Overview of the relationship between ischemia and congestive heart failure

Ischemic heart disease is the principal etiology of heart failure in the Western world. Myocardial ischemia is important in cardiac remodeling, a process that leads to a progressive change in the shape and size of the heart and significantly worsens the prognosis of patients with heart failure. Preventing ischemic events, therefore, is an important goal in the management of patients with coronary artery disease. Statins have been shown to reduce the number of ischemic events in these patients, whereas the benefit of beta-blocker and aldosterone antagonist therapy on ischemic causes of heart failure remains unclear. Several large trials involving patients with asymptomatic left ventricular dysfunction after myocardial infarction or heart failure have shown that angiotensin-converting enzyme (ACE) inhibitors reduce the incidence of progressive heart failure, death, and ischemic events, thus establishing ACE inhibitors as first-line therapy for these patients. Other lines of evidence have suggested that ACE inhibitor therapy may also benefit patients with preserved left ventricular function, a hypothesis that is being evaluated in three large, controlled, randomized trials. One of these trials, the Heart Outcomes Prevention Evaluation (HOPE) study, was terminated prematurely because it demonstrated the significant positive effects of the ACE inhibitor ramipril on cardiovascular outcomes in patients with coronary artery disease and preserved left ventricular function. A growing body of data confirms the relationship between ischemia and heart failure and the benefits of ACE inhibitor treatment in a broad range of high-risk patients.

ACE inhibition and endothelial function: main findings of PERFECT, a sub-study of the EUROPA trial

Background

ACE inhibition results in secondary prevention of coronary artery disease (CAD) through different mechanisms including improvement of endothelial dysfunction. The Perindopril-Function of the Endothelium in Coronary artery disease Trial (PERFECT) evaluated whether long-term administration of perindopril improves endothelial dysfunction.

Methods

PERFECT is a 3-year double blind randomised placebo controlled trial to determine the effect of perindopril 8 mg once daily on brachial artery endothelial function in patients with stable CAD without clinical heart failure. Endothelial function in response to ischaemia was assessed using ultrasound. Primary endpoint was difference in flow-mediated vasodilatation (FMD) assessed at 36 months.

Results

In 20 centers, 333 patients randomly received perindopril or matching placebo. Ischemia-induced FMD was 2.7% (SD 2.6). In the perindopril group FMD went from 2.6% at baseline to 3.3% at 36 months and in the placebo group from 2.8 to 3.0%. Change in FMD after 36 month treatment was 0.55% (95% confidence interval −0.36, 1.47; p = 0.23) higher in perindopril than in placebo group. The rate of change in FMD per 6 months was 0.14% (SE 0.05, p = 0.02) in perindopril and 0.02% (SE 0.05, p = 0.74) in placebo group (0.12% difference in rate of change p = 0.07).

Conclusion

Perindopril resulted in a modest, albeit not statistically significant, improvement in FMD.

The Carvedilol and ACE-Inhibitor Remodelling Mild Heart Failure EvaluatioN trial (CARMEN)--rationale and design

Inhibition or reversal of ventricular remodelling in heart failure patients is regarded as of prime importance in the treatment of heart failure and in determining long term outcome. Recent studies have demonstrated that the addition of carvedilol to Angiotensin Converting Enzyme (ACE) inhibitors and other routine heart failure therapy results in a valuable improvement in the clinical status and life expectancy of mild, moderate and severe heart failure patients. ACE inhibitors have become the cornerstone of heart failure therapy. Also, carvedilol in combination with standard therapy (including ACE inhibitors) has demonstrable beneficial effects on left ventricular remodelling. Each new treatment has to be added, this quickly leads to polypharmacy, which may not be necessary and even unwanted in the individual patient, as the pharmacological profile of carvedilol compares favourably to ACE inhibitors, this suggests that it could challenge ACE inhibitors as first-line treatment for heart failure. The CARMEN trial (Carvedilol and ACE-Inhibitor Remodelling Mild Heart Failure EvaluatioN) was designed to compare the effects of carvedilol alone and of carvedilol plus an ACE inhibitor (enalapril) with the effect of an ACE inhibitor alone on different parameters of left ventricular remodelling as well as morbidity and mortality in patients with chronic mild heart failure, thereby allowing conclusions on whether combination therapy may be replaced by the multiple action adrenergic inhibitor carvedilol in the future.

Hemodynamic and neurohumoral effects of continuous infusion of levosimendan in patients with congestive heart failure

OBJECTIVES

We sought to define the therapeutic dose range of levosimendan in patients with New York Heart Association class II-IV heart failure of ischemic origin.

BACKGROUND

Levosimendan is a calcium sensitizer for treatment of acute decompensated heart failure.

METHODS

A double-blind, placebo-controlled, randomized, multicenter, parallel-group study included 151 adult patients. Levosimendan was given as a 10-min intravenous bolus of 3, 6, 12, 24 or 36 microg/kg, followed by a 24-h infusion of 0.05, 0.1, 0.2, 0.4 or 0.6 microg/kg/min, respectively. Dobutamine, for comparative purposes, was given as an open-label infusion (6 microg/kg/min). The primary efficacy variable was the proportion of patients achieving in each treatment group at least one of the following: 1) a > or =15% increase in stroke volume (SV) at 23 h to 24 h; 2) a > or =25% decrease in pulmonary capillary wedge pressure (PCWP) (and > or =4 mm Hg) at 23 h to 24 h; 3) a > or =40% increase in cardiac output (CO) (with change in heart rate [HR] <20%); 4) a > or =50% decrease in PCWP during two consecutive measurements.

RESULTS

The response rate to levosimendan ranged from 50% at the lowest dose to 88% at the highest dose (compared with placebo 14%, dobutamine 70%). A dose-response relationship was demonstrated for levosimendan on increases in CO and SV, and reductions in PCWP during the infusion (for all, p< or =0.001). Headache (9%), nausea (5%) and hypotension (5%) were the most frequently reported adverse events at higher dosages.

CONCLUSIONS

Dosing of levosimendan with a 10-min bolus of 6 to 24 microg/kg followed by an infusion of 0.05 to 0.2 microg/kg/min is well tolerated and leads to favorable hemodynamic effects.

Differential anti-ischaemic effects of muscarinic receptor blockade in patients with obstructive coronary artery disease; impaired vs normal left ventricular function

AIMS

In patients with coronary artery disease acetylcholine (a muscarinic agonist) causes vasoconstriction. The effect of atropine (a muscarinic antagonist) on coronary vasotone in patients with normal or impaired left ventricular function is unknown.

METHODS AND RESULTS

Twenty-four patients who required atropine infusion (to supplement heart rate response) during atrial pacing (pacing was conducted to assess ischaemia as part of an experimental protocol) were studied; 17 patients had normal and seven impaired left ventricular function (ejection fraction < or =0.40). Two control groups were selected from a large database (from patients in whom atrial pacing was carried out but to whom atropine was not administered) to match the normal (n=20) and dysfunction (n=10) groups. In the normal left ventricular function group atropine increased rate pressure product by 12 +/- 4%, as compared to those without atropine (P < 0.05). Left ventricular end diastolic pressure increased less in the atropine group (+40 +/- 8% vs +78 +/- 6%;P < 0.05). Arterial norepinephrine increased similarly in both groups, but coronary flow (as assessed by using a thermodiluting method in the coronary sinus) increased 23 +/ -4% more in the atropine group (P < 0.05). Further, there were lower levels of myocardial lactate production and ST-segment depression in the atropine group [lactate extraction +13 +/- 6% (atropine) vs -19 +/- 4% (controls), ST-segment depression 1. 3 +/- 0.6 (atropine) vs 1.8 +/- 0.2 mm (control), both P < 0.05 between groups]. In contrast, in the dysfunction group the overall effect of atropine was less pronounced.

CONCLUSION

In patients with normal left ventricular function atropine improves coronary flow and reduces myocardial lactate production and ST-segment depression during atrial pacing, suggesting a reduction in myocardial ischaemia.

The effect of spironolactone on morbidity and mortality in patients with severe heart failure. Randomized Aldactone Evaluation Study Investigators

BACKGROUND AND METHODS

Aldosterone is important in the pathophysiology of heart failure. In a doubleblind study, we enrolled 1663 patients who had severe heart failure and a left ventricular ejection fraction of no more than 35 percent and who were being treated with an angiotensin-converting-enzyme inhibitor, a loop diuretic, and in most cases digoxin. A total of 822 patients were randomly assigned to receive 25 mg of spironolactone daily, and 841 to receive placebo. The primary end point was death from all causes.

RESULTS

The trial was discontinued early, after a mean follow-up period of 24 months, because an interim analysis determined that spironolactone was efficacious. There were 386 deaths in the placebo group (46 percent) and 284 in the spironolactone group (35 percent; relative risk of death, 0.70; 95 percent confidence interval, 0.60 to 0.82; P<0.001). This 30 percent reduction in the risk of death among patients in the spironolactone group was attributed to a lower risk of both death from progressive heart failure and sudden death from cardiac causes. The frequency of hospitalization for worsening heart failure was 35 percent lower in the spironolactone group than in the placebo group (relative risk of hospitalization, 0.65; 95 percent confidence interval, 0.54 to 0.77; P<0.001). In addition, patients who received spironolactone had a significant improvement in the symptoms of heart failure, as assessed on the basis of the New York Heart Association functional class (P<0.001). Gynecomastia or breast pain was reported in 10 percent of men who were treated with spironolactone, as compared with 1 percent of men in the placebo group (P<0.001). The incidence of serious hyperkalemia was minimal in both groups of patients.

CONCLUSIONS

Blockade of aldosterone receptors by spironolactone, in addition to standard therapy, substantially reduces the risk of both morbidity and death among patients with severe heart failure.

Sustained benefit at 10-14 years follow-up after thrombolytic therapy in myocardial infarction

AIMS

To investigate whether the benefit of thrombolytic therapy was sustained beyond the first decade. We report the 10-14 year outcome of 533 patients who were randomized to treatment with intracoronary streptokinase or to conventional therapy during the years 1980-1985.

METHODS AND RESULTS

Details of survival and cardiac events were obtained from the civil registry, from medical records or from the patient's physician. At follow-up, 158 patients (59%) of the 269 patients allocated to thrombolytic treatment and only 129 patients (49%) of the 264 conventionally treated patients were alive. The cumulative 1-, 5- and 10-year survival rates were 91%, 81% and 69% in patients treated with streptokinase and 84%, 71% and 59% in the control group, respectively (P=0.02). Reinfarction during 10-years of follow-up was more frequent after thrombolytic therapy, particularly during the first year. Coronary bypass surgery and coronary angioplasty were more frequently performed after thrombolytic therapy. At 10 years approximately 30% of the patients were free from subsequent cardiac events. Independent determinants of mortality were elderly age, indicators of impaired residual left ventricular function, multivessel disease and an inability to perform an exercise test at the time of hospital discharge.

CONCLUSION

Improved survival after thrombolytic therapy is maintained beyond the first decade. Age, left ventricular function, multivessel disease and an inability to perform an exercise test were independent predictors for long-term mortality, as they are predictors for early mortality.

Drug-induced heart failure

Heart failure is a clinical syndrome that is predominantly caused by cardiovascular disorders such as coronary heart disease and hypertension. However, several classes of drugs may induce heart failure in patients without concurrent cardiovascular disease or may precipitate the occurrence of heart failure in patients with preexisting left ventricular impairment. We reviewed the literature on drug-induced heart failure, using the MEDLINE database and lateral references. Successively, we discuss the potential role in the occurrence of heart failure of cytostatics, immunomodulating drugs, antidepressants, calcium channel blocking agents, nonsteroidal anti-inflammatory drugs, antiarrhythmics, beta-adrenoceptor blocking agents, anesthetics and some miscellaneous agents. Drug-induced heart failure may play a role in only a minority of the patients presenting with heart failure. Nevertheless, drug-induced heart failure should be regarded as a potentially preventable cause of heart failure, although sometimes other priorities do not offer therapeutic alternatives (e.g., anthracycline-induced cardiomyopathy). The awareness of clinicians of potential adverse effects on cardiac performance by several classes of drugs, particularly in patients with preexisting ventricular dysfunction, may contribute to timely diagnosis and prevention of drug-induced heart failure.

Acute anti-ischemic effects of perindoprilat in men with coronary artery disease and their relation with left ventricular function

Long-term angiotensin-converting enzyme (ACE) inhibition may reduce ischemic events in patients with coronary artery disease, but whether it protects against acute ischemia or the effects of preexisting left ventricular (LV) dysfunction on potential anti-ischemic properties is unknown. We performed a double-blind trial in 25 patients with exercise-induced ischemia. The effects of perindoprilat on pacing-induced myocardial ischemia were examined. Fourteen patients received perindoprilat and 11 patients received placebo. Based on LV function, 2 subgroups were formed in the perindoprilat group: 7 patients with LV dysfunction (LV ejection fraction <0.40), and 7 patients with normal LV function. After receiving the study medication, the pacing test was repeated. During the first pacing test both groups developed ischemia. After perindoprilat administration, the increase in systemic vascular resistance and LV end-diastolic pressure were significantly blunted (p <0.05). Further, the ischemia-induced increase in arterial and cardiac uptake of norepinephrine was inhibited by perindoprilat, and the increase in atrial natriuretic peptide was less pronounced; also, ST-segment depression was reduced by 32% compared with placebo (all p <0.05). In the group with LV dysfunction, perindoprilat reduced LV end-diastolic pressure significantly by 67% and myocardial lactate production was prevented, but this did not happen in the group with normal LV function. In addition, the increase in arterial norepinephrine was reduced by 74% and 33%, respectively (p <0.05). These results indicate that perindoprilat reduced acute, pacing-induced ischemia in normotensive patients. In patients with (asymptomatic) LV dysfunction these effects were more pronounced than in patients with normal LV function.

Towards the better treatment of heart failure

During recent decades, heart failure has become one of, if not the, most important syndrome(s) in the cardiovascular area in terms of prevalence, morbidity, healthcare costs and mortality. Although heart failure treatment has developed rapidly and several novel approaches aimed at preventing or retarding worsening of failure are available in addition to those providing symptomatic relief, many patients are still treated inappropriately. This is particularly true for angiotensin-converting enzyme (ACE) inhibition, which, despite the fact that only slightly more than 50% of heart failure patients receive this form of therapy, should be given to all patients with the syndrome, irrespective of the severity. Heart failure patients are under the care of different types of doctors, including general practitioners (estimated 80-85%) and internists and geriatricians (10-15%); cardiologists see relatively few patients. Pertinent studies in heart failure have, however, been performed by the latter group and, in general, awareness of the clinical usefulness and prescription of ACE inhibitors is therefore highest amongst these specialists. As the management of heart failure is transmural in nature, proper education of the different echelons is mandatory. Guidelines on the diagnosis and treatment of heart failure are pivotal in this process. However, it is not an easy task to prepare guidelines that are applicable in all circumstances and can be used by any kind of doctor involved in heart failure care. It is even more difficult to ensure the guidelines are implemented and it requires the input of both individual doctors and the national and international medical associations. The European Society of Cardiology is dedicated to this educational process and, through its Educational and Training Programme Committee and relevant Working Groups such as the Working Group on Heart Failure, has already set programmes into motion.

Effect of ACE inhibition on neurohormones

Long-term controlled trials in heart failure in patients with asymptomatic left ventricular dysfunction indicate the potential of ACE inhibition to reduce ischaemic events, such as unstable angina and myocardial infarction. These effects occur after long-term medication and suggest structural rather than functional effects of ACE inhibitors. Such structural effects could include an improvement in endothelial function and less atherosclerosis of coronary and systemic arteries, as well as a reduction in cardiac size. Together, these effects may improve the myocardial oxygen supply/demand ratio. Neurohormonal activation is pivotal in heart failure and also occurs in patients with asymptomatic left ventricular dysfunction. ACE inhibitors modulate neurohormonal activation and, through that mechanism, may induce their beneficial effects in terms of cardiac remodelling and improved morbidity and mortality in heart failure patients. Neurohormonal activation also occurs during acute myocardial infarction, particularly in patients with diminished left ventricular dysfunction or heart failure. Recent studies indicate that short episodes of stress-induced myocardial ischaemia may also lead to significant increases in circulating norepinephrine, epinephrine and, in more severe ischaemia, in angiotensin II. This increase in vasoconstricting neurohormones results in significant systemic vasoconstriction and may also underlie the constriction of abnormal coronary segments observed during atrial pacing-induced stress. This ischaemia-induced neurohormonal activation is not dependent on the stress of angina, but correlates with the degree of myocardial ischaemia and also with the presence of left ventricular dysfunction. Acute ACE inhibition modulates this ischaemia-induced neurohormonal activation and the subsequent effects on systemic and coronary vascular tone. Consequently, acute ACE inhibition significantly reduces acute myocardial ischaemia. The significance of these observations is as yet unclear. However, they may be important in situations of severe myocardial ischaemia, such as unstable angina and acute myocardial infarction. Presumably, this potential of ACE inhibitors to reduce short-term stress-induced myocardial ischaemia as a result of their neurohormonal modulating and subsequent vasodilating effects gains in significance during chronic ACE inhibitor treatment, in parallel with a long-term improvement of coronary endothelial function.

Renal hemodynamic effects in patients with moderate to severe heart failure during chronic treatment with trandolapril

Treatment of patients with severe heart failure by ACE inhibition is often limited by worsening of renal function. To evaluate whether trandolapril, a potent lipophilic ACE inhibitor, affects renal function in severe heart failure, we studied 12 patients with severe heart failure treated with only diuretics and digoxin. Patients received increasing oral dosages of trandolapril (0, 1, and 2 mg) on 3 consecutive days (A). Patients were then discharged on 2 mg trandolapril bid and re-evaluated 8 weeks later (B). Mean arterial and pulmonary wedge pressures decreased by maximal 14% and 43%, and stroke volume and work indexes increased by 24% and 20% at A and similarly at B (11, 45, and 25 ns and 33%, respectively). In contrast, heart rate, systemic resistance, pulmonary artery pressure, and cardiac index decreased by 6%, 23%, 29%, and 17%, respectively, at only A. Renal blood flow improved by approximately 40% both at A and B. In contrast, the glomerular filtration rate decreased by 25% at only B, whereas serum creatinine, creatinine clearance, and urine osmolality were unaffected during the study. Norepinephrine, angiotensin II, and aldosterone levels decreased by approximately 30%, 60%, and 65%, respectively, at both A and B. Renin levels increased by 136% at A and remained elevated at B. Thus, whereas the initial systemic vasodilating and inotropic effects did not persist, long-term trandolapril results in sustained neurohormonal modulation, reduced preload, and improved organ perfusion, indicated by a persistent increase in renal blood flow and preservation of renal function in severe heart failure.

EUROPA substudies, confirmation of pathophysiological concepts. European trial on reduction of cardiac events with perindopril in stable coronary artery disease

In patients with coronary disease, ACE inhibitors may improve endothelial function in the coronary arteries as well as peripheral arteries, and may have anti-proliferative effects which might result in retardation of progression of coronary artery disease. In order to verify these pathophysiological concepts, a series of substudies will be conducted as part of the EUROPA programme. Angiographic and intravascular ultrasound examination of coronary arteries will be performed in approximately 400 patients before and after 3 years' treatment with either perindopril or placebo, in order to assess progression and possible regression of coronary lesions. B-mode ultrasonography of the brachial artery will be used as a model for changes in the coronary arteries, to assess endothelial function in response to ischaemia (reactive hyperaemia) and to vasoconstriction (cold pressor test). Three hundred patients will be investigated before and at different intervals after initiation of study treatment. In addition genetic characterization will be performed of patients participating in EUROPA in order to assess whether specific genotypes do respond more or less favourably to perindopril. In addition, the effect of perindopril will be investigated in patients with diabetes type II, since ACE inhibition in such patients may improve microvascular function and renal function. Integration of these substudies, as well as detailed analysis of other specific subgroups in EUROPA, will help us understand the effects of treatment with perindopril in patients with stable coronary artery disease.

The European trial on reduction of cardiac events with perindopril in stable coronary artery disease (EUROPA)

BACKGROUND

Angiotensin-converting enzyme (ACE) inhibitors have an accepted place in the treatment of hypertension and heart failure. However, at present they have no specific role in the prevention or treatment of coronary artery disease: evidence from animal experiments and some of the large ACE inhibitor cardiac studies makes this effect well worth testing.

OBJECTIVE

The objective of EUROPA is to assess the effects of perindopril (an ACE inhibitor) on outcome in patients with stable coronary artery disease, but no clinical heart failure.

METHODS

This is a double-blind, placebo-controlled, multicentre study with a duration of 3.5 years. It is proposed to recruit 10500 patients from 24 countries in Europe. The primary end-point is a combined one: total mortality, non-fatal acute myocardial infarction, unstable angina pectoris and cardiac arrest with successful resuscitation are included; the outcome is studied in patients with proven coronary artery disease and no clinical heart failure. Secondary end-points consist of these events individually calculated. The first patient was recruited in October 1997, and it is planned to finish recruitment by the end of 1998.

Neurohumoral response to carmoxirole, a selective dopamine (D2) receptor agonist, in patients with chronic moderate heart failure

Neurohormonal activation and elevated ventricular filling pressures are prominent features in heart failure. Carmoxirole is a DA2 receptor agonist with limited central activity that modulates sympathetic activation and subsequently reduces pre-load and afterload in animals. The effect of carmoxirole on neurohormones and hemodynamics in humans was evaluated in 12 normotensive patients with NYHA class III-IV heart failure on stable ACE 1 and diuretic therapy. Carmoxirole (0.25-1.00 mg) was administered on 2 consecutive days, and hemodynamic and neurohormonal measurements were carried out. Values given are maximal percent changes from prestudy baseline (significance level P < 0.05). The lower dose on day 1 (0.25-0.50 mg) reduced circulating norepinephrine, vasopressin, and ANP by 40%, 19%, and 25%, respectively. In addition, on day 2, at a dose level of 0.75-1.00 mg, plasma renin activity decreased by 30%. Mean arterial pressure and systemic vascular resistance were reduced by 10% and 18%, and pulmonary wedge and right atrial pressure by 38% and 39%, respectively. Cardiac index improved by 20%. Despite a concomitant 12% reduction in heart rate, both stroke volume and stroke work index increased by 32% and 31%, respectively. Mean pulmonary artery pressure decreased by 21%, whereas pulmonary resistance was not affected. Thus, carmoxirole modulates sympathetic activation, accompanied by changes in vasopressin and ANP, and the renin-angiotensin system at higher dosages. These effects lead to a reduction in systemic resistance and heart rate, and an improvement in cardiac pump function and left and right ventricular filling pressures. It is concluded that carmoxirole induces beneficial effects on hemodynamic and neurohumoral parameters in heart failure.

Treatment guidelines in heart failure

The risk of heart failure increases with age. Prognosis is poor, with 82% of patients dying within 6 years of diagnosis. As the population ages, heart failure is becoming an increasing problem. Heart failure is a complex disease that may be managed in a variety of ways depending on its severity and cause. A wide range of pharmacological and nonpharmacological therapeutic measures are available to relieve symptoms and prolong life. These have changed considerably in the last decade. Cardiology experts in the United States and Europe have developed guidelines for the diagnosis and management of heart failure. These are intended to help physicians to keep up with therapeutic developments and to encourage more appropriate and cost-effective management of patients with heart failure. The European guidelines were updated more recently than their US counterparts and consequently contain certain new developments, such as the inclusion of the latest data on beta-blockers, including carvedilol, that have shown morbidity and mortality rate benefits in patients with mild-to-moderate heart failure. As the management of heart failure is changing rapidly, regular schemes for updating of guidelines are being considered.

The sympathetic nervous system and ischaemic heart disease

The sympathetic nervous system, coronary artery disease and myocardial ischaemia are related in different ways. First, the sympathetic system may be involved in the process of atherosclerosis through platelet activation and subsequent platelet-derived growth factor formation and by inducing mechanical injury to the vascular wall as a result of increased blood pressure and increased flow velocity. Secondly, sympathetic control of coronary vasomotor tone, which under normal conditions is not important, becomes functionally significant once coronary artery disease endothelial dysfunction has occurred. Under these circumstances, increased sympathetic adrenergic tone may lead to coronary vasoconstriction and, as myocardial oxygen demand increases concomitantly, myocardial ischaemia may ensue. Alternatively, myocardial ischaemia activates several neurohormonal systems, such as the sympathetic and, during more severe ischaemia, the circulating renin-angiotensin system. This leads to systemic and, possibly, coronary vasoconstriction and thus to further myocardial ischaemia. Prolonged myocardial ischaemia results in progressive norepinephrine release from the heart, reaching extracellular levels as high as 100-1000 x plasma concentrations. As cardiac beta-receptor density rises simultaneously, sympathetically-induced irreversible myocardial damage may occur, although through concomitantly increased beta-receptor kinase activity the beta-receptor may become functionally inactive. To counteract the detrimental effects of enhanced sympathetic activation on the heart, beta-blockade appears to be the proper choice. However, acute beta-blockade may lead to more profound ischaemia-induced neurohormonal activation and hence to vascular constriction through unoccupied alpha-receptors. In contrast, under ischaemic conditions and with concomitant beta-blockade, acute alpha-blockade does improve subendocardial flow and reduces myocardial ischaemia. A novel approach to anti-ischaemic therapy, which relates to modulating ischaemia-induced sympathetic activation, is through ACE inhibition. ACE inhibitors affect myocardial ischaemia by reducing neurohormonal activation and related systemic and coronary vasoconstriction. These acute effects may become more important over time, as coronary endothelial function improves following long-term ACE inhibition. A large multicentre controlled trial comparing ACE inhibition with placebo in patients with coronary artery disease, the EUROPA (EUopean trial on Reduction Of cardiac events with Perindopril in stable coronary Artery disease), which is currently underway, addresses the issue of whether ACE inhibition does in fact offer a novel approach in myocardial ischaemia.

Effects of epanolol, a selective beta1-blocker with intrinsic sympathomimetic activity, in patients with ischemic left ventricular dysfunction

Recently, different beta-blockers have been shown to be effective in the treatment of chronic heart failure (CHF), but the importance of their ancillary properties is not clear. Epanolol is a selective beta1-blocker with intrinsic sympathomimetic activity, which has been shown useful in angina pectoris, but its value in patients with left ventricular (LV) dysfunction and CHF is unknown. We examined the effects of epanolol in patients with LV dysfunction (n = 8; mean LV ejection fraction, 0.33 +/- 0.08) and compared them with patients with normal LV function (n = 8; mean LV ejection fraction, 0.52 +/- 0.04). Measurement of invasive hemodynamics and neurohormones was performed at rest and during myocardial ischemia, which was induced by atrial pacing. All measurements were performed before and after epanolol. Before epanolol, pacing-induced ischemia led to a similar increase in norepinephrine and coronary sinus blood flow in both groups. After epanolol, the increase in neurohormones was more pronounced in the group with LV dysfunction (norepinephrine, 1,130 +/- 164 pg/ml for patients with LV dysfunction vs. 637 +/- 41 pg/ml for normal subjects; p < 0.05). A similar effect was observed for angiotensin II. Further, in the LV-dysfunction group, coronary sinus blood flow increased less, and coronary vascular resistance decreased less (both values, p < 0.05). Despite the fact that the increase in double product was decreased to a similar extent in both groups, ischemia was reduced only in normal LV function (p < 0.05). In ischemic LV dysfunction, neurohumoral activation after epanolol may impair adequate coronary flow response, and this may limit its antiischemic properties. Because of the small size of the study, no definitive inference on the clinical benefit of epanolol in patients with ischemic LV function can be made from this study.

Prevention of worsening heart failure: future focus

For decades heart failure therapy has focused on symptomatic treatment, whereas preventive aspects have received less attention. However, 10 years of large controlled trials has provided insight into the potential of certain agents to prevent or delay the onset or worsening of heart failure. Such agents include ACE inhibitors and, in addition to the former beta-blockade, the vasodilator beta-blocking agent carvedilol, which possesses additional properties such as antioxidant effects. In contrast, drugs which typically are used to improve heart failure symptoms, such as diuretics, do not necessarily lead to prevention of (worsening) heart failure. Multiple mechanisms underlie worsening of left ventricular dysfunction and heart failure and have been, or may well be, instrumental in the development of novel preventive therapies of this syndrome. Principal mechanisms include: cardiac and vascular remodelling; neurohormonal and cytokine activation; hibernation and stunning; ischaemia-induced free radical formation; apoptosis; abnormalities in the cardiac membrane receptor, downstream signalling pathways, in intracellular calcium homeostasis, and sensitivity. As these mechanisms interact, leading to progression of heart failure, they provide opportunities for novel pharmacotherapeutic approaches. It is to be expected that many drugs currently in development will be added to the list of accepted heart failure therapy. As polypharmacy is likely to result and is to some extent unavoidable, the future challenge will be to detect the usefulness of alternative treatments to currently accepted therapy to prevent worsening of heart failure, enabling a more individualized and hence effective approach in each patient.

Bradykinin-mediated cardiovascular protective actions of ACE inhibitors. A new dimension in anti-ischaemic therapy?

In addition to being accepted therapy in hypertension and heart failure, ACE inhibitors may well offer a new dimension in anti-ischaemic therapy. Currently, anti-ischaemic properties have been demonstrated by ACE inhibitors in selected patient groups, including patients with left ventricular dysfunction with or without a direct temporal relationship with myocardial infarction. Anti-ischaemic effects of ACE inhibitors become apparent late after initiation of treatment and suggest a structural rather than a functional effect. Underlying mechanisms may include a reduction in ventricular dilatation and (abnormal) cardiac hypertrophy, leading to less myocardial oxygen demand and, possibly, improved subendocardial blood supply, and vasculoprotective effects, i.e. anti-atherosclerotic and antiremodelling properties, a beneficial effect on the fibrinolytic system and an improvement in abnormal endothelial vasodilator function. The latter aspect is most probably the pivotal mode of action where the anti-ischaemic profile of ACE inhibition is concerned. An improvement in endothelial dysfunction has been shown in patients with mild to moderate coronary artery disease [Trial on Reversing ENdothelial Dysfunction (TREND)]. It is of importance that, in both clinical experiments and human studies, the role of bradykinin appears central in the structural and functional cardiovascular effects of ACE inhibition. This is particularly true for the improvement of impaired endothelial function. Myocardial ischaemia evokes vasoconstrictor neurohormonal activation, which may lead to coronary vasoconstriction in diseased coronary segments. The subsequent abnormal endothelial function leads to diminished coronary flow and also increases systemic vasotone and afterload, thus unfavourably altering the myocardial oxygen supply/demand ratio. Under laboratory conditions, acute ACE inhibition counteracts this activation in humans. However, it is speculated that this anti-ischaemic mechanism may become operative and clinically important during long term oral ACE inhibitor therapy when endothelial function improves, and may subsequently protect against the vasoconstrictor effect of neurohormonal activation. As it is unlikely that the mechanisms mentioned above are only relevant in patients with ventricular dysfunction or heart failure, several large controlled trials are currently examining the long term anti-ischaemic and cardiovascular protective effects of ACE inhibition in patients at risk of a cardiovascular event [Heart Outcomes Prevention Evaluation study (HOPE)], with a normal cardiac function [Prevention of Events with ACE inhibition study (PEACE)] or in all patients with coronary artery disease irrespective of cardiac function [EUropean trial of Reduction Of cardiac events with Perindopril in stable coronary Artery disease (EUROPA)].

A non-invasive selective assessment of type I fibre mitochondrial function using 31P NMR spectroscopy. Evidence for impaired oxidative phosphorylation rate in skeletal muscle in patients with chronic heart failure

BACKGROUND

Skeletal muscle abnormalities contribute considerably to the clinical expression of heart failure. Deconditioning, underperfusion and an increased number of type IIb glycolytical fibres lead to early lactate production and muscle fatigue at low exercise levels. Aerobic muscle metabolism may also be impaired, as suggested by biopsy studies. Thus far, no data are available from non-invasive studies to indicate the extent of aerobic muscle dysfunction during low-grade exercise which does not induce acidosis.

METHODS AND RESULTS

Mitochondrial function of skeletal muscle during fibre type I activation was studied in 22 patients with chronic heart failure [NYHA class III, left ventricular ejection fraction 28 +/- 2%, (patients)] on ACE inhibitors, diuretics and digoxin, and in 20 normal subjects, using 31P NMR spectroscopy of a single right forearm flexor muscle during three mild intermittent exercise levels (0-40% of maximum voluntary contraction) and recovery time. At rest, the inorganic phosphate/phosphocreatine ratio was different [0.13 +/- 0.005 (patients) vs 0.09 +/- 0.002 (normal subjects), P = 0.0001]. However, intracellular pH was comparable. Local acidosis (tissue pH < 6.9) was avoided to prevent fibre type IIb activation. Calculated resting phosphate potential levels were comparable, but the slope and intercept of the linear relationship of phosphate potential and workload were significantly lower in patients than in normal subjects (11.7 +/- 0.7 vs 15.8 +/- 0.6 and 139 +/- 7 vs 196 +/- 7, patients vs normal subjects, indicating early exhaustion of intracellular energy at lower exercise levels. Also, maximum calculated workload at which tissue ADP stabilized was lower in patients than in normal subjects (88 +/- 7% vs 120 +/- 4% of maximum voluntary workload, patients vs normal subjects, P < 0.05). Time to recovery to pre-test phosphocreatine levels was prolonged by 46% in patients compared to normal subjects (P < 0.05).

CONCLUSIONS

In heart failure, oxidative fibre mitochondrial function in skeletal muscle is impaired, as reflected by the reduced phosphate potential and oxidative phosphorylation rate, early exhaustion and slowed recovery of intracellular energy reserve at workloads, which do not affect intracellular pH.

Contrasting preload-dependent hemodynamic and neurohumoral effects of isomazole, a partial phosphodiesterase inhibitor and calcium sensitizer

BACKGROUND

Currently evaluated positive inotropic agents that act predominantly through phosphodiesterase III-inhibiting properties, have been disappointing in the treatment of heart failure. Lack of efficacy as a result of diminished cellular cyclic adenosine monophosphate and vasodilating tolerance and side effects are prevalent. In contrast, calcium sensitization is preserved in heart failure and agents that combine phosphodiesterase-inhibiting and calcium-sensitizing properties may be more efficacious. Isomazole is such a novel agent with combined properties. This study investigated the acute hemodynamic and neurohormonal effects of intravenous isomazole (3 micrograms/kg/min for 30 minutes).

METHODS AND RESULTS

The effects of preexisting preload were evaluated in 18 patients with heart failure, New York Heart Association class II/III, and elevated (> 15 mmHg, n = 11, group I) and normal; (n = 7, group II) pulmonary wedge pressure at baseline. In the overall group, isomazole increased myocardial contractility and relaxation and decreased systemic resistance by 20%. Left and right filling pressures fell by 35-45%, accompanied by a 69% reduction in cardiac atrial natriuretic peptide release. In contrast, levels of arterial norepinephrine and renin both increased by 27%. Cardiac output increased in group I (23%), but fell in group II (18%), accompanied by a 51% increase in arterial norepinephrine. Cardiac atrial natriuretic peptide decreased in group I, but not in group II.

CONCLUSIONS

Isomazole induced positive inotropic and lusitropic effects and arterial vasodilation in all patients. Cardiac pump function improved only in group I, accompanied by a reduction in sympathetic activity and renin-angiotensin and aldosterone levels and a more pronounced decrease in cardiac atrial natriuretic peptide release. In contrast, in patients with normal to low preload, the further reduction in preload led to a deterioration of pump function and increased sympathetic tone.

Early administration of ramipril in acute myocardial infarction: neurohormonal and hemodynamic effects and tolerability

Although several large studies indicate a beneficial effect of angiotensin-converting enzyme (ACE) inhibitors after myocardial infarction, the optimal timing of therapy in terms of safety and the effects on neurohormones during myocardial infarction are less well known. In order to investigate the effect of ramipril, administered within 24 h after myocardial infarction, on hemodynamics and neurohormones and its safety, 20 patients with a myocardial infarction were studied. Nine patients had an anterior, 10 an inferior, and 1 a non-Q-wave infarction. Fourteen patients received thrombolytic therapy, whereas 6 did not. The initial dose of ramipril was 1.25 mg, but was gradually increased to 5 mg during the next 4 days. Side effects did not occur. The mean arterial pressure decreased 8 h after the first dose from 84 +/- 2 mm Hg (control) to 77 +/- 2 mm Hg (p < 0.05) and remained decreased thereafter. This was accompanied by a reduction in systemic resistance of 8% after 8 h and of 12% on day 2. Heart rate, cardiac and stroke indexes, and pulmonary artery and wedge pressures did not change. The ACE activity decreased within 1 h of ramipril administration with a maximum of 71% at 4 h after the second dose and remained at this level throughout the study. Angiotensin II decreased by 34% (day 2) and by 41% (day 5). The renin activity gradually increased from 33 +/- 7.5 to 75.4 +/- 11.5 microM/ml on day 5, whereas epinephrine was reduced from day 2 onwards, with a maximal reduction of 71% on day 5. Arginine vasopressin was significantly reduced 5 h after ramipril administration until the end of the study, with a maximum of 77% on day 3. Moreover, a late but significant decrease in norepinephrine occurred on day 5. Thus, oral ramipril results in early ACE inhibition, followed by progressive attenuation of the neuroendocrine activation and a reduction in afterload during the acute phase of myocardial infarction. It is well tolerated, also in combination with nitroglycerin and thrombolytic therapy.

Acute myocardial ischaemia induces cardiac carnitine release in man

In animal studies, prolonged periods of ischaemia decrease the cardiac carnitine content. However, whether in humans the heart loses carnitine during short-term ischaemia, and whether this is related to ischaemia-induced cardiac dysfunction, is as yet unknown. Carnitine kinetics were investigated in 28 normotensive patients with significant left coronary artery disease, during and after incremental atrial pacing. To evaluate carnitine kinetics from the ischaemic area, patients were grouped as those with (n = 22) or without (n = 6) myocardial lactate production. Atrial pacing resulted in a comparable maximal heart rate and ST depression in both groups. Carnitine kinetics did not change in those without lactate production. In contrast, coronary venous free carnitine levels increased significantly by 9% during pacing in those with lactate production. Cardiac free carnitine balance changed from uptake (255 +/- 107 pmol.min-1, mean +/- SEM) to release, (-150 +/- 66 pmol.min-1) at 30 min after pacing in the group with lactate production. Arterial and coronary venous differences in free carnitine were significantly correlated with myocardial lactate extraction immediately after pacing. The change in coronary venous free carnitine was significantly correlated with the change in left ventricular ejection fraction at 10 min after pacing. Thus, in patients with coronary artery disease, short-term mild myocardial ischaemia results in significant cardiac free carnitine loss.

Beta-blocking agents in heart failure. Should they be used and how?

Experience accumulated from several large trials strongly suggests that beta-blockers should be used for the management of chronic heart failure[87]. It is appropriate to add beta-blockade to conventional therapy such as diuretics, ACE inhibitors and digoxin, as this was the approach used in the major trials. It is appropriate to treat patients with mild, moderate and, when stable, severe chronic heart failure. The benefits obtained include improvements in left ventricular function, reductions in symptoms and morbidity, improvement of quality of life, and delay of clinical progression, reflected in a reduced need for cardiac transplantation and, probably, a reduction in mortality. beta-blockers are much better tolerated, when used appropriately in selected patients, than was previously supposed. To confirm the improvement in survival recently reported with carvedilol, further prospective trials using different beta-blockers are warranted. No major comparative trials have been carried out between beta-blockers in chronic heart failure, therefore it is not known whether the differences between them are clinically significant. The optimal dose of beta-blocker and the effect in patient groups excluded from or poorly represented in the clinical trials (e.g. elderly patients) have yet to be determined. Placebo-controlled mortality trials with bucindolol (BEST) and bisoprolol (CIBIS-II) are under way[89,90]. A large study of carvedilol versus metoprolol (COMET), added to conventional treatment, is planned.

Value of digoxin in heart failure and sinus rhythm: new features of an old drug?

Digoxin has been a controversial drug since its introduction >200 years ago. Although its efficacy in patients with heart failure and atrial fibrillation is clear, its value in patients with heart failure and sinus rhythm has often been questioned. In the 1980s, reports of some large-scale trials indicated that digoxin, with or without vasodilators or angiotensin-converting enzyme inhibitors, reduced signs and symptoms of congestive heart failure and improved exercise tolerance. This beneficial influence was mainly found in patients with more advanced heart failure and dilated ventricles, whereas the effect in those with mild disease appeared to be less pronounced. In the last few years, new data have shown that digoxin may also have clinical value in mild heart failure, either when used in combination with other drugs or when administered alone. As neurohumoral activation has increasingly been recognized to be a contributing factor in the disease progression of chronic heart failure, the modulating effects of digoxin on neurohumoral and autonomic status have received more attention. Also, there is evidence that relatively low doses of digoxin may be at least as effective as higher doses and have a lower incidence of side effects. Further, the recognition that the use of digoxin too early after myocardial infarction may be harmful and the development of other drugs, in particular angiotensin-converting enzyme inhibitors, have obviously changed the place of digoxin in the treatment of chronic heart failure. The large-scale survival trial by the Digitalis Investigators Group (DIG), whose preliminary results have recently been presented, has shown that although digoxin has a neutral effect on total mortality during long-term treatment, it reduces the number of hospital admissions and deaths due to worsening heart failure. The potentially new features of the old drug digoxin are discussed in this review.

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

PRIMARY OBJECTIVE

To determine the effects of pimobendan 2.5 and 5 mg daily on exercise capacity in patients with chronic heart failure.

DESIGN

A randomised, double blind, placebo controlled trial of the addition of pimobendan to conventional treatment with a minimum follow up of 24 weeks.

SETTING

Outpatient cardiology clinics in six European countries.

PATIENTS

317 patients with stable symptomatic heart failure, objectively impaired exercise capacity, and an ejection fraction of 45% or lower who were treated with at least an angiotensin converting enzyme inhibitor and a diuretic and who tolerated a test dose of pimobendan.

RESULTS

Compared with placebo, both pimobendan 2.5 and 5 mg daily improved exercise duration (bicycle ergometry) by 6% (P = 0.03 and 0.05) after 24 weeks of treatment. At that time 63% of patients allocated to pimobendan and 59% of those allocated to placebo were alive and able to exercise to at least the same level as at entry (P = 0.5). No significant effects on oxygen consumption (assessed in a subgroup of patients) and on quality of life (assessed by questionnaire) were observed. Pimobendan was well tolerated. Proarrhythmic effects (24-hour electrocardiography) were not observed. In both pimobendan groups combined the hazard of death was 1.8 (95% confidence interval 0.9 to 3.5) times higher than in the placebo group.

CONCLUSIONS

Pimobendan improves exercise capacity in patients with chronic heart failure who are also on conventional treatment. The balance between benefit and risk of treatment with this compound remains to be established however.

Economic aspects of treatment with captopril for patients with asymptomatic left ventricular dysfunction in The Netherlands

OBJECTIVE

To estimate the costs and effects of preventive treatment with captopril compared with the current treatment policy in patients with asymptomatic left ventricular dysfunction after a myocardial infarction.

METHODS

Estimates of effects are based on the results of the SAVE trial. Costs are estimated on the basis of current treatment patterns in four Dutch hospitals. All knowledge is incorporated in a mathematical model extrapolating the SAVE results to 20 years.

RESULTS AND CONCLUSIONS

Captopril treatment is expected to increase survival at certain costs. The average additional costs per patient are estimated at DF1 2,491 in 4 years and at DF1 8,723 in 20 years of treatment. Costs per additional survivor after 4 years are estimated at DF1 69,126. After extrapolation of the results of the SAVE trial to 20 years, costs per life-year gained can be estimated at DF1 15,799. From univariate sensitivity analysis it appears that the results are highly sensitive for the costs of treatment with captopril and the occurrence and prevention of clinical heart failure. Varying all estimates randomly between upper and lower limits-in 5,000 simulations-an estimate of costs per life-year gained of DF1 15,729 is made for 20 years of treatment, with 95% of all estimates between DF10 and DF1 50, 000. On a national level, undiscounted costs are expected to increase up to approximately DF1 42 million annually during the first 40 years after introduction of the preventative strategy.

Acute hemodynamic effects and preload-dependent cardiovascular profile of the partial phosphodiesterase inhibitor nanterinone in patients with mild to moderate heart failure

Nanterinone (UK-61,260) is a novel positive inotropic and balanced-type vasodilating drug, only partially based on phosphodiesterase III inhibition. Preliminary data from controlled studies suggest satisfactory long-term efficacy and safety. As its acute hemodynamic effects in humans are unknown, an oral dose of 2 mg nanterinone was studied in 14 patients with heart failure (NYHA class II-III) on chronic diuretic and angiotensin-converting enzyme (ACE) inhibitor treatment. Before the study, patients were on a 2 g salt-balanced diet, and they received their last medication 16 hours before each study day. Hemodynamic measurements were carried out before and 0.5, 1, 1.5, 2, 2.5, 3, 4, 8, 12, and 24 hours after administration of the study drug. All patients received placebo and nanterinone on 2 consecutive days. Following nanterinone, systemic vascular resistance decreased immediately from 1699 +/- 82 (mean +/- SEM) at baseline to 1368 +/- 80 at 1 hour. Changes persisted for 12 hours. Concomitantly, there was an immediate and significant fall in pulmonary wedge pressure to 38% of baseline at 1.5 hours, together with a 20% reduction in pulmonary artery pressure. Heart rate remained unchanged and arterial pressures showed only a short, significant decrease. Cardiac index rose significantly from 2.28 +/- 0.15 at baseline to a highest value of 2.65 +/- 0.14 1/min/m2 at 1 hour. Changes persisted for 3 hours. Placebo had no effect on these variables. As, in view of its potential venodilating properties, hemodynamic improvement by nanterinone may depend on pre-existing left ventricular filling pressure, patients were subsequently grouped according to baseline pulmonary wedge pressure of > 12 mmHg (H-PCWP) and < or = 12 mmHg (L-PCWP). Cardiac index improved by 26% in H-PCWP and by 17% in L-PCWP (NS). In contrast, PCWP fell more markedly in H-PWCP than in L-PCWP (40% and 23%, respectively, p < 0.05). Thus, oral nanterinone results in a significant acute hemodynamic improvement and is well tolerated. Although changes in left ventricular filling pressure are more pronounced in patients with elevated pre-existing PCWP, cardiac pump function improves equally in patients with normal or low left ventricular filling pressure at baseline.

Anti-ischaemic efficacy of L-propionylcarnitine--a promising novel metabolic approach to ischaemia?

L-propionylcarnitine, a naturally occurring derivative of L-carnitine, essential for mitochondrial fatty acid transport and high-energy phosphate exchange, acutely reduces myocardial ischaemia and improves ischaemia-induced cardiac dysfunction following intravenous administration. This randomized, crossover study was designed to compare the long-term anti-ischaemic effects of oral L-propionylcarnitine with diltiazem in patients with stable, exercise-induced angina. After a 2-week washout phase of anti-anginal medication and a 2-week single-blind placebo period, 46 patients were included in the study, 23 of whom received 1500 mg L-propionylcarnitine daily for 6 weeks, and 23 diltiazem (180 mg daily for 3 weeks, followed by 360 mg daily for 3 weeks), crossing over to the other treatment after a 1-week washout period. Three patients on L-propionylcarnitine and two on diltiazem discontinued. Both treatments resulted in comparable exercise duration (582 +/- 35 s and 588 +/- 33 s, mean +/- SEM), time to 0.1 mV ST depression (436 +/- 38 s and 465 +/- 36 s), and increase in time to 0.1 mV ST depression from baseline (20% and 28%), L-propionylcarnitine and diltiazem, respectively. Diltiazem decreased the rate-pressure product at rest and exercise, L-propionylcarnitine did not. Both compounds significantly reduced ST depression at maximal exercise [23% (L-propionylcarnitine) vs 35% (diltiazem), P < 0.05 diltiazem vs L-propionylcarnitine]. Diltiazem increased the time to onset of angina by 22%. In contrast, no significant changes occurred with L-propionylcarnitine. During the study, anginal attacks were reduced by 70% and 57%, and nitroglycerin consumption decreased by 57% and 70%, L-propionylcarnitine and diltiazem, respectively. Thus, both L-propionylcarnitine and (high-dose) diltiazem result in anti-ischaemic effects and decrease anginal attacks in daily life. Although the effect of diltiazem on exercise-induced ischaemia appears more pronounced than that of L-propionylcarnitine, this novel metabolic approach to ischaemia warrants further development.

Additional antiischemic effects of long-term L-propionylcarnitine in anginal patients treated with conventional antianginal therapy

Cardiac L-carnitine content, essential for mitochondrial fatty acid transport and ATP-ADP exchange, decreases during ischemia. In animal models, administration of the natural derivative, L-propionylcarnitine, may reduce ischemia and improve cardiac function. To evaluate possible antiischemic effects of L-propionylcarnitine was compared with placebo in a randomized, double-blind, parallel design, in addition to preexisting therapy. Patients with > or = 2 anginal attacks per week and objective signs of ischemia with angina during bicycle exercise testing were included. After an initial 2-week, single-blind placebo phase, 37 patients received 500 mg L-propionylcarnitine tid, and 37 patients received placebo for 6 weeks. Both groups were comparable at baseline. Three patients discontinued the study while on placebo (two because of noncompliance, one because of palpitations) and one while on L-propionylcarnitine (noncompliance). Although heart rate, blood pressure at rest, and maximal exercise were not affected, L-propionylcarnitine increased the time to 0.1 mV ST-segment depression [44 +/- 3 vs. 8 +/- 2 seconds (mean +/- SEM) in the placebo group; p = 0.05], and exercise duration improved by 5% compared with placebo. Anginal attacks and the consumption of nitroglycerin were not affected in either group. Thus, following a 6 week treatment period, L-propionylcarnitine induced additional, albeit marginal, antiischemic effects in anginal patients who were still symptomatic despite maximal conventional antianginal therapy. It is questionable whether in these patients this form of metabolic treatment will achieve great benefit, although in some improvement can be expected.

Neurohormonal modulation in heart failure: ACE inhibition and beyond

Angiotensin converting enzyme (ACE) inhibition undoubtedly has become the cornerstone of heart failure treatment. Useful in each stage, it should possibly be considered first-line treatment in many patients with mild heart failure in whom fluid retention is not clearly present. Careful consideration of the optimal dose for the individual is important. Until further data are available concerning the efficacy and tolerability of high and low doses, the clinician should consider the target doses used in large controlled heart failure trials. Even under optimal dosing conditions, it is likely that ACE inhibition may not suffice in completely modulating the extensive neurohormonal stimulation extant in heart failure. In part this may result from a breakthrough of the ACE inhibitor effect as well as from activation of hormones and peptides that may not be affected by ACE inhibition. Also, a substantial proportion of patients may not tolerate sufficient ACE inhibition. Alternative or additional therapy aimed at modulating neurohormonal activation concerns interference with other parts of the renin angiotensin system, such as angiotensin II receptor and aldosterone receptor antagonism. Sympathetic activity and catecholamine levels may decrease with dopaminergic D2 agonists and, possibly, beta-blockade; in the latter, this may be confined to patients with pre-existing sympathetic over-activation. Increasing circulating levels of atrial natriuretic peptide via neutral endopeptidase inhibition may offer an alternative way to increase diuresis and natriuresis without neuroendocrine stimulation. Novel possibilities that have not yet been tested sufficiently in patients with heart failure include endothelin receptor antagonism, arginine vasopressin antagonism, and renin inhibition. Finally, digitalis glycosides may be considered neurohormonal modulators in addition to being positive inotropes. Heart failure is a complex condition that involves many organs and systems besides the heart. Polypharmacy tailored to the individual is mandatory. It is thus necessary to investigate approaches to the modulation of neurohormonal activation beyond ACE inhibition.

Anti-ischaemic effects of converting enzyme inhibitors: underlying mechanisms and future prospects

ACE inhibitors have the potential to affect myocardial ischaemia in patients with asymptomatic ventricular dysfunction and ischaemic cardiomyopathy after long-term treatment. However, anti-ischaemic effects are virtually absent in stable effort angina during short-term therapy, which suggests different mechanisms of action in different patient subtypes. Long-term treatment in left ventricular dysfunction may lead to a reduction in myocardial oxygen demand and ischaemia as a result of ventricular remodelling, possibly supported by structural coronary vascular effects, i.e., an improved endothelial function and vasodilator capacity. An alternative mechanism by which ACE inhibitors may affect ischaemia, is through modulation of ischaemia-induced neurohormonal activation and subsequent systemic vasoconstriction. Depending on the severity of ischaemia, pronounced catecholamine activation and stimulation of the circulating renin-angiotensin system occur, accompanied by systemic vasoconstriction and an increase in afterload. These changes are marked in patients with left ventricular dysfunction. Moreover, a change from net catecholamine release to uptake in the ischaemic area is observed. Although the clinical significance of the latter observation is still unclear, sympathetic activation may lead to coronary vasoconstriction in stenotic areas where normal endothelium-dependent coronary vasodilatation has become impaired. In the resting patient, enalaprilat and perindoprilat significantly reduce myocardial ischaemia, not by a direct effect on the oxygen supply-demand ratio, but through modulation of neurohormonal activation, in particular of sympathetic activation during ischaemia, and, subsequently, by preventing systemic vasoconstriction. These effects are pronounced in left ventricular dysfunction, at least where perindoprilat is concerned. The possibility that ACE inhibitors improve endothelial function in concert with their modulating effects on ischaemia-induced neurohormonal activation and hence influence the occurrence of myocardial ischemia during long-term treatment needs further evaluation.

[Consensus heart failure. Centraal Begeleidingsorgaan voor de Intercollegiale Toetsing]

Consensus heart failure--On June 17th, 1994, a consensus meeting was organised to establish guidelines for the diagnosis and treatment of heart failure. Reason to do this were controversies, especially among general practitioners, cardiologists, internists and gerontologists, which arise as a consequence of new diagnostic modalities (such as echocardiography) and altered aims of the treatment (besides relief of symptoms reduction of morbidity and mortality). A number of starting points were formulated by a preparatory committee: Heart failure constitutes a major health problem. It is defined by cardiac dysfunction with accompanying symptoms. Diagnosis and treatment should focus first on causes or contributing factors. The extent of diagnostic procedures depends on possible doubts with regard to diagnosis and aetiology and therapeutic consequences. Treatment should include non-medical measures. Apart from relief of symptoms, the choice of drugs is also determined by their potential to reduce morbidity and mortality. The pharmacotherapeutic approach has to be tailored to the needs of the patient with a central role for the ACE inhibitors. Patients with concomitant arrhythmias and (very) old patients form separate risk groups. Further attention should be paid to the prevention of heart failure.

Long-term vasodilator treatment with flosequinan does not lead to hemodynamic tolerance or neurohormonal activation in severe heart failure

Flosequinan is a balanced-type vasodilator with a prolonged mode of action due to an approximate 38-hour half-life of its active first metabolite, BTS 53554. As this may lead to tolerance and neurohormonal activation, the acute and long-term pharmacokinetic, hemodynamic, and neurohormonal profile of flosequinan was evaluated. On three consecutive days, 23 patients with heart failure (New York Heart Association classes II-IV), despite digitalis and diuretics, underwent invasive hemodynamic studies after receiving 100 mg oral flosequinan (day 1), placebo (day 2), and 100 mg flosequinan (day 3), followed by repeat invasive evaluation after long-term flosequinan (100 mg daily) for 17 +/- 2 weeks. On each study day, plasma flosequinan levels increased to 1.9 +/- 0.2 mg/L after 1 hour, but returned to baseline levels at 24 hours. In contrast, BTS 53554 increased progressively, reaching relatively high plateau levels (6 mg/L) during chronic therapy. First-dose flosequinan decreased the pulmonary wedge, right atrial pressure, and systemic resistance by 50, 60, and 22%, respectively, whereas the cardiac index was increased by 40%; these effects lasted for 48 hours. During long-term treatment, baseline values of the pulmonary wedge and right atrial pressure were comparable to prestudy values, whereas systemic resistance had decreased by 22%, and the cardiac index and heart rate had increased by 22 and 14%, respectively. Readministration of flosequinan did not further affect hemodynamics, apart from a moderate reduction in the pulmonary wedge and right atrial pressure. Neurohumoral activation did not occur during acute or long-term therapy. Thus, although changes in left and right heart filling pressures are attenuated during long-term treatment, flosequinan induces sustained arterial dilatation and improves cardiac pump function without activation of circulating neurohormones.

Therapeutic strategies and neurohormonal control in heart failure

Neurohormonal activation is one of the major determining factors in the process of transition from asymptomatic ventricular dysfunction to end-stage heart failure, in the prognosis of heart failure, and in the efficacy and, hence, choice and timing of pharmacological therapy. Although various counteracting hormonal systems are involved, emphasis in terms of functionality is on vasopressor and growth-promoting systems. In contrast, ANF and N-terminal proANF probably have a significant prognostic value, even at an early stage. The focus of heart failure therapy is moving from measures aimed at improving cardiac function to ones that concentrate on modulating neuroendocrine changes during failure and their effects on intrinsic peripheral and cardiac alterations. Although ACE inhibition undoubtedly constitutes a major step forward in this approach, alternative ways to modulate neurohormonal activation pharmacologically are needed. Several such novel approaches are being developed, including angiotensin receptor antagonists, dopaminergic stimulation, neutral endopeptidase inhibition, aldosterone antagonism and beta blockade. In addition to their positive inotropic properties digitalis glycosides may act as neurohormonal modulators. Finally, the realization that several well-established forms of heart failure therapy may aggravate neuroendocrine stimulation demands careful consideration as to whether such agents are really necessary, and underlines the desirability of co-administering neurohormonal modulating therapy.

Hemodynamic, neurohumoral, and myocardial energetic effects of pimobendan, a novel calcium-sensitizing compound, in patients with mild to moderate heart failure

In contrast to cyclic AMP-dependent positive inotropes, the calcium-sensitizer and partial phosphodiesterase (PDE) inhibitor pimobendan may induce beneficial effects in heart failure. However, its effect on relaxation, myocardial energetics and neurohormones are unknown. Twelve patients with heart failure, New York Heart Association (NYHA) classification II-III, due to ischemic cardiomyopathy, were studied for 1 h after they received 5 mg pimobendan intravenously (i.v.). Pimobendan progressively reduced systemic resistance and left ventricular end-diastolic pressure (LVEDP) (22 and 50%, respectively) and improved isovolumetric contractility and relaxation parameters by 30% (all p < 0.05 vs. control). LV end-diastolic and end-systolic volumes (LVEDV, LVESV) decreased significantly by 20 and 19%, respectively. Cardiac output (CO) increased by 17% due to a simultaneous increase in heart rate (HR) from 75 +/- 3 to 86 +/- 5 beats/min (mean +/- SEM, p < 0.05). Pimobendan did not change coronary hemodynamics, but myocardial O2 extraction and consumption were decreased significantly by 18 and 20%, respectively. Catecholamines, angiotensin II (AII), and aldosterone levels did not change significantly. In contrast, arterial and coronary venous renin increased significantly from 57 +/- 17 and 53 +/- 14.7 microM/h at control to 69 +/- 20 and 69 +/- 20 microM/h, respectively, 60 min after pimobendan administration. Simultaneously, cardiac renin uptake at baseline (0.449 +/- 0.185 mumol/min) changed to release (-0.071 +/- 0.145 mumol/min, p < 0.05). Serious side effects did not occur. Thus, pimobendan had progressive positive inotropic and lusitropic effects, diminished preload and afterload despite modest stimulation of plasma renin activity (PRA), and reduced systemic vascular resistance.(ABSTRACT TRUNCATED AT 250 WORDS)