Effect of pimobendan on exercise capacity in patients with heart failure: main results from the Pimobendan in Congestive Heart Failure (PICO) trial

Inotropic Agents: Are We Still in the Middle of Nowhere?

Inotropes are prescribed to enhance myocardial contractility while vasopressors serve to improve vascular tone. Although these medications remain a life-saving therapy in cardiovascular clinical scenarios with hemodynamic impairment, the paucity of evidence on these drugs makes the choice of the most appropriate vasoactive agent challenging. As such, deep knowledge of their pharmacological and hemodynamic effects becomes crucial to optimizing hemodynamic profile while reducing the potential adverse effects. Given this perspective, it is imperative for cardiologists to possess a comprehensive understanding of the underlying mechanisms governing these agents and to discern optimal strategies for their application across diverse clinical contexts. Thus, we briefly review these agents' pharmacological and hemodynamic properties and their reasonable clinical applications in cardiovascular settings. Critical interpretation of available data and the opportunities for future investigations are also highlighted.

Reinforcement of pimobendan with guideline-directed medical therapy may reduce the rehospitalization rates in patients with heart failure: retrospective cohort study

BACKGROUND

Pimobendan reportedly improves the subjective symptoms of heart failure. However, evidence of improved prognosis is lacking. This study aimed to determine whether reinforcing guideline-directed medical therapy (GDMT) improved rehospitalization rates for worsening heart failure in patients administered pimobendan.

METHODS

A total of 175 patients with heart failure who were urgently admitted to our hospital for worsening heart failure and who received pimobendan between January 2015 and February 2022 were included. Of the 175 patients, 44 were excluded because of in-hospital death at the time of pimobendan induction. The remaining 131 patients were divided into two groups, the reduced ejection fraction (rEF) (n = 93) and non-rEF (n = 38) groups, and further divided into the GDMT-reinforced and non-reinforced groups.

RESULTS

In patients with rEF, the rate of rehospitalization for heart failure was significantly lower in the GDMT-reinforced group than in the non-reinforced group (log-rank test, P = .04). However, the same trend was not observed in the non-rEF group.

CONCLUSIONS

Reinforcing GDMT may reduce the heart failure rehospitalization rate in patients with pimobendan administration and rEF. However, multicenter collaborative research is needed.

TRIAL REGISTRATION

IRB Approval by the Nippon Medical School Hospital Ethics Committee B-2021-433 (April 10, 2023).

Regional Variation in the Clinical Practice and Prognosis in Patients With Heart Failure With Reduced Ejection Fraction in Japan - A Report From the Japanese Registry of Acute Decompensated Heart Failure (JROADHF)

BACKGROUND

The present study aimed to clarify the regional variations in clinical practice and the prognosis of patients with heart failure with reduced ejection fraction (HFrEF) in Japan using the Japanese Registry of Acute Decompensated Heart Failure (JROADHF).

METHODS AND RESULTS

We recruited data of hospitalized patients with HFrEF (n=4,329) from the JROADHF. The patients were divided into 6 groups based on the region of Japan where they were hospitalized: Hokkaido-Tohoku (n=504), Kanto (n=958), Chubu (n=779), Kinki (n=902), Chugoku-Shikoku (n=446), and Kyushu (n=740). We compared the patients' characteristics, including etiology of HF and prognosis after discharge. The age of the patients was lowest in the Kanto and Kinki regions. In contrast, there were no differences in the prevalence of comorbidities, levels of B-type natriuretic peptide, or left ventricular EF among the 6 groups. Post-discharge cardiospecific prognosis, specifically, the composite of cardiac death or HF hospitalization, cardiac death, and HF hospitalization, was comparable among the 6 regions.

CONCLUSIONS

There were no differences in cardiospecific prognosis in patients with HFrEF among the 6 regions in Japan.

Novel Treatments of Hypertrophic Cardiomyopathy in GDMT for Heart Failure: A State-of-art Review

This state-of-the-art review discuss the available evidence on the use of novel treatments of hypertrophic cardiomyopathy such as omecamtiv mecarbil, EMD-57033, levosimendan, pimobendan, and mavacamten for the treatment of heart failure (HF) in the context of guideline-directed medical therapy (GDMT). The paper provides a detailed overview of these agents' mechanisms of action, potential benefits and limitations, and their effects on clinical outcomes. The review also evaluates the efficacy of the novel treatments in comparison to traditional medications such as digoxin. Finally, we seek to provide insight and guidance to clinicians and researchers in the management of HF patients.

Developments in Exercise Capacity Assessment in Heart Failure Clinical Trials and the Rationale for the Design of METEORIC-HF

Heart failure with reduced ejection fraction (HFrEF) is a highly morbid condition for which exercise intolerance is a major manifestation. However, methods to assess exercise capacity in HFrEF vary widely in clinical practice and in trials. We describe advances in exercise capacity assessment in HFrEF and a comparative analysis of how various therapies available for HFrEF impact exercise capacity. Current guideline-directed medical therapy has indirect effects on cardiac performance with minimal impact on measured functional capacity. Omecamtiv mecarbil is a novel selective cardiac myosin activator that directly increases cardiac contractility and in a phase 3 cardiovascular outcomes study significantly reduced the primary composite end point of time to first heart failure event or cardiovascular death in patients with HFrEF. The objective of the METEORIC-HF trial (Multicenter Exercise Tolerance Evaluation of Omecamtiv Mecarbil Related to Increased Contractility in Heart Failure) is to assess the effect of omecamtiv mecarbil versus placebo on multiple components of functional capacity in HFrEF. The primary end point is to test the effect of omecamtiv mecarbil compared with placebo on peak oxygen uptake as measured by cardiopulmonary exercise testing after 20 weeks of treatment. METEORIC-HF will provide state-of-the-art assessment of functional capacity by measuring ventilatory efficiency, circulatory power, ventilatory anaerobic threshold, oxygen uptake recovery kinetics, daily activity, and quality-of-life assessment. Thus, the METEORIC-HF trial will evaluate the potential impact of increased myocardial contractility with omecamtiv mecarbil on multiple important measures of functional capacity in ambulatory patients with symptomatic HFrEF. Registration: URL: https://clinicaltrials.gov; Unique identifier: NCT03759392.

Inotropic therapies in heart failure and cardiogenic shock: an educational review

Reduced systolic function is central to the pathophysiology and clinical sequelae of acute decompensated heart failure (ADHF) with reduced ejection fraction and cardiogenic shock. These clinical entities are the final common pathway for marked deterioration of right or left ventricular function and can occur in multiple clinical presentations including severe ADHF, myocardial infarction, post-cardiac surgery, severe pulmonary hypertension, and advanced or end-stage chronic heart failure. Inotropic therapies improve ventricular systolic function and may be divided into three classes on the basis of their mechanism of action (calcitropes, mitotropes, and myotropes). Most currently available therapies for cardiogenic shock are calcitropes which can provide critical haemodynamic support, but also may increase myocardial oxygen demand, ischaemia, arrhythmia, and mortality. Emerging therapies to improve cardiac function such as mitotropes (e.g. perhexiline, SGLT2i) or myotropes (e.g. omecamtiv mecarbil) may provide useful alternatives in the future.

From Genetic Mutations to Molecular Basis of Heart Failure Treatment: An Overview of the Mechanism and Implication of the Novel Modulators for Cardiac Myosin

Heart failure (HF) is a syndrome encompassing several important etiologies that lead to the imbalance between oxygen demand and supply. Despite the usage of guideline-directed medical therapy for HF has shown better outcomes, novel therapeutic strategies are desirable, especially for patients with preserved or mildly reduced left ventricular ejection fraction. In this regard, understanding the molecular basis for cardiomyopathies is expected to fill in the knowledge gap and generate new therapies to improve prognosis for HF. This review discusses an evolutionary mechanism designed to regulate cardiac contraction and relaxation through the most often genetically determined cardiomyopathies associated with HF. In addition, both the myosin inhibitor and myosin activator are promising new treatments for cardiomyopathies. A comprehensive review from genetic mutations to the molecular basis of direct sarcomere modulators will help shed light on future studies for a better characterization of HF etiologies and potential therapeutic targets.

Long-term management of congestive heart failure secondary to mitral stenosis in a ring-tailed lemur (Lemur catta)

CASE DESCRIPTION

A 15-year-old sexually intact female ring-tailed lemur (Lemur catta) was evaluated for a heart murmur and progressive radiographic cardiomegaly.

CLINICAL FINDINGS

The lemur was clinically normal at the time of initial evaluation. Results of transthoracic echocardiography performed when the animal was anesthetized indicated mitral valve stenosis and severe left atrial dilation. Three months later, signs of left-sided congestive heart failure (CHF; coughing, exercise intolerance, and tachypnea) were observed and confirmed by the presence of radiographic pulmonary edema.

TREATMENT AND OUTCOME

Medical treatment that consisted of aspirin, benazepril, furosemide, pimobendan, spironolactone, and ultimately torsemide in lieu of furosemide successfully controlled the lemur's clinical signs for 33 months after the development of CHF. Euthanasia was then elected on the basis of perceived poor quality of life because tachypnea became refractory to progressively higher dosages of diuretic. Necropsy confirmed mitral stenosis with severe left atrial dilation and chronic pulmonary congestion.

CLINICAL RELEVANCE

The present report described the long-term medical management of CHF secondary to mitral stenosis in a lemur. Mitral stenosis was suspected to be a congenital defect, similar to the cause of mitral stenosis reported for dogs and cats, rather than to be an acquired change in association with rheumatic heart disease as commonly occurs for people. The lemur's CHF was well managed for 33 months with treatment, including pimobendan, which was well tolerated.

A pilot study investigating the effect of pimobendan on the cardiac rhythm and selected echocardiographic parameters of healthy cats

INTRODUCTION

The effects of pimobendan on the heart rhythm in cats are unknown. The purpose of this pilot study was to evaluate the effect of pimobendan on the cardiac rhythm and selected echocardiographic parameters of cats.

ANIMALS, MATERIALS, AND METHODS

Six clinically healthy cats received each of four medication protocols for 15 days, with a washout period of at least one month between each protocol. The protocols were, pimobendan 0.5 mg/kg twice daily (high dosage group), pimobendan 0.25 mg/kg twice daily (standard dosage group), pimobendan 0.125 mg/kg twice daily (low dosage group), and Biofermin R, one tablet twice daily (placebo group). Twenty-four-hour ambulatory electrocardiogram recordings, blood pressure measurements, and echocardiographic examinations were performed after two weeks of each medication protocol. Electrocardiographic, echocardiographic, and blood pressure parameters were compared between the four groups.

RESULTS

The total number of escape/idioventricular/idiojunctional complexes in the high dosage group was significantly higher compared with the placebo, low dosage, and standard dosage groups (p < 0.001). The blood pressure; total number of heart beats per day; and mean, minimum, and maximum heart rates were not significantly different between the groups. The longitudinal strain rate and calculated cardiac output were significantly increased in the high and standard dosage groups.

CONCLUSIONS

The administration of pimobendan, especially at high doses, was associated with increased numbers of escape/idioventricular/idiojunctional complexes in some cats and echocardiographic parameters. Further studies are warranted to investigate both the mechanism underlying the observed changes and what, if any, clinical implications these changes might have in cats with heart disease.

Small Molecules acting on Myofilaments as Treatments for Heart and Skeletal Muscle Diseases

Hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM) are the most prevalent forms of the chronic and progressive pathological condition known as cardiomyopathy. These diseases have different aetiologies; however, they share the feature of haemodynamic abnormalities, which is mainly due to dysfunction in the contractile proteins that make up the contractile unit known as the sarcomere. To date, pharmacological treatment options are not disease-specific and rather focus on managing the symptoms, without addressing the disease mechanism. Earliest attempts at improving cardiac contractility by modulating the sarcomere indirectly (inotropes) resulted in unwanted effects. In contrast, targeting the sarcomere directly, aided by high-throughput screening systems, could identify small molecules with a superior therapeutic value in cardiac muscle disorders. Herein, an extensive literature review of 21 small molecules directed to five different targets was conducted. A simple scoring system was created to assess the suitability of small molecules for therapy by evaluating them in eight different criteria. Most of the compounds failed due to lack of target specificity or poor physicochemical properties. Six compounds stood out, showing a potential therapeutic value in HCM, DCM or heart failure (HF). Omecamtiv Mecarbil and Danicamtiv (myosin activators), Mavacamten, CK-274 and MYK-581 (myosin inhibitors) and AMG 594 (Ca2+-sensitiser) are all small molecules that allosterically modulate troponin or myosin. Omecamtiv Mecarbil showed limited efficacy in phase III GALACTIC-HF trial, while, results from phase III EXPLORER-HCM trial were recently published, indicating that Mavacamten reduced left ventricular outflow tract (LVOT) obstruction and diastolic dysfunction and improved the health status of patients with HCM. A novel category of small molecules known as "recouplers" was reported to target a phenomenon termed uncoupling commonly found in familial cardiomyopathies but has not progressed beyond preclinical work. In conclusion, the contractile apparatus is a promising target for new drug development.

Retrospective evaluation of the safety and tolerability of pimobendan in cats with obstructive vs nonobstructive cardiomyopathy

BACKGROUND

Pimobendan is frequently used off-label for treatments of cats with congestive heart failure (CHF). Concern exists regarding the safety of pimobendan in cats with outflow tract obstruction (OTO).

OBJECTIVES

In cats treated with pimobendan, incidence of adverse effects will not differ between cats with OTO vs cats with nonobstructive cardiomyopathy.

ANIMALS

Two-hundred sixty cats with CHF (57 with OTO, 203 with nonobstructive disease).

METHODS

Retrospective medical record review. Groups were compared using 2-sample t-tests, Wilcoxon rank-sum tests, and Fisher exact tests.

RESULTS

Compared to cats with nonobstructive cardiomyopathy, cats with OTO were younger (8.9 [interquartile range (IQR) 6.6] vs 10.8 [6.3] years, P = .0036), more likely to have a heart murmur (51/57 [90%] vs 76/203 [37.8%] cats, P < .0001), more likely to manifest CHF as pulmonary edema (53/57 [83%] vs 144/203 [70.9%] cats, P = .0004), and less likely to have pleural effusion (19/57 [33%] vs 122/203 [60.1%] cats, P = .0005). Adverse effects suspected to be related to pimobendan administration occurred in 12/260 cats (4.6%), including 11/203 cats (5.4%) with nonobstructive cardiomyopathy and 1/57 cat (2%) with OTO (P = .7). Pimobendan was discontinued due to adverse effects in 4/260 cats (1.5%), 3 with nonobstructive disease and 1 with OTO (P = 1.0). Acute adverse hemodynamic effects after pimobendan administration were not detected in any cats.

CONCLUSIONS AND CLINICAL IMPORTANCE

Pimobendan is well tolerated in cats with cardiomyopathy and CHF, regardless of the presence of OTO.

Effects of Pimobendan on Prolonging Time to Rehospitalization or Frequency of Rehospitalization in Patients with Heart Failure: A Retrospective Cohort Study Using a Medical Administrative Database (PREFER Study)

BACKGROUND

As approximately 24% of patients with chronic heart failure are rehospitalized within 1 year and heart failure is aggravated by repeated hospitalizations, greater importance was attached to the prevention of hospitalization.

OBJECTIVE

The objective of this study was to investigate the influence of pimobendan on rehospitalization of patients with advanced heart failure using a Japanese medical administrative database.

METHODS

From January 2010 to February 2018, patients hospitalized two or more times for heart failure were selected for analysis. The primary endpoint was the incidence of hospitalizations for heart failure during the follow-up period, which was compared between pimobendan prescription and non-prescription groups after propensity score matching.

RESULTS

The total number of patients with heart failure included during the study period was 1 421 110 and we matched 276 patients in both groups. The incidence of rehospitalization throughout the period to completion of follow-up was 365.23/1000 people/yr (95% confidence interval [CI]: 327.78-402.69) in the pimobendan prescription group and 537.81/1000 people/yr (95% CI: 492.36-583.27) in the non-prescription group. The cumulative incidence at 365 days was significantly lower in the pimobendan prescription group (pimobendan prescription group: 35.4% (95% CI: 29.8-41.8), non-prescription group: 51.2% (95% CI: 45.1-57.7), (P < 0.001). The adjusted hazard ratio in the pimobendan prescription group was 0.556 (95% CI: 0.426-0.725, P < 0.001).

CONCLUSION

Pimobendan was suggested to extend the time to rehospitalization for patients with advanced heart failure. It is necessary to verify the results of this study by performing a prospective study. In addition, the influence of pimobendan on general heart failure patients must be examined.

Pathogenesis and pathophysiology of heart failure with reduced ejection fraction: translation to human studies

Heart failure represents the end result of different pathophysiologic processes, which culminate in functional impairment. Regardless of its aetiology, the presentation of heart failure usually involves symptoms of pump failure and congestion, which forms the basis for clinical diagnosis. Pathophysiologic descriptions of heart failure with reduced ejection fraction (HFrEF) are being established. Most commonly, HFrEF is centred on a reactive model where a significant initial insult leads to reduced cardiac output, further triggering a cascade of maladaptive processes. Predisposing factors include myocardial injury of any cause, chronically abnormal loading due to hypertension, valvular disease, or tachyarrhythmias. The pathophysiologic processes behind remodelling in heart failure are complex and reflect systemic neurohormonal activation, peripheral vascular effects and localised changes affecting the cardiac substrate. These abnormalities have been the subject of intense research. Much of the translational successes in HFrEF have come from targeting neurohormonal responses to reduced cardiac output, with blockade of the renin-angiotensin-aldosterone system (RAAS) and beta-adrenergic blockade being particularly fruitful. However, mortality and morbidity associated with heart failure remains high. Although systemic neurohormonal blockade slows disease progression, localised ventricular remodelling still adversely affects contractile function. Novel therapy targeted at improving cardiac contractile mechanics in HFrEF hold the promise of alleviating heart failure at its source, yet so far none has found success. Nevertheless, there are increasing calls for a proximal, 'cardiocentric' approach to therapy. In this review, we examine HFrEF therapy aimed at improving cardiac function with a focus on recent trials and emerging targets.

Effect of pimobendan on physical fitness, lactate and echocardiographic parameters in dogs with preclinical mitral valve disease without cardiomegaly

Pimobendan has gained enormous importance in the treatment of mitral valve disease in dogs. The current consensus statement of the American College of Veterinary Internal Medicine (ACVIM) recommends a treatment for dogs with symptomatic disease and dogs with asymptomatic disease with radiographic and echocardiographic signs of cardiomegaly. To investigate whether these dogs also benefit from a therapy with pimobendan, 21 dogs with mitral valve disease ACVIM B1 underwent a standardized submaximal exercise test on a treadmill. In this double-blinded and randomized study, the animals were divided into two groups, one receiving pimobendan and the other a placebo. At the first visit and at every follow-up appointment (at days 90 and 180), heart rate during the complete exercise test and lactate before and after running were measured. In addition to this, a questionnaire was completed by the dogs’ owners and all dogs were given an echocardiographic examination to detect any changes and to observe if the disease had progressed. Due to the diagnosis of leishmaniosis, one dog in the pimobendan group was retrospectively removed from the study so that 20 dogs were included for statistical analysis. No differences were observed at any time between the pimobendan-group and the placebo-group regarding heart rate. At day 180, the increase in lactate after exercise was significantly lower than in the placebo-group. The increase in the pimobendan-group at day 180 was lower than at day 90. Most of the dog owners from the pimobendan-group declared that their dogs were more active at day 90 (6/10) and at day 180 (8/10), while most dog owners from the placebo-group observed no changes regarding activity at day 90 (8/10) and day 180 (6/10). It can be concluded that the results of this study indicate that some dogs with mitral valve disease ACVIM B1 might benefit from a therapy with pimobendan.

Why has positive inotropy failed in chronic heart failure? Lessons from prior inotrope trials

Current pharmacological therapies for heart failure with reduced ejection fraction are largely either repurposed anti‐hypertensives that blunt overactivation of the neurohormonal system or diuretics that decrease congestion. However, they do not address the symptoms of heart failure that result from reductions in cardiac output and reserve. Over the last few decades, numerous attempts have been made to develop and test positive cardiac inotropes that improve cardiac haemodynamics. However, definitive clinical trials have failed to show a survival benefit. As a result, no positive inotrope is currently approved for long‐term use in heart failure. The focus of this state‐of‐the‐art review is to revisit prior clinical trials and to understand the causes for their findings. Using the learnings from those experiences, we propose a framework for future trials of such agents that maximizes their potential for success. This includes enriching the trials with patients who are most likely to derive benefit, using biomarkers and imaging in trial design and execution, evaluating efficacy based on a wider range of intermediate phenotypes, and collecting detailed data on functional status and quality of life. With a rapidly growing population of patients with advanced heart failure, the epidemiologic insignificance of heart transplantation as a therapeutic intervention, and both the cost and morbidity associated with ventricular assist devices, there is an enormous potential for positive inotropic therapies to impact the outcomes that matter most to patients.

Rosmarinus officinalis L. (rosemary) as therapeutic and prophylactic agent

Rosmarinus officinalis L. (rosemary) is a medicinal plant native to the Mediterranean region and cultivated around the world. Besides the therapeutic purpose, it is commonly used as a condiment and food preservative. R. officinalis L. is constituted by bioactive molecules, the phytocompounds, responsible for implement several pharmacological activities, such as anti-inflammatory, antioxidant, antimicrobial, antiproliferative, antitumor and protective, inhibitory and attenuating activities. Thus, in vivo and in vitro studies were presented in this Review, approaching the therapeutic and prophylactic effects of R. officinalis L. on some physiological disorders caused by biochemical, chemical or biological agents. In this way, methodology, mechanisms, results, and conclusions were described. The main objective of this study was showing that plant products could be equivalent to the available medicines.

Elucidation of the Strongest Predictors of Cardiovascular Events in Patients with Heart Failure

BACKGROUND

In previous retrospective studies, we identified the 50 most influential clinical predictors of cardiovascular outcomes in patients with heart failure (HF). The present study aimed to use the novel limitless-arity multiple-testing procedure to filter these 50 clinical factors and thus yield combinations of no more than four factors that could potentially predict the onset of cardiovascular events. A Kaplan-Meier analysis was used to investigate the importance of the combinations.

METHODS

In a multi-centre observational trial, we prospectively enrolled 213 patients with HF who were hospitalized because of exacerbation, discharged according to HF treatment guidelines and observed to monitor cardiovascular events. After the observation period, we stratified patients according to whether they experienced cardiovascular events (rehospitalisation or cardiovascular death).

FINDINGS

Among 77,562 combinations of fewer than five clinical parameters, we identified 151 combinations that could potentially explain the occurrence of cardiovascular events. Of these, 145 combinations included the use of inotropic agents, whereas the remaining 6 included the use of diuretics without bradycardia or tachycardia, suggesting that the high probability of cardiovascular events is exclusively determined by these two clinical factors. Importantly, Kaplan-Meier curves demonstrated that the use of inotropes or of diuretics without bradycardia or tachycardia were independent predictors of a markedly worse cardiovascular prognosis.

INTERPRETATION

Patients treated with either inotropic agents or diuretics without bradycardia or tachycardia were at a higher risk of cardiovascular events. The uses of these drugs, regardless of heart rate, are the strongest clinical predictors of cardiovascular events in patients with HF.

Early sensitization of myofilaments to Ca2+ prevents genetically linked dilated cardiomyopathy in mice

Background

Dilated cardiomoypathies (DCM) are a heterogeneous group of inherited and acquired diseases characterized by decreased contractility and enlargement of cardiac chambers and a major cause of morbidity and mortality. Mice with Glu54Lys mutation in α-tropomyosin (Tm54) demonstrate typical DCM phenotype with reduced myofilament Ca2+ sensitivity. We tested the hypothesis that early sensitization of the myofilaments to Ca2+ in DCM can prevent the DCM phenotype.

Methods and results

To sensitize Tm54 myofilaments, we used a genetic approach and crossbred Tm54 mice with mice expressing slow skeletal troponin I (ssTnI) that sensitizes myofilaments to Ca2+. Four groups of mice were used: non-transgenic (NTG), Tm54, ssTnI and Tm54/ssTnI (DTG). Systolic function was significantly reduced in the Tm54 mice compared to NTG, but restored in DTG mice. Tm54 mice also showed increased diastolic LV dimensions and HW/BW ratios, when compared to NTG, which were improved in the DTG group. β-myosin heavy chain expression was increased in the Tm54 animals compared to NTG and was partially restored in DTG group. Analysis by 2D-DIGE indicated a significant decrease in two phosphorylated spots of cardiac troponin I (cTnI) in the DTG animals compared to NTG and Tm54. Analysis by 2D-DIGE also indicated no significant changes in troponin T, regulatory light chain, myosin binding protein C and tropomyosin phosphorylation.

Conclusion

Our data indicate that decreased myofilament Ca2+ sensitivity is an essential element in the pathophysiology of thin filament linked DCM. Sensitization of myofilaments to Ca2+ in the early stage of DCM may be a useful therapeutic strategy in thin filament linked DCM.

Developing Drugs for Heart Failure With Reduced Ejection Fraction: What Have We Learned From Clinical Trials?

There remains a large unmet need for new therapies in the treatment of heart failure with reduced ejection fraction (HFrEF). In the early drug development phase, the therapeutic potential of a drug is not yet fully understood and trial endpoints other than mortality are needed to guide drug development decisions. While a true surrogate marker for mortality in heart failure (HF) remains elusive, the successes and failures of previous trials can reveal markers that support clinical Go/NoGo decisions.

Korean Guidelines for Diagnosis and Management of Chronic Heart Failure

The prevalence of heart failure (HF) is skyrocketing worldwide, and is closely associated with serious morbidity and mortality. In particular, HF is one of the main causes for the hospitalization and mortality in elderly individuals. Korea also has these epidemiological problems, and HF is responsible for huge socioeconomic burden. However, there has been no clinical guideline for HF management in Korea. 
The present guideline provides the first set of practical guidelines for the management of HF in Korea and was developed using the guideline adaptation process while including as many data from Korean studies as possible. The scope of the present guideline includes the definition, diagnosis, and treatment of chronic HF with reduced/preserved ejection fraction of various etiologies.

Treatment of Heart Failure with Abnormal Left Ventricular Systolic Function in Older Adults

Heart failure (HF) with abnormal left ventricular (LV) ejection fraction should be identified and treated. Treat hypertension with diuretics, angiotensin-converting enzyme (ACE) inhibitors, and β-blockers. Treat myocardial ischemia with nitrates and β-blockers. Treat volume overload and HF with diuretics. Treat HF with ACE inhibitors and β-blockers. Sacubitril/valsartan may be used instead of an ACE inhibitor or ARB in chronic symptomatic HF and abnormal LV ejection fraction. Add isosorbide dinitrate/hydralazine in African Americans with class II to IV HF treated with diuretics, ACE inhibitors, and β-blockers. Exercise training is recommended. Indications for implantable cardioverter-defibrillator and cardiac resynchronization therapy are discussed.

The Role of Positive Inotropic Drugs in the Treatment of Older Adults with Heart Failure and Reduced Ejection Fraction

Positive inotropic drugs have long been studied for their potential benefits in patients with heart failure and reduced ejection fraction (HFrEF). Although there has been an extensive amount of research about the clinical effects of these drugs in general, few studies examined their effect in older patients. Therefore, there is little or no evidence to guide the use of positive inotropes in older patients with HFrEF. However, recommendations from national heart failure guidelines may be generalized to older HFrEF patients on an individual basis, taking into consideration the basic geriatric principles of pharmacotherapy: start low and go slow.

Development and Evolution of a Hierarchical Clinical Composite End Point for the Evaluation of Drugs and Devices for Acute and Chronic Heart Failure: A 20-Year Perspective

Traditional approaches to the assessment of new treatments for heart failure have generally evaluated individual components of the syndrome at fixed points in time or have relied on surrogate physiological measures that are poorly correlated with the clinical status of patients. Conventional time-to-event trials that focus on morbidity and mortality represent an important methodological advance, but they generally assign undue weight to clinical events of less importance and are insensitive to difference in functional capacity among individuals who do not experience a clinical event during follow-up. Twenty years ago, a hierarchical clinical composite was developed to address these limitations; it aims to assess the clinical course of patients as a physician would in practice by combining a symptomatic assessment of the patient at each visit with an evaluation of the clinical stability of the patient between visits. The composite does not generate a numeric score by summing arbitrarily assigned weights to certain symptoms or events; instead, the composite ranks relevant measures and outcomes according to clinical priority. In doing so, the clinical composite minimizes the biases created by noncompleting patients in the assessment of symptoms or exercise tolerance while expanding the range of patients who contribute to the treatment difference in a typical morbidity and mortality trial. When applied appropriately, the hierarchical clinical composite end point has reliably distinguished effective from ineffective treatments. The composite may have particular advantages in the evaluation of new devices and transcatheter interventions in chronic heart failure and of new drugs for acute heart failure. Recent modifications enhance its discriminant characteristics and its ability to accurately assess the efficacy of novel interventions for heart failure.

An optimal Wilcoxon-Mann-Whitney test of mortality and a continuous outcome

We consider a two-group randomized clinical trial, where mortality affects the assessment of a follow-up continuous outcome. Using the worst-rank composite endpoint, we develop a weighted Wilcoxon-Mann-Whitney test statistic to analyze the data. We determine the optimal weights for the Wilcoxon-Mann-Whitney test statistic that maximize its power. We derive a formula for its power and demonstrate its accuracy in simulations. Finally, we apply the method to data from an acute ischemic stroke clinical trial of normobaric oxygen therapy.

Current treatment of heart failure with reduction of left ventricular ejection fraction

Heart failure is the commonest cause of hospitalization and of rehospitalization This review paper is a comprehensive review of current treatment of heart failure in 2016. The target of this review is all health care professionals who treat patients with heart failure. Areas covered: This article discusses stages of heart failure, treatment of heart failure with general measures, and drug therapy with diuretics, angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, beta blockers, aldosterone antagonists, isosorbide dinitrate plus hydralazine, digoxin, other neurohormonal antagonists, sacubitril/valsartan, calcium channel blockers, and ivabradine. This article also discusses treatment of heart failure with use of cardiac resynchronization therapy, implantable cardioverter-defibrillators, and surgical therapy, and management of end-stage heart failure. This paper was written after an extensive Medline search reviewing articles written from 1970 through May, 2016. Expert commentary: Our approach as physicians must emphasize prevention of heart failure as well as treating it. Risk factors for developing heart failure, especially hypertension, must be better controlled starting in childhood. I concur with the current heart failure treatment guidelines (Tables 1 and 2 in this paper).

Update of treatment of heart failure with reduction of left ventricular ejection fraction

Underlying and precipitating causes of heart failure (HF) with reduced left ventricular ejection fraction (HFrEF) should be identified and treated when possible. Hypertension should be treated with diuretics, angiotensin-converting enzyme (ACE) inhibitors, and β-blockers. Diuretics are the first-line drugs in the treatment of patients with HFrEF and volume overload. Angiotensin-converting enzyme inhibitors and β-blockers (carvedilol, sustained-release metoprolol succinate, or bisoprolol) should be used in treatment of HFrEF. Use an angiotensin II receptor blocker (ARB) (candesartan or valsartan) if intolerant to ACE inhibitors because of cough or angioneurotic edema. Sacubitril/valsartan may be used instead of an ACE inhibitor or ARB in patients with chronic symptomatic HFrEF class II or III to further reduce morbidity and mortality. Add an aldosterone antagonist (spironolactone or eplerenone) in selected patients with class II-IV HF who can be carefully monitored for renal function and potassium concentration. (Serum creatinine should be ≤ 2.5 mg/dl in men and ≤ 2.0 mg/dl in women. Serum potassium should be < 5.0 mEq/l). Add isosorbide dinitrate plus hydralazine in patients self-described as African Americans with class II-IV HF being treated with diuretics, ACE inhibitors, and β-blockers. Ivabradine can be used in selected patients with HFrEF.

Quality of life and long-term mortality in patients with advanced chronic heart failure treated with intermittent low-dose intravenous inotropes in an outpatient setting

AIMS

There are limited data on the effect of low-dose, intermittent inotropic therapy in an outpatient setting on the quality of life (QOL) in patients with advanced refractory heart failure (HF) symptoms. We aimed to analyse the effect of this treatment modality on QOL and subsequent survival.

METHODS AND RESULTS

The study population comprised 287 consecutive patients with advanced refractory HF symptoms who were treated with low-dose, intravenous intermittent inotropic therapy in the HF Day Care Service at Sheba Medical Centre between September 2000 and September 2012. All patients completed a baseline Minnesota Living with Heart Failure Questionnaire (MLWHFQ), and 137 (48%) completed a 1 year follow-up questionnaire. MLWHFQ scores' means ranged from 0 (better QOL) to 5 (worse QOL). Mean age was 68 ± 12, 86% were men, 77% had ischaemic cardiomyopathy, and the mean left ventricle ejection fraction (LVEF) was 26% ± 13. The mean baseline MLWHFQ score was 3.1 (±1), while the mean at 1 year of treatment was of 2.7 (±1.1), indicating an overall improvement in QOL associated with intermittent low-dose inotrope therapy (p < 0.01). Multivariate analysis showed that younger age, non-ischaemic cardiomyopathy, and worse renal function were independently associated with improvement in QOL at 1 year. Improvement in QOL was not associated with a significant survival benefit during subsequent follow-up.

CONCLUSIONS

In patients with advanced refractory HF symptoms, treatment with low-dose, intermittent intravenous inotropes in an outpatient setting is associated with significant improvement in QOL. However, improvement in QOL in this population does not appear to affect subsequent long-term survival.

Quality of life assessment in heart failure interventions: a 10-year (1996–2005) review

The increasing prevalence and poor prognosis associated with heart failure have prompted research to focus on improving quality of life (QoL) for heart failure patients. Research from 1996–2005 was systematically reviewed to identify randomized controlled trials that assessed QoL in heart failure. In 120 studies, 44 were medication trials; 19 surgical/procedural interventions; and 57 patient care/service delivery interventions. Studies were summarized in terms of aim, population, QoL measures used and QoL findings. Studies used 47 different measures of QoL-generic, health-related, condition-specific, domain-specific and utility measures. Most used a single QoL measure. In 87%, a condition specific QoL measure was used, with the Minnesota Living with Heart Failure Questionnaire being the favoured assessment tool. The range of QoL measures in use poses challenges for development of cumulative knowledge. Although comparability across studies is important, this must be informed by the responsiveness of the instrument selected. As carried out in other cardiac groups, comparative evaluations of instrument responsiveness are needed in heart failure. Eur J Cardiovasc Prev Rehabil 14:589-607 © 2007 The European Society of Cardiology

Heart failure epidemiology and novel treatments in Japan: facts and numbers

Japan has the highest proportion of older people in the world, 25.9% of the population were aged 65 or above in 2014. Although there have been no population‐based studies that precisely examined the prevalence of heart failure in Japan, one report estimated the number of Japanese outpatients with left ventricular dysfunction was 979, 000 (0.8% of total population), which was projected to increase gradually as the population ages, reaching 1.3 million by 2030. Ischemic etiology was less frequently observed in Japan (31–47%) than in western population (54–57%). The prevalence of HF with preserved ejection fraction was similar between Japan (34–68%) and western countries (34–51%). Non‐cardiac co‐morbidities such as chronic obstructive pulmonary diseases and anemia were observed in 6–9% in Japan and 19–31% in western countries, and 35–58% in Japan and 37–56% in western countries, respectively. The definition of chronic kidney disease widely differed among studies. A relatively good survival prognosis in Japanese patients has been discussed. One‐year mortality after discharge from initial hospitalization was 9–12%, which seems to be better than the western cohort. Although length of stay was remarkably longer in Japan (15–21 days) than western countries (4–9 days), it will have to be shortened, as Japan is now being faced with an upcoming HF pandemic. Some treatments in Japan are not approved outside Japan. Such treatments include carperitide infusion (used in 58% of hospitalized HF), nicorandil infusion (9.6%), and oral pimobendan (5%). More recently, landiolol and tolvaptan have been approved. Although these drugs might have a potential to be an effective therapeutic option, lack of corroborating evidence in many of such treatments would emphasize the need for larger clinical trials.

Inotropes and inodilators for acute heart failure: sarcomere active drugs in focus

Acute heart failure (AHF) emerges as a major and growing epidemiological concern with high morbidity and mortality rates. Current therapies in patients with acute heart failure rely on different strategies. Patients with hypotension, hypoperfusion, or shock require inotropic support, whereas diuretics and vasodilators are recommended in patients with systemic or pulmonary congestion. Traditionally inotropic agents, referred to as Ca²⁺ mobilizers load the cardiomyocyte with Ca²⁺ and thereby increase oxygen consumption and risk for arrhythmias. These limitations of traditional inotropes may be avoided by sarcomere targeted agents. Direct activation of the cardiac sarcomere may be achieved by either sensitizing the cardiac myofilaments to Ca²⁺ or activating directly the cardiac myosin. In this review, we focus on sarcomere targeted inotropic agents, emphasizing their mechanisms of action and overview the most relevant clinical considerations.

Effect of pimobendan on the incidence of arrhythmias in small breed dogs with myxomatous mitral valve degeneration

OBJECTIVE

To determine if pimobendan, a phosphodiesterase III inhibitor and calcium sensitizer with positive survival benefits, has an effect on incidence of arrhythmias compared to placebo in small breed dogs with congestive heart failure (CHF) due to myxomatous mitral valve degeneration (MMVD).

ANIMALS

Eight client-owned small breed dogs (<15 kg) with CHF due to MMVD.

METHODS

A prospective double-blind randomized placebo-controlled crossover study design was used. Data were recorded at baseline and 2 weeks post-administration of placebo or pimobendan. Average heart rate and incidence of arrhythmia were determined from 24 h Holter analysis. Owners completed a quality of life (QOL) questionnaire at each time point and recorded sleeping respiratory rates (SRR). Mixed effects analysis of variance, with dog as the random variable was used to compare values obtained between baseline, placebo, and pimobendan.

RESULTS

Compared to baseline, QOL scores were significantly improved following administration of either placebo or pimobendan (p = 0.021 and p < 0.001, respectively). No significant differences in type or incidence of supraventricular or ventricular arrhythmia were identified. Average heart rate with pimobendan was significantly lower than baseline (p < 0.001). Compared to baseline, SRR was significantly lower with pimobendan (p = 0.004), and significantly different from placebo (p = 0.045).

CONCLUSIONS

No significant difference between pimobendan and placebo was found on incidence of supraventricular or ventricular arrhythmia. The decrease in average heart rate and SRR may be reflective of superior heart failure control achieved with pimobendan therapy.

Stage-dependent benefits and risks of pimobendan in mice with genetic dilated cardiomyopathy and progressive heart failure

BACKGROUND AND PURPOSE

The Ca(2+) sensitizer pimobendan is a unique inotropic agent that improves cardiac contractility with less of an increase in oxygen consumption and potentially fewer adverse effects on myocardial remodelling and arrhythmia, compared with traditional inotropes. However, clinical trials report contradictory effects of pimobendan in patients with heart failure (HF). We provide mechanistic experimental evidence of the efficacy of pimobendan using a novel mouse model of progressive HF.

EXPERIMENTAL APPROACH

A knock-in mouse model of human genetic dilated cardiomyopathy, which shows a clear transition from compensatory to end-stage HF at a fixed time during growth, was used to evaluate the efficacy of pimobendan and explore the underlying molecular and cellular mechanisms.

KEY RESULTS

Pimobendan prevented myocardial remodelling in compensated HF and significantly extended life span in both compensated and end-stage HF, but dose-dependently increased sudden death in end-stage HF. In cardiomyocytes isolated from end-stage HF mice, pimobendan induced triggered activity probably because of early or delayed afterdepolarizations. The L-type Ca(2+) channel blocker verapamil decreased the incidence of triggered activity, suggesting that this was from over-elevated cytoplasmic Ca(2+) through increased Ca(2+) entry by PDE3 inhibition under diminished sarcoplasmic reticulum Ca(2+) reuptake and increased Ca(2+) leakage from sarcoplasmic reticulum in end-stage HF.

CONCLUSIONS AND IMPLICATIONS

Pimobendan was beneficial regardless of HF stage, but increased sudden cardiac death in end-stage HF with extensive remodelling of Ca(2+) handling. Reduction of cytoplasmic Ca(2+) elevated by PDE3 inhibition might decrease this risk of sudden cardiac death.

In vivo effects of propyl gallate, a novel Ca(2+) sensitizer, in a mouse model of dilated cardiomyopathy caused by cardiac troponin T mutation

AIMS

We have previously demonstrated that propyl gallate has a Ca(2+) sensitizing effect on the force generation in membrane-permeabilized (skinned) cardiac muscle fibers. However, in vivo beneficial effects of propyl gallate as a novel Ca(2+) sensitizer remain uncertain. In the present study, we aim to explore in vivo effects of propyl gallate.

MAIN METHODS

We compared effects of propyl gallate on ex vivo intact cardiac muscle fibers and in vivo hearts in healthy mice with those of pimobendan, a clinically used Ca(2+) sensitizer. The therapeutic effect of propyl gallate was investigated using a mouse model of dilated cardiomyopathy (DCM) with reduced myofilament Ca(2+) sensitivity due to a deletion mutation ΔK210 in cardiac troponin T.

KEY FINDINGS

Propyl gallate, as well as pimobendan, showed a positive inotropic effect. Propyl gallate slightly increased the blood pressure without changing the heart rate in healthy mice, whereas pimobendan decreased the blood pressure probably through vasodilation via inhibition of phosphodiesterase and increased the heart rate. Propyl gallate prevented cardiac remodeling and systolic dysfunction and significantly improved the life-expectancy of knock-in mouse model of DCM with reduced myofilament Ca(2+) sensitivity due to a mutation in cardiac troponin T. On the other hand, gallate, a similarly strong antioxidant polyphenol lacking Ca(2+) sensitizing action, had no beneficial effects on the DCM mice.

SIGNIFICANCE

These results suggest that propyl gallate might be useful for the treatment of inherited DCM caused by a reduction in the myofilament Ca(2+) sensitivity.