Ischemic QRS prolongation as a biomarker of severe myocardial ischemia

Critical Convex-Type ST Elevation Correlate With Ventricular Tachyarrhythmia in Takotsubo Cardiomyopathy

BACKGROUND

Ventricular tachyarrhythmia (VT) occasionally occurred in patients with Takotsubo cardiomyopathy (TC). Two convex-type ST elevations were significantly related to VT in coronary artery disease.

METHODS

This study assessed the correlation between VT and critical ECG patterns, as well other independent predictive factors of in-hospital outcome. Fifty-five consecutive patients fulfilled the diagnostic criteria of Takotsubo Italian Network (TIN) were retrospectively enrolled. The patients were classified into two groups according to their critical ECG patterns and VT occurrence. In-hospital outcomes and influencing factors were analyzed.

RESULTS

The incidence of VT was higher in the critical ECG group than in the Noncritical ECG group (43.8% vs. 2.6%, p < 0.001). In-hospital death was more common in the critical ECG group than in the Noncritical ECG group (25.0% vs. 5.1%, p = 0.032). The composite end-point (combined VT and in-hospital death) revealed significant differences between these two groups (50.0% vs 7.7%, p < 0.001). Multi-variate analysis proved critical ECG type as one independent risk factor of VT (odds ratio [OR] = 61.8, p = 0.009) and the composite end-point (OR = 12.4, p = 0.007). The prolong QRS width ( ≥ 105 ms) was another independent factor for predicting VT (OR = 1.06, p = 0.022) and composite end-point (OR = 1.05, p = 0.017).

CONCLUSIONS

Critical ECG types including tombstoning ST elevation and lambda-wave ST elevation have strong impact on short-term outcomes. Additionally, conduction disturbance with prolong QRS ≥ 105 ms also has independent predicting role for poor prognosis.

Pseudo precordial ST-segment depression

We present a case with acute coronary syndrome and very unusual QRS widening in the acute phase. The case highlights that non-specific intraventricular conduction delay should be considered as a high risk ECG pattern predicting poor prognosis.

Clinical outcomes of ST-elevation myocardial infarction patients who present special forms of ST-segment elevation

BACKGROUND

There are several patterns of special ST-segment elevation morphology in patients with ST-elevation myocardial infarction (STEMI), but their effect on prognosis is unclear. We, therefore, investigated the mortality of patients with these patterns by comparing them to patients with typical ST-segment morphologies.

METHODS

This observational study assessed 1277 consecutive patients with STEMI. Their initial electrocardiograms were analyzed quantitatively and divided into four categories: typical (n = 1138), Tombstone (n = 62), Triangular (n = 39), and Lambda patterns (n = 38). The primary outcome was death (all causes).

RESULTS

The Triangular and Lambda pattern patients had high proportions of cardiogenic shock (15.8%, 9.7%, 66.7%, and 47.4%, P < 0.01, for typical, Tombstone, Triangular, and Lambda, respectively) and out-of-hospital cardio-pulmonary arrests (4.8%, 6.5%, 38.5%, and 26.3%, P < 0.01). They also had higher frequencies of multivessel disease (37.2%, 30.7%, 66.7%, and 55.3%, P < 0.01) and left main trunk lesion (2.8%, 0%, 35.9%, and 13.2%, P < 0.01). During a median observation period of 717 days, the mortality rates were 18.3%, 17.7%, 71.8%, and 52.6% (P < 0.01; 7.4%, 9.7%, 53.9%, and 42.1% within 30-days, P < 0.01), respectively. The hazard ratios were 1.3 (95% CI: 0.6-3.0. P = 0.51) in Tombstone, 9.6 (95% CI: 6.0-15.3, P < 0.01) in Triangular, and 6.7 (95% CI: 4.0-11.2, P < 0.01) in Lambda patterns when referenced to typical patterns.

CONCLUSION

The mortality rate in STEMI patients with Triangular and Lambda patterns was higher than that of those with typical and Tombstone patterns.

The ratio of QRS/RV6-V1: a new electrocardiographic predictor of short- and long-term adverse clinical outcomes in patients with acute myocardial infarction combined with new-onset right bundle branch block

Background

A few studies have focused on electrocardiography (ECG) parameters correlating with clinical prognosis in patients with acute myocardial infarction (AMI) combined with new-onset right bundle branch block (RBBB).

Objective

To assess the prognostic value of a new ECG parameter, namely, the ratio of QRS duration/RV₆-V₁ interval (QRS/RV₆-V₁), in patients with AMI combined with new-onset RBBB.

Materials and methods

A total of 272 AMI patients combined with new-onset RBBB who received primary percutaneous coronary intervention (P-PCI) were retrospectively enrolled in the study. First, the patients were divided into survival group and non-survival group. Demographic, angiographic, and ECG characteristics were compared between the two groups. Receiver operating characteristic (ROC) curve was used to screen the best ECG parameter for predicting 1-year mortality. Second, the ratio of QRS/RV₆-V₁, a continuous variable, was converted to the high ratio group and low ratio group according to the optimal cutoff value point determined by the X-tile software. We compared the patient's demographic, angiographic, and ECG characteristics, in-hospital major adverse cardiovascular events (MACE), and 1-year mortality between the two groups. Multivariate logistic and Cox regressions were used to evaluate whether the ratio of QRS/RV₆-V₁ was an independent prognostic factor of in-hospital MACE and 1-year mortality.

Results

The ROC curve showed that the ratio of QRS/RV₆-V₁ had a higher value for predicting in-hospital MACE and 1-year mortality than the QRS duration, RV₆-V₁ interval, and RV₁ interval. The patients in the high ratio group had significantly higher CK-MB peak and Killip class, lower ejection fraction (EF%), higher ratio of the left anterior (LAD) descending artery as infarct-related artery (IRA), and longer total ischemia time (TIT) than those in the low ratio group. The QRS duration was wider in the high ratio group than that in the low ratio group, whereas RV₆-V₁ was narrower in the high ratio group compared with that in the low ratio group. The in-hospital MACE rate (93.3% vs. 31.0%, p < 0.001) and 1-year mortality rate (86.7% vs. 13.2%, p < 0.001) in the high ratio group were higher than those in the low ratio group. The higher ratio of QRS/RV₆-V₁ was an independent predictor of in-hospital MACE (odds ratio, 8.55; 95% CI, 1.40-52.37; p = 0.02) after adjusting other confounders. Cox regression showed that the higher ratio of QRS/RV₆-V₁ predicted higher 1-year mortality of the patients with AMI combined with new-onset RBBB [hazard ratios (HR), 12.4; 95% CI, 7.26-21.22); p < 0.001] than the lower ratio of QRS/RV₆-V₁, and the HR still stayed at 2.21 even after a multivariable adjustment (HR, 2.21; 95% CI, 1.05-4.64); p = 0.037).

Conclusion

According to the results of our study, the high ratio of QRS/RV₆-V₁ (>3.0) was a valuable predictor of short- and long-term adverse clinical outcomes in AMI patients combined with new-onset RBBB. The implications of the high ratio of QRS/RV₆-V₁ were severe ischemia and pseudo synchronization between bi-ventricle.

Ischemic QRS prolongation as a predictor of ventricular fibrillation in a canine model

OBJECTIVES

An acute coronary occlusion and its possible subsequent complications is one of the most common causes of death. One such complication is ventricular fibrillation (VF) due to myocardial ischemia. The severity of ischemia is related to the amount of coronary arterial collateral flow. In dog studies collateral flow has also been shown to be associated with QRS prolongation. The aim of this study was to investigate whether ischemic QRS prolongation (IQP) is associated with impending VF in an experimental acute ischemia dog model.

METHODS

Degree of IQP and occurrence of VF were measured in dogs (n = 21) during coronary occlusion for 15 min and also during subsequent reperfusion (experiments conducted in 1984).

RESULTS

There was a significant difference in absolute IQP between dogs which developed VF during reperfusion (47 ± 29 ms, mean ± SD) and those which did not (12 ± 10 ms; p = .001).

CONCLUSIONS

IQP during acute coronary occlusion is associated with reperfusion VF in an experimental dog model and might therefore be a potential predictor of malignant arrhythmias in patients with acute coronary syndrome.

Ischemic QRS prolongation as a biomarker of myocardial injury in STEMI patients

BACKGROUND

Patients with acute coronary occlusion (ACO) may not only have ischemia-related ST-segment changes but also changes in the QRS complex. It has recently been shown in dogs that a greater ischemic QRS prolongation (IQP) during ACO is related to lower collateral flow. This suggests that greater IQP could indicate more severe ischemia and thereby more rapid infarct development. Therefore, the purpose was to evaluate the relationship between IQP and measures of myocardial injury in patients presenting with acute ST-elevation myocardial infarction (STEMI).

METHODS

Seventy-seven patients with first-time STEMI were retrospectively included from the recently published SOCCER trial. All patients underwent a cardiac magnetic resonance (CMR) examination 2-6 days after the acute event. Infarct size (IS), myocardium at risk (MaR), and myocardial salvage index (MSI) were assessed and related to IQP. IQP measures assessed were; computer-generated QRS duration, QRS duration at maximum ST deviation, absolute IQP and relative IQP, all derived from a pre-PCI, 12-lead ECG.

RESULTS

Median absolute IQP was 10 ms (range 0-115 ms). There were no statistically significant correlations between measures of IQP and any of the CMR measures of myocardial injury (absolute IQP vs IS, r = 0.03, p = 0.80; MaR, r = -0.01, p = 0.89; MSI, r = -0.05, p = 0.68).

CONCLUSIONS

Unlike previous experimental studies, the IQP was limited in patients presenting at the emergency room with first-time STEMI and no correlation was found between IQP and CMR variables of myocardial injury in these patients. Therefore, IQP does not seem to be a suitable biomarker for triaging patients in this clinical context.