Levosimendan improves diastolic and systolic function in failing human myocardium

Familial dilated cardiomyopathy in a child: a case report

BACKGROUND

Dilated cardiomyopathy (DCM) commonly leads to heart failure (HF) and represents the most common indication for cardiac transplantation in the pediatric population. Clinical manifestations of DCM are mainly the symptoms of heart failure; it is diagnosed by EKG, chest x-ray and echocardiography. For the idiopathic and familial diseases cases of DCM, there are no definite guidelines for treatment in children as they are treated for prognostic improvement.

CASE PRESENTATION

We report the case of a 2-year-old girl diagnosed with dilated cardiomyopathy associated with homozygous mutation in the Myosin Light Chain 3 gene admitted for edema in lower extremities, muscle weakness, lethargy and vomiting, and she was found to be in cardiogenic shock. Chest x-ray showed cardiomegaly and EKG showed first degree atrioventricular block. Echocardiogram showed severe biventricular systolic and diastolic dysfunction. After 70 days of hospitalization, the patient went into cardiac arrest with cessation of electrical and mechanical activity of the heart, despite cardiopulmonary resuscitative efforts.

CONCLUSION

Although rare, pediatric DCM carries a high risk of morbidity and mortality and a lack of curative therapy.

The Impact of Inotropes and Vasopressors on Cerebral Oxygenation in Patients with Traumatic Brain Injury and Subarachnoid Hemorrhage: A Narrative Review

Traumatic brain injury (TBI) and subarachnoid hemorrhage (SAH) are critical neurological conditions that necessitate specialized care in the Intensive Care Unit (ICU). Managing cerebral perfusion pressure (CPP) and mean arterial pressure (MAP) is of primary importance in these patients. To maintain targeted MAP and CPP, vasopressors and/or inotropes are commonly used. However, their effects on cerebral oxygenation are not fully understood. The aim of this review is to provide an up-to date review regarding the current uses and pathophysiological issues related to the use of vasopressors and inotropes in TBI and SAH patients. According to our findings, despite achieving similar hemodynamic parameters and CPP, the effects of various vasopressors and inotropes on cerebral oxygenation, local CBF and metabolism are heterogeneous. Therefore, a more accurate understanding of the cerebral activity of these medications is crucial for optimizing patient management in the ICU setting.

Levosimendan or milrinone for right ventricular inotropic treatment?-A secondary analysis of a randomized trial

BACKGROUND

The aim of the present study was to compare the effects of milrinone and levosimendan on right ventricular (RV) inotropy and lusitropy in patients after aortic valve replacement (AVR) for aortic stenosis, a procedure in which an abnormal postoperative RV function may be seen.

METHODS

In a prospective, blinded trial, 31 patients were randomized to receive either milrinone (0.4 and 0.8 µg/kg/min, n = 16) or levosimendan (0.1 and 0.2 µg/kg/min, n = 15) after AVR for aortic stenosis. RV performance, afterload (pulmonary arterial elastance), RV strain, systolic (SR-S) and early diastolic (SR-E) strain rate were measured by pulmonary artery thermodilution catheterization and transoesophageal two-dimensional speckle tracking echocardiography. To circumvent the indirect effects of inodilator-induced hemodynamic changes on RV systolic and diastolic deformation, pulmonary arterial elastance, central venous pressure and heart rate were maintained constant by atrial pacing, plasma volume expansion with colloids and phenylephrine-induced vasoconstriction during treatment with the inotropes.

RESULTS

A dose-dependent increase in stroke volume index and cardiac index by approximately 20% were seen with both agents at the highest doses, with no difference between groups (P = .792 and 0.744, respectively). In both groups, RV strain and SR-S dose-dependently increased by 20% and 15%-19%, respectively, at the highest doses (P = .742 and 0.259, respectively) with no difference between groups. SR-E improved by both agents 20%-24% at the highest dose with no difference between groups (P = .714).

CONCLUSIONS

The direct RV inotropic and lusitropic effects of levosimendan and milrinone were comparable at clinically relevant infusion rates.

[Acute perioperative right heart insufficiency : Diagnostics and treatment]

Acute right heart failure is often overlooked as a cause of cardiopulmonary insufficiency. The various pathologies underlying right heart failure at the level of afterload, preload and contractility, make rapid, targeted diagnostics necessary. In addition to clinical symptoms and laboratory chemical parameters, echocardiography in particular is relevant for making a diagnosis. Symptomatic treatment of the endangered patient is essential. The focus is on a reduction of right ventricular pressure and afterload, a correction of systemic hypotension and positive inotropic support of the right ventricle. Mechanical organ replacement and support procedures are increasingly being used in the case of persistent right heart failure and expand the possibilities for treatment. Decisive for the prognosis is a causal treatment adapted to the underlying triggering disease.

Assessment of Genotoxicity of Levosimendan in Human Cultured Lymphocytes

BACKGROUND AND OBJECTIVE

Levosimendan is a positive inotropic and a vasodilator agent with pleotropic characteristics that include antioxidation, anti-inflammation and smooth muscle vasodilation.

METHODS

In this study, the effects of levosimendan (0, 0.1, 1, 10, and 20 µg/ml) on oxidative DNA damage and sister-chromatid exchanges (SCEs) were evaluated in human cultured lymphocytes.

RESULTS

The results showed that levosimendan increased the frequency of SCEs in all examined concentrations (P<0.01) except for 0.1 µg/ml. On the other hand, levosimendan did not induce oxidative DNA damage as measured by the 8-OHdG biomarker (P > 0.05). In addition, neither mitotic arrest nor proliferation index was affected by levosimendan at all examined doses (P > 0.05).

CONCLUSION

In conclusion, levosimendan might be associated with increases in sister-chromatid exchanges in cultured human lymphocytes. In vivo studies are required to confirm the present findings.

Effect of Levosimendan Compared to Conventional Inotropic Agents on Hemodynamics and Outcome in Patient with Poor LV Function Undergoing Cardiac Surgery

BACKGROUND

Patients undergoing heart surgery involving cardiopulmonary bypass (CPB) experience global myocardial ischemia with subsequent reperfusion which, despite cardioplegic protection, may result in different degrees of transient ventricular dysfunction. Levosimendan is a "calcium sensitisers", it improves myocardial contractility by sensitising troponin C to calcium without increasing myocardial oxygen consumption and without impairing relaxation and diastolic function.

AIM

To evaluate the adding effect of a calcium sensitiser (levosimendan) compared to the conventional inotropic and vasoactive agent used in the patient with poor left ventricular function undergoing cardiac surgery on different measured hemodynamic variables and the effect on the outcome.

METHODS

It is prospective observational studies were patients were divided into 2 groups of 30 patients each. The first Group received conventional inotropic and vasoactive treatment at different doses, while the other group received levosimendan additionally at a loading dose of 6-12mic/kg according to mean arterial pressure over 0.5 hr followed by 24 hrs infusion at 0.05 to 0.2 mic/kg/min. Hemodynamic data were collected at the end and 30 minutes after CPB, after that at 6, 12, 24, and 36 hours post CPB. Mean arterial pressure (MAP), central venous pressure (CVP), heart rate (HR), mixed venous saturation (Svo2), and base deficit (BD) were measured.

RESULTS

Levosimendan had significantly improved postoperative hemodynamic values as in the mixed venous pressure at different times postoperative (p < 0.05), also the base deficit at different times postoperative (p < 0.05), while there was a significant reduction in systemic vascular resistance as decreased mean arterial pressure in levosimendan group compared to conventional group at 6hrs postoperative mean 77.50 ± 10.81 vs 83.73 ± 10.81 with (p = 0.029), and at 12 hrs postoperative mean 77.37 ± 10.10vs 84.23 ± 13.81 with (p = 0.032), and there was no significant difference in heart rate at different times postoperative between both groups (p > 0.05), while there was no significant effect on mortality between both groups (p = 0.781).

CONCLUSION

Levosimendan had improved hemodynamic parameters significantly with no effect on mortality compared to conventional inotropic agents in a patient with poor left ventricular function undergoing cardiac surgery.

Inotropic and lusitropic effects of levosimendan and milrinone assessed by strain echocardiography-A randomised trial

BACKGROUND

We compared the direct inotropic and lusitropic effects of two inodilators, milrinone and levosimendan in patients after aortic valve replacement for aortic stenosis.

METHODS

In this randomised, blinded study, 31 patients with normal LV function, were randomised to either levosimendan (0.1 and 0.2 μg/kg/min, n = 15) or milrinone (0.4 and 0.8 μg/kg/min, n = 16) after aortic valve replacement. The effects on LV performance, LV strain, systolic (SR-S) and early diastolic (SR-E) strain rate were assessed by a pulmonary artery catheter and transoesophageal two-dimensional speckle tracking echocardiography of the LV inferior wall. To circumvent the inodilator-induced hemodynamic changes on LV systolic and diastolic deformation, central venous pressure (CVP), systolic artery pressure (SAP), and heart rate were maintained constant by colloid infusion, phenylephrine-induced vasoconstriction and atrial pacing, respectively, during drug infusion.

RESULTS

Both inotropic agents induced a dose-dependent increase in cardiac index and stroke volume index by approximately 20% at the highest infusion rates with no differences between groups (P = .139 and .249, respectively). CVP, pulmonary capillary wedge pressure, SAP and heart rate were maintained constant in both groups. LV strain and SR-S increased with both agents, dose-dependently, by 17%-18% and 25%-30%, respectively, at the highest infusion rates, with no difference between groups (P = .434 and .284, respectively). Both agents improved early LV relaxation with no differences between groups (P = .637). At the higher doses, both agents increased SR-E by 30%.

CONCLUSIONS

At clinically relevant infusion rates and a certain increase in LV performance the direct inotropic and lusitropic of milrinone and levosimendan were comparable.

Highly variable contractile performance correlates with myocyte content in trabeculae from failing human hearts

Heart failure (HF) is defined by compromised contractile function and is associated with changes in excitation-contraction (EC) coupling and cardiomyocyte organisation. Tissue level changes often include fibrosis, while changes within cardiomyocytes often affect structures critical to EC coupling, including the ryanodine receptor (RyR), the associated protein junctophilin-2 (JPH2) and the transverse tubular system architecture. Using a novel approach, we aimed to directly correlate the influence of structural alterations with force development in ventricular trabeculae from failing human hearts. Trabeculae were excised from explanted human hearts in end-stage failure and immediately subjected to force measurements. Following functional experiments, each trabecula was fixed, sectioned and immuno-stained for structural investigations. Peak stress was highly variable between trabeculae from both within and between failing hearts and was strongly correlated with the cross-sectional area occupied by myocytes (MCSA), rather than total trabecula cross-sectional area. At the cellular level, myocytes exhibited extensive microtubule densification which was linked via JPH2 to time-to-peak stress. Trabeculae fractional MCSA variability was much higher than that in adjacent free wall samples. Together, these findings identify several structural parameters implicated in functional impairment in human HF and highlight the structural variability of ventricular trabeculae which should be considered when interpreting functional data.

Decongestive effects of levosimendan in cardiogenic shock induced by postpartum cardiomyopathy

BACKGROUND

Catecholamines and/or levosimendan have been proposed for haemodynamic restoration during cardiogenic shock (CS). In CS induced by post-partum cardiomyopathy (PPCM), levosimendan might be particularly favourable. The aim of this study was to evaluate the haemodynamic and echocardiographic effects of levosimendan in patients with CS, in particular in patients with PPCM-induced CS.

METHODS

Twenty-eight patients with refractory CS were retrospectively included in the study. Among them, a cohort of 8 women with PPCM-induced CS was included. All patients were treated with levosimendan (loading dose followed by a continuous infusion for 24 h) and were invasively monitored, including a pulmonary artery catheter, for 48hours. Echocardiographic measurements were performed at baseline and during follow-up.

RESULTS

Significant improvements in haemodynamic parameters were observed 48 h after starting levosimendan. The cardiac index increased (+1.2±0.6L/min, P<0.001) and filling pressures decreased (pulmonary artery occlusion pressure, PAOP: -11.2±4.3mmHg, P<0.001; right-atrial pressure, RAP: -6.1±4.9mmHg, P<0.001). The left ventricular ejection fraction was significantly higher at 48 h compared to baseline (38% [34-46%] versus 27% [22-30%], P<0.001). Despite similar characteristics at baseline, in the subgroup of patients with PPCM, more profound decongestive effects at 48hours were observed: PAOP (13±2 versus 17±4mmHg, P=0.007) and RAP (12±4 versus 17±4mmHg, P=0.006) were significantly lower in the PPCM subgroup compared to the non-PPCM subgroup.

CONCLUSIONS

Haemodynamics and left-ventricular ejection fraction rapidly improved after treatment with levosimendan. In patients with PPCM-induced CS, a more profound reduction of congestion was observed.

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.

The role of Levosimendan in cardiopulmonary resuscitation

Although initial resuscitation from cardiac arrest (CA) has increased over the past years, long term survival rates remain dismal. Epinephrine is the vasopressor of choice in the treatment of CA. However, its efficacy has been questioned, as it has no apparent benefits for long-term survival or favorable neurologic outcome. Levosimendan is an inodilator with cardioprotective and neuroprotective effects. Several studies suggest that it is associated with increased rates of return of spontaneous circulation as well as improved post-resuscitation myocardial function and neurological outcome. The purpose of this article is to review the properties of Levosimendan during cardiopulmonary resuscitation (CPR) and also to summarize existing evidence regarding the use of Levosimendan in the treatment of CA.

Levosimendan: Implications for Clinicians

Levosimendan is a novel calcium sensitizing agent in development for the treatment of acute and chronic heart failure. The agent increases myocardial force without increasing myocyte calcium concentrations, thus reducing the possibility for myocardial necrosis. In addition, the agent also causes vasodilation of coronary and peripheral vessels to improve coronary blood flow and reduce afterload. The short half-life is a benefit for intravenous administration but could be problematic for the drug's use in chronic heart failure. The risk of the development of arrhythmias from levosimendan appears small secondary to an increase in the QTc interval of 15 msec but needs to be evaluated in light of the ability of levosimendan to open adenosine triphosphate (ATP)-sensitive potassium channels. In addition, the agent has not been studied in patients with additional risks for torsades de pointes. Levosimendan has been shown to have beneficial survival effects in several populations; its use improves patient outcomes relative to the standard of care and has the potential to reduce hospital costs associated with heart failure.

Levosimendan restores the positive force-frequency relation in heart failure

Frequency potentiation of contractile function is a major mechanism of the increase in myocardial performance during exercise. In heart failure (HF), this positive force-frequency relation is impaired, and the abnormal left ventricular (LV)-arterial coupling is exacerbated by tachycardia. A myofilament Ca(2+) sensitizer, levosimendan, has been shown to improve exercise tolerance in HF. This may be due to its beneficial actions on the force-frequency relation and LV-arterial coupling (end-systolic elastance/arterial elastance, E(ES)/E(A)). We assessed the effects of therapeutic doses of levosimendan on the force-frequency relation and E(ES)/E(A) in nine conscious dogs after pacing-induced HF using pressure-volume analysis. Before HF, pacing tachycardia increased E(ES), shortened τ, and did not impair E(ES)/E(A) and mechanical efficiency (stroke work/pressure-volume area, SW/PVA). In contrast, after HF, pacing at 140, 160, 180, and 200 beat/min (bpm) produced smaller a increase of E(ES) or less shortening of τ, whereas E(ES)/E(A) (from 0.56 at baseline to 0.42 at 200 bpm) and SW/PVA (from 0.52 at baseline to 0.43 at 200 bpm) progressively decreased. With levosimendan, basal E(ES) increased 27% (6.2 mmHg/ml), τ decreased 11% (40.8 ms), E(ES)/E(A) increased 34% (0.75), and SW/PVA improved by 15% (0.60). During tachycardia, E(ES) further increased by 23%, 37%, 68%, and 89%; τ decreased by 9%, 12%, 15%, and 17%; and E(ES)/E(A) was augmented by 11%, 16%, 31%, and 33%, incrementally, with pacing rate. SW/PVA was improved (0.61 to 0.64). In conclusion, in HF, treatment with levosimendan restores the normal positive LV systolic and diastolic force-frequency relation and prevents tachycardia-induced adverse effect on LV-arterial coupling and mechanical efficiency.

Sex-specific modification of progesterone receptor expression by 17β-oestradiol in human cardiac tissues

Background

Although circulating levels of sexual hormones in elderly men and women are low and quite similar, the adaptation of the elderly heart to stress differs between the sexes. We have hypothesized that the effects of sexual hormones in the heart may differ in men and women. Here, we assessed whether 17β-oestradiol regulates gene expression in the human heart in a sex-dependent manner. We selected the progesterone receptor as a well studied 17β-oestradiol target that may be pathologically linked to cardiac remodelling.

Methods

In order to assess the ex vivo effects of 17β-oestradiol in intact human cardiac tissues, we developed a 24-h model for the culture of human atrial myocardium. We verified tissue viability after 24 h in culture with two standard assays to determine the degree of apoptosis and metabolic activity of cardiac tissues. Progesterone receptor mRNA and protein level were measured after 24-h treatment of tissues with 17β-oestradiol. Statistical analysis was performed by the Mann-Whitney U test and two-way ANOVA.

Results

We established a tissue culture model that allows for the study of viable human cardiac tissue over a 24-h period. After 24 h, cultured cardiac tissues revealed low apoptosis, retained their metabolic activity and, therefore, remained viable. Treatment with 17β-oestradiol led to an induction of the progesterone receptor mRNA level in female (P = 0.001) but not in male tissues. Similarly, there was an increase in the level of progesterone receptor protein in female tissues (P = 0.03), while a decreasing trend was observed in male tissues (P = 0.079) exposed to 17β-oestradiol.

Conclusions

Our novel finding may offer a molecular explanation for the sex-specific differences observed in cardiac remodelling. The culture model we established for human cardiac tissue will facilitate the study of cellular processes in health and disease and will be of use for pharmacological testing.

Calcium sensitivity, force frequency relationship and cardiac troponin I: critical role of PKA and PKC phosphorylation sites

Transgenic models with pseudo phosphorylation mutants of troponin I, PKA sites at Ser 22 and 23 (cTnIDD(22,23) mice) or PKC sites at Ser 42 and 44 (cTnIAD(22,23)DD(42,44)) displayed differential force-frequency relationships and afterload relaxation delay in vivo. We hypothesized that cTnI PKA and PKC phosphomimics impact cardiac muscle rate-related developed twitch force and relaxation kinetics in opposite directions. cTnIDD(22,23) transgenic mice produce a force frequency relationship (FFR) equivalent to control NTG albeit at lower peak [Ca(2+)](i), while cTnIAD(22,23)DD(42,44) TG mice had a flat FFR with normal peak systolic [Ca(2+)](i), thus suggestive of diminished responsiveness to [Ca(2+)](i) at higher frequencies. Force-[Ca(2+)](i) hysteresis analysis revealed that cTnIDD(22,23) mice have a combined enhanced myofilament calcium peak response with an enhanced slope of force development and decline per unit of [Ca(2+)](i), whereas cTnIAD(22,23)DD(42,44) transgenic mice showed the opposite. The computational ECME model predicts that the TG lines may be distinct from each other due to different rate constants for association/dissociation of Ca(2+) at the regulatory site of cTnC. Our data indicate that cTnI phosphorylation at PKA sites plays a critical role in the FFR by increasing relative myofilament responsiveness, and results in a distinctive transition between activation and relaxation, as displayed by force-[Ca(2+)](i) hysteresis loops. These findings may have important implications for understanding the specific contribution of cTnI to beta-adrenergic inotropy and lusitropy and to adverse contractile effects of PKC activation, which is relevant during heart failure development.

Review article: inotrope and vasopressor use in the emergency department

Shock is a common presentation to the ED, with the incidence of septic shock increasing in Australasia over the last decade. The choice of inotropic agent is likely dependent on previous experience and local practices of the emergency and other critical care departments. The relatively short duration of stay in the ED before transfer leaves little room for evaluating the appropriateness of and response to the agent chosen. Delays in transfer to inpatient facilities means that patients receive advanced critical care within the ED for longer, requiring initiation and titration of vasoactive agents in the ED. This article discusses the general concepts of shock and the indicators for inotrope and vasopressor use, revises the various agents available and reviews the current evidence for their use.

[Role of Levosimendan in intensive care treatment of myocardial insufficiency]

Levosimendan is a calcium sensitizer that is currently in the focus of intensive care medicine because it may be superior to standard inotropic agents in the treatment of acute myocardial insufficiency. The effects of levosimendan mainly depend on three predominant mechanisms: 1) positive inotropic effect by increasing the sensitivity of cardiac myofilaments to calcium ions, 2) vasodilatory effect by stimulation of adenosine triphosphate-sensitive potassium channels and 3) inhibition of phosphodiesterase-III. In a large number of experimental and clinical studies further possible indications for levosimendan have been described, e.g. cardioprotection during ischemia, cardiogenic shock, septic myocardial insufficiency and pulmonary hypertension. This review article critically summarizes the current scientific and clinical knowledge about levosimendan, its pharmacologic characteristics, mechanisms of action as well as indications and potential risks.

Levosimendan improves the initial outcome of cardiopulmonary resuscitation in a swine model of cardiac arrest

BACKGROUND

Cardiac arrest remains the leading cause of death in Western societies. Advanced Life Support guidelines propose epinephrine (adrenaline) for its treatment. The aim of this study was to assess whether a calcium sensitizer agent, such as levosimendan, administered in combination with epinephrine during cardiopulmonary resuscitation, would improve the initial resuscitation success.

METHODS

Ventricular fibrillation was induced in 20 Landrace/Large-White piglets, and left untreated for 8 min. Resuscitation was then attempted with precordial compressions, mechanical ventilation and electrical defibrillation. The animals were randomized into two groups (10 animals each): animals in Group A received saline as placebo (10 ml dilution, bolus) + epinephrine (0.02 mg/kg), and animals in Group B received levosimendan (0.012 mg/kg/10 ml dilution, bolus) + epinephrine (0.02 mg/kg) during cardiopulmonary resuscitation. Electrical defibrillation was attempted after 10 min of ventricular fibrillation.

RESULTS

Four animals in Group A showed restoration of spontaneous circulation and 10 in Group B (P = 0.011). The coronary perfusion pressure, saturation of peripheral oxygenation and brain regional oxygen saturation were significantly higher during cardiopulmonary resuscitation in Group B.

CONCLUSIONS

A calcium sensitizer agent, when administered during cardiopulmonary resuscitation, significantly improves initial resuscitation success and increases coronary perfusion pressure during cardiopulmonary resuscitation.

A 6-Month Follow-up of Intermittent Levosimendan Administration Effect on Systolic Function, Specific Activity Questionnaire, and Arrhythmia in Advanced Heart Failure

BACKGROUND

Levosimendan (LS) improves cardiac contractility without increasing myocardial oxygen demand. We administrated LS on a monthly intermittent 24-hour protocol and evaluated the clinical effect after 6 months in a randomized, open, prospective study.

METHODS AND RESULTS

Fifty patients (age 45-65 years) with LV systolic dysfunction and New York Heart Association (NYHA) III or IV were randomized in 2 groups. LS group (n = 25) was compared with a control group (n = 25) matched for sex, age, and NYHA class. LS was given monthly on a 24-hour intravenous protocol for 6 months. Patients were evaluated by specific activity questionnaire (SAQ) and echocardiography (ECHO) before and 3 to 5 days after last drug administration, whereas 24-hour Holter recording was performed before and during last drug administration. Patients in LS and control group had same baseline SAQ, ECHO, and Holter parameters. At the end of the study, a larger proportion of patients in the levosimendan group reported improvement in symptoms (dyspnea and fatigue) (65% versus 20% in controls, P < .01). After 6 months, the LS group had a significant increase in LV ejection fraction versus controls (28 +/- 7 versus 21 +/- 4 %, P = .003), LV shortening fraction (15 +/- 3 versus 11 +/- 3 %, P = .006) and a decrease in mitral regurgitation (1.5 +/- 0.8 versus 2.7 +/- 0.6, P = .0001). There was no increase in supraventricular or ventricular beats or supraventricular tachycardia and VT episodes in LS group, compared with controls. Two patients from the LS group died in the 6-month follow-up period, compared with 8 patients in the control group (8% versus 32%, P < .05).

CONCLUSIONS

A 6-month intermittent LS treatment in patients with decompensated advanced heart failure improved symptoms and LV systolic function.

Frequency-dependent myofilament Ca2+ desensitization in failing rat myocardium

The positive force-frequency relation, one of the key factors modulating performance of healthy myocardium, has been attributed to an increased Ca(2+) influx per unit of time. In failing hearts, a blunted, flat or negative force-frequency relation has been found. In healthy and failing hearts frequency-dependent alterations in Ca(2+) sensitivity of the myofilaments, related to different phosphorylation levels of contractile proteins, could contribute to this process. Therefore, the frequency dependency of force, intracellular free Ca(2+) ([Ca(2+)](i)), Ca(2+) sensitivity and contractile protein phosphorylation were determined in control and monocrotaline-treated, failing rat hearts. An increase in frequency from 0.5 to 6 Hz resulted in an increase in force in control (14.3 +/- 3.0 mN mm(-2)) and a decrease in force in failing trabeculae (9.4 +/- 3.2 mN mm(-2)), whereas in both groups the amplitude of [Ca(2+)](i) transient increased. In permeabilized cardiomyocytes, isolated from control hearts paced at 0 and 9 Hz, Ca(2+) sensitivity remained constant with frequency (pCa(50): 5.55 +/- 0.02 and 5.58 +/- 0.01, respectively, P>0.05), whereas in cardiomyocytes from failing hearts Ca(2+) sensitivity decreased with frequency (pCa(50): 5.62 +/- 0.01 and 5.57 +/- 0.01, respectively, P<0.05). After incubation of the cardiomyocytes with protein kinase A (PKA) this frequency dependency of Ca(2+) sensitivity was abolished. Troponin I (TnI) and myosin light chain 2 (MLC2) phosphorylation remained constant in control hearts but both increased with frequency in failing hearts. In conclusion, in heart failure frequency-dependent myofilament Ca(2+) desensitization, through increased TnI phosphorylation, contributes to the negative force-frequency relation and is counteracted by a frequency-dependent MLC2 phosphorylation. We propose a novel role for PKC-mediated TnI phosphorylation in modulating the force-frequency relation.

A review of levosimendan in the treatment of heart failure

Heart failure is a relatively important public health problem due to its increasing incidence, poor prognosis, and frequent need of re-hospitalization. Intravenous positive inotropic agents play an important role in treating acute decompensation of patients with heart failure due to left ventricular systolic dysfunction. Although frequently used, the inotropic agents β-adrenergic agonists and phosphodiesterase inhibitors seem effective for improving symptoms in the short term; it has been shown that they increase morbidity and mortality by elevating intracellular cyclic adenosine monophosphate (cAMP) and calcium levels. Levosimendan is a new positive inotropic agent having ATP-dependent potassium-channel-opening and calcium-sensitizing effects. In studies on its effects without increasing intracellular calcium concentrations and on its effects that depend on available intracellular calcium levels, it has been shown to have favorable characteristics different from those of current inotropic agents, which exert their effects by increasing calcium concentrations. This study aims to review other important studies about levosimendan by revealing the underlying mechanisms of its activity, efficiency, and safety.

A phase 1-2 dose-escalating study evaluating the safety and tolerability of istaroxime and specific effects on electrocardiographic and hemodynamic parameters in patients with chronic heart failure with reduced systolic function

Istaroxime (PST2744) is a luso-inotrope that stimulates the sarcoplasmic reticulum calcium adenosine triphosphatase isoform 2a without chronotropic effects. Additionally, it has beneficial effects on myocardial energetics. This phase 1-2 clinical trial in patients with chronic stable heart failure (HF) is the first evaluation of istaroxime in humans. Three cohorts of 6 patients each were exposed to 4 sequentially increasing 1-hour infusions with a random placebo. Doses were 0.005-5.0 micro/kg per min. Safety and hemodynamics were evaluated by impedance cardiography, digital Holter recorder, and electrocardiography. Pharmacokinetic data were obtained for 1 hour during treatment and for 6 hours after dosing. The mean age was 53+/-7 years, and the mean left ventricular ejection fraction was 0.27+/-0.08. Impedance cardiography demonstrated enhanced contractility as measured by the acceleration index, left cardiac work index, cardiac index, and pulse pressure at doses>or=1 micro/kg per min, with evidence of activity at doses of 0.5 micro/kg per min. Istaroxime shortened QTc. After infusion, the hemodynamic effect rapidly dissipated over 1-2 hours. Istaroxime was pharmacologically active and well tolerated at doses up to 3.33 micro/kg per min. Side effects were related to gastrointestinal symptoms and injection site pain at higher doses, which dissipated within minutes after the infusion ended. Ventricular ectopy was not altered. This study suggests that istaroxime is potentially useful in the treatment of HF and may offer a unique treatment for systolic and/or diastolic dysfunction. Additional studies are under way to further define its utility in acute HF.

Effects of levosimendan versus dobutamine on pressure load-induced right ventricular failure*

OBJECTIVE

A transient increase in pulmonary arterial (PA) pressure can persistently depress right ventricular (RV) contractility. We investigated the effects of dobutamine and levosimendan on RV-PA coupling in this model of RV failure.

DESIGN

Prospective, controlled, randomized animal study.

SETTING

University research laboratory.

SUBJECTS

Fifteen anesthetized dogs.

INTERVENTIONS

Transient (90-min) PA constriction to induce persistent RV failure. Random assignment to dobutamine 5 and 10 microg/kg/min or levosimendan 12 microg/kg for 10 mins followed by 0.1 and 0.2 microg/kg/min.

MEASUREMENTS AND MAIN RESULTS

We measured PA distal resistance and proximal elastance by pressure-flow relationships and vascular impedance. We measured RV contractility by the end-systolic pressure-volume relationship (Ees), PA effective elastance by the end-diastolic to end-systolic relationship (Ea), and RV-PA coupling efficiency by the Ees/Ea ratio. PA constriction persistently increased PA resistance and elastance, increased Ea from 0.95 +/- 0.07 to 3.01 +/- 0.28 mm Hg/mL, decreased Ees from 1.17 +/- 0.09 to 0.58 +/- 0.07 mm Hg/mL, and decreased Ees/Ea from 1.26 +/- 0.09 to 0.22 +/- 0.03 (p < .05). Dobutamine did not affect pulmonary hemodynamics, markedly increased RV contractility, and improved RV-PA coupling. Levosimendan decreased PA resistance and elastance, increased RV contractility, and restored RV-PA coupling. Compared with dobutamine, levosimendan decreased RV afterload and therefore better restored RV-PA coupling at similar inotropic state.

CONCLUSIONS

A transient increase in PA pressure persistently worsens PA hemodynamics, RV contractility, RV-PA coupling, and cardiac output. Levosimendan restores RV-PA coupling better than dobutamine because of similar inotropic effects and additional pulmonary vasodilatory effects.

Myocardial regulatory proteins and heart failure

Cardiac troponin T (cTnT) and cardiac troponin I (cTnI) are considered to be the most specific and sensitive biochemical markers of myocardial damage. Troponins have been studied in a wide range of clinical settings, including heart failure; however, there are few data on the role of regulatory proteins in the pathogenesis of heart failure, although a few interesting hypotheses have been proposed. A considerable body of evidence favours the view that alteration of the myocardial thin filament is the primary event leading to defective contractility of the failing myocardium, while the changes in Ca(2+) handling are a compensatory response. A better understanding of the role of regulatory proteins under different physiological and pathological conditions could lead to new therapeutic approaches in heart failure. Recently, calcium sensitisation has been proposed as a novel method by which cardiac performance may be enhanced via an increase in the affinity of troponin C for calcium but without affecting intracellular calcium concentration. To date, the only calcium sensitizer used in clinical practice is levosimendan.

Pharmacological Mechanisms Contributing to the Clinical Efficacy of Levosimendan

Acute decompensation of chronic heart failure is a direct life-threatening situation with short-term mortality approaching 30%. A number of maladaptive changes are amplified within the cardiovascular system during the progression of chronic heart failure that makes the decompensation phase difficult to handle. Levosimendan is a new Ca2+-sensitizer for the treatment of acutely decompensated heart failure that has proved to be effective during the decompensation of chronic heart failure and acute myocardial infarction. Levosimendan differs from other cardiotonic agents that are used for acute heart failure in that it utilizes a unique dual mechanism of action: Ca2+-sensitization through binding to troponin C in the myocardium, and the opening of ATP-sensitive K+ channels in vascular smooth muscle. In general, these mechanisms evoke positive inotropy and vasodilation. Clinical studies suggested long-term benefits on mortality following short-term administration. It may, therefore, be inferred that levosimendan has additional effects on the cardiovascular system that are responsible for the prolongation of survival. Results of preclinical and clinical investigations suggest that the combination of levosimendan-induced cardiac and vascular changes has favorable effects on the coronary, pulmonary and peripheral circulations. Redistribution of the circulating blood offers an improved hemodynamic context for the development of a positive inotropic effect through Ca2+-sensitization of the contractile filaments, without a proportionate increase in myocardial oxygen consumption or the development of arrhythmias. Activation of ATP-sensitive K+ channels, both on sarcolemma and mitochondria, may protect against myocardial ischemia, and decreased levels of cytokines may prevent the development of further myocardial remodeling. Collectively, these effects of levosimendan shift the disturbed cardiovascular parameters towards normalization, thereby halting the perpetuation of the vicious cycle of heart failure progression. This may contribute to stabilization of the circulation and improved life expectancy of patients with chronic heart failure.

Effects of Levosimendan on Left Ventricular Diastolic Function After Primary Angioplasty for Acute Anterior Myocardial Infarction: A Doppler Echocardiographic Study

BACKGROUND

Levosimendan is a new Ca-sensitizing drug with combined positive inotropic and vasodilatory effects that offers new therapeutic possibilities in patients with severe heart failure. Compared with other inotropic agents, animal studies demonstrated that levosimendan does not impair left ventricular diastolic function.

OBJECTIVE

We sought to evaluate the effects of levosimendan on left ventricular diastolic function, using conventional transmitral Doppler and Doppler tissue imaging parameters, in patients with anterior acute myocardial infarction undergoing primary angioplasty.

METHODS

After a successful primary angioplasty, we randomized 52 consecutive patients with anterior acute myocardial infarction to levosimendan or placebo infusion and analyzed the diastolic function using conventional transmitral Doppler flow and Doppler tissue imaging at mitral annulus.

RESULTS

At 24 hours after the index intervention, patients treated with levosimendan (n = 26) showed a significant reduction of the isovolumetric relaxation time (114.6 +/- 15.1-69.2 +/- 5.6 milliseconds; P = .001) and the ratio between the early diastolic flow and early tissue velocity (E/E') (21.4 +/- 10.7-12.8 +/- 7.3; P = .04), and a significant increase of the ratio between the early and late diastolic flow (E/A) (0.86 +/- 0.33-1.52 +/- 0.88; P = .03) and E' (6.4-7.9 cm/s; P = .001). On the other hand, only a significant increase in E/A ratio (0.97 +/- 0.32-1.64 +/- 0.51; P = .002) was observed in the placebo group (n = 26).

CONCLUSIONS

Levosimendan, after primary angioplasty in patients with anterior acute myocardial infarction, appears to improve the Doppler echocardiographic parameters of left ventricular diastolic function.

Levosimendan for the treatment of acute heart failure syndromes

Levosimendan is a novel calcium-sensitising agent that has been shown to have beneficial inotropic, metabolic and vasodilatory effects in the treatment of acute and advanced chronic heart failure. Levosimendan binds to troponin-C in cardiomyocytes and, thereby, improves cardiac contractility without disturbing the metabolic status of the heart and increasing myocardial oxygen demand or provoking fatal cardiac arrhythmias. Levosimendan also opens ATP-sensitive potassium channels, causing peripheral arterial and venous dilatation, and increasing coronary flow reserve. When it is given as a short-term therapy, levosimendan enhances cardiac output, reduces systemic vascular resistance and lowers pulmonary capillary wedge pressure. Clinical outcomes were significantly reduced in decompensated or postmyocardial infarction heart failure patients who received levosimendan, compared with those on dobutamine or placebo. Recent investigations focusing on the anti-inflammatory and antiapoptotic actions of levosimendan in the failing heart indicate that improvement of cardiac contractile performance is closely related with the drug-induced reduction of circulating pro-inflammatory cytokines and apoptosis inducers. The most common adverse effects of levosimendan treatment are hypotension and headache. Overall, levosimendan represents an effective and safe option for the treatment of decompensated heart failure patients.

Levosimendan: a novel inotropic agent for treatment of acute, decompensated heart failure

OBJECTIVE

To review the literature on a novel calcium sensitizer, levosimendan.

DATA SOURCES

Articles were identified through searches of MEDLINE (1966-June 2005), International Pharmaceutical Abstracts (1970-June 2005), and EMBASE (1992-June 2005) using the key words levosimendan, simendan, calcium sensitizer, calcium sensitiser, and congestive heart failure.

STUDY SELECTION AND DATA EXTRACTION

Clinical trials and pharmacokinetic studies evaluating the safety and efficacy of levosimendan were selected.

DATA SYNTHESIS

Levosimendan 6-24 mug/kg intravenous bolus followed by a 24-hour continuous infusion of 0.05-0.2 microg/kg/min improved cardiac output and reduced pulmonary capillary wedge pressure in a dose-dependent manner. Dose-ranging and randomized clinical trials have demonstrated improvement in symptoms and hemodynamics and short-term survival outcomes in the treatment of acute, decompensated heart failure. Clinical trials evaluating retrospective mortality data and combined endpoints (mortality, rehospitalization) have demonstrated better outcomes with levosimendan compared with dobutamine. The incidence of hypotension with levosimendan is not significantly different than with dobutamine, but there is a dose-related increase in heart rate.

CONCLUSIONS

Levosimendan is useful in moderate to severe low-output heart failure in patients who have failed to respond to diuretics and vasodilators. Based on current studies, levosimendan appears to be a safe alternative to dobutamine for treatment of acute, decompensated heart failure. Prospective clinical trials are needed to confirm the effect of levosimendan on long-term survival and its role in heart failure in the setting of myocardial infarction.

Effects of Levosimendan on Restrictive Left Ventricular Filling in Severe Heart Failure

BACKGROUND

A restrictive pattern of left ventricular filling is often present in patients with severe heart failure. Although the hemodynamic effects of levosimendan have been studied, the effects of levosimendan on LV filling pattern have not been investigated.

METHODS

Pulsed-wave Doppler mitral (transthoracic) and pulmonary venous flow (transesophageal) velocity curves were recorded in 30 patients with a restrictive pattern of left ventricular filling with New York Heart Association class III or IV heart failure who had a documented left ventricular ejection fraction < 30% by echocardiography and received a 0.1 microg/kg/min infusion of levosimendan for 24 h.

RESULTS

Levosimendan caused significant (p < 0.001) increases in stroke volume (from 46 +/- 4 to 57 +/- 4 mL) and decreases in pulmonary capillary wedge pressure (from 21 +/- 1 to 15 +/- 1 mm Hg). The E wave decreased (from 96 +/- 7 to 71 +/- 5 cm/s), and the A wave increased (from 40 +/- 4 to 46 +/- 4 cm/s). Moreover, deceleration time was increased (from 112 +/- 7 to 189 +/- 14 ms). The S wave of pulmonary venous flow was increased (from 38 +/- 3 to 60 +/- 3 cm/s), and atrial reversal was decreased (from 36 +/- 2 to 29 +/- 2 cm/s). All changes were significant (p < 0.001). Using stepwise linear regression analysis, we found that the percentage changes of the early/late transmitral diastolic peak flow velocity (E/A) ratio and the percentage changes of the isovolumetric relaxation time were independent predictors of the increase in cardiac output. Furthermore, the percentage changes of the systolic/diastolic ratio and the percentage changes of the E/A ratio were independent predictors of the decrease in pulmonary capillary wedge pressure.

CONCLUSIONS

Treatment with levosimendan improved measures of left ventricular diastolic function. Consequently, left ventricular stroke volume was increased.

Pharmacology of new agents for acute heart failure syndromes

Current therapies for acute heart failure syndromes (AHFS) target hemodynamics by decreasing congestion or increasing myocardial contraction. Several new agents for AHFS use novel mechanisms of action that focus on new treatment targets, such as those providing anti-ischemic and anti-stunning effects, blocking vasopressin receptors, or blocking endothelin-1 receptors. For example, levosimendan acts as a calcium sensitizer and adenosine triphosphate-dependent potassium (K(ATP)) channel opener that increases contraction, causes vasodilation, and provides cardioprotective effects. This is accomplished by its dual mechanism of action. Levosimendan binds to cardiac troponin C, thereby enhancing calcium myofilament responsiveness and increasing myocardial contraction without increasing intracellular calcium levels. Thus, contraction is increased with no significant increase in myocardial oxygen consumption. The opening of K(ATP) channels by levosimendan causes vasodilation and exerts anti-ischemic and anti-stunning effects on the myocardium. Other new agents target neurohormonal pathways. Tezosentan is an antagonist of endothelin-1 receptors A and B. By inhibiting endothelin-1 receptors, tezosentan may counteract the activities of endothelin-1, which include vasoconstriction, proarrhythmic activities, potentiation of other neurohormones, and mediation of increased vascular permeability. Tolvaptan is a vasopressin V2-receptor antagonist that functions as an aquaretic (ie, it increases urine volume and serum sodium with little or no sodium loss). Therefore, by using novel mechanisms of action, these agents may provide new opportunities for helping patients with AHFS.

Effects of levosimendan on markers of left ventricular diastolic function and neurohormonal activation in patients with advanced heart failure

In this randomized, placebo-controlled study, it was found that a 24-hour levosimendan infusion improves echocardiographic markers of abnormal left ventricular diastolic function (transmitral flow patterns and mitral annulus velocities, as assessed by transthoracic pulse-wave Doppler and tissue Doppler imaging, respectively) and reduces substances of excessive neurohormonal activation (plasma B-type natriuretic peptide and interleukin-6) in patients with advanced heart failure. Moreover, levosimendan-treated patients had fewer events and longer progression-free survival during a 5-month follow-up compared with those who received placebo. Thus, levosimendan seems to be effective in improving left ventricular diastolic function and reducing neurohormonal activation in patients with severe heart failure.

An emerging role for calcium sensitisation in the treatment of heart failure

Heart failure occurs in 2 - 3% of the adult population in the developed world. With decompensation of cardiac function, haemodynamic stability can be achieved by using intravenous vasodilators, diuretics and inotropes. Unlike traditional inotropes, Ca2+ sensitisers enhance cardiac function without significantly increasing cardiac oxygen consumption, promoting arrhythmia or impairing lusitropy. The most promising drug in this new class is levosimendan, which has a unique dual mechanism; it enhances cardiac output through a Ca(2+)-dependent stabilisation of cardiac myofilaments and exhibits vasodilatory effects by opening ATP-dependent K(+) channels. Clinical trials have demonstrated the beneficial haemodynamic effects of levosimendan, and prospective trials are currently underway to confirm its potential benefits on long-term prognosis. Updated guidelines from the European Society of Cardiology advise on how to incorporate levosimendan into care for patients who have acute heart failure.

Force-frequency relationship in intact mammalian ventricular myocardium: physiological and pathophysiological relevance

The force-frequency relationship (FFR) is an important intrinsic regulatory mechanism of cardiac contractility. The FFR in most mammalian ventricular myocardium is positive; that is, an increase in contractile force in association with an increase in the amplitude of Ca(2+) transients is induced by elevation of the stimulation frequency, which reflects the cardiac contractile reserve. The relationship is different depending on the range of frequency and species of animal. In some species, including rat and mouse, a 'primary-phase' negative FFR is induced over the low-frequency range up to approximately 0.5-1 Hz (rat) and 1-2 Hz (mouse). Even in these species, the FFR over the frequency range close to the physiological heart rate is positive and qualitatively similar to that in larger mammalian species, although the positive FFR is less prominent. The integrated dynamic balance of the intracellular Ca(2+) concentration ([Ca(2+)](i)) is the primary cellular mechanism responsible for the FFR and is determined by sarcoplasmic reticulum (SR) Ca(2+) load and Ca(2+) flux through the sarcolemma via L-type Ca(2+) channels and the Na(+)-Ca(2+) exchanger. Intracellular Na(+) concentration is also an important factor in [Ca(2+)](i) regulation. In isolated rabbit papillary muscle, over a lower frequency range (<0.5 Hz), an increase in duration rather than amplitude of Ca(2+) transients appears to be responsible for the increase in contractile force, while over an intermediate frequency range (0.5-2.0 Hz), the amplitude of Ca(2+) transients correlates well with the increase in contractile force. Over a higher frequency range (>2.5 Hz), the contractile force is dissociated from the amplitude of Ca(2+) transients probably due to complex cellular mechanisms, including oxygen limitation in the central fibers of isolated muscle preparations, while the amplitude of Ca(2+) transients increases further with increasing frequency ('secondary-phase' negative FFR). Calmodulin (CaM) may contribute to a positive FFR and the frequency-dependent acceleration of relaxation, although the role of calmodulin has not yet been established unequivocally. In failing ventricular myocardium, the positive FFR disappears or is inverted and becomes negative. The activation and overexpression of cardiac sarcoplasmic reticulum Ca(2+) ATPase (SERCA2a) is able to reverse these abnormalities. Frequency-dependent alterations of systolic and diastolic force in association with those of Ca(2+) transients and diastolic [Ca(2+)](i) levels are excellent indicators for analysis of cardiac excitation-contraction coupling, and for evaluating the severity of cardiac contractile dysfunction, cardiac reserve capacity and the effectiveness of therapeutic agents in congestive heart failure.

Levosimendan improves LV systolic and diastolic performance at rest and during exercise after heart failure

The new myofilament Ca2+ sensitizer levosimendan (LSM) is a positive inotropic and vasodilatory agent. Its beneficial effects have been demonstrated at rest in congestive heart failure (CHF). However, its effect during exercise (Ex) in CHF is unknown. We assessed the effects of LSM on left ventricular (LV) dynamics at rest and during Ex in eight conscious, instrumented dogs with pacing-induced CHF. After CHF, with dogs at rest, LSM decreased arterial elastance ( Ea) and increased LV contractile performance as assessed by the slope of LV pressure-volume (P-V) relation. LSM caused a >60% increase in the peak rate of mitral flow (dV/d tmax) due to decreases in minimal LV pressure and the time constant of LV relaxation (τ). LV arterial coupling, quantified as the ratio of end-systolic elastance ( Ees) to Ea, was increased from 0.47 to 0.85%. LV mechanical efficiency, determined as the ratio of stroke work to total P-V area, was improved from 0.54 ± 0.09 to 0.61 ± 0.07. These beneficial effects persisted during Ex after CHF. Compared with CHF Ex dogs, treatment with LSM prevented Ex-induced abnormal increases in mean left atrial pressure and end-diastolic pressure and decreased Ees/ Ea. With LSM treatment during CHF Ex, the early diastolic portion of the LV P-V loop was shifted downward with decreased minimal LV pressure and τ values and a further augmented dV/d tmax. Ees/ Ea improved, and mechanical efficiency further increased from 0.61 ± 0.07 to 0.67 ± 0.07, which was close to the value reached during normal Ex. After CHF, LSM produced arterial vasodilatation; improved LV relaxation and diastolic filling; increased contractility, LV arterial coupling, and mechanical efficiency; and normalized the response to Ex.

The calcium sensitizer levosimendan improves the function of stunned myocardium after percutaneous transluminal coronary angioplasty in acute myocardial ischemia

OBJECTIVES

We assessed the effects of levosimendan on left ventricular (LV) function in patients with acute myocardial ischemia and after coronary angioplasty.

BACKGROUND

The calcium sensitizer levosimendan improves the function of myocardium in experimental stunning.

METHODS

Twenty-four patients with an acute coronary syndrome underwent angioplasty followed by double-blinded, randomized treatment with 24 microg/kg of levosimendan (n = 16) or placebo (n = 8). Left ventricular pressures and volumes were recorded by cineventriculography and micromanometer-tipped catheters 10 min after angioplasty before drug administration (baseline) and 20 min after drug administration. Left ventricular function was assessed by the pressure-volume loop, and regional function analysis by the Slager method.

RESULTS

The number of hypokinetic segments decreased with levosimendan, from 8.9 +/- 0.9 to 6.5 +/- 1.1 (mean +/- SEM), as compared with an increase from 7.8 +/- 1.0 to 8.5 +/- 1.1 with placebo (p = 0.016). A leftward and/or upward shift of the systolic part of the pressure-volume loop, indicating improved systolic function, was observed in eight of 16 of the levosimendan-treated and one of eight of the placebo patients (p = 0.178). In addition, the single-beat elastance was increased by levosimendan (p = 0.045). The pressure-volume area (p = 0.001), end-systolic pressure (p = 0.002), and volume index (p < 0.001) were decreased by levosimendan, but there was no change in the end-systolic pressure-volume ratio. End-diastolic pressure remained unchanged, whereas the end-diastolic volume index was decreased by levosimendan (p = 0.002). The time constant of isovolumic LV pressure fall decreased with levosimendan (p = 0.001).

CONCLUSIONS

Levosimendan improved the function of stunned myocardium without obvious impairment of diastolic function.

Levosimendan: a review of its use in the management of acute decompensated heart failure

Levosimendan (Simdax) is a calcium-sensitising drug that stabilises the troponin molecule in cardiac muscle, thus prolonging its effects on contractile proteins, with concomitant vasodilating properties. Intravenous levosimendan (12-24 microg/kg loading dose followed by 0.1-0.2 microg/kg/min for 24 hours, adjusted for response and tolerability) is approved for the short-term treatment of acute severe decompensated heart failure. Cardiac output increased by about 30% and pulmonary capillary wedge pressure and systemic vascular resistance decreased by about 17-29% in patients with decompensated heart failure receiving intravenous levosimendan. In large, well controlled trials in patients with decompensated heart failure, intravenous levosimendan was significantly more effective than placebo or dobutamine for overall haemodynamic response rate (primary endpoint). Significant benefits were also seen for mortality (versus placebo or dobutamine) and for the combined risk of worsening heart failure or death (versus dobutamine). Improvements in key symptoms (dyspnoea and fatigue) have not been consistently demonstrated. Hospitalisation costs were similar for levosimendan and dobutamine; the total incremental (hospitalisation plus drug) cost per life-year saved (extrapolated to 3 years) for levosimendan relative to dobutamine was estimated at Euro 3205 (year of costing 2000). Levosimendan is generally well tolerated, with an adverse event profile at recommended dosages similar to that in patients receiving placebo. Cardiac rate/rhythm disorders and headache were the most common events. At higher dosages, patients receiving levosimendan had higher rates of sinus tachycardia than those in placebo recipients. More patients receiving dobutamine than those receiving levosimendan experienced angina pectoris/chest pain/myocardial ischaemia or rate/rhythm disorders.

CONCLUSION

Intravenous levosimendan is an effective calcium-sensitising drug with vasodilatory and inotropic effects, and superior efficacy/tolerability to those of intravenous dobutamine in patients with acute decompensated heart failure. It may be associated with reduced mortality compared with both placebo and dobutamine. Levosimendan is generally well tolerated and may have less potential for cardiac rate/rhythm disorders than dobutamine. While evidence from well designed trials confirming the improved mortality over dobutamine and investigating haemodynamic efficacy and mortality versus other positive inotropes is required, intravenous levosimendan appears to be a useful addition to the treatment options for acute decompensated heart failure in patients with low cardiac output.

Selective contractile dysfunction of left, not right, ventricular myocardium in the SHHF rat

The progression of hypertension to cardiac failure involves systemic changes that may ultimately affect contractility throughout the heart. Spontaneous hypertensive heart failure (SHHF) rats have depressed left ventricular (LV) function, but right ventricular (RV) dysfunction is less well characterized. Ultrathin (87 +/- 5 mircom) trabeculae were isolated from end-stage failing SHHF rats and from age-matched controls. Under near-physiological conditions (1 mM Ca(2+), 37 degrees C, 4 Hz), developed force (in mN/mm(2)) was not significantly different in SHHF LV and RV trabeculae and those of controls. SHHF LV preparations displayed a negative force-frequency behavior (40 +/- 7 vs. 23 +/- 4 mN/mm(2), 2 vs. 7 Hz); this relationship was positive in SHHF RV preparations (27 +/- 5 vs. 40 +/- 6 mN/mm(2)) and controls (32 +/- 6 vs. 44 +/- 9 mN/mm(2)). The response to isoproterenol (10(-6) M, 4 Hz) was depressed in SHHF LV preparations. The inotropic response to hypothermia was lost in SHHF LV trabeculae but preserved in SHHF RV trabeculae. Intracellular calcium measurements revealed impaired calcium handling at higher frequencies in LV preparations. We conclude that in end-stage failing SHHF rats, RV function is only marginally affected, whereas a severe contractile dysfunction of LV myocardium is present.