Acute myocardial infarction complicated by shock: outcome analysis based on initial electrocardiogram

Influence of Right and Left Bundle Branch Block in Patients With Cardiogenic Shock and Cardiac Arrest

OBJECTIVES

The study investigates the prognostic impact of right bundle branch block (RBBB) and left bundle branch block (LBBB) in patients with cardiogenic shock (CS) compared with no bundle branch block (BBB). In patients with heart failure, existence of RBBB and LBBB has influence on prognosis.

DESIGN

Prospective registry-study.

SETTING

ICU of a tertiary academic hospital in Germany.

PATIENTS

Adult patients with CS.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Consecutive patients with CS were included. The prognostic impact of RBBB and LBBB on 30-day all-cause mortality was tested within the entire cohort and in the subgroup of CS patients with cardiac arrest at admission. The final study cohort comprised 248 patients. Patients with RBBB showed the highest 30-day all-cause mortality followed by LBBB and no BBB (72.5% vs. 52.9% vs. 50.0%; log-rank p = 0.015). These findings were consistent even after solely including CS patients with cardiac arrest (90.0% vs. 73.3% vs. 62.2%; log-rank p = 0.008). After adjustment for lactate, norepinephrine, troponin I, Acute Physiology Score, Society of Cardiovascular Angiography & Interventions shock stage, and heart rate in a multivariable Cox regression analysis, RBBB still revealed a negative impact on 30-day all-cause mortality (hazard ratio [HR], 1.807; 95% CI, 1.107-2.947; p = 0.018), whereas LBBB was not associated with 30-day all-cause mortality. In this multivariable Cox regression model lactate (HR, 1.065; 95% CI, 1.018-1.115; p = 0.006), troponin I (HR, 1.003; 95% CI, 1.001-1.005; p = 0.001), and Acute Physiology Score (HR, 1.033; 95% CI, 1.001-1.066; p = 0.041) were as well associated with 30-day all-cause mortality. Finally, no association of RBBB was found with the incidence of liver or severe renal failure.

CONCLUSIONS

Besides the Acute Physiology Score, lactate, and troponin levels, RBBB was associated with an increased 30-day all-cause mortality in consecutive CS patients with and without cardiac arrest, whereas LBBB showed no prognostic impact.

Electrocardiographic patterns and clinical outcomes of acute coronary syndrome cardiogenic shock in patients undergoing percutaneous coronary intervention - A propensity score analysis

OBJECTIVES

To determine the influence of presenting electrocardiographic (ECG) changes on prognosis in acute coronary syndrome cardiogenic shock (ACS-CS) patients undergoing percutaneous coronary angiography (PCI).

BACKGROUND

The effect of initial ECG changes such as ST-elevation myocardial infarction (STEMI) versus non-STEMI among patients ACS-CS on prognosis remains unclear.

METHODS

We analysed data from consecutive patients with ACS-CS enrolled in the Victorian Cardiac Outcomes registry between 2014 and 2020. Inverse probability of treatment weighting analysis (IPTW) was used to assess the effect of ECG changes on 30-day mortality.

RESULTS

Of 1564 patients with ACS-CS who underwent PCI, 161 had non-STEMI and 1403 had STEMI on ECG. The mean age was 66 ± 13 years, and 74 % (1152) were males. Patients with non-STEMI compared to STEMI were older (70 ± 12 vs 65 ± 13 years), had higher rates of diabetes (34 % vs 21 %), prior coronary artery bypass graft surgery (14 % vs 3.3 %), peripheral arterial disease (10.6 % vs 4.1 %, p < 0.01), and lower baseline eGFR (53.8 [37.1, 75.4] vs 65.3 [46.3, 87.8] ml/min/1.73m2), all p ≤ 0.01. Non-STEMI patients were more likely to have a culprit left circumflex artery (29 % vs 20 %) and more often underwent multivessel percutaneous coronary intervention (30 % vs 20 %) but had lower rates of out-of-hospital cardiac arrest (21 % vs 39 %), all p ≤ 0.01. Propensity score analysis with IPTW confirmed that non-STEMI ECG was associated with lower odds for 30-day all-cause mortality (OR 0.47 [0.32, 0.69], p < 0.001), and 30-day major adverse cardiovascular and cerebrovascular events (OR 0.48 [0.33, 0.70]).

CONCLUSIONS

In patients undergoing PCI, Non-STEMI as compared to STEMI on index ECG was associated with approximately half the relative risk of both 30-day mortality and 30-day MACCE and could be a useful variable to integrate in ACS-CS risk scores.

COX6B1 relieves hypoxia/reoxygenation injury of neonatal rat cardiomyocytes by regulating mitochondrial function

Objective

Mitochondrial dysfunction plays a pivotal role in various pathophysiological processes of heart. Cytochrome oxidase subunit 6B1 (COX6B1) is a subunit of cytochrome oxidase.

Methods

Cardiomyocytes were isolated from neonatal SD rats (within 24 h of birth) by repeating digestion of collagenase and trypsin. COX6B1 over-expression and hypoxia/reoxygenation was conducted on neonatal rat cardiomyocytes. Cell viability, apoptosis rates, mitochondria membrane potential and mitochondrial permeabilization transition pores (mPTPs) were then determined respectively by Cell performing Counting Kit-8 (CCK-8), Annexin-V/PI assay, JC-1 assay, mPTP assay. The expression of cyto C and apoptosis-related factors were detected by RT-Qpcr and Western blot.

Results

Hypoxia/reoxygenation increased apoptosis and mPTP levels, and decreased mitochondria membrane potential in I/R and I/R + EV groups. COX6B1 over-expression increased mitochondria cyto C, pro-caspase-3, pro-caspase-9 and bcl-2, while it decreased cytosol cyto C, cleaved-caspase-3, cleaved-caspase-9 and bax compared to I/R + EV group.

Conclusion

COX6B1 protected cardiomyocytes from hypoxia/reoxygenation injury by reducing ROS production and cell apoptosis, during which reduction of the release of cytochrome C from mitochondria to cytosol was involved. Our study demonstrated that COX6B1 may be an candidate target gene in preventing hypoxia/reoxygenation injury of cardiomyocytes.

Prevalence, Temporal Evolution, and Impact on Survival of Ventricular Conduction Blocks in Patients With Acute Coronary Syndrome and Cardiogenic Shock

Changes in QRS duration and pattern are regarded to reflect severe ischemia in acute coronary syndromes (ACS), and ventricular conduction blocks (VCBs) are recognized high-risk markers in both ACS and acute heart failure. Our aim was to evaluate the prevalence, temporal evolution, association with clinical and angiographic parameters, and impact on mortality of VCBs in ACS-related cardiogenic shock (CS). Data of 199 patients with ACS-related CS from a prospective multinational cohort were evaluated with electrocardiogram data from baseline and day 3. VCBs including left or right bundle branch block, right bundle branch block and hemiblock, isolated hemiblocks, and unspecified intraventricular conduction delay were assessed. Fifty percent of patients had a VCB at baseline; these patients were older, had poorer left ventricular function and had more often left main disease compared with those without VCB. One-year mortality was over 2-fold in patients with VCB compared with those without VCB (68% vs 32%, p<0.001). All types of VCBs at baseline were associated with increased mortality, and the predictive value of a VCB was independent of baseline variables and coronary angiography findings. Interestingly, 37% of the VCBs were transient, i.e., disappeared before day 3. However, 1-year mortality was much higher in these patients (69%) compared to patients with persistent (38%) or no VCB (15%, p<0.001). Indeed, a transient VCB was a strong independent predictor of 1-year mortality. In conclusion, our findings propose that any VCB in baseline electrocardiogram, even if transient, identifies very early patients at particularly high mortality risk in ACS-related CS.

Predictive value of the baseline electrocardiogram ST-segment pattern in cardiogenic shock: Results from the CardShock Study

BACKGROUND

The most common aetiology of cardiogenic shock (CS) is acute coronary syndrome (ACS), but even up to 20%-50% of CS is caused by other disorders. ST-segment deviations in the electrocardiogram (ECG) have been investigated in patients with ACS-related CS, but not in those with other CS aetiologies. We set out to explore the prevalence of different ST-segment patterns and their associations with the CS aetiology, clinical findings and 90-day mortality.

METHODS

We analysed the baseline ECG of 196 patients who were included in a multinational prospective study of CS. The patients were divided into 3 groups: (a) ST-segment elevation (STE). (b) ST-segment depression (STDEP). (c) No ST-segment deviation or ST-segment impossible to analyse (NSTD). A subgroup analysis of the ACS patients was conducted.

RESULTS

ST-segment deviations were present in 80% of the patients: 52% had STE and 29% had STDEP. STE was associated with the ACS aetiology, but one-fourth of the STDEP patients had aetiology other than ACS. The overall 90-day mortality was 41%: in STE 47%, STDEP 36% and NSTD 33%. In the multivariate mortality analysis, only STE predicted mortality (HR 1.74, CI₉₅ 1.07-2.84). In the ACS subgroup, the patients were equally effectively revascularized, and no differences in the survival were noted between the study groups.

CONCLUSION

ST-segment elevation is associated with the ACS aetiology and high mortality in the unselected CS population. If STE is not present, other aetiologies must be considered. When effectively revascularized, the prognosis is similar regardless of the ST-segment pattern in ACS-related CS.

Clinical Characteristics, Management, and Outcomes of Acute Coronary Syndrome in Patients With Right Bundle Branch Block on Presentation

We examined the relations between right bundle branch block (RBBB) and clinical characteristics, management, and outcomes among a broad spectrum of patients with acute coronary syndrome (ACS). Admission electrocardiograms of patients enrolled in the Global Registry of Acute Coronary Events (GRACE) electrocardiogram substudy and the Canadian ACS Registry I were analyzed independently at a blinded core laboratory. We performed multivariable logistic regression analysis to assess the independent prognostic significance of admission RBBB on in-hospital and 6-month mortality. Of 11,830 eligible patients with ACS (mean age 65; 66% non-ST-elevation ACS), 5% had RBBB. RBBB on admission was associated with older age, male sex, more cardiovascular risk factors, worse Killip class, and higher GRACE risk score (all p <0.01). Patients with RBBB less frequently received in-hospital cardiac catheterization, coronary revascularization, or reperfusion therapy (all p <0.05). The RBBB group had higher unadjusted in-hospital (8.8% vs 3.8%, p <0.001) and 6-month mortality rates (15.1% vs 7.6%, p <0.001). After adjusting for established prognostic factors in the GRACE risk score, RBBB was a significant independent predictor of in-hospital death (odds ratio 1.45, 95% CI 1.02 to 2.07, p = 0.039), but not cumulative 6-month mortality (odds ratio 1.29, 95% CI 0.95 to 1.74, p = 0.098). There was no significant interaction between RBBB and the type of ACS for either in-hospital or 6-month mortality (both p >0.50). In conclusion, across a spectrum of ACS, RBBB was associated with preexisting cardiovascular disease, high-risk clinical features, fewer cardiac interventions, and worse unadjusted outcomes. After adjusting for components of the GRACE risk score, RBBB was a significant independent predictor of early mortality.