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.     

Stepwise risk stratification soon after acute myocardial infarction

A stepwise rise stratification procedure sequentially combining historical and clinical characteristics and treadmill exercise test results was applied to 702 consecutive men aged ≤70 years who were alive 21 days after acute myocardial infarction (Ml). Historical characteristics alone (prior Ml and prior angina or recurrence of pain in the coronary care unit) identified 10% of patients with the highest rate of reinfarction and death within 6 months (18%). Clinical contraindications to exercise testing identified another 40% of patients with an intermediate rate of cardiac events (6.4%). In the 50% of patients who underwent treadmill testing 3 weeks after Ml, the rate of cardiac events within 6 months was 4.4%: 3.9% in patients with a negative test and 9.7% in patients with a positive test (ischemic ST-segment depression ≥0.2 mV and a peak heart rate ≤135 beats/min). Patients with negative treadmill tests, who comprised 46% of patients ≤70 years and 53% of patients ≤60 years, had a cardiac death rate of <2% in the 6 months after Ml. The stepwise classification procedure correctly classified 72% of patients with hard medical events within 6 months. Thus, most patients who experience subsequent cardiac events are correctly classified on the basis of historical and clinical risk characteristics. In patients without these risk characteristics, early treadmill testing is useful for further discriminating high-risk from very low risk patients.     

Comparison of the predischarge exercise thallium-201 perfusion defect after myocardial infarction with myocardium at risk measured during acute infarction with technetium-99m sestamibi imaging

Background Exercise thallium-201 imaging provides a noninvasive estimate of the amount of myocardium presumed to be at risk of infarcting should a complete occlusion of the coronary stenosis occur. The relationship between the size of the exercise thallium perfusion defect and the extent of myocardium supplied by a diseased coronary artery has not been established. This study evaluates that presumed correlation. Methods Patients were injected intravenously with technetium-99m sestamibi during acute myocardial infarction before thrombolysis or conventional therapy to quantify the myocardium at risk. Twenty-six patients who underwent risk-area assessment subsequently underwent clinically driven, predischarge, submaximal exercise imaging with thallium-201. The exercise testing was performed on day 7 ± 2 days. A conventional polar map display was used to quantify the perfusion defect. Results The myocardium at risk determined by technetium-99m sestamibi at the time of infarction was 30% ± 20% of the left ventricle. The mean exercise thallium-201 defect was 34% ± 22% of the left ventricle. The exercise defect tended to be slightly larger than the myocardium at risk (4% ± 10% of the left ventricle, P = .05). There was a close correlation between the 2 measurements (r = 0.89, SE = 9.4, P < .0001). Conclusions This study shows a close correlation between the myocardium “at risk” assessed acutely by technetium-99m sestamibi and the “presumed at-risk area” determined by thallium-201 imaging on predischarge exercise testing. This finding supports the concept that the size of the exercise thallium defect caused by coronary stenosis indicates the likely size of a myocardial infarction resulting from occlusion of that stenosis. (Am Heart J 2003;145:357-63.)     

Bedside risk stratification after acute myocardial infarction: prospective evaluation of the use of heart rate and left ventricular function

OBJECTIVE: This study evaluated the predictive power of heart rate (HR) assessed from the standard 12-lead electrocardiogram (ECG) or from Holter recordings for future mortality and arrhythmic events in survivors of acute myocardial infarction (AMI). METHODS: Data from 432 consecutive survivors of AMI (343 men, 89 women; mean [SD] age, 58 [11] years) were analyzed. Heart rate was assessed from a standard 12-lead ECG and from 24-hour Holter recordings obtained at hospital discharge. In addition, left ventricular ejection fraction (LVEF) was noninvasively determined. The study end point was prospectively defined as a composite end point comprising mortality and arrhythmic events (ie, sudden death, resuscitated ventricular fibrillation, sustained ventricular tachycardia). Patients were followed for an average (SD) of 41 (25) months. RESULTS: Patient age, LVEF, and HR were univariate risk predictors of event-free survival. Multivariate analysis by means of a stepwise regression analysis revealed LVEF ( chi2 11.4, P = .0007), age ( chi 2 9.2, P = .02), and HR assessed from the standard 12-lead ECG ( chi2 7.1, P = .008) as independent risk parameters. CONCLUSIONS: Bedside risk stratification of survivors of AMI is feasible using simple parameters such as age, LVEF, and HR.     

Risk stratification after acute myocardial infarction

In recent years, the characteristics of patients who suffer acute myocardial infarction without complications during hospitalization have changed. In addition, the range of non-invasive studies available for evaluating left ventricular systolic function, residual myocardial ischemia, and myocardial viability in these patients has improved. Left ventricular systolic function and residual ischemia should be evaluated in all patients before release. The non-invasive technique used (exercise test, echocardiography, nuclear cardiology, magnetic resonance imaging) depends on availability, experience, and results at each institution. Coronary arteriography should be performed in patients with significant ischemia or severe left ventricular systolic dysfunction in non-invasive studies. In these cases coronary angiography must be performed to determine if coronary arteries are suitable for revascularization before performing a test of myocardial viability.     

Prognostic utility of predischarge dipyridamole-thallium imaging compared to predischarge submaximal exercise electrocardiography and maximal exercise thallium imaging after uncomplicated acute myocardial infarction

The prognostic value of predischarge dipyridamole-thallium scanning after uncomplicated myocardial infarction was determined by comparison with submaximal exercise electrocardiography and 6-week maximal exercise thallium imaging and by correlation with clinical events. Two endpoints were defined: cardiac events and severe ischemic potential. Of the 40 patients studied, 8 had cardiac events within 6 months (1 died, 3 had myocardial infarction and 4 had unstable angina requiring hospitalization). The finding of any redistribution on dipyridamole-thallium scanning was common (77%) in these patients and had poor specificity (29%). Redistribution outside of the infarct zone, however, had equivalent sensitivity (63%) and better specificity (75%) for events (p less than 0.05). Both predischarge dipyridamole-thallium and submaximal exercise electrocardiography identified 5 of the 8 events (p = 0.04 and 0.07, respectively). The negative predictive accuracy for events for both dipyridamole-thallium and submaximal exercise electrocardiography was 88%. In addition to the 8 patients with events, 16 other patients had severe ischemic potential (6 had coronary bypass surgery, 1 had inoperable 3-vessel disease and 9 had markedly abnormal 6-week maximal exercise tests). Predischarge dipyridamole-thallium and submaximal exercise testing also identified 8 and 7 of these 16 patients with severe ischemic potential, respectively. Six of the 8 cardiac events occurred before 6-week follow-up. A maximal exercise thallium test at 6 weeks identified 1 of the 2 additional events within 6 months correctly. Thallium redistribution after dipyridamole in coronary territories outside the infarct zone is a sensitive and specific predictor of subsequent cardiac events and identifies patients with severe ischemic potential.(ABSTRACT TRUNCATED AT 250 WORDS)     

Relationship between myocardial viability and the predischarge electrocardiographic pattern in patients with first anterior wall acute myocardial infarction

BACKGROUND: The assessment of residual viability in the infarcted area after an acute myocardial infarction is relevant to subsequent management and prognosis. OBJECTIVE: The aim of this study was to investigate the correlation between myocardial viability after an acute anterior myocardial infarction (AMI) as assessed by low dose dobutamine stress echocardiography (LDDSE) and the electrocardiographic patterns of ST segment and T wave abnormalities at the end of the first week of the acute event. METHODS: Sixty-nine consecutive patients (51 men, 18 women, mean age+/-standard deviation=57+/-11 years) who admitted to our clinic due to a first episode of transmural AMI were included in this study. Two-dimensional echocardiography was performed to all patients during rest and low dose dobutamine administration at the end of the first week of admission (7+/-2 days). Patients were classified into four groups according to ST segment and T wave morphology: group A, ST elevation < or =0.1 mV and negative T waves; group B, ST elevation < or =0.1 mV and positive T waves; group C, ST elevation > or =0.1 mV and negative T waves and group D, ST elevation > or =0.1 mV and positive T waves. RESULTS: Myocardial viability was detected more often in patients with isoelectric ST segments (22/24, 92%) than those with elevated ST segments (21/45, 47%) (P<0.001). Similarly patients with negative T waves had myocardial viability more frequently compared to those with positive T waves (32/45, 71% vs. 11/24, 46%, P<0.01). Seventeen (94%) of 18 patients in group A and 5 (83%) of six patients in group B had viable myocardium (P>0.05). Myocardial viability was found in 15 (56%) of 27 patients in group C and six (33%) of 18 patients in group D (P<0.01). As a marker of viable myocardium, isoelectricity of ST segment was specific (92%) but only moderately sensitive (51%), with a 92% positive predictive accuracy and a poor (53%) negative predictive value. T wave negativity was less specific but more sensitive than isoelectricity of ST segment for myocardial viability. CONCLUSION: The presence of isoelectric ST segment and negative T wave indicates a high probability of myocardial viability. However, absence of these electrocardiographic patterns does not exclude the presence of viable myocardium.     

Role of risk stratification after myocardial infarction

Despite advances in medical and surgical therapy for patients with heart disease, sudden cardiac death remains an important public health problem that prematurely ends the lives of more than 300,000 persons each year in North America. Many of these deaths occur in patients with a history of myocardial infarction (MI). Although severe left ventricular (LV) systolic dysfunction is used to identify patients at risk of sudden death after MI, most cardiac arrests occur in those with only mild LV dysfunction. Further, severe LV dysfunction is not a specific indicator for cardiac arrest. Risk stratification, to identify patients most likely to benefit from implantable defibrillator therapy after MI, is an essential area of investigation. Because the development of cardiac arrest is complex and likely requires the confluence of several factors, using a single test to predict the risk of sudden death or to guide implantable defibrillator therapy is unlikely to be successful. Tests that assess cardiac structure, including repolarization, and those that evaluate autonomic modulation and other factors have been developed with the goal of identifying patients at highest risk of cardiac arrest after MI. These tests, particularly in combination, appear to identify patients who may benefit from implantable defibrillator therapy after MI. Ongoing and planned randomized controlled trials will assess whether these tests can be used to guide implantable defibrillator therapy. Until the data from these studies are available, severe LV dysfunction remains the only proven approach to guide implantable defibrillator therapy after MI.     

Oxidative stress correlates with left ventricular volume after acute myocardial infarction

It has been suggested that oxidative stress may play a role in the pathophysiology of heart failure. However, little is known about the clinical relationship between oxidative stress and left ventricular dilatation after acute myocardial infarction (AMI). We prospectively studied 28 consecutive patients, successfully treated with primary coronary angioplasty, after their first AMI. To evaluate oxidative stress, plasma oxidized low-density LDL levels (U/mL) were measured serially 1 day, 7 days, 14 days, 30 days, and 90 days after the onset of AMI using a specific sandwich enzyme-linked immunosorbent assay. Left ventriculography and coronary angiography were obtained in all patients 3 months after the AMI and infarct-related arteries were all patent. Peak plasma oxidized LDL levels were seen 7 days after AMI (after 1 day: 14.7+/-1.5, 7 days: 21.0+/-2.8, 14 days: 20.2+/-2.8, 30 days: 18.3+/-2.5, 90 days: 16.5+/-2.3 U/mL). Plasma oxidized LDL levels 7 days after AMI were significantly correlated with left ventricular end-diastolic volume (115+/-7 mL; r=0.54, P=0.0025) and end-systolic volume (58+/-5 mL; r=0.49, P=0.008) 3 months after the AMI. Moreover, they were also correlated with end-diastolic volume index (68+/-4 mL/m2, r=0.40, P<0.05). However, no correlation was seen between peak plasma oxidized LDL levels and ejection fraction. These findings suggest that oxidative stress may play an important role in the development and progression of left ventricular remodeling after AMI.     

Relationship between late potentials and the predischarge electrocardiographic pattern in patients with acute anterior wall myocardial infarction

Hypothesis: The presence of late potentials on the signalaveraged electrocardiogram (SAECG) identifies patients at high risk for development of ventricular tachyarrhythmias after myocardial infarction (MI). Methods: The electrocardiogram and left ventricular function in 65 patients recovering from a first acute anterior wall MI were analyzed. We compared the pattern of the ST segment (isoelectric or elevated) and of the T wave (positive or negative) with the SAECG using an orthogonal bipolar lead configuration (X, Y, Z) with bidirectional Butterworth filtering (Simson's method). Results: Abnormal SAECG was found in 17 (26%) patients; 11 of 18 patients with ST elevation had abnormal SAECG, and only 6 of 47 patients with isoelectric ST segment developed abnormal SAECG (p<0.0001, odds ratio = 10.74). Of 19 patients with positive T waves, 10 had abnormal SAECG, and abnormal SAECG was found in 7 of 46 patients with negative T waves (p<0.003, odds ratio = 5.27). When both parameters were considered together, 9 of 12 patients with ST elevation and positive T wave developed abnormal SAECG, and 35 of 40 patients with isoelectric ST and negative T wave had normal SAECG (p<0.0002). Left ventricular ejection fraction was similar in patients with abnormal SAECG (43 ± 14%) and normal SAECG (46 ± 11 %). Conclusion: These findings suggest that patients with anterior wall MI and a predischarge pattern of ST elevation and positive T wave have a higher incidence of abnormal SAECG and therefore may have a worse prognosis, especially related to the subsequent development of ventricular arrhythmias.     

经皮冠状动脉介入治疗对急性心肌梗死后左心室重构和氧化应激反应及心功能的影响

目的探讨经皮冠状动脉介入治疗对急性心肌梗死后左心室重构、氧化应激反应及心功能的影响。方法选择2016年1~6月在我院心内科收治的169例急性心肌梗死患者,其中行经皮冠状动脉介入治疗85例(介入组)与静脉溶栓治疗84例(对照组)。观察2组在治疗后半个月及6个月肌钙蛋白Ⅰ(cTnⅠ)、N末端B型钠尿肽前体(NT-proBNP)、谷胱甘肽过氧化物酶(GSH)、超氧化物歧化酶(SOD)、LVEF及症状体征等改善情况。结果治疗后6个月,介入组NT-proBNP、LVEF、症状体征改善评分优于对照组[(227.2±52.5)ng/L vs(443.3±59.2)ng/L、(44.7±6.2)%vs(38.2±5.3)%、(5.7±1.4)分vs(10.4±2.7)分,P=0.000]。治疗后半个月,介入组cTnⅠ水平显著低于对照组[(1.15±0.29)μg/L vs(2.41±0.36)μg/L,P=0.000],2组SOD、GSH比较无显著差异(P0.05)。治疗后6个月,2组SOD、GSH均明显升高,差异有统计学意义(P=0.000)。介入组的半年再住院率为23.53%,总体有效率为94.12%,对照组再住院率高达46.43%,总体有效率仅为71.43%,2组比较有显著差异(P0.05)。结论急性心肌梗死早期接受经皮冠状动脉介入治疗,有利于降低体内氧化应激反应,逆转左心室重构,有利于心功能的恢复,提高患者的预后情况,减少再住院率。     

Risk stratification after acute myocardial infarction.

One hundred patients admitted to the hospital with acute myocardial infarction who lived 10 days and agreed to enroll were studied. Data from the history, hospital course and a 24 hour Holter electrocardiographic recording were related to cardiac mortality in the 6 months after enrollment. Fifteen cardiac deaths occurred during this period; 12 of these were sudden. The univariates with the strongest association with mortality were (in descending order): blood urea nitrogen level, serum creatinine level, serum uric acid level, enlarged heart 2 weeks after infarction, ventricular tachycardia 2 weeks after infarction, peak creatine kinase level and left ventricular failure in the coronary care unit. The odds of dying if one of these factors was present rather than absent ranged from 3.6 to 11.5. Groups with two or these univariates had up to 20 times the odds of dying in 6 months. A period of greately enhanced risk for cardiac death persists for about 6 months after acute myocardial infarction. Relatively simple clinical variables can identify the groups at highest and lowest risk. This information is useful for designing management strategies.     

Noninvasive risk stratification in women with uncomplicated acute myocardial infarction

The aim of our study was to compare the prognostic value of stress echocardiography and exercise electrocardiography after uncomplicated non-Q-wave acute myocardial infarction in a series of 89 female patients. Our data show that stress echocardiography has independent predictive value in a female patient population recovering from uncomplicated acute myocardial infarction.     

Prognostic value of predischarge 2-dimensional echocardiogram after acute myocardial infarction

The prognostic value of a 2-dimensional echocardiogram (2-D echo) was determined in 46 patients (32 men and 14 women) who survived an acute myocardial infarction (MI) from November 1979 to December 1980. The mean age of the patients was 61 years (range 36 to 92). The MI was anterior in 21, inferior in 22 and indeterminate in 3; it was transmural in 31 and nontransmural in 15. A 2-D echo was obtained 10 to 15 days after the MI--that is, 1 to 3 days before hospital discharge. A wall motion score index (WMSI) was derived with the use of a 14-segment model of the left ventricle. Each segment was assigned a number corresponding to its wall motion (0 = hyperkinetic, 1 = normal, 2 = hypokinetic, 3 = akinetic, 4 = dyskinetic and 5 = aneurysm) and the WMSI was calculated by dividing the sum of these numbers by the number of segments visualized (1.0 = normal wall motion). During a mean follow-up of 21 months (range 15 to 28), 17 patients had a complication: death, recurrence of MI, congestive heart failure of New York Heart Association class III or IV, or angina graded New York Heart Association class III or IV. Patients with compared to those without complications had a significantly higher WMSI (2.2 +/- 0.4 and 1.7 +/- 0.5, p less than 0.005). The difference in WMSI between those who died and those who survived was not significant because of the small number of deaths.(ABSTRACT TRUNCATED AT 250 WORDS)