Influence of short-term oral hydralazine therapy on exercise hemodynamics in patients with severe chronic heart failure

Hydralazine in chronic CHF

In summary, there investigations indicate that oral hydralazine produces beneficial hemodynamic effects in patients with chronic CHF. These favorable hemodynamic response are observed in the presence or absence of mechanical defects, such as mitral or aortic regurgitation. The predominant hemodynamic effects of hydralazine are substantial increase in CO and SV with decreased systemic vascular resistance. These investigations further suggest that hydralazine therapy not only improves resting cardiac performance, but also cardiac performance during exercise. There is also evidence that improved cardiac performance is sustained at least in some patients during maintenance hydralazine therapy. The impact of hydralazine therapy on the long term prognosis of patients with refractory CHF, however, remains unknown. Nevertheless, the preliminary retrospective studies suggest that in certain subsets of patients with severe chronic CHF, such therapy may provide a better prognosis compared to that expected with conventional therapy.

Splanchnic hyperemia after liver transplantation in patients with end-stage liver disease

Systemic and splanchnic hemodynamic parameters were evaluated in 12 patients with cirrhosis before and 3 and 6 months after liver transplantation. Results were compared with those obtained in 8 healthy subjects. Three months after liver transplantation recipients had an increase in mean arterial pressure (98 +/- 7 v 78 +/- 9 mmHg; P < .05), an insignificant decrease in cardiac index (3. 4 +/- 0.6 v 4.0 +/- 1.0 L . min-1 . m-2), and a marked increase in peripheral vascular resistance (1,563 +/- 308 v 800 +/- 205 dyne . s . cm-5; P < .05) compared with pretransplantation values. Portal blood flow was also significantly increased (1,494 +/- 200 v 829 +/- 130 mL/min; P < .05). These hemodynamic changes were more pronounced 6 months after transplantation (mean arterial pressure, 100 +/- 8 mmHg; cardiac index, 3.0 +/- 1.0 L . min-1 . m-2; P < .01; peripheral vascular resistance, 1,680 +/- 405 dyne . s . cm-5; portal blood flow, 1,520 +/- 180 mL/min). Systemic hemodynamics 6 months after liver transplantation were similar to those observed in the healthy control group (mean arterial pressure, 95 +/- 6 mmHg; cardiac index, 2.9 +/- 0.9 L . min-1 . m-2; peripheral vascular resistance, 1,480 +/- 380 dyne . s . cm-5). However, portal blood flow was still significantly higher than in healthy controls at 6 months (1,520 +/- 180 v 910 +/- 140 mL/min; P < .05). This study shows that systemic hemodynamics are normalized after liver transplantation. However, an increase in portal blood flow occurs and persists for at least 6 months after liver transplantation. Further studies are needed to clarify the cause of the abnormally high portal flows.

Prevention of tolerance to hemodynamic effects of nitrates with concomitant use of hydralazine in patients with chronic heart failure

OBJECTIVES

This study was designed to determine the effect of oral hydralazine on the development of nitrate tolerance in patients with chronic congestive heart failure.

BACKGROUND

Early development of nitrate tolerance with either continuous administration of intravenous or topical nitrate preparations or frequent dosing of oral nitrates leads to significant attenuation of nitrate-mediated hemodynamic and anti-ischemic effects. In recent animal experiments, prevention of nitroglycerin-induced hemodynamic tolerance with a concomitant use of hydralazine was demonstrated. This finding may have important clinical relevance.

METHODS

Twenty-eight patients with chronic heart failure due to left ventricular systolic dysfunction were randomized to receive either a continuous infusion (24 h) of nitroglycerin alone (group I, 14 patients) or concomitantly with oral hydralazine (75 mg four times a day [group II, 14 patients]). The effect of nitroglycerin in each group was evaluated by analysis of variance for repeated measures. The power of the analysis to detect a 5.4-mm Hg (20%) change in mean pulmonary artery wedge pressure was 90%.

RESULTS

Baseline hemodynamic variables as well as the initial hemodynamic response to nitroglycerin were comparable in both groups. Compared with the initial response to nitroglycerin, a significant attenuation of effect was found in group I at 24 h in mean (+/- SE) pulmonary artery pressure (27 +/- 4% vs. 10 +/- 3%, p < 0.05) and mean pulmonary artery wedge pressure (40 +/- 4% vs. 16 +/- 4%, p < 0.05). In group II, conversely, oral hydralazine prevented nitroglycerin-induced hemodynamic tolerance and resulted in a persistent effect on mean pulmonary artery and wedge pressures throughout the study period (31 +/- 3% vs. 27 +/- 4%, p = 0.13 and 37 +/- 4% vs. 34 +/- 6%, p = 0.40, respectively). In addition, the initial effect on blood pressure was attenuated at 24 h in group I (5 +/- 2% vs. 12 +/- 3%, p < 0.05) but not in group II (15 +/- 3% vs. 17 +/- 2%, p = 0.46).

CONCLUSIONS

In patients with chronic heart failure due to left ventricular systolic dysfunction, the concomitant use of oral hydralazine prevents early development of nitrate tolerance and results in a persistent nitrate-mediated hemodynamic effect on systemic and pulmonary artery and left ventricular filling pressures. These data may support the concurrent use of hydralazine in patients with heart failure treated with organic nitrates.

Acute effect of percutaneous transvenous mitral commissurotomy on ventilatory and hemodynamic responses to exercise. Pathophysiological basis for early symptomatic improvement

BACKGROUND

Improvement of exertional dyspnea occurs immediately after percutaneous transvenous mitral commissurotomy (PTMC), but the pathophysiological basis for this early symptomatic improvement has not been elucidated.

METHODS AND RESULTS

Exercise hemodynamic measurement and exercise ventilatory measurement with arterial blood gas analysis were performed in 21 patients aged 50.4 +/- 9.5 years (mean +/- SD) with symptomatic mitral stenosis before and a few days after PTMC. Exercise ventilatory measurement were also performed in 14 normal control subjects aged 48.9 +/- 4.9 years. After PTMC, mitral valve area increased (from 1.0 +/- 0.3 to 1.7 +/- 0.3 cm2, P < .001), mean mitral gradient (from 12.2 +/- 5.2 to 5.2 +/- 2.2 mm Hg, P < .001), and mean left atrial pressure (from 18.7 +/- 6.1 to 12.1 +/- 4.0 mm Hg, P < .001) decreased. All patients experienced significant symptomatic improvement soon after PTMC. Comparison of hemodynamic parameters at the same ergometer work rate showed a significant decrease in pulmonary artery systolic pressure (from 77 +/- 18 to 67 +/- 14 mm Hg, P < .001) and diastolic pressure (from 36 +/- 10 to 28 +/- 7 mm Hg, P < .001) and a significant increase in cardiac output (from 6.4 +/- 1.4 to 8.1 +/- 1.9 L/min, P < .001). Despite the improvement in exercise hemodynamics and symptoms, exercise capacity determined by peak oxygen uptake (from 18.0 +/- 2.9 to 18.6 +/- 3.1 mL.kg-1 x min-1) and anaerobic threshold (from 11.7 +/- 2.4 to 12.0 +/- 2.4 mL.kg-1 x min-1) remained unchanged. Excessive exercise ventilation, as assessed by the slope of the regression line between expired minute ventilation and carbon dioxide output, decreased significantly from 37.2 +/- 6.7 to 33.9 +/- 5.8 (P < .001), but remained significantly higher than that in the normal subjects (27.9 +/- 3.6, P < .01). The ratio of total dead space to tidal volume and total dead space per breath during exercise decreased significantly after PTMC (P < .05). The change in excessive exercise ventilation after PTMC was correlated with the change in dead space to tidal volume ratio (r = .59).

CONCLUSIONS

Significant relief of exertional dyspnea immediately after PTMC is not accompanied by an improvement in exercise capacity. A decrease in excessive ventilation due to a decrease in physiological dead space resulting from hemodynamic improvement partly contributes to the early relief of symptoms after PTMC. However, lung compliance, which was not measured in the present study, may have changed after PTMC. This change may also contribute to the symptomatic improvement.

Afterload reduction with vasodilators and diuretics decreases mitral regurgitation during upright exercise in advanced heart failure

In advanced heart failure, mitral regurgitation increases the burden of the failing ventricle and decreases effective stroke volume. Although tailored afterload reduction decreases mitral regurgitation at rest, it is not known if this benefit is maintained during upright exercise. Simultaneous radionuclide ventriculography and thermodilution stroke volumes were compared to measure the forward ejection fraction in 10 patients during upright bicycle exercise before and after therapy with vasodilators and diuretics tailored to decrease pulmonary capillary wedge pressure and systemic vascular resistance. Ventricular volumes, total ejection fraction and the forward ejection fraction did not change during exercise at baseline. At rest, tailored therapy decreased average pulmonary capillary wedge pressure from 36 to 19 mm Hg (p less than 0.01), systemic vascular resistance from 1,570 to 1,210 dynes.s.cm-5 (p less than 0.05), and left ventricular volume index from 251 to 177 ml/m2 (p less than 0.01), while increasing the forward ejection fraction from 0.53 to 0.85 (p less than 0.01) without change in total ejection fraction (0.18 from 0.17). During steady state exercise at low work load, tailored therapy decreased left ventricular volume index from 279 to 213 (p less than 0.05) and increased forward ejection fraction from 0.52 to 0.79 (p less than 0.01) without change in total ejection fraction (0.20 from 0.19). The total stroke volume during exercise was not increased after therapy; the increase in forward stroke volume after therapy appeared to result instead from the decrease in mitral regurgitant flow. The benefits of tailored afterload reduction are maintained throughout upright exercise.

Effects of DBcAMP on exercise capacity in patients with and without chronic heart failure

The acute effects of vasodilation on exercise capacity in cardiac patients with (group 1) and without (group 2) congestive heart failure were studied using dibutyryl cyclic AMP (DBcAMP). Exercise was performed on an upright bicycle ergometer using a graded protocol. DBcAMP increased cardiac output and decreased pulmonary capillary wedge pressure and systemic vascular resistance both at rest and during maximal exercise in these two groups. However, before and after DBcAMP neither exercise duration (371 +/- 52 seconds vs. 388 +/- 44, NS, in group 1, 645 +/- 148 vs. 635 +/- 143 seconds, NS, in group 2, respectively) nor maximal oxygen consumption (12.8 +/- 2.3 ml/kg/min vs. 13.1 +/- 1.6, NS, in group 1, 20.3 +/- 1.4 vs. 20.1 +/- 1.5, NS, in group 2, respectively) was improved. In both groups the arteriovenous oxygen differences were lower at rest and during exercise performed while on DBcAMP than in the control state. In group 2 patients excess vasoconstriction mediated by abnormally increased neurohormonal activities or edema were absent. Failure of the vasodilator to increase exercise capacity is probably due to nonspecific vasodilation and maldistribution of increased cardiac output, and not to tight vasoconstriction or narrowed arteriolar lumen.

Vasodilator therapy without converting-enzyme inhibition in congestive heart failure--usefulness and limitations

Despite a well-established rationale for pharmacologically induced arterial and venous vasodilatation in congestive heart failure, the clinical usefulness of long-term vasodilator therapy without concomitant converting-enzyme inhibition generally has been disappointing. With the exception of nitrates and, possibly, the combination of nitrates and hydralazine, the use of converting-enzyme inhibitors in many aspects appears preferable in the majority of patients. This article reviews the pathophysiology of inappropriate vasoconstriction in heart failure, the cellular mode of action of the various vasodilators, hemodynamic effects with respect to the peripheral site of action, clinical usefulness and limitations of different vasodilators, and the various determinants of clinical efficacy. Finally, an attempt is made to assess when and how to introduce vasodilator treatment with and without concomitant ACE inhibition.

Clinical pharmacokinetics and therapeutic use of hydralazine in congestive heart failure

Hydralazine (1-hydrazinophthalazine) has been used extensively in the treatment of hypertension and congestive heart failure and produces arteriolar vasodilation, in part, mediated by prostaglandins. Its associated reflex baroreceptor-mediated responses of tachycardia and increased ejection velocity are attenuated in congestive heart failure. A direct inotropic effect has been attributed to the drug. Pharmacokinetic data indicate hydralazine is absorbed well from the gastrointestinal tract, and has an extensive and complex metabolism depending on acetylator status: slow acetylators undergo primary oxidative metabolism, while rapid acetylators are acetylated. Half-lives, clearances and bioavailability of the drug are not significantly altered in congestive heart failure compared with hypertensive patients. A wide range of dosages in heart failure has been noted (150 to 3000 mg/24h), and may related to a saturation of the first-pass effect. Hydralazine improves haemodynamics in the short term in patients with increased peripheral vascular resistance, and has variable effects on pulmonary capillary wedge and left ventricular filling pressures. Prediction of the short term clinical response is difficult and appears to be independent of pharmacokinetics. A meta analysis did not demonstrate long term efficacy of hydralazine alone in heart failure, but combination therapy with nitrates has been shown to improve survival and exercise performance in patients with mild to moderate heart failure. Side effects are common and are dependent on dose, duration and acetylator status.

Vasodilators as first-line therapy for congestive heart failure: a comparative hemodynamic study of hydralazine, digoxin, and their combination

Although digitalis and vasodilators both enhance cardiac performance in patients with congestive heart failure, their relative efficacy is unknown. Accordingly, the acute hemodynamic effects of intravenous hydralazine (0.15 mg/kg), digoxin (1.0 mg), and the hydralazine-digoxin combination were evaluated in 14 normotensive heart failure patients at sitting rest, nine of whom were also studied during submaximal upright bicycle exercise. Hemodynamic responses at rest and exercise were similar. Cardiac output and stroke volume rose with both agents, the increase in cardiac output with hydralazine exceeding that with digoxin at rest. Left and right ventricular filling pressures declined equally. Systemic arterial mean pressure and total systemic vascular resistance fell with hydralazine, while, with digoxin, systemic arterial mean pressure increased and total systemic vascular resistance was unchanged. The hydralazine-digoxin combination produced increases in cardiac output and stroke volume that were greater than with either drug alone, and that equalled the sum of the drugs' individual effects; reductions in ventricular filling pressures were similar to the single-drug interventions. Thus, hydralazine is at least as effective as digoxin in improving cardiac function over the short term. Vasodilators may constitute an acceptable alternative to digitalis as initial therapy for congestive heart failure, except where a reduction in systemic arterial pressure is potentially deleterious. Use of combined treatment produces greater increases in cardiac output than with either drug alone, but requires risking the toxicities of two agents.

Static exercise with congestive heart failure and the response to vasodilating drugs

The hemodynamic response to static exercise in 28 patients with congestive heart failure (CHF) was compared with that in 8 control subjects. Static handgrip exercise at 50% of the maximal voluntary contraction was performed to fatigue. In patients with CHF, pulmonary arterial wedge pressure increased from 20 +/- 18 to 31 +/- 10 mm Hg (p less than 0.001) (mean +/- standard deviation) and systemic vascular resistance increased from 1,730 +/- 454 to 2,151 +/- 724 dynes s cm-5 (p less than 0.001). Although cardiac index did not change significantly, stroke volume index and stroke work index decreased from 24 +/- 6 to 20 +/- 6 ml/m2 (p less than 0.001) and 28 +/- 11 to 25 +/- 12 g-m/s2 (p less than 0.05), respectively. In control subjects, pulmonary arterial wedge pressure did not change significantly; cardiac index increased from 3.6 +/- 0.3 to 4.0 +/- 0.4 liters/min/m2 (p less than 0.05) and systemic vascular resistance increased slightly, from 1,011 +/- 186 to 1,106 +/- 180 dynes s cm-5 (p less than 0.05). The effects of arterial dilation with hydralazine on the response to static exercise were assessed in 10 of the patients with CHF. Compared with predrug exercise, cardiac index increased 68% (p less than 0.01), stroke volume index increased 76% (p less than 0.01) and systemic vascular resistance decreased 47% (p less than 0.01) after administration of hydralazine. Thus, static exercise can have adverse effects on cardiac performance in patients with CHF.(ABSTRACT TRUNCATED AT 250 WORDS)

Congestive heart failure

A review of the epidemiology, pathophysiology, and treatment of congestive heart failure is presented, with particular attention given to newer modalities of therapy.

Vasodilator therapy

Vasodilators are a group of drugs with various degrees of arteriolar or venous dilatation used in the treatment of congestive heart failure when symptoms persist after digoxin and diuretic therapy. Nitrates and captopril provide the most consistent improvement in symptoms. Reduced mortality rates in congestive heart failure with vasodilator therapy has not been demonstrated, and prediction of clinical response to therapy is difficult.

Lactate production during maximal and submaximal exercise in patients with chronic heart failure

In patients with chronic heart failure whose cardiac output response to exercise is impaired, determination of anaerobic threshold may provide a useful and objective approach to grade the severity of heart failure. In such patients performing upright treadmill exercise to exhaustion, this study examined the reproducibility of the response of cardiac output and mixed venous lactate concentration when the exercise test was repeated the same or next day, the nature of this response after rest and exercise cardiac output levels were augmented by the cardiotonic agent amrinone and the response of lactate during symptom-limited submaximal exercise performed at either aerobic or anaerobic levels of work for each patient. Findings were: 1) the response of cardiac output and mixed venous lactate was reproducible (p less than 0.05) when assessed either the same or the next day; 2) when exercise cardiac output was increased (p less than 0.05) by oral amrinone therapy, the increase in lactate was delayed (p less than 0.05) to higher levels of muscular work and this was not true when cardiac output was unchanged; and 3) only submaximal anaerobic exercise was symptom limited and associated with an increase in lactate concentration. Thus, the lactate response and anaerobic threshold determination should prove useful to assess the severity of chronic stable heart failure and its response to pharmacologic intervention. The submaximal anaerobic exercise test may provide additional insights into the effort intolerance these patients experience.

Acute and long-term effects of enalapril on the cardiovascular response to exercise and exercise tolerance in patients with congestive heart failure

Enalapril is a recently developed angiotensin-converting enzyme inhibitor that improves cardiac function at rest in patients with congestive heart failure. This study investigated the acute effects of enalapril on the cardiovascular response to exercise, and then evaluated the long-term effects of enalapril on exercise capacity and functional status during a 12 week placebo-controlled trial in patients with heart failure. Ten patients underwent hemodynamic monitoring while at rest and during incremental bicycle exercise before and after 5 to 10 mg of enalapril orally. At rest, enalapril decreased mean blood pressure 13% (p less than 0.01) and systemic vascular resistance 20% (p less than 0.05) and increased stroke volume index 21% (p less than 0.01). During maximal exercise, enalapril decreased systemic vascular resistance and increased both cardiac and stroke volume indexes. Enalapril acutely increased exercise duration (p less than 0.05) and maximal oxygen consumption (p less than 0.001). These 10 patients and an additional 13 patients were then randomized to either placebo or enalapril treatment and followed up for 12 weeks. Of the 11 patients assigned to active treatment, 73% considered themselves improved compared with 25% of the patients assigned to placebo treatment (p less than 0.02). During long-term treatment, exercise capacity increased in patients receiving enalapril (p less than 0.001) but was unchanged in patients receiving placebo (intergroup difference, p less than 0.05). During long-term treatment, no adverse effects of enalapril occurred. Thus, enalapril improves cardiac function at rest and during exercise. Compared with placebo, maintenance therapy with enalapril results in symptomatic improvement and increased exercise capacity.

Effects of diltiazem on cardiac function and regional blood flow at rest and during exercise in a conscious rat preparation of chronic heart failure (myocardial infarction)

The effects of intravenous infusion of diltiazem on regional blood flow (radioactive microspheres), hemodynamics, and maximum rate of oxygen consumption were evaluated in conscious rats with congestive heart failure caused by large myocardial infarction (n = 10, infarct size 41.8% of left ventricle) and compared with data obtained from rats subjected to sham surgical procedures (n = 9). In both groups data were obtained at rest and during submaximal treadmill exercise during alternate infusion of diltiazem and saline. In the group with heart failure, diltiazem increased stroke volume at rest and during exercise (p less than .05), reduced heart rate (p less than .05), and improved cardiac output during exercise (p less than .05) without increasing left ventricular end-diastolic pressure in any of the animals. Blood flow to renal and splanchnic circulations was reduced in the group with heart failure but was increased by diltiazem to values similar to those observed in sham-operated animals. Although skeletal muscle flow during exercise was significantly increased by the drug, maximal rate of oxygen consumption was not, indicating unchanged oxygen availability within working muscle. Thus diltiazem caused redistribution of blood flow to kidney and gut in animals with myocardial infarction and failure, thereby restoring blood flow to circulatory beds known to be impaired in this setting.

Exercise and hypertension

Hypertension is a major risk factor for atherosclerosis. In this article the authors review the use of physical activity as therapy for elevated blood pressure and explore the hemodynamic effects of exercise among patients with treated and untreated hypertension. Recommendations concerning the use of exercise in the management of hypertension are outlined.

Effect of hydralazine on nutritive flow to working canine gracilis skeletal muscle

The direct smooth muscle vasodilator hydralazine has been used to treat exertional fatigue in patients with chronic heart failure. However, prior studies suggest that arteriolar vasodilators such as hydralazine may actually impair nutritive flow to working skeletal muscle by interfering with the distribution of blood flow within muscle. To investigate this possibility, tension development and metabolism were measured in nine vascularly isolated gracilis muscle preparations perfused at 90 mm Hg and stimulated to contract progressively at rates of 1, 3 and 6/s with each stage lasting 3 minutes. Studies were then repeated after 30 minutes of intraarterial hydralazine (0.02 to 0.12 mg/min). At rest, hydralazine decreased mean vascular resistance (+/- SEM) from 15.1 +/- 1.4 to 8.6 +/- 0.9 X 10(2) units (p less than 0.001) and increased blood flow from 6.4 +/- 0.7 to 11.4 +/- 1.2 ml/min (p less than 0.001), but did not change oxygen consumption (VO2) control, 18 +/- 1 versus hydralazine, 17 +/- 2 microliter/min). Hydralazine also decreased vascular resistance and increased flow at a contraction rate of 1/s, but not at 3 and 6/s. Hydralazine had no effect on maximal VO2 (control, 254 +/- 18 versus hydralazine, 236 +/- 19 microliter/min), maximal developed tension (control, 353 +/- 90 versus hydralazine, 334 +/- 74 kg X min) or the response in venous lactate (control, 20.6 +/- 2.3 versus hydralazine, 18.1 +/- 2.0 mg/dl). Hydralazine also did not change muscle metabolism and function at contraction rates of 1 and 3/s. These data suggest that hydralazine does not adversely affect nutritive flow to working skeletal muscle.

Hydralazine therapy in chronic congestive heart failure. Sustained central and regional hemodynamic responses

Central and regional hemodynamic parameters were evaluated at baseline and following three months of placebo or hydralazine therapy (100 mg orally every eight hours) in 20 patients with idiopathic dilated cardiomyopathy. Both control (placebo) and hydralazine groups were comparable with respect to functional classification (New York Heart Association classes III and IV) and baseline hemodynamic variables. In the hydralazine group, cardiac index increased 25 percent (2.4 +/- 0.4 to 3.0 +/- 0.5 liters/minute/m2), renal blood flow increased 26 percent (648 +/- 199 to 815 +/- 229 ml/minute), and limb blood flow was augmented by 35 percent (6.8 +/- 3.0 to 9.2 +/- 4.6 ml/dl/minute) with long-term therapy. These changes were significant (all p less than 0.05) when compared with both baseline values and values in the control group. Both central and regional hemodynamic parameters remained unaltered in the control group. Long-term hydralazine therapy (three months) elicited a favorable circulatory response in this group of patients with chronic congestive heart failure. Central or regional hemodynamic tolerance to oral hydralazine failed to develop in the majority of patients.

Amrinone in the treatment of chronic cardiac failure

The efficacy and safety of oral amrinone were examined in 17 patients with moderately severe to severe heart failure that was refractory to standard medical therapy and vasodilators. The short-term and 28 week response to open amrinone therapy was assessed first, followed by a placebo-controlled, double-blind withdrawal study of two 13 week stages in nine patients. Rest and exercise ventricular function were determined before and after 32 hours of amrinone; aerobic capacity was serially assessed. After 2 hours, 1.64 mg/kg amrinone produced a 40% (p less than 0.001) increase in cardiac output and a 32% (p less than 0.02) decrease in pulmonary wedge pressure without altering heart rate or blood pressure. The exercise cardiac index-wedge pressure curve obtained 32 hours after the first oral dose was significantly shifted (p less than 0.05) above control values. A sustained improvement in maximal oxygen uptake was noted during long-term open amrinone therapy. Subsequently, seven of the patients randomized to placebo therapy had a significant deterioration of symptoms or exercise tolerance, or both. After 4 weeks of readministration of amrinone, clinical stability was once again established and exercise tolerance was improved by Weeks 8 to 16. Adverse effects of thrombocytopenia (one patient) and hepatic dysfunction (one patient) attributable to amrinone were observed. It is concluded that amrinone is effective in the long-term treatment of chronic cardiac failure.

Vasodilator and inotropic therapy for severe chronic heart failure: passion and skepticism

Although substantial progress has been made in the last 5 years in the development of vasodilator and inotropic drugs for the management of patients with severe chronic heart failure, much of the enthusiasm that surrounded the introduction of many of these agents has subsequently been tempered by reports of drug failure or adverse reactions. In this review and analysis, currently available vasodilator and inotropic agents are critically and comparatively evaluated to assess their respective advantages and limitations. It is apparent that the ability of most of these drugs to produce substantial clinical benefits in patients with severe heart failure has probably been overstated. Therapy fails to achieve the desired clinical results all too frequently, possibly as the result of: the choice of an ineffective drug; the administration of an effective drug in subtherapeutic doses; the administration of an effective drug to improperly selected patients; the failure of initial hemodynamic benefits to be sustained; the occurrence of severe or serious adverse reactions; and the failure to alter concomitant therapy appropriately. The present analysis indicates that there is no uniformly effective or safe vasodilator or inotropic drug for patients with severe heart failure; all agents have important limitations. Of the available therapeutic choices, however, long-term converting enzyme inhibition appears to produce more consistent hemodynamic and clinical benefits with an acceptable degree of adverse reactions than other pharmacologic approaches for the management of these severely ill patients.

Trimazosin in chronic congestive heart failure: improved left ventricular function at rest and during exercise

The hemodynamic effects of the oral vasodilator trimazosin were evaluated in patients with chronic congestive heart failure (CHF), initially over a 72-hour period (13 patients), and after 3 months of maintenance therapy (seven patients). During the initial evaluation, cardiac index and stroke work index increased an average of 24% and 37% respectively, and pulmonary capillary wedge pressure decreased by 26%. These beneficial hemodynamic effects were maintained during supine bicycle exercise. After 3 months of maintenance therapy, cardiac index (+30%) and stroke work index (+38%) remained elevated, and pulmonary capillary wedge pressure was lower (-38%). Improved hemodynamics during exercise were also seen after maintenance therapy. Withdrawal of trimazosin was associated with deterioration in hemodynamics and left ventricular function. Thus trimazosin has the potential to cause sustained improvement in left ventricular function, both at rest and during exercise, in patients with chronic CHF.

Improvement in exercise capacity despite cardiac deteriora tion: nonivasive assessment of long-term therapy with amrinone in severe heart failure

Seven patients with severe congestive heart failure (CHF) were treated with oral amrinone for a mean duration of 39 weeks (range 16 to 72). During the first week of therapy, exercise capacity as assessed on a treadmill using the Naughton protocol, increased substantially from 7.6 +/- 4.2 to 12.1 +/- 4.4 minutes (p less than 0.01). At an early period of follow-up (8 to 12 weeks), a further significant increase in exercise capacity to 14.7 +/- 5.0 minutes (p less than 0.05) was demonstrated, while at a later follow-up exercise capacity had decreased to 11.4 +/- 6.8 minutes (p less than 0.05). This was still significantly greater than prior to amrinone therapy (p less than 0.01). Left ventricular ejection fraction was increased from 14 +/- 4 to 19 +/- 4% (p less than 0.05) during the first week of therapy, but was not significantly different from control at the early and late periods of follow-up. Left ventricular end-diastolic dimension index increased from control value of 43 +/- 5 to 47 +/- 7 mm/m2 (p less than 0.01) at the late period of follow-up. Thus long-term amrinone therapy resulted in a substantial improvement in exercise capacity despite a slow, but progressive decline in cardiac performance.

Hydralazine therapy in severe chronic heart failure: inability of radionuclide left ventricular ejection fraction measurement to predict the hemodynamic response

Simultaneous hemodynamic and radionuclide angiographic assessment was made at rest and during exercise in nine patients with severe chronic congestive heart failure to determine the value of radionuclide left ventricular ejection fraction measurement in predicting the hemodynamic response to short-term treatment with oral hydralazine. Hydralazine, 50 to 100 mg orally every 6 hours, produced significant increases in cardiac index and stroke volume index at rest and during exercise (p less than 0.01) and in left ventricular stroke work index at rest (p less than 0.01) and during exercise (p less than 0.05), significant decreases in systemic vascular resistance at rest and during exercise (p less than 0.01) and significant increases in radionuclide angiographic left ventricular ejection fraction at rest (control 0.21 +/- 0.06 vs. hydralazine 0.26 +/- 0.07, p less than 0.01) and during exercise (control 0.21 +/- 0.08 vs. hydralazine 0.24 +/- 0.09, p less than 0.05). However, there were no statistically significant correlations between changes in radionuclide ejection fraction with hydralazine and changes in hemodynamic variables with hydralazine, either at rest or during exercise. Patients responding hemodynamically to hydralazine could not be separated from those not responding on the basis of the radionuclide ejection fraction at rest or changes in ejection fraction with hydralazine.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute inotropic stimulation with dopamine in severe congestive heart failure: beneficial hemodynamic effect at rest but not during maximal exercise

Hemodynamic and metabolic effects of dopamine were studied at rest and during maximal exercise in 13 patients with severe chronic congestive heart failure (CHF). During exercise before the administration of dopamine, the stroke volume index increased from 17.1 +/- 5.2 ml/m2 at rest to 28.1 +/- 10.9 ml/m2 (p less than 0.001) at exhaustion, while pulmonary capillary wedge (PCW) pressure increased from 22.7 +/- 12.7 to 43.9 +/- 11.9 mm Hg (p less than 0.001). The arteriovenous oxygen difference increased from 8.9 +/- 2.3 ml/100 ml to 12.4 +/- 2.0 ml/100 ml (p less than 0.001) and oxygen uptake increased from 3.5 +/- 0.6 0.6 to 11.9 +/- 2.5 ml/kg/min (p less than 0.001). At rest, dopamine increased the stroke volume index to 23.3 +/- 8.1 ml/m2 (p less than 0.001) and reduced the PCW pressure to 20.5 +/- 1.1 mm Hg (p less than 0.05). However, during maximal exercise, the stroke volume index and PCW pressure were not changed by dopamine: 28.1 +/- 10.9 versus 28.6 +/- 10.2 ml/m2 (difference not significant [NS]) and 43.9 +/- 11.9 versus 42.5 +/- 11.2 mm Hg (NS), respectively. In contrast, the maximal heart rate achieved during exercise was significantly higher with dopamine, 140.3 +/- 29.3 versus 136.0 +/- 29.7 beats/min (p less than 0.05), which contributed to a slight augmentation in the maximal cardiac index, 3.82 +/- 1.13 versus 3.64 +/- 1.17 liters/min/m2 (p less than 0.05). Nonetheless, neither peak arteriovenous oxygen difference nor maximal oxygen uptake were significantly changed by dopamine.(ABSTRACT TRUNCATED AT 250 WORDS)

Hemodynamic and clinical response to three-day infusion of sulmazol (AR-L 115 BS) in severe congestive heart failure

Sulmazol (AR-L 115 BS) is a new positively inotropic drug with arterial and venous vasodilating properties. We studied the effects of sulmazol (three-day infusion) on clinical tolerance, hemodynamics, and blood gas levels in ten patients with severe chronic heart failure. The hemodynamic monitoring included a Swan-Ganz catheter in the pulmonary artery and a radial catheter. Blood gas levels were determined on samples of arterial and mixed venous blood. After 24 hours of infusion, there was a significant increase in cardiac index (2 to 2.5 L/min/sq m; p less than 0.005) and a significant decrease in pulmonary wedge pressure (28 to 19 mm Hg; p less than 0.001) and in right atrial pressure (7 to 4 mm Hg; p less than 0.001) without significant changes in heart rate and systolic blood pressure. These beneficial effects lasted during the three days of infusion. Oxygen delivery was significantly increased (350 to 443 ml/min/sq m; p less than 0.005) without significant change in arterial oxygen tension. The side effects included nausea, vomiting, anorexia, and mild thrombocytopenia. We conclude that sulmazol is a potent drug which may improve severely deteriorated left and right ventricular function in patients with chronic refractory heart failure without affecting the heart rate and the systolic blood pressure.

Effect of hydralazine on perfusion and metabolism in the leg during upright bicycle exercise in patients with heart failure

The aerobic exercise capacity of patients with chronic heart failure is frequently impaired because of inadequate O2 transport to working skeletal muscle. To determine whether hydralazine improves O2 transport to working muscle, we examined the effect of intravenous hydralazine on blood flow (measured by thermodilution) and metabolism in the leg during maximal upright bicycle exercise in 10 patients with chronic heart failure. Hydralazine increased maximal exercise cardiac output (5.6 +/- 0.7 to 6.7 +/- 0.6 l/min; p less than .01) and decreased systemic O2 extraction (79 +/- 3% to 65 +/- 2%; p less than .01) but did not alter maximal O2 uptake (787 +/- 105 vs 779 +/- 82 ml/min). Leg blood flow at maximal exercise increased from 1.6 +/- 0.2 to 2.1 +/- 0.4 l/min (p less than .03); the proportion of cardiac output delivered to the leg remained unchanged (59 +/- 3% vs 57 +/- 9%). This increase in flow was associated with a decrease in O2 extraction in the leg (84 +/- 2% to 79 +/- 2%; p less than .01) and no change in peak femoral venous lactate (59.1 +/- 7.4 vs 54.1 +/- 5.3 mg/dl), suggesting that there is functional or anatomic shunting of the augmented limb flow rather than delivery to metabolizing muscle. These data suggest that hydralazine augments flow to the exercising limb in patients with heart failure but that this augmented flow does not increase oxygen availability within working muscle.

Vasodilator therapy in chronic congestive heart failure

Vasodilator agents are relatively new additions to the armamentarium for the management of patients with congestive heart failure. Myocardial failure, irrespective of the aetiology, tends to create a vicious cycle characterised by reduced cardiac output and elevated systemic vascular resistance, which further decrease cardiac output by increasing left ventricular ejection impedance. The rationale for the use of vasodilators is to interrupt the vicious cycle by decreasing the left ventricular ejection impedance by peripheral vasodilatation. Although most vasodilator agents produce qualitatively similar haemodynamic responses, quantitatively their haemodynamic effects differ considerably. Knowledge of the haemodynamic effects of the various vasodilators helps in the selection of a particular drug for the management of such patients. This article reviews the mechanisms of action, haemodynamic effects, pharmacokinetics, clinical usage and adverse effects of non-parenteral vasodilator agents currently available for the management of patients with chronic heart failure.

New perspectives on therapeutic application of nitrates as vasodilator agents for severe chronic heart failure

Although nitrates produce marked decreases in ventricular filling pressures in patients with severe heart failure, their therapeutic value has long been believed to be limited because they were thought to exert minimal arterial dilating effects. Recently, however, new conceptual approaches to vasodilator drugs have been developed that have challenged this traditional view. These new perspectives indicate that nitrates exert dilator actions on both the arterial and venous circulations, and reduce both preload and afterload; such balanced circulatory responses are particularly evident when large doses of these drugs are used. Cardiac output increases markedly with nitrates in patients with a greatly increased systemic vascular resistance before treatment or with significant mitral regurgitation. The major reason for the limited increases in cardiac output noted in previous studies is the inclusion of patients with heart failure whose pretreatment values for cardiac output were within normal limits; in these persons nitrates markedly activate neurohumoral vasoconstrictor mechanisms that counteract the arterial dilating actions of these drugs. Long-term nitrate therapy attenuates exercise-induced increases in pulmonary venous pressures, which permit patients to undergo repeated submaximal exercise with fewer symptoms; this improves physical conditioning and exercise capacity, even in the absence of drug-related changes in cardiac output. The long-term hemodynamic and clinical benefits of nitrates in heart failure have been confirmed by two independent randomized double-blind placebo-controlled clinical trials.

Regression of myocardial cellular hypertrophy with vasodilator therapy in chronic congestive heart failure associated with idiopathic dilated cardiomyopathy

Forty-nine patients with idiopathic dilated cardiomyopathy (IDC) were evaluated to determine the hemodynamic and morphologic effects of vasodilator therapy. Hydralazine (225 mg/day, H), isosorbide dinitrate (160 mg/day, I), and combination H + I therapy were compared with placebo (P) at baseline and after 3 months of continuous therapy. Thirty-three randomly assigned patients completed the study. Hemodynamic parameters included the echocardiographic percent change of left ventricular diameter (% delta D), the systolic time intervals ratio of preejection period to left ventricular ejection time (PEP/LVET), the pulmonary capillary wedge pressure, mean pulmonary artery pressure, cardiac index, systemic vascular resistance, and pulmonary vascular resistance. An endomyocardial biopsy was performed at baseline and after 3 months; the myocardial cell diameter of 50 cells per biopsy was measured. During the 3-month study 5 patients died; there was not a significant difference among the groups in the number of deaths. The % delta D and PEP/LVET did not change in the P or I groups but did improve significantly from baseline in the H and H + I groups. The pulmonary capillary wedge and mean pulmonary artery pressures and the pulmonary vascular resistance did not change in the P or H groups but did decrease significantly in the I and H + I groups. The P and I groups did not have improvement in systemic vascular resistance or cardiac index, whereas the H group had a decrease in systemic vascular resistance and an increase in cardiac index from 2.5 +/- 0.4 to 3.1 +/- 0.4 liters/min/m2 (p less than 0.05). The H + I group also had a decrease in systemic vascular resistance; the cardiac index increased from 2.3 +/- 0.4 to 3.1 +/- 0.4 liters/min/m2 (p less than 0.01). Myocardial cell diameter did not change in the P or I group. Cell diameter of the H group decreased from 25.4 +/- 3.1 microns at baseline to 23.1 +/- 3.8 microns (p less than 0.05) after 3 months of continuous therapy. The H + I group decreased its cell diameter from 23.9 +/- 3.7 to 22.2 +/- 2.2 microns (p less than 0.05). Compared with P and H, patients treated with I alone or H + I had a significant reduction of preload. In contrast to P and I, H alone and H + I elicited improvement in parameters of inotropy and afterload, and this improvement was accompanied by a reduction in cell diameter. Chronic therapy of heart failure with H and H + I effects a persistent augmentation of cardiac function and improvement of myocardial cellular morphology.

Vasodilator therapy for acute myocardial infarction and chronic congestive heart failure

Vasodilator therapy is useful adjunctive therapy in the management of both acute and chronic heart failure. Arteriolar dilators, such as hydralazine, increase cardiac output by decreasing the elevated peripheral vascular resistance that occurs in heart failure. Venodilators, such as nitrates, decrease ventricular filling pressures by redistributing blood so that more is pooled in peripheral veins. Vasodilators that produce both effects (nitro-prusside, prazosin, captopril, for example) are usually helpful in short-term improvement of hemodynamics. Long-term treatment with nonparenteral vasodilators often reduces symptoms and increases exercise tolerance, although there is inconclusive evidence regarding the effects of these agents on mortality. In acute myocardial infarction, intravenous vasodilators frequently improve cardiac performance. Evidence regarding their beneficial effects on infarct size and immediate mortality is encouraging but inconclusive. There is little evidence that they prolong life in patients who survive cardiogenic shock and leave the hospital. Thus, vasodilators can improve hemodynamics and lessen symptoms, but more evidence is needed regarding their long-term effects on survival.

Failure of dobutamine to increase exercise capacity despite hemodynamic improvement in severe chronic heart failure

The acute hemodynamic and metabolic effects of dobutamine administered during exercise were studied in 8 patients with severe chronic heart failure. Exercise was performed on an upright bicycle ergometer using a graded protocol. During exercise performed without administration of dobutamine, exhaustion occurred after 4.5 +/- 1.2 minutes of exercise. The cardiac index increased from 1.61 +/- 0.25 to 2.67 +/- 0.59 liters/min/m2 (p less than 0.001), the arteriovenous oxygen difference from 7.8 +/- 1.7 to 12.5 +/- 2.4 ml/100 ml (p less than 0.001), and oxygen uptake from 7.9 +/- 3.0 to 41.2 +/- 15.7 mg/100 ml (p less than 0.001). During exercise performed with the administration of dobutamine, the cardiac index was significantly greater than during the control state, 3.23 +/- 0.78 versus 2.67 +/- 0.59 liters/min/m2 (p less than 0.001), while the arteriovenous oxygen difference was significantly lower, 11.2 +/- 2.1 vs 12.5 +/- 2.4 ml/100 ml (p less than 0.01). The arterial lactate level was not significantly changed, 45.3 +/- 17.6 versus 41.2 +/- 15.7 mg/100 ml. Although the dobutamine level tended to increase maximal oxygen uptake compared with the control period of exercise, 9.1 +/- 1.2 versus 8.5 +/- 1.4 ml/kg/min (p less than 0.05), it did not significantly increase exercise capacity, 4.8 +/- 1.5 versus 4.5 +/- 1.2 min. Thus administration of dobutamine in patients with severe chronic heart failure increased the cardiac index during maximal exercise but failed to increase exercise capacity. Since arteriovenous oxygen difference is reduced, dobutamine probably increases blood flow to the nonexercising tissues and not to the actively metabolizing muscles.

Regional and systemic metabolic effects of angiotensin-converting enzyme inhibition during exercise in patients with severe heart failure

The acute hemodynamic and metabolic effects of captopril therapy were studied in 12 patients with severe heart failure during maximal exercise performed on an upright bicycle ergometer. During the control period, exhaustion occurred after 4.2 +/- 2.7 minutes of exercise. Cardiac index increased from 1.54 +/- 0.36 l/min/m2 at rest to 3.39 +/- 1.54 l/min/m2 (p less than 0.001) at exhaustion; systemic arteriovenous oxygen difference increased from 8.8 +/- 2.1 to 12.8 +/0 2.4 ml/100 ml (p less than 0.001) and oxygen uptake from 3.4 +/- 0.5 to 10.8 +/- 3.0 ml/kg/min (p less than 0.001). Pulmonary arterial oxygen content decreased from 7.3 +/- 1.3 to 3.7 +/- 1.5 ml/100 ml (p less than 0.001) and femoral vein oxygen content from 5.0 +/- 1.7 to 2.5 +/- 1.2 ml/100 ml (p less than 0.001). During captopril therapy, cardiac index significantly increased both at rest (1.83 +/- 0.54 vs 1.54 +/- 0.36 l/min/m2, p less than 0.01) and during maximal exercise (3.67 +/- 1.51 vs 3.39 +/- 1.54 l/min/m2, p less than 0.01). Systemic arteriovenous oxygen difference decreased significantly at rest, from 8.8 +/- 2.1 to 7.7 +/- 2.1 ml/100 ml (p less than 0.01) and during maximal exercise from 12.8 +/- 2.4 to 12.3 +/- 2.2 ml/100 ml (p less than 0.01). Pulmonary arterial oxygen content at exhaustion was significantly higher during captopril therapy than during the control period (4.1 +/- 1.1 vs 3.7 +/- 1.5 ml/100 ml, p less than 0.05), while femoral venous blood content was unchanged. Captopril therapy did not significantly increase maximal oxygen uptake or exercise duration. Thus, the acute administration of captopril to patients with severe heart failure does not increase exercise capacity despite improved cardiac performance. Moreover, captopril therapy does not acutely result in metabolic benefits to the skeletal muscles during exercise.

Effects of acute and chronic minoxidil administration on rest and exercise hemodynamics and clinical status in patients with severe, chronic heart failure

The effects of acute and chronic oral administration of the vasodilator minoxidil on hemodynamics, oxygen consumption, exercise performance, and clinical status were investigated in 10 patients with severe, chronic heart failure refractory to digitalis and diuretic therapy. The cardiac index was 1.99 +/- 0.38 liters/min/m2 at rest and 2.88 +/- 0.79 at symptom-limited maximal exercise on conventional therapy, compared with 2.64 +/- 0.33 liters/min/m2 at rest and 3.55 +/- 0.84 at maximal exercise after short-term minoxidil administration (p less than 0.02, control versus minoxidil at both rest and exercise). Stroke volume was increased after minoxidil treatment, without significant effect on heart rate. Systemic vascular resistance was decreased by minoxidil from 2,050 +/- 722 to 1,325 +/- 374 dynes . s/cm-5 at rest and from 1,500 +/- 830 to 1,206 +/- 589 dynes . s/cm-5 at maximal exercise (p = 0.01, control versus minoxidil). No significant effect was observed on left ventricular filling, right atrial, or mean pulmonary arterial pressure, but pulmonary vascular resistance decreased both at rest and on exercise (p less than 0.05). Maximal exercise oxygen consumption increased from 8.9 +/- 3.2 ml/kg/min on conventional therapy to 10.5 +/- 2.4 on minoxidil therapy (p less than 0.03), median maximal exercise work load increased from 25 to 50 W and medium exercise duration increased from 6.0 to 9.0 minutes. On chronic minoxidil administration all 5 patients who completed a scheduled 6 week follow-up showed symptomatic improvement. However, worsening edema developed in all patients, requiring increased diuretic dosage and close supervision. Symptoms of ischemic heart disease worsened in 2 of 10 patients. We tentatively conclude that minoxidil may be a useful vasoactive agent in the pharmacologic therapy of severe chronic heart failure.

Variable clinical response to long-term angiotensin inhibition in severe heart failure: demonstration of additive benefits of alpha-receptor blockade

The effects of long-term therapy with captopril (CPT) were studied in 11 patients with severe chronic congestive heart failure (CHF). At initiation of therapy, cardiac index increased from 1.88 +/- 0.56 to 2.12 +/- L/min/m2 (p less than 0.05), while pulmonary capillary wedge pressure decreased from 27.9 +/- 7.2 to 17.8 +/- 7.6 mm Hg (p less than 0.01). This improvement in resting cardiac performance was maintained during maximal exercise; however, maximal oxygen uptake was not acutely increased by CPT. During chronic therapy, 6 of 11 patients showed symptomatic improvements; however, only three of these six patients demonstrated an increase in maximal oxygen uptake, which was measured at an average of 13.2 weeks following initiation of therapy. Five patients did not improve clinically during chronic therapy. In these patients, hemodynamic measurements that had improved initially after CPT returned to baseline values during chronic therapy. The addition of prazosin to chronic CPT therapy elicited a beneficial hemodynamic response in all five patients. Thus, the results of long-term therapy with CPT are variable in patients with severe CHF, and symptomatic improvement does not always correlate with objective measurement of exercise capacity. Combined alpha-adrenergic blockade and angiotensin-converting enzyme inhibition appears safe in patients who failed to exhibit a sustained improvement on CPT alone.

Patterns of exercise response in patients with severe left ventricular dysfunction: radionuclide ejection fraction and hemodynamic cardiac performance evaluations

To evaluate the exercise response of the severely diseased left ventricle, 13 patients with chronic congestive cardiomyopathy with mean resting ejection fraction (EF) of 18.8 +/- 9.6% underwent maximal supine bicycle exercise with hemodynamic and radionuclide monitoring. Two patterns of exercise response were noted. Group I (n = 7) was characterized by significant (p less than 0.001) increases in stroke work index (SWI) (+52%), stroke volume index (SVI) (+34%), mean arterial pressure (AP) (+23%), and cardiac index (CI) (+119%) and by a decrease in systemic vascular resistance (SVR) (-45% p less than 0.001). In group II (n = 6) there were no significant changes in SWI (-15%), AP (+11%), and SVR (-17%)(; SVI decreased significantly (-14%, p less than 0.05), and the increase in CI, although significant (+27%, p less than 0.01), did not achieve the level of Group I. EF did not change with exercise in either group. There were no significant differences at rest in any of the above variables, and the pulmonary capillary wedge pressures at maximal exercise were similar. We conclude that there are two patterns of exercise response in patients with severe congestive heart failure (CHF) and that these patterns may have important therapeutic and prognostic implications.

Hemodynamic differences between supine and upright exercise in patients with congestive heart failure

Although the differences in hemodynamic responses to supine and upright exercise have been studied in normal subjects and in patients with angina pectoris, no such comparison has been made in patients with congestive heart failure. Many investigators measure exercise hemodynamics in heart failure patients to assess the effect of vasodilator and inotropic drugs. Both modes of exercise have been used and have often yielded differing results. We compared the hemodynamic response to supine and upright exercise in 14 patients with stable, New York Heart Association class III chronic heart failure. During upright exercise, peak heart rate was higher (124 +/- 15 vs 115 +/- 18 beats/min, p less than 0.025) and peak mean arterial pressure was lower (102 +/- 15 vs 95 +/- 17 mm Hg, p less than 0.25), yielding similar double products. Although the peak left ventricular filling pressure was slightly lower during upright exercise (40 +/- 7 vs 35 +/- 10 mm Hg, p less than 0.05), the maximum cardiac and stroke indexes were not significantly different (3.6 +/- 0.8 vs 3.4 +/- 0.8 l/min/m2 and 30 +/- 8 vs 30 +/- 6 ml/m2, upright vs supine exercise). In contrast to these relatively similar hemodynamic responses, exercise capacity was significantly greater during upright exercise (peak work load 336 +/- 84 vs 293 +/- 73 kpm/min, p less than 0.1; maximum oxygen consumption 12.1 +/- 2.4 vs 9.8 +/- 1.9 ml/min/kg, p less than 0.001). We conclude that either exercise method may be used to assess the hemodynamic effects of drugs, but that exercise capacity should be measured in the upright position.

Hydralazine in the long-term treatment of chronic heart failure: lack of difference from placebo

Although hydralazine improves cardiac performance in patients with chronic left ventricular failure, its long-term clinical efficacy has not been established in controlled trials. We carried out a double-blind randomized trial of hydralazine (200 mg daily in 16 patients) versus placebo (16 patients) in patients with class III and IV symptoms while they were taking digitalis and diuretics. Maximal treadmill exercise time was determined prior to and at 4, 10, 18, and 26 weeks of hydralazine or placebo treatment; average follow-up was 20 weeks. We found no change in body weight, clinical class, resting heart rate and blood pressure, or heart size (by chest x-ray examination and echocardiogram) during treatment in either group. The total number of complicating clinical events was insignificantly fewer in the hydralazine treated group (8 vs 13). Control exercise duration in the hydralazine group averaged 259 +/- 21 seconds (SEM), and increased to 347 +/- 35 seconds at 4 weeks (p less than 0.01) and 421 +/- 38 seconds at 26 weeks (p less than 0.001). Exercise duration also increased significantly in the placebo group, from 271 +/- 30 seconds at control to 340 +/- 44 seconds at 4 weeks (p less than 0.02) and 339 +/- 46 seconds at 26 weeks (p less than 0.02). No differences between groups were significant. Left ventricular ejection fraction remained depressed and unchanged in both groups. Thus long-term vasodilator treatment with hydralazine alone is not significantly more effective than placebo in chronic heart failure.

Arterial oxygenation and arterial oxygen transport in chronic myocardial failure at rest, during exercise and after hydralazine treatment

Arterial oxygen transport (cardiac output x arterial oxygen content) may be decreased in heart failure. We studied the determinants of arterial oxygen transport in 15 patients with chronic, severe myocardial failure at rest and during cycle ergometry. During control therapy at rest, arterial oxygen tension was normal (81 +/- 8 mm Hg, mean +/- SD) and increased slightly during exercise (90 +/- 14 mm Hg). During hydralazine therapy at rest, arterial oxygen tension was slightly higher (87 +/- 9 mm Hg) and also increased during exercise (92 +/- 15 mm Hg). Hydralazine did not increase arterial oxygen tension (0.10 greater than p greater than 0.05), but exercise did (p less than 0.02). Arterial oxygen saturation and content were normal and did not change under any condition or treatment. During control therapy at rest, arterial oxygen transport was low (313 +/- 74 ml/min . m2) and remained abnormally low during exercise (434 +/- 124 ml/min . m2). During hydralazine therapy, arterial oxygen transport was higher at rest (457 +/- 100 ml/min . m2) and during exercise (577 +/- 131 ml/min . m2). Hydralazine increased arterial oxygen transport (p less than 0.01) because it increased stroke volume at rest and during exercise, but it did not change arterial oxygenation. Arterial oxygenation is normal in chronic heart failure patients at rest and during exercise. Hydralazine increases cardiac output and arterial oxygen transport without changing arterial oxygenation.

Physiologic and pharmacologic determinants of vasodilator response: a conceptual framework for rational drug therapy for chronic heart failure

This article has attempted to summarize the increasing number of pharmacologic and physiologic variables that are being recognized as important determinants in the response to vasodilator therapy in patients with severe chronic heart failure. It is apparent that a careful consideration of many factors is necessary before proper selection of a specific drug can be made for a specific patient, since not all patients with refractory heart failure demonstrate beneficial hemodynamic and clinical responses to all agents. Each patient presents us with a unique set of physiologic variables; each drug has its own advantages and limitations. Identification of those subgroups of patients most likely to benefit from a specific agent or combination of agents is a major goal for future research. Although a number of hemodynamic variables can be made to improve acutely with a wide variety of vasodilator drugs, well tolerated sustained meaningful clinical benefits are probably observed in relatively few patients. Rational and successful vasodilator therapy is possible only through a highly individualized approach.

Acute and long-term effects of vasodilator therapy on resting and exercise hemodynamics and exercise tolerance

The acute hemodynamic response to vasodilators in patients with chronic heart failure has been well characterized, but less is known about the long-term hemodynamic effects of vasodilator therapy. We measured hemodynamic variables at rest and during upright exercise in 11 patients during the initiation of therapy with oral hydralazine and sublingual isosorbide dinitrate and, in eight of these, after 3 months of continuous treatment. Marked initial increases in resting cardiac output and stroke volume and reductions in wedge pressure were sustained during chronic therapy. Similarly, the early improvement in exercise hemodynamic measurements persisted in most subjects. Exercise tolerance, quantified as the maximum duration of treadmill exercise, increased modestly (7.7 +/- 2.6 to 8.9 +/- 3.3 minutes, 0.05 less than p less than 0.10) after several days on vasodilators and further (10.2 +/- 3.7 minutes, p less than 0.01) during long-term treatment. The acute hemodynamic effects of vasodilator therapy at rest or during exercise did not correlate well with the changes in exercise tolerance. Our findings suggest that the combination of hydralazine and isosorbide dinitrate improves cardiac performance at rest and during exercise in patients with chronic heart failure and that this improvement persists during chronic therapy. In most patients, this hemodynamic improvement is accompanied by greater exercise tolerance.

Effects of isosorbide dinitrate and hydralazine on regional metabolic responses to arm exercise in patients with heart failure

The reduced exercise capacity of patients with heart failure is thought to be due in part to impaired skeletal muscle oxygen delivery. To determine if hydralazine and isosorbide dinitrate improve skeletal muscle oxygen delivery in such patients, the effects of these agents on regional metabolic responses to forearm exercise were examined in 16 patients with heart failure. Arm oxygen extraction and branchial venous lactate concentration were measured at rest and during 3 minutes of rhythmic handgrip and then remeasured after administration of oral hydralazine (nine patients) or sublingual isosorbide dinitrate (nine patients). Hydralazine increased mean (+/- standard deviation) cardiac output at rest from 3.5 +/- 0.5 to 4.9 +/- 1.0 liters/min (p less than 0.01) and decreased arm oxygen extraction from 39 +/- 8 to 33 +/- 10 percent (probability [p] less than 0.01), suggesting improved resting limb oxygen delivery. However, hydralazine did not reduce arm oxygen extraction during exercise (control 63 +/- 4, hydralazine 60 +/- 12 percent; p = not significant [NS]) or venous lactate during exercise (control 16.6 +/- 7.8, hydralazine 17.1 +/- 4.8 mg/100 ml; p = NS). Isosorbide dinitrate increased the cardiac output from 3.6 +/- 0.7 to 4.5 +/- 0.7 liters/min (p less than 0.01) but had no effect on arm oxygen extraction at rest (control 40 +/- 11, isosorbide dinitrate 38 +/- 11 percent; p = NS) and during exercise (control 66 +/- 5, isosorbide dinitrate 64 +/- 8 percent; p = NS) or on venous lactate during exercise (control 17.9 +/- 6.4, isosorbide dinitrate 17.1 +/- 3.9 mg/100 ml; p = NS). These data suggest that hydralazine and isosorbide dinitrate do not improve skeletal muscle oxygen delivery during exercise in patients with heart failure.

Circulatory improvement after hydralazine or isosorbide dinitrate administration in patients with heart failure. Effect on metabolic responses to submaximal exercise

Hydralazine and isosorbide dinitrate can increase the cardiac output during submaximal exercise in patients with heart failure but whether this increase improves oxygen delivery to underperfused exercising muscle is uncertain. To investigate this question, we measured three systemic markers of skeletal muscle oxygen availability--exercise VO2, mixed venous lactate concentration and oxygen debt--during submaximal exercise in 15 patients with heart failure both before after hydralazine (nine patients) or isosorbide dinitrate (eight patients) administration. Hydralazine increased the cardiac output during exercise from 4.9 +/- 1.2 liter/min to 6.5 +/- 1.8 liter/min (p less than 0.01) but had no effect on exercise VO2 (control, 531 +/- 135 ml/min; hydralazine, 489 +/- 102 ml/min), peak lactate concentration (control, 18.3 +/- 4.2 mg/dl; hydralazine, 17.9 +/- 3.6 mg/dl) or oxygen debt (control, 474 +/- 213 ml; hydralazine, 465 +/- 170 ml) (all p greater than 0.10). Isosorbide dinitrate increased the cardiac output during exercise from 4.6 +/- 0.9 liter/min to 5.3 +/- 0.8 liter/min (p less than 0.01) but also did not change exercise VO2 (control, 488 +/- 62 ml/min; isosorbide, 473 +/- 44 ml/min), peak lactate concentration (control, 19.2 +/- 6.0 mg/dl; isosorbide, 21.4 +/- 8.2 mg/dl) or oxygen debt (control, 522 +/- 154 ml; isosorbide, 445 +/- 147 ml) (all p less than 0.10). We conclude that short-term administration of hydralazine or nitrates to patients with heart failure can substantially improve circulatory function during exercise but that this improvement probably does not enhance skeletal muscle nutritional flow.

Vasodilator and inotropic agents in treatment of chronic cardiac failure: clinical experience and response in exercise performance

The sensations of breathlessness and fatigue limit the capacity of patients with chronic congestive cardiac failure (CHF) to participate in physical activities. As a result, patients with CHF gauge quality of life in terms of symptom-free activities they can undertake. Physicians attempt to alleviate these limiting symptoms and increase the exercise capacity of patients with CHF by therapeutic interventions. In recent years a variety of systemic vasodilators and inotropic agents have been introduced to aid digitalis and diuretics in improving cardiac performance in patients with CHF. Although the pumping function of the heart is enhanced at rest, it remains to be determined whether exercise tolerance is also improved. In this paper we review our clinical experience with a number of systemic vasodilators and positive inotropic agents, focusing particular attention on their influence on exercise performance in patients with CHF. This experience includes (1) 28-week double-blind study of hydralazine vs placebo in 19 patients with CHF, (2) 52-week double-blind crossover study of trimazosin (alpha 1 blockade) vs placebo in 27 patients with CHF of varying severity, and (3) open study of amrinone (positive inotropic agent) in 12 patients with CHF.