QRS score as an indicator of myocardial viability after thrombolytic therapy

Revisiting the diagnostic and prognostic significance of high-frequency QRS analysis in cardiovascular diseases: a comprehensive review

Cardiovascular diseases (CVDs) present a significant global public health threat, contributing to a substantial number of cases involving morbidity and mortality. Therefore, the early and accurate detection of CVDs plays an indispensable role in enhancing patient outcomes. Decades of extensive research on electrocardiography at high frequencies have yielded a wealth of knowledge regarding alterations in the QRS complex during myocardial ischemia, as well as the methodologies to assess and quantify these changes. In recent years, the analysis of high-frequency QRS (HF-QRS) components has emerged as a promising non-invasive approach for diagnosing various cardiovascular conditions. Alterations in HF-QRS amplitude and morphology have demonstrated remarkable sensitivity as diagnostic indicators for myocardial ischemia, often surpassing measures of ST-T segment changes. This comprehensive review aims to provide an intricate overview of the current advancements, challenges, and prospects associated with HF-QRS analysis in the field of CVDs.

Differences in the Selvester QRS score after primary PCI strategy and conservative treatment for STEMI patients with negative T waves

BACKGROUND

According to current guidelines, the main indications for PCI in patients with STEMI are ST-segment deviations and defined time from the onset of symptoms. Negative T wave at admission can be a sign of prolonged ischemia or spontaneous reperfusion. In both situations, the urgent intervention is questionable. We evaluated the infarct size and in-hospital mortality in STEMI patients with negative T wave in cases of primary PCI strategy compared with conservative treatment.

METHODS

A retrospective analysis of 116 STEMI patients with negative T wave at the presenting ECG was performed. Sixty-eight patients (59%) underwent primary PCI strategy (PCI group), and 48 (41%) were treated conservatively (non-PCI group). The infarct size estimated by using the Selvester score, and in-hospital mortality were evaluated.

RESULTS

The difference between Selvester score values at admission and at discharge in the non-PCI group was statistically significant (1.48; 95% CI 0.694-2.27), while no significant difference was observed in the PCI group (-0.07; 95% CI -0.546-0.686). The in-hospital mortality was higher in the non-PCI group; however, the numbers were relatively small: PCI 2 (2.9%) and non-PCI 5 (10.4%).

CONCLUSION

In this study, we showed a reduction in the infarct size estimated by Selvester score in STEMI patients with negative T wave who were treated conservatively, while there was no significant change in the infarct size after primary PCI strategy. The higher mortality in patients treated conservatively could be attributed to higher age and comorbidities in the non-PCI group. It seems that conservative treatment strategy might be an option in STEMI patients with negative T wave.

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.

Increase in electrocardiographic R-waves after revascularization in patients with acute myocardial infarction

BACKGROUND

The physiological mechanism of the increase in the electrocardiographic (ECG) R-wave voltage after revascularization in patients with acute myocardial infarction (MI) needs to be elucidated.

METHODS AND RESULTS

One hundred and thirty-eight MI patients (83: anterior MI, 45: inferior MI, 10: lateral MI) underwent ECG and echocardiography in both the acute and subacute phases after emergency revascularization, as well as a resting thallium-201/iodine-123 15-p-iodophenyl-3-(R,S)-methyl pentadecanoic acid myocardial scintigraphy in the acute phase. The total sum of the R-wave voltage (SigmaR) was calculated over multiple leads on ECG for each infarcted lesion. Scintigraphic defect on each tracer was expressed as the percentage (%) defect of the total left ventricular (LV) myocardium. The % defect-discordance on both images in the acute phase and the % increase in SigmaR and the absolute increase in LV ejection fraction from the acute to the subacute phase (DeltaEF) were also calculated. The SigmaR in the subacute phase was significantly greater than that in the acute phase (p<0.0001). The % increase in SigmaR significantly correlated with the DeltaEF (r=0.57, p<0.0001). The % increase in SigmaR also correlated with the % defect-discordance (r=0.68, p<0.0001).

CONCLUSIONS

The increase in the ECG R-wave voltage reflects not only the improvement in myocardial perfusion but also the presence of salvaged myocardium after revascularization in acute MI patients.

Predischarge ST segment and T wave patterns in predicting left ventricular function and myocardial viability in Q wave anterior myocardial infarction patients

The aim of this study was to investigate the correlation between ECG changes prior to discharge and findings of early low dose dobutamine stress echocardiography (LDSE) performed in 6 +/- 2 days, in patients experiencing their first acute anterior MI. A total of 62 patients admitted with their first acute anterior MI were divided into three groups according to the findings of electrocardiograms performed on the 7-10th days: group A, isoelectric ST and negative or positive T wave; group B, ST elevation (> 0.1 mV) and negative T wave; and group C, ST elevation and positive T wave. There were no significant differences between the groups with respect to thrombolytic therapy and reperfusion criteria. In addition, 90% of the patients in group A (20/22), 66% in group B (12/18, P < 0.05 versus group A), and only 54% in group C (12/22, P < 0.01 versus group A) responded to LDSE. The infarct zone wall motion score index (WMSI) measured by LDSE was significantly decreased in group A compared to basal values (from 2.71 +/- 0.65 to 2.07 +/- 0.71 P = 0.02), and it was significantly different compared to groups B and C. Moreover, the serum creatinine kinase level of the patients in group C was higher (P < 0.01 versus group A), whereas the ejection fraction was inferior (group A 48%, group B 47%, and group C 41%, P = 0.04 versus group A). When the correlations between good left ventricular function and terminal QRS distortion, sum ST elevation, the number of leads with ST elevation, ST elevation shape on admission, and ST and T alterations in ECG at discharge were investigated, an independent correlation was found between ST and T alteration in ECG and a WMSI value < 2 at rest or after LDSE (P = 0.03, OR 3.08, 95%CI 1.05-8.98). At the infarct zone of patients with ST elevation and positive T waves, left ventricular function is worse and the viability is less. This simple classification may be useful in predicting left ventricular function at the time of discharge.

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.

Prognostic value of predischarge electrocardiographic measurement of infarct size after thrombolysis: insights from GUSTO I Economics and Quality of Life substudy

BACKGROUND

Current methods for risk stratification after acute myocardial infarction (MI) include several noninvasive studies. In this cost-containment era, the development of low-cost means should be encouraged. We assessed the ability of an electrocardiogram (ECG) MI-sizing score to predict outcomes in patients enrolled in the Economics and Quality of Life (EQOL) sub study of the Global Utilization of Streptokinase and Tissue plasminogen activator for Occluded coronary arteries -I (GUSTO-I) trial.

METHODS

We classified patients by electrocardiographic Selvester QRS score at hospital discharge: those with a score 0-9 versus > or =10. Endpoints were 30-day and 1-year mortality, resource use, and quality-of-life measures.

RESULTS

Patients with a QRS score <10 were well-matched with those with QRS score > or =10 with the exception of a trend to more anterior MI in the higher scored group. Patients with QRS score > or =10 had increased risk of death at 30-days (8.9% vs. 2.9% P < .001), and this difference persisted at 1 year (12.6% vs. 5.4%, P = .001). Recurrent chest pain, use of angiography, and angioplasty were similar during follow-up. However, there was a trend toward less coronary bypass surgery in patients with a QRS score > or =10. Readmission rates were higher at 30 days but similar at 1 year.

CONCLUSIONS

Stratification of patients after acute MI by a simple measure of MI size identifies populations with different long-term prognoses; patients with a QRS score > or =10 (approximately 30% of the left ventricle infarcted) at discharge have poorer outcomes in both the short- and long-term. The standard 12-lead ECG provides a simple, economical means of risk stratification at discharge.

The Relationship Between Terminal QRS Complex Distortion and Early Low Dose Dobutamine Stress Echocardiography in Acute Anterior Myocardial Infarction

Although the damage in myocardial infarction has been demonstrated to be related with the magnitude and number of ST elevation, its relation with terminal distortion of QRS is unclear. The relationship between terminal QRS distortion in ECGs on admission and the results of early low dose dobutamine stress echocardiography (LDSE) performed 6 +/- 2 days later was investigated. Patients admitted to our clinic within the first six hours of their chest pain and without a prior infarction diagnosis were divided into two groups based on the admission electrocardiogram as the absence (QRS-, n = 33) or presence (QRS+, n = 29) of distortion of the terminal portion of the QRS in > or = 2 leads (QRS+; J point at > 50% of the R wave amplitude in lateral leads or presence of ST elevation without S wave in leads V1-V3). There were no significant differences between the groups with respect to thrombolytic therapy or reperfusion criteria. During LDSE, the infarct zone wall motion score index (WMSI) in the QRS- group was significantly decreased relative to baseline (from 2.93 +/- 0.65 to 2.37 +/- 0.84, P = 0.02), and it was significantly different compared with WMSI in the QRS+ group (P = 0.005). Improvement of akinetic regions to hypokinetic regions in the infarct zone (IZ) was found to be 33.5% (44/131) in the QRS- group and 17.8% (27/151 P = 0.004) in the QRS+ group. Furthermore, 55.1% (10/29) of the patients in the QRS+ group and only 18.1% (6/33) of those in the QRS- group did not respond to LDSE (P < 0.05). In multiple logistic regression analysis, while there was no relationship between good left ventricular functions (WMSI < 2) and terminal QRS distortion under basal conditions (P = 0.07), an independent relation was observed to exist between them after LDSE (P = 0.03, OR 4.48, 95% CI, 1.13-17.7). Moreover, plasma CK levels were higher in the QRS+ group (P = 0.03), whereas the ejection fraction was worse (P = 0.01). In both groups, there was no correlation between the Selvester score and left ventricle WMSI at baseline, but this correlation was significantly improved with LDSE (QRS-; r = 0.39 P = 0.02 and QRS+; r = 0.44 P = 0.01) The viability in the IZ is relatively less in those patients with terminal QRS distortion observed in their ECG on admission. This simple classification would be useful in predicting left ventricular function at the time of discharge.

The predischarge electrocardiographic pattern in anterior acute myocardial infarction: relation between evolutionary ST segment and T-wave configuration and prediction of myocardial infarct size and left ventricular systolic function by the QRS Selvester score

Left ventricular systolic function, determined mainly by final infarct size, has a major influence on prognosis after acute myocardial infarction (MI). It was found that infarct size and left ventricular ejection fraction can be predicted using the Selvester QRS-score in patients not receiving reperfusion therapy. We assessed whether the predischarge QRS-score can be used for estimating infarct size and left ventricular ejection fraction in 51 patients with a first anterior MI who had received reperfusion therapy and whether considering the configuration of the ST-segments and T-waves will increase the accuracy of these predictions. All patients had received reperfusion therapy and had predischarge resting 99mTc-sestamibi scan. We determined the Selvester QRS score using the electrocardiograms performed on the same day of the scan. In addition, we divided the patients into 3 groups: A: isoelectric ST and negative T-waves (n = 12); B: ST elevation (> or =0.1 mV) and negative T-waves (n = 23); and C: ST elevation (> or =0.1 mV) and positive T-waves (n = 16). The myocardial perfusion defect extent increased from group A to C (28.5+/-16.4%, 39.4+/-14.8%, and 45.3+/-15.8% in groups A, B, and C. respectively; P = .022). Similarly, the left ventricular ejection fraction decreased (41.7+/-11.6%, 38.4+/-8.1%, and 32.0+/-9.7%, respectively; P = .042) from group A to C. Overall, the correlation between the QRS-score and the myocardial perfusion defect extent (Rho = 0.249; P = .08), and ejection fraction (Rho = -0.229; P = .11) was not good. A statistically significant correlation between the myocardial perfusion defect size and the QRS-score was found only in group A (Rho = 0.599, P = .04). In patients with a first anterior myocardial infarction who underwent reperfusion therapy, the predischarge QRS-score is predictive of infarct size only in those in whom ST elevation resolved completely. In patients with residual ST elevation the Selvester QRS-score is inaccurate in predicting infarct size and left ventricular ejection fraction upon discharge.

Relation between evolutionary ST segment and T-wave direction and electrocardiographic prediction of mycardial infarct size and left ventricular function among patients with anterior wall Q-wave acute myocardial infarction who received reperfusion therapy

In the prethrombolytic era it was found that infarct size and left ventricular ejection fraction could be predicted using the Selvester QRS score. We evaluated whether infarct size and left ventricular ejection fraction could be predicted by the predischarge QRS score in patients who had received reperfusion therapy and whether considering the configuration of the ST segments and T waves would increase the accuracy of these predictions. We evaluated 51 patients with first anterior wall myocardial infarction who had received reperfusion therapy and predischarge resting technetium-99m-sestamibi scan. The electrocardiograms recorded on the same day of the scan were analyzed for the QRS score and were divided into 3 groups: A, isoelectric ST and negative T waves; B, ST elevation (> or =0.1 mV) and negative T waves; and C, ST elevation (> or =0.1 mV) and positive T waves. Groups A, B, and C included 12, 23, and 16 patients, respectively. The myocardial perfusion defect extent increased from groups A to C (median 21%, 37%, and 43.5% in groups A, B, and C, respectively; p = 0.023). Similarly, left ventricular ejection fraction decreased (44%, 38%, and 34%, respectively; p = 0.042) from groups A to C. Overall, the correlation between the QRS score and the myocardial perfusion defect extent (rho 0.249; p = 0.08) and ejection fraction (rho -0.229; p = 0.11) was poor. A statistically significant correlation between myocardial perfusion defect size and QRS score was found only in group A (rho 0.599, p = 0.04). Among patients with anterior myocardial infarction who received reperfusion therapy, the predischarge QRS score was predictive of infarct size only in those in whom ST elevation resolved completely. In patients with residual ST elevation there was no correlation between QRS score and infarct size.