Prognostic value of predischarge 12 lead electrocardiogram after myocardial infarction compared with other routine clinical variables

The prognostic value of QRS score (Selvester), ST depression, ST elevation, extrasystoles, P terminal force in V1, and QTc derived from the predischarge 12 lead electrocardiogram was assessed after myocardial infarction in 474 patients without intraventricular conduction defects, ventricular hypertrophy, or atrial fibrillation. The usefulness of these results in risk assessment was compared with that of other clinical data. During follow up 45 patients died. Logistic regression analysis showed that QRS score, ST depression, and QTc were independently predictive of cardiac mortality. When multivariate analysis was applied to clinical and electrocardiographic data together, however, the 12 lead electrocardiogram did not provide independent information additional to that provided by other routine clinical findings and laboratory tests such as a history of previous myocardial infarction, clinical signs of persistent heart failure, indication for digitalis or antiarrhythmic drugs at discharge, and enlarged heart on chest x ray. In conclusion, the electrocardiogram has important prognostic value; however, it is not powerful enough to further improve the risk assessment of post-infarction patients.     

Prognostic value of predischarge 12 lead electrocardiogram after myocardial infarction compared with other routine clinical variables.

The prognostic value of QRS score (Selvester), ST depression, ST elevation, extrasystoles, P terminal force in V1, and QTc derived from the predischarge 12 lead electrocardiogram was assessed after myocardial infarction in 474 patients without intraventricular conduction defects, ventricular hypertrophy, or atrial fibrillation. The usefulness of these results in risk assessment was compared with that of other clinical data. During follow up 45 patients died. Logistic regression analysis showed that QRS score, ST depression, and QTc were independently predictive of cardiac mortality. When multivariate analysis was applied to clinical and electrocardiographic data together, however, the 12 lead electrocardiogram did not provide independent information additional to that provided by other routine clinical findings and laboratory tests such as a history of previous myocardial infarction, clinical signs of persistent heart failure, indication for digitalis or antiarrhythmic drugs at discharge, and enlarged heart on chest x ray. In conclusion, the electrocardiogram has important prognostic value; however, it is not powerful enough to further improve the risk assessment of post-infarction patients.     

急性心肌梗死QRS波终端变形与其预后的关系

试探讨通过静息心电图形态的改变对急性心肌梗死 (AMI)患者的预后进行判定。将 397例AMI患者根据心电图QRS波终端变形分为两组即QRS(+)组 (即qR型导联的J点≥ 5 0 %的R波或Rs型导联的S波消失 )和QRS(- )组 ,通过冠状动脉造影结果及肌酸激酶和QRS计分法对梗死面积的估计将两组进行对比研究 ,并对其预后进行随访。结果 :QRS(+)组 89例 ,QRS(- )组 30 8例 ,QRS(+)组年龄偏大 ,前壁心肌梗死发生率较高。QRS(+)组血浆肌酸激酶峰值水平 (332 1± 2 5 77u/l)较QRS(- )组 (2 2 6 9± 32 5 1u/l)高 (P <0 .0 0 1) ,前壁心肌梗死患者QRS(+)组坏死面积 (7.3± 0 .34 )明显大于QRS(- )组 (5 .5± 0 .34 ,QRS计分法 ,P <0 .0 5 )且一年死亡率高于后者 (2 0 .5 %vs 9.8% ,P <0 .0 5 )。结论 :心电图QRS波终端变形可以作为早期判断心肌梗死病人预后的评价指标 ,对于前壁AMI的病人更有意义。     

终末QRS变形与ST段测量估测急性前壁心肌梗死面积以及溶栓疗效的临床价值

利用SelvesterQRS计分系统,比较ST段测量与QRS终末变形对急性前壁心肌梗死(简称心梗)患者最后梗死面积和溶栓治疗效果的影响。选择644例第一次急性前壁心梗患者,其中398例接受溶栓治疗,246例未接受溶栓治疗。从入院时首次稳定心电图上估计ST段抬高的导联数目、ST段抬高的幅度(∑ST)及QRS终末形态。根据QRS终末变形存在与否将患者分为两组:QRS终末变形(QRS+)组,QRS终末无变形(QRS-)组。利用修改的SelvesterQRS计分系统,从出院前心电图上估计最后梗死面积。结果:接受与未接受溶栓治疗者QRS+组∑ST、ST段抬高导联数大于QRS-组,差异有显著性(P<0.05)。在QRS-和QRS+者,溶栓治疗均能减少Selvester计分;但最后梗死面积的减少仅在QRS-的患者有意义(P<0.01)。ST段抬高的幅度与最后梗死面积之间无相关性;ST段抬高导联数仅与溶栓治疗者的最后梗死面积有关(r=0.25141,P≤0.05)。溶栓组QRS+者无复灌流率较QRS-者高。结论:QRS终末变形较ST段测量能更好地估测急性前壁心梗患者的最后梗死面积和溶栓治疗的效果。     

Terminal QRS distortion on admission is better than ST-segment measurements in predicting final infarct size and assessing the Potential effect of thrombolytic therapy in anterior wall acute myocardial infarction.

We assessed predicting final infarct size (using predischarge Selvester score) by 3 electrocardiographic variables in 267 patients with first anterior wall acute myocardial infarction (AMI) undergoing (n = 86) or not undergoing (n = 181) thrombolysis. Patients with previous AMI or inverted T waves in leads with ST elevation were excluded. The sum (sigma) of ST elevation, the number of leads with ST elevation, and the initial electrocardiographic pattern were determined on the admission electrocardiogram (absence (QRS-) or presence (QRS+) of distortion of the terminal portion of the QRS in > or =2 leads (J point > or =0.5 of the R-wave amplitude in leads I, aVL, V4 to V6, or presence of ST elevation without S waves in leads V1 to V3). There was no association between sigmaST elevation and final infarct size in patients who did or did not receive thrombolytic therapy. Analysis of covariance showed that the number of leads with ST elevation (F = 19.6), thrombolysis (F = 25.2), and QRS+ initial pattern (F = 19.5) were all associated with final infarct size (p <0.0001 for all). Among patients who did not receive thrombolytic therapy, the average Selvester score was 19.7+/-9.9 for the QRS- patients and 26.1+/-10.4 for the QRS+ patients (p = 0.02). Among patients who received thrombolytic therapy, the average Selvester score was 11.7+/-9.8 for the QRS- patients and 24.2+/-10.1 for the QRS+ patients (p <0.0001). Thrombolysis reduced final Selvester score only in the QRS- group (p <0.00001), but not in the QRS+ group (p = 0.45). It is concluded that (1) final Selvester score in anterior wall AMI can be predicted by the number of leads with ST elevation, the initial electrocardiographic pattern, and thrombolysis, and (2) thrombolysis reduces final Selvester score only in patients with QRS- pattern.     

Effects of revascularization after first acute myocardial infarction on the evolution of QRS complex changes (the DANAMI trial). DANish Trial in Acute Myocardial Infarction

The changes in QRS complex morphology associated with acute myocardial infarction (AMI) can resolve spontaneously over time. Whether complete revascularization of the infarct-related myocardial territory after AMI affects this QRS resolution has not been studied adequately. The present study compares the evolution of the changes in the QRS complex associated with AMI during 1-year follow-up in patients treated with or without revascularization after their first thrombolyzed AMI. The study is a substudy of the DANish Trial in Acute Myocardial Infarction (DANAMI) (n = 1,008) that randomized patients with inducible ischemia after their first AMI, treated with intravenous thrombolytic therapy, to conservative treatment or coronary angiography followed by the appropriate revascularization strategy. A total of 817 patients had complete sets of evaluable electrocardiograms. Electrocardiograms were obtained at randomization, and at 3, 6, and 12 months of follow-up and subjected to blinded core-laboratory evaluation according to the Selvester QRS scoring method. This score considers Q-, R-, and S-wave duration and ratios to provide a semiquantitative estimate of AMI size. The median electrocardiographic estimated infarct size in the entire population was 15% of the left ventricle at randomization. At the end of the follow-up period this estimate had decreased to 12% (p < 0.00001). There was no difference in the rate of QRS resolution whether the patients were subgrouped according to randomization or subgrouped according to actual treatment with or without revascularization. The present study confirms the findings from previous studies conducted in the prethrombolytic era, that considerable normalization of the QRS complex also occurs after AMI treated with thrombolytic therapy. This QRS normalization seems unaffected by an aggressive treatment strategy with revascularization via balloon angioplasty or bypass surgery.     

QRS记分与陈旧性心肌梗死左室功能的关系

为评价常规心电图ＱＲＳ记分与陈旧性心肌梗死者左室功能的关系，我们对５２例陈旧性心肌梗死者的ＱＲＳ记分与平衡法核素血池测得的ＬＶＥＦ，ＰＥＲ，ＰＥＲ，１／３ＥＦ，１／３ＦＲ，１／３ＥＲ，１／３ＥＦ进行相关分析，发现ＱＲＳ记分不仅与反映收缩功能的ＬＶＥＦ，ＰＥＲ，１／３ＥＦ，１／３ＥＲ明显负相关，而且与反映舒张功能的ＰＥＲ，１／３ＦＲ，１／３ＥＦ明显负相关，结果提示ＱＲＳ记分可用于估测陈旧性心肌梗死的     

Relation of QRS duration on the surface 12-lead electrocardiogram with mortality in patients with known or suspected coronary artery disease

The aim of this study was to assess the relation between QRS duration and mortality in patients with known or suspected coronary artery disease, after adjustment for myocardial functional abnormalities, as assessed by exercise echocardiography. We studied 4,033 patients (age 62 +/- 12 years; 2,360 men, 18% with previous myocardial infarction) who underwent symptom-limited exercise echocardiography. The QRS duration was electronically measured from the 12-lead electrocardiogram. The incremental value of the QRS duration for predicting mortality was assessed by adding the QRS duration at the end of each of these modeling steps: clinical data, exercise electrocardiographic, and exercise echocardiographic variables. The QRS duration correlated positively with age, the wall motion score index at rest, and percentage of ischemic segments and negatively with workload (p = 0.0001). Of the 4,033 patients, 252 died during a median follow-up of 3 years. The QRS duration was univariately associated with an increased risk of death (relative risk 8.5, 95% confidence interval CI 4.4 to 16.4, p <0.0001). In an incremental multivariate model, the clinical predictors of mortality were age, male gender, previous infarction, and diabetes mellitus (chi-square 122). Workload was incremental to clinical data in the exercise test model (chi-square 193, p <0.0001). The exercise wall motion score index was incremental to both models (chi-square 211, p <0.001). The QRS duration was associated with an incremental risk of death when added to the clinical model (chi-square 133, p = 0.009), exercise test model (chi-square = 203, p = 0.002), and echocardiographic model (chi-square = 216, p = 0.03). A QRS duration > or =105 ms best identified patients at increased risk. In conclusion, QRS duration is associated with an increased risk of death, even after adjustment for clinical factors, exercise capacity, left ventricular function, and exercise-induced myocardial ischemia.     

Value of admission electrocardiogram in predicting outcome of thrombolytic therapy in acute myocardial infarction. A randomized trial conducted by The Netherlands Interuniversity Cardiology Institute

To determine the value of the admission 12-lead electrocardiogram to predict infarct size limitation by thrombolytic therapy, data were analyzed in 488 of 533 patients with acute myocardial infarction (AMI) from a randomized multicenter study. All patients had typical electrocardiographic changes diagnostic for an AMI and were admitted within 4 hours after the onset of chest pain; 245 patients were allocated to thrombolytic treatment and 243 to conventional treatment. Cumulative 72-hour release into plasma of myocardial alpha-hydroxybutyrate dehydrogenase (HBDH) was used as a measure of infarct size. In general, the amount of infarct limitation due to thrombolytic therapy was proportional to the size of the area at risk. Patients with new Q waves, high QRS score and high ST-segment elevation or depression had the largest enzymatic infarct size in both treatment groups, irrespective of location of the AMI. Compared with conventionally treated patients, patients with anterior AMI treated with streptokinase had significant infarct size limitation (480 U/liter HBDH, 37%), and limitation was most prominent in those with Q waves (820 U/liter HBDH) or high ST elevation (750 U/liter HBDH). Infarct size limitation in inferior AMI was less impressive (330 U/liter HBDH, 33%) and patients with high ST-segment elevation (460 U/liter HBDH) or marked contralateral ST-segment depression (430 U/liter HBDH) had the most notable infarct limitation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Usefulness of the presenting electrocardiogram in predicting myocardial salvage with thrombolytic therapy in patients with a first acute myocardial infarction.

AIMS: Patients with Q waves and T-wave inversion are generally at a later stage of the infarction process than patients without these changes. Our aim was to investigate whether a single assessment of electrocardiographic parameters at presentation would predict the proportion of myocardium salvageable by thrombolytic therapy. METHODS AND RESULTS: Electrocardiographic algorithms to calculate the potential and final infarct size have been developed and allow the proportion of myocardium salvageable with therapy to be calculated. This was measured in 146 patients with acute myocardial infarction who had angiography at a median of 91 min after streptokinase. The relationship between myocardial salvage and the electrocardiographic parameters at presentation (Q waves, T-wave inversion, quantitative ST segment changes, and the initial QRS score), was examined together with the 90-min angiographic parameters (TIMI flow grade and collateral grade), clinical parameters (haemodynamics and age), and time to therapy. Parameters that correlated with myocardial salvage included the initial QRS score (r=-0.56, P<0.0001), Q wave grade (r=-0.36, P<0.0001), number of leads with ST depression (r=0.28, P<0.001), maximum ST depression (r=0.27, P<0.01), T-inversion grade (r=-0.26, P<0.01), and TIMI flow grade at 90 min (r=0.21, P<0.02). The time from symptom onset to thrombolytic therapy did not correlate with salvage (r=-0.09). On multivariate analysis, only the initial QRS score and T-inversion grade on the initial electrocardiogram were independent predictors of salvage (multivariate r using both variables combined=0.57, P<0.001). CONCLUSIONS: The QRS score and T-wave inversion grade on the presenting electrocardiogram provide important information in predicting myocardial salvage. These parameters may help triage patients to appropriate therapies.     

Body surface mapping of ectopic left ventricular activation. QRS spectrum in patients with prior myocardial infarction.

To improve electrocardiographic localization of the site of origin of ectopic left ventricular (LV) impulse formation in the heart with prior myocardial infarction, 62-lead body surface QRS integral maps were studied during LV pacing at a total of 221 endocardial sites in 14 patients with previous anterior (AMI), inferior (IMI), lateral (LMI), or anterior and inferior (AMI/IMI) myocardial infarction. The anatomic location of each pacing site was computed using digitized biplane fluoroscopic images and plotted on standardized LV endocardial polar projections. A data base of characteristic AMI and IMI mean QRS integral maps was developed after visually selecting subgroups with nearly identical QRS integral morphology from the ectopic activation sequences produced at 110 sites in eight patients with AMI and at 66 sites in four patients with IMI. Intrasubgroup pattern uniformity and intersubgroup pattern variability were statistically verified. The endocardial pacing site locations belonging to each AMI and IMI subgroup were depicted as segments on the respective LV polar projections. In patients with AMI, a total of 18 typical mean QRS integral patterns were obtained, whereas 22 different mean total QRS integral patterns showing more substantial intersubgroup variation were acquired in patients with IMI. Posterolateral regions exhibited a relatively low electrocardiographic sensitivity (six AMI and five IMI patterns) as compared with anteroseptal regions (12 AMI and 17 IMI patterns). Total QRS integral patterns obtained at 24 sites in one patient with LMI were largely compatible with the IMI mean total QRS integral patterns, whereas the majority of total QRS integral patterns acquired at 21 sites in one patient with AMI/IMI corresponded with the AMI mean total QRS integral patterns. The results show that total body surface QRS integral maps generated during LV pacing in patients with prior myocardial infarction cluster by pattern and that each QRS integral pattern is related to a circumscribed endocardial segment of ectopic impulse formation. The relation between a given QRS integral pattern and the position and size of the corresponding paced segment is dependent on infarct location. The present infarct-specific data base of characteristic total body surface QRS integral patterns provides a clinical tool to obtain detailed electrocardiographic localization of ventricular arrhythmias in patients with previous myocardial infarction.     

Plasma CK-MB activity and QRS score in estimating acute myocardial infarct size

Comparison of the peak value of plasma isoenzyme MB of creatine kinase (CK-MB) and the modified Selvester QRS score system from the standard 12-lead electrocardiogram in estimating acute myocardial infarct size and predicting hospital prognosis was performed in 52 patients with initial acute myocardial infarction (AMI). A correlation coefficient (C.C.) of 0.51 in all these patients was found. The C.C. in the patients with anterior AMI (n = 22, r = 0.64) is larger than that in inferior AMI (n = 30, r = 0.34). The prognostic value of the two methods are different. Peak CK-MB activity could predict hospital mortality and morbidity (serious arrhythmia or/and Killip AMI classification more than class III) for both anterior and inferior AMI; however, the QRS score system was significant only for anterior AMI. The clinical significance of a high ratio of peak CK-MB activity to QRS score was discussed briefly.     

Isosorbide dinitrate sublingual therapy for inferior myocardial infarction: randomized trial to assess infarct size limitation

To assess the potential of isosorbide dinitrate sublingual therapy for limiting myocardial infarct size, 41 patients with inferior acute myocardial infarction (AMI) were studied. Twenty patients were randomly assigned to the control group and 21 to the treatment group. Patients in the treatment group received 10 mg of isosorbide dinitrate every 2 hours for 72 hours. To estimate infarct size, QRS scoring, peak creatine kinase (CK) serum levels and CK curves were used. There were no significant differences between the 2 groups in maximal or cumulative activity of CK or QRS score (percent of left ventricle infarcted: 16% in the control group, 17% in the treatment group). In both groups the QRS score increased significantly by 13 hours after AMI, and the increase was highly significant by 19 to 23 hours. Thus, sublingual isosorbide dinitrate at the dosage given did not reduce infarct size in patients with inferior AMI.     

Limitations of the electrocardiogram in estimating infarction size after acute reperfusion therapy for myocardial infarction.

OBJECTIVE: To assess the ability of the 12-lead electrocardiogram to estimate infarction size after reperfusion therapy for acute myocardial infarction. DESIGN: The presence or absence of Q waves and the Selvester QRS score obtained before and after hospital discharge were compared with radionuclide estimates of infarction size and ejection fraction at discharge and 6 weeks later, regional wall motion at discharge and 6 weeks later, and myocardial perfusion defect size quantitated with Tc-99m-sestamibi at discharge. SETTING: A tertiary referral center. PATIENTS: A consecutive series of 43 patients with acute myocardial infarction who received acute reperfusion therapy and were assessed using 12-lead electrocardiography, radionuclide angiography, and Tc-99m-sestamibi tomographic imaging before discharge. INTERVENTIONS: All 43 patients received acute reperfusion therapy: 21 patients received intravenous tissue plasminogen activator, and 22 patients underwent primary percutaneous transluminal coronary angioplasty. MAIN OUTCOME MEASURE: The correlation of QRS score and Q waves with three radionuclide estimates of infarction size. RESULTS: A significant correlation was found between myocardial perfusion defect size at discharge and both left ventricular ejection fraction and regional wall motion at discharge and 6 weeks later (r = -0.71 to -0.81; all comparisons, P less than 0.001). Little correlation was found between electrocardiographic findings and radionuclide measurements of left ventricular function and perfusion. Presence or absence of Q waves at discharge was not associated with any difference in ejection fraction, regional wall motion, or perfusion defect at discharge. No correlation was found between QRS score and ejection fraction or myocardial perfusion defect size at discharge. The QRS score at discharge correlated only weakly with regional wall motion at discharge and 6 weeks later. This lack of correlation was unchanged when electrocardiograms obtained after hospital discharge were analyzed. CONCLUSION: Although inexpensive and readily available, the 12-lead electrocardiogram does not appear to provide a reliable estimate of infarction size after reperfusion therapy for acute myocardial infarction.     

Electrocardiographic comparison of myocardial salvage with primary revascularization versus thrombolysis in inferior myocardial infarction.

Primary revascularization (PR) and thrombolytic therapy (TT) reduce infarct size and mortality in patients with ST-segment elevation acute myocardial infarction (AMI). Electrocardiogram methods can determine the extent of myocardial salvage with different AMI therapies by comparing infarct size predicted by initial ST-segment changes and infarct size estimated by later quantitative QRS scores. In a community hospital setting, we used quantitative electrocardiogram methods to estimate infarct size and myocardial salvage associated with TT and PR amongst 50 patients presenting with inferior ST-segment elevation AMI. Baseline and electrocardiogram characteristics did not differ between TT (n = 29) and PR (n = 21) patients. There was no difference in median myocardial salvage (%) between TT vs. PR groups, (38.3% vs. 44.9% respectively, P =.66). Among patients with inferior AMI, myocardial salvage was achieved with both TT and PR therapy and did not differ significantly between reperfusion strategies.     

Does the electrocardiographic presence of Q waves influence the survival of patients with acute myocardial infarction?

AIMS: To compare the outcome of short- and long-term survival of patients with Q wave vs non-Q wave myocardial infarction. METHODS: A total of 6676 patients with acute myocardial infarction were enrolled on the TRAndolapril Cardiac Evaluation (TRACE) register between 1990 and 1992. Medical history, electrocardiographic diagnosis of Q wave and non-Q wave myocardial infarction, echocardiographic estimation of left ventricular systolic function determined as wall motion index, infarct complications, and survival were documented. The factors influencing the postmyocardial infarction outcome of these patients were studied after 30 days and after 8 years of follow-up, respectively. RESULTS: Cox proportional-hazard models demonstrated that the electrocardiographic Q waves had significant influence on survival during the first 30 days [risk ratio 1.4 (95% confidence limits 1.2-1.7)] but no influence thereafter [1.0 (0.9-1.1)]. The result was the same in univariate and multivariate analyses. Subgroup analysis defined by age, sex, wall motion index, presence of congestive heart failure, diabetes mellitus, arterial hypertension, subsequent myocardial infarctions and use of thrombolytic therapy did not disclose importance of Q waves on mortality. CONCLUSION: The electrocardiographic presence of Q waves is associated with increased mortality during the initial 30 days after a myocardial infarction, but has no influence thereafter.     

心肌缺血预适应在急性心肌梗死中的临床意义

目的　探讨心肌缺血预适应在 AMI中的临床意义。方法　 12 0例初发 AMI患者 ,按 AMI发作前 48小时内有无心绞痛分为缺血预适应组 (IP组 n=6 6 )与对照组 (n=5 4) ,测定左心室射血分数 (L VEF)和左心室室壁运动情况、心肌酶 (CPK、CPK- Mb)峰值、心电图 QRS记分 ,观察住院期间心律失常、心功能不全、心源性休克和室壁瘤发生率并进行比较。结果　 IP组 CPK、CPK- Mb峰值、心电图 QRS记分和心功能不全、频发室性期前收缩、VT/VF和 II- III°房室传导阻滞 (AVB)的发生率以及住院期病死率明显低于对照组 (P<0 .0 5 ) ,而 L VEF值明显高于对照组 (P<0 .0 5 )。结论　心肌缺血预适应在 AMI病人中发挥了心脏保护作用 ,有利于减少心肌梗死面积和左心室收缩功能的恢复 ,并减少恶性心律失常的发生率及住院期病死率     

Correlation between Selvester's QRS score and left ventricular function at rest and during effort in patients who survived myocardial infarction

This study was carried out in order to determine if there is any correlation between QRS score and left ventricular function at rest and during exercise after single myocardial infarction. Selvester's QRS scoring system to determine infarct size by observing Q and R standard 12-lead ECG was independently applied by three cardiologists. Left ventricular function was determined using the resting angiographic LVEF, the pulmonary wedge pressure in supine position and during exercise. The total work performed and the heart rate and systolic blood pressure percentage increase (delta) were also considered. Forty-eight male pts (mean age 52.3 +/- 8.7) were studied within 2 months after acute myocardial infarction. The site of the myocardial infarction was anterior in 13, inferior in 20, inferior plus posterior in 15. There were poor correlations between QRS score and left ventricular ejection fraction (r = -0.44) and pulmonary wedge pressure in supine position and during exercise, total work performed, delta heart rate and delta systolic blood pressure. There was no significant difference in mean QRS score between pts with abnormal (greater than 12 mmHg) and normal resting pulmonary wedge pressure in supine position (10.8 +/- 8.4 vs 7.3 +/- 5.8) or between pts with abnormal (greater than 20 mmHg) and normal exertional pulmonary wedge pressure (10.5 +/- 8.4 vs 7.4 +/- 5.7). In conclusion, the QRS score, obtained up to 30 days following an acute myocardial infarction, is not useful in determining left ventricular function at rest or during exercise.     

A simplified method to predict occurrence of complete heart block during acute myocardial infarction

Data were analyzed from 698 patients with proved acute myocardial infarction (AMI) to develop a method to predict the occurrence of complete heart block (CHB). The presence of electrocardiographic abnormalities of atrioventricular or intraventricular conduction during hospitalization was determined for each patient. The electrocardiographic risk factors considered were: first-degree atrioventricular block, Mobitz type I atrioventricular block, Mobitz type II atrioventricular block, left anterior hemiblock, left posterior hemiblock, right bundle branch block and left bundle branch block. A CHB risk score was developed that consisted of the sum of each patient's individual risk factors. CHB risk scores of 0, 1, 2 or 3 or more were associated with incidences of CHB of 1.2, 7.8, 25.0 and 36.4%, respectively. When applied to an independent AMI data base, as well as to the summed results of 6 previously reported series that identified predictors of CHB during AMI, a similar incremental risk of CHB as predicted by the risk score method was demonstrated.     

Determinants of left ventricular systolic function after acute myocardial infarction: the role of residual myocardial ischaemia

BACKGROUND: Left ventricular systolic function (LVSF) is one of the major determinants of survival after acute myocardial infarction (AMI). Some factors such as the infarct size and localization, and the patency of the infarct-related artery are known determinants of LVSF. However, the long-term effect of myocardial ischaemia on LVSF has been poorly studied in clinical settings. OBJECTIVES: To assess the acute and long-term effects of myocardial ischaemia on LVSF in patients recovering from an AMI. METHODS: A cohort of 74 patients recovering from AMI was studied. Myocardial ischaemia was detected by means of ambulatory electrocardiogram (ECG) monitoring at recruitment (4+/-2 days after AMI), exercise ECG test and stress echocardiography at discharge (7+/-4 days after AMI). LVSF was studied by means of two-dimensional echocardiography at recruitment, at discharge, and at 1, 3, 6 and 12 months after AMI. RESULTS: Patients with myocardial ischaemia on ambulatory ECG monitoring and stress echocardiography had worse LVSF at recruitment than those without ischaemia. The presence of myocardial ischaemia on ambulatory ECG monitoring was an independent determinant of LVSF at recruitment together with infarct localization and size (assessed by creatine kinase MB isoenzyme (CK-MB) levels). Patients with signs of myocardial ischaemia on ambulatory ECG monitoring and stress echocardiography had a progressive left ventricular dysfunction compared with those without ischaemia. CONCLUSIONS: Residual ischaemia is an independent determinant of LVSF after AMI and its presence implied a progressive worsening of the LVSF. Because left ventricular systolic dysfunction is a major determinant of survival after AMI, its precursors, among them residual myocardial ischaemia, should be identified. Treatment of ischaemia is known to be associated with improved prognosis and improved LVSF.