The use of the electrocardiogram to identify epicardial coronary and tissue reperfusion in acute myocardial infarction

Assessment of Selected Baseline and Post-PCI Electrocardiographic Parameters as Predictors of Left Ventricular Systolic Dysfunction after a First ST-Segment Elevation Myocardial Infarction

OBJECTIVE

To assess the performance of ten electrocardiographic (ECG) parameters regarding the prediction of left ventricular systolic dysfunction (LVSD) after a first ST-segment-elevation myocardial infarction (STEMI).

METHODS

We analyzed 249 patients (74.7% males) treated with primary percutaneous coronary intervention (PCI) included into a single-center cohort study. We sought associations between baseline and post-PCI ECG parameters and the presence of LVSD (defined as left ventricular ejection fraction [LVEF] ≤ 40% on echocardiography) 6 months after STEMI.

RESULTS

Patients presenting with LVSD (n = 52) had significantly higher values of heart rate, number of leads with ST-segment elevation and pathological Q-waves, as well as total and maximal ST-segment elevation at baseline and directly after PCI compared with patients without LVSD. They also showed a significantly higher prevalence of anterior STEMI and considerably wider QRS complex after PCI, while QRS duration measurement at baseline showed no significant difference. Additionally, patients presenting with LVSD after 6 months showed markedly more severe ischemia on admission, as assessed with the Sclarovsky-Birnbaum ischemia score, smaller reciprocal ST-segment depression at baseline and less profound ST-segment resolution post PCI. In multivariate regression analysis adjusted for demographic, clinical, biochemical and angiographic variables, anterior location of STEMI (OR 17.78; 95% CI 6.45-48.96; p < 0.001), post-PCI QRS duration (OR 1.56; 95% CI 1.22-2.00; p < 0.001) expressed per increments of 10 ms and impaired post-PCI flow in the infarct-related artery (IRA; TIMI 3 vs. <3; OR 0.14; 95% CI 0.04-0.46; p = 0.001) were identified as independent predictors of LVSD (Nagelkerke's pseudo R2 for the logistic regression model = 0.462). Similarly, in multiple regression analysis, anterior location of STEMI, wider post-PCI QRS, higher baseline number of pathological Q-waves and a higher baseline Sclarovsky-Birnbaum ischemia score, together with impaired post-PCI flow in the IRA, higher values of body mass index and glucose concentration on admission were independently associated with lower values of LVEF at 6 months (corrected R2 = 0.448; p < 0.00001).

CONCLUSIONS

According to our study, baseline and post-PCI ECG parameters are of modest value for the prediction of LVSD occurrence 6 months after a first STEMI.

Comparison of the improvement in myocardial perfusion and function in cases of rapid and slow electrocardiographic stage dynamics between patients with TIMI-3 flow after primary angioplasty for acute myocardial infarction

BACKGROUND AND OBJECTIVE

Post-PCI TIMI flow grade 3 in infarct-related artery not always is associated with follow-up improvement in myocardial perfusion and function. We compared the improvement in myocardial perfusion and function in cases of rapid and slow electrocardiographic (ECG) stage dynamics between patients with TIMI-3 flow after primary angioplasty for acute myocardial infarction (MI).

MATERIALS AND METHODS

Ten patients with post-PCI TIMI-3 flow were divided into group A (n=50, no rapid change of ECG stages) and group B (n=50, with a ≥2 ECG stages per 2 days change rate).

RESULTS

There were no significant changes after 3 months in scintigraphic (ejection fraction 44.6±9.3% vs. 42.0±3.4%, P=0.4; perfusion deficit severity 3.0±0.7 vs. 2.3±0.8, P=0.1) and echocardiographic (dysfunction score 1.9±0.2 vs. 1.6±0.5, P=0.2) data in group A. Scintigraphic data improved (ejection fraction 34.6±3.9% vs. 52.0±7.3, P=0.03; perfusion deficit severity 2.8±0.6 vs. 1.5±0.8, P=0.03) and changes in echocardiographic data were of borderline significance (dysfunction score 1.8±0.2 vs. 1.4±0.4, P=0.06) in group B.

CONCLUSIONS

There was not any change in myocardial perfusion and function in a case of slow change of ECG stages after reached post-PCI TIMI flow grade 3, while myocardial perfusion improved and function tended to improve in a case of the rate at least two ECG stages in 2 days after primary angioplasty for acute MI.

Screening and identifying the myocardial-injury protective ingredients from Sheng-Mai-San

CONTEXT

Sheng-Mai-San (SMS) has been used for the treatment of cardiovascular disease for many years in China.

OBJECTIVES

This study investigated the protective effects and active ingredients of SMS on myocardial injury (MI) in mice.

MATERIALS AND METHODS

SMS and n-butanol extraction of SMS (SMS-Bu) were prepared and administered to ISO-treated mice once a day for 7 consecutive days. The doses were equivalent to the raw medicinal herbs of SMS 5.72, 2.86 and 1.43 g/kg/d, respectively. Propranolol was used as positive control. Serum biomarkers, histopathological and electrocardiographic were evaluated.

RESULTS

Serum lactate dehydrogenase, creatine kinase and myeloperoxidase increased to 4473.6 ± 322.5, 950.0 ± 35.0 and 90.4 ± 12.2 U/L in the model group. SMS and SMS-Bu groups showed a decrease from 10 to 29% for lactate dehydrogenase and from 17 to 42% for creatine kinase, respectively. Both SMS and SMS-Bu significantly attenuated the myeloperoxidase activities (from 42 to 56%) and malondialdehyde levels (from 25 to 45%) compared with the model group. Decreased superoxide dismutase activities in ISO-treated mice were elevated from 19 to 59% when treated with SMS and SMS-Bu. These biochemical results were supported by electrocardiogram (ECG) and histopathological observations. Furthermore, 8 ginsenosides and 16 lignans were identified in SMS-Bu.

CONCLUSION

These findings suggested that SMS-Bu was the mainly active fraction of SMS which exerted its beneficial effects on MI mainly through protecting myocardial tissue and reducing oxidative damage, and the ginsenosides and lignans may serve as active ingredients of SMS for the treatment of MI.

Prediction of improvement in left ventricular function during a 1-year follow-up after acute myocardial infarction by the degree of acute resolution of electrocardiographic changes

BACKGROUND AND PURPOSE

Reperfusion therapy results in better left ventricle (LV) function in cases of successful myocardial reperfusion; however, insufficient reperfusion or reocclusion of the infarct-related artery is associated with LV dysfunction. This study was proposed to determine whether the rate of ECG stage dynamics, after mechanical, thrombolytic, or spontaneous recanalization, is a predictor of improvement in LV function.

METHODS

Twenty-seven consecutive patients, observed for 1 year, were divided into group A (11, change rate of > or =2 ECG stages per 2 days), group B (13, no rapid change), and cases with reocclusion (3).

RESULTS

Clinical and radiographic signs of heart failure tended to decrease in group A but tended to increase in other cases. Echocardiographic dyssynergic score decreased, and LV ejection fraction increased only in group A: 4.3 +/- 1.2 vs 2.7 +/- 1.5, P = .04, and 42.0 +/- 4.8 vs 46.0 +/- 8.3, P = .049, respectively; in group B, the values were 3.4 +/- 2.4 vs 3.4 +/- 2.2 and 44.0 +/- 6.9 vs 43.8 +/- 9.3, respectively.

CONCLUSIONS

Rapid ECG stage changes predict follow-up improvement in LV function.

Fibrin(ogen) and its fragments in the pathophysiology and treatment of myocardial infarction

The occlusion of a coronary artery leads to ischemia of the myocardium, while permanent occlusion results in cell death and myocardial dysfunction. Early restoration of blood flow is the only means to reduce or prevent myocardial necrosis, but-paradoxically-reperfusion itself contributes to injury of the heart. In animal models, this phenomenon is well described, and there are many different unrelated approaches to reduce reperfusion injury. In humans, however, pharmacological interventions have so far failed to reduce myocardial reperfusion injury. We summarize the pathogenesis of reperfusion injury, detailing the role of fibrin(ogen) and its derivatives. Moreover, we introduce a new concept for fibrin derivatives as potential targets for reperfusion therapy.

Ischemia-induced ST-segment elevation: classification, prognosis, and therapy

The standard 12-lead electrocardiogram (ECG) remains the most useful tool for the diagnosis, early risk stratification, triage, and guidance of therapy in patients with acute coronary syndromes. However, the initial and the terminal part of the QRS complex, the ST segments, and the T waves are influenced by anatomical and metabolic factors such as the "myocardium at risk" and "severity" and "duration" of ischemia. Moreover, there are complex interactions between all these factors. The ECG can identify potential candidates for reperfusion therapy as well as the completeness and success of reperfusion, whereas it can also identify those patients who will have no benefit from reperfusion because of either late arrival or nonischemic etiologies of ECG changes. These patients may have a "pseudo" ST-elevation acute myocardial infarction (STEAMI) or "pseudo-pseudo" STEAMI. The presence of Q waves and additional ST-segment depression and T-wave inversion on the admission ECG in patients with STEAMI may provide us information regarding the potential myocardial reserves, and various ECG scoring systems are in current use for that purpose. The pattern and timing of changes in Q waves, ST segment, and T waves may all be markers of the patency status of the infarct-related artery. We review and discuss each of the dynamic ECG variables during ischemia and reperfusion: the initial QRS (Q and R waves), the terminal QRS (Sclarovsky-Birnbaum score), the ST segment, and the T waves.

Electrocardiogram of acute ST-elevation myocardial infarction: the significance of the various "scores"

The Electrocardiogram has extensively been used for evaluation and triage of patients with acute chest pain. The clinician admitting a patient with ST elevation acute myocardial infarction should be able to estimate the size and location of the ischemic area at risk, how much of the ischemic myocardium has already undergone irreversible necrosis by the time of presentation, and the "severity of ischemia" (or what is the rate of progression of necrosis as long as ischemia continues). The electrocardiographic variables that are used to make these estimates are the initial portion of the QRS (Q and R waves), the terminal portion of the QRS (the S waves and the J-point), the ST segment, and the configuration of the T waves. This editorial discuss the ability to predict each of the "physiological" parameters using the above mentioned electrocardiographic variables.

Prediction of decrease in myocardial perfusion defect size and severity during a 3-month follow-up by the degree of acute resolution of electrocardiographic changes

Myocardial perfusion in infarct-related artery (IRA) distribution improves progressively until a few months after successful reperfusion therapy. We assessed the rate of electrocardiographic (ECG) stage dynamics to predict perfusion improvement after mechanical, thrombolytic, or spontaneous recanalization of IRA. Thirteen patients were divided into group A (n = 8, with > or = 2 ECG stages per 2-day change rate) and group B (n = 5, no rapid change of ECG stages). There were no significant technetium Tc 99m sestamibi scintigraphic differences between the groups 3 days after recanalization; however, after 3 months, perfusion deficit size (2.8 +/- 1.8 vs 4.8 +/- 1.2, P < or = .03) and severity (1.8 +/- 0.9 vs 3.0 +/- 0, P < or = .03) were smaller in group A vs group B. The prediction sensitivity of the method was 87.5% for decrease in size and 100% for decrease in severity of perfusion defect; the specificity was 80% and 100%, respectively. A change rate of 2 or more ECG stages per 2 days predicts follow-up improvement of myocardial perfusion after IRA recanalization.

Single lead ST-segment recovery: a simple, reliable measure of successful fibrinolysis after acute myocardial infarction

BACKGROUND

Successful reperfusion after acute ST-elevation myocardial infarction improves prognosis. Among the different electrocardiographic markers of reperfusion, sum ST resolution is considered the hallmark of reperfusion, but is cumbersome to use.

METHODS

To assess the usefulness of a single lead ST resolution at 90 minutes after fibrinolysis compared with the sum ST resolution in predicting Thrombolysis in Myocardial Infarction (TIMI) grade 3 flow, we used prospectively collected data from the Limitation of Myocardial Injury Following Thrombolysis in Acute Myocardial Infarction (LIMIT-AMI) study. All patients had electrocardiograms recorded at presentation and 90 minutes and a coronary angiogram 90 minutes after fibrinolysis.

RESULTS

Infarction artery patency was assessed in 238 patients with 4 different ST resolution criteria: single lead ST resolution > or =50% and > or =70% and sum ST resolution > or =50% and > or =70%. The most sensitive criteria for TIMI grade 3 flow was single lead ST resolution > or =50% (sensitivity rate, 70%; specificity rate, 54%), whereas sum ST resolution > or =70% was most the specific criteria (sensitivity rate, 45%; specificity rate, 79%). The proportion of patients with TIMI grade 3 flow was similar in all 4 ST resolution groups (P =.84). Pre-discharge infarction size and ejection fraction were also similar. No single lead or sum lead measure of ST resolution was significantly associated with an increased risk of death, heart failure, or reinfarction.

CONCLUSION

We propose that single lead ST-resolution > or =50% as an optimal electrocardiographic indicator for successful reperfusion 90 minutes after fibrinolysis. This simple electrocardiographic measure should be combined with bedside clinical and hemodynamic assessment to optimize decision making after fibrinolysis.

The Effect of Tirofiban on ST Segment Resolution in Patients With Non-ST Elevated Myocardial Infarction

ST segment resolution in ST elevated myocardial infarction has independent predictive value for congestive heart failure and death at 30 days. ST segment depression in unstable angina pectoris (UAP) and non-ST elevated myocardial infarction (NSTEMI) predicts high risk of MI and death and may discriminate patients likely to have greater benefit from aggressive antithrombotic and interventional therapy. This study assessed the effect of tirofiban added to conventional treatment on ST segment resolution in NSTEMI patients. Sixty-four patients were randomized to one of the two groups: 32 patients received conventional treatment while tirofiban was added in the second group of 32 patients. In the first group, 6 patients refused to participate further after giving initial informed consent while 1 patient in the tirofiban group dropped out. We had 26 patients (mean age, 59 years) in the conventional treatment group and 31 patients (mean age, 59 years) received also tirofiban. Tirofiban was administered by intravenous infusion over a 72 hour period. More than 50% regression of depression was considered to be ST segment resolution. The characteristics of the two groups were comparable (Table I). The ST segment resolution evolution did not differ at the 4th and 24th hours between the two groups. Significant differences occurred in the 72nd hour ECG (Table III). ST resolution was present in 67.9% of the tirofiban patients and in 32.1% of the conventional treatment group (P < 0.05). Tirofiban treatment was not associated with an increase in major bleeding even though there was a trend toward an increase in minor bleeding cases and did not influence the occurrence of refractory angina pectoris.

Improved prognosis of patients presenting with clinical markers of spontaneous reperfusion during acute myocardial infarction

OBJECTIVE

To describe the clinical features, management, and prognosis of patients presenting with clinical markers of spontaneous reperfusion (SR) during acute myocardial infarction (AMI).

DESIGN

Cohort study.

SETTING

National registry of 26 coronary care units.

PATIENTS

2382 consecutive patients with AMI.

MAIN OUTCOME MEASURES

Patient characteristics, management, and mortality.

RESULTS

The incidence of SR was 4% of patients (n = 98) compared with thrombolytic treatment (n = 1163, 49%), primary angioplasty (n = 102, 4%), and non-reperfusion (n = 1019, 43%). SR patients were more likely to develop less or no myocardial damage as indicated by a higher percentage of non-Q wave AMI (58% v 32%, 47%, and 44%, respectively, p < 0.0001), aborted AMI (25% v 9%, 8%, and 12%, p < 0.001), and lower peak creatine kinase (503 v 1384, 1519, and 751 IU, p < 0.0001). SR patients, however, were more likely to develop recurrent ischaemic events (35% v 17%, 12%, and 16%, respectively; p < 0.001) and subsequently were more likely to be referred to coronary angiography (67%), angioplasty (41%), or bypass surgery (16%, p < 0.001). Mortality at 30 days (1% v 8%, 7%, and 13%, respectively, p < 0.0001) and one year (6% v 11%, 12%, and 19%, p < 0.0001) was significantly lower for SR patients than for the other subgroups. By multivariate analysis, SR remained a strong determinant of 30 day survival (odds ratio (OR) 0.16, 95% confidence interval (CI) 0.01 to 0.74). At one year, the association between SR and survival decreased (OR 0.49, 95% CI 0.18 to 1.13).

CONCLUSIONS

Clinical markers of SR are associated with greater myocardial salvage and favourable prognosis. The vulnerability of SR patients to recurrent ischaemic events suggests that they need close surveillance and may benefit from early intervention.