Abnormal Electrocardiogram Changes Research Articles

Anthracycline-induced arrhythmias in breast cancer therapy: A meta-analysis of single-arm trials.

As of 2020, breast cancer has emerged as the predominant cause of cancer incidence globally. Anthracycline-based chemotherapy serves as a crucial element in the treatment regimen for breast cancer. However, these anthracycline-based drugs are associated with cardiac toxicity. This study represents the first clinical quantitative analysis aimed at accurately determining the incidences of arrhythmia and abnormal electrocardiogram (ECG) changes, thereby providing valuable data to bolster clinical drug usage and monitoring. A systematic search was conducted across multiple databases including CNKI, VIP, Wanfang, PubMed, Embase, Web of Science, and the Cochrane Library. The incidence of combined arrhythmias in breast cancer patients and the associated heterogeneity were calculated using either a random effect model or a fixed effect model. Statistical analysis was performed using STATA16. The study encompassed a total of 37 articles, which included 5705 breast cancer patients undergoing anthracycline treatment. Among these patients, 2257 developed arrhythmias. The meta-analysis revealed that the incidence of anthracycline-associated arrhythmias and abnormal ECG changes in breast cancer patients was 0.41 (0.37, 0.44). Subgroup analysis indicated that the incidence of ST-T segment change was 0.19 (0.15, 0.23), the incidence of conduction block was 0.04 (0.02, 0.05), the incidence of premature beats was 0.09 (0.07, 0.11), and the incidence of atrial fibrillation was 0.04 (0.00, 0.12). Additional results are presented in Table 3. This pioneering study accurately assesses the incidence of arrhythmias in breast cancer patients treated with anthracyclines. The findings provide clinicians with valuable insights into understanding and managing the cardiac toxicity associated with such treatment. Moreover, this study lays the foundation for future research exploring the mechanisms underlying these arrhythmias and potential preventative strategies.

ECG pattern among adult patients on antipsychotic medications at the university of port Harcourt teaching hospital, River State, Nigeria

Background: Antipsychotic medications treat neuropsychiatric disorders like Schizophrenia and Bipolar disorder. Despite their symptom management benefits, they carry cardiovascular risks. Electrocardiogram (ECG) monitoring is crucial for detecting abnormalities. This research aims to identify and understand these risks, aiding healthcare professionals in implementing effective monitoring for better patient outcomes. Methods: A retrospective study on subjects who are patients on Antipsychotic medications from the University of Port Harcourt Teaching Hospital (UPTH). Results: In a study with 100 patients on antipsychotic medications, 68% displayed abnormal ECG changes during treatment, while 32% had normal patterns. Left Ventricular Hypertrophy (LVH) and Atrial Enlargements were common, affecting 30% and 26% respectively, while QT interval prolongation was rare (2%). Risperidone, Sodium Valproate, and Trihexyphenidyl showed the most abnormal ECG changes, whereas Olanzapine, Fluoxetine, and Escitalopram were relatively safer. Conclusion: ECG monitoring is an essential component of the management of patients on antipsychotic drugs. It enables the early detection of QT interval prolongation and other cardiac abnormalities, allowing for timely interventions and personalized treatment plans. Our study showed just 2% of the patient had QT interval prolongation, however Left Ventricular Hypertrophy was a common finding in the ECG of the patients, 30%.

Abstract 15206: Significance of Electrocardiogram Changes With Exercise in Pediatric Pectus Excavatum

Introduction: The change in cardiac position caused by the thoracic deformity in patients with pectus excavatum (PEX) produces characteristic electrocardiogram (ECG) findings. However, the significance of ECG changes during exercise is unknown. Hypothesis: The ECG changes with exercise in PEX are related to worsening severity of PEX and location of PEX in relation to the heart. Methods: This was a retrospective review of patients ≤19 years old that underwent an institution-based protocol for preoperative PEX evaluation with ECG, echocardiogram (TTE), chest computerized tomography (CT) and cardiopulmonary exercise test (CPET) between January 2015 and December 2021. ECG changes with exercise were compared to the severity of PEX as defined by the Haller index (HI; mild = 2-3.2, moderate = 3.2-3.5, severe > 3.5) and location of the PEX as determined by right ventricular compression on CT. ECG changes were also compared to tricuspid valve annulus size (TVAS) on TTE and resting heart rate (HR) and HR reserve on CPET. Pearson's χ2 was used to compare categorical variables. Two-sample T-test was used to compare categorical with continuous variables. Results: There were 124 patients (85% male; median age 15 years [10-19 years]) with median HI 3.7 (2.4-20). Abnormal ECG changes with exercise were seen in 33 % of patients. Premature ventricular complexes (PVC) were the most frequently encountered (n=30; 73%). There was no significant difference in severity of PEX in patients with PVCs [χ2 =0.93, p 0.33; median HI of 3.9 (IQR 1.6) vs 3.7 (IQR 1.4)]. The majority of patients (96%) with PVCs had evident right ventricular compression on CT (χ2 = 5.20, p 0.02). Similarly, those with abnormal ECG changes with exercise were more likely to have a lower TVAS in comparison to those without [χ2 = 4.17, p 0.04; median TVAS z score -2.06 (IQR 1.22) vs -2.32 (IQR 0.75)]. The CPET indices were not significantly different between the two groups. Conclusions: The most frequent ECG abnormality seen with exercise in PEX in this cohort is PVCs. Lower TVAS and right ventricular compression on CT were significantly correlated with the development of PVCs with exercise. Follow-up evaluation of ECG during CPET after PEX repair may help affirm resolution of ectopy.

Penetrating Atherosclerotic Ulcer with Elevated Troponin in A Patient with Old Myocardial Infarction: A Case Report

Penetrating atherosclerotic ulcer (PAU), an uncommon etiology of acute aortic syndrome (AAS), is a potential cause of chest pain seen in emergency departments. As PAU may lead to electrocardiogram (ECG) changes or rarely, elevated troponin levels, it is most likely misdiagnosed as acute coronary syndrome (ACS). Hence, individuals with PAU may be offered potentially life-threatening treatment. This paper reports a case of a 81-year-old male who presented with intermittent chest pain with a history of old inferior myocardial infarction and stent placement in the left circumflex coronary artery (LCX) three years ago. Initially, he was diagnosed with non-ST-elevation myocardial infarction (NSTEMI) based on abnormal ECG changes and raised troponin I. However, emergency coronary angiography (CAG) showed no restenosis in the left circumflex coronary artery (LCX) but with mild stenosis in the left anterior descending artery (LAD) and right coronary artery (RCA). Computed tomographic angiography (CTA) of the whole aorta showed multiple atherosclerotic plaques with penetrating atherosclerotic ulcer in the aortic arch and descending aorta. Endovascular aortic repair with Ankura II covered stent was performed. This case study reminds us that it is clinically difficult to distinguish PAU from ACS. Upon excluding ACS from the diagnosis, we should take into consideration of PAU, especially in elderly patients with positive cTnI.

Differential Effect of Three Macrolide Antibiotics on Cardiac Pathology and Electrophysiology in a Myocardial Infarction Rat Model: Influence on Sodium Nav1.5 Channel Expression.

Macrolides were reported to have cardiotoxic effects presented mainly by electrocardiogram (ECG) changes with increased risk in cardiac patients. We aimed to determine the impact of three macrolides, azithromycin, clarithromycin and erythromycin, on cardiac electrophysiology, cardiac enzyme activities, histopathological changes, and sodium voltage-gated alpha subunit 5 (Nav1.5) channel expression. We used eight experimental groups of male albino rats: vehicle, azithromycin (100 mg/kg), clarithromycin (100 mg/kg), erythromycin (100 mg/kg), MI + vehicle, MI + azithromycin (100 mg/kg), MI + clarithromycin (100 mg/kg) and MI + erythromycin (100 mg/kg); each group received chronic oral doses of the vehicle/drugs for seven weeks. ECG abnormalities and elevated serum cardiac enzymes were observed particularly in rats with AMI compared to healthy rats. Microscopic examination revealed elevated pathology scores for rats treated with clarithromycin in both experiments following treatment with erythromycin in healthy rats. Although rats with MI did not show further elevations in fibrosis score on treatment with macrolides, they produced significant fibrosis in healthy rats. Downregulation of cardiac Nav1.5 transcript was observed following macrolides treatment in both groups (healthy rats and rats with MI). In conclusion, the current findings suggested the potential cardiotoxic effects of chronic doses of macrolide antibiotics in rats with MI as manifested by abnormal ECG changes and pathological findings in addition to downregulation of Nav1.5 channels. Furthermore, in the current dose ranges, azithromycin produced the least toxicity compared to clarithromycin and erythromycin.

Prevalence of abnormal and borderline electrocardiogram changes in 13, 079 Chinese amateur marathon runners

BackgroundThe 12-lead electrocardiogram (ECG) has been adopted as an important component of preparticipation cardiovascular screening. However, there are still controversies in the screening and few studies with a large sample size have reported the results of ECGs of marathon runners. Therefore, the purpose of this study was to assess the prevalence of normal, borderline, and abnormal ECG changes in marathon runners.MethodsThe 12-lead ECG data of 13,079 amateur marathon runners between the ages of 18 and 35 years were included for analysis. The prevalence of ECG abnormalities among different gender groups was compared with chi-square tests.ResultsIn terms of training-related changes, sinus bradycardia, sinus arrhythmia, and left ventricular high voltage were found in approximately 15, 5, and 3.28% of the participants, respectively. The incidence of right axis deviation in the marathon runners was 1.78%, which was slightly higher than the incidence of left axis deviation (0.88%). No more than 0.1% of the amateur marathon runners exhibited ST-segment depression, T wave inversion (TWI), premature ventricular contraction, pathologic Q waves, and prolonged QT interval.ConclusionsTraining-related ECG changes, including sinus bradycardia, sinus arrhythmia, and left ventricular high voltage, were common in amateur marathon runners. Most abnormal ECG changes, including ST-segment depression, TWI, premature ventricular contraction, pathologic Q waves, and prolonged QT interval, were infrequently found in amateur marathon runners. The data also suggested Chinese amateur marathon runners may have a relatively lower prevalence of ECG abnormalities than black and white runners.

Cardiac Disease Associated Genetic Variants in Yi Nationality in Regions with High Incidence of Yunnan Sudden Unexplained Death.

Objective To explore the association of cardiac disease associated genetic variants and the high incidence of Yunnan sudden unexplained death （YNSUD） in Yi nationality. Methods The genomic DNA was extracted from peripheral blood samples collected from 205 Yi villagers from YNSUD aggregative villages （inpatient group） and 197 healthy Yi villagers from neighboring villages （control group）. Fifty-two single nucleotide variants （SNVs） of 25 cardiac disease associated genes were genotyped using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry （MALDI-TOF-MS）. The SPSS 17.0 was used to analyze data. The pathogenicities of variants with differences between the two groups that have statistical significance were predicted by protein function prediction software PolyPhen-2 and SIFT. All villagers from inpatient group were given electrocardiogram （ECG） examination using a 12-lead electrocardiograph. Results The allele frequency and the genotype frequency of missense mutation DSG2 （rs2278792, c.2318G>A, p.R773K） of pathogenic genes of arrhythmogenic right ventricular cardiomyopathy （ARVC） in inpatient group was higher than that in control group （P<0.05）. Abnormal ECG changes were detected in 71 individuals （34.6%） in the inpatient group, among which 54 individuals carried R773K mutation, including clockwise （counterclockwise） rotation, left （right） axis deviation, ST segment and T wave alteration and heart-blocking. Conclusion Definite pathogenic mutations have not been found in the 52 cardiac disease genes associated SNVs detected in Yi nationality in regions with high incidence of YNSUD. The cause of high incidence of YNSUD in Yi nationality needs further study.

Identifying Electrocardiogram Pattern Changes and Their Association with Echocardiography among Malaysian Footballers Attending PreParticipation Evaluation

Introduction: Sudden cardiac death is the most common medical cause of death in athletes. The aim of this study was to identify the electrocardiogram (ECG) pattern changes and its association with echocardiography among Malaysian footballers during a pre-participation evaluation (PPE). Methods: A retrospective study was conducted on footballers attending a PPE at a primary care centre. Secondary data collection was conducted and the proforma included clinical history, physical examination, ECG, Echocardiogram and cardiovascular riskfactors assessment such as heart rate, blood pressure, lipid profile, fasting blood sugar and creatinine. Data were extracted from the medical records, echocardiogram report and the original ECG. The ECG patterns were analysed according to the International consensus for ECG interpretation in athletes to determine physiological versus pathological changes. The data was analysed using SPSS v24. Results: This study included 85 male Malaysian footballers with a mean age of 20.1 ± 3.0 years. The mean resting heart rate was 55.2 ± 9.3beats per minute. Abnormal ECG changes were found in 20% of the participants, which were higher compared to that reported in other studies (14% – 17.3%). The normal ECG findings in athletes were sinus bradycardia (76.5%), J-point elevation (68.2%), prolonged PR interval (3.5%) and incomplete right bundle branch block (4.7%). The abnormal ECG changes were multiple T wave inversions (5.9%), hypertrophy (2.4%), and deep Q-waves (8.2%). Four abnormal ECGs were consistent with abnormal echocardiography findings and out of these,two ECGs with hypertrophic changes were consistent with mild inter atrial septal bulging and apical hypertrophy. Conclusions: Malaysian footballers have ECG changes that are consistent with physiological changes in athlete’s heart. The positive association between ECG and Echocardiogram findings are useful in confirming pathological ECG changes. Physicians should be trained in PPE protocol and ECG interpretation in athletes in order to improve identification of those at risk of sudden cardiac death.

Electrocardiographic findings in human immunodeficiency virus-infected children in Benin City, Nigeria.

Human immunodeficiency virus (HIV) infection is a global pandemic affecting mostly sub-Saharan Africa. It is a multisystem disease. Cardiovascular involvement detected by electrocardiogram (ECG) has been described mostly in adult populations with few studies on children. In this study, the ECG findings of HIV-infected as against HIV-uninfected children were evaluated. This comparative cross-sectional study was conducted in two public hospitals in Benin City. Using convenience sampling, 200 each of HIV-positive children attending the HIV clinics of both hospitals and age- and sex-matched HIV-negative children attending follow-up clinics in the same hospitals were recruited. Biodata/sociodemographic information was obtained, while each participant underwent 12-channel ECG evaluation. The prevalence of abnormal ECG findings in HIV-positive children was 34.5% compared to 4.5% in HIV-negative children (P < 0.0001). The mean PR, QRS and QT intervals in the participants were 0.13 ± 0.02 s, 0.11 ± 0.15 s and 0.41 ± 0.03, respectively. They were statistically significantly longer than controls, 0.12 ± 0.02 s, 0.08 ± 0.09 s and 0.40 ± 0.02 s, respectively, P < 0.05, in each case. The prevalence of prolonged PR, QRS and QTc was significantly higher in the patients, 5%, 3.5% and 3.5%, respectively, than controls, 05, 0% and 0%, respectively (P < 0.05 in each case). A third of the HIV-infected children in the study had abnormal ECG changes. It is recommended that ECG be included in their routine management of HIV-positive children so as to better supervise the affected children, retard the deterioration and improve their quality of health.

Silent Left Large Atrial Myxoma: A Patient with Serial Electrocardiogram Variation.

Cardiac myxoma is often discovered as an incidental finding and presents with various subtle symptoms and signs. Electrocardiographic findings are mostly non-specific. Atrial flutter or conduction abnormalities are known to be rare. We report a case of large left atrial myxoma that was diagnosed by transthoracic echocardiography at a primary care clinic. An asymptomatic, 71-year-old woman presented with serial abnormal electrocardiogram changes during a routine consultation. A diagnosis of left atrial myxoma was obtained through transthoracic echocardiography. We report this case with a review of literature on cardiac myxoma associated with arrhythmia.

Chest pain after percutaneous coronary intervention in patients with stable angina

BackgroundPercutaneous coronary intervention (PCI) has been widely used to treat acute coronary syndrome but is only recommended as an additional treatment to medical therapy and risk modification in patients with refractory or progressing angina. The number of PCI in this patient population is still increasing. Post-PCI chest pain (PPCP) is one of the common problems of PCI. Its presentation and causes in patients with stable angina are poorly understood.Patients and methodsThis study retrospectively collected clinical information of 167 patients who had stable angina and underwent elective PCI, including 70 patients with PPCP 24 hours after procedure and 97 patients without PPCP. The incidence and predictors of PPCP were analyzed.ResultsThe incidence of PPCP was 41.9% (70/167). Compared with non-PPCP patients, PPCP patients had more abnormal post-PCI electrocardiogram (ECG) changes (new Q-waves, ST-segment shifts, or T-waves inversion) and serum cardiac troponin I (cTnI) elevation, more PCI vessels, and stent placement (all P<0.05). More PPCP patients required repeat revascularization than non-PPCP patients after PCI (P=0.043). PPCP was correlated with abnormal post-PCI ECG changes (P<0.0001), cTnI elevation (P<0.0001), post-PCI serum level of cTnI (P<0.0001), number of stents placed (P=0.009), and pre-PCI cTnI level (P=0.049). The strongest predictors of PPCP were abnormal post-PCI ECG changes (P<0.0001), post-PCI cTnI level (P<0.0001), and cTnI elevation (P<0.0001), followed by the number of stents placed (P=0.048).ConclusionPPCP is common in patients with stable angina in our cohort. It is associated with abnormal ECG changes, cTnI elevation, and number of stents placed.

The prevalence of abnormal ECG in trained sportsmen

BackgroundCompetitive sports training causes structural and conductive system changes manifesting by various electrocardiographic alterations. We undertook this study to assess the prevalence of abnormal ECG in trained Indian athletes and correlate it with the nature of sports training, that is endurance or strength training. MethodsWe evaluated a standard resting, lying 12 lead Electrocardiogram (ECG) in 66 actively training Indian athletes. Standard diagnostic criteria were used to define various morphological ECG abnormalities. Results33/66 (50%) of the athletes were undertaking endurance training while the other 33 (50%) were involved in a strength-training regimen. Overall 54/66 (81%) sportsmen had significant ECG changes. 68% of these changes were considered as normal training related features, while the remaining 32% were considered abnormal. There were seven common training related ECG changes–Sinus Bradycardia (21%), Sinus Arrhythmia (16%), 1st degree Atrioventricular Heart Block (6%), Type 1 2nd-degree Atrioventicular Heart Block (3%), Incomplete Right bundle branch block (RBBB) (24%), Early Repolarization (42%), Left Ventricular Hypertrophy (LVH) (14%); while three abnormal ECG changes--T-wave inversion (13%), RBBB(4%), Right ventricular hypertrophy (RVH) with strain (29%) were noted. Early repolarization (commonest change), sinus bradycardia, and incomplete RBBB were the commoner features noticed, with a significantly higher presence in the endurance trained athletes. ConclusionA high proportion of athletes undergoing competitive level sports training are likely to have abnormal ECG recordings. Majority of these are benign, and related to the physiological adaptation to the extreme levels of exertion. These changes are commoner during endurance training (running) than strength training (weightlifting).

Removal of temporary pacemaker after cardiac surgery in infants: A harmless procedure?

External pacemakers (PM) via temporary epicardial leads are routinely applied to infants and children during heart surgery, which usually, after an uneventful post surgical course, can be removed without complications. We report about two infants with complex congenital heart defects after cardiac surgery (arterial switch and Mustard operation for Transposition of the great arteries). Intraoperative these patients received temporary epicardial PM wires. Thirteen and 18 days post surgery, respectively, the PM wires were removed under electrocardiogram (ECG) monitoring. The patients showed acute ECG changes in terms of significant ST elevation during and after removing their pacing wires. Clinically, patients were stable and subsequent echocardiographic examination showed no evidence of myocardial dysfunction or pericardial effusion. In the course of time, patients showed no signs of arrhythmia or abnormal ECG changes. The decision to place temporary pacing wires during the cardiac surgery in patients with congenital heart defects should be considered carefully and their removal should occur under ECG monitoring as soon as the situation of the patient allows. It should be taken into consideration that a complication like this case may be related to delayed removal of temporary PM's leads.

Concussion Induced Electrocardiogram Changes

A middle aged male presented to the Emergency room with pre-syncope following a hockey induced concussion. Abnormal electrocardiogram changes combined with a strong family history resulted in a cardiac catheterization which was normal. Nearly 2 years later, flattening of the T waves persisted with symptoms. Three years later, the patient developed ALS with predominant upper motor neuron findings. doi: http://dx.doi.org/10.4021/jmc1338w

CHANGES OF ELECTROCARDIOGRAM AND CK-MB IN THE PATIENTS WITH CEREBRO-CARDIAC SYNDROME CAUSED BY ACUTE CEREBRAL INFARCTION

ObjectivesTo investigate the changes of ECG activity and CK-MB in the patients with cerebro-cardiac syndrome caused by acute cerebral infarction and to analysis the relationship between ECG, CK-MB and the...

Spontaneous coronary artery rupture in a young patient: a rare diagnosis for cardiac tamponade

We report a case of spontaneous coronary artery rupture (SCAR) in a 43-year-old male who presented with symptoms of sudden onset of chest pain and hemodynamic collapse. There were no abnormal electrocardiogram changes and serum troponin was not detected. Acute aortic dissection was suspected but urgent contrast computed tomography (CT) showed a large pericardial effusion with cardiac tamponade. This was later confirmed on trans-oesophageal echocardiogram. The SCAR was seen intra-operatively as an isolated perforation of the posterior descending artery. The patient was successfully managed with direct repair under cardiopulmonary bypass. Postoperative multi-detector dual-source 64-slice CT coronary angiography revealed normal coronary arteries with absence of atherosclerotic plaque in all coronary arterial segments. It is concluded that, though rare, a differential diagnosis of SCAR should be considered in cases of acute chest pain with cardiac tamponade in adult patients of all ages.

Electrocardiography analysis of residents in Keshan disease area in Shaanxi Province

Objective To explore the Electrocardiography (ECG) changes of residents in Keshan disease area and the status of growth and decline of Keshan disease in Shaanxi Province. Methods Using stratified randomized sampling method,2 mild,2 moderate and 2 serious disease counties were selected respectively in 2005 and 2006. A total of 6 counties were sampled,2 villages,one with severe disease and one with mild,were selected from each sampled county. A total of 12 villages were selected. The clinical examination and ECG were conducted in 3-year old children of agricultural population of the selected villages. Results ECG of 5692 cases were performed in the selected 12 village in the 6 counties,in which 4917 cases showed normal electrocardiogram,up to 86.38% (4917/5692). Two hundred and fifty-two cases showed roughly normal electrocardiograms,up to 4.43%(252/5692). Five hundred and twenty-three cases had abnormal electrocardiogram,accounting for 9.19% (523/5692). Among them,the abnormal electrocardiogram rates in mild,moderate and serious disease areas were 7.07% (144/2036), 11.41%(167/1646) and 10.54%(212/2010),respectively. Atrioventricular block was the major abnormal electrocardiogram change,followed by arrhythmia,ST-T changes,and low voltage. One hundred and thirty-nine cases were confirmed as latent and chronic Keshan diseases. One hundred and thirty-one cases were latent Keshan, and detection rate was 2.30%(131/5692). Eight cases were chronic Keshan,and the detective rate was 0.14% (8/5692). Complete right bundle branch block [37.06% (63/170) ],ST-T changes [22.35% (38/170) ],multiple premature ventricular beats [12.94% (22/170)] were the major abnormal electrocardiogram change of Keshan patients. Conclusions Atrioventricular block and arrhythmia are the major abnormal electrocardiogram changes. Keshan disease incidences are controlled under a stable condition. Key words: Keshan disease; Electrocardiography; Epidemiulogy

Cardiovascular manifestations of pheochromocytoma

Pheochromocytomas are rare tumors that originate in chromaffin tissue and produce their distant variant effects by secretion of catecholamines, tending to mislead the emergency physicians to a wrong diagnosis. Therefore, we analyze the clinical cardiovascular manifestations in patients with pheochromocytoma to improve the diagnostic ability of the emergency physicians. All patients presenting to the Chang Gung Memorial Hospital between January 1993 and December 1997 with a final diagnosis of pheochromocytoma had their charts reviewed. The data of 25 patients including age, sex, adrenergic stimulation presentations, electrocardiographic changes, location of the tumor, and complications were analyzed. Hypertension was the most important major manifestation and fluctuation of blood pressure drew our attention to the possibility of pheochromocytoma. Six patients had abnormal electrocardiographic ST-T segment changes. Five of them had chest pain which prompted them to undergo coronary angiography before surgery, because acute coronary syndrome (unstable angina and acute myocardial infarction) was suspected initially. However, all of them turned out to have normal coronary arteries. Right-sided pheochromocytoma was found in three of these five patients. We should maintain high index of suspicion for pheochromocytoma in patients presenting with chest pain, fluctuating blood pressure, and ischemic electrocardiogram (ECG) changes despite any typical isoenzyme changes. Pheochromocytoma should also be included in the differential diagnosis of acute coronary syndrome because acute catecholamine secretion may induce chest pain and abnormal ECG changes mimicking an ischemic episode. The right-sided pheochromocytoma may present more striking electrocardiographic abnormalities and clinical manifestations. (Am J Emerg Med 2000;18:622–625.