Overview of randomized clinical trials in acute heart failure syndromes

Pathophysiology and Therapeutic Approaches to Acute Decompensated Heart Failure

Acute decompensated heart failure (ADHF) is one of the leading admission diagnoses worldwide, yet it is an entity with incompletely understood pathophysiology and limited therapeutic options. Patients admitted for ADHF have high in-hospital morbidity and mortality, as well as frequent rehospitalizations and subsequent cardiovascular death. This devastating clinical course is partly due to suboptimal medical management of ADHF with persistent congestion upon hospital discharge and inadequate predischarge initiation of life-saving guideline-directed therapies. While new drugs for the treatment of chronic HF continue to be approved, there has been no new therapy approved for ADHF in decades. This review will focus on the current limited understanding of ADHF pathophysiology, possible therapeutic targets, and current limitations in expanding available therapies in light of the unmet need among these high-risk patients.

Heart failure: role and point of view of cardiac intensivist

Heart failure is an acute or chronic syndrome where the heart is unable to provide adequate amount of oxygen to body tissues. The treatment of heart failure aims to give an immediate answer in terms of regression of volume overload and restoration of hemodynamic stability and then to ensure management of clinical exacerbation, reduction in hospital stay, and increasing of survival. The pharmacological treatment of heart failure includes drugs with different strength of evidence. When the patient is no more responsive to medical therapy a non-pharmacological approach may be required. The first step is cardiac resynchronization therapy and implantable cardiac defibrillator. Then hospitalization and inotropic support may be needed. When cardiac disease reaches the end stage, the severe decrease in multi organ perfusion requires a quick therapeutic response. This is a time dependent scenario, when mechanical circulatory support (MCS) plays a crucial role. MCS may be used as temporary hemodynamic support on situations where myocardial recovery is likely, such as after revascularization and in cases of fulminant acute myocarditis. Conversion to ventricular assist devices or transplantation should be considered if longer duration of MCS is required. Advances in the treatment of cardiogenic shock patients in terms of pharmacological therapies, short term and long term MCS could provide opportunities to improve survival, but they also increase the complexity of clinical care. For this reason a multidisciplinary shock team approach is paramount for early symptom detection, to guide initial haemodynamic therapy and for the right choice of MCS device at the right time.

Kardiologie

In der internistischen Intensivmedizin stellen die kardiologischen Erkrankungen die häufigsten Akutfälle dar. Das Management des akuten Koronarsyndroms, der akuten Herzinsuffizienz bzw. des kardiogenen Schocks sowie der Umgang mit Herzrhythmusstörungen nehmen entsprechend der Häufigkeiten einen bedeutsamen Platz ein. Die orientierende Echokardiographie findet dabei nicht nur als Notfalldiagnostikum, sondern auch zur Beurteilung der Hämodynamik zunehmende intensivmedizinische Anwendung. Dieses Kapitel berücksichtigt daher sowohl die hämodynamische Überwachung als auch die Behandlung aller relevanten kardiologischen Krankheitsbilder in der internistischen Intensivmedizin.

A randomized controlled trial of levosimendan to reduce mortality in high-risk cardiac surgery patients (CHEETAH): Rationale and design

OBJECTIVE

Patients undergoing cardiac surgery are at risk of perioperative low cardiac output syndrome due to postoperative myocardial dysfunction. Myocardial dysfunction in patients undergoing cardiac surgery is a potential indication for the use of levosimendan, a calcium sensitizer with 3 beneficial cardiovascular effects (inotropic, vasodilatory, and anti-inflammatory), which appears effective in improving clinically relevant outcomes.

DESIGN

Double-blind, placebo-controlled, multicenter randomized trial.

SETTING

Tertiary care hospitals.

INTERVENTIONS

Cardiac surgery patients (n = 1,000) with postoperative myocardial dysfunction (defined as patients with intraaortic balloon pump and/or high-dose standard inotropic support) will be randomized to receive a continuous infusion of either levosimendan (0.05-0.2 μg/[kg min]) or placebo for 24-48 hours.

MEASUREMENTS AND MAIN RESULTS

The primary end point will be 30-day mortality. Secondary end points will be mortality at 1 year, time on mechanical ventilation, acute kidney injury, decision to stop the study drug due to adverse events or to start open-label levosimendan, and length of intensive care unit and hospital stay. We will test the hypothesis that levosimendan reduces 30-day mortality in cardiac surgery patients with postoperative myocardial dysfunction.

CONCLUSIONS

This trial is planned to determine whether levosimendan could improve survival in patients with postoperative low cardiac output syndrome. The results of this double-blind, placebo-controlled randomized trial may provide important insights into the management of low cardiac output in cardiac surgery.

Half-molar sodium lactate infusion improves cardiac performance in acute heart failure: a pilot randomised controlled clinical trial

Introduction

Acute heart failure (AHF) is characterized by inadequate cardiac output (CO), congestive symptoms, poor peripheral perfusion and end-organ dysfunction. Treatment often includes a combination of diuretics, oxygen, positive pressure ventilation, inotropes and vasodilators or vasopressors. Lactate is a marker of illness severity but is also an important metabolic substrate for the myocardium at rest and during stress. We tested the effects of half-molar sodium lactate infusion on cardiac performance in AHF.

Methods

We conducted a prospective, randomised, controlled, open-label, pilot clinical trial in 40 patients fulfilling two of the following three criteria for AHF: (1) left ventricular ejection fraction <40%, (2) acute pulmonary oedema or respiratory failure of predominantly cardiac origin requiring mechanical ventilation and (3) currently receiving vasopressor and/or inotropic support. Patients in the intervention group received a 3 ml/kg bolus of half-molar sodium lactate over the course of 15 minutes followed by 1 ml/kg/h continuous infusion for 24 hours. The control group received only a 3 ml/kg bolus of Hartmann’s solution without continuous infusion. The primary outcome was CO assessed by transthoracic echocardiography 24 hours after randomisation. Secondary outcomes included a measure of right ventricular systolic function (tricuspid annular plane systolic excursion (TAPSE)), acid-base balance, electrolyte and organ function parameters, along with length of stay and mortality.

Results

The infusion of half-molar sodium lactate increased (mean ± SD) CO from 4.05 ± 1.37 L/min to 5.49 ± 1.9 L/min (P < 0.01) and TAPSE from 14.7 ± 5.5 mm to 18.3 ± 7 mm (P = 0.02). Plasma sodium and pH increased (136 ± 4 to 146 ± 6 and 7.40 ± 0.06 to 7.53 ± 0.03, respectively; both P < 0.01), but potassium, chloride and phosphate levels decreased. There were no significant differences in the need for vasoactive therapy, respiratory support, renal or liver function tests, duration of ICU and hospital stay or 28- and 90-day mortality.

Conclusions

Infusion of half-molar sodium lactate improved cardiac performance and led to metabolic alkalosis in AHF patients without any detrimental effects on organ function.

Trial registration

Clinicaltrials.gov NCT01981655. Registered 13 August 2013.

Effect of levosimendan on the short-term clinical course of patients with acutely decompensated heart failure

BACKGROUND

This study evaluated the efficacy and safety of levosimendan, a positive inotropic drug with vasodilator effects, given intravenously to patients with acutely decompensated heart failure (ADHF).

METHODS

We performed 2 sequential trials, the first to develop a new measure of efficacy in 100 patients, and the second to use this measure to evaluate levosimendan in an additional 600 patients. Patients admitted with ADHF received placebo or intravenous levosimendan for 24 h in addition to standard treatment. The primary endpoint was a composite that evaluated changes in clinical status during the first 5 days after randomization.

RESULTS

In the 600-patient trial, more levosimendan than placebo patients (58 vs. 44) were improved at all 3 pre-specified time points (6 h, 24 h, and 5 days), whereas fewer levosimendan patients (58 vs. 82) experienced clinical worsening (p = 0.015 for the difference between the groups). These differences were apparent, despite more frequent intensification of adjunctive therapy in the placebo group (79 vs. 45 patients). Improvements in patient self-assessment and declines in B-type natriuretic peptide levels with levosimendan persisted for 5 days and were associated with reduced length of stay (p = 0.009). Similar findings were present in the 100-patient pilot trial. Levosimendan was associated with more frequent hypotension and cardiac arrhythmias during the infusion period and a numerically higher risk of death across the 2 trials (49 of 350 on a regimen of levosimendan vs. 40 of 350 on a regimen of placebo at 90 days, p = 0.29).

CONCLUSIONS

In patients with ADHF, intravenous levosimendan provided rapid and durable symptomatic relief. As dosed in this trial, levosimendan was associated with an increased risk of adverse cardiovascular events. (Evaluation of Intravenous Levosimendan Efficacy in the Short Term Treatment of Decompensated Chronic Heart Failure; NCT00048425).

End-point selection for acute heart failure trials

The appropriate selection of response variables for clinical trials of new therapies for acute heart failure (AHF) is a complex process with major trade-offs. For one therapeutic approach to be considered superior to another, it must produce clinically significant improvements in making patients live longer, making patients feel better, or saving resources without adversely affecting these two goals. This review outlines factors that complicate AHF end-point selection, discusses a variety of end points used in recently completed and ongoing AHF studies, and suggests directions for future design and standardization of end points across AHF trials.

Levosimendan neither improves nor worsens mortality in patients with cardiogenic shock due to ST-elevation myocardial infarction

Background:

The aim of this study was to evaluate the effect of levosimendan on mortality in cardiogenic shock (CS) after ST elevation myocardial infarction (STEMI).

Methods and results:

Data were obtained prospectively from the SCAAR (Swedish Coronary Angiography and Angioplasty Register) and the RIKS-HIA (Register of Information and Knowledge about Swedish Heart Intensive Care Admissions) about 94 consecutive patients with CS due to STEMI. Patients were classified into levosimendan-mandatory and levosimendan-contraindicated cohorts. Inotropic support with levosimendan was mandatory in all patients between January 2004 and December 2005 (n = 46). After the SURVIVE and REVIVE II studies were presented, levosimendan was considered contraindicated and was not used in consecutive patients between December 2005 and December 2006 (n = 48). The cohorts were similar with respect to pre-treatment characteristics and concomitant medications. There was no difference in the incidence of new-onset atrial fibrillation, in-hospital cardiac arrest and length of stay at the coronary care unit. There was no difference in adjusted mortality at 30 days and at one year.

Conclusion:

The use of levosimendan neither improves nor worsens mortality in patients with CS due to STEMI. Well-designed randomized clinical trials are needed to define the role of inotropic therapy in the treatment of CS.

Sepsis and septic shock: pathophysiological and cardiovascular background as basis for therapy

INTRODUCTION

Sepsis and septic shock are common causes for admission to intensive care units. The morbidity and mortality remain unacceptably high despite the advanced treatments.

OBJECTIVES

To review the most commonly reported underlying mechanisms of sepsis and septic shock, besides discussion of sepsis-induced cardiovascular dysfunction. Therapeutic strategies for sepsis-induced myocardial depression are briefly discussed.

DATA SYNTHESIS

The development of sepsis and septic shock is multifactorial. Two major mechanisms contribute to the haemodynamic collapse. The extrinsic and intrinsic mechanisms induce a complex cascade which results in the release of pro- and anti-inflammatory mediators. Sepsis develops when the initial, appropriate host response to an infection becomes amplified and then dysregulated leading to haemodynamic and circulatory changes. The pro-inflammatory mediators tumour necrosis factor alpha, interleukin-beta and nitric oxide play a significant role in sepsis-related hypotension, shock and depression of cardiomyocyte contractility. Septic cardiac dysfunction can be explained by various mechanisms: changes in circulating volume, down-regulation of beta-adrenergic receptors, depressed post-receptor signalling pathways, reduced calcium release from the sarcoplasmic reticulum and impaired electromechanical coupling and reduced calcium sensibility at the myofibrillar level. Mitochondrial derangement seems to be of great importance in tissue injury and sepsis-associated multi organ failure. There is no consistent protocol for treating sepsis and septic shock. Guidelines include early goal-directed therapy, source control and haemodynamic supportive measures.

CONCLUSION

Further studies are needed to distinguish the importance of these various mechanisms. We recommend that further investigational work should focus on the recovery of the mitochondria-related bio-energetic shut down as the mitochondria could play a key role in the understanding of apoptosis and protective measures. Understanding the pathophysiology of sepsis and septic shock will inevitably lead to a more accurate treatment of these still too often fatal syndromes.

Clevidipine for severe hypertension in acute heart failure: a VELOCITY trial analysis

Acute severe hypertension occurs in approximately 50% of patients with acute heart failure (AHF). Clevidipine, the latest-generation dihydropyridine calcium channel blocker, may be useful in the treatment of this patient population. The Evaluation of the Effect of Ultra-Short-Acting Clevidipine in the Treatment of Patients With Severe Hypertension (VELOCITY) trial enrolled 126 patients with systolic blood pressure (SBP) >180 mm Hg for treatment with clevidipine to a patient-specific prespecified initial target range (ITR) of SBP to be achieved within 30 minutes. Of the enrolled patients, 19 had AHF on presentation. Primary end points were the percentage in whom ITR was achieved within 30 minutes and the number whose SBP was below the ITR after 3 minutes of clevidipine infusion. Among the 19 AHF patients in VELOCITY, median time to ITR was 11.3 minutes (95% confidence interval, 7-19). ITR was reached in most patients (94%) within 30 minutes. No patient had hypotension below the ITR, and heart rate remained stable. At 18 hours, 16 of 19 patients had received continuous clevidipine infusion, and their SBP was reduced by mean of 50 mm Hg (25%) from baseline. There were no treatment-related adverse events or adverse events that led to clevidipine discontinuation. Clevidipine safely decreases SBP in AHF and does not cause unexpected hypotension. The results of this post hoc subgroup analysis suggest that clevidipine is safe, well tolerated, and efficacious in AHF patients with hypertension.

Agents with inotropic properties for the management of acute heart failure syndromes. Traditional agents and beyond

Treatment with inotropic agents is one of the most controversial topics in heart failure. Initial enthusiasm, based on strong pathophysiological rationale and apparent empirical efficacy, has been progressively limited by results of controlled trials and registries showing poorer outcomes of the patients on inotropic therapy. The use of these agents remains, however, potentially indicated in a significant proportion of patients with low cardiac output, peripheral hypoperfusion and end-organ dysfunction caused by heart failure. Limitations of inotropic therapy seem to be mainly related to their mechanisms of action entailing arrhythmogenesis, peripheral vasodilation, myocardial ischemia and damage, and possibly due to their use in patients without a clear indication, rather than to the general principle of inotropic therapy itself. This review will discuss the characteristics of the patients with a potential indication for inotropic therapy, the main data from registries and controlled trials, the mechanism of the untoward effects of these agents on outcomes and, lastly, perspectives with new agents with novel mechanisms of action.

End points for clinical trials in acute heart failure syndromes

Acute heart failure syndromes (AHFS) remain a major cause of morbidity and mortality, in part because the development of new therapies for these disorders has been marked by frequent failure and little success. The heterogeneity of current approaches to AHFS drug development, particularly with regard to end points, remains a major potential barrier to progress in the field. End points involving hemodynamic status, biomarkers, symptoms, hospital stay, end organ function, and mortality have all been employed either alone or in combination in recent randomized clinical trials in AHFS. In this review, we will discuss the various end point domains from both a clinical and a statistical perspective, summarize the wide variety of end points used in completed and ongoing AHFS studies, and suggest steps for greater standardization of end points across AHFS trials.

Relaxin for the treatment of patients with acute heart failure (Pre-RELAX-AHF): a multicentre, randomised, placebo-controlled, parallel-group, dose-finding phase IIb study

BACKGROUND

Most patients admitted for acute heart failure have normal or increase blood pressure. Relaxin is a natural human peptide that affects multiple vascular control pathways, suggesting potential mechanisms of benefit for such patients. We assessed the dose response of relaxin's effect on symptom relief, other clinical outcomes, and safety.

METHODS

In a placebo-controlled, parallel-group, dose-ranging study, 234 patients with acute heart failure, dyspnoea, congestion on chest radiograph, and increased brain natriuretic peptide (BNP) or N-terminal prohormone of BNP, mild-to-moderate renal insufficiency, and systolic blood pressure greater than 125 mm Hg were recruited from 54 sites in eight countries and enrolled within 16 h of presentation. Patients were randomly assigned, in a double-blind manner via a telephone-based interactive voice response system, to standard care plus 48-h intravenous infusion of placebo (n=62) or relaxin 10 microg/kg (n=40), 30 microg/kg (n=43), 100 microg/kg (n=39), or 250 microg/kg (n=50) per day. Several clinical endpoints were explored to assess whether intravenous relaxin should be pursued in larger studies of acute heart failure, to identify an optimum dose, and to help to assess endpoint selection and power calculations. Analysis was by modified intention to treat. This study is registered with ClinicalTrials.gov, number NCT00520806.

FINDINGS

In the modified intention-to-treat population, 61 patients were assessed in the placebo group, 40 in the relaxin 10 microg/kg per day group, 42 in the relaxin 30 microg/kg per day group, 37 in the relaxin 100 microg/kg per day group, and 49 in the relaxin 250 microg/kg per day group. Dyspnoea improved with relaxin 30 microg/kg compared with placebo, as assessed by Likert scale (17 of 42 patients [40%] moderately or markedly improved at 6 h, 12 h, and 24 h vs 14 of 61 [23%]; p=0.044) and visual analogue scale through day 14 (8214 mm x h [SD 8712] vs 4622 mm x h [9003]; p=0.053). Length of stay was 10.2 days (SD 6.1) for relaxin-treated patients versus 12.0 days (7.3) for those given placebo, and days alive out of hospital were 47.9 (10.1) versus 44.2 (14.2). Cardiovascular death or readmission due to heart or renal failure at day 60 was reduced with relaxin (2.6% [95% CI 0.4-16.8] vs 17.2% [9.6-29.6]; p=0.053). The number of serious adverse events was similar between groups.

INTERPRETATION

When given to patients with acute heart failure and normal-to-increased blood pressure, relaxin was associated with favourable relief of dyspnoea and other clinical outcomes, with acceptable safety.

Methods to evaluate the effect of ethanol on the folate analogue: fluorescein methotrexate uptake in human proximal tubular cells

Ethanol-induced folate deficiency is due to effects of ethanol on folate metabolism and absorption. We have already shown by using different methods that ethanol interferes with reabsorption of folate from the proximal tubule. In this study, we have used the folate analogue, the fluorescein methotrexate (FL-MTX), in order to evaluate effects of ethanol on FL-MTX uptake by the human proximal tubular (HPT) cells by using a confocal microscope and fluoroskan microplate reader. Since endothelins (ETs) play a major role in a number of diseases and also in the damage induced by a variety of chemicals, we have used endothelin-B (ET-B) and protein kinase-C (PKC) inhibitors to evaluate the role of endothelin in ethanol-mediated FL-MTX uptake by using fluoroskan microplate reader. Confocal microscope and fluoroskan studies reveal that cellular absorption of FL-MTX is concentration-dependent. Moreover, ethanol concentration has an impact on FL-MTX uptake. Fluoroskan studies reveal that the ethanol-induced decrease in FL-MTX uptake is reversed by adding the ET-B receptor antagonist (RES-701-1) or PKC-selective inhibitor (BIM). Thus, we can conclude that ethanol may act via ET and ET in turn may act via ET-B receptor and the PKC signaling pathway to impair FL-MTX transport.

Management of acute decompensated heart failure

Acute decompensated heart failure is the most common cause for hospitalization among patients over 65 years of age. It may result from new onset of ventricular dysfunction or, more typically, exacerbation of chronic heart failure symptoms. In-hospital mortality remains high for both systolic and diastolic forms of the disease. Therapy is largely empirical as few randomized, controlled trials have focused on this population and consensus practice guidelines are just beginning to be formulated. Treatment should be focused upon correction of volume overload, identifying potential precipitating causes, and optimizing vasodilator and beta-adrenergic blocker therapy. The majority of patients (>90%) will improve without the use of positive inotropic agents, which should be reserved for patients with refractory hypotension, cardiogenic shock, end-organ dysfunction, or failure to respond to conventional oral and/or intravenous diuretics and vasodilators. The role of aldosterone antagonists, biventricular pacing, and novel pharmacological agents including vasopressin antagonists, endothelin blockers, and calcium-sensitizing agents is also reviewed.

Epoprostenol treatment of acute pulmonary hypertension is associated with a paradoxical decrease in right ventricular contractility

OBJECTIVE

Prostacyclins have been suggested to exert positive inotropic effects which would render them particularly suitable for the treatment of right ventricular (RV) dysfunction due to acute pulmonary hypertension (PHT). Data on this subject are controversial, however, and vary with the experimental conditions. We studied the inotropic effects of epoprostenol at clinically recommended doses in an experimental model of acute PHT.

DESIGN AND SETTING

Prospective laboratory investigation in a university hospital laboratory.

SUBJECTS

Six pigs (36 +/- 7kg).

INTERVENTIONS

Pigs were instrumented with biventricular conductance catheters, a pulmonary artery (PA) flow probe, and a high-fidelity pulmonary pressure catheter. Incremental doses of epoprostenol (10, 15, 20, 30, 40ng kg(-1) min(-1)) were administered in undiseased animals and after induction of acute hypoxia-induced PHT.

MEASUREMENTS AND RESULTS

In acute PHT epoprostenol markedly reduced RV afterload (slopes of pressure-flow relationship in the PA from 7.0 +/- 0.6 to 4.2 +/- 0.7mmHg minl(-1)). This was associated with a paradoxical and dose-dependent decrease in RV contractility (slope of preload-recruitable stroke-work relationship from 3.0 +/- 0.4 to 1.6 +/- 0.2 mW s ml(-1); slope of endsystolic pressure-volume relationship from 1.5 +/- 0.3 to 0.7 +/- 0.3mmHg ml(-1)). Left ventricular contractility was reduced only at the highest dose. In undiseased animals epoprostenol did not affect vascular tone and produced a mild biventricular decrease in contractility.

CONCLUSIONS

Epoprostenol has no positive inotropic effects in vivo. In contrast, epoprostenol-induced pulmonary vasodilation in animals with acute PHT was associated with a paradoxical decrease in RV contractility. This effect is probably caused indirectly by the close coupling of RV contractility to RV afterload. However, data from normal animals suggest that mechanisms unrelated to vasodilation are also involved in the observed negative inotropic response to epoprostenol.

Vasodilators in acute heart failure

Most patients with acute heart failure present with increased left ventricular filling pressure and high or normal blood pressure; only a minority present with cardiogenic shock. In this context, therapy with vasodilators in the acute setting can improve both hemodynamics and symptoms. Vasodilators are usually given in conjunction with diuretics, although much of the acute effect of loop diuretics may be due to venodilation. Currently available agents include nitroglycerin, nitroprusside, and nesiritide. Nitroglycerin relieves pulmonary congestion primarily through direct venodilation, but may dilate coronary arteries and increase collateral blood flow at higher doses, an effect desirable in patients with ischemia. Tachyphylaxis may develop, necessitating incremental dosing. The major adverse effects of nitrates are hypotension and headache. Nitroprusside is a balanced arterial and venous vasodilator with a very short half-life, facilitating rapid titration. Afterload reduction lowers blood pressure and can increase stroke volume. The major complications of nitroprusside therapy are hypotension, and toxicity from accumulation of cyanide or thiocyanate, usually in patients with renal insufficiency treated for more than 24 h. Nesiritide, a recombinant form of human B-type natriuretic peptide (BNP), is a venous and arterial vasodilator that may also potentiate the effect of concomitant diuretics. Hypotension is the most common side effect. In addition, meta-analyses have suggested that nesiritide may worsen renal function and decrease survival at 30 days compared to conventional therapies. Resolution of these concerns awaits completion of appropriately powered prospective clinical trials. Angiotensin-converting enzyme (ACE) inhibitors have vasodilatory effects, but intravenous infusion of enalapril within 24 h of ischemic chest pain is not recommended. Oral ACE inhibition may be used to reduce afterload in other settings if blood pressure permits. Use of calcium antagonists in acute heart failure is not recommended.

Right ventricular failure complicating heart failure: pathophysiology, significance, and management strategies

Right heart failure most commonly results from the complication of left heart failure (systolic or nonsystolic dysfunction) or pulmonary hypertension. Over the past decade, greater attention has been paid to the role of right ventricular failure in the morbidity and mortality associated with cardiomyopathy and pulmonary hypertension. The right ventricle is distinct from the left ventricle not only in its spatial localization, but also in its response to increased afterload and signaling mechanisms. This article discusses the role of right ventricular failure in the setting of heart failure as well as the clinical diagnosis and management of right ventricular failure.

Genetic engineering and therapy for inherited and acquired cardiomyopathies

The cardiac myofilaments consist of a highly ordered assembly of proteins that collectively generate force in a calcium-dependent manner. Defects in myofilament function and its regulation have been implicated in various forms of acquired and inherited human heart disease. For example, during cardiac ischemia, cardiac myocyte contractile performance is dramatically downregulated due in part to a reduced sensitivity of the myofilaments to calcium under acidic pH conditions. Over the last several years, the thin filament regulatory protein, troponin I, has been identified as an important mediator of this response. Mutations in troponin I and other sarcomere genes are also linked to several distinct inherited cardiomyopathic phenotypes, including hypertrophic, dilated, and restrictive cardiomyopathies. With the cardiac sarcomere emerging as a central player for such a diverse array of human heart diseases, genetic-based strategies that target the myofilament will likely have broad therapeutic potential. The development of safe vector systems for efficient gene delivery will be a critical hurdle to overcome before these types of therapies can be successfully applied. Nonetheless, studies focusing on the principles of acute genetic engineering of the sarcomere hold value as they lay the essential foundation on which to build potential gene-based therapies for heart disease.

Advances in the treatment of acute decompensated heart failure in the elderly

Acute decompensated heart failure is the leading cause of hospitalization in older adults, and more than half of all patients admitted with this condition are over 75 years of age. In addition, hospital mortality is threefold higher in patients over 75 years of age compared with younger patients. This article reviews the pathophysiology, clinical features and management of acute heart failure in older adults, highlighting recent advances in the field. It is anticipated that over the next 5–10 years, new approaches to the treatment of acute decompensated heart failure will become available. Nonetheless, additional research is required to develop more effective strategies for the prevention and management of both acute and chronic heart failure in our rapidly growing elderly population.

Nesiritide: a reappraisal of efficacy and safety

The treatment of acute decompensated heart failure (ADHF) remains a therapeutic challenge. Nesiritide was approved by the FDA in 2001 for the treatment of patients with ADHF who have dyspnea at rest or with minimal exertion. Although widely adopted for the treatment of ADHF due to its ability to decrease ventricular filling pressures and to provide mild symptomatic benefit, recent analyses have suggested that nesiritide worsens renal function and increases mortality. Although some discount these analyses that demonstrate the potential dangers of nesiritide, others have stated that its use at the present time must be weighed against the possibility of worse outcomes. A large outcomes trial in patients with ADHF would help clarify the role of nesiritide.

Pathophysiologic targets in the early phase of acute heart failure syndromes

An episode of acute heart failure syndromes (AHFS) can be defined as a rapid or gradual onset of signs and symptoms of heart failure (HF) in hospital admission and can arise from a variety of pathophysiologic mechanisms. This article reviews our current understanding of the pathophysiology of AHFS in order to identify potential therapeutic targets. Most patients with AHFS present with either normal systolic blood pressure or elevated blood pressure. Patients who present with elevated systolic blood pressure usually have pulmonary congestion and a relatively preserved left ventricular ejection fraction (LVEF), and have symptoms that typically develop abruptly, these patients often are elderly women. Patients with normal systolic blood pressure presenting with systemic congestion and reduced LVEF are usually younger, with a history of chronic HF, and have symptoms that develop gradually over days or weeks. Accordingly, most episodes of AHFS can be classified as either "vascular" failure or "cardiac" failure. In addition to the abnormal hemodynamics (increase in pulmonary capillary wedge pressure and/or decrease in cardiac output) that characterize patients with AHFS, myocardial injury--which may be related to a decrease in coronary perfusion and/or further activation of neurohormones and renal dysfunction (ie, the cardiorenal syndrome)--probably contributes to short-term and post-discharge cardiac events. Patients with AHFS also have significant cardiac and non-cardiac underlying conditions that contribute to the pathogenesis of AHFS, including coronary artery disease (ischemia, hibernating myocardium, and endothelial dysfunction), hypertension, atrial fibrillation, and type 2 diabetes mellitus. The goals of therapy for AHFS should be not only to improve symptoms and hemodynamics, but also to preserve or improve renal function and prevent myocardial damage.