Beta-blockers and Short-Term Cardiovascular Outcomes In Patients Hospitalized For Acute Coronary Syndrome and a Left Ventricular Ejection Fraction ≥40

The Long-Term Prognostic Role of Nighttime Resting Heart Rate in Obstructive Sleep Apnea in Patients with Acute Coronary Syndrome

AIM

A close relationship exists between resting heart rate (RHR) and obstructive sleep apnea (OSA). Still, the prognostic importance of nighttime RHR in patients with acute coronary syndrome (ACS) with or without OSA remains unclear.

METHODS

In this prospective cohort study, OSA was defined as an apnea-hypopnea index of ≥ 15 events/h, and the high nighttime RHR (HNRHR) was defined as a heart rate of ≥ 70 bpm. The primary endpoint was a major adverse cardiovascular and cerebrovascular event (MACCE), including cardiovascular death, myocardial infarction, stroke, ischemia-driven revascularization, or hospitalization for heart failure.

RESULTS

Among the 1875 enrolled patients, the mean patient age was 56.3±10.5 years, 978 (52.2%) had OSA, and 425 (22.7%) were in HNRHR. The proportion of patients with HNRHR is higher in the OSA population than in the non-OSA population (26.5% vs. 18.5%; P＜0.001). During 2.9 (1.5, 3.5) years of follow-up, HNRHR was associated with an increased risk of MACCE in patients with OSA (adjusted HR: 1.56, 95% CI: 1.09-2.23, P=0.014), but not in patients without OSA (adjust HR: 1.13, 95% CI: 0.69-1.84, P=0.63).

CONCLUSIONS

In patients with ACS, a nighttime RHR of ≥ 70 bpm was associated with a higher risk of MACCE in those with OSA but not in those without it. This identifies a potential high-risk subgroup where heart rate may interact with the prognosis of OSA. Further research is needed to determine causative relationships and confirm whether heart rate control impacts cardiovascular outcomes in patients with ACS-OSA.

The Effect of Beta-Blocker Post-Myocardial Infarction With Ejection Fraction >40% Pooled Analysis From Seven Arabian Gulf Acute Coronary Syndrome Registries

The use of beta-blockers (BB) in reduced left ventricular ejection fraction (LVEF) post-myocardial infarction (MI) is associated with reduced 1-year mortality, while their role in patients with mid-range and preserved LVEF post-MI remains controversial. We studied 31,620 patients who presented with acute coronary syndrome (ACS) enrolled in seven Arabian Gulf registries between 2005 and 2017. Patients with LVEF ≤40% were excluded. The remaining cohort was divided into two groups: BB group (n = 15,541) and non-BB group (n = 2,798), based on discharge medications. Patients in the non-BB group were relatively younger (55.3 vs. 57.4, P = .004) but higher risk at presentation; with higher Global Registry of Acute Coronary Events (GRACE) score (119.2 vs 109.2, P < .001), higher percentage of cardiogenic shock (3.5 vs 1.4%, P < .001), despite lower prevalence of comorbidities, such as hypertension and hyperlipidemia. BB use was associated with lower 1-year mortality in a multivariate logistic regression analysis, adjusting for major confounders [adjusted odds ratio (OR): 0.71 (95% CI 0.51-0.99)]. This remained the case in a sensitivity analysis using propensity score matching [adjusted OR: 0.34 (95% CI 0.16-0.73)]. In this study, using Arabian Gulf countries registries, the use of BB after ACS with LVEF >40% was independently associated with lower 1-year mortality.