QRS duration and left ventricular ejection fraction (LVEF) in non-ST segment elevation myocardial infarction (NSTEMI)

Clinical significance of R-wave amplitude in lead V1 and inferobasal myocardial infarction in patients with inferior wall myocardial infarction

OBJECTIVE

To assess electrocardiogram (ECG) for risk stratification in inferior ST-elevation myocardial infarction (STEMI) patients within 24 h.

METHODS

Three hundred thirty-four patients were divided into four ECG-based groups: Group A: R V1 <0.3 mV with ST-segment elevation (ST↑) V7-V9, Group B: R V1 <0.3 mV without ST↑ V7-V9, Group C: R V1 ≥0.3 mV with ST↑ V7-V9, and Group D: R V1 ≥0.3 mV without ST↑ V7-V9.

RESULTS

Group A demonstrated the longest QRS duration, followed by Groups B, C, and D. ECG signs for right ventricle (RV) infarction were more common in Groups A and B (p < .01). ST elevation in V6, indicative of left ventricle (LV) lateral injury, was more higher in Group C than in Group A, while the ∑ST↑ V3R + V4R + V5R, representing RV infarction, showed the opposite trend (p < .05). The estimated LV infarct size from ECG was similar between Groups A and C, yet Group A had higher creatine kinase MB isoform (CK-MB; p < .05). Cardiac troponin I (cTNI) was higher in Groups A and C than in B and D (p < .05 and p = .16, respectively). NT-proBNP decreased across groups (p = .20), with the highest left ventricular ejection fraction (LVEF) observed in Group D (p < .05). Group A notably demonstrated more cardiac dysfunction within 4 h post-onset.

CONCLUSIONS

For inferior STEMI patients, concurrent R V1 <0.3 mV with ST↑ V7-V9 suggests prolonged ventricular activation and notable myocardial damage. RV infarction's dominance over LV lateral injury might explain these observations.

Impact of QRS Duration on Non-ST-Segment Elevation Myocardial Infarction (from a National Registry)

QRS duration (QRSd) is ill-defined and under-researched as a prognosticator in patients with non-ST-segment myocardial infarction (NSTEMI). We analyzed 240,866 adult (≥18 years) hospitalizations with non-ST-segment elevation myocardial infarction using data from the United Kingdom Myocardial Infarction National Audit Project. Clinical characteristics and all-cause in-hospital mortality were analyzed according to QRSd, with 38,023 patients presenting with a QRSd >120 ms and 202,842 patients with a QRSd <120 ms. Patients with a QRSd >120 ms were more frequently older (median age of 79 years vs 71 years, p <0.001), and of white ethnicity (93% vs 91%, p <0.001). Patients with a QRSd <120 ms had higher frequency of use of aspirin (97% vs 95%, p <0.001), P2Y12 inhibitor (93% vs 89%, p <0.001), angiotensin-converting enzyme inhibitor/angiotensin receptor blocker (82% vs 81%, p <0.001) and β blockers (83% vs 78%, p <0.001). Invasive management strategies were more likely to be used in patients with QRSd <120 ms including invasive coronary angiography (72% vs 54%, p <0.001), percutaneous coronary intervention (46% vs 33%, p <0.001) and coronary artery bypass graft surgery (8% vs 6%, p <0.001). In a propensity score matching analysis, there were no differences between the 2 groups in the adjusted rates of in-hospital all-cause mortality (odds ratio 0.94, 95% confidence interval 0.86 to 1.01) or major adverse cardiac events (odds ratio 0.94, 95% confidence interval 0.85 to 1.02) during the index admission. In conclusion, prolonged QRSd >120 ms in the context of non-ST-segment myocardial infarction is not associated with worse in-hospital mortality or the outcomes of major adverse cardiac events.

Subtle QRS changes are associated with reduced ejection fraction, diastolic dysfunction, and heart failure development and therapy responsiveness: Applications for artificial intelligence to ECG

BACKGROUND

Since the last century, the electrocardiogram (ECG) remains the non-invasive test, that is, most easily accessible, feasible, and inexpensive for cardiology assessment. In past years, many novel ECG indexes and patterns have been published that allow for a more advanced evaluation of what is currently being done, especially based on subtle QRS changes and patterns.

OBJECTIVE

The objective of the study was to provide an update on the evidence and clinical applications of these ECG subtle QRS changes and patterns associated with heart disease.

METHODS

Through the literature review, we will highlight the subtle QRS changes and patterns associated with heart disease, mainly focusing on QRS duration, voltage, morphology, axis, and QT interval.

RESULTS

Small increases in QRS duration are associated with a reduction in left ventricular ejection fraction (EF), increased cardiac chamber dimensions, and risk for incident heart failure (HF). Moreover, fragmentation of the QRS complex is associated with myocardial fibrosis and is a substrate for developing arrhythmic events. Besides, low amplitude QRS voltage is associated with congestive HF, and an increase in the voltage of the QRS complexes is associated with the effectiveness of diuresis treatment. Furthermore, small increases in QT interval are associated with diastolic dysfunction due to impaired sarcoplasmic reticulum calcium handling as occurs in myocardial ischemia, hypertension, or diabetes. On the other hand, in patients with left ventricular dysfunction, the QRS area is associated with clinical and echocardiographic response to cardiac resynchronization therapy regardless of the type of bundle branch block. In addition, subtle ECG changes and patterns in the left bundle branch block are associated with concomitant right ventricular dilation, mostly based on the QRS axis and voltage. Notwithstanding, to identify these subtle changes in QRS require exact manual measurements that can take time. In this regard, applying artificial intelligence (AI) to the ECG can make a quicker and more complete assessment, as well as provide a low cost when applied to large populations.

CONCLUSION

We provided an update on the evidence and clinical applications of these subtle QRS changes and patterns associated with diastolic dysfunction, reduced EF, and HF development and therapy responsiveness, as well as their applications for AI to ECG.

Cardiac Magnetic Resonance Feature Tracking: A Novel Method to Assess Left Ventricular Three-Dimensional Strain Mechanics After Chronic Myocardial Infarction

RATIONALE AND OBJECTIVES

This study was designed to assess left ventricular deformation after chronic myocardial infarction (CMI) using cardiac magnetic resonance feature tracking (CMR-FT) technology, and analyze its relationship with left ventricular ejection fraction (LVEF) and infarcted transmurality.

MATERIALS AND METHODS

Ninety-six patients with CMI and 72 controls underwent 3.0 T CMR scanning. Strain parameters were measured by dedicated software, including global peak longitudinal strain (GPLS), global peak circumferential strain (GPCS), global peak radial strain (GPRS), segmental peak longitudinal strain (PLS), peak circumferential strain (PCS), and peak radial strain (PRS). All enhanced myocardium segments were divided into subendocardial infarction (SI) and transmural infarction (TI) group. Pearson, intraclass correlation coefficient and receiver operating characteristic analysis were performed to compare the parameters' mean values between SI and TI groups.

RESULTS

GPLS, GPRS, and GPCS in CMI group were significantly decreased comparing with control group. PRS and PCS in TI group were significantly lower than those in SI group, whereas no statistical difference was observed in PLS. In Pearson correlation analysis, LVEF was strongly correlated with GPLS, GPRS, and GPCS in CMI patients. Additionally, excellent reproducibility of all strain parameters was observed. In receiver operating characteristic analysis, segmental PRS and PCS might differentiate SI from TI with higher diagnostic efficiency (p < 0.05), while PLS was less valuable (p > 0.05).

CONCLUSION

CMR-FT could noninvasively and quantitatively assess global and regional myocardial strain in CMI patients with excellent reproducibility and strong correlation with LVEF. Additionally, segmental myocardial strain parameters indicate potential clinical value in differentiating myocardial infarction subtype.

Variations of electrocardiographic parameters during hospitalization predict long-term outcomes in patients with non-ST-segment elevation myocardial infarction

BACKGROUND

Electrocardiogram is an essential modality for diagnosis and early risk stratification for patients with acute coronary syndrome (ACS), but its long-term prognostic value has not been well studied. This study tried to investigate the long-term prognostic value of variations of ECG parameters at admission and discharge in patients with non-ST-segment elevation myocardial infarction (NSTEMI).

METHODS

A total of 170 NSTEMI patients were recruited consecutively from 2013 to 2014 in West China Hospital of Sichuan University. All subjects' ECGs at admission and discharge were reviewed. Follow-up was performed, and the survival difference between groups was analyzed.

RESULTS

Comparing with at admission, NSTEMI patients at discharge with a wider P wave (19.4% vs. 8.1%, p = 0.047), with new-onset PtfV1 positive (31.2% vs. 8.1%, 11.5%, 13.3%, p = 0.147) and with a greater number of leads showing ST depression (21.9% vs. 10.3%, p = 0.037) were prone to MACEs during long-term follow-up. The independent risk factors for the primary endpoints determined using a multivariate cox regression were new-onset PtfV1 positive during hospitalization (HR = 4.705, 95% CI = 1.457-15.197, p = 0.010) and prolonged QRS duration at discharge comparing to admission (HR = 2.536, 95% CI = 1.057-6.083, p = 0.030), besides diabetes mellitus, stage 3 hypertension, and multiple vessel lesions.

CONCLUSION

Discharge ECG with new-onset PtfV1 positive and prolonged QRS duration were independent risk factors for recurrence of MACEs in NTEMI patients. The differences of ECG parameters between at admission and discharge, including P-wave duration, number of leads with ST-segment depression, carried long-term prognostic information for NSTEMI patients.