Noninvasive identification of a high risk subset of patients with acute inferior myocardial infarction

Rapid weather changes are associated with daily hospital visitors for atrial fibrillation accompanied by abnormal ECG repolarization: a case-crossover study

BACKGROUND

Atrial fibrillation (AF) is highly prevalent in the population, yet the factors contributing to AF events in susceptible individuals remain partially understood. The potential relationship between meteorological factors and AF, particularly with abnormal electrocardiograph (ECG) repolarization, has not been adequately studied. This case-crossover study aims to investigate the association between meteorological factors and daily hospital visits for AF with abnormal ECG repolarization in Shanghai, China.

METHODS

The study cohort comprised 10,325 patients with ECG-confirmed AF who sought treatment at Shanghai Sixth People's Hospital between 2015 and 2018. Meteorological and air pollutant concentration data were matched with the patient records. Using a case-crossover design, we analyzed the association between meteorological factors and the daily count of hospital visitors for AF with abnormal ECG repolarization at our AF center. Lag analysis models were applied to examine the temporal relationship between meteorological factors and AF events.

RESULTS

The analysis revealed statistically significant associations between AF occurrence and specific meteorological factors. AF events were significantly associated with average atmospheric pressure (lag 0 day, OR 0.9901, 95% CI 0.9825-0.9977, P < 0.05), average temperature (lag 1 day, OR 0.9890, 95% CI 0.9789-0.9992, P < 0.05), daily pressure range (lag 7 days, OR 1.0195, 95% CI 1.0079-1.0312, P < 0.01), and daily temperature range (lag 5 days, OR 1.0208, 95% CI 1.0087-1.0331, P < 0.01). Moreover, a significant correlation was observed between daily pressure range and daily temperature range with AF patients, particularly those with abnormal ECG repolarization, as evident in the case-crossover analysis.

CONCLUSION

This study highlights a significant correlation between meteorological factors and daily hospital visits for AF accompanied by abnormal ECG repolarization in Shanghai, China. In addition, AF patients with abnormal ECG repolarization were found to be more vulnerable to rapid daily changes in pressure and temperature compared to AF patients without such repolarization abnormalities.

ST-segment depression in left precordial leads in electrocardiogram of patients with acute inferior myocardial infarction undergoing primary percutaneous coronary intervention

BACKGROUND

The early identification of patients with acute inferior ST-segment elevation myocardial infarction (STEMI) with high risk features is particularly important. Acute inferior STEMI may be associated with ST-segment depression in the left precordial leads (V4-V6). This study assessed prognostic value of ST-segment depression in these left precordial leads during the admission of patients with acute inferior STEMI treated with primary percutaneous coronary intervention.

METHODS

This retrospective study enrolled 1,374 patients with acute inferior STEMI who underwent primary percutaneous coronary angioplasty between March 2011 and June 2014. The patients were divided into two groups: one group (n = 687) with left precordial ST-segment depression and the other (n = 687) without such ST-segment changes.

RESULTS

The patients with left precordial ST-segment depression were older and had higher incidence of hypertension, diabetes mellitus, and higher levels of troponin. In-hospital mortality was higher in patients with left precordial ST-segment depression. Advanced coronary artery disease was more observed in these patients.

CONCLUSION

In patients with acute inferior STEMI treated with primary coronary intervention, left precordial ST-segment depression during admission of ECG is associated with more advanced coronary artery disease, and worse in-hospital clinical outcomes.

Clinical Significance of Reciprocal ST-segment Changes in Patients With STEMI: A Cardiac Magnetic Resonance Imaging Study

INTRODUCTION AND OBJECTIVES

We sought to determine the association of reciprocal change in the ST-segment with myocardial injury assessed by cardiac magnetic resonance (CMR) in patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI).

METHODS

We performed CMR imaging in 244 patients who underwent primary PCI for their first STEMI; CMR was performed a median 3 days after primary PCI. The first electrocardiogram was analyzed, and patients were stratified according to the presence of reciprocal change. The primary outcome was infarct size measured by CMR. Secondary outcomes were area at risk and myocardial salvage index.

RESULTS

Patients with reciprocal change (n=133, 54.5%) had a lower incidence of anterior infarction (27.8% vs 71.2%, P < .001) and shorter symptom onset to balloon time (221.5±169.8 vs 289.7±337.3min, P=.042). Using a multiple linear regression model, we found that patients with reciprocal change had a larger area at risk (P=.002) and a greater myocardial salvage index (P=.04) than patients without reciprocal change. Consequently, myocardial infarct size was not significantly different between the 2 groups (P=.14). The rate of major adverse cardiovascular events, including all-cause death, myocardial infarction, and repeat coronary revascularization, was similar between the 2 groups after 2 years of follow-up (P=.92).

CONCLUSIONS

Reciprocal ST-segment change was associated with larger extent of ischemic myocardium at risk and more myocardial salvage but not with final infarct size or adverse clinical outcomes in STEMI patients undergoing primary PCI.

Prognostic Predictive Values of the Initial Electrocardiogram with St-Segment Elevation Acute Myocardial Infarction in Chinese Patients

Objective

To study the electrocardiogram (ECG) features that predict 30-day mortality of ST-segment elevation acute myocardial infarction (STEMI) in Chinese patients.

Method

This was a retrospective study. Patients presenting within twelve hours after the onset of chest pain with ECG features compatible with STEMI and the diagnosis confirmed after admission were included in the study. Data taken into account included age, sex and thrombolytic therapy in the emergency department. The hospital records of the patients were later retrieved from the computer. The initial ECG performed in the emergency department were reviewed.

Results

A total of 98 patients were included in the study. There was no statistically significant relationship between 30-day mortality and the type of myocardial infarction or the magnitude of the ST segment changes. Distortion of the terminal portion of the QRS complex and prior evidence of myocardial infarction (in another location different from the presenting one) showed statistically significant relationship with 30-day mortality, with odds ratio 10.364 (95% CI 1.715–62.620) and 12.731 (95% CI 2.317–69.962) respectively.

Conclusion

In newly diagnosed STEMI patients, if there is evidence of terminal distortion of the QRS complex or prior ECG changes of myocardial infarction, the 30-day mortality will be significantly higher.

Interactions Between Reciprocal ST-Segment Downsloping During ST-Elevated Myocardial Infarction and Global Cardiac Perfusion and Functional Abnormalities

Reciprocal ST-segment downsloping on electrocardiogram is a frequent finding during ST-elevated myocardial infarction (STEMI), but its etiology is still disputed. We sought to evaluate the relation between reciprocal ST-segment downsloping during STEMI and major cardiac perfusion and functional parameters. One hundred eighty-five patients with STEMI underwent emergency coronary angiography. The presence of reciprocal ST-segment downsloping was assessed. At coronary angiography, the corrected TIMI frame count (cTFC) was computed both on culprit and remote vessels and the occurrence of "no/slow reflow" phenomenon after percutaneous coronary intervention (PCI) identified. The left ventricular wall motion score index ratio (discharge/admission values) at echocardiography and the slope of high-sensitivity troponin elimination were computed as measures of effective myocardial reperfusion. Reciprocal ST-segment downsloping was revealed in 91 patients (49%). They presented higher cTFC values on remote vessels than patients without reciprocal electrocardiographic abnormalities (44 ± 18 vs 37 ± 15 cineframes × second^-1, p = 0.004). The presence of remote ST-segment downsloping was also associated with a higher prevalence of "no/slow reflow" phenomenon (59% vs 40%, p = 0.013) as well as more abnormal values of wall motion score index ratio (p = 0.042) and high-sensitivity troponin slope (p = 0.012). At multivariate analyses, a higher cTFC on remote vessels predicted the occurrence of reciprocal ST-segment changes (p = 0.018) and the development of "no/slow reflow" phenomenon after PCI (p = 0.005). In conclusion, the presence of reciprocal ST-segment downsloping during STEMI clusters with significant perfusion and cardiac functional abnormalities, predicting the development of "no reflow" phenomenon after PCI.

Prognostic value of standard electrocardiographic parameters for predicting major adverse cardiac events after acute myocardial infarction

BACKGROUND

The prognostic value of electrocardiographic (ECG) variables in predicting major adverse cardiac events (MACEs) after acute myocardial infarction (AMI) in the era of modern therapy is unclear. This study was conducted to evaluate the prognostic significance of ECG parameters in predicting 1-year MACEs for AMI patients.

METHODS

Between January 2006 and January 2008, 529 AMI patients were included. ECG variables were analyzed from the ECG taken on discharge day. The 1-year MACEs were defined as death, nonfatal MI, and revascularization including repeat percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG). Mean follow-up duration was 360 ± 119 days.

RESULTS

Of these patients, 497 (94%) patients provided complete follow-up data (355 males; 67 ± 12 years old). The rate of 1-year MACEs was 16%. In univariate analysis, heart rate, corrected QT interval, left ventricular (LV) hypertrophy, voltage (SV(1) + RV(5) ), lateral ST-depression (V(5-6) or I, aVL), pathologic Q wave (V(1-4) , V(5-6) ), ST-elevation (V(1-4) , V(5-6) or I, aVL), and T-wave inversion (V(1-4) , V(5-6) , or I, aVL) had a significant association with 1-year MACEs. In the Cox regression hazard model, lateral ST-depression (hazard ratio [HR] 2.260, 95% confidence interval [CI] 1.204 to 4.241, P = 0.011) and corrected QT interval (HR 1.007, 95% CI 1.002 to 1.011, P = 0.004) were independent predictors of 1-year MACEs. After adjustment for all risk variables, lateral ST-depression (HR 3.781, 95% CI 1.047 to 13.656, P = 0.042) was the only ECG variable that independently predicted 1-year MACEs.

CONCLUSION

Lateral ST-depression on discharge day ECG is an independent predictor of 1-year MACEs after AMI.

The utility of the standard 12-lead electrocardiogram in the prediction of proximal right coronary artery occlusion in acute inferior myocardial infarction

Prior studies have proposed several electrocardiogram criteria for identifying patients with acute inferior ST-segment elevation myocardial infarction (iSTEMI) caused by obstruction of the proximal part of the right coronary artery (RCA). We applied 11 of these criteria and three new ones to the admission electrocardiograms of 80 patients admitted with an acute iSTEMI in order to evaluate their utility. All patients received thrombolytic treatment and underwent coronary angiography during the hospitalization. Four previously described criteria (ST-segment depression in lead V1, ST-segment depression in leads V1-V3, maximum ST-segment depression in the precordial leads, and ST-segment depression in lead V3 of <or= 50% of the magnitude of ST-segment elevation in lead III) and two new used criteria (the absence of ST-segment depression in lead V1 in combination with ST-segment depression in lead V2 and the arithmetic sum of the ST-segment: III + V3 > 1) were useful in identifying patients with obstruction of the proximal part of the RCA. Among the six criteria, ST depression in V1-V3 had the highest specificity (77.2%) and positive predictive value (56.5%), and a new criterion-the arithmetic sum of the ST-elevation in V3/ST-elevation in III < 0.5--had the highest sensitivity (80.9%) and negative predictive value (86.7%). Six criteria were helpful in identifying patients with acute iSTEMI caused by obstruction of the proximal part of the RCA. One of these has not been previously reported and has the higher specificity and negative predictive value.

Electrocardiographic Diagnosis of ST-elevation Myocardial Infarction

The ECG is an essential part of the initial evaluation of patients who have chest pain, especially in the immediate decision-making process in patients who have ST-elevation myocardial infarction. This article reviews and summarizes the current information that can be obtained from the admission ECG in patients who have ST-elevation acute myocardial infarction, with an emphasis on: (1) prediction of final infarct size, (2) estimation of prognosis, and (3) the correlations between various ECG patterns and the localization of the infarct and the underlying coronary anatomy.

Acute coronary syndromes

Despite technologic advances in many diagnostic fields, the 12-lead ECG remains the basis for early identification and management of an acute coronary syndrome. This article reviews the use of the ECG in acute coronary syndromes.

The electrocardiogram in ST elevation acute myocardial infarction: correlation with coronary anatomy and prognosis

The electrocardiogram is considered an essential part of the diagnosis and initial evaluation of patients with chest pain. This review summarises the information that can be obtained from the admission electrocardiogram in patients with ST elevation acute myocardial infarction, with emphasis on: (1) prediction of infarct size, (2) estimation of prognosis, and (3) the correlations between various electrocardiographic patterns and the localisation of the infarct and the underlying coronary anatomy.

Are reciprocal changes a consequence of "ischemia at a distance" or merely a benign electrical phenomenon? A pulsed-wave tissue Doppler echocardiographic study

OBJECTIVES

The aim of the present study was to investigate whether ST segment depression in precordial leads at the time of acute inferior myocardial infarction represents a reciprocal change rather than concurrent anterior wall ischemia on the surface electrocardiography.

BACKGROUND

The mechanism of reciprocal ST segment depression during acute myocardial infarction is controversial. "Ischemia at a distance" or a benign electrical phenomenon has been implicated in numerous reports. Pulsed-wave tissue Doppler (PWTD) echocardiography can be used to examine the regional diastolic motion of the left ventricular myocardial wall and may allow the detection of ischemic segments.

METHODS

We evaluated regional myocardial ischemia using PWTD echocardiography in 48 patients with a first inferior wall myocardial infarction. The left ventricle was divided into 16 segments. PWTD echocardiographic velocities were obtained from each left ventricular segments.

RESULTS

Reciprocal ST segment depression was present in 35 patients (Group 1) but not in the remaining 13 patients (Group 2). There were no significant differences between groups 1 and 2 with respect to systolic (S) (7.4 +/- 1.1 vs 6.8 +/- 0.9 cm/s; P > 0.05), early (E) (10.5 +/- 2 vs 9.4 +/- 1.2 cm/s; P > 0.05), and late (A) (9.5 +/- 3.2 vs 8.5 +/- 2.3 cm/s; P > 0.05) diastolic waves peak velocities, E/A ratio 1.1 +/- 0.2 vs 1.1 +/- 0.1; P > 0.05), Ewave deceleration time (DT) (92 +/- 17 vs 101 +/- 16 ms; P > 0.05) and regional relaxation time (RT) (82 +/- 19 vs 93 +/- 21 ms; P > 0.05) in anterior wall (basal levels), which correspond to reciprocal ST segment depression on electrocardiography. According to E/A ratio detected by PWTD echocardiography in anterior wall and anterior septum, patients with reciprocal ST segment depression were also divided into two groups: Group A, with E/A ratio > 1; Group B, with E/A ratio < 1. Among the 35 patients with reciprocal ST segment depression, anterior wall ischemia was present in 10 patients and absent in 25 patients, whereas anterior septal ischemia was present 12 patients and absent in 23 patients.

CONCLUSIONS

Reciprocal ST segment depression during the early phases of inferior infarction is an electrical reflection of primary ST segment elevation in the area of infarction.

Usefulness of standard electrocardiographic parameters for predicting cardiac events after acute myocardial infarction during modern treatment era

Comprehensive information about the independent value of different electrocardiographic (ECG) variables in predicting cardiac events after acute myocardial infarction (AMI) in the era of modern therapy is limited. Patients (n = 1,034) underwent standard electrocardiography from 5 to 7 days after an AMI. Several time intervals and PQRST abnormalities were analyzed from the electrocardiogram. During a mean +/- SD follow-up of 752 +/- 301 days on average, 42 patients (4%) experienced cardiac death, and 259 patients (25%) a cardiac death, nonfatal AMI, or unstable angina. Several ECG variables had a significant association with cardiac events in univariate comparisons. After adjustment for all risk variables in the Cox hazards model, lateral ST-segment depression (hazard ratio [HR] 4.76, 95% confidence interval [CI] 2.40 to 9.44, p <0.0001) and atrial abnormality with a terminal deflection of the P wave > or =0.1 mV deep and > or =40 ms in duration in lead V(1) (HR 2.46, 95% CI 1.25 to 4.82, p = 0.009) were the only ECG variables that independently predicted cardiac death. Lateral ST-segment depression also predicted the combined end point of cardiac death/nonfatal AMI/unstable angina in this model (HR 1.49, 95% CI 1.14 to 1.94, p = 0.003). In conclusion, lateral ST depression and atrial abnormality on the electrocardiogram are independent predictors of cardiac death after AMI. Lateral ST depression is also associated with ischemic cardiac events.

Precordial ST-segment depression in inferior myocardial infarction is associated with slow flow in the non-culprit left anterior descending artery

BACKGROUND

Anterior precordial ST-segment depression (APSTD) is common in the setting of inferior myocardial infarction (IMI). The presence of APSTD correlates with increased risk of adverse outcomes in patients with acute IMI as well as more myocardium at risk as assessed by sestamibi, larger infarcts, lower ejection fractions, and more severe wall motion abnormalities in the infarct region. The ECG leads associated with APSTD (V1-V3) are generally thought to represent electrical activity subtended by the anterior myocardium, which is perfused by the left anterior descending artery (LAD). To determine whether APSTD is associated with abnormal blood flow in the uninvolved or non-culprit LAD, we assessed TIMI flow grades and corrected TIMI frame counts (CTFC) in both the culprit and non-culprit arteries of IMI patients.

METHODS

Data were drawn from the TIMI 10B trial of tenecteplase versus front-loaded tissue plasminogen activator in acute MI. Baseline ECGs were obtained within 12 hours of symptom onset, and angiography was performed 90 minutes following thrombolytic administration. A patient was considered to have precordial ST-segment depression if any ST-segment depression was present in any of leads V1-V3.

RESULTS

The majority of IMI's were due to right coronary artery occlusions, both in patients with APSTD (79.6%) and without APSTD (77.9%). In patients in whom the LAD was not the culprit artery but with APSTD were significantly less likely to have TIMI 3 flow at 90 minutes and more likely to have TIMI 2 flow. There was a trend toward slower CTFC in APSTD patients (27.2 +/- 13.4 vs. 22.6 +/- 8.5 frames/sec, p = 0.07).

CONCLUSIONS

Among patients with acute IMI associated with precordial ST-segment depression, flow in the non-culprit left anterior descending artery was slower than that in patients without APSTD. This finding may partially explain the occurrence of APSTD in IMI.

Clinical significance of ST-segment elevation in lead V1 in patients with acute inferior wall Q-wave myocardial infarction

BACKGROUND

This study was designed to determine the clinical significance of ST-segment elevation in the precordial leads (leads V1 and V2) in acute Q-wave inferior wall myocardial infarction.

METHODS AND RESULTS

One hundred fifty-eight consecutive patients with acute Q-wave inferior wall myocardial infarction were classified into 3 groups on the basis of the initial ST-change in V1 (group 1 = 29 patients with ST elevation, group 2 = 97 patients with ST depression, and group 3 = 32 patients with no ST-segment change). The right coronary artery was the infarct-related artery in all the patients in group 1. Although there was no significant difference between groups 1 and 2, the number of left ventricular asynergic segments was larger and the incidence of major in-hospital arrhythmias was higher in groups 1 and 2 compared with group 3. Patients in group 1 had a significantly higher incidence of proximal lesion (86%) and right ventricular infarction (69%) than the other 2 groups did. When ST elevation in leads V1 and V2 was considered, 14 of 15 patients (93%) with ST elevation only in V1 had right ventricular infarction, whereas 6 of 14 patients (43%) with ST elevation in both V1 and V2 had right ventricular infarction (P =.011).

CONCLUSIONS

ST-segment elevation in V1 on admission in patients with acute Q-wave inferior wall myocardial infarction indicates a right coronary artery lesion associated with a larger infarct size and a higher incidence of major in-hospital arrhythmias.

Value of the initial electrocardiogram in patients with inferior-wall acute myocardial infarction for prediction of multivessel coronary artery disease

BACKGROUND

Patients with inferior-wall acute myocardial infarction (AMI) who have ST-segment depression in the left precordial leads (LSTD+) on the initial electrocardiogram were reported to have more diffuse coronary artery disease (CAD) than had those without this finding (LSTD-). This suggests that LSTD+ patients may need extensive revascularization interventions more often than do LSTD- patients. However, this has not yet been confirmed.

OBJECTIVE

To compare the coronary angiographic findings and treatment strategies for patients with inferior-wall AMI according to the LSTD pattern.

METHODS

The clinical outcomes and the angiographic findings for 238 consecutive patients aged < or = 75 years who had been admitted to our hospital between 1 February 1995 and 1 February 1997 with inferior-wall AMI were retrospectively analyzed. The patients were divided into two groups according to the pattern of precordial ST-segment depression: LSTD+, ST-segment depression in leads V4-V6; and LSTD-, absence of this finding. All patients were treated according to current practice guidelines including with thrombolysis and revascularization interventions.

RESULTS

The final study population included 217 patients; 83 were LSTD+ and 134 were LSTD-. All underwent coronary angiography within 30 days of the infarction. Compared with LSTD- patients, LSTD+ patients tended to be older (mean age 62.7 +/- 11.7 versus 58.3 +/- 9.6 years, P = 0.004), and had higher incidences of hypertension (39.8 versus 24.6%, P = 0.019) previous myocardial infarction (45.8 versus 20.1%, P = 0.0001) and congestive heart failure (21.7 versus 3.7%, P = 0.00008). Three-vessel CAD was much more common, and single-vessel CAD much less common, in the LSTD+ than in LSTD- group (62.7 versus 13.4% and 8.4 versus 50.7%, P < 0.00001 for both). Coronary-artery-bypass surgery and multivessel percutaneous coronary interventions (PCI) were used in treating 65.1% of the LSTD+ versus only 6.0% of the LSTD- patients (P < 0.00001), whereas single-vessel PCI was used in treating 71.6% of the LSTD- patients versus only 24.1% of the LSTD+ patients (P < 0.00001). Thus, the LSTD- pattern predicted single-vessel disease and single-vessel PCI only, whereas the LSTD+ pattern was predictive of multivessel CAD and of use of coronary-artery-bypass surgery or multivessel PCI (predictive values of 94.0 and 65.1%, respectively).

CONCLUSIONS

Among patients with inferior-wall AMI, left precordial ST-segment depression predicts a very high prevalence of multivessel CAD and use of extensive revascularization interventions. The absence of this finding predicts nondiffuse CAD and lack of a need for extensive revascularization.

Acute myocardial infarction with isolated ST-segment elevation in posterior chest leads V7-9: "hidden" ST-segment elevations revealing acute posterior infarction

OBJECTIVES

This study was done to determine whether electrocardiographic (ECG) isolated ST-segment elevation (ST) in posterior chest leads can establish the diagnosis of acute posterior infarction in patients with ischemic chest pain and to describe the clinical and echocardiographic characteristics of these patients.

BACKGROUND

The absence of ST on the standard 12-lead ECG in many patients with acute posterior infarction hampers the early diagnosis of these infarcts and thus may result in inadequate triage and treatment. Although 4% of all acute myocardial infarction (AMI) patients reveal the presence of isolated ST in posterior chest leads, the significance of this finding has not yet been determined.

METHODS

We studied 33 consecutive patients with ischemic chest pain suggestive of AMI without ST in the standard ECG who had isolated ST in posterior chest leads V7 through V9. All patients had echocardiographic imaging within 48 h of admission, and 20 patients underwent coronary angiography.

RESULTS

Acute myocardial infarction was confirmed enzymatically in all patients and on discharge ECG pathologic Q-waves appeared in leads V7 through V9 in 75% of the patients. On echocardiography, posterior wall-motion abnormality was visible in 97% of the patients, and 69% had evidence of mitral regurgitation (MR), which was moderate or severe in one-third of the patients. Four patients (12%), all with significant MR, had heart failure, and one died from free-wall rupture. The circumflex coronary artery was the infarct related artery in all catheterized patients.

CONCLUSIONS

Isolated ST in leads V7 through V9 identify patients with acute posterior wall myocardial infarction. Early identification of those patients is important for adequate triage and treatment of patients with ischemic chest pain without ST on standard 12-lead ECG.

Influence of thrombolytic therapy on inferior acute myocardial infarction with concomitant anterior ST segment depression

The purposes of this study were to analyze the prognostic significance of precordial ST segment depression and to determine whether thrombolytic therapy is effective for all patients with inferior acute myocardial infarction (AMI) or whether there is a different effectiveness for patients with concomitant anterior ST segment depression persisting for 24 hours or longer. Medical charts of 176 patients were studied. On the basis of ECG the patients were subclassified into three groups according to the presence, persistence, or absence of significant ST segment depression: Group 1: anterior ST segment depression persisting for less than 24 hours (45.4%); Group 2: anterior ST segment depression persisting for more than 24 hours (17.6%); Group 3: no anterior ST segment depression (37%). Age, Killip class, peak creatine kinase, hospital deaths, left ventricular ejection fraction, regional wall motion score, postinfarction angina, and ventricular/supraventricular arrhythmia of all patients were studied. Parameters of the three groups were compared: worse results were found in group 1 and the worst in group 2. This result is independent of thrombolytic therapy. Finally, the same parameters of thrombolyzed and nonthrombolyzed groups were compared: no statistically significant difference was observed. Among thrombolyzed patients the number of those with ST depression lasting more than 24 hours is lower than in nonthrombolyzed patients. It can be assumed that thrombolytic therapy in inferior AMI determines a shifting of patients from a worse prognosis group (ST segment depression persisting for more than 24 hours) to a better prognosis group (ST segment depression persisting for less than 24 hours).

Correlation of angiographic findings and right (V1 to V3) versus left (V4 to V6) precordial ST-segment depression in inferior wall acute myocardial infarction

This study assessed whether differences in the underlying mechanisms for various patterns of precordial ST-segment depression with inferior acute myocardial infarction (AMI) are associated with poorer prognoses. We studied 1,155 patients with inferior AMI who underwent thrombolysis in the Global Utilization of Streptokinase and TPA for Occluded arteries (GUSTO-I) angiographic substudy: those without precordial ST depression (n = 412; 35.7%), those with maximum ST depression in leads V1 to V3 (n = 547; 47.4%), and those with maximum ST depression in leads V4 to V6 (n = 196; 17.0%) on admission electrocardiogram. We compared the infarct-related artery, presence of left anterior descending or multivessel coronary artery disease, and left ventricular function among groups. Patients with maximum ST depression in leads V4 to V6 more often had 3-vessel disease (26.0%) than those without precordial ST depression (13.5%) or those with ST depression in leads V1 to V3 (15.7%; p = 0.002), and they had a lower ejection fraction (median 54% vs 60% and 55%, respectively; p <0.001). Patients with maximum ST depression in leads V1 to V3 less often had AMIs due to proximal right coronary artery obstruction (23.9%) than patients without precordial ST depression (35.2%) or those with ST depression in leads V4 to V6 (40.0%; p = 0.001) and had larger AMIs as estimated by peak creatine kinase. Different patterns of precordial ST depression are associated with distinctive coronary anatomy. ST depression in leads V4 to V6, but not V1 to V3, confers a greater likelihood of multivessel coronary artery disease.

Significance of ST segment elevations in posterior chest leads (V7 to V9) in patients with acute inferior myocardial infarction: application for thrombolytic therapy

OBJECTIVES

This study was designed to examine whether ST segment elevation in posterior chest leads (V7 to V9) during acute inferior myocardial infarction (MI) identifies patients with a concomitant posterior infarction and whether these patients might benefit more from thrombolysis.

BACKGROUND

Because the posterior wall is faced by none of the 12 standard electrocardiographic (ECG) leads, the ECG diagnosis of posterior infarction is problematic and has often remained undiagnosed, especially in the acute phase.

METHODS

Eighty-seven patients with a first inferior infarction who were treated with recombinant tissue-type plasminogen activator were stratified according to the presence (Group A [46 patients]) or absence (Group B [41 patients]) of concomitant ST segment elevation in posterior chest leads V7 to V9.

RESULTS

Patients in Group A had a higher incidence of posterolateral wall motion abnormalities (p < 0.001) on radionuclide ventriculography, a larger infarct area (as evidenced by higher peak creatine kinase levels) (p < 0.02) and a lower left ventricular ejection fraction (LVEF) at hospital discharge (p < 0.008) than those in Group B. ST segment elevation in leads V7 to V9 was associated with a higher incidence of at least one of the following adverse clinical events: reinfarction, heart failure or death (p = 0.05). Although patency of the infarct-related artery (IRA) in Group A resulted in an improved LVEF at discharge (p < 0.012), LVEF was unchanged in Group B, regardless of the patency status of the IRA.

CONCLUSIONS

ST segment elevation in leads V7 to V9 identifies patients with a larger inferior MI because of concomitant posterolateral involvement. Such patients might benefit more from thrombolytic therapy.

Association between anterior ST depression and increased myocardial salvage following reperfusion therapy in patients with inferior myocardial infarction

PURPOSE

To determine electrocardiographic features associated with myocardial salvage following reperfusion therapy in patients with inferior myocardial infarction.

PATIENTS AND METHODS

Ninety-two consecutive patients with acute inferior myocardial infarction were treated with reperfusion therapy in a tertiary care center. Several features were measured on the presenting electrocardiogram, including the presence or absence of ST depression in the chest leads and the total magnitudes of ST elevation or depression, and were then evaluated for their association with myocardial salvage. Myocardial salvage (% of left ventricle) was the difference between myocardium at risk and final infarct size. Tomographic myocardial perfusion imaging with technetium-99m sestamibi was performed acutely to measure myocardium at risk and repeated prior to hospital discharge to measure final infarct size.

RESULTS

The amount of myocardium at risk of infarction in the 92 patients was 19.1%+/-11.3% (range 1% to 68%), and the final infarct size was 10.6%+/-10.0% (range 0% to 45%). Thus, myocardial salvage in the 92 patients was 8.5%+/-8.4% (range -11% to 35%) of the left ventricle, or 0.51+/-0.38 (range 0.0 to 1.0) when expressed as a fraction of the myocardium at risk (salvage index). The presence or absence of anterior ST depression was the only one of seven electrocardiographic variables that was associated with myocardial salvage. Myocardial salvage was significantly greater in patients with anterior ST depression compared with those without it (10.6%+/-9.0% versus 5.9%+/-6.7%, P=0.025). Myocardium at risk was significantly greater in patients with anterior ST depression compared with those without the depression (22.8%+/-12.2% versus 14.6%+/-8.3%, P=0.0006), and infarct size tended to be larger (12.1%+/-10.4% versus 8.7%+/-9.4%, P=0.10). Myocardial salvage as a fraction of the myocardium at risk (salvage index) was similar between the two patient groups (0.52+/-0.37 versus 0.50+/-0.39, P=NS).

CONCLUSION

The presence of anterior ST depression during inferior myocardial infarction identifies a group of patients with the potential for greater myocardial salvage with reperfusion therapy. Such patients derive greater absolute benefit from reperfusion therapy because they have a larger amount of myocardium at risk, although their response to therapy (salvage index) is not intrinsically different.

Comparative prognostic significance of simultaneous versus independent resolution of ST segment depression relative to ST segment elevation during acute myocardial infarction

OBJECTIVES

We sought to determine the prognostic significance of simultaneous versus independent resolution of ST segment depression that occurs concomitant with ST segment elevation during acute myocardial infarction (AMI).

BACKGROUND

ST segment depression in leads other than those showing ST segment elevation during AMI is a common phenomenon. Whether this indicates adverse outcomes remains controversial. We hypothesized that the timing of ST segment depression resolution relative to ST segment elevation resolution might differentiate between a high risk group and a low risk group of patients.

METHODS

Continuous 12-lead ST segment monitoring was performed after thrombolytic therapy for AMI in 413 patients, 261 of whom met technical criteria for analysis. Blinded analysis of ST segment depression resolution patterns was used to group patients as follows: 1) no ST segment depression at any time (control group); 2) ST segment depression resolving simultaneously with ST segment elevation (simultaneous group); and 3) ST segment depression persisting after ST segment elevation resolution (independent group). These patterns were correlated with the outcomes-recurrent angina, reinfarction, heart failure and death-using chi-square analysis and the Fisher exact test for categoric variables and the Wilcoxon rank-sum test for continuous variables.

RESULTS

The incidence of recurrent angina, reinfarction and heart failure was similar among the three groups. In-hospital mortality, however, was significantly higher in the independent group (13%) than either the simultaneous group (1%, p < 0.001) or the control group (0%, p = 0.002).

CONCLUSIONS

Continuous analysis of ST segment resolution identifies, among patients with AMI with concomitantly occurring ST segment elevation and depression, a subgroup with increased in-hospital mortality. The pathogenic mechanism of increased mortality is not currently known.

Revisiting reperfusion therapy in inferior myocardial infarction

Although thrombolytic therapy for acute myocardial infarction (MI) is recommended without regard for infarct location, treatment results are less impressive for inferior than for anterior MI because the amount of myocardium at risk is smaller and less strategically located, and the mortality risk is lower. Whereas the risks associated with anterior MI are relatively constant, high risk subsets of patients with an inferior MI can be identified by simple electrocardiographic criteria, including left precordial ST segment depression, complete atrioventricular heart block and right precordial ST segment elevation. Unfortunately, none of the placebo-controlled, randomized trials have analyzed the benefit of thrombolytic therapy for inferior MI in high risk versus low risk subsets. Thrombolytic therapy should be more successful in reducing infarct size and decreasing mortality in high risk patients with an inferior MI. Thrombolytic therapy may not decrease hospital mortality in low risk patients (baseline risk 2% to 4%) or those with symptom duration > 6 h. Whereas it is arguable whether coronary angioplasty is superior to thrombolytic therapy in anterior MI, there are no mortality data to support using angioplasty as a primary or rescue reperfusion strategy instead of thrombolytic therapy in inferior MI, unless thrombolytic contraindications are present or the patient is in cardiogenic shock.

Usefulness of ST-segment depression in non-infarct-related electrocardiographic leads in predicting prognosis after thrombolytic therapy for acute myocardial infarction

This study investigated both the in-hospital and long-term prognostic significance of ST-segment depression in non-infarct-related leads in patients who received thrombolytic therapy after acute myocardial infarction (AMI). We evaluated 221 consecutive patients who were admitted with their first AMI and underwent thrombolysis. Patients were followed for an average of 31 months and were classified into 3 groups: group 1 included 51 patients with persistent ST-segment depression, group 2 had 97 patients with transient ST-segment depression, and group 3 consisted of 73 patients without ST-segment depression (absent). Group 1 had significantly worse long-term survival during follow up by Kaplan-Meier analysis (55%) versus group 2 (81%) and group 3 (94%) (p = 0.0004) and higher event rates. This prognostic significance seemed to be maintained in both the anterior and inferior wall AMI groups. Multivariate analysis, using the Cox model, showed that Killip class, in-hospital left ventricular ejection fraction, and the persistence of ST-segment depression on the predischarge electrocardiogram (group 1) were independent predictors of survival. ST-segment depression in non-infarct-related leads on the predischarge electrocardiogram is an independent risk factor for worse long-term survival after anterior as well as inferior AMI treated with thrombolytic therapy.

Prognostic significance of precordial ST-segment changes in acute inferior wall myocardial infarction

STUDY OBJECTIVE

To examine the clinical significance of precordial ST-segment changes in patients with acute Q-wave inferior wall myocardial infarction.

DESIGN

Prospective evaluation (clinical follow-up) of Q-wave inferior wall myocardial infarction over a 6-year period in patients who fulfilled the inclusion criteria.

SETTING

Coronary care unit at a university hospital.

PATIENTS

Two hundred consecutive patients with acute Q-wave inferior wall myocardial infarction admitted to the coronary care unit within 24 h from the onset of chest pain.

MEASUREMENTS AND RESULTS

Precordial ST-segment depression resolved <24 h (transient) after admission in 84 patients, lasted > or = 24 h (persistent) in 48 patients, and was absent in 68 patients, while ST-segment elevation in V4R was detected in 60 patients. Seventy-one patients had major in-hospital complications and 18 patients died in the hospital. When nine variables were used in the multivariate analysis, right ventricular dilatation and persistent precordial ST-segment depression were the important factors related to major in-hospital complications, whereas age, alveolar arterial oxygen difference, and persistent precordial ST-segment depression were important for in-hospital deaths.

CONCLUSION

Left ventricular posterior wall involvement, diagnosed by persistent precordial ST-depression, was an independent and stronger predictor of major in-hospital complications and deaths than right ventricular involvement in patients with acute Q-wave inferior wall myocardial infarction.

Maximal precordial ST-segment depression in leads V4-V6 in patients with inferior wall acute myocardial infarction indicates coronary artery disease involving the left anterior descending coronary artery system

BACKGROUND

In inferior wall acute myocardial infarction, maximal ST-segment depression in left precordial leads (V4-V6) has been shown to be associated with increased in-hospital mortality, presumably due to coronary artery disease involving the left anterior descending coronary artery system.

METHODS

We measured ST-segment deviation from baseline in the initial electrocardiogram of patients with inferior wall acute myocardial infarction, who subsequently underwent coronary angiography during their in-hospital stay. Patients were divided into three groups: (I) No precordial ST-segment depression (n = 34). (II) Maximal precordial ST-segment depression in leads V1-V3 (n = 44). (III) Maximal precordial ST-segment depression in leads V4-V6 (n = 14).

RESULTS

The left anterior descending coronary artery or its diagonal branch were stenosed (> 50%) in 32%, 41%, and 71% of patients in groups I, II, and III, respectively (p = 0.04), and severely stenosed (> 70%) in 18%, 18% and 57% of patients in the respective groups (p = 0.007).

CONCLUSION

In patients with inferior wall acute myocardial infarction, maximal precordial ST-segment depression in leads V4-V6 is suggestive of severe coronary artery disease involving the left anterior descending coronary artery or its diagonal branch.

Prognostic significance of precordial ST segment depression on admission electrocardiogram in patients with inferior wall myocardial infarction

OBJECTIVES

This study assessed retrospectively the correlation between the pattern of precordial ST segment depression on the admission electrocardiogram (ECG) and hospital mortality in patients with an inferior myocardial infarction treated with intravenous thrombolytic therapy.

BACKGROUND

Previous studies have shown that in acute inferior myocardial infarction, ST segment depression in the precordial leads is associated with increased hospital mortality. However, the significance of the different patterns of precordial ST segment depression has been evaluated in only two previous studies.

METHODS

The study included 1,321 patients (1,020 men) who enrolled in the Global Utilization of Streptokinase and t-PA for Occluded Coronary Arteries (GUSTO-I) trial in Israel and received intravenous thrombolytic therapy. Patients with an ST segment elevation > or = 0.1 mV in at least two of the inferior leads were included. Patients were classified into four groups on the basis of their admission ECG: group I = patients with no precordial ST segment depression (n = 346); group II = those for whom the sum of ST segment depression in leads V1 to V3 was greater than that in leads V4 to V6 (n = 700); group III = those for whom the sum of ST depression in leads V1 to V3 was equal to that in leads V4 to V6 (n = 162); group IV = those with maximal ST depression in leads V4 to V6 (n = 113).

RESULTS

The overall hospital mortality rate was 3.6% (48 patients): for groups I, II, III and IV it was 2.9%, 2.8%, 4.3% and 9.7%, respectively. Multivariable logistic regression analysis confirmed that hospital mortality was independently associated with the pattern of precordial ST segment depression. The odd ratios in group IV relative to group I was 2.78 (95% confidence interval 1.26 to 6.13, p = 0.007).

CONCLUSIONS

The risk of mortality is higher in patients with an inferior myocardial infarction and maximal ST segment depression in precordial leads V4 to V6 versus precordial leads V1 to V3 on the admission ECG.

Prognostic significance of precordial ST segment depression during inferior myocardial infarction in the thrombolytic era: results in 16,521 patients

OBJECTIVES

We examined the prognostic significance of precordial ST segment depression among patients with an acute inferior myocardial infarction.

BACKGROUND

Although precordial ST segment depression has been associated with a poor prognosis, this correlation has not been adequately quantified, partly because of small sample sizes and methodologic limitations in previous studies.

METHODS

We examined the clinical and angiographic outcomes of 16,521 patients with an acute inferior myocardial infarction who underwent thrombolysis in the Global Utilization of Streptokinase and t-PA for Occluded Coronary Arteries (GUSTO-I) study. Patients were classified into those without precordial ST segment depression (n = 6,422 [38.9%]), those with ST segment depression in leads V1 to V3 only (n = 5,850 [35.4%]), those with ST segment depression in leads V4 to V6 only (n = 876 [5.3%]) and those with ST segment depression in both leads V1 to V3 and leads V4 to V6 (n = 3,373 [20.4%]) on initial electrocardiography. Outcome measures included postinfarction complications (second- or third-degree heart block, congestive heart failure or shock) and 30-day and 1-year mortality.

RESULTS

Patients with precordial ST segment depression had larger infarctions, more postinfarction complications and a higher mortality rate than those without precordial ST segment depression (4.7% vs. 3.2% at 30 days; 5.0% vs. 3.4% at 1 year; both p < 0.001), regardless of whether ST segment depression was noted in leads V1 to V6 or in leads V4 to V6. The magnitude of precordial ST segment depression (sum of leads V1 to V6) added significant independent prognostic information after adjustment for clinical risk factors; the risk of 30-day mortality increased by 36% for every 0.5 mV of precordial ST segment depression.

CONCLUSIONS

Assessment of the magnitude of precordial ST segment depression is useful for acute risk stratification in patients with an inferior myocardial infarction.

Prognostic significance of maximal precordial ST-segment depression in right (V1 to V3) versus left (V4 to V6) leads in patients with inferior wall acute myocardial infarction

This study examines whether patients with inferior wall acute myocardial infarction (AMI) and maximal ST-segment depression in left precordial leads are at higher risk for in-hospital mortality. The charts of patients (n = 213) with inferior wall AMI and an initial electrocardiogram that displayed peaked, tall T waves or ST-segment elevation with upright T waves in inferior leads were reviewed, after excluding patients with inverted T waves in inferior leads (n = 75). ST-segment deviation from baseline was measured for all leads. Patients were classified into 3 types: I = no precordial ST-segment depression; II = sum of ST-segment depression in leads V1 to V3 equal to or more than the sum of ST-segment depression in leads V4 to V6; and III = maximal precordial ST-segment depression in leads V4 to V6. Thirty-six patients (17%) died in the hospital. In-hospital mortality rates for patients with types I and II were 12% and 10%, respectively, compared with 41% for those with type III (p < 0.0001). Mortality rates in surviving patients were similar for all types up to 1 year after infarction. Multivariate logistic regression models for in-hospital mortality by ST-segment depression type adjusted for age, previous AMI, diabetes mellitus, and thrombolytic therapy revealed that type III pattern was a strong predictive factor for in-hospital mortality (odds ratio = 4.9, p = 0.0008, 95% confidence interval 1.93 to 12.26). Thus, patients with inferior wall AMI and maximal precordial ST-segment depression in leads V4 to V6 are at high risk for in-hospital mortality.

Significance of anterior ST depression in inferior wall acute myocardial infarction

Early tomographic myocardial perfusion imaging with technetium-99m sestamibi was performed during inferior wall acute myocardial infarction to determine the relation between the amount and location of myocardium at risk and the presence or absence or anterior ST depression. The total size of the acute perfusion defect and its lateral and septal borders were measured in 29 consecutive patients who were admitted with > 30 minutes of chest pain and acute inferior ST elevation on their initial electrocardiogram. The 22 patients with anterior ST depression had significantly more left ventricular myocardium at risk than the 19 patients who did not have anterior ST depression (23 +/- 2% of the left ventricle vs 15 +/- 1%, p = 0.008). All 8 patients with > 25% of the left ventricle at risk had anterior ST depression. Patients with anterior ST depression had a significantly greater lateral extent of the acute perfusion defect (49 degrees +/- 8 degrees from the midinferior wall vs 23 degrees +/- 7 degrees, p = 0.002). There was no difference in the septal border of the perfusion defect between patients with and without anterior ST depression (-44 degrees +/- 4 degrees vs -46 degrees +/- 7 degrees, p = NS). No patient had a measurable anterior perfusion defect. Although there is considerable overlap between groups with and without anterior ST depression, anterior ST depression is a simple and readily available indicator of myocardium at risk in inferior wall acute myocardial infarction.

Usefulness of continuous ST monitoring in inferior wall acute myocardial infarction for describing the relation between precordial ST depression and inferior ST elevation

To explore the relation between precordial and inferior ST-segment changes within individual patients, continuous 12-lead electrocardiographic recording was performed in 19 patients with acute inferior infarction given intravenous thrombolytic therapy. Monitoring was performed for 519 +/- 269 minutes. The extent of inferior ST elevation varied considerably with time in all patients. With use of the maximal precordial ST depression recorded to classify patients, 11 had precordial ST depression (sigma V1-3) > 0.2 mV (group A) and 8 had < or = 0.2 mV or no precordial ST depression (group B). The maximal recorded precordial ST depression correlated inversely with the corresponding inferior ST elevation in the 19 patients (r = -0.78, p < 0.001). Within individual patients, continuous 12-lead monitoring revealed a close negative correlation between the inferior and precordial ST levels for the entire recording period in many patients, but 5 of the 19 patients (26%) (2 in group A and 3 in group B) did not have this relation. Moreover, precordial ST depression was not always present during inferior ST elevation in group A patients: 4 of 11 (36%) had some electrocardiographs showing < 0.1 mV precordial ST depression despite summed inferior ST elevation > 0.6 mV. These data indicate that precordial ST depression is not just the simple electrical reciprocal projection of the abnormal inferior wall ST vector, and its fluctuation cannot be predicted by changes in inferior ST level in every patient.(ABSTRACT TRUNCATED AT 250 WORDS)

Long-term prognostic significance of ST segment depression during acute myocardial infarction. The Multicenter Diltiazem Postinfarction Trial Research Group

OBJECTIVES

The purpose of this study was to evaluate the long-term prognostic value of ST segment depression on the electrocardiogram (ECG) in patients with acute myocardial infarction.

BACKGROUND

The prognostic importance of ST segment depression on the ECG has been studied in small groups of patients with infarction, but larger numbers are needed.

METHODS

Coronary care unit ECGs of 1,234 patients who survived the coronary care unit with acute Q wave (n = 896) or non-Q wave (n = 338) myocardial infarction were analyzed for the presence of ST segment depression. Patients were followed up for up to 4 years.

RESULTS

ST segment depression was present in 607 patients. Those with ST segment depression had a 1-year mortality rate of 10.3% compared with a rate of 5.6% for those without ST segment depression (p = 0.002). This effect was seen in both the Q wave and non-Q wave subgroups. Of the 437 patients with anterior ST segment elevation, those with ST segment depression in other regions had a 13.6% 1-year mortality rate compared with a rate of 6.9% for those with no ST segment depression (p = 0.0005). Of the 514 patients with inferior ST segment elevation, those with ST segment depression in other leads had an 11.0% 1-year mortality rate compared with a 1.8% rate for those with no ST segment depression (p = 0.0001). The Cox proportional hazards model showed that ST segment depression was an independent predictor of mortality over the follow-up period.

CONCLUSIONS

ST segment depression on the admitting ECG in patients with acute myocardial infarction is a predictor of increased mortality in the year after infarction.

Comparison of frequency, diagnostic and prognostic significance of pericardial involvement in acute myocardial infarction treated with and without thrombolytics. Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto Miocardico (GISSI)

Data from the Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto Miocardico (GISSI) trial were reviewed to describe the epidemiology of pericardial involvement in patients treated with or without thrombolysis, and to establish its role as a marker of the extent of myocardial infarction and its prognostic value. In both GISSI-1 (n = 11,806) and 2 (n = 12,381), a specific item regarding presence/absence of clinically detected pericardial involvement was included in the study forms. In GISSI-1, patients with ST elevation and depression at the onset of myocardial infarction were admitted, whereas GISSI-2 included only those with ST elevation. Results of univariate analysis are presented as Mantel-Haenszel-Peto odds ratios with 95% confidence intervals. Cox proportional hazards models were used to assess the independent prognostic significance of pericardial involvement for in-hospital and long-term mortality. The main results indicate that: (1) the incidence of pericardial involvement in patients treated with thrombolytic agents is approximately half of that in the control group (6.7 vs 12.0%); (2) the earlier is the treatment, the lower is the incidence of pericardial involvement; (3) pericardial involvement is strongly associated with infarction size, evaluated by electrocardiograms, creatine kinase peak and echo assessments; and (4) pericardial involvement is associated with a higher long-term mortality, but is not an independent prognostic factor (RR 1.02; 95% confidence interval 0.82-1.26). Pericardial involvement is a reliable bedside, cost-free marker of myocardial infarction size and poorer outcome. Because it may elude detection owing to its transitory and often short duration, it should be given greater attention.

Mechanism and significance of precordial ST-segment depression during inferior wall acute myocardial infarction associated with severe narrowing of the dominant right coronary artery

The mechanism and significance of precordial ST depression during inferior wall acute myocardial infarction (AMI) is debated. This study assessed the location and extent of arterial perfusion distribution responsible for this electrocardiographic finding. Intracoronary thallium-201 was injected in 11 patients with 1-vessel right coronary disease to delineate perfusion distribution that was quantitated by a new angiographic distribution score. The angiographic score correlated with posterior (r = 0.84), posterolateral (r = 0.88) and total (r = 0.73) extent of intracoronary thallium distribution. The angiographic distribution score was related to electrocardiographic changes in 16 patients showing an inferior ST-segment elevation during angioplasty (7 with and 9 without precordial ST depression), of which 6 received intracoronary thallium injection. None had thallium distribution in the anterior or septal segment, but there was a trend toward a greater angiographic distribution score and posterior segment thallium score in patients with precordial ST depression. In another 77 patients with inferior wall AMI due to right coronary occlusion (24 with concomitant left anterior descending narrowing), precordial ST depression was present in 16 with and 31 without left anterior descending narrowing (p = NS). The angiographic distribution score was higher in those with than without precordial ST depression (0.59 +/- 0.10 vs 0.44 +/- 0.11, p < 0.001) in both patients with and without left anterior descending disease. The magnitude of both inferior ST elevation and precordial ST depression correlated with the angiographic distribution score, but only precordial ST depression was independently related in multivariate analysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Precordial ST segment depression in patients with Q wave inferior myocardial infarction: role of infarction-associated pericarditis

To examine the diagnostic significance of precordial ST segment depression in Q wave inferior myocardial infarction, 157 consecutive patients were examined carefully by means of auscultation, ECG, and two-dimensional echocardiography. Precordial ST segment depression was transient (lasting < 72 hours from the onset of myocardial infarction) in 63 patients and persistent (> or = 72 hours) in 40. Twenty-eight patients with persistent, 19 patients with transient, and 14 patients without precordial ST segment depression had advanced asynergy (akinesia or dyskinesia) in the posterior segments, whereas 13 patients with persistent, six with transient, and six without precordial ST segment depression had pericardial rub. Patients with persistent precordial ST segment depression had a significantly higher incidence of severe wall motion abnormality (p < 0.01) and inflammation (p < 0.05) of the posterior wall than the other two groups. In 5 of 40 patients with persistent ST segment depression, pericardial rub was detected in the absence of advanced asynergy in the posterior segments. Although not highly sensitive, persistent precordial ST segment depression appeared to be a fairly specific indicator (specificity 92%) of concomitant posterior involvement with severe wall motion abnormality, inflammation, or both.

Significance of reciprocal ST depression in acute myocardial infarction: a study of 258 patients treated by thrombolysis

OBJECTIVE

To investigate the clinical significance of reciprocal ST depression on the presenting electrocardiogram in patients with acute myocardial infarction treated by thrombolysis.

DESIGN

A prospective cohort analytical study.

SETTING

A London district general hospital.

SUBJECTS

Two hundred and fifty eight consecutive patients with acute myocardial infarction treated with thrombolysis.

INTERVENTIONS

All patients underwent treadmill stress testing after a mean (SEM) of 10 (3) days; 200 patients (78%) were referred for coronary arteriography at 30 (16) days.

MAIN OUTCOME MEASURES

Relation between reciprocal ST depression at presentation and several endpoints: time from start of chest pain to hospital presentation, electrocardiographic changes during early treadmill stress testing, presence of multivessel coronary disease, and clinical outcome in terms of recurrent ischaemic events (death, reinfarction, and unstable angina) during a 10 (range six to 12) month follow up.

RESULTS

Presentation was generally early, but in this group of patients reciprocal ST depression was significantly related to the time from the start of symptoms, those with reciprocal change presenting on average one hour earlier than those without. Although reciprocal change on the presenting electrocardiogram was weakly associated with ST depression on treadmill stress testing, it was not indicative of remote ischaemia as a result of multivessel coronary disease or high grade collateralisation of the infarct related artery. There was no association between reciprocal change and the incidence of recurrent ischaemic events.

CONCLUSION

Reciprocal ST depression on the presenting electrocardiogram seems to be a benign electrical phenomenon related to the time from the start of symptoms. It does not necessarily predict an adverse prognosis in patients treated by thrombolysis.

Cardiac imaging after acute myocardial infarction. Identification of patients at continued risk

Diagnostic imaging performed early in the course of acute myocardial infarction provides anatomic and functional information that is useful in assessing patients at risk for future cardiac events and premature death. Early identification of left ventricular dysfunction or complications of myocardial infarction allows appropriate and timely management of high-risk patients and early transfer of stable patients from the intensive care environment. Noninvasive predischarge functional imaging to unmask patients with jeopardized myocardium identifies high-risk patients who may need invasive studies and surgical or interventional treatment. Postdischarge risk stratification with diagnostic imaging provides vital prognostic information in high- and low-risk patients, allowing for appropriate allocation of medical resources.

Correlation of reciprocal ST-segment depression after acute myocardial infarction with coronary angiographic findings

We studied 266 consecutive patients with acute myocardial infarction to assess the significance of electrocardiographic "mirror images". Ninety-four (group A) had anterior wall and 132 (group B) had inferior wall infarction. Thirty-one group A patients had stenosis of the right coronary artery greater than 85% in diameter (subgroup A1), and 63 either had a normal right coronary artery or less than 85% stenosis (subgroup A2). Of group B patients 62 had greater than 85% stenosis of the left anterior descending (subgroup B1) and 70 had a left anterior descending or less than 85% stenosis (subgroup B2). ST-segment depression was significantly greater in depth and duration in subgroup A1 than A2 (p = 0.02) and in subgroup B1 than B2 (p = 0.02, p = 0.01, respectively). Left ventricular ejection fraction was lower in subgroup A1 than A2 (p less than 0.001) and in B1 than B2 (p less than 0.001). There was a strongly positive correlation between depth and duration of ST-segment depression and the Gensini index (r = 0.78, 0.84) for anterior and inferior infarction, respectively. In conclusion, increased depth and duration of ST-segment depression opposite the infarct are indicative of ischemia, and are related to the extent of coronary artery disease, the degree of stenosis of the vessels supplying the opposite wall and of left ventricular dysfunction.

Implications of inferior ST-segment elevation accompanying anterior wall acute myocardial infarction for the angiographic morphology of the left anterior descending coronary artery morphology and site of occlusion

Inferior ST-segment elevation during anterior wall acute myocardial infarction (AMI) due to left anterior descending (LAD) coronary artery occlusion is unusual and was not previously investigated. This study tested the hypothesis that inferior ST-segment elevation during anterior AMI predicts a specific angiographic morphology that satisfies 2 necessary conditions: (1) mass of ischemic anterior wall myocardium is relatively small, resulting in a weaker anterior injury current and less reciprocal inferior ST-segment depression; and (2) there is concomitant inferior wall transmural ischemia that further shifts the inferior ST segments upward. The study group consisted of 42 consecutive patients with anterior AMI undergoing angiography at 4.1 days (range 0 to 14). Coronary angiograms were examined for 3 features: (1) site of LAD artery occlusion (a distal obstruction implying a smaller mass of ischemic anterior wall myocardium), (2) LAD artery extension onto inferior wall of left ventricle (termed a "wrap around" vessel), and (3) collateral flow from LAD artery to inferior wall. The latter 2 features would be expected to contribute to inferior wall transmural ischemia. Acute inferior ST-segment elevation (sum of ST-segment deviation in leads II, III and aVF greater than or equal to 3.0 mm) was seen in 7 patients (16%). A greater number of LAD artery branches proximal to the site of occlusion was significantly correlated with less inferior ST-segment depression (r = 0.59, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Precordial ST segment depression predicts a worse prognosis in inferior infarction despite reperfusion therapy. The Thrombolysis and Angioplasty in Myocardial Infarction (TAMI) Study Group

The impact of associated precordial ST segment depression in inferior myocardial infarction on angiographic and clinical outcomes after thrombolytic therapy and selective coronary angioplasty was studied in 583 patients with acute myocardial infarction. Anterior infarction (Group I), inferior infarction with precordial ST segment depression (Group II) and inferior infarction without precordial ST segment depression (Group III) were present in 289, 135 and 159 patients, respectively. Precordial ST segment depression was more frequent in circumflex than right coronary infarct-related arteries (44 [71%] of 62 versus 91 [40%] of 230; p = 0.000). Although acute patency rates were not statistically different, there was a trend toward different patency rates at day 7 (Group I 88%, Group II 84%, Group III 80%; p = 0.089) partly because of insignificantly higher reocclusion rates in inferior infarction without precordial ST segment depression (Group I 11%, Group II 10%, Group III 18%, p = 0.104). Infarct zone regional wall motion (standard deviations/chord) in inferior infarction was lower with precordial ST segment depression, both acutely (Group I -2.8 +/- 0.9, Group II -2.5 +/- 1.2, Group III 2.0 +/- 1.1; p = 0.000) and at day 7 (Group I -2.2 +/- 1.1, Group II -2.3 +/- 1.1, Group III -1.9 +/- 1.3; p = 0.011). Precordial ST segment depression was associated with a lower ejection fraction in inferior infarction both acutely (Group I 47 +/- 11%, Group II 53 +/- 11%, Group III 58 +/- 9%; p = 0.000) and at day 7 (Group I 49 +/- 12%, Group II 53 +/- 10%, Group III 58 +/- 8%; p = 0.000). Complication rates tended to be higher in inferior infarction when precordial ST segment depression was present. Mortality rates for Groups I, II and III were 8%, 6% and 5%, respectively. These results suggest that precordial ST segment depression in inferior infarction predicts a worse ventriculographic and clinical outcome despite reperfusion therapy.

Twelve-lead electrocardiogram recording during percutaneous transluminal coronary angioplasty. Analysis of reciprocal changes

Coronary angioplasty was used as a human model of transient myocardial ischemia to evaluate the electrocardiographic characteristics and significance of "reciprocal" ST-segment depression and T wave changes. Continuous 12-lead ECGs were recorded before and during coronary angioplasty in 20 patients, 19 of whom had single vessel disease. In 12 of 14 patients, LAD occlusion produced ischemic changes (peaked T and/or ST elevation) in L1, AVL and at least two precordial leads. "Reciprocal" changes (ST depression and/or T inversion) were observed in at least two inferior wall leads. One patient had ST depression in V4-V6 with no change in the inferior leads and in the other the only ECG change was inferior ST depression with partial inversion of the T wave. In four of six patients, RCA occlusion produced ischemic changes in at least two inferior wall leads and "reciprocal" changes in L1, AVL and at least two anterior wall leads. In LAD as well as RCA occlusions "reciprocal" changes were characterized by inversion of the T wave or inversion of its ascending limb with or without ST depression. The magnitude of the ischemic changes tended to be proportional to the magnitude of the "reciprocal" changes. Our data suggest that: (1) "Reciprocal" changes are not a specific indicator of distant myocardial ischemia due to multivessel disease; (2) the magnitude of ischemic changes correlates with the magnitude of "reciprocal" changes; (3) "Reciprocal" changes may be the only manifestation of acute myocardial ischemia; and (4) "Reciprocal" changes may be represented by inversion of the T wave without displacement of the ST-segment.