Current pharmacotherapeutic strategies for cardiac arrhythmias in heart failure

Do Elderly Patients with Heart Failure and Reduced Ejection Fraction Benefit from Pharmacological Strategies for Prevention of Arrhythmic Events?

BACKGROUND

Heart failure is associated with aging. It is one of the leading causes of morbidity and mortality in Western countries and constitutes the main cause of hospitalization among elderly patients. The pharmacological therapy of patients with heart failure with reduced ejection fraction (HFrEF) has greatly improved during the last years. However, elderly patients less frequently receive recommended medical treatment.

SUMMARY

The quadruple therapy (sacubitril/valsartan, beta-blockers, mineralocorticoid receptor antagonists, and sodium-glucose cotransporter 2 inhibitors) is nowadays the cornerstone of medical treatment since it associates lower risk of heart failure hospitalizations and mortality (also of arrhythmic origin). Cardiac arrhythmias, including sudden cardiac death, are common in patients with HFrEF, entailing worse prognosis. Previous studies addressing the role of blocking the renin-angiotensin-aldosterone system and beta-adrenergic receptors in HFrEF have suggested different beneficial effects on arrhythmia mechanisms. Therefore, the lower mortality associated with the use of the four pillars of HFrEF therapy depends, in part, on lower sudden (mostly arrhythmic) cardiac death.

KEY MESSAGES

In this review, we highlight and assess the role of the four pharmacological groups that constitute the central axis of the medical treatment of patients with HFrEF in clinical prognosis and prevention of arrhythmic events, with special focus on the elderly patient, since evidence supports that most benefits provided are irrespective of age, but elderly patients receive less often guideline-recommended medical treatment.

Effect of sacubitril/valsartan on the occurrence of cardiac arrhythmias and the risk of sudden cardiac death in heart failure: A meta-analysis of randomized controlled trials

Background

Sacubitril/valsartan therapy reduced the risks of death and of hospitalization for heart failure (HF). HF and cardiac arrhythmias have shared physiological mechanisems. Therefore, sacubitril/valsartan may exhibit anti-arrhythmic properties in HF. The purpose of this study was to evaluate the effect of sacubitril/valsartan on the occurrence of cardiac arrhythmias and the risk of sudden cardiac death (SCD) in HF.

Methods

This meta-analysis was performed according to PRISMA guidelines. We searched PubMed and Embase (from inception up to 6 February 2022) to identify randomized control trials (RCTs) on the effect of sacubitril/valsartan on the occurrence of cardiac arrhythmias and the risk of SCD in HF. Primary outcomes were the occurrence of atrial arrhythmias, ventricular arrhythmias, and SCD. Risk ratios (RRs) with 95% confidence intervals (CIs) were pooled using a random-effects model for meta-analysis.

Results

We included 9 RCTs (published between 2012 and 2021) with 18,500 patients (9,244 sacubitril/valsartan vs. 9,256 active control). Enalapril and valsartan were used as active control in six and two studies, respectively. Follow-up ranged from 2 to 35 months. The cumulative occurrence of events was 76, 13, and 48 per 1,000 patient-years for atrial arrhythmias, ventricular arrhythmias and SCD, respectively. There was no significant association between sacubitril/valsartan therapy and the occurrence of atrial arrhythmias (RR 1.06; 95% CI: 0.97–1.17; P = 0.19) and ventricular arrhythmias (RR 0.86; 95% CI 0.68–1.10; P = 0.24). However, sacubitril/valsartan therapy significantly reduced the risk of SCD (RR 0.79; 95% CI 0.70–0.90; P = 0.03) compared with control.

Conclusion

No association between sacubitril/valsartan therapy and the occurrence of atrial and ventricular arrhythmias was found, but sacubitril/valsartan therapy significantly reduced the risk of SCD.

Possible inhibition mechanism of dobutamine hydrochloride as potent inhibitor for human glucose-6-phosphate dehydrogenase enzyme

Glucose-6-phosphate dehydrogenase (G6PD) is the first rate-limiting enzyme in the pentose phosphate pathway. One of the enzyme's most important functions is the production of a reducing agent that is essential for preserving the level of reduced glutathione (GSH). However, some chemicals, such as industrial waste and the active ingredients of several drugs, can cause reduction or blockage in this enzyme's activity. This case causes the occurrence of anemia by damaging erythrocytes. In this study, the G6PD enzyme was purified 21,981 fold with affinity chromatography and the effects of the active ingredients of some antiarrhythmic drugs on enzyme activity were investigated with in vitro and in silico methods. We found that dobutamine hydrochloride significantly decreased enzyme activity and its inhibitory constant (K_i) value was calculated as 19.02 ± 4.83 mM. The in vitro study results also show that dobutamine hydrochloride is a potent inhibitor of enzyme activity. We also found that dobutamine hydrochloride inhibits the hG6PD enzyme's activity by causing structural alterations in substrate and coenzyme binding sites.Communicated by Ramaswamy H. Sarma.