Use of beta-blockers in congestive heart failure

Treatment optimization of beta-blockers in chronic heart failure therapy

Although evidence based guidelines recommend optimal use of beta blockers in all patients with chronic heart failure unless contraindicated, they are often underutilized and/or prescribed below the recommended dosage in the majority of patients with heart failure. To our knowledge, however, the optimal use of beta-blockers in chronic heart failure is not investigated in Ethiopia. Therefore, the aim of our study was to investigate the utilization and optimization of beta blockers in the management of patients with chronic heart failure in Ethiopia. A prospective observational study was conducted among ambulatory patients with chronic heart failure in Ethiopia. We included adult patients with a diagnosis of heart failure with a baseline left ventricular ejection fraction < 40% who had been on follow-up for at least 6 months. Patients were recruited into the study during their appointment for medication refilling using simple random sampling technique. All patients were followed for at least 6 months to determine the optimal use of beta blockers. The optimal use of beta blockers was determined according to evidence based guidelines. After explaining the purpose of the study, we obtained written informed consent from all participants. Data were collected through patient interview and review of patients' medical records. Binary logistic regression analysis was performed to identify factors associated with utilization of beta blockers. A total of 288 patients were included in the study. Out of the total, 67% of the patients were receiving beta blockers. Among the patients who received beta blockers, 34.2% were taking guideline recommended beta blockers while 65.8% were taking atenolol, which is not guideline recommended beta blocker. Among the patients who received guideline recommended beta blockers, only 3% were taking optimal dose. Prior hospitalization [Adjusted Odds ratio (AOR) 0.38, 95% confidence interval (CI) 0.19-0.76], dose of furosemide > 40 mg (AOR 0.39, 95% CI 0.20-0.76), ischemic heart disease (AOR 3.27, 95% CI 1.66-6.45), atrial fibrillation (AOR 4.41, 95% CI 1.38-14.13) were significantly associated with the utilization of beta-blockers. Despite proven benefit, beta blockers were not optimally used in most of the participants in this study. The presence of ischemic heart disease and atrial fibrillation were positively associated with the utilization of beta blockers while hospitalization and higher diuretic dose were negatively associated with the utilization of beta blockers. Clinicians should attempt to use evidence based beta blockers at guideline recommended target doses that have been shown to have morbidity and mortality benefit in chronic heart failure. Moreover, more effort needs to be done to minimize the potentially modifiable risk factors for underutilization of beta blocker in chronic heart failure therapy.

Sex-related differences in chronic heart failure

The prevalence of chronic heart failure (CHF) is steadily increasing. Both sexes are affected, with significant differences in etiology, epidemiology and clinical presentation, prognosis, comorbidities, and response to treatment. Women tend to develop CHF at a more advanced age, present more often with HF with preserved ejection fraction, are more symptomatic, and have a worse quality of life than men, but also a better prognosis. In women, CHF has more frequently a non-ischemic etiology, and arterial hypertension and diabetes mellitus are leading comorbidities. Furthermore, many sex-related differences have been detected in the response to treatment, for example a greater prognostic benefit from angiotensin-receptor blockers in women, a higher incidence of complications after defibrillator implantation, and a greater response to cardiac resynchronization therapy. Furthermore, women are less likely to receive defibrillator therapy or heart transplantation. The significant underrepresentation of women in clinical trials limits our capacity to evaluate the extent of sex-related differences in CHF, although their characterization seems crucial in order to achieve the ultimate goal of a tailored therapy for this condition.

Ryanodine receptor dysfunction in human disorders

Regulation of intracellular calcium (Ca²⁺) is critical in all cell types. The ryanodine receptor (RyR), an intracellular Ca²⁺ release channel located on the sarco/endoplasmic reticulum (SR/ER), releases Ca²⁺ from intracellular stores to activate critical functions including muscle contraction and neurotransmitter release. Dysfunctional RyR-mediated Ca²⁺ handling has been implicated in the pathogenesis of inherited and non-inherited conditions including heart failure, cardiac arrhythmias, skeletal myopathies, diabetes, and neurodegenerative diseases. Here we have reviewed the evidence linking human disorders to RyR dysfunction and describe novel approaches to RyR-targeted therapeutics.

Randomised feasibility trial into the effects of low-frequency electrical muscle stimulation in advanced heart failure patients

OBJECTIVES

Low-frequency electrical muscle stimulation (LF-EMS) may have the potential to reduce breathlessness and increase exercise capacity in the chronic heart failure population who struggle to adhere to conventional exercise. The study's aim was to establish if a randomised controlled trial of LF-EMS was feasible.

DESIGN AND SETTING

Double blind (participants, outcome assessors), randomised study in a secondary care outpatient cardiac rehabilitation programme.

PARTICIPANTS

Patients with severe heart failure (New York Heart Association class III-IV) having left ventricular ejection fraction <40% documented by echocardiography were eligible.

INTERVENTIONS

Participants were randomised (remotely by computer) to 8 weeks (5×60 mins per week) of either LF-EMS intervention (4 Hz, continuous, n=30) or sham placebo (skin level stimulation only, n=30) of the quadriceps and hamstrings muscles. Participants used the LF-EMS straps at home and were supervised weekly OUTCOME MEASURES: Recruitment, adherence and tolerability to the intervention were measured during the trial as well as physiological outcomes (primary outcome: 6 min walk, secondary outcomes: quadriceps strength, quality of life and physical activity).

RESULTS

Sixty of 171 eligible participants (35.08%) were recruited to the trial. 12 (20%) of the 60 patients (4 LF-EMS and 8 sham) withdrew. Forty-one patients (68.3%), adhered to the protocol for at least 70% of the sessions. The physiological measures indicated no significant differences between groups in 6 min walk distance(p=0.13) and quality of life (p=0.55) although both outcomes improved more with LF-EMS.

CONCLUSION

Patients with severe heart failure can be recruited to and tolerate LF-EMS studies. A larger randomised controlled trial (RCT) in the advanced heart failure population is technically feasible, although adherence to follow-up would be challenging. The preliminary improvements in exercise capacity and quality of life were minimal and this should be considered if planning a larger trial.

TRIAL REGISTRATION NUMBER

ISRCTN16749049.

Reversal of subcellular remodelling by losartan in heart failure due to myocardial infarction

This study tested the reversal of subcellular remodelling in heart failure due to myocardial infarction (MI) upon treatment with losartan, an angiotensin II receptor antagonist. Twelve weeks after inducing MI, rats were treated with or without losartan (20 mg/kg; daily) for 8 weeks and assessed for cardiac function, cardiac remodelling, subcellular alterations and plasma catecholamines. Cardiac hypertrophy and lung congestion in 20 weeks MI-induced heart failure were associated with increases in plasma catecholamine levels. Haemodynamic examination revealed depressed cardiac function, whereas echocardiographic analysis showed impaired cardiac performance and marked increases in left ventricle wall thickness and chamber dilatation at 20 weeks of inducing MI. These changes in cardiac function, cardiac remodelling and plasma dopamine levels in heart failure were partially or fully reversed by losartan. Sarcoplasmic reticular (SR) Ca²⁺-pump activity and protein expression, protein and gene expression for phospholamban, as well as myofibrillar (MF) Ca²⁺-stimulated ATPase activity and α-myosin heavy chain mRNA levels were depressed, whereas β-myosin heavy chain expression was increased in failing hearts; these alterations were partially reversed by losartan. Although SR Ca²⁺-release activity and mRNA levels for SR Ca²⁺-pump were decreased in failing heart, these changes were not reversed upon losartan treatment; no changes in mRNA levels for SR Ca²⁺-release channels were observed in untreated or treated heart failure. These results suggest that the partial improvement of cardiac performance in heart failure due to MI by losartan treatment is associated with partial reversal of cardiac remodelling as well as partial recovery of SR and MF functions.

Treatment of hypertension in heart failure with preserved ejection fraction: role of the kidney

Heart failure can present clinically as primarily diastolic or systolic dysfunction or both. There is an increasing awareness that heart failure can occur in the presence of a normal left ventricular ejection fraction. Heart failure with normal left ventricular ejection fraction is frequently referred to as diastolic heart failure because of the presence of diastolic left ventricular dysfunction evident from impaired left ventricular relaxation. This article focuses on the treatment of hypertension and the role the kidney plays in selecting appropriate agents.

Chronic administration of carvedilol improves cardiac function in 6-month-old Syrian cardiomyopathic hamsters

Heart failure (HF) is a multifactorial and progressive disease that has been linked to activation of the renin-angiotensin and sympathetic systems. In recent years, beta-blockers have been shown to improve the status of HF patients, although the precise mechanisms remain unclear. The present study evaluates the effect of beta-blockade with carvedilol (1 mg/kg/day) on cardiovascular function in 2- and 6-month-old cardiomyopathic hamsters (SCH) after 1-month and 5-month treatment periods with the drug, respectively. Age-matched golden hamsters were used as controls (CT). Systolic blood pressure (SBP) and echocardiographic studies were evaluated. The latter studies included left ventricular end-systolic (LVESV) and end-diastolic (LVEDV) volumes, ejection fraction (EF), cardiac output index (COI), heart rate (HR), and left ventricular posterior wall thickness (LVPWT). In 2-month-old SCH, carvedilol administration during a 1-month period reduced SBP from 107.59 +/- 3.49 to 77.26 +/- 3.49 mm Hg (n = 5, p < 0.05). At this stage, cardiac parameters in SCH were similar to those of controls and were not affected by carvedilol administration. In 6-month-old SCH, 5-month administration of carvedilol decreased SBP from 102.16 +/- 3.61 to 90.60 +/- 2.80 mm Hg (n = 5, p < 0.05), HR from 363 +/- 14 to 324 +/- 14 bpm (n = 5, p < 0.05), and LVESV from 0.18 +/- 0.01 to 0.13 +/- 0.01 ml/100 g BW (n = 5, p < 0.05), and increased EF and COI by 14 and 23%, respectively (n = 5, p < 0.05). The drug did not modify LVEDV or LVPWT. These results reveal that carvedilol significantly improves cardiac function in 6-month-old cardiomyopathic hamsters, but it does not prevent ventricular dilatation. Improved cardiac function appears to be secondary to decreased total peripheral resistance, due mainly to the vasodilator properties of the drug. Thus, overactivation of the sympathetic system is not likely to be a determining factor in the etiology of dilated cardiomyopathy in this animal model.

Bisoprolol Improves Echocardiographic Parameters of Left Ventricular Diastolic Function in Patients with Systemic Hypertension

Left ventricular (LV) diastolic dysfunction (LVD) is a common complication secondary to hypertension. It has been reported that bisoprolol is effective in reducing blood pressure and has beneficial cardiac effects in patients with hypertension. However, its effect on LV diastolic function has not been studied in detail. In this study, we sought to determine bisoprolol's effect on left ventricle diastolic function. Data from 25 patients were statistically analyzed. Peaks E and A wave, E/A ratio, isovolumetric relaxation time and E wave deceleration time were measured echocardiographically. Doppler echocardiography measurements after bisoprolol treatment revealed an improvement in LV diastolic function. In conclusion, our results show that treatment with bisoprolol, improves echocardiographic parameters of LV diastolic function after 3 months of treatment.

New developments in the use of β-blockers for the management of heart failure

Chronic heart failure (HF) has become a significant healthcare problem in the US. The number of new cases per year continues to grow steadily due to an ageing population and improved survival from acute coronary syndromes. As a consequence, the management of HF patients is of great importance. Effective management of HF includes stabilising the patient and improving the clinical symptoms associated with HF. Patients with HF have increased sympathetic nervous system activity that contributes to impaired cardiovascular function over time and subsequently results in death. beta-blockers prevent such impairment through inhibition of the sympathetic nervous system neurohormonal pathway. Numerous clinical trials conducted over the past decade have demonstrated that beta-blockers, in conjunction with angiotensin-converting enzyme inhibitors, are not only effective but are superior to other medical interventions for the treatment of HF. The standard of care for patients with HF now includes beta-blockers as well as ACE inhibitors.

A distinct role for norepinephrine in memory retrieval

A role for norepinephrine in learning and memory has been elusive and controversial. A longstanding hypothesis states that the adrenergic nervous system mediates enhanced memory consolidation of emotional events. We tested this hypothesis in several learning tasks using mutant mice conditionally lacking norepinephrine and epinephrine, as well as control mice and rats treated with adrenergic receptor agonists and antagonists. We find that adrenergic signaling is critical for the retrieval of intermediate-term contextual and spatial memories, but is not necessary for the retrieval or consolidation of emotional memories in general. The role of norepinephrine in retrieval requires signaling through the beta(1)-adrenergic receptor in the hippocampus. The results demonstrate that mechanisms of memory retrieval can vary over time and can be different from those required for acquisition or consolidation. These findings may be relevant to symptoms in several neuropsychiatric disorders as well as the treatment of cardiac failure with beta blockers.