Intravenous beta-blockers in ST-segment elevation myocardial infarction: A systematic review and meta-analysis

Role of β-blockers in the cardiovascular disease continuum: a collaborative Delphi survey-based consensus from Asia-Pacific

OBJECTIVE

This Delphi method of consensus was designed to develop scientific statements for β-blockers in the continuum of cardiovascular diseases with a special focus on the role of bisoprolol.

METHODS

Eleven experienced cardiologists from across the Asia-Pacific countries participated in two rounds of the survey. In the first round, experts were asked to rate agreement/disagreement with 35 statements across seven domains regarding the use of β-blockers for treating hypertension, heart failure, coronary artery diseases, co-morbidities, as well as their safety profile, usage pattern, and pharmacokinetic variability. A consensus for a statement could be reached with >70% agreement.

RESULTS

Except for seven statements, all attained consensus in the first round. In the second round that was conducted virtually, the experts re-appraised their ratings for the seven statements along with a critical appraisal of two additional statements that were suggested by experts in the preceding round. At the end of the second round, the final version included 36 statements (34 original statements, two statements suggested by experts, and the omission of one statement that did not attain consensus). The final version of statements in the second round was disseminated among experts for their approval followed by manuscript development.

CONCLUSION

Attainment of consensus for almost all statements reconfirms the clinical benefits of β-blockers, particularly β1-selective blockers for the entire spectrum of cardiovascular diseases.

Heart rate and heart rate variability as a prognosticating feature for functional outcome after cardiac arrest: A scoping review

Background

Despite significant progress in cardiopulmonary resuscitation and post-cardiac arrest care, favorable outcome in out-of hospital sudden cardiac arrest patients remains low. One of the main reasons for mortality in these patients is withdrawal of life-sustaining treatment. There is a need for precise and equitable prognostication tools to support families in avoiding premature or inappropriate WLST. Heart rate (HR) and heart rate variability (HRV) have been noted for their association with outcome, and are positioned to be a useful modality for prognostication.

Objectives

The aim of this scoping review is to rigorously explore which electrocardiography features have been shown to predict functional outcome in post-cardiac arrest patients.

Methods

The search was performed in Pubmed, EMBASE, and SCOPUS for studies published from January 1, 2011, to September 29, 2022, including papers in English or Korean.

Results

Seven studies were included with a total of 1359 patients. Four studies evaluated HR, one study evaluated RR inverval, and two studies evaluated HRV. All studies were retrospective, with 3 multi-center and 4 single-center studies. All seven studies were inclusive of patients who underwent targeted temperature management (TTM) after cardiac arrest, and two studies included patients without TTM. Five studies used cerebral performance category to assess functional outcome, two studies used Glasgow outcome score, and one study used modified Rankin scale. Three studies measured outcome at hospital discharge, one study measured outcome at 14 days after return of spontaneous circulation, two studies measured outcome after 3 months, and one after 1 year. In all studies that evaluated HR, lower HR was associated with favorable functional outcome. Two studies found that higher complexity of HRV was associated with favorable functional outcome.

Conclusion

HR and HRV showed clear associations with functional outcome in patients after CA, but cinilcial utility for prognostication is uncertain.

Clinical Efficacy and Safety of Early Intravenous Administration of Beta-Blockers in Patients Suffering from Acute ST-Segment Elevation Myocardial Infarction Without Heart Failure Undergoing Primary Percutaneous Coronary Intervention: A Study-Level Meta-Analysis of Randomized Clinical Trials

BACKGROUND

Several clinical studies have produced diverse results regarding the efficacy and safety of early intravenous beta-blockers in patients with acute ST-segment elevation myocardial infarction (STEMI). A study-level meta-analysis of randomized clinical trials (RCTs) comparing early intravenous beta-blockers versus placebo or routine care in STEMI patients undergoing primary percutaneous coronary intervention (PCI) was performed.

METHODS

A database search was conducted using PubMed, EMBASE, the Cochrane Library, and Clinicaltrials.gov for randomized clinical trials (RCTs) that compared intravenous beta-blockers versus placebo or routine care in STEMI patients who underwent primary PCI. The efficacy outcomes were infarct size (IS, % of LV) and the myocardial salvage index (MSI) based on magnetic resonance imaging, electrocardiographic findings, heart rate, ST-segment reduction percent (STR%), and complete STR. Safety outcomes included arrhythmias in the first 24 h (ventricular tachycardia and fibrillation [VT/VF], atrial fibrillation [AF], bradycardia, and advanced atrioventricular [AV] block), cardiogenic shock and hypotension during hospitalization, left ventricular ejection fraction (LVEF), and major adverse cardiovascular events (cardiac death, stroke, reinfarction, and heart failure readmission) at follow-up.

RESULTS

Seven RCTs with 1428 patients were included in this study, with 709 patients in the intravenous beta-blockers and 719 in the control group. Intravenous beta-blockers improved MSI compared to the control group (weighted mean difference [WMD] 8.46, 95% confidence interval [CI] 3.12-13.80, P = 0.002, I² = 0%), but no differences were observed in IS (% of LV) between groups. Compared to the control group, the intravenous beta-blockers group had a lower risk of VT/VF (relative risk [RR] 0.65, 95% CI 0.45-0.94, P = 0.02, I² = 35%) without an increase of AF, bradycardia, and AV-block and significantly decreased HR, hypotension. LVEF at 1 week ± 7 days (WMD 2.06, 95% CI 0.25-3.88, P = 0.03, I² = 12%) and 6 months ± 7 days (WMD 3.24, 95% CI 1.54-4.95, P = 0.0002, I² = 0%) was improved in the intravenous beta-blockers group compared to the control group. Subgroup analysis showed that intravenous beta-blockers before PCI decreased the risk of VT/VF and improved LVEF compared to the control group. Furthermore, sensitivity analysis showed that patients with a left anterior descending (LAD) artery lesion had a smaller IS (% of LV) in the intravenous beta-blockers group compared to the control group.

CONCLUSION

Intravenous beta-blockers improved the MSI, decreased the risk of VT/VF in the first 24 h, and were associated with increased LVEF at 1 week and 6 months following PCI. In particular, intravenous beta-blockers started before PCI is beneficial for patients with LAD lesions.

Beta-Blocker Use after Discharge in Patients with Acute Myocardial Infarction in the Contemporary Reperfusion Era

Background and objectives: The effect of beta-blocker use after discharge on patients with acute myocardial infarction (AMI) in the contemporary reperfusion era remains ambiguous. By applying meta-analysis, we sought to assess the role of beta-blockers in the contemporary reperfusion era. Materials and Methods: Randomized controlled trials (RCT) and observational studies using propensity score matching, comparing use of beta-blockers with non-use of beta-blockers, in patients with AMI after discharge. The primary outcome was all-cause mortality. Odds ratios (OR) and associated 95% confidence intervals (CI) were calculated. Results: One RCT and eight observational studies, containing 47,339 patients with AMI, were included. Compared with non-use of beta-blockers, beta-blocker use after discharge may have reduced the risk of all-cause mortality (OR: 0.70, 95% CI: 0.61 to 0.80, I² = 14.4%), cardiac death (OR: 0.63, 95% CI: 0.44 to 0.91, I² = 22.8%), myocardial infarction (OR: 0.73, 95% CI: 0.62 to 0.86, I² = 0), and revascularization (OR: 0.92, 95% CI: 0.85 to 0.99, I² = 0). No significant differences were found in major adverse cardiovascular events (MACE, OR: 0.88, 95% CI: 0.66 to 1.17, I² = 78.4%), heart failure (OR: 0.56, 95% CI: 0.29 to 1.08, I² = 0) or stroke (OR: 1.13, 95% CI: 0.92 to 1.39, I² = 0). For patients with preserved left ventricular function, beta-blocker use after discharge may have also reduced the risk of all-cause mortality (OR: 0.61, 95% CI: 0.44 to 0.84, I² = 0). Conclusions: Use of beta-blockers after discharge may still be beneficial for AMI patients in the contemporary reperfusion era, with or without preserved left ventricular function.

Beneficial Effects of Ivabradine on Post-Resuscitation Myocardial Dysfunction in a Porcine Model of Cardiac Arrest

Background:

Ivabradine selectively inhibits the If current, reducing the heart rate and protecting against myocardial ischemia/reperfusion injury. We investigated the effects of ivabradine on post-resuscitation myocardial function in a porcine model of cardiopulmonary resuscitation.

Methods and Results:

Ventricular fibrillation was induced and untreated for 8 min while defibrillation was attempted after 6 min of cardiopulmonary resuscitation in anesthetized domestic swine. Then the animals were randomized into ivabradine and placebo groups (n = 5 each). Ivabradine and saline were administered at the same volume 5 min after Return of Spontaneous Circulation, followed by continuous intravenous infusion at 0.5 mg/kg for 480 min. Hemodynamic parameters were continuously recorded. Myocardial function was assessed by echocardiography at baseline and at 60, 120, 240, 480 min and 24 h after resuscitation. The serum levels of N-terminal pro-brain natriuretic peptide (NT-proBNP) and cardiac troponin I (cTnI) were measured by commercial enzyme-linked immunosorbent assay kits. Animals were killed 24 h after resuscitation, and all myocardial tissue was removed for histopathological analysis. The heart rate was significantly reduced from 1 h after resuscitation in the ivabradine group (all P < 0.05). The post-resuscitation mitral E/A and E/e′ velocity ratios and left ventricular ejection fraction were significantly better in the ivabradine than placebo group (P < 0.05). The serum levels of myocardial injury biomarkers (NT-proBNP, cTnI) and the myocardial biopsy scores were significantly lower in the ivabradine than placebo group (P < 0.05). Neurological deficit scores were lower in the IVA group at PR 24 h (P < 0.05).

Conclusions:

Ivabradine improved post-resuscitation myocardial dysfunction, myocardial injury, and post-resuscitation cerebral function, and also slowed the heart rate in this porcine model.

2020 Korean Society of Myocardial Infarction Expert Consensus Document on Pharmacotherapy for Acute Myocardial Infarction

Clinical practice guidelines published by the European Society of Cardiology and the American College of Cardiology/American Heart Association summarize the available evidence and provide recommendations for health professionals to enable appropriate clinical decisions and improve clinical outcomes for patients with acute myocardial infarction (AMI). However, most current guidelines are based on studies in non-Asian populations in the pre-percutaneous coronary intervention (PCI) era. The Korea Acute Myocardial Infarction Registry is the first nationwide registry to document many aspects of AMI from baseline characteristics to treatment strategies. There are well-organized ongoing and published randomized control trials especially for antiplatelet therapy among Korean patients with AMI. Here, members of the Task Force of the Korean Society of Myocardial Infarction review recent published studies during the current PCI era, and have summarized the expert consensus for the pharmacotherapy of AMI.