The differential diagnosis of acute pericarditis from the normal variant: new electrocardiographic criteria

A Case of Pure Pericarditis Associated With COVID-19: Application of Classical Clinical Evaluation for Differential Diagnosis

Pericarditis of varying severity is being recognized as a rare complication of the COVID-19 infection. We present a patient with an electrocardiogram (EKG) and physical exam findings that initially seemed to most likely be pericarditis related to the COVID-19 infection. The differential diagnosis was a bit difficult because it included ST-segment elevation myocardial infarction (STEMI) due to some EKG changes and early repolarization changes that were rather robust. Treatment options for STEMI could cause severe harm if the process turned out to be pericarditis. Treatment options for pericarditis could cause severe harm if the process turned out to be STEMI. And treatment options for early repolarization might be no treatment at all, which could cause harm if the process turned out to be STEMI or pericarditis. In this case, a correct diagnosis was very important to ensure a good clinical outcome. We would like to share our thought processes in the management of this case.

Teenager Presenting With Chest Pain and ST-Segment Changes on Electrocardiogram After SARS-CoV-2 Illness: Early Repolarization vs. Acute Pericarditis

The ST-segment elevation is commonly associated with acute myocardial Infarction. However, there are other non-ischemic causes of ST-elevation. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a highly contagious illness that continues to plague the world since the first case was reported in China over two years ago. As cases of the diseases become rampant, we have learned more of its complications which can include cardiac and pericardial disease. We present a case report of a young African American male who presented with chest pain six weeks after being diagnosed with SARS-Cov-2 pneumonia. Electrocardiogram (EKG) showed ST-segment changes that were initially presumed to be acute pericarditis. The patient was initially treated with colchicine. After further workup and a second opinion, ST-segment changes were thought to be likely benign early repolarization changes rather than pericarditis. Differential diagnosis of ST-segment changes on EKG in the patient with chest pain is broad. Subtle findings on EKG are important in distinguishing these differentials and should be well known and understood.

Electrocardiographic Changes in Children with Multisystem Inflammation Associated with COVID-19: Associated with Coronavirus Disease 2019

OBJECTIVE

To analyze findings and trends on serial electrocardiograms (ECGs) in multisystem inflammatory syndrome in children (MIS-C) associated with coronavirus disease taken during the course of illness and at follow-up.

STUDY DESIGN

We included all children presenting with MIS-C at a single center with 3 or more ECGs taken during the course of their illness. We measured ECG intervals (PR, QRSd, and QTc) and amplitudes (R-, S-, and T-waves) on each ECG and documented any arrhythmias and ST-segment changes.

RESULTS

A majority of children (n = 42, 67%) showed ECG changes. The most common findings were low QRS amplitudes and transient T-wave inversion. ST changes were uncommon and included ST-segment elevation consistent with pericarditis in 1 child and acute coronary ischemia in 1 child. Arrhythmias were seen in 13 children (21%) but were benign with the exception of 1 child who was compromised by an atrial tachycardia requiring support with extracorporeal membrane oxygenation. No children were found to have high-grade atrioventricular block.

CONCLUSIONS

MIS-C is associated with electrocardiographic changes over the course of the illness, with low amplitude ECGs on presentation, followed by transient T-wave inversion, particularly in the precordial leads. There was a low prevalence of ST-segment changes and tachyarrhythmias.

Case Report: ST-Segment Elevation in a Man With Acute Pericarditis

Background: Acute pericarditis is a rapid inflammatory condition of the pericardium with both infectious and non-infectious etiology. Most acute pericarditis is self-limited, with a small portion evolving rapidly. The definitive diagnosis of acute pericarditis often requires detailed physical examination, ECG, echocardiography, blood analysis and chest X-ray. It's usually challenging to distinguish acute pericarditis from ST-elevated myocardial infarction (STEMI) due to the similar ECG characteristics (ST segment change). Here we present a case of purulent pericarditis probably caused by esophageal perforation.

Case: A 52 year-old male presented with chest pain and dyspnea for 16 h. ST-segment elevation and positive cardiac markers lead to the initial diagnosis of ST-elevated myocardial infarction. Coronary angiography demonstrated normal coronary artery, while transthoracic echocardiography (TTE) showed massive pericardial effusion. Then, pericardiocentesis was performed with 250 ml of yellowish-green pus-like fluid extracted. A detailed history examination revealed a week history of possible esophageal perforation caused by a fishbone. And a further computed tomography (CT) demonstrated the presence of pneumomediastinum, and effusions in mediastinum, which lead to the diagnosis of purulent pericarditis. However, the patient's family refused further treatment and the patient died soon after discharge.

Conclusion: The differential diagnosis of chest pain should include acute pericarditis, which can be equally critical and fatal. And it's important to note the peculiar characteristics of acute pericarditis, which include concave and diffused ST-segment elevation, PR segment depression, and the ratio of ST-segment elevation to T wave >0.24 in lead V6. Moreover, comprehensive medical history and physical examination are crucial to the differential diagnosis of chest pain patients.

Pericarditis as a cardiac manifestation of acute leptospirosis

Leptospirosis is an infectious disease with an increasing incidence worldwide. The clinical presentation is unspecific and ranges from an asymptomatic clinical course to an acute fulminant disease. The current case report describes a 32-year-old male patient who presented with ST segment elevation in the electrocardiogram about 14 days after cross-country running. Pericarditis was diagnosed and linked to an acute leptospirosis that was serologically confirmed.

Arrhythmias in viral myocarditis and pericarditis

Acute viral myocarditis and acute pericarditis are self-limiting conditions that run a benign course and that may not involve symptoms that lead to medical assessment. However, ventricular arrhythmia is frequent in viral myocarditis. Myocarditis is thought to account for a large proportion of sudden cardiac deaths in young people without prior structural heart disease. Identification of acute myocarditis either with or without pericarditis is therefore important. However, therapeutic interventions are limited and nonspecific. Identifying those at greatest risk of a life-threatening arrhythmia is critical to reducing the mortality. This review summarizes current understanding of this challenging area in which many questions remain.

PQ segment depression in patients with short QT syndrome: a novel marker for diagnosing short QT syndrome?

BACKGROUND

Patients with short QT syndrome (SQTS) have an increased risk for atrial tachyarrhythmias, ventricular tachyarrhythmias, and/or sudden cardiac death. PQ segment depression (PQD) is related to atrial fibrillation and carries a poor prognosis in the setting of acute inferior myocardial infarction and is a well-defined electrocardiographic (ECG) marker of acute pericarditis.

OBJECTIVE

To evaluate the prevalence of PQD in SQTS and to analyze the association with atrial arrhythmias.

METHODS

Digitalized 12-lead ECGs of SQTS patients were evaluated for PQD in all leads and for QT intervals in leads II and V5. PQD was defined as ≥0.05 mV (0.5 mm) depression from the isoelectric line.

RESULTS

A total of 760 leads from 64 SQTS patients (mean age 36 ± 18 years; 48 [75%] men) were analyzed. PQD was seen in 265 (35%) leads from 52 (81%) patients and was more frequent in leads II, V3, aVF, V4, and I (n = 43 [67%], n = 30 [47%], n = 27 [42%], n = 25 [39%], and n = 25 [39%], respectively). Nine of 64 (14%) patients presented with atrial tachyarrhythmias, and all of them had PQD.

CONCLUSION

Fifty-two of 64 (81%) patients with SQTS reveal PQD. As PQD is rarely observed in healthy individuals, this ECG stigma may constitute a novel marker for SQTS in addition to a short QT interval.

ST segment elevations: always a marker of acute myocardial infarction?

Chest pain is one of the chief presenting complaints among patients attending Emergency department. The diagnosis of acute myocardial infarction may be a challenge. Various tools such as anamnesis, blood sample (with evaluation of markers of myocardial necrosis), ultrasound techniques and coronary computed tomography could be useful. However, the interpretation of electrocardiograms of these patients may be a real concern. The earliest manifestations of myocardial ischemia typically interest T waves and ST segment. Despite the high sensitivity, ST segment deviation has however poor specificity since it may be observed in many other cardiac and non-cardiac conditions. Therefore, when ST-T abnormalities are detected the physicians should take into account many other parameters (such as risk factors, symptoms and anamnesis) and all the other differential diagnoses. The aim of our review is to overview of the main conditions that may mimic a ST segment Elevation Myocardial Infarction (STEMI).

Differential diagnosis of acute pericarditis from normal variant early repolarization and left ventricular hypertrophy with early repolarization: an electrocardiographic study

BACKGROUND

Differentiation of ST-segment elevation on electrocardiogram (ECG) from acute pericarditis (AP), normal variant early repolarization (ER) and early repolarization of left ventricular hypertrophy (ERLVH) can be problematic. Hence, the authors evaluated the accuracy of the ST/T ratio in ECG to more optimally differentiate between AP, ST-segment elevation, ER and ERLVH.

METHODS

Between September 2006 and July 2010, 80 patients were enrolled in this study consisting of 25 individuals with AP, 27 with ER and 28 with ERLVH. Each ECG was analyzed in a systematic manner including the measurement of PR interval, QRS duration, QT-segment duration, PR-segment deviation, ST-segment deviation and the height of T wave. The ratio of the height of ST segment to the height of T wave was measured in leads I, II, III, aVF and V2 through V6.

RESULTS

The mean ages of the patients with AP, ER and ERLVH were 32 ± 16.5, 36 ± 15.4 and 53 ± 16 years, respectively. The ratio of the amplitude of ST segment to the amplitude of the T wave in leads I, V4, V5 and V6 proved to be a significant discriminator at a value of ≥0.25 (P < 0.05 for all).

CONCLUSIONS

Leads I, V4, V5 and V6 can all be used to differentiate AP from ER and ERLVH. When ST elevation is present in lead I, the ST/T ratio has the best predictive value (0.82) to more accurately discriminate between AP, ER and ERLVH.

Massive Pericardial Effusion in a Case of Acute Pericarditis with Slight ST-Segment Elevation of Short Duration

We present the case of a 77-year-old woman who suffered from chest pain. Her white blood cell count was 10,200/μL and C-reactive protein level was 5.5 mg/dL. There was no electrocardiogram abnormality up to 5 hours after admission. At 15 hours, slight ST-segment elevation occurred, but this disappeared on day 4. Imaging revealed slight pericardial effusion. Nonsteroidal anti-inflammatory drugs and antibiotics were administered. However, the pericardial effusion, inflammatory response, and bilateral heart failure worsened. Pericardiotomy on day 6 released 350 mL of fluid, and symptoms improved. Viral pericarditis was assumed. Massive pericardial effusion is rare in cases of acute viral pericarditis, as is slight, short-duration ST-segment elevation.

PR depression is useful in the differential diagnosis of myopericarditis and ST elevation myocardial infarction

BACKGROUND

Deviation of the PR segment is a common but often ignored ECG finding in acute myopericarditis, but seems to be rare in the acute phase of ST elevation myocardial infarction (STEMI). Since rapid bedside differential diagnosis of acute myopericarditis and STEMI is essential, we decided to assess the diagnostic power of PR depressions in patients presenting with ST elevations in the emergency room.

METHODS

Thirty-four consecutive patients with acute myopericarditis and 46 STEMI patients presenting with ST elevations fulfilling the criteria for STEMI were included. The first ECG recorded in the emergency room was analyzed with a focus on the PR segment. The diagnoses of myopericarditis and STEMI were ascertained with clinical follow-up together with rise in troponin levels, and in the STEMI patients also with coronary angiography.

RESULTS

In myopericarditis, the most common location for PR depression was lead II (55.9%), while this ECG finding least likely appeared in lead aVL (2.9%). PR depression in any lead had a high sensitivity (88.2%), but fairly low specificity (78.3%) for myopericarditis. The combination of PR depressions in both precordial and limb leads had the most favorable predictive power to differentiate myopericarditis from STEMI (positive 96.7% and negative power 90%).

CONCLUSIONS

Our present observations show that PR segment analysis is a powerful tool in the differential diagnosis of myopericarditis and STEMI. This simple information should be added to the diagnostic workup of patients presenting with ST elevations.

An unusual presentation of pulmonary embolism

Pulmonary embolism (PE) is a common cardiovascular emergency, by which occlusion of a part of the pulmonary arterial bed may lead to acute life threatening but potentially reversible right ventricular failure. Early diagnosis is fundamental to implement immediate effective treatment to reduce mortality. However, the diagnosis can be easily missed due to non-specific clinical presentation. We wish to present an unusual case whereby a patient with no risk factors for PE, symptoms suggestive of acute pericarditis and an ECG showing concave ST segment elevation was found to have multiple pulmonary emboli.

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.

Current and emerging strategies for the treatment of acute pericarditis: a systematic review

Pericarditis is a common disorder that has multiple causes and presents in various primary-care and secondary-care settings. It is diagnosed in 0.1% of all hospital admissions and in 5% of emergency room visits for chest pain. Despite the advance of new diagnostic techniques, pericarditis is most commonly idiopathic, and radiation therapy, cardiac surgery, and percutaneous procedures have become important causes. Pericarditis is frequently benign and self-limiting. Nonsteroidal anti-inflammatory agents remain the first-line treatment for uncomplicated cases. Integrated use of new imaging methods facilitates accurate detection and management of complications such as pericardial effusion or constriction. In this article, we perform a systematic review on the etiology, clinical presentation, diagnostic evaluation, and management of acute pericarditis. We summarize current evidence on contemporary and emerging treatment strategies.

Pericardial disease: diagnosis and management

Pericardial diseases can present clinically as acute pericarditis, pericardial effusion, cardiac tamponade, and constrictive pericarditis. Patients can subsequently develop chronic or recurrent pericarditis. Structural abnormalities including congenitally absent pericardium and pericardial cysts are usually asymptomatic and are uncommon. Clinicians are often faced with several diagnostic and management questions relating to the various pericardial syndromes: What are the diagnostic criteria for the vast array of pericardial diseases? Which diagnostic tools should be used? Who requires hospitalization and who can be treated as an outpatient? Which medical management strategies have the best evidence base? When should corticosteroids be used? When should surgical pericardiectomy be considered? To identify relevant literature, we searched PubMed and MEDLINE using the keywords diagnosis, treatment, management, acute pericarditis, relapsing or recurrent pericarditis, pericardial effusion, cardiac tamponade, constrictive pericarditis, and restrictive cardiomyopathy. Studies were selected on the basis of clinical relevance and the impact on clinical practice. This review represents the currently available evidence and the experiences from the pericardial clinic at our institution to help guide the clinician in answering difficult diagnostic and management questions on pericardial diseases.

Electrocardiographic manifestations of cardiac infectious-inflammatory disorders

Inflammatory disorders of the heart, although uncommon in the general population, often present initially to the emergency department. Symptoms and clinical manifestations are shared with other more common cardiopulmonary diseases, particularly acute coronary syndrome and congestive heart failure, making prompt diagnosis challenging. This review will highlight some of the clinical and electrocardiographic features that will help early diagnosis and differentiation of inflammatory cardiac disorders from other more common conditions.

Normal resting electrocardiographic variants in young athletes

With a growing awareness of the tragedy of sudden cardiac arrest (SCA) in young athletes, more extensive pre-participation examinations are being performed prior to competitive sport participation. In addition to a history and physical, young athletes often have a 12-lead resting electrocardiogram (ECG) to better identify heart disease associated with SCA. Complicating this process is that certain "abnormal" resting ECG findings are considered normal variants in healthy children and young adults. The ability to recognize these normal variants is often useful in preventing excessive referral of patients to cardiologists for evaluation of resting ECG's that are benign variations of normal and in making sound decisions regarding appropriate clearance to exercise. This review describes these normal variants.

KEYWORDS

normal variants; early repolarization; athlete's heart.

Acute myopericarditis with focal ECG findings mimicking acute myocardial infarction

BACKGROUND

Although history, physical examination, laboratory data points, and electrocardiogram (ECG) are helpful, distinguishing among pericarditis, myopericarditis, and myocardial infarction can be difficult.

OBJECTIVES

This case, which presents as pericarditis with concomitant myocarditis (myopericarditis), illustrates the four evolving ECG stages of pericarditis and highlights some of the potential difficulties in differentiating between myopericarditis and acute myocardial infarction.

CASE REPORT

We present the case of a previously healthy 15-year-old boy who presented to the Emergency Department (ED) from his family physician's office for chest pain and presumed pericarditis. The patient's initial ECG showed infero-lateral ST-segment elevation, and his troponin T was elevated at 1.54 ng/mL (ref. < 0.03). Several hours after presentation to the ED, the patient experienced "10/10" chest pain, and a repeat ECG showed ST elevation increased from the prior ECG. After an emergent echocardiogram revealed no regional wall abnormalities, he was transferred to a pediatric cardiac intensive care unit, where a heart catheterization revealed no coronary irregularities. He was discharged 4 days later with the diagnosis of myopericarditis.

CONCLUSION

This case report illustrates some of the difficulties in differentiating among myopericarditis and myocardial infarction in a 15-year-old patient presenting with chest pain.

Alarming ST-segment elevation in a young male with left anterior descending coronary artery myocardial bridging

Chest pain continues to be one of the leading emergency department presentations. Acute coronary syndrome is the most dreaded chest pain scenario, as "time is myocardium" in this situation. Numerous benign and less life-threatening diseases like early repolarization, acute pericarditis, and vasospastic angina can present with a similar clinical picture. ST-segment elevation on an electrocardiogram can occur in all these situations and in many others, creating diagnostic dilemma. A young male with chest pain and concurrent ST-segment elevation was reported. He was ultimately discovered to have myocardial bridging of a coronary arterial segment.

Acute Pericarditis

Acute pericarditis (AP) is basically a clinical diagnosis. Although specific electrocardiographic (ECG) manifestations may indeed point to its diagnosis, sole reliance on such findings in isolation of the clinical setting, however, is often the common pitfall that could lead to a misguided diagnosis. We briefly review the anatomy of the pericardium and the pathophysiology of pericarditis to highlight common signs and symptoms as well as clinical findings that may assist in the diagnosis of AP. We also feature the characteristic evolution of its ECG manifestations and point out some of its typical and atypical features to help better differentiate AP from commonly confused conditions.

ST elevation and atypical chest pain

Figure 1 illustrates the electrocardiogram (ECG) of a 42-year-old man who presented with sharp central chest pain that initially worsened with inspiration but did not appear to vary with his position. Describe the key features of the ECG and the differential diagnosis.

Chest Pain: A Clinical Assessment

Chest pain is one of the most common presentations in emergency medicine. The initial evaluation should always consider life-threatening causes such as aortic dissection, pulmonary embolism, pneumothorax, pneumomediastinum, pericarditis, and esophageal perforation. Radiographic imaging is performed in tandem with the initial clinical assessment and stabilization of the patient. Radiologic findings are key to diagnosis and management of this entity.

ST Segment and T Wave Abnormalities Not Caused by Acute Coronary Syndromes

This article reviews the ST segment and T wave abnormalities seen in non-acute coronary syndrome (ACS) electrocardiograph presentations. Particular emphasis is placed on the distinction of these non-ACS syndromes from acute coronary syndrome related ST segment and or T wave change.

Pericarditis

Pericarditis is a common disorder that has multiple causes and presents in various primary-care and secondary-care settings. New diagnostic techniques have improved the sampling and analysis of pericardial fluid and allow comprehensive characterisation of cause. Despite this advance, pericarditis is most commonly idiopathic, and radiation therapy, cardiac surgery, and percutaneous procedures have become important causes. Pericarditis is frequently self-limiting, and non-steroidal anti-inflammatory agents remain the first-line treatment for uncomplicated cases. Integrated use of new imaging methods facilitates accurate detection and management of complications such as pericardial effusion or constriction. Differentiation of constrictive pericarditis from restrictive cardiomyopathy remains a clinical challenge but is facilitated by tissue doppler and colour M-mode echocardiography. Most pericardial effusions can be safely managed with an echo-guided percutaneous approach. Pericardiectomy remains the definitive treatment for constrictive pericarditis and provides symptomatic relief in most cases. In the future, the pericardial space might become a conduit for treatments directed at the pericardium and myocardium.

Electrocardiographic manifestations: acute myopericarditis

Acute, or so-called "dry," myopericarditis occurs in the presence of diffuse inflammation of the pericardial sac and superficial epicardium from a multitude of infectious and inflammatory processes. This inflammation results in a current of myocardial injury resulting from the epicardial irritation manifested by a number of electrocardiographic findings. Classically, the electrocardiographic changes have been described as an evolution through several distinct stages involving ST segment elevation with PR segment depression, normalization of the ST segment abnormality with T wave inversion, and eventual normalization of the electrocardiogram over a period of days to several weeks. The following discussion focuses on the electrocardiographic manifestations of acute myopericarditis and includes findings useful in establishing the diagnosis as well as distinguishing the disease from other syndromes, particularly acute myocardial infarction.

Electrocardiographic manifestations: benign early repolarization

Early repolarization, also known as benign early repolarization (BER) or normal variant, is noted in approximately 1% of the population and in up to 48% of patients seen in the Emergency Department with chest pain. BER represents a benign variant of the normal electrocardiogram and is one of several syndromes producing electrocardiographic ST segment elevation (STE). The electrocardiogram (EKG) findings of BER include diffuse or widespread ST segment elevation, upward concavity of the initial portion of the ST segment, notching or slurring of the terminal QRS complex, and concordant T waves of large amplitude. This article focuses on BER and includes the electrocardiographic findings useful in making the diagnosis as well as distinguishing BER from other STE syndromes.

Early repolarization

Early repolarization (ER) is an enigma. The purpose of this review is to reemphasize the overall electrocardiographic (ECG) pattern of this normal ST variant which continues to challenge the clinician because of its similarity to the current of injury potential to myocardium or an acute pericarditis. The data were provided from the studies identified through computerized searches of Medline, Toxline, Oxford, Agricola, and Bios Afterdark, Cumulative index, and a review of bibliographies of relevant articles on the related subjects. Early repolarization has elevated, upward, concave ST segments, located commonly in precordial leads, with reciprocal depression in a VR, tall, peaked and slightly asymmetrical T waves with notch, and slur on the R wave. The other accompanying features in the ECG are vertical axis, shorter and depressed P-R interval, abrupt transition, counterclockwise rotation, presence of U waves, and sinus bradycardia. Males dominate and patients are often younger than 50 years of age. The incidence of 1 to 2% is found equally common in all races. Degree and incidence of ST elevation decrease as age advances. Exercise or isoproterenol administration may normalize the ST segment. Early repolarization is a benign condition. If the ECG conforms to a classical pattern of ER on serial ECGs, it would exclude the unnecessary hazards of present day revascularization therapy for myocardial infarction such as primary angioplasty or thrombolytic therapy, or aggressive management of acute pericarditis, and so forth. This review concludes with a discussion of comparative ECG features of ER, pericarditis, and myocardial infarction, and provides an algorithm for diagnostic management of patients suffering from these conditions.

Benign early repolarization: electrocardiographic manifestations and differentiation from other ST segment elevation syndromes

Early repolarization, also known as benign early repolarization (BER) or normal variant, is noted in approximately 1% of the population and in up to 48% of patients seen in the emergency department with chest pain. BER represents a benign variant of the normal electrocardiogram and is one of several syndromes producing electrocardiographic ST segment elevation. BER electrocardiographically includes diffuse or widespread ST segment elevation, upward concavity of the initial portion of the ST segment, notching or slurring of the terminal QRS complex, and concordant T waves of large amplitude. This article focuses on BER and includes a discussion of the electrocardiographic tools useful in making this diagnosis and in distinguishing BER from other ST segment elevation syndromes.

An electrocardiographic lead system for coronary artery bypass surgery

STUDY OBJECTIVES

To identify the optimal subset of two electrocardiographic (ECG) leads for monitoring of ischemic ST depression and elevation during coronary artery bypass grafting (CABG) surgery.

DESIGN

Prospective observational clinical study.

SETTING

University hospital cardiac surgery operating room.

PATIENTS

120 patients undergoing primary surgery or reoperation for CABG.

INTERVENTIONS

All six ECG limb leads and a precordial matrix of four leads were recorded intraoperatively approximately every 3 minutes. The limb leads were placed on the torso in modified Mason-Likar positions. The precordial leads were placed at V4, V5, and one interspace below them.

MEASUREMENTS AND MAIN RESULTS

New ischemic 1 mm ST depression and elevation episodes were determined. New ST deviation episodes attributed to nonischemic causes such as cooling at the onset of cardiopulmonary bypass (CPB), defibrillation at the end of CPB, new cardiac conduction changes after CPB, and postoperative pericarditis were excluded. Fixed ST deviation that did not change by 1 mm in the perioperative period was also excluded. Leads V5 and III constituted the best two-lead set. These leads recorded 15 of the 16 ischemic ST elevation episodes and all 8 ischemic ST depression episodes. One ST elevation episode was not recorded intraoperatively but was recorded in lead V1 in the immediate postoperative ECG. Leads V5 and II recorded 13 of the 16 ischemic ST elevation episodes and all 8 ischemic ST depression episodes. Lead V5 alone missed 8 episodes of ischemic ST elevation and one episode of ischemic ST depression.

CONCLUSIONS

For monitoring of ischemia during CABG, leads V5 and III are preferable to other two-lead sets, including the commonly used V5 and II. No single lead is adequate. Lead V5 alone missed approximately one half the episodes of ST elevation that were recorded by lead III or another inferior lead.

Myocardial ischemia after cardiopulmonary bypass

Intraoperatively, myocardial ischemia is more common after cardiopulmonary bypass (CPB) than before CPB. Ischemia associated with coronary vasospasm and thrombosis may be much more common toward the end of surgery and early in the postoperative period than previously appreciated. This may be because the coagulation system is altered during CPB, and the coronary endothelium is damaged significantly as a result of cardioplegic arrest followed by reperfusion. In this milieu, vasospasm and thrombosis may be caused by the administration of protamine. Some of the ischemia observed in this period actually is not reversible and is associated with myocardial injury and infarction. It may be ameliorated by the administration of calcium channel blockers, aspirin, and anticoagulants. Electrocardiography may be the most suitable modality for the detection of ischemia after CPB and postoperatively. During this period, many episodes of ST deviation are of a nonischemic etiology, and the ECG needs careful interpretation. Transesophageal echocardiography is suitable for use intraoperatively and early on in the intensive care unit.

Early repolarization on scalar electrocardiogram

Sixty thousand electrocardiograms were analyzed for 5 years. Six hundred (1%) revealed early repolarization (ER). Features of ER were compared with race-, age-, and sex-matched controls (93.5% were Caucasians, 77% were males, 78.3% were younger than 50 years, and only 3.5% were older than 70). Those with ER had elevated, concave, ST segments in all electrocardiograms (1-5 mv), which were located most commonly in precordial leads (73%), with reciprocal ST depression (50%) in a VR, and notch and slur on R wave (56%). Other results included sinus bradycardia in 22%, shorter and depressed PR interval in 38%, slightly asymmetrical T waves in 96.7%, and U waves in 50%. Sixty patients exercised normalized ST segment and shortened QT interval (83%). In another 60 patients, serial studies for 10 years showed disappearance of ER in 18%, and was seen intermittently in the rest of the patients. The authors conclude that in these patients with ER: 1) male preponderance was found; 2) incidence in Caucasians was as common as in blacks; 3) patients often were younger than 50 years; 4) sinus bradycardia was the most common arrhythmia; 5) the PR interval was short and depressed; 6) the T wave was slightly asymmetrical; 7) exercise normalized ST segment; 8) incidence and degree of ST elevation reduced as age advanced; 9) possible mechanisms of ER are vagotonia, sympathetic stimulation, early repolarization of sub-epicardium, and difference in monophasic action potential observed on the endocardium and epicardium.