Candesartan in heart failure--assessment of reduction in mortality and morbidity (CHARM): rationale and design. Charm-Programme Investigators

Clinical features and contemporary management of patients with low and preserved ejection fraction heart failure: baseline characteristics of patients in the Candesartan in Heart failure-Assessment of Reduction in Mortality and morbidity (CHARM) programme

AIMS

To describe the clinical characteristics and contemporary treatment of a broad spectrum of patients with chronic heart failure (CHF) randomised in the Candesartan in Heart failure-Assessment of Reduction in Mortality and morbidity (CHARM) programme, consisting of three component studies comparing placebo to candesartan.

METHODS AND RESULTS

CHARM Alternative, CHARM Added and CHARM Preserved enrolled 2028 low left ventricular ejection fraction (LVEF) ACE inhibitor intolerant patients, 2548 low LVEF ACE inhibitor treated patients and 3025 preserved LVEF patients, respectively. Patients in CHARM Preserved were more often female. The proportion of women in CHARM Preserved was 40% compared to 32% in CHARM Alternative and 21% in CHARM Added. Patients in CHARM Preserved were also more often hypertensive than in the other two trials (64% vs. 50% and 48%, respectively). Symptoms and signs (with the exception of a third heart sound) were similar in all three patient groups. Beta-blockers were used in over half of patients in all three groups. Digoxin and spironolactone were used less frequently and calcium antagonists more frequently in CHARM Preserved. Spironolactone was used most frequently in CHARM Alternative, i.e. in ACE inhibitor intolerant patients.

CONCLUSIONS

The CHARM Programme provides the largest and most detailed comparison to date of patients low- and preserved-LVEF CHF. It also describes the causes of ACE-inhibitor intolerance in a large cohort of patients and the other treatment which these patients receive.

Angiotensin II receptor blockers and cardiovascular outcomes: what does the future hold?

The ability of angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) to lower blood pressure (BP) is well established. ACE inhibitors (ACE-Is) have also been shown to improve the prognosis of a broad range of patients at high cardiovascular risk, including those with heart failure, post-myocardial infarction (MI), and nephropathy. These benefits suggest that interrupting the renin-angiotensin-aldosterone system (RAAS) with ACE-Is has a widespread vasculoprotective effect, provided that BP is also adequately controlled. Evidence that RAAS blockade by ARBs also improves long-term clinical outcomes in patients with cardiovascular disease has started to accumulate, and will be tested further during the coming years as a number of large-scale, prospective trials are completed. These trials are investigating the long-term protective effects of ARBs on morbidity and mortality in patients with hypertension, heart failure, diabetes mellitus, acute MI, or established vascular disease. The results should establish the extent to which ARBs exhibit the vasculoprotective properties demonstrated by ACE-Is in patients at high cardiovascular risk. If ARBs are found to provide benefits that are similar to, or even greater than ACE-Is, it may have important implications for drug selection, given the excellent tolerability of ARBs. Some studies are also investigating whether more extensive RAAS blockade using a combination of an ARB and an ACE-I will offer even greater protection than either agent alone.

Cardiac hormones as diagnostic tools in heart failure

In patients with heart failure, plasma levels of atrial natriuretic peptide (ANP), B-type natriuretic peptide (BNP), and the N-terminal fragments of their prohormones (N-ANP and N-BNP) are elevated, because the cardiac hormonal system is activated by increased wall stretch due to increased volume and pressure overload. Patients suspected of having heart failure can be selected for further investigations on the basis of having an elevated plasma concentration of N-ANP, BNP, and N-BNP. High levels of cardiac hormones identify those at greatest risk for future serious cardiovascular events. Moreover, adjusting heart failure treatment to reduce plasma levels of N-BNP may improve outcome. Cardiac hormones are most useful clinically as a rule-out test. In acutely symptomatic patients, a very high negative predictive value is coupled with a relatively high positive predictive value. Measurement of cardiac hormones in patients with heart failure may reduce the need for hospitalizations and for more expensive investigations such as echocardiography. However, there have also been conflicting reports on the diagnostic value of cardiac hormones, they are not specific for any disease, and the magnitude of the effects of age and gender on BNP in the normal subgroup suggests that these parameters need to be considered when interpreting cardiac hormone levels.

New developments in the pharmacological treatment of chronic heart failure

In recent years, rapid growth in the understanding of the pathophysiology of chronic heart failure has allowed for insights into many potential new therapeutic strategies. Yet until now, despite sound biological basis for efficacy and success in early-Phase studies, novel agents have not stood up to the scrutiny of late-Phase clinical trials. Indeed, remarkably negative results have been observed for vasopeptidase inhibitors, endothelin receptor antagonists and agents which block immune activation. However, efficacy data from other novel agents are still awaited, including the selective aldosterone receptor antagonist eplerenone, arginine vasopressin inhibitors, erythropoietin and hydroxy-methyl-glutaryl coenzyme A reductase inhibitors. Other classes of drugs which may enter clinical development include cardiac metabolic agents, matrix metalloproteinase inhibitors and advanced glycation end product antagonists. That the mortality and morbidity of patients with chronic heart failure remain unacceptably high makes the ongoing commitment to exploration of new drug therapies for the condition critical.

Improving clinical outcomes with drug treatment in heart failure: what have trials taught?

Pharmacologic clinical trials in heart failure (HF) have provided substantial advances in effective treatment of this condition, moving us from our focus on short-term symptom relief to an expectation of substantial improvement in long-term clinical outcomes for our patients. Based on an appreciation of the importance of neurohormonal activation in the pathophysiology of HF, clinical trials have demonstrated the value of angiotensin-converting enzyme (ACE) inhibitors and beta-blockers in impeding the progression of HF and in reducing morbidity and mortality for patients with this condition. Clinical trials have further demonstrated the benefits of digoxin in improving symptoms and reducing hospitalization frequency, as well as in aldosterone blockade, at least in patients with severe symptoms. Given the ethical imperative to treat with ACE inhibitors, the angiotensin receptor antagonists have been difficult to study; nevertheless, their value is becoming increasingly clear, particularly for patients intolerant of ACE inhibitors. Trials with several classes of newer agents-cytokine antagonists, endothelin receptor blockers, and vasopeptidase inhibitors-have recently yielded disappointing results. Early results with vasopressin receptor antagonists provide some promise of long-term benefit. Clinical trials have provided significant treatment advances; ongoing and future trials will demonstrate the degree to which we can improve on what we have achieved to date with pharmacologic treatments.

Therapeutic role of angiotensin II receptor blockers in the treatment of heart failure

Angiotensin II type 1 receptor blockers (ARBs) are generally as effective as angiotensin-converting enzyme (ACE) inhibitors in patients with hypertension. However, inhibition of angiotensin is not achieved completely through the blocking effects of ACE inhibitors, and the possibility of a non-ACE pathway for generation of angiotensin II has important implications for treating cardiovascular disease. The selective quality of ARBs for the angiotensin II type 1 (AT1) receptor may confer an advantage. In a recently reported trial, the ARB valsartan substantially improved patients' New York Heart Association class, clinical signs and symptoms, and quality of life and provided morbidity and mortality benefits in selected patients. Valsartan was recently approved to treat heart failure in patients who cannot be maintained on an ACE inhibitor. As a class, ARBs are well tolerated and have a good safety profile.

ACE inhibitors and ARBs in chronic heart failure: the established, the expected, and the pragmatic

ACE inhibitors have been shown to reduce mortality, reduce hospitalization, reduce symptoms, and increase exercise capacity in patients with heart failure and a large heart (low ejection fraction). The evidence is overwhelming. There are some subgroups of patients, such as the very elderly and those with a normal ejection fraction, where uncertainty still exists. The combination of a diuretic and an ACE inhibitor is currently the proper treatment of congestive heart failure; a beta-blocker should be added in selected patients. The evidence for the efficacy of ARB is less persuasive and, for the present, this class of drug should be prescribed only when an ACE inhibitor cannot be tolerated. The results of the trials emphasize an emerging problem in medicine, namely how to evaluate a new treatment that may be as efficacious as current therapy but with fewer side-effects. Proving equivalence in efficacy will be difficult, requiring large studies comparing new drugs with the best current treatment. The most common etiology of heart failure is coronary heart disease. If further studies provide more support for the idea that ACE inhibitors prevent ischemic episodes and delay the onset of heart failure, then a new indication for ACE inhibitors will be the prevention of heart failure.

Angiotensin II receptor blockers in heart failure

Heart failure remains a significant cause of morbidity and mortality, despite major advances in therapy. Angiotensin II, the principal mediator of the renin-angiotensin system, exerts both short-term (e.g., hemodynamic, renal) and long-term (e.g., inflammation, cardiac remodeling) effects in the pathophysiology of cardiovascular disease. The effects of angiotensin II appear to be more completely inhibited by angiotensin II receptor blockers (ARBs), which act at the subtype 1 receptor level, than by angiotensin-converting enzyme (ACE) inhibitors because pathways other than that of ACE contribute to the generation of angiotensin II. Evidence demonstrates that ARBs, when added to conventional treatment for patients with heart failure, are associated with a reduction in morbidity and mortality as well as an improvement in quality of life. Clinical trials of ARB therapy indicate that these agents are generally well tolerated, both alone and in combination with other neurohormonal inhibitors. The current role of ARBs in heart failure is as an alternative for patients who cannot tolerate therapy with an ACE inhibitor. A number of ongoing clinical studies are likely to further define or expand the role of ARBs in the treatment of cardiovascular disease.

Candesartan Antihypertensive Survival Evaluation in Japan (CASE-J) Trial of Cardiovascular Events in High-Risk Hypertensive Patients: Rationale, Design, and Methods

Hypertension continues to be a major public health issue in the world. To combat this problem, many anti-hypertensive drugs have been developed and proven effective at controlling blood pressure in the last half century. In recent decades, antihypertensive drugs have been shown to have cardiovascular benefits beyond the reduction of blood pressure, and the focus has shifted to clarification of these effects. Angiotensin II receptor antagonists and calcium channel blockers are the most widely used antihypertensive drugs in Japan. However, these two classes of drugs have not yet been compared with respect to their efficacy for treating cardiovascular events. The Candesartan Antihypertensive Survival Evaluation in Japan (CASE-J) trial described herein is a prospective, multicenter, randomized, open-label, active-controlled, 2-arm parallel group comparison with a response-dependent dose titration and blinded assessment of endpoints in high-risk hypertensive patients treated with either an angiotensin II receptor antagonist (candesartan cilexetil) or a third-generation calcium channel blocker (amlodipine besilate). The eligibility criteria in this study were 1) age between 20 and 85 years; 2) systolic blood pressure (SBP) > or = 140 mmHg in those below 70 years of age or > or = 160 mmHg in those above 70 years of age or diastolic blood pressure (DBP) > or = 90 mmHg on two consecutive measurements at clinic; and 3) at least one of the following high risk factors for cardiovascular events: a) SBP > or = 2180 mmHg or DBP > or = 110 mmHg on two consecutive visits, b) type 2 diabetes mellitus (fasting blood glucose > or = 126 mg/dl, casual blood glucose > or = 200 mg/dl, HbA1c > or = 6.5%, 2 h blood glucose on 75 g oral glucose tolerance test (OGTT) > or = 200 mg/dl, or current treatment with hypoglycemic therapy), c) history of cerebral hemorrhage, cerebral infarction, or transient ischemic attack until 6 months prior to the screening, d) left ventricular hypertrophy on either echocardiography or ECG, angina pectoris, or history of myocardial infarction until 6 months prior to screening, e) proteinuria or serum creatinine > or = 1.3 mg/dl, and f) symptoms of arteriosclerotic artery obstruction. The therapeutic goals of blood pressure control were set as follows: SBP < 130 mmHg and DBP < 85 mmHg for patients below 60 years of age, SBP < 140 mmHg and DBP < 90 mmHg for those in their 60s, SBP < 150 mmHg and DBP < 90 mmHg for those in their 70s, and SBP < 160 mmHg and DBP < 90 mmHg for those in their 80s. A total of 3,200 patients, equally allocated to each of the two treatment arms, were required based on a two-sided alpha level 0.05 and 90% power. The CASE-J is also the first study to employ the newly developed Automatic Bar Code Data-Capturing/Allocation, Booking & Trial Coding, Data Management (ABCD) system for data collection and management. Enrollment of patients started in September 2001 and ended in December 2002. Follow-up data will be collected every 6 months until December 2005. The CASE-J trial will provide important evidence on the comparative effectiveness of candesartan cilexetil and amlodipine besilate on cardiovascular morbidity and mortality among Japanese. In addition, the use of the ABCD system is expected to contribute to the development of more efficient data management systems for large-scale clinical trials.

The role of angiotensin II receptor blockers in the treatment of heart failure patients

Evidence from large, randomized, controlled clinical trials supports the use of angiotensin-converting enzyme (ACE) inhibitors, beta blockers, and spironolactone to reduce mortality and morbidity. Despite these effective therapies, event rates related to heart failure remain high. Although ACE inhibitors reduce angiotensin II production, they do not fully suppress the increased angiotensin II production in heart failure. Angiotensin II receptor blockers (ARBs) directly block the effect of angiotensin II, derived from any source, at the receptor level and have the potential to be as effective or even more effective than ACE inhibitors. The results of a number of clinical studies have demonstrated ARBs are effective and well tolerated. However, no studies have demonstrated a convincing decrease in mortality with ARB use, although a decrease has been observed for heart failure hospitalization. The results from further studies are awaited to clarify the role of ARBs in the treatment of heart failure.

Renin angiotensin aldosterone and adrenergic modulation in chronic heart failure: contemporary concepts

Whereas the earlier conceptual targets of heart failure therapy, such as the cardio-renal and hemodynamic models, all fulfilled the basic needs of symptomatic relief and hemodynamic improvement, only the neurohormonal model has provided an effective target to address symptom relief in concert with survival benefits. Recent data allude to a disease-modifying effect of angiotensin-converting enzyme inhibitors (ACE-Is) in retarding the new development of heart failure in high-risk populations. Angiotensin receptor antagonists (ARBs) have not been demonstrated to be superior to ACE-Is and their value in achieving incremental benefits in addition to ACE-Is is limited to scenarios in which beta-adrenergic receptor blocker therapy is not applicable. Beta-adrenergic receptor blockade in addition to ACE inhibition offers incremental benefits that are achieved early and are beneficial in most stages of severity except in the presence of overt decompensation. Unlike ACE-Is, beta-adrenergic receptor blockers cannot be construed as a class but are heterogeneous in their therapeutic response.

Amlodipine versus Angiotensin-receptor blockers for nonhypertension indications

OBJECTIVE

To review the efficacy and safety data of amlodipine and the angiotensin-receptor blockers (ARBs), focusing on heart failure, angina, percutaneous coronary intervention (PCI), and renal protection.

DATA SOURCE

A MEDLINE search (1966-December 2001) was completed using amlodipine, angiotensin-receptor antagonist, losartan, valsartan, candesartan, and telmisartan as key words. English-language articles were identified and included.

STUDY SELECTION AND DATA EXTRACTION

All identified articles were evaluated. Articles representative of the subject matter of our review were included.

DATA SYNTHESIS

Amlodipine and the ARBs lower blood pressure to a similar extent. Amlodipine is an effective antianginal agent, whereas ARBs are not. However, amlodipine is not effective in the treatment of heart failure; ARBs may be useful in this setting. ARBs are also effective in preserving renal function and may provide some protection from restenosis in patients who have had a PCI. The ARBs may also be useful in preventing both diabetic and nondiabetic nephropathy.

CONCLUSIONS

Concomitant disease states should be considered when choosing between an ARB and amlodipine for the management of hypertension.

Effects of valsartan on morbidity and mortality in patients with heart failure not receiving angiotensin-converting enzyme inhibitors

OBJECTIVES

A subgroup analysis of the Valsartan Heart Failure Trial (Val-HeFT) was performed to evaluate the effects of the angiotensin II receptor blocker, valsartan, in the patients with chronic heart failure (HF) not receiving angiotensin-converting enzyme (ACE) inhibitors.

BACKGROUND

The ACE inhibitors reduce mortality and morbidity in patients with HF. Nonetheless, nearly 20% of potentially eligible patients may not be prescribed ACE inhibitors.

RESULTS

Val-HeFT was an international, randomized, double-blinded trial that compared valsartan with placebo when added to the prescribed treatment of patients with HF. The two primary end points of the study were all-cause mortality and the composite of all-cause mortality and morbidity (sudden death with resuscitation, hospital admission for HF, or administration of intravenous inotropic or vasodilator drugs for >or=4 h without hospital admission). Of the 5,010 patients enrolled in the trial, 366 (7.3%) were not treated with ACE inhibitors at baseline. The effects of valsartan on the primary and secondary end points of the study were assessed in this subgroup of patients.

RESULTS

Both all-cause mortality and combined mortality and morbidity for patients not treated with ACE inhibitors were significantly reduced in the valsartan treatment group compared with the placebo group (17.3% vs. 27.1%, p = 0.017 and 24.9% vs. 42.5%, p < 0.001, respectively). Consistent with the data on clinical events, patients randomized to valsartan showed improvements in physiologic variables, such as ejection fraction, left ventricular internal diameter in diastole, and plasma neurohormone levels. Permanent discontinuation of study treatment because of adverse experiences was comparable between the two groups.

CONCLUSIONS

Val-HeFT has provided the first placebo-controlled outcome data demonstrating a favorable effect of an angiotensin receptor blocker on mortality and morbidity in patients with HF not treated with ACE inhibitors. Based on these results, valsartan appears to be an effective therapy in ACE inhibitor-intolerant patients.

Vascular and cardiac benefits of angiotensin receptor blockers

Angiotensin II not only is a vasoconstrictor, but it also affects cell growth and apoptosis, inflammation, fibrosis, and coagulation. Blockade of the renin-angiotensin system, either with inhibitors of the generation of angiotensin (angiotensin-converting enzyme [ACE] inhibitors) or with blockers of angiotensin receptors, reduces blood pressure and inhibits other pathophysiological actions. These other effects provide benefits in coronary heart disease, heart failure, diabetic nephropathy, and stroke beyond blood pressure reduction. These benefits were first demonstrated with ACE inhibitors. However, the mechanism of action of angiotensin receptor blockers, which block angiotensin II stimulation at the angiotensin type 1 receptor but not at the type 2 receptor, may have advantages, particularly for endothelial dysfunction and vascular remodeling, as well as cardiac and renal protection. Recent multicenter trials suggest that ACE inhibitors and angiotensin receptor blockers may reduce morbidity and mortality associated with cardiovascular and renal disease beyond blood pressure reduction. Several studies with different angiotensin receptor blockers, including comparisons with ACE inhibitors, are under way, and should provide further guidance for their clinical use.

Angiotensin II receptor blockers in the treatment of heart failure

Heart failure treatment centers on antagonism of the renin-angiotensin-aldosterone system and adrenergic nervous system. Angiotensin-converting enzyme (ACE) inhibitors have been shown to benefit patients with left ventricular systolic dysfunction irrespective of symptoms. Despite ACE inhibitor use, left ventricular dysfunction continues to progress in most patients. In addition, ACE inhibitors are substantially underused in patients who would benefit, in large part due to physician concern over potential adverse effects. Angiotensin receptor blockers (ARBs) have been proposed as either potential substitutes for ACE inhibitors or as additive therapy for heart failure patients. The authors will review the importance of the renin-angiotensin-aldosterone system in the progression of heart failure, as well as the mechanisms by which ACE inhibitors and ARBs counteract this effect. The clinical evidence to date supporting the use of ARBs in heart failure also will be reviewed. Based on current trials, ARBs are suitable substitutes for ACE inhibitors in patients who have true ACE inhibitor intolerance, but ACE inhibitors should still be considered first-line therapy in the treatment of left ventricular systolic dysfunction and heart failure. ARBs are a reasonable additive therapy in patients on maximal ACE inhibitor therapy who remain symptomatic, especially in patients unable to tolerate beta blockade.

The status of hypertension management in Japan in 2000

To evaluate the current status of the management of hypertensive patients in Japan, we investigated 907 treated hypertensive patients (486 females and 421 males; mean age, 66.7 years) followed by cardiologists. According to the guidelines for the management of hypertensive patients in Japan in 2000 (JSH-2000), only 41.5% of the subjects achieved the target blood pressure, with a mean systolic blood pressure of 140.0+/-14.9 mmHg and a mean diastolic blood pressure of 80.0+/-10.7 mmHg. There were no differences between patients with and without concurrent disease or among age groups (<60, 60-69, 70-79, and 80 years and over) in systolic blood pressure levels achieved. However, the diastolic blood pressure decreased with age, indicating an increase of the pulse pressure. Overall, the prescription rates were: calcium channel blockers (CCBs), 73.0%; angiotensin converting enzyme inhibitors (ACE-inhibitors), 31.3%; angiotensin receptor blockers (ARBs), 18.9%; beta-blockers, 16.2%; and diuretics, 10.1%. Although some selection of antihypertensive drugs was based on evidence from previous trials on hypertensive patients with diabetes mellitus, chronic heart failure and renal insufficiency, overall, CCBs were selected in all age groups and in all comorbid conditions. In conclusion, Japanese cardiologists do not appear to consider age and comorbidity when choosing antihypertensive managements. Based on current evidence, the management of hypertension should be individualized, with the blood pressure target level and antihypertensive medications chosen on the basis of age and comorbidity.

Angiotensin II receptor antagonists in chronic heart failure: where do they fit?

Heart failure is a common and disabling condition with a dismal prognosis. Inhibition of the renin-angiotensin-aldosterone system (RAAS) with angiotensin converting enzyme (ACE) inhibitors has proven to be a valuable therapeutic strategy in this condition, with well-proven morbidity and mortality benefits. Nonetheless, ACE inhibitors provide incomplete blockade of the RAAS and also inhibit the degradation of bradykinin. Although increased levels of bradykinin may have haemodynamic advantages by contributing to vasodilatation, they may also be largely responsible for some of the adverse effects of ACE inhibitors. Angiotensin II (Ang II) receptor antagonists offer more complete blockade of the RAAS without the potentiation of bradykinin, and it was therefore hoped that they would provide even greater benefits for patients with heart failure. So far, much of the initial promise of the Ang II receptor antagonists in heart failure has not been realised. There has been no conclusive demonstration of their superiority to ACE inhibitors in their effects on morbidity and mortality, and their equivalence to ACE inhibitors has not been proven. The Ang II receptor antagonists have, however, proven to be better tolerated than ACE inhibitors and they are therefore likely to be a reasonable alternative for those patients with heart failure who cannot tolerate ACE inhibition. Recent evidence has indicated that the Ang II type 1 receptor antagonist valsartan is of value when used in patients already receiving either an ACE inhibitor or a beta-blocker, but has also suggested that giving all three drugs together is deleterious. Further evidence about the value of Ang II receptor antagonists in heart failure may be provided by further studies, of which several are currently ongoing.

The Use of Angiotensin-II Receptor Blockers in Heart Failure

Angiotensin-II receptor blockers (ARBs) have recently been evaluated in large trials to determine their role in the treatment of heart failure. It is clear that angiotensin-converting enzyme inhibitors (ACE-Is) prevent the effects of an overactive renin-angiotensin aldosterone system and therefore prevent disease progression. Despite this evidence, intolerance (eg, cough) limits the use of ACE-Is in heart failure patients. Improved tolerability makes ARBs attractive alternatives in patients intolerant to ACE-Is. ARBs are also hypothesized to have additional benefits when used in combination with ACE-Is through more complete inhibition of angiotensin-II. However, studies of ARBs in patients with heart failure have not confirmed this hypothesis. This article describes the rationale and evaluates the literature for the use of ARBs in heart failure.

Current perspectives for AT(1)-receptor blockers in the management of heart failure

Despite improvements in therapy, long-term mortality remains high in patients with heart failure and thus there remains a need for new treatment strategies to reduce the burden of mortality and morbidity associated with this condition. AT(1)-receptor blockers represent a rational approach to the management of heart failure, and have been shown to have beneficial effects on heart failure symptoms and exercise tolerance. However, the two outcome trials reported to date have not shown conclusive evidence of improvements in mortality. The potential benefits of AT(1)-receptor blockers in heart failure are currently being investigated in several trials. The CHARM programme (Candesartan in Heart failure - Assessment of Reduction in Mortality and morbidity) is the largest heart failure trial so far. This comprises three trials: CHARM Alternative, in patients with left ventricular dysfunction who are intolerant to ACE inhibitors; CHARM Added, in patients with left ventricular dysfunction who are also receiving ACE inhibitors; CHARM Preserved, in patients with preserved left ventricular systolic function (ejection fraction >40%). The primary end point will be a composite of cardiovascular mortality and hospitalisation for the treatment of heart failure. Other trials are currently investigating the effects of AT(1)-receptor blockers when used as an alternative or in addition to ACE inhibitors. The CHARM programme, together with other studies, should clarify the role of these agents in the management of heart failure.

Present and future pharmacotherapy for heart failure

The pharmacotherapy currently recommended by the American College of Cardiology and the American Heart Association for heart failure (HF) is a diuretic, an angiotensin-converting enzyme inhibitor (ACEI), a beta-adrenoceptor antagonist and (usually) digitalis. This current treatment of HF may be improved by optimising the dose of ACEI used, as increasing the dose of lisinopril increases its benefits in HF. Selective angiotensin receptor-1 (AT(1)) antagonists are effective alternatives for those who cannot tolerate ACEIs. AT(1) antagonists may also be used in combination with ACEIs, as some studies have shown cumulative benefits for the combination. In addition to being used in Stage IV HF patients, in whom it has a marked benefit, spironolactone should be studied in less severe HF and in the presence of beta-blockers. The use of carvedilol, extended-release metoprolol and bisoprolol should be extended to severe HF patients as these agents have been shown to decrease mortality in this group. The ancillary properties of carvedilol, particularly antagonism at prejunctional beta -adrenoceptors, may give it additional benefits to selective beta(1)-adrenoceptor antagonists. Celiprolol and bucindolol are not the beta-blockers of choice in HF, as they do not decrease mortality. Although digitalis does not reduce mortality, it remains the only option for a long-term positive inotropic effect, as the long-term use of the phosphodiesterase inhibitors is associated with increased mortality. The calcium sensitising drug levosimendan may be useful in the hospital treatment of decompensated HF to increase cardiac output and improve dyspnoea and fatigue. The antiarrhythmic drug amiodarone should probably be used in patients at high risk of arrhythmic or sudden death, although this treatment may soon be superseded by the more expensive implanted cardioverter defibrillators, which are probably more effective and have fewer side effects. The natriuretic peptide nesiritide has recently been introduced for the hospital treatment of decompensated HF. Novel drugs that may be beneficial in the treatment of HF include the vasopeptidase inhibitors and the selective endothelin-A receptor antagonists but these require much more investigation. However, disappointing results have been obtained in a large clinical trial of the tumour necrosis factor alpha antagonist etanercept, where no likelihood of a difference between placebo and etanercept was observed. Small clinical trials with recombinant growth hormone to thicken ventricles in dilated cardiomyopathy have given variable results.

Risk-benefit assessment of angiotensin II receptor antagonists

Inhibiting the renin-angiotensin-aldosterone system through the use of angiotensin-converting enzyme (ACE) inhibitors has proven very useful in the treatment of hypertension, congestive heart failure (CHF) and progressive renal failure. More recently, agents that directly block the angiotensin II Type 1 (AT(1)) receptor--angiotensin II receptor antagonists (AIIRAs)--have been developed. These agents are thought to have a more specific mechanism of action since they do not affect other hormone systems as do the ACE inhibitors. Whether such specificity results in a different efficacy profile is still being determined. However, these drugs are extremely well-tolerated and very safe. AIIRAs are effective in the reduction of both systolic and diastolic blood pressure and compare favourably to other classes of agents. Recent results indicate that at least one AIIRA has a favourable effect on stroke in hypertensive patients with left ventricular hypertrophy. Additional studies with other members of the class will provide further information on similar outcomes. In CHF patients, ACE inhibitors remain the drug of choice and AIIRAs are best utilised in patients who cannot tolerate an ACE inhibitor or in those receiving an ACE inhibitor who cannot tolerate a beta-blocker and need additional therapy. AIIRAs are effective in slowing the progression of renal failure in patients with Type II diabetes and may be effective in other proteinuric conditions. Whether they are more or less effective than ACE inhibitors is unknown. Overall, AIIRAs represent an important addition to the armamentarium of cardiovascular therapies with an excellent safety record and an emerging profile of utility in multiple cardiovascular conditions.

Candesartan cilexetil plus hydrochlorothiazide combination: a review of its use in hypertension

The combination of candesartan cilexetil [an angiotensin II type 1 (AT(1)) receptor antagonist] plus hydrochlorothiazide (a thiazide diuretic), has been used in the treatment of patients with hypertension. The blood pressure (BP) lowering effect of various doses of this combination, administered orally once a day for 4 to 52 weeks, has been demonstrated in clinical trials. These studies showed that combinations of candesartan cilexetil 4 to 16 mg with hydrochlorothiazide 12.5 or 25 mg induced significant reductions reductions in systolic (S) BP and diastolic (D) BP from baseline in patients with mild to severe hypertension. Data from clinical trials indicated that reductions in BP induced by candesartan cilexetil 4 to 32 mg/hydrochlorothiazide 12.5 mg combinations were significantly greater than those observed after monotherapy with either drug. Treatment for 8 weeks with candesartan cilexetil 16 mg/hydrochlorothiazide 12.5 mg or candesartan cilexetil 16 mg induced SBP/DBP reductions of 12.0/7.5 mm Hg and 7.5/5.5mm Hg, respectively (p < 0.05 both comparisons). Moreover, data from a randomised, double-blind, placebo-controlled, dose-finding study in 1038 patients with mild to moderate hypertension showed that the greatest reductions in SBP/DBP were achieved by candesartan cilexetil 16 mg/hydrochlorothiazide 12.5 mg. Significant differences in BP reduction in favour of the combination were observed when hypertensive patients were given candesartan cilexetil 4 or 8 mg/hydrochlorothiazide 12.5 mg or hydrochlorothiazide monotherapy for 8 weeks. Additionally, greater efficacy of the combination compared to monotherapy with either drug was demonstrated by response rates to treatment. Moreover, a fixed combination of candesartan cilexetil 16 mg/hydrochlorothiazide 12.5 mg demonstrated a greater antihypertensive effect than losartan 50 mg/hydrochlorothiazide 12.5 mg in two clinical trials. Candesartan cilexetil 8 mg/hydrochlorothiazide 12.5 mg showed a similar antihypertensive effect compared with that of combined lisinopril 10 mg/hydrochlorothiazide 12.5 mg. Candesartan cilexetil/hydrochlorothiazide combination was well tolerated in patients with hypertension. Combined data from placebo-controlled trials showed that most adverse events were uncommon and not serious. Patients receiving combination therapy exhibited, among other adverse events, headache (3.2 vs 5.5% for candesartan cilexetil/hydrochlorothiazide and placebo, respectively), back pain (3.0 vs 2.4%), dizziness (2.6 vs 1.2%) and respiratory infection (2.5 vs 1.4%). Moreover, 3.3 and 2.7% of patients receiving candesartan cilexetil/hydrochlorothiazide or placebo, respectively, discontinued treatment because of adverse events.

CONCLUSION

The combination of candesartan cilexetil and hydrochlorothiazide (AT(1)-receptor antagonist and thiazide diuretic, respectively) is an effective treatment for patients with hypertension. Data from randomised, double-blind, placebo-controlled clinical trials showed that this combination is significantly more efficacious than either agent alone. Moreover, the combination of these two agents showed an excellent adverse event profile. Current data support the use of this combination as an alternative when monotherapy with either agent is not effective, and there are no compelling or specific indications for other drugs. However, data from large clinical trials, evaluating morbidity and mortality outcomes, are needed to determine the precise role of candesartan cilexetil/hydrochlorothiazide combination in the treatment of patients with hypertension.

The practical aspects of combination therapy with angiotensin receptor blockers and angiotensin-converting enzyme inhibitors

Angiotensin-converting enzyme (ACE) inhibitors and/or angiotensin receptor blockers (ARBs) are widely prescribed for the management of hypertension. ACE inhibitors (ACE-I) and, more recently, ARBs have an established track record of success in the treatment of congestive heart failure (CHF), proteinuric renal disease and most recently the hypertensive patient with a high cardiac-risk profile. The individual success of each of these drug classes has fuelled speculation that given together the overall effect of both would exceed that of either given alone. This premise, although biologically plausible, has yet to be proven in a convincing enough fashion to support the routine use of these two drug classes in combination. Additional clarifying studies are needed to establish whether specific patient subsets exist that might benefit from such combination therapy.

Renin-angiotensin system antagonism and lipid-lowering therapy in cardiovascular risk management

The renin-angiotensin system (RAS) and dyslipidaemia have been shown to be involved in the genesis and progression of atherosclerosis. Manipulation of the RAS has been effective in modifying human coronary artery disease progression. Similarly, the 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase inhibitors or statins have been shown to reduce cholesterol and lower cardiovascular events in primary and secondary prevention trials in coronary artery disease. In addition to their primary mode of action, statins and blockers of the RAS possess common additional properties that include restoration of endothelial activity and inhibition of cellular proliferation. This article reviews the current data on the common properties of these classes of drugs in which the beneficial effects extend beyond their antihypertensive and lipid-lowering properties.

Statins and chronic heart failure: do we need a large-scale outcome trial?

Hydroxymethylglutaryl-coenzyme A reductase inhibitors (statins) are of proven clinical benefit in coronary heart disease, at least in those patients who do not have overt chronic heart failure (CHF). However, as there have been no prospective clinical trials of statins in CHF patients, the question arises as to whether the benefits observed in the absence of CHF can be necessarily inferred in those patients in whom CHF is established. In this review, the evidence base stating support of the use of statins in CHF is presented, as well as theoretical considerations as to why these agents may not necessarily be of benefit in this setting. The beneficial potential of statins clearly relates to their plaque stabilization properties and associated improvements in endothelial function, which together should reduce the risk of further infarction and, perhaps, the ischemic burden on the failing ventricle. Furthermore, these agents may have beneficial effects independent of lipid lowering. These include actions on neoangiogenesis, downregulation of AT(1) receptors, inhibition of proinflammatory cytokine activity and favorable modulation of the autonomic nervous system. The potential adverse effects of statins in CHF include reduction in levels of coenzyme Q10 (which may further exacerbate oxidative stress in CHF) and loss of the protection that lipoproteins may provide through binding and detoxifying endotoxins entering the circulation via the gut. In support of these possibilities are epidemiologic data linking a lower serum cholesterol with a poorer prognosis in CHF. These uncertainties indicate the need for a definitive outcome trial to assess the efficacy and safety of statins in CHF, despite their current widespread, non-evidence based use in this population.

Angiotensin II Type 1 receptor antagonists in chronic heart failure

Angiotensin II Type 1 receptor antagonists share most but not all of their pharmacological actions with angiotensin-converting enzyme inhibitors. The latter belong to standard heart failure therapy, with proven benefit in terms of morbidity and mortality. Promising data have been provided for angiotensin II Type 1 receptor antagonists in experimental models of heart failure. In patients with hypertension and those with diabetic nephropathy, favourable results have been observed with regards to blood pressure control, reversibility of structural changes or prevention of progression of disease. The currently available clinical trials in heart failure patients with angiotensin II Type 1 receptor antagonists suggest that they may be equivalent to angiotensin-converting enzyme inhibitors, but superiority has not been proven. There is no doubt about their effectiveness with regards to symptoms; however, their effect on hospitalisation and mortality is not unequivocally demonstrated. Further trials are warranted, particularly to define their role in comparison with and in addition to angiotensin-converting enzyme inhibitors and to further characterise heart failure patient populations who derive benefit from angiotensin II Type 1 receptor blockers above and beyond angiotensin-converting enzyme inhibitors, beta-blockers and spironolactone.

BNP in hormone-guided treatment of heart failure

The pharmacotherapy of heart failure has become complex. Angiotensin-converting enzyme inhibitors (or angiotensin II receptor blockers), beta-blockers, spironolactone, diuretics and digoxin can be prescribed concurrently. Endothelin antagonists and combined inhibitors of converting enzyme and neutral endopeptidase are under investigation. Optimal dosing will become increasingly difficult to judge. Plasma brain natriuretic peptide (BNP) indicates the severity of left ventricular dysfunction. The C-terminal bioactive peptide and N-terminal BNP (N-BNP) circulate at concentrations related to cardiac status. We proposed that plasma levels of N-BNP would provide an index to guide drug treatment in established heart failure. Sixty-nine patients were randomized to treatment adjusted according to clinical criteria or plasma N-BNP. Hormone-guided therapy resulted in fewer clinical end points than did clinical management. This encourages further exploration of hormone guidance of anti-heart failure therapy, which could be extended to patients with preserved ejection fraction, in addition to those with established systolic dysfunction.

Is heart failure with preserved systolic function an overlooked enigma?

Heart failure with preserved systolic function, or diastolic heart failure, represents the neglected other half of the pandemic of heart failure. Unlike previously held beliefs, diastolic heart failure carries with it the same connotation of morbidity and mortality as systolic heart failure, particularly in the elderly. Due to lack of standards in application of the diagnosis of diastolic heart failure, studies are difficult to interpret due to heterogeneity in the clinical criteria applied to the patient enrollment. It is imperative that preventive efforts be implemented in high-risk groups, and screening measures with newer biomarkers be considered for identifying underlying structural heart disease in order to employ preventive therapy early in the course of illness. No evidence-based therapeutic strategy to reduce morbidity and mortality has been established, even after the diagnosis of diastolic heart failure is manifest. Current therapy targets lusitropic abnormalities in the realm of impaired relaxation, abnormal diastolic compliance, avoidance of tachycardia, and restoration of atrial booster pump function. Outcomes-based placebo-controlled clinical trials are currently underway to define appropriate therapeutic strategies in diastolic heart failure.

The Evolving Role of Angiotensin Receptor Blockers in Heart Failure

This continuing feature will update readers on recent developments in cardiovascular pharmacotherapy. Cardiovascular disease remains the number one killer in the US, and more clinical outcome trials have been conducted in cardiology than in any other field of medicine. Given this rapidly expanding knowledge base, pharmacists can have a significant impact on the prevention and treatment of cardiovascular disease—if they keep current with developments in drug therapy.

Clinical pharmacokinetics of candesartan

Candesartan cilexetil is the prodrug of candesartan, an angiotensin II type 1 (AT1) receptor antagonist. Absorbed candesartan cilexetil is completely metabolised to candesartan. Oral bioavailability is low (about 40%) because of incomplete absorption. Plasma protein binding in humans is more than 99%. The volume of distribution in healthy individuals is 0.13 L/kg. CV-15959 is the inactive metabolite of candesartan. Candesartan that reaches the systemic circulation is mainly cleared by the kidneys, and to a smaller extent by the biliary or intestinal route. The apparent oral clearance of candesartan is 0.25 L/h/kg after a single dose in healthy individuals. Oral clearance (3.4 to 28.4 L/h) is highly variable among patients. No relevant pharmacokinetic drug-food or drug-drug interactions are known. The terminal elimination half-life remains unclear, but appears to be longer than the currently used range of 4 to 9 hours. Non-compartmental models do not appear to be appropriate for the analysis of candesartan pharmacokinetic data. A 2-compartment analysis revealed a much longer half-life of 29 hours using data from patients with hypertension. However, a further indepth analysis has never been performed. The concentration-effect relationship is unaffected by age. No gender or race differences have been shown in the effect or pharmacokinetics of candesartan. Renal function affects the pharmacokinetic profile of candesartan. For patients with creatinine clearances of >60 ml/min x 1.73m(2), 30 to 60 ml/min x 1.73m(2) and 15 to 30 ml/min x 1.73m(2), the elimination half-life is 7.1, 10.0 and 15.7 hours, respectively, at a dose of 8 mg/day. However, at 12 mg/day an accumulation factor of 1.71 was found. Thus, a maximum daily dose of up to 8mg appears suitable in patients with severe renal dysfunction. No significant elimination of candesartan occurs with haemodialysis. In patients with mild to moderate hepatic impairment, no relevant pharmacokinetic alterations have been observed. Dosages of up to 12 mg/day do not require precautions in patients with mild to moderate liver disease. Clinically effective dosages range between 8 and 32 mg/day. The response rate of monotherapy with candesartan in patients with hypertension increases with dosage, but never exceeds 60% at a daily dosage of 16mg of candesartan. Dosages up to 32 mg/day do not increase this response rate.

Comment--Val-HeFT and angiotensin-receptor blockers in perspective: A tale of the blind man and the elephant

BACKGROUND

The role of angiotensin-receptor blockers (ARBs) in the therapy of chronic heart failure (CHF) has not been clarified. There are no large placebo-controlled trials with these agents. The second Evaluation of Losartan in the Elderly trial (ELITE-II) compared the ARB losartan with captopril in 3,152 patients >/=60 years old with New York Heart Association (NYHA) class II-IV and left ventricular ejection fraction </=40% and did not establish the efficacy of the ARB or its equivalent to angiotensin-converting enzyme inhibitor. The Valsartan Heart Failure Trial was designed to determine whether addition of valsartan improved the outcomes of patients receiving standard therapy for heart failure, which in most cases included an ACE inhibitor.

METHODS AND RESULTS

A total of 5,010 patients with NYHA class II-IV CHF and ejection fraction <40% were assigned to receive 160 mg valsartan or placebo twice daily. The 2 coprimary end points were all-cause mortality and the composite of mortality and morbidity, defined as the incidence of hospitalization for heart failure, resuscitated sudden death, or receipt of intravenous inotropic or vasodilator therapy for at least 4 hours (with hospitalizations accounting for 94% of the nonfatal end points). Mortality was similar in the 2 groups, but the combined mortality and morbidity end point was 13.2% lower with valsartan (relative risk, 0.87; 95% confidence interval, 0.77-0.97; P.009), primarily because of a reduction in the number of patients hospitalized for CHF (13.8% v 18.2%). There were improvements in several secondary end points, including ejection fraction, signs and symptoms of CHF, and quality of life with valsartan. Of note is that analyses of subgroups defined according to background therapy at baseline showed highly significant interactions. For instance, the small subgroup of 366 patients (7%) who were not receiving ACE inhibitors had a 33% reduction in mortality and a 44% decrease in mortality and morbidity, whereas the morbidity and mortality benefit of valsartan observed in the overall trial was no longer significant in patients receiving background ACE inhibitor therapy (relative risk, 0.90; P.10). The larger subgroup of patients receiving both an ACE inhibitor and a beta-blocker at baseline had a statistically significant 42% increase in mortality with valsartan (P.009) and a trend toward an increase in the mortality and morbidity composite (P.10).

CONCLUSIONS

When added to standard therapy, valsartan has no overall effect on mortality and produces a modest (13.2%) reduction in morbidity and mortality. However, this benefit is much larger in patients not receiving concomitant ACE inhibitor therapy and statistically not significant in those who are taking ACE inhibitors. Somewhat troublesome is the finding of significant increase in mortality with valsartan in patients receiving both ACE inhibitor and beta-blocker therapy.

Efficacy of angiotensin II type 1 receptor blockade on reperfusion-induced arrhythmias and mortality early after myocardial infarction is increased in transgenic rats with cardiac angiotensin II type 1 overexpression

Angiotensin II induces ischemia/reperfusion (I/R)-induced arrhythmias and blockade of the angiotensin II type 1 receptor (AT1R) may therefore be beneficial in preventing arrhythmias and decreasing mortality after myocardial infarction (MI). Because the AT1R is upregulated after myocardial ischemia, it was hypothesized that the level of AT1R expression would mediate the response to AT1R blockade. Transgenic (TGR) rats that overexpress the human AT1R and Sprague-Dawley rats were used as controls. Total duration of arrhythmia (seconds) after I/R injury was similar in TGR and SD rats (433 +/- 109 vs. 376 +/- 117, p = n.s.). AT1R blockade with losartan decreased total duration of arrhythmia in the TGR rats (433 +/- 110 s-164 +/- 48 s; p < 0.05), whereas it caused a nonsignificant increase in the SD rats (376 +/- 117 s-497 +/- 97). In vivo, survival in the first 24 hours after MI was impaired in TGR rats (39%; SD, 63%). Losartan improved survival significantly in TGR rats (from 39% to 80%, p < 0.05). A smaller, nonsignificant effect was observed in SD rats (63% to 81%). AT1R blockade is beneficial only when the AT1R was overexpressed, both in reducing the reperfusion-induced arrhythmias and mortality early after MI.

Addition of candesartan to angiotensin converting enzyme inhibitor therapy in patients with chronic heart failure does not reduce levels of oxidative stress

BACKGROUND

Angiotensin II exerts a number of harmful effects in patients with chronic heart failure (CHF) and, through an increase in oxidative stress, is thought to be critical in the development of endothelial dysfunction. Angiotensin II may be elevated in CHF despite treatment with angiotensin converting enzyme (ACE) inhibitors, producing a rationale for adjunctive angiotensin receptor blockade. We investigated whether the addition of angiotensin antagonism to ACE inhibition would reduce oxidative stress and improve endothelial function and exercise tolerance in patients with chronic heart failure.

METHODS AND RESULTS

Twenty-eight heart failure patients, who were on stable ACE inhibitor therapy, were randomised to receive adjunctive therapy with candesartan or placebo. Plasma lipid-derived free radicals, TBARS and neutrophil O2-generation, markers of oxidative stress, were measured in venous blood. Arterial endothelial function was assessed as the response of the brachial artery to flow-related shear stress. Exercise capacity was determined by cardiopulmonary exercise testing. Compared with placebo, candesartan had no effect on changes in lipid derived free radicals (-0.1+/-1.2 vs. -0.1+/-1.0 units, respectively, P=NS), TBARS (-2.2+/-1.1 vs. -2.6+/-2.2 micromol/l, respectively, P=NS) or neutrophil O2-generating capacity (-7.3+/-5.1 vs. -8.4+/-7.9 mV/5x10(5) neutrophils, respectively, P=NS). There was no effect on changes in brachial artery flow-mediated dilatation (0.5+/-1.0 vs. 0.8+/-1.3%, respectively, P=NS) nor peak VO2 (1.6+/-0.7 ml/kg per min vs. 1.8+/-0.6 ml/kg per min; P=NS).

CONCLUSION

The addition of the candesartan to ACE inhibitor therapy had no effect on oxidative stress and did not improve endothelial function or exercise capacity in patients with CHF.

Angiotensin receptor blockers in heart failure: meta-analysis of randomized controlled trials

OBJECTIVES

We sought to determine the effect of angiotensin receptor blockers (ARBs) on mortality and hospitalization in patients with heart failure (HF).

BACKGROUND

There is uncertainty regarding the efficacy of ARBs as substitute or adjunctive therapy to angiotensin-converting enzyme inhibitors (ACEIs) in the treatment of HF.

METHODS

We conducted a meta-analysis of all randomized controlled trials that compared ARBs with either placebo or ACEIs in patients with symptomatic HF. The pooled outcomes were all-cause mortality and hospitalization for HF.

RESULTS

Seventeen trials involving 12,469 patients were included. Overall, ARBs were not superior to controls in the pooled rates of death (odds ratio: 0.96; 95% confidence interval: 0.75 to 1.23) or hospitalization (0.86; 0.69 to 1.06). Stratified analysis, however, showed a non-significant trend in benefit of ARBs over placebo in reducing mortality (0.68; 0.38 to 1.22) and hospitalization (0.67; 0.29 to 1.51) when given in the absence of background ACEI therapy. When compared directly with ACEIs, ARBs were not superior in reducing either mortality (1.09; 0.92 to 1.29) or hospitalization (0.95; 0.80 to 1.13). In contrast, the combination therapy of ARBs and ACEIs was superior to ACEIs alone in reducing hospitalization (0.74; 0.64 to 0.86) but not mortality (1.04; 0.91 to 1.20).

CONCLUSIONS

This meta-analysis cannot confirm that ARBs are superior in reducing all-cause mortality or HF hospitalization in patients with symptomatic HF, particularly when compared with ACEIs. However, the use of ARBs as monotherapy in the absence of ACEIs or as combination therapy with ACEIs appears promising.

Recent advances in the treatment of heart failure

Treatment strategies for patients with heart failure and left ventricular systolic dysfunction continue to evolve as the complex pathophysiology of this disease is better understood. A number of advances have been made in recent years, most notably the addition of beta-receptor antagonists. In addition, recent studies have provided important information regarding the utility of angiotensin receptor antagonists, aldosterone receptor antagonists, and natriuretic peptides in the management of heart failure. Nonpharmacologic advances include resynchronization therapy, which appears to confer symptomatic improvement in some patients, and improvements in ventricular assist device technology. As the importance of neurohormonal activation in the progression of heart failure becomes increasingly apparent, new therapeutic strategies targeting these neurohormonal systems are being investigated.

Diastolic heart failure: neglected or misdiagnosed?

Recent epidemiological studies suggest that 30% to 50% of patients with heart failure (HF) have preserved left ventricular (LV) systolic function. These patients, often presumed to have diastolic heart failure (DHF), appear to have lower short-term but similar long-term mortality when compared to patients with HF and LV systolic dysfunction. Rates of recurrent hospitalization and costs of care appear similar in the two groups of patients. Therefore, DHF may contribute significantly to the burden of disease caused by HF. Exertional breathlessness, the principal symptom of HF, has many causes, including obesity, pulmonary disease and myocardial ischemia. A diagnosis of DHF by exclusion, based on symptoms in the absence of important LV systolic dysfunction or major valve disease, is unsatisfactory. Unfortunately, as yet, no reliable definition with which to make a positive diagnosis of DHF has been agreed on, frequently rendering this diagnosis uncertain. Echocardiography has several limitations, whereas hemodynamic confirmation of DHF by cardiac catheterization is potentially complex and not practically feasible for many patients. Treatment of DHF remains empirical and unsatisfactory because of the lack of large-scale randomized controlled trials in this area. Currently, three large outcome studies on DHF are in progress along with other smaller trials. These should start to provide some of the answers we need to diagnose and effectively treat DHF.