How does beta (beta blocker) blockade improve heart failure hemodynamics?

From the Guidelines

Beta blockade is a crucial treatment for heart failure that improves hemodynamics by reducing the risk of death and hospitalization, and should be initiated at low doses and titrated upward as tolerated, as evidenced by the 2022 AHA/ACC/HFSA guideline 1. Beta blockers work by blocking the harmful effects of chronic sympathetic nervous system activation, which initially may temporarily reduce cardiac output, but with continued use, they improve heart function through several mechanisms, including reducing heart rate, allowing more time for ventricular filling and coronary perfusion, decreasing myocardial oxygen demand, reducing harmful ventricular remodeling, and improving left ventricular ejection fraction over time 1. Some key benefits of beta blockers in heart failure management include:

• Reducing the risk of death and the combined risk of death or hospitalization in patients with HFrEF 1
• Improving LVEF, lessening the symptoms of HF, and improving clinical status 1
• Working synergistically with ACE inhibitors and other heart failure medications to optimize hemodynamics and reverse the neurohormonal cascade that drives heart failure progression 1
• Being effective in patients with or without CAD, and in patients with or without diabetes, older patients, as well as in women and across racial and ethnic groups, although not in patients with AF 1 Treatment with beta blockers should be maintained long-term to reduce the risk of major cardiovascular events, even if symptoms do not improve, and every effort should be made to achieve the target doses of the beta blockers shown to be effective in major clinical trials, as tolerated 1.

From the FDA Drug Label

The main reasons for not receiving the target beta-blocker doses at baseline were hypotension (45% of patients not at target), fatigue (32%), dyspnea (14%), dizziness (12%), history of cardiac decompensation (9%), and bradycardia (6%). Most patients (89%) were taking beta-blockers, with 26% on guideline-defined target daily doses Ivabradine benefit on the primary endpoint in SHIFT appeared to decrease as the dose of beta-blockers increased, with little if any benefit demonstrated in patients taking guideline-defined target doses of beta-blockers.

The mechanism by which beta blockade improves heart failure hemodynamics is not directly stated in the provided text. However, it can be inferred that beta blockers have a beneficial effect on heart failure, as most patients (89%) were taking beta blockers, and the study suggests that ivabradine's benefit decreases as the dose of beta blockers increases.

• Beta blockers likely improve heart failure hemodynamics by reducing the heart's workload and decreasing its oxygen demand, allowing it to function more efficiently.
• The exact mechanism is not explicitly stated in the provided text, and therefore, no definitive conclusion can be drawn about how beta blockade improves heart failure hemodynamics based on this information alone 2.

From the Research

Beta Blocker Mechanism in Heart Failure

• Beta blockers, such as bisoprolol, carvedilol, and metoprolol succinate, have been shown to improve heart failure hemodynamics by reducing morbidity and mortality in patients with heart failure 3, 4, 5, 6, 7.
• The use of these beta blockers can be initiated early, even in stable and symptom-free subjects with heart failure, and should be commenced at small doses and then titrated upward as tolerated to achieve the desired clinical effects on heart rate and symptom control 3.

Clinical Outcomes

• The clinical outcomes of beta blocker use in heart failure include reduced hospitalization, morbidity, mortality, and improved patient satisfaction and quality of life 3, 4, 6.
• Beta blocker use has been associated with a lower risk of heart failure readmission and mortality, but not all-cause readmission, among Medicare beneficiaries hospitalized for heart failure with reduced ejection fraction 6.

Pharmacodynamics and Pharmacokinetics

• The pharmacodynamics and pharmacokinetics of beta blockers, such as metoprolol and carvedilol, have been reviewed, and several issues regarding the design of clinical trials have been identified that could alter the interpretation of the results 4.
• The choice of dose and dosage regimen of beta blockers can affect the clinical outcomes, and clinicians should choose only those agents and dosage forms that have been proven to reduce mortality in heart failure patients 4.

Safety and Tolerability

• Beta blockers have been shown to be safe and tolerable in patients with heart failure, despite concerns about adverse effects 5.
• The use of beta blockers in heart failure has been underutilized, and increasing their use may reduce heart failure-specific readmissions and mortality 6.