Lack of association between prodromes nausea and vomiting, and specific electrocardiographic patterns of acute myocardial infarction

We conducted an observational study on 164 patients consecutively admitted to our coronary care unit in order to evaluate the predictive role of cardiac prodromes nausea and vomiting, in distinguishing a particular electrocardiographic pattern (Q wave versus non-Q wave and localisation) of an acute myocardial infarction. Patients with the prodromes made up 47.0% of all Q wave myocardial infarction and 59.4% in those without Q wave myocardial infarction. Furthermore, patients had nausea and vomiting in 25.0% of all Q wave myocardial infarction and in 31.2% of all non-Q wave infarction. No significant differences were found in the patients who experienced nausea and vomiting in the localisation (anterior versus inferior) of myocardial infarction. Our findings indicate that the cardiac prodromes of nausea and vomiting do not play any particular role in predicting a specific electrocardiographic pattern of acute myocardial infarction.     

Transient right axis deviation during acute anterior wall infarction or ischemia: electrocardiographic and angiographic correlation

Eleven patients, three with acute anterior myocardial infarction and eight with anterior ischemia, who developed transient right axis deviation with a left posterior hemiblock pattern during the acute phase of myocardial infarction or ischemia are described (study group). A correlation between their electrocardiographic pattern and the angiographic findings was made. The arteriographic findings were compared with those of a group of 24 patients with acute anterior myocardial infarction or ischemia without transient right axis deviation (control group). The main electrocardiographic characteristics of the right axis deviation pattern were: an average shift of the mean frontal axis to the right of 42 degrees (10 degrees to 94 degrees); increased voltage of R waves in leads II, III and a VF and appearance of small Q waves or decreased voltage of Q waves if previously present in the same leads; decreased voltage of R waves and appearance of deep S waves in lead aVL; and inverted T waves and isoelectric ST segments in leads II, III and aVF. Coronary angiography revealed that the study group had a higher incidence of significant right coronary artery obstruction and collateral circulation between the left coronary system and the posterior descending artery than did the control group (100 versus 25% and 73 versus 0%, respectively; p less than 0.01). There were no differences between the groups regarding left anterior descending and circumflex artery disease.(ABSTRACT TRUNCATED AT 250 WORDS)     

Relation between electrocardiography and coronary angiography findings in the infarct stage

One hundred and fifty-two patients underwent cardiac catheterization and coronary arteriography within 6.3 +/- 6.0 hours from onset of acute myocardial infarction. All had a standard 12-lead electrocardiogram recorded within 1.5 hours of cardiac catheterization. The electrocardiographic abnormalities present were correlated with the infarct related artery as determined by coronary arteriography. ST segment elevation was the most common finding in patients with the left anterior descending (LAD), or right coronary artery (RCA) as the infarct related artery. ST segment depression was the most common abnormality in patients with left circumflex artery (CX) as the infarct related artery. A typical pattern of anterior acute myocardial infarction was seen in 93% of all patients with the LAD as the infarct related artery. A typical pattern of acute inferior myocardial infarction was seen in 53% of all patients with RCA or CX narrowing taken as one group. The pattern of true posterior or posterolateral wall acute myocardial infarction in the absence of typical changes in the inferior leads was highly specific and predictive of CX narrowing. In contrast, the pattern of an inferior wall myocardial infarction, in the absence of true posterior or lateral wall changes, was highly specific and predictive of right coronary artery narrowing. Fifty-six percent of patients with CX artery as the infarct related artery presented with non-classical electrocardiographic abnormalities. The electrocardiographic pattern in patients with subtotal occlusions were similar to those of patients with total occlusions. Thus the electrocardiogram obtained in the first few hours of acute myocardial infarction is reliable in localizing the LAD as the infarct related artery.(ABSTRACT TRUNCATED AT 250 WORDS)     

Correlation of predischarge electrocardiographic patterns with left ventricular function in patients with anterior wall myocardial infarction

The aim of this prospective study was to assess the correlation between different predischarge electrocardiographic patterns and left ventricular function, evaluated by physical examination and echocardiography, in patients with first Q wave anterior acute myocardial infarction. A positive correlation was found between the electrocardiographic pattern and wall motion score assessed by echocardiography, reflecting a gradual worsening in left ventricular function among the different patterns. Patients with an isoelectric ST segment and negative T waves had a 73% decrease in the risk of clinical heart failure compared to those who continued to have ST elevation. Thus, a predischarge electrocardiogram can be used as a simple, noninvasive method for the risk stratification of patients with acute myocardial infarction.     

The predictive value of the electrocardiographic pattern of acute q-wave myocardial infarction for recurrent ischemia

Atotal of 140 consecutive patients with acute Q-wave myocardial infarction was evaluated to assess the relationship between different electrocardiographic patterns of evolution and the incidence of recurrent ischemia within 10 days of infarction. Patients were allocated to three groups according to the electrocardiogram at 12 h after admission: Group A: ST elevation of < 2 mm and negative T waves (75 patients); Group B: ST elevation of > 2 mm and negative T waves (35 patients); Group C: ST elevation of > 2 mm and positive T waves (30 patients). Patients in Group C had more anterior wall infarctions (82%) than Group A (40%) or Group B (58%) (p = 0.0001). Peak creatine kinase levels were lower in Group A (782 ± 115 IU) than in Groups B (1415 ± 257 IU) and C (1501 ± 287 IU) (p<0.0001). The occurrence of post-infarction recurrent ischemia was more frequent in Group A (79.2%) than in Groups B (33.3%) and C (14.8%) (p<0.0001). Patients in Group A had relatively smaller infarctions and a higher incidence of recurrent ischemia, whereas patients in Group C had larger infarctions and a lower incidence of recurrent ischemia. The electrocardiographic pattern 12 h after admission for acute myocardial infarction is helpful in identifying a subgroup at high risk of recurrent ischemia.     

Initial presenting electrocardiogram as determinant for hospital admission in patients presenting to the emergency department with chest pain: a pilot investigation

BACKGROUND: Evaluation of chest pain accounts for millions of costly Emergency Department (ED) visits and hospital admissions annually. Of these, approximately 10-20% are myocardial infarctions (MI). HYPOTHESIS: Patients with chest pain whose initial electrocardiogram (ECG) is normal do not require hospital admission for evaluation and management of a possible myocardial infarction. METHODS: The medical records of a consecutive cohort of 250 patients who presented to the ED with chest pain and were admitted by the ED physician to a cardiology inpatient service of an academic tertiary care medical center were reviewed. Reasons for admission to hospital was to rule out an acute coronary syndrome, specifically, myocardial infarction. The initial ECG of each patient was evaluated for abnormalities and compared with the final diagnosis. RESULTS: Of the 75 patients presenting with normal ECGs (normal, upright T waves and isoelectric ST segments), 1 (1.3%) was subsequently diagnosed with a myocardial infarction by Troponin I elevation alone. Of the 55 patients presenting with abnormal ECGs but no clear evidence of ischemia [i.e., left bundle branch block (LBBB), right bundle branch block (RBBB), left anterior hemiblock (LAH)], 2 (3.6%) were diagnosed with MI. Of the 48 patients presenting with abnormal ECGs questionable for ischemia (nonspecific ST and T wave changes that were not clearly ST segment elevation or depression), 7 (14.6%) were diagnosed with an MI. Of the 72 patients who presented with abnormal ECGs showing ischemia (acute ST segment elevation and/or depression), 39 (54.2%) were shown to have evidence for MI. SUMMARY: Patients who presented with normal ECGs (category 1) were extremely low risk for acute myocardial infarction. Patients with abnormal ECGs but no evidence of definite ischemia (category 2) had a relatively low incidence of MI. Patients with abnormal ECGs questionable for ischemia (category 3) had an intermediate risk of acute myocardial infarction. The majority of patients with abnormal ECGs demonstrating ischemia (category 4) were subsequently shown to evolve an acute myocardial infarction. CONCLUSIONS: Patients with chest pain and initial ECGs with ST segment abnormalities suggestive or diagnostic for ischemia, should be admitted to the hospital for further evaluation and management. Patients with ECGs that do not display acute ST segment changes are at a lower risk for acute myocardial infarction than those with acute ST segment changes and should be admitted on the basis of cardiac risk profile. (i.e., age, gender, hypertension, diabetes, smoking, known coronary artery disease, etc.) Patients with normal ECGs (category 1) are at extremely low risk, and it may be acceptable to consider further evaluation on an outpatient basis.     

Isolated U wave-inversion in acute myocardial infarction.

Three patients are presented in whom an isolated inversion of the U wave preceded by several hours typical electrocardiographic changes of an acute myocardial infarction. The association of transient hypertension and an acute U-wave inversion during this period of myocardial ischemia is discussed. It is suggested that within the appropriate clinical context an isolated U-wave inversion may portend an acute myocardial infarction.     

Simultaneous assessment of segmental and global left ventricular function by two-dimensional echocardiography in acute myocardial infarction

Both segmental and global left ventricular performance were assessed simultaneously in 29 patients with acute myocardial infarction using two-dimensional echocardiography. Comparisons were made between left ventricular wall motion versus peak CK-MB, site of infarction, and occurrence of heart failure. Two-dimensional echocardiography identified areas of dyssynergy which corresponded to electrocardiographic areas of infarction in 89% of all cases. Patients with heart failure had more dyssynergic segments, and these segments manifested more severe dyssynergy than patients without heart failure. Patients with severe global dysfunction manifested higher peak CK-MB values, and those with anterior infarction had more global dyssynergy than did those patients with inferior infarction. These observations suggest that two-dimensional echocardiography is a useful technique for localization and assessment of segmental and global dyssynergy in acute myocardial infarction. Information so derived correlates with the clinical status of patients with acute myocardial infarction, and may offer important insights into both prognosis and treatment.     

Lack of myocardial necrosis despite clinical and electrocardiographic criteria of acute transmural infarction

The development of "pathologic" Q waves with ST segment elevation is considered diagnostic of transmural myocardial infarction. Previous reports have suggested that myocardial ischemia without infarction can result in electrocardiographic abnormalities simulating those of acute infarction. However, lack of infarction has been poorly documented in these reports. If real, this phenomenon could have an impact on the management of patients with apparent acute infarction. This study describes a patient with documented severe myocardial ischemia and electrocardiographic evidence of acute transmural myocardial infarction, in whom significant myocardial necrosis has been excluded definitively.     

The giant R wave of acute myocardial infarction

The common clinical electrocardiographic criteria for diagnosis of acute transmural myocardial infarction include ST segment elevation and tall, upright T waves, but do not include changes in QRS morphology. The purpose of this study was to show that development of a 50% or greater increase in R wave amplitude, the giant R wave, in patients with acute transmural myocardial infarction occurs, and also to characterize changes in QRS morphology which may aid the ECG diagnosis of acute transmural myocardial infarction. Over the past 6 years, 36 patients with an increase in R wave amplitude during acute transmural myocardial infarction were identified at the Strong Memorial Hospital Coronary Care Unit. A significant increase in R wave height (0.33 +/- 0.10 to 0.97 +/- 0.08 mV, p less than 0.05), width (0.03 +/- 0.00 to 0.08 +/- 0.01, p less than 0.05) and area (0.01 +/- 0.00 to 0.05 +/- 0.01 mV-msec, p less than 0.05) appeared in the same ECG lead demonstrating ST segment elevation and tall T waves during the acute phase of transmural myocardial infarction. Patients with diaphragmatic myocardial infarction showed a significant (p less than 0.05) rightward QRS frontal plane axis shift and patients with anterior wall myocardial infarctions developed an anterior QRS axis shift in the horizontal plane during occurrence of the giant R wave. We conclude from this preliminary study that the giant R wave may be observed during acute transmural myocardial infarction and may in part be caused by local intramyocardial conduction delay in acutely ischemic tissue as supported by an increase in the R wave width along with shifts in the frontal and horizontal plane QRS axis toward the area of acute ischemia. The giant R wave occurs in conjunction with ST segment elevation and tall T waves and may aid the ECG diagnosis of acute transmural myocardial infarction.     

急性心肌梗死超急期J波综合征的临床特征

目的总结急性心肌梗死超急期J波综合征患者的临床特征。方法收集55例选择性冠状动脉造影诊断的急性心肌梗死超急期患者,观察其心电图的演变过程,统计分析J波综合征与冠状动脉病变以及室性心律失常发生之间的关系。结果急性心肌梗死超急期J波综合征患者16例,其中严重右冠状动脉狭窄10例,发生室性心律失常11例,急性心肌梗死超急期J波综合征患者的右冠状动脉狭窄发生率高(P<0.05),室性心律失常的发生率明显高于无J波综合征的患者(P<0.05)。结论急性心肌梗死超急期J波综合征多见于右冠状动脉受累的患者,易致室性心律失常。     

Evaluation of electrocardiographic algorithms in the assessment of the infarct-related artery in acute myocardial infarction

OBJECTIVES: In acute myocardial infarction, it is of great value to identify the infarct-related artery and the site of occlusion in a coronary artery (proximal versus distal).This study assessed the diagnostic value of two previously published electrocardiographic algorithms to identify the infarct-related artery and the site of occlusion in anterior and inferior acute myocardial infarction. METHODS AND RESULTS: We studied retrospectively a group of 88 patients with a first myocardial infarction. We determined the infarct-related artery using the electrocardiographic algorithms on the electrocardiogram at the time of admission and compared these results with the angiographically determined infarct-related artery. The best electrocardiographic algorithm could determine the infarct-related artery in an inferior myocardial infarction as the left circumflex coronary artery and as the proximal and distal right coronary artery with a sensitivity of 63%, 67% and 80%, respectively, and a specificity of 100%, 82% and 69%, respectively. One algorithm was unable to diagnose a left circumflex coronary artery occlusion. In an anterior myocardial infarction the best electrocardiographic algorithm could determine the infarct-related artery as the proximal and distal left anterior descending coronary artery with a sensitivity of 85% and 80%, respectively, and with a specificity of 77% and 82%, respectively. CONCLUSION: In acute myocardial infarction the use of electrocardiographic algorithms is helpful to predict the site of occlusion and can play a crucial role in the care of patients.     

Left anterior fascicular block: electrocardiographic criteria for its recognition in the presence of inferior myocardial infarction.

Although the vectorcardiographic criteria for recognizing left anterior fascicular block in the presence of inferior myocardial infarction are well established, comparable electrocardiographic criteria have not been studied. From vectorcardiographic criteria, it was hypothesized that in patients with left axis deviation but without bundle branch block the presence of a deep negative terminal deflection (S wave) in lead II accompanied by a positive terminal deflection (r wave) in lead aVR should indicate left anterior fascicular block whether or not inferior infarction is present. The electrocardiograms of 75 patients with unequivocal vectorcardiographic evidence of either left anterior fascicular block or inferior infarction, or both, were reviewed. Of the 47 patients who met strict vectorcardiographic criteria for left anterior fascicular block, 44 (94 percent) showed the predicted electrocardiographic pattern, including 24 of 26 (92 percent) who had both this conduction defect and inferior myocardial infarction. There was only one patient with vectorcardiographic evidence of inferior myocardial infarction alone with the findings of left axis deviation and the electrocardiographic pattern of combined infarction and fascicular block (that is, only one false positive). Thus, if bundle branch block is excluded, the proposed electrocardiographic pattern permits recognition of left anterior fascicular block whether or not there is coexistent inferior myocardial infarction.     

Clinical and arteriographic variables predictive of survival in coronary artery disease

Survival, subsequent myocardial infarction and current anginal status were determined for 90 nearly consecutive patients who underwent coronary arteriography at the Johns Hopkins Hospital between 1960 and 1967. All patients had at least one coronary arterial narrowing equal to or greater than 70 percent; 78 of 90 patients would be candidates for coronary bypass surgery by present criteria. Twenty-nine of the 78 surgically “suitable” patients died of cardiac causes; 7 of 49 survivors sustained an acute myocardial infarction (mean follow-up period 9.9 years). Patients with a 70 percent or greater narrowing proximal to the first septal branch of the left anterior descending coronary artery had a significantly greater mortality compared with patients with equivalent narrowing distal to the first septal branch or with patients without 70 percent or greater narrowing of the left anterior descending artery. The patients with a 70 percent or greater narrowing of the left anterior descending artery who died were those with a significant narrowing in at least one other major coronary artery. Multivariate stepwise discriminate function analysis of all clinical, electrocardiographic (except stress electrocardiographic) and arteriographic variables identified three independent predictors of mortality: (1) the simultaneous occurrence of a narrowing in left anterior descending and right coronary arteries, (2) prior myocardial infarction; and (3) 70 percent or greater narrowing proximal to the first anterior descending septal branch. When stress electrocardiographic findings were included, a “positive” stress electrocardiographic test was also an independent predictor of mortality.     

Submaximal exercise testing after acute myocardial infarction: myocardial scintigraphic and electrocardiographic observations.

The relation between global and regional left ventricular function and electrocardiographic signs of ischemia at rest and during submaximal supine exercise was studied in 27 patients 2 to 3 weeks after acute myocardial infarction. Dynamic myocardial scintigraphy was performed at rest and during submaximal exercise utilizing an in vivo method of labeling red blood cells with technetium-99m pertechnetate. Gated radionuclide blood pool scintigrams were obtained in a modified left anterior oblique, and in some patients also in the right anterior oblique projection, to measure left ventricular ejection fraction and segmental wall motion. Electrocardiographic monitoring of heart rate and rhythm was provided during the exercise. The submaximal exercise test was terminated when the patient's heart rate reached 125 beats/min or if angina, malignant ventricular ectopy or electrocardiographic evidence of myocardial ischemia developed before this rate was reached. The data demonstrate that patients with a recent anterior myocardial infarct, in contrast to patients with a recent inferior or nontransmural infarct, manifest a significant reduction in left ventricular ejection fraction with submaximal exercise. Of the eight patients with an anterior infarct, seven had segmental wall motion abnormalities at rest. Four of these eight manifested more severe abnormalities with submaximal exercise; three had abnormalities at rest that did not change with exercise. Four of the eight had a positive electrocardiographic response during exercise (two were taking digoxin). Of these four, only two had more marked wall motion abnormalities with effort. Of the 13 patients with an inferior infarct, 11 had apparently normal wall motion in the modified left anterior oblique projection at rest, including 2 who manifested segmental wall motion abnormalities with submaximal exercise; the 2 remaining patients had wall motion abnormalities at rest that, on exercise, became more marked in one and were unchanged in one. Four of the 13 had a positive electrocardiographic response with exercise (one was taking digoxin); only one of these had a detectably more severe wall motion abnormality with exercise. Of the six patients with a nontransmural infarct, four had no identifiable wall motion abnormalities at rest; in one of these, an abnormality developed with exercise. The remaining two patients had wall motion abnormalities at rest; in one, a positive electrocardiographic ischemic response developed with exercise. Patients with an anterior infarct appear to have a different functional ventricular response to submaximal exercise at the time of hospital discharge than patients with an inferior or nontransmural infarct. To identify ischemic responses with submaximal exercise in these patients one should ideally use both electrocardiographic monitoring and dynamic myocardial scintigraphy.     

Electrocardiographic finding simulating acute myocardial infarction in a compound metabolic aberration

A patient with hypokalemic metabolic alkalosis, hypophosphatemia, and hypomagnesemia/hypocalcemia is described. Electrocardiography demonstrated the pattern of acute anterior myocardial infarction. Further evaluation revealed that the patient had not actually had the acute myocardial infarction and that the electrocardiographic change was a mere simulation. The possible role of hypomagnesemia in the pathogenesis of the electrocardiographic change and the interrelation between the metabolic disturbances noted are discussed.     

急性心肌梗死对应导联ST段变化与冠状动脉病变的关系

目的 用冠状动脉造影技术研究急性心肌梗死(AMI)对应导联ST段变化与冠状动脉病变的关系。方法136例急性心肌梗死共分五组:①组,前壁梗死(V1-6)伴有Ⅱ,Ⅲ,aVF导联ST段下移。②组,下壁梗死(Ⅱ,Ⅲ,aVF)同时伴有V1-6导联ST段下移。③组,下壁梗死(Ⅱ,Ⅲ,aVF)同时伴有I,aVL导联ST段下移。④组,前壁梗死(V1-6)未伴有其它导联的ST段变化。⑤组,下壁梗死(Ⅱ,Ⅲ,aVF)未伴有其它导联的ST段变化。所有患者均进行冠状动脉造影。结果 前壁心肌梗死伴有Ⅱ,Ⅲ,aVF导联ST段下移25例中有88%为左冠状动脉前降支病变,其中90.9%为左冠状动脉近端病变。前壁心肌梗死未伴有Ⅱ,Ⅲ,aVF导联ST段下移的36例患者中有94.4%为左冠状动脉前降支病变,两者统计无显著性差异。在下壁心肌梗死伴有V1-6导联ST段下移组22例中有81.8%为右冠状动脉病变,但同时伴有前降支病变的却有77.3%,其中单支病变仅18.2%。下壁心肌梗死未伴有V1-6导联ST段下移34例有91.2%为右冠状动脉病变,但同时伴有前降支病变的仅有32.4%,其中单支病变达52.9%。两组统计分别为P<0.001和P相似文献   

Results of signal-averaged electrocardiography and electrophysiologic study in patients with nonsustained ventricular tachycardia after healing of acute myocardial infarction

Programmed stimulation and signal-averaged electrocardiography were performed in 43 consecutive patients with nonsustained ventricular tachycardia (VT) after healing of inferior (29 patients) or anterior wall (14 patients) acute myocardial infarction. Twenty-two patients had inducible sustained VT. Patients with inferior infarction and inducible sustained VT had significantly longer filtered QRS durations (125 +/- 19 vs 112 +/- 15 ms, p less than 0.01) and significantly lower voltage in the last 40 ms of the filtered QRS complex (19 +/- 5 vs 30 +/- 14 microV, p less than 0.05) than those without inducible sustained VT. In contrast, the signal-averaged electrocardiographic measurements in patients with anterior infarction and inducible sustained VT did not differ significantly from those without inducible sustained VT. The results of these studies were compared with those of 2 control groups: 45 patients without ventricular arrhythmias after myocardial infarction and 95 patients with spontaneous and inducible sustained VT after myocardial infarction. The signal-averaged electrocardiographic measurements in patients with spontaneous nonsustained VT after inferior infarction were intermediate between the control group without arrhythmias and the control group with sustained VT. The signal-averaged electrocardiograms in patients with nonsustained VT after anterior infarction were not significantly different from those in patients without ventricular arrhythmias. The study shows that the site of infarction influences the signal-averaged electrocardiogram in patients with VT after myocardial infarction. The signal-averaged electrocardiogram may be useful in identifying patients with nonsustained VT after a remote inferior myocardial infarction who have inducible sustained VT.     

ST-Segment elevation acute myocardial infarction due to severe hypotension and proximal left subclavian artery stenosis in a prior coronary artery bypass graft patient

Proximal subclavian artery stenosis may result in cardiac ischemia in coronary artery bypass graft patients with internal mammary grafts. We report a case of acute anterior myocardial infarction in such a patient who developed severe systemic hypotension. Symptoms and electrocardiographic changes resolved after proximal left subclavian artery stenting. Subclavian angiography should be considered in all prior coronary artery bypass graft patients with internal mammary grafts undergoing coronary angiography.     

Prediction of the site of total occlusion in the left anterior descending coronary artery using admission electrocardiogram in anterior wall acute myocardial infarction

In anterior acute myocardial infarction, ST elevation in aVL and ST depression in II, III, and aVF predict a culprit lesion in the left anterior descending artery proximal to the origin of the first diagonal branch, with good specificity and positive predictive value. Inferior ST depression is not related to remote ischemia but represents an electrocardiographic phenomenon reciprocal to ST elevation in aVL.