Electrophysiologic profile of ibopamine in patients with congestive heart failure and ventricular tachycardia and relation to its effects on hemodynamics and plasma catecholamines

Prognostic value of heart rate variability and ventricular arrhythmias during 13-year follow-up in patients with mild to moderate heart failure

BACKGROUND

In contrast to patients with moderate to severe chronic heart failure (CHF), data regarding long-term outcome in patients with mild CHF are scarce. We examined the place of Holter monitoring to study the prognostic value of ventricular arrhythmias and heart rate variability (HRV) in patients with mild to moderate CHF during long-term follow-up.

METHODS

We studied 90 patients with mild to moderate CHF and NYHA class II who had been enrolled in the Dutch Ibopamine Multicenter Trial. At baseline their mean age was 60.5 +/- 8.0 years, left ventricular ejection fraction (LVEF) was 0.29 +/- 0.09, and 85% were males. At the start of the study, patients were only using diuretics, while digoxin, and particularly ACE inhibitors and beta-blockers were initiated later. Univariate and multivariate proportional hazard analyses were performed.

RESULTS

At baseline 80% of patients were in NYHA class II, and 20% were in class III; their mean age was 60 years, mean LVEF was 0.29, and 85% were men. During a follow-up of 13 years, 47 patients (53%) died. Cardiovascular (CV) death occurred in 39 patients, of which 28 were sudden cardiac death (SCD). For both CV death and SCD, LVEF <30% and ventricular premature beats/h (>20) were independent risk markers. Of the HRV parameters, total power (>2,500 ms(2)) was an important risk marker for CV death, but not for SCD.

CONCLUSION

The present 13-year follow-up study in 90 patients with mild to moderate CHF showed that ventricular premature beats and HRV may have important value in predicting outcome.

Clinical characteristics of patients with increased urinary excretion of adrenaline in mild to moderate heart failure

BACKGROUND

We have previously demonstrated that adrenaline (AD) is released into the circulation during acute myocardial infarction and is associated with a more severe clinical course. The role of elevated AD levels in congestive heart failure is not known.

HYPOTHESIS

The study aimed to determine whether increased daily AD excretion is associated with more severe clinical symptoms and a more complicated clinical course in patients with exacerbation of congestive heart failure (CHF).

METHODS

Urinary excretion of AD, noradrenaline, magnesium (Mg), and potassium (K), serum levels of aldosterone, K, and Mg, as well as the incidence of arrhythmias (24-h Holter) were assessed in 49 patients with CHF New York Heart Association (NYHA) class II-III. The patients were allocated to two groups, with normal (Group 1) and increased (Group 2) excretion of AD.

RESULTS

Groups 1 and 2 did not differ in respect of age, etiology of CHF, or the medication used. Also, left ventricular ejection fraction was similar in the two groups. However, left ventricular end-diastolic dimension was greater in Group 2 (61+/-9 vs. 55+/-11 mm, p<0.05), as was the proportion of patients in NYHA class III (74 vs. 40%). Group 2 was also characterized by increased urinary excretion of Mg (60+/-24 vs. 43+/-16 mg/24 h, p < 0.007) and the presence of more complex and numerous ventricular arrhythmias (74 vs. 37% and 68 vs. 33% of patients, respectively).

CONCLUSIONS

Urinary excretion of AD is increased only in a subgroup of patients with CHF. These patients are characterized by a more advanced NYHA class, increased end-diastolic left ventricular diameter, and increased urinary excretion of magnesium. It is likely that all these factors contribute to the presence of more complex and numerous ventricular arrhythmias in this subgroup of patients.

Randomised study of effect of ibopamine on survival in patients with advanced severe heart failure. Second Prospective Randomised Study of Ibopamine on Mortality and Efficacy (PRIME II) Investigators

BACKGROUND

Drugs that improve symptoms in patients with heart failure must also be assessed for their effects on survival. Ibopamine stimulates DA-1 and DA-2 receptors and causes peripheral and renal vasodilatation; the drug improves symptoms of heart failure. We assessed the effect of ibopamine on survival in patients with advanced heart failure in a multicentre, randomised placebo-controlled study.

METHODS

Patients with advanced severe heart failure (New York Heart Association classes III and IV) and evidence of severe left-ventricular disease, who were already receiving optimum treatment for heart failure, were randomly allocated oral ibopamine 100 mg three times daily or placebo. The primary endpoint was all-cause mortality. The study was designed to recruit 2200 patients, and the minimum duration of treatment would be 6 months. We did intention-to-treat and on-treatment analyses; a post-hoc subgroup analysis was also done.

FINDINGS

After we had recruited 1906 patients the trial was stopped early, because of an excess of deaths among patients in the ibopamine group. 232 (25%) of 953 patients in the ibopamine group died, compared with 193 (20%) of 953 patients in the placebo group (relative risk 1.26 [95% CI 1.04-1.53], p = 0.017). The average length of follow-up was 347 days in the ibopamine group and 363 days in the placebo group. In multivariate analysis, only the use of antiarrhythmic drugs at baseline was a significant independent predictor of increased fatality in ibopamine-treated patients.

INTERPRETATION

Ibopamine seems to increase the risk of death among patients with advanced heart failure who are already receiving optimum therapy, but the reasons for this increase are not clear. Our finding that antiarrhythmic treatment was a significant predictor of increased mortality in ibopamine-treated patients may be important, but exploratory analyses must be interpreted with caution.

Current and newer approaches in the drug treatment of congestive heart failure

Most patients with chronic congestive heart failure (CHF) are subjected to symptomatic treatment, predominantly with drugs. Over the years, it has become clear that treatment with unloading drugs is probably more beneficial than treatment with inotropic agents. In addition, it has been widely recognized that the neuroendocrine compensatory changes associated with CHF afford and important target for drug treatment. This may also hold for some of the changes in receptor density, such as the downregulation of cardiac beta-adrenoceptors. The present and clearly changing insights into the backgrounds of drugs for the treatment of CHF are critically discussed. Apart from the changing views and appreciation of the currently used drugs (diuretics, ACE inhibitors, digoxin, beta-adrenoceptor agonists), the following new approaches are discussed: beta-blockers, angiotensin II receptor antagonists, ibopamine, calcium antagonists, inhibitors of ANP degradation, vasopression antagonist, vesnarinone, and calcium sensitizers.

Clinical and autonomic effects of ibopamine as adjunct to angiotensin-converting enzyme inhibitors in chronic heart failure

BACKGROUND

The purpose of this study was to determine the additive value of ibopamine in heart failure patients who are treated with angiotensin-converting enzyme inhibitors. Ibopamine exerts hemodynamic and neurohumoral effects, and is beneficial in mild heart failure; however, its additive value in more advanced disease in unclear.

METHODS AND RESULTS

The study was a stand-alone, double-blind, randomized parallel group comparison of ibopamine (100 mg 3 times daily) and placebo in 59 patients with New York Heart Association functional class III-IV heart failure. Patients were clinically stable on drug treatment, including an angiotensin-converting enzyme inhibitor, and they were randomized to ibopamine (n = 29) or placebo (n = 30). Assessments were performed at baseline and after 3 months of treatment, and included measurement of peak oxygen consumption, plasma neurohormones, ambulatory arrhythmias, and heart rate variability. At baseline, the two groups were well matched, including age (mean, 63 years), left ventricular ejection fraction (0.23), and peak oxygen consumption (15.4 mL/min/kg). After 3 months, four patients had dropped out of the study because of progressive heart failure (ibopamine, n = 1; placebo, n = 3; not significant) and two because of side effects (n = 1/1). Exercise time and peak oxygen consumption were not significantly affected (exercise time: ibopamine, +54 [95% confidence interval, -12, 120] seconds; placebo, +19 [-42, 81] seconds; peak oxygen consumption: ibopamine, +0.3 [-0.5, 1,2] mL/min/kg; placebo, +0.2 [-0.7, 1.0] mL/min/kg). Plasma neurohormones and ventricular arrhythmias during ambulatory monitoring were also unaffected. In contrast, heart rate variability parameters, in particular those associated with vagal tone (rMMSD, high-frequency power), significantly increased after 3 months on ibopamine (P = .01 vs placebo).

CONCLUSIONS

In this group of patients with clinically stable moderate to severe chronic heart failure, only a marginal and statistically nonsignificant effect on clinical parameters was observed after 3 months of treatment with ibopamine. Heart rate variability parameters, however, were significantly affected by ibopamine, despite the absence of an effect on plasma neurohormones.

Clinical efficacy of ibopamine in patients with chronic heart failure

Ibopamine, the most widely studied dopaminergic drug for the treatment of chronic heart failure, appears to have beneficial hemodynamic, renal, and neurohormonal effects in this setting. Angiotension-converting enzyme (ACE) inhibitors have become the recommended standard treatment for chronic heart failure; however, some patients may benefit from additional drugs to improve their symptoms and functional capacity. Ibopamine may be effective as an additive drug for patients with chronic heart failure. It is also possible that ibopamine will improve survival in these patients. Large-scale trials are needed to assess the effects on morbidity and mortality when ibopamine is added to ACE inhibitors, diuretics, and possibly digitalis.

Pharmacotherapy of congestive heart failure. Currently used and experimental drugs

A survey is given of the currently used therapeutics in the treatment of chronic congestive heart failure. Symptomatic treatment is usually performed along the following lines: rest, sodium and fluid restriction to unload the decompensating heart, loop diuretics, angiotensin-converting enzyme inhibitors or other vasodilators; inotropic agents to improve the heart's mechanical performance; attempts to counteract the neuro-endocrine compensatory mechanisms, that is the activated sympathetic nervous and renin-angiotensin-aldosterone systems, as well as the rise in vasopressine levels. New insights have been obtained in the effects of cardiac glycosides, which are probably rather based on counteracting the elevated sympathetic neuronal activity than on their weak and uncertain inotropic action. Angiotensin-converting enzyme inhibitors are probably more effective than classical vasodilators owing to their additional interaction with the neuro-endocrine compensatory mechanisms. Ibopamine, a prodrug of epinine, appears to be rather a vasodilator and antagonist of the neuro-endocrine compensatory mechanisms than an inotropic agent. The most important clinical trials addressing the efficacy and adverse reactions to the various aforementioned therapeutics are discussed. New, experimental approaches in the drug treatment of chronic congestive heart failure include beta-blockers, calcium antagonists, vasopressin antagonists and inhibitors of atrial natriuretic peptide degradation.

Acute effect of ibopamine and isosorbide mononitrate on blood volume distribution in congestive heart failure

In order to compare ibopamine (IBO), a dopamine congener, with isosorbide mononitrate (ISMN) and to study their interaction in effects on the capacitance vasculature in congestive heart failure (CHF), a prospective, randomized, placebo-controlled, double-blind clinical trial was performed in 32 patients with New York Heart Association class II-IV CHF, randomly assigned to receive single oral doses of placebo, 200 mg IBO, 20 mg ISMN, or both IBO and ISMN. After labelling of red cells with 99mTc, changes in regional radioactivity, indicative of changes in blood volume, were recorded using a gamma-camera before and at 30, 60 and 120 min after drug administration. At 30 and 60 min, arterial systolic and pulse pressures were higher with IBO than with ISMN and placebo (for pulse pressure by mean 13.7 mmHg, 95% confidence interval 4.5-23.0 mmHg, at 30 min), probably reflecting an IBO-induced rise in stroke volume at unchanged heart rate and mean arterial pressure. IBO did not change regional radioactivity except for a transient increase of 4.4% (0.5-7.6%) in the thorax at 30 min. This was attenuated by concomitant ISMN treatment since, starting at 30 min, the drug increased radioactivity in the legs, compared with patients not receiving the drug, by 8.0% (95% confidence interval 0.2-15.8%), leading to a fall in thoracic and left ventricular radioactivity at 30 min of 3.4% (0.3-7.0%) and 6.4% (0.8-11.9%), respectively, and a fall of 5.5% (0.5-10.5%) in hepatic radioactivity at 60 min.(ABSTRACT TRUNCATED AT 250 WORDS)

Neurohumoral and hemodynamic effects of ibopamine in a rat model of chronic myocardial infarction and heart failure

There is increasing evidence that both neurohumoral and hemodynamic factors play a role in disease progression in chronic heart failure (CHF). To examine the influence of the oral dopamine agonist ibopamine on these factors, we studied 20 rats with chronic myocardial infarction and CHF, and compared them with 20 normal rats. After 6 weeks, rats were randomly divided between control treatment (50%) or ibopamine (50%) for 3 weeks. At the end of the study, plasma and tissue neurohumoral parameters, as well as hemodynamics, were determined. In infarcted rats, the elevated plasma norepinephrine (PNE) levels were reduced by ibopamine (251 +/- 19 vs. 138 +/- 32 pg/ml; p < 0.05). Other plasma neurohormones measured (epinephrine, renin, aldosterone, and angiotensin converting enzyme [ACE]) were not significantly increased in rats with myocardial infarction and were not affected by ibopamine. Cardiac (tissue) ACE was increased in infarcted rats (12.1 +/- 1.9 U/l/min) and was significantly lowered by ibopamine (9.6 +/- 1.0 U/l/min; p < 0.05); renal ACE was unaffected. Blood pressure and heart rate were similar in the two groups and were not influenced by ibopamine treatment. In conclusion, in chronic myocardial infarction and CHF in rats, ibopamine reduces the elevated levels of PNE and cardiac ACE. Further research will be needed to determine whether this effect may lead to a favorable influence on disease progression in CHF.

Double-blind placebo-controlled study of ibopamine and digoxin in patients with mild to moderate heart failure: results of the Dutch Ibopamine Multicenter Trial (DIMT)

OBJECTIVES

This study was conducted to determine the efficacy and safety of long-term treatment with the orally active dopamine agonist ibopamine in patients with mild to moderate chronic congestive heart failure and to compare the results with those of treatment with digoxin and placebo.

BACKGROUND

Ibopamine and digoxin are drugs that exert hemodynamic and neurohumoral effects. Because there is accumulating evidence that progression of disease in chronic heart failure is related not only to hemodynamic but also to neurohumoral factors, both drugs might be expected to have a favorable long-term effect.

METHODS

We studied 161 patients with mild to moderate chronic heart failure (80% in New York Heart Association functional class II and 20% in class III), who were treated with ibopamine (n = 53), digoxin (n = 55) or placebo (n = 53) for 6 months. Background therapy consisted of furosemide (0 to 80 mg); all other drugs for heart failure were excluded. Clinical assessments were made at baseline and after 1, 3 and 6 months.

RESULTS

Of the 161 patients, 128 (80%) completed the study. Compared with placebo, digoxin but not ibopamine significantly increased exercise time after 6 months (p = 0.008 by intention to treat analysis). Ibopamine was only effective in patients with relatively preserved left ventricular function, as it significantly increased exercise time in this subgroup (for patients with a left ventricular ejection fraction > 0.30; p = 0.018 vs. placebo). No patient receiving digoxin withdrew from the study because of progression of heart failure, compared with six patients receiving ibopamine and two receiving placebo. At 6 months, plasma norepinephrine was decreased with digoxin and ibopamine therapy (-106 and -13 pg/ml, respectively) but increased with placebo administration (+62 pg/ml) (both p < 0.05 vs. placebo). Plasma aldosterone was unaffected, but renin was decreased by both agents after 6 months (p < 0.05 vs. placebo). Total mortality and ambulatory arrhythmias were not significantly affected by the two drugs.

CONCLUSIONS

Ibopamine and digoxin both inhibit neurohumoral activation in patients with mild to moderate chronic heart failure. However, the clinical effects of these drugs are different and appear to be related to the degree of left ventricular dysfunction.

Ibopamine. A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic use in congestive heart failure

Ibopamine is an orally administered dopamine agonist which is rapidly converted to its active metabolite epinine by esterase hydrolysis. Ibopamine acts predominantly as a vasodilator and inhibitor of neuroendocrine activation in congestive heart failure, but also has mild positive inotropic effects at higher doses. The beneficial effects on cardiac and systemic haemodynamic parameters seen in short term studies have been maintained in predominantly noncomparative trials for up to 1 year, and improvements in New York Heart Association (NYHA) functional class and clinical symptoms have been observed in patients with congestive heart failure of varying severity. In double-blind studies conducted in small numbers of patients, the efficacy of ibopamine was comparable to that of digoxin, captopril, enalapril and hydrochlorothiazide. Ibopamine can successfully replace treatment with intravenous dopamine in patients with severe heart failure, and is effective and well tolerated when administered in combination with digoxin, diuretics and/or angiotensin converting enzyme (ACE) inhibitors. Ibopamine has shown no detrimental effects on renal function, few adverse effects on neurohormonal parameters and has demonstrated no significant proarrhythmic properties at therapeutic doses in patients with congestive heart failure. No adverse metabolic effects were observed during ibopamine therapy in patients with diabetes mellitus, nor did ibopamine have detrimental effects in patients with chronic obstructive pulmonary disease. While reliable evidence is required concerning effects on mortality before the role of ibopamine can be clearly defined, the drug appears to be a useful agent for combination with conventional therapies in treating patients with mild to severe congestive heart failure.

Effects of dopaminergic agents on cardiac and renal function in normal man and in patients with congestive heart failure

Dopamine is an effective drug in the management of acute congestive heart failure. Its beneficial action is due to both cardiovascular--peripheral vasodilation and positive inotropy--and renal effects. Dopexamine is one of the newer dopamine agonists. Like dopamine, however, it can only be administered intravenously, and its value in the chronic treatment of congestive heart failure is limited. For this reason, dopamine analogs were developed with oral bioavailability, including levodopa, fenoldopam and biopamine. Although both levodopa and fenoldopam have shown beneficial hemodynamic effects, these agents cannot be recommended for general use in patients with congestive heart failure. Levodopa frequently causes side effects, especially nausea, and fenoldopam induces an increase in neurohumoral activity, which limits its long-term efficacy. Ibopamine has vasodilatory, mild inotropic and diuretic properties and it lowers plasma norepinephrine levels. Since ibopamine is usually well tolerated, it appears to have the most interesting profile of these oral dopaminergic agents.

Effects of acute and chronic ibopamine administration on resting and exercise hemodynamics, plasma catecholamines and functional capacity of patients with chronic congestive heart failure

The effects of acute and chronic ibopamine treatment on resting and exercise hemodynamics, exercise capacity and plasma catecholamines were evaluated in 25 patients with chronic heart failure, using a double-blind, parallel, placebo-controlled design. During 2 months of therapy with either placebo or ibopamine (100 mg, 3 times daily), 1 patient was withdrawn from each group for worsening heart failure, New York Heart Association functional class improved in 4 patients on ibopamine and in 1 on placebo, and furosemide dose could be decreased in 4 on ibopamine and in no patient on placebo. Acute ibopamine administration induced, in comparison with placebo, a significant increase of cardiac and stroke volume indexes both at rest and peak exercise, with a reduction of systemic vascular resistance. These hemodynamic changes were maintained also after chronic therapy, with no evidence of tolerance development. Exercise capacity (evaluated as peak exercise duration and oxygen consumption, and ventilatory threshold) did not significantly change. Resting and peak exercise norepinephrine plasma levels were significantly reduced after both acute and chronic ibopamine administration. Thus, the hemodynamic and neurohumoral effects of ibopamine make this drug potentially useful for the chronic treatment of congestive heart failure.