATION AND INTERVENTION

A morbidly obese 17-year-old male, a nonsmoker, nondiabetic and normotensive patient, who sustained acute inferior MI with no family history of coronary artery disease, presented with central chest pain. ECG showed low voltage, normal sinus rhythm and ST segment elevation in the inferior leads; cardiac enzymes were elevated. Screening for ethanol and cocaine were negative. He was admitted to the coronary-care unit as a case of inferior MI with late presentation. Cardiac catheterization revealed patent epicardial coronary arteries; short- and long-term plans for weight reduction and family counseling were started. The hospital stay was uneventful, and the patient was discharged home on the fourth day.

CONCLUSION

Based on clinical and laboratory findings, we assume that the MI might partly be secondary to coronary artery spasm or invisible premature atherosclerotic plaques. Public education and awareness for this complication in a young obese patient are warranted.

Cocaine-associated chest pain

Current estimates establish that more than 30 million people in the United States use cocaine. Cardiovascular complaints commonly occur among patients who present to emergency departments(EDs) after cocaine use, with chest pain the most common complaint in several studies. Although myocardial ischemia and infarction account for only a small percentage of cocaine-associated chest-pain, physicians must understand the pathophysiology of cocaine and appropriate diagnostic and treatment strategies to best manage these patients and minimize adverse outcomes. This article reviews the pharmacology of cocaine, its role in the pathogenesis of chest pain with specific emphasis on inducing myocardial ischemia and infarction, and current diagnostic and management strategies for cocaine-associated chest pain encountered in the ED.

Normal angiogram in acute coronary syndrome-preangiographic risk stratification, angiographic findings and follow-up

BACKGROUND

Coronary angiographies performed during acute coronary syndrome show different coronary morphologies-vessel occlusions, thrombi and various types of stenoses. In a few cases of acute coronary syndrome, angiography reveals normal coronary arteries. It is the purpose of this study to analyze this specific subset of patients who presented with an acute coronary syndrome but had a normal coronary angiogram with respect to the preangiographic diagnostics, risk stratification and clinical follow-up.

METHODS AND RESULTS

A total of 897 coronary angiographies were performed as an emergency procedure in our institution. The majority of patients (n = 821) presented with coronary artery disease and the majority was treated by mechanical revascularization (86.3%). In 76 patients (8.5%), no coronary artery stenosis was documented. However, according to the preangiographic risk stratification, coronary artery disease was expected in these patients. Observations documented angiographically included coronary spasms (6.6%) and muscle bridges (5.3%). During a mean follow-up of 11.2 +/- 6.4 months, one patient developed an acute myocardial infarction requiring coronary intervention. All other patients were free of any cardiac event.

CONCLUSIONS

In summary, we have to consider that coronary angiography may not always detect the cause of myocardial ischemia in every patient. There is a small group of patients with normal coronary angiograms during acute coronary syndrome. Additional diagnostic procedures like intravascular ultrasound (IVUS) or the assessment of intracoronary physiological parameters may increase the diagnostic value of angiography.

Spinal cord stimulation for refractory angina pectoris: a retrospective analysis of efficacy and cost-benefit

BACKGROUND

Patients with refractory angina pectoris have severe symptoms despite optimal medication, but are not suitable for revascularisation. Spinal cord stimulation (SCS) has been used for treating refractory angina pectoris since 1985. The efficacy of SCS has been proven by randomised controlled trials and follow-up studies have shown that SCS is a safe treatment. The objective of the current study was to retrospectively analyse the clinical outcomes and cost-benefit of SCS in patients with refractory angina pectoris.

METHODS

Eighteen months after SCS implantation, the effects on Canadian Cardiovascular Society (CCS) functional level and acute symptom relief of 24 patients with permanent SCS were analysed by review of medical records. Nineteen of these 24 patients were able to report their anginal frequency, nitroglycerin consumption and subjective perception on physical activity and quality of life.

RESULTS

Angina frequency decreased from a median of 14.0 to 2.3 attacks/week (p < 0.01). Nitroglycerin intake decreased from a median of 27.5 to 1.5 doses/week (p < 0.01). Canadian Cardiovascular Society angina class improved from a median of three to two (p < 0.001). During a three-year period before SCS implantation, the hospitalisation rate and duration related to coronary artery disease increased progressively. The duration of hospitalisation increased from a median of three to 10 days/patient/year. In the year after SCS implantation the duration of hospitalisation decreased to a median of 0 day/patient/year (p < 0.001). The cost of hospital care due to coronary artery disease decreased significantly thereafter. The total cost of SCS procedure was recovered within 16 months after implantation, which is less than 40% of the device life span.

CONCLUSIONS

This retrospective study indicates that SCS treatment alleviates angina symptoms and improves quality of life. The treatment is also effective in preventing hospitalisations and saving costs in hospital care. A prospective study is warranted to confirm the current observations.

Large myocardial infarction and a severe spasm of the left coronary artery

In patients presenting with an acute myocardial infarction, normal coronary arteries in the first coronary angiography lead to diagnostic uncertainty. We report the case of a 41-year-old woman with an acute anterior infarction and a severe spasm of the left coronary artery, which was treated with intracoronary nitroglycerine and verapamil. The new technique of contrast-enhanced cardiac magnetic resonance imaging was used to confirm the diagnosis.

Treatment of intracoronary thrombus using tirofiban in a patient with normal coronary arteries

We report a 64-year-old Turkish man who presented with unstable angina pectoris. Coronary angiography revealed massive intracoronary thrombus, which completely occluded the distal part of the left circumflex coronary artery. The thrombotic segment and the rest of the coronary tree were free of atherosclerosis. The patient was treated with intravenous tirofiban, a glycoprotein IIb/IIIa inhibitor. A control angiography was performed one week later and showed total dissolution of the thrombus with tirofiban therapy.

Three Cases of Acute Myocardial Infarction Due to Coronary Embolism: Treatment Using a Thrombus Aspiration Device

In this report, we describe three patients with acute myocardial infarction due to coronary embolism who were successfully treated using a thrombus aspiration device. Thrombus aspiration is shown to be a feasible and effective strategy for the treatment of acute coronary embolism.

Reversible myocardial dysfunction, a possible complication in critically ill patients without heart disease

PURPOSE

Reversible myocardial dysfunction or myocardial stunning is frequently described in patients with episodes of acute coronary syndrome and has recently been reported in critically ill patients without ischaemic heart disease. This article presents a study and description of the possible existence of myocardial dysfunction in critically ill patients in our setting who present no acute episode or history of cardiovascular disease.

DESIGN

Prospective, descriptive study.

SETTING

The intensive care unit of a district hospital.

PATIENTS AND PARTICIPANTS

The study included all patients admitted to the intensive care unit between March 1998 and March 2001 for noncardiac causes and with no history of heart disease, and who underwent echocardiographic examination for electrocardiographic changes, signs of cardiac insufficiency, persistent arrhythmias, or any other indication. Patients with sepsis or other critical illness known to be associated with myocardial dysfunction were excluded from the study. The study was carried out on those selected patients who developed myocardial dysfunction.

MEASUREMENTS AND RESULTS

Transthoracic and transoesophageal echocardiography were carried out to assess the left ventricular ejection fraction and any segmental contractility disturbances. These investigations were carried out within 24 hours of admission, during the first week, during the second or third week, after one month and after three to 6 months. The electrocardiogram was assessed on admission and the changes over time were studied. Thirty-three patients were included in the study after detecting myocardial dysfunction; the median age of these patients was 63 years [range, 23-82 years]. Seven patients died. The median initial left ventricular ejection fraction was 0.34 [range, 0.16-0.48] and improved with time. Segmental contractility disturbances were detected initially in all patients and also normalized with time. All patients presented electrocardiogram changes that normalised in line with the echocardiographic changes.

CONCLUSIONS

Reversible myocardial dysfunction can be develop in critically ill patients without primary heart disease. This syndrome is associated with systolic dysfunction, segmental contractility disturbances and electrocardiographic changes.

Myocardial infarction resulting from nonatherosclerotic coronary artery diseases

Myocardial infarction (MI) infrequently results from nonatherosclerotic coronary diseases such as coronary embolism, spasm, dissection, and arteritis. If these disorders are not considered in the differential diagnosis of MI, specific beneficial therapies would be overlooked. Because physicians see large number of patients with MI during their career, the likelihood that they will encounter patients with MI resulting from nonatherosclerotic diseases is high. Two cases are presented to highlight different etiologies and treatment approaches of nonatherosclerotic MI.

Alcohol-triggered acute myocardial infarction

Heavy alcohol drinking may trigger the onset of acute myocardial infarction. Although the underlying mechanisms are poorly understood, alcohol-induced changes in blood homeostasis, endothelial dysfunction, decreased fibrinolysis, and coronary spasm are the possible explanations. There are rare reports of acute myocardial infarction in young individuals triggered by acute heavy alcohol intake. We present a case of acute ST segment elevation myocardial infarction triggered by heavy alcoholic binge drinking in a man and discuss the available explanations of this rare association.

An acute clinical trial evaluating the cardiovascular effects of an herbal ephedra-caffeine weight loss product in healthy overweight adults

OBJECTIVE

This study was undertaken to determine the acute effects of a commercial weight loss supplement containing herbal ephedrine and caffeine on cardiovascular function in healthy overweight adults.

DESIGN

Randomized double blind clinical trial evaluating the cardiovascular effects of an ephedra-caffeine (Xenadrine(TM); XEN) based herbal product vs placebo (PLA).

SUBJECTS

Twenty-seven healthy overweight adults (age 21-60 y; body mass index > or = 25 kg/m(2)).

MEASUREMENTS

Systolic and diastolic blood pressure, heart rate, serial electrocardiograms (EKG) and Doppler echocardiograms.

RESULTS

A comparison of means between the groups indicated no statistically significant differences at the start of the study for the variables above. There were no serious adverse events. When examining the effects of XEN vs PLA on cardiovascular health/function, there were no significant effects observed in heart rate, systolic blood pressure, diastolic blood pressure, left ventricular ejection fraction, heart valve function or in cardiovascular physiology within the parameters measured.

CONCLUSION

These findings indicate that, over a 14-day period, ingestion of the commercial weight loss supplement in a healthy overweight population did not produce any noticeable cardiovascular side effects.