Are beta-adrenergic-blocking drugs useful in the treatment of dilated cardiomyopathy?

Efficacy of Add-on Therapy with Carvedilol and the Direct Renin Inhibitor Aliskiren for Improving Cardiac Sympathetic Nerve Activity, Cardiac Function, Symptoms, Exercise Capacity and Brain Natriuretic Peptide in Patients with Dilated Cardiomyopathy

Purpose/Method: Aliskiren is a direct renin inhibitor that has been reported to be effective for CHF, but the usefulness of combined therapy with carvedilol and aliskiren has not been reported. Forty-four patients with dilated cardiomyopathy (DCM) were randomized into a group receiving add-on therapy with carvedilol plus aliskiren and another group receiving carvedilol alone for 6 months. Nuclear imagings with ¹²³I-Metaiodobenzylguanidine (MIBG) and ^99mTc-Sestamibi were performed. Exercise capacity using a specific activity scale (SAS) and the New York Heart Association (NYHA) class were evaluated. Cardiac sympathetic nerve activity was evaluated by ¹²³I-MIBG imaging, with the delayed heart-to-mediastinum activity ratio (H/M), delayed total defect score (TDS), and washout rate (WR). Results: Combined add-on therapy with carvedilol and aliskiren improved several parameters much more than carvedilol alone (p<0.05) with respect to TDS, ejection fraction (EF), NYHA, SAS on 6 months and the changes in TDS, EF, end-diastolic volume and brain natriuretic peptide (BNP). Conclusion: Add-on therapy with carvedilol and aliskiren is more effective than carvedilol alone for improving cardiac sympathetic nerve activity, cardiac function, symptoms, exercise capacity, and brain natriuretic peptide in patients with DCM.

Efficacy of amiodarone treatment on cardiac symptom, function, and sympathetic nerve activity in patients with dilated cardiomyopathy: comparison with beta-blocker therapy

BACKGROUND

Amiodarone, which is an antiarrhythmic drug used to treat life-threatening arrhythmias, is effective in patients with chronic heart failure. However, its effectiveness compared with beta-blockers has not yet been reported.

METHODS AND RESULTS

In 30 patients (mean age, 57 +/- 13 years) with dilated cardiomyopathy, we compared 15 patients receiving amiodarone (group A) with 15 patients receiving metoprolol (group B). Before and after 1 year of treatment, cardiac iodine 123 metaiodobenzylguanidine uptake was assessed from the total defect score, heart-to-mediastinum activity ratio based on delayed images, and washout rate. New York Heart Association class and echocardiographic left ventricular ejection fraction were also assessed. In both groups the total defect score decreased (from 25 +/- 11 to 16 +/- 10 in group A, P <.01; from 26 +/- 10 to 18 +/- 11 in group B, P <.01), the heart-to-mediastinum activity ratio increased (from 1.63 +/- 0.16 to 1.81 +/- 0.29 in group A, P <.01; from 1.63 +/- 0.21 to 1.85 +/- 0.3 in group B, P <.01), and the washout rate decreased (from 51% +/- 12% to 38% +/- 14% in group A, P <.01; from 48% +/- 11% to 37% +/- 8% in group B, P <.01). Left ventricular ejection fraction increased (from 30% +/- 9% to 42% +/- 11% in group A, P <.01; from 26% +/- 7% to 46% +/- 16% in group B, P <.01) and New York Heart Association functional class improved (from 3.1 +/- 0.5 to 1.8 +/- 0.7 in group A, P <.01; from 2.9 +/- 0.5 to 1.7 +/- 0.6 in group B, P <.01).

CONCLUSION

Amiodarone treatment can improve cardiac symptom, function, and sympathetic nerve activity, as evaluated by I-123 metaiodobenzylguanidine imaging in patients with dilated cardiomyopathy, which improves to a similar extent with beta-blocker treatment.

Dobutamine gated blood pool scintigraphy predicts the improvement of cardiac sympathetic nerve activity, cardiac function, and symptoms after treatment in patients with dilated cardiomyopathy

BACKGROUND

We evaluated whether dobutamine gated blood pool scintigraphy (DOB-GBP) can predict improvement in cardiac sympathetic nerve activity and cardiac function after beta-blocker therapy in patients with dilated cardiomyopathy (DCM).

METHODS AND RESULTS

Twenty-two patients with DCM underwent DOB-GBP to measure left ventricular ejection fraction (LVEF) at rest, and during 5, 10, and 15 microg/kg/min of dobutamine infusion before therapy. Examinations were performed before and after 1 year of therapy. The heart/mediastinum count (H/M) ratio and total defect score (TDS) were determined for 123I-meta-iodobenzylguanidine images from anterior planar image and single-photon emission CT images. LVEF and left ventricular end-diastolic dimension (LVDd) were determined by echocardiography. After 1 year of treatment, the echocardiographic LVEF improved > 5% in 11 patients (group A), but did not improve in the remaining 11 patients (group B). Before treatment, TDS, H/M, LVEF, and LVDd were similar in both groups. However, there was a greater increase in the LVEF during dobutamine infusion in group A than in group B (21 +/- 8% vs 9 +/- 3%, p < 0.001). If a critical value of 15% for the DeltaLVEF was used to predict the improvement in LVEF after treatment, the sensitivity was 91% and specificity was 82%. The TDS, H/M ratio, LVDd, and New York Heart Association functional class improved in group A to a greater extent than in group B.

CONCLUSIONS

DOB-GBP can be used to predict improved cardiac sympathetic nerve activity, cardiac function, and symptoms after treatment in patients with DCM.

A review of why and how we may use beta-blockers in congestive heart failure

The history of the use of beta-blockers for congestive heart failure, beginning with the innovative seminal study by the Swedish group in 1975 to studies in 1995, is reviewed and shows that almost all trials favored the use of beta-blockers. They tended to demonstrate an increase in ejection fraction, a decrease in left ventricular mass, and in some studies, even a decrease in mortality. Even after the introduction of angiotensin-converting enzyme inhibitors, additional improvement in function and mortality was observed. Patients with nonischemic dilated cardiomyopathy derived more benefit from beta-blockers than did patients with ischemic cardiomyopathy. Least likely to benefit were patients treated for <2 months, patients with alcoholic cardiomyopathy, and those with marked intercellular fibrosis. Although the starting dose of metoprolol, the most common beta-blocker used, may have to be as low as 2.5 mg/d, mortality analysis failed to show a decrease in sudden death unless the dose was raised to about 300 mg/d, a dose at which beta-selectivity is generally not expected to be present. The non-beta-specific bucindolol or carvedilol may ultimately be preferred to metoprolol because they are better tolerated initially due to a slight vasodilatation effect. Initial studies with carvedilol showed remarkable promise in reducing mortality. However, these agents cannot yet be said to have been studied adequately.

Use of iodine-123 metaiodobenzylguanidine myocardial imaging to predict the effectiveness of beta-blocker therapy in patients with dilated cardiomyopathy

It is crucial to predict drug effectiveness in chronic disease, such as dilated cardiomyopathy (DCM), in which the left ventricular (LV) function might be improved by beta-blocker therapy. As the functional improvement effected by beta-blocker therapy takes more than 2 months, we investigated whether iodine-123 metaiodobenzylguanidine (123I-MIBG) imaging could be used to predict drug effectiveness. We studied 13 patients (11 men and two women; mean age, 43+/-13 years) with DCM and seven normal subjects (six men and one woman; mean age, 48+/-16 years). We obtained myocardial single-photon emission tomography (SPET) images 15 min and 4 h after administration of 123I-MIBG (111 MBq). Studies were performed in the patients with DCM before and 1 and 3 months after the administration of metoprolol and in the normal subjects. We calculated the regional 123I-MIBG washout rate (r-WR) in the SPET image, and the global 123I-MIBG washout rate (g-WR) and heart-mediastinum activity ratio (H/M) using the anterior planar image. We classified patients into those showing a >/=5% increase in LV ejection fraction (LVEF) at 3 months compared with LVEF values before the treatment (group I, n=7) and those showing a <5% increase in LVEF (group II, n=6). In group I, the r-WR values at pretreatment and at 1 month and 3 months of treatment, respectively, were 36%+/-19%, 29%+/-14%* and 25%+/-13%* in the anterior segment, 39%+/-17%, 33%+/- 17%** and 28%+/-17%* in the lateral segment, 36%+/- 16%, 31%+/-14%* and 22%+/-12%** in the septal segment and 40%+/-11%, 37%+/-19% and 31%+/-18%* in the inferior segment; the g-WR was 45%+/-11%, 43%+/-10% and 34%+/-9%*, respectively (* P<0.05, ** P<0.01 vs pretreatment). In group II, there were no significant changes in regional or global parameters during the 3-month period. In normal subjects, the r-WR values in each of the anterior, lateral, septal and inferior segments were significantly lower than those in groups I and II. These values were 18%+/-9%, 18%+/-15%, 20%+/-12% and 21%+/-15%, respectively. This study demonstrated that with regional assessment 123I-MIBG SPET imaging can be used to predict the functional improvement of LVEF at 1 month of beta-blocker therapy in patients with DCM.

Hemodynamic predictors of early intolerance and long-term effects of propranolol in dilated cardiomyopathy

BACKGROUND

Fifty-six patients with dilated cardiomyopathy (DCM) (aged 14-68 years) and background therapy of angiotensin-converting enzyme inhibitors, diuretics, and digoxin were given an initial challenge of propranolol in gradually increasing doses. These patients were studied noninvasively and hemodynamically and subjected to right ventricle biopsy.

METHODS AND RESULTS

Forty-four patients tolerated propranolol and received the drug for 6 months; 12 patients deteriorated after starting the drug with worsening of congestive heart failure and/or hypotension. The patients who did not tolerate propranolol had higher left ventricular end-diastolic dimension (73 +/- 8 vs 66 +/- 8 mm, P < .05), and severe mitral regurgitation was more common. Hemodynamically these patients had higher heart rate, right ventricular end-diastolic pressure, mean pulmonary artery pressure, mean pulmonary artery wedge pressure, and left ventricular end-diastolic pressure (102 +/- 16 vs 89 +/- 12 beats/min, 15 +/- 7 vs 9 +/- 4, 39 +/- 16 vs 31 +/- 12, 28 +/- 8 vs 21 +/- 8, 28 +/- 8 vs 22 +/- 8 mmHg, respectively, P < .01). These patients had a significantly lower cardiac index (1.9 +/- 0.6 vs 2.5 +/- 0.6 L/min/m2, P < .01). Forty patients completed 6 months follow-up evaluation and were further subjected to repeat noninvasive and hemodynamic study. There was a significant improvement in New York Heart Association class, cardiothoracic ratio, and left ventricular end-diastolic dimension (68% vs 62%, 66 +/- 8 vs 62 +/- 7 mm, respectively, P < .01), while the ejection fraction (EF) rose from 23 to 35% (P < .001). Hemodynamically, there was a significant decrease in heart rate, right ventricular end-diastolic pressure, mean pulmonary artery pressure, mean pulmonary artery wedge pressure, and left ventricular end-diastolic pressure (91 +/- 14 vs 71 +/- 5 beats/min, 9 +/- 4 vs 5 +/- 3, 32 +/- 11 vs 22 +/- 7, 25 +/- 9 vs 17 +/- 8, 21 +/- 7 vs 14 +/- 4 mmHg, P < .05). The cardiac index rose from 2.3 +/- 0.6 to 3.2 +/- 0.7 L/min/m2 (P < .01).

CONCLUSIONS

Propranolol in dilated cardiomyopathy is associated with significant intolerance. Those who tolerate propranolol seem to have long-term beneficial effects. This study is limited as it is uncontrolled and nonrandomized.

Benefit of converting enzyme inhibition on left ventricular volumes and ejection fraction in patients receiving beta-blockade after myocardial infarction. CONSENSUS II multiecho study group

Beta-blockers reduce infarct size and improve survival after acute myocardial infarction (MI). Post-MI angiotensin-converting enzyme inhibition also improves survival and may attenuate left ventricular (LV) dilatation. We evaluated the effect of early enalapril treatment on LV volumes and ejection fraction (EF) in patients on concomitant beta-blockade after MI. Intravenous enalaprilat or placebo was administered <24 hours after MI and was continued orally for 6 months. LV volumes were assessed by echocardiography 3 +/- 2 days, 1 and 6 months after MI. Change in LV diastolic volume during the first month was attenuated with enalapril (2.7 vs placebo 6.5 ml/m2 change; p < 0.05), and significantly lower LV diastolic and systolic volumes were observed with enalapril treatment compared with placebo at 1 month (enalapril 47.21 23.9 vs placebo 53.1/29.2 ml/m2; p < 0.05) and at 6 months (enalapril 47.9/24.8 vs placebo 53.8/29.6 ml/m2; p < 0.05). EF was also significantly higher 1 month after MI in these patients (enalapril 50.4% vs placebo 46.4%; p < 0.05). Our date demonstrate that early enalapril treatment attenuates LV volume expansion and maintains lower LV volumes and higher EF in patients receiving concurrent beta-blockade after MI. A possible additive effect of combined therapy should be evaluated prospectively.

Beneficial effects of metoprolol in heart failure associated with coronary artery disease: a randomized trial

OBJECTIVES

This clinical trial was performed to determine the safety and clinical impact of titrated metoprolol therapy in patients with heart failure, documented coronary artery disease and a low ejection fraction.

BACKGROUND

Despite known cardiodepressant effects, long-term use of beta-adrenergic antagonists appears to be beneficial in patients with idiopathic dilated cardiomyopathy. However, this therapy has not been critically evaluated in patients with heart failure and coronary artery disease.

METHODS

In 50 patients with heart failure, known coronary artery disease and an ejection fraction < or = 0.40, we examined the impact of metoprolol therapy in a 6-month double-blind, placebo-controlled randomized trial, assessing the frequency of heart failure exacerbations and changes in symptoms (New York Heart Association functional class), ejection fraction and exercise duration. Placebo-treated patients who completed 6-month follow-up studies then underwent a trial with metoprolol therapy (crossover group).

RESULTS

Metoprolol was titrated to a mean maximal dose of 87 mg/day (range 25 to 100) without serious adverse reactions. During double-blind therapy, use of a beta-blocker was associated with a significant reduction in the number of hospital admissions (4% vs. 32%, p < 0.05), overall improved functional class (p = 0.02), increased ejection fraction (4 +/- 7% [mean +/- SD] compared with 0 +/- 6%, p < 0.05) and a greater increase in exercise duration (193 +/- 276 vs. 38 +/- 213 s with placebo, p < 0.01). Crossover outcome paralleled the favorable impact seen during randomized metoprolol therapy.

CONCLUSIONS

Cautious use of titrated metoprolol appears to be safe and beneficial when added to standard heart failure therapy in patients with dilated cardiomyopathy associated with coronary artery disease.

Effect of metoprolol on the beta-adrenoceptor density of lymphocytes in patients with dilated cardiomyopathy

We investigated the effect of the beta 1-selective blocker metoprolol on the beta-adrenergic receptor density of circulating lymphocytes in patients with dilated cardiomyopathy. Nine men in New York Heart Association functional classes II (six patients) and III were given metoprolol for 6 months (mean dose 45.6 +/- 18.1 mg). Their cardiac function was assessed by echocardiography. Although there was no difference in the heart rate or pressure rate products, the end-systolic and end-diastolic dimensions significantly decreased in six patients after metoprolol treatment. The ejection fraction, fractional shortening, and mean left ventricular circumferential shortening were significantly increased after the treatment. beta-Adrenoceptor densities of lymphocytes, examined by iodine 125-labeled iodocyanopindolol, were reduced in patients at entry but recovered to normal levels after the metoprolol treatment. The dissociation constants did not differ at any stage of the disease. The relationship between beta-adrenoceptor densities in lymphocytes and echocardiographic parameters showed a positive correlation with the plasma norepinephrine concentration. This study thus provides evidence that long-term metoprolol therapy for dilated cardiomyopathy is associated with beta-receptor up-regulation, and the restoration of myocardial beta-receptor density may be associated with the improved cardiac function as determined by echocardiography.

The paradox of beta-adrenergic blockade for the management of congestive heart failure

PURPOSE

To review the current data regarding the use of beta-adrenergic blockers for the treatment of congestive heart failure.

MATERIAL AND METHODS

Relevant studies published between 1975 and 1991 were reviewed. Key data from each study were extracted. The significance of conclusions reached by each author(s) was identified.

RESULTS

beta-adrenergic blockade, although still considered an investigational therapy for the treatment of congestive heart failure, has been proven in several studies to improve ventricular function, including myocardial contractility and relaxation. In addition, since beta-blockade up-regulates myocardial beta-receptors, the myocardium becomes more responsive to graded doses of beta-agonists. Speculation regarding the possible mechanisms of these effects is presented. In addition, since beta-blockers have been shown to reduce neurohormonal activation, they may have a beneficial effect on survival. Although small pilot studies or subgroup analysis of larger studies suggest beta-blockade therapy improves survival in heart failure, this has yet to be proven. Large prospective trials are warranted to study this issue.

CONCLUSIONS

As current data suggest, beta-blockers improve ventricular function and reduce neurohormonal activation in heart failure. beta-blockers should be considered as adjunctive therapy in patients with congestive heart failure. In addition, future studies are warranted to better elucidate their effects on ventricular function and survival.

Comparative hemodynamic effects of mexiletine and quinidine in patients with severe left ventricular dysfunction

Mexiletine and quinidine are often administered to patients with severe congestive heart failure, but their hemodynamic effects have not been adequately studied in these individuals. In a randomized, crossover study, the hemodynamic responses to single oral doses of quinidine (600 mg) and mexiletine (400 mg) were compared in 20 patients with marked left ventricular dysfunction. Quinidine predominantly caused vasodilation, with mean arterial, left ventricular filling, and right atrial pressures all decreasing (-7 +/- 2, -2.3 +/- 1.0, and -1.1 +/- 0.5 mm Hg, respectively) and the systemic vascular resistance also declining (-308 +/- 84 dynes.sec.cm5). In contrast, the systemic vascular resistance increased (314 +/- 84 dynes.sec.cm-5) and the mean arterial, left ventricular filling, and right atrial pressures also increased (+2 +/- 2, +6.1 +/- 1.8, and +1.8 +/- 0.6 mm Hg, respectively) after mexiletine. Cardiac performance declined with mexiletine (cardiac and stroke work indexes decreasing -0.3 +/- 0.1 L/min/m2 and -5 +/- 1 gm.m/m2, respectively), but there was no significant change in cardiac or stroke work indexes with quinidine (+0.1 L/min/m2 and -0.3 +/- 0.9 gm.m/m2, respectively). The response to the two agents significantly differed for all parameters measured (p less than 0.005). These hemodynamic changes were accompanied by clinical effects. Mexiletine induced increased dyspnea in five patients and quinidine led to symptomatic hypotension in two patients. Plasma concentrations of mexiletine and serum concentrations of quinidine were within or below the therapeutic range in all patients. In conclusion, mexiletine and quinidine exert different hemodynamic effects when given to patients with severe congestive heart failure.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of medical therapy on survival of patients with dilated cardiomyopathy

Few studies have been conducted that focus on survival as the end point of medical therapy of CHF. No vigorous studies have been conducted in dogs. It is generally accepted that diuretic therapy is an essential component of the therapy of CHF in cardiomyopathic dogs. Significant symptomatic improvement is afforded by diuretics, and acute death may be prevented. In this context diuretics can be said to improve survival. However, diuretics do not alter the natural progression of cardiomyopathy and in this context do not favorably influence long-term survival. Digitalis glycosides have been shown in humans to improve various parameters of CHF in a subset of patients with either atrial fibrillation or third heart sounds. In dogs, these gallop heart rhythms due to third heart sounds are usually associated with myocardial failure due to dilated cardiomyopathy. In spite of symptomatic improvement, no study has demonstrated an unequivocal favorable effect of digoxin on survival of patients with dilated cardiomyopathy. Likewise, there is no convincing evidence of an adverse effect on survival. Newer, powerful inotropes, such as milrinone, often demonstrate impressive short-term improvements in left ventricular function, clinical signs, and exercise tolerance in patients with CHF. However, their long-term benefits are much less impressive, they are arrhythmogenic, and they have not been shown to prolong survival. In fact, long-term milrinone therapy in humans has had an unfavorable influence on mortality. Vasodilators offer the potential advantage of increasing left ventricular performance without an associated increase in myocardial oxygen demand and cardiac rhythm disturbances. The only vigorous survival study that unequivocally demonstrated improved survival of patients with advanced CHF due to myocardial failure, including dilated cardiomyopathy, was the Consensus Trial. Survival of patients receiving enalapril was significantly better than those receiving placebo. In fact, the trial was stopped prematurely by the ethical review committee when it became obvious that the results favored the enalapril group. Although the use of beta-adrenergic blocking drugs in cardiomyopathic patients with CHF is controversial and associated with a risk of short-term deterioration of left ventricular function, their use in human medicine is gaining acceptance. Although hemodynamic and clinical evidence of improvement has been demonstrated along with withdrawal-associated deterioration, the only study purporting a beneficial effect on survival used retrospective controls.(ABSTRACT TRUNCATED AT 400 WORDS)

Around the beta-blockers, one more time

We review the pharmacology, pharmacokinetics, and relative costs of beta-blockers, as well as indications for and therapeutic controversies surrounding their use. It is hoped that this discussion will assist clinicians in making informed decisions when choosing a drug for a hospital formulary or a particular patient. Beta-blockers are indicated for a variety of noncardiovascular and cardiovascular conditions, including hypertension, ischemic heart disease, arrhythmias, and prophylaxis of myocardial infarction (MI). These agents compete with catecholamines at beta-adrenoreceptors. They have different ancillary properties, including intrinsic sympathomimetic activity (ISA), cardioselectivity, and membrane stabilizing-activity, and vary in their duration of action, route of elimination, and lipophilicity. Beta-blocking agents decrease oxygen demand by exerting a negative inotropic and chronotropic effect. They also reduce blood pressure and possess antiarrhythmic effects. Beta-blockers penetrate the central nervous system (CNS) to different degrees and can cause a wide variety of CNS adverse effects. Nonselective beta-blockers have been noted to slightly reduce renal blood flow. Nadolol is an exception in that either no change, or even a small increase in renal blood flow, is observed upon initiation of therapy. Beta-blockers also act on the pulmonary bed by preventing beta 2-mediated bronchodilation, thereby exacerbating bronchospastic disease in some patients. Beta-adrenergic blocking agents can potentiate both hypoglycemia and hyperglycemia in diabetic patients. Their effects on total peripheral resistance (TPR) are controversial. Initially it appears that beta-blockade increases TPR. After chronic therapy, however, TPR decreases to or below baseline values. These agents appear to be equally efficacious in the treatment of hypertension, arrhythmias, and ischemic heart disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Beta-blocker treatment of dilated cardiomyopathy. Beneficial effect of carteolol in mice

BACKGROUND

The effects of carteolol, a nonselective beta-adrenergic receptor blocker with intrinsic sympathomimetic activity, were compared with those of metoprolol in a murine model of viral myocarditis and dilated cardiomyopathy caused by encephalomyocarditis virus.

METHODS AND RESULTS

In the acute experiment, BALB/c and DBA/2 mice were inoculated with encephalomyocarditis virus. BALB/c mice were then given carteolol at 1 (n = 10), 10 (n = 10), 30 (n = 11), or 100 mg/kg (n = 9) daily, and DBA/2 mice were given carteolol at 1 (n = 9) or 10 mg/kg (n = 9) daily starting the day of inoculation. Controls were given distilled water (n = 23 for BALB/c mice and n = 8 for DBA/2 mice). BALB/c mice were killed on day 7, and DBA/2 mice were killed on day 14. In the subacute experiment, DBA/2 mice were inoculated with the virus and then given carteolol at 1 (n = 12) or 10 mg/kg (n = 16), or distilled water (n = 27) daily, starting on day 14. Mice were killed on day 28. Virus replication, murine survival, heart weight to body weight ratio, and histopathological findings were similar in each group in the acute and subacute experiments. In the chronic experiment, DBA/2 mice were inoculated with the virus and were then given carteolol at 1 (n = 13) or 10 mg/kg (n = 9), metoprolol at 30 mg/kg (n = 9), or distilled water (n = 31) daily, starting on day 14. Mice were killed on day 104. Heart weight to body weight ratio and histopathological scores were significantly lower in mice given carteolol than in the infected control group. Furthermore, left ventricular cavity dimension, left ventricular wall thickness, and myocardial fiber diameter of the left ventricle were significantly reduced in mice given carteolol compared with the control group. Metoprolol did not cause any significant changes compared with the control group.

CONCLUSIONS

This study suggests that carteolol prevents the development of myocardial lesions similar to those in dilated cardiomyopathy after myocarditis in the chronic stage.

Long-term (2 year) beneficial effects of beta-adrenergic blockade with bucindolol in patients with idiopathic dilated cardiomyopathy

Beta-adrenergic blockade represents a promising therapeutic approach to idiopathic dilated cardiomyopathy. Bucindolol, a new beta-blocker, showed favorable effects in a short-term (3 month) trial in idiopathic dilated cardiomyopathy. To assess long-term response, 20 study patients (7 of 9 patients previously assigned to the placebo group and 13 of 14 patients previously assigned to bucindolol therapy) received long-term bucindolol therapy and were followed up for a mean of 23 +/- 4 months (range 17 to 30). The mean patient age was 49 years (range 29 to 66) and the median duration of disease was 11 months (range 1 to 190). Ten patients were in functional class II and 10 were in class III; 15 patients were men. At the end of the common follow-up time, all 20 patients were alive, 17 continued to receive bucindolol (mean dose 176 mg/day, range 25 to 200), and 2 underwent cardiac transplantation. Left ventricular ejection fraction increased from a baseline value of 25 +/- 8% to 35 +/- 13% (n = 19 pairs, p less than 0.001). Functional class improved in 12, was unchanged in 5 and deteriorated in 3 (p = 0.056). Exercise time was maintained (9.4 +/- 3.1 versus 9.1 +/- 3.5 min, n = 19, p = NS), as was maximal oxygen uptake (19.2 +/- 4.9 versus 18.8 +/- 5.7 ml/kg per min, n = 19, p = NS). Thus, long-term bucindolol therapy leads to substantial increases in ejection fraction and to improved functional class while stable exercise performance is maintained.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of beta-adrenergic blockade in dilated cardiomyopathy--a questionnaire study in Japan

The effect of beta-blockade in dilated cardiomyopathy was studied by a questionnaire survey. Thirty-three cases were monitored in whom metoprolol (22 patients, 35.9 +/- 20.4 mg, mean +/- SD), propranolol (four patients, 26.3 +/- 7.5 mg), or other beta-blockers (seven patients) were administered. Four patients died, but no direct relationship was found between administration of beta-blocker and death. The NYHA functional class improved significantly. The mean heart rate decreased from 96/min to 77/min (P less than 0.01). The mean cardiothoracic ratio decreased from 55.6% to 52.1% (P less than 0.01). The mean ejection fraction of the left ventricle measured by echocardiogram increased from 30.4% to 36.9% (P less than 0.01). Exercise tolerance in the treadmill test improved significantly. There was no change in blood pressure, nor were there arrhythmias seen on Holter electrocardiograms. In two patients, congestive heart failure deteriorated after administration of beta-blockers. It is concluded that beta-adrenergic blockade has a beneficial effect in most of the patients with dilated cardiomyopathy.

Therapy of idiopathic dilated cardiomyopathy with chronic beta-adrenergic blockade

Conventional therapy of patients with idiopathic dilated cardiomyopathy is currently directed at the control of heart failure. However, the morbidity and mortality of idiopathic dilated cardiomyopathy remains very high despite such interventions. One promising new approach to therapy of idiopathic dilated cardiomyopathy is beta-blockade. The potential mechanisms for benefit from beta-blockade include protection from catecholamine cardiotoxicity, upregulation of myocardial beta-adrenergic receptors, reduction in sudden death, reduction in heart rate, improved ventricular diastolic function, and reduction in afterload. Several reports have suggested that long-term beta-blockade may improve hemodynamic function, clinical symptoms, and survival in patients with idiopathic dilated cardiomyopathy. However, data from controlled trials are limited and some reports have been negative. This paper will summarize the rationale for the use of beta-blocker therapy in idiopathic dilated cardiomyopathy and review the clinical experience with this therapy.

Detrimental effects of beta-adrenergic stimulation on beta-adrenoceptors and microtubules in the heart

Increased plasma catecholamines - in particular, excessive beta-adrenoceptor activation in chronic heart failure - may easily desensitize the beta-adrenoceptors as well as the postreceptor signal transductions. Since these detrimental changes in the failing heart could be reversible, administration of low-dose beta-blocker, which minimizes the negative inotropic effects, may be effective in attenuating the harmful effects of sympathetic nerve activation. Beta-adrenoceptor stimulation may also produce microtubule disruptions of the cell either through direct action or through an increase in heart rate. Treatment with beta-blockers could attenuate Ca overload by slowing the heart rate and may be useful as a protection from the structural disintegration of the cell. Thus, to clarify the underlying mechanisms of beta-blocker therapy for chronic heart failure, we have to consider not only to the functional aspects but also to the structural changes of the cells.

Oral metoprolol therapy in dilated cardiomyopathy: hemodynamic evidence for improved diastolic function accompanying amelioration of symptoms

Twenty patients with dilated cardiomyopathy (11 males and 9 females) aged from 14 to 54 (37.3 +/- 10.5) years were treated orally with metoprolol (dose 37.5 mg-100 mg/day, mean 91 +/- 18.6 mg/day) after a baseline hemodynamic study. On follow-up, all patients showed improvement in symptomatic status by at least one NYHA class within 2 to 4 weeks of the initiation of therapy. Repeat right heart study and left ventricular angiography (venous digital subtraction angiography) afer 3 to 6 months of treatment in 10 patients showed a fall in the mean pulmonary arterial wedge pressure from 24.4 +/- 9.6 to 12.8 +/- 7.7 mm Hg (P = 0.025), right ventricular end-diastolic pressure from 8.8 +/- 4.7 mm Hg to 4.5 +/- 1.9 mm Hg (P = 0.025) and mean pulmonary arterial pressure from 34.2 +/- 12.4 mm Hg to 25.9 +/- 10.9 mm Hg (P less than 0.01). There was no significant change in the left ventricular ejection fraction (18.7 +/- 1.6% vs. 22 +/- 0.48%, P = NS) or cardiac index (2.2 +/- 0.48 l/m/m2 to 2.12 +/- 0.68 l/m/m2, P = NS). These hemodynamic results indicate that the improvement in symptoms and congestive cardiac failure produced by treatment with metoprolol in patients having dilated cardiomyopathy is related to improvement in diastolic function of the myocardium.

Can heart failure be prevented, delayed, or reversed?

A review of the clinical course of chronic heart failure demonstrates that current outcomes remain highly unsatisfactory both in mortality and perhaps more important in morbidity. The extraordinary satisfactory functional responses seen in patients who undergo cardiac transplantation clearly identify the primary cause as the status of the heart itself, whatever the pathophysiologic adjustments of the neuroendocrine system, and interventions of the wide variety of drugs. Since donor hearts are unlikely to be available even from younger sufferers of these clinical syndromes, prevention must be the hallmark. Protection of the viability of myocytes, such as in acute myocarditis and acute infarction, is essential. Myocardial collagen undergoes continual synthesis, and production is greatly stimulated in the presence of hypertrophy caused by increased wall stress. It is possible that excess collagen is intimately involved with diastolic ventricular dysfunction, but that this may be a reversible process if the collagen-producing stimulus is removed. Thus reduction in wall stress and reversibility of ventricular hypertrophy appear to be promising directions. However, to limit the catastrophic effects of chronic heart failure, early recognition of the precursors of these syndromes, prevention of progression, and surgical intervention in valvular heart disease at an optimal point in time are essential.

Effects of metoprolol on rest and exercise cardiac function and plasma catecholamines in chronic congestive heart failure secondary to ischemic or idiopathic cardiomyopathy

To define the effects of 2 months of metoprolol therapy on cardiac function, aerobic performance and sympathetic nervous system activity, metoprolol (75 to 100 mg/day) was administered to 10 patients with chronic congestive heart failure (CHF). Metoprolol was discontinued in 2 patients because of worsening CHF. In the remaining 8 patients, peak oxygen uptake increased significantly (14.8 +/- 3.0 to 16.1 +/- 2.5 ml/kg/min, p less than 0.05) as did the oxygen pulse (9.0 +/- 2.2 to 12.6 +/- 1.8 ml/beat, p less than 0.02). Resting heart rate (87 +/- 18 to 62 +/- 9 beats/min, p less than 0.05) and peak exercise heart rate (133 +/- 13 to 105 +/- 30 beats/min, p less than 0.02) were both reduced. Mean resting ejection fraction increased from 0.15 +/- 0.06 to 0.25 +/- 0.11 and peak exercise ejection fraction also tended to increase (0.19 +/- 0.11 to 0.28 +/- 0.15, difference not significant). Both resting plasma norepinephrine (613 +/- 706 to 303 +/- 142 pg/ml, p less than 0.05) and epinephrine (71 +/- 50 to 40 +/- 21 pg/ml, p less than 0.05) were reduced. Circulating lymphocyte beta-adrenergic receptor number was unchanged (1,334 +/- 292 to 1,344 +/- 456 receptors/cell, difference not significant). It is concluded that metoprolol therapy is associated with improvements in rest and exercise ventricular performance and maximal aerobic capacity. These improvements are associated with a decline in resting sympathetic nervous system activity.

Hemodynamic effects of nebivolol at rest and on exertion in patients with heart failure

Nebivolol is a novel B-1-adrenoceptor-blocking drug with an unusual hemodynamic profile unlike classical B-blockers. In dogs and in healthy volunteers it decreases blood pressure and heart rate but improves left ventricular function. The authors studied 10 male patients with coronary artery disease and heart failure (ejection fraction mean = 46%). A Swan-Ganz catheter was placed into the pulmonary artery, and the mean blood pressure, the heart rate, the pulmonary artery pressure, the pulmonary wedge pressure, the right atrial pressure, the cardiac output, and the stroke volume were measured at rest and on exertion before and after seven days' treatment with oral nebivolol (5 mg/day). While the blood pressure and the heart rate decreased significantly, the pulmonary artery and wedge pressures, as well as the right atrial pressure and the cardiac output, did not change during treatment. The stroke volume increased significantly. The maintained cardiac output cannot be explained by any changes in preload or afterload; instead a positive inotropic mechanism must be assumed. Unlike other B-blockers it seems to be possible to treat patients with heart failure with nebivolol without causing the hemodynamic situation to deteriorate.

Usefulness of bucindolol in congestive heart failure

The sympathetic hyperactivity of congestive heart failure (CHF) may worsen cardiovascular function by down-regulation of myocardial beta-receptors. For this reason, beta blockade is proposed to be useful in CHF. Bucindolol is a new beta blocker that has intrinsic nonadrenergically-mediated vasodilation and may be valuable in treatment of CHF. To test this, 19 patients with CHF were randomized in a double-blind protocol to 3 months of treatment with bucindolol (n = 12) or placebo (n = 7). Significant improvement was seen in the bucindolol group using invasive and noninvasive tests; treadmill time increased from 445 to 530 seconds (p = 0.04), Minnesota Living With Heart Failure Questionnaire score improved from 61 to 40 (p = 0.0001), cardiac output increased from 4.0 to 4.7 (p = 0.02), and systemic vascular resistance decreased from 1,888 to 1,481 (p = 0.04). Also, peak exercise heart rate and pulmonary capillary wedge pressure decreased significantly with treatment. There were no changes in the placebo group. We conclude that bucindolol may be an effective treatment for CHF when administered chronically and that its nonadrenergic vasodilation may be an important feature.

Effect of beta-adrenergic blockade on myocardial function and energetics in congestive heart failure. Improvements in hemodynamic, contractile, and diastolic performance with bucindolol

The hemodynamic effects of beta-adrenergic blockade with bucindolol, a nonselective beta-antagonist with mild vasodilatory properties, were studied in patients with congestive heart failure. Fifteen patients (New York Heart Association class I-IV) underwent cardiac catheterization before and after 3 months of oral therapy with bucindolol. The left ventricular ejection fraction increased from 0.23 +/- 0.12 to 0.29 +/- 0.14 (p = 0.007), and end-systolic elastance, a relatively load-independent determinant of contractility, increased from 0.60 +/- 0.40 to 1.11 +/- 0.45 mm Hg/ml (p = 0.0049). Both left ventricular stroke work index (34 +/- 13 to 47 +/- 19 g-m/m2, p = 0.0059) and minute work (5.5 +/- 2.2 to 7.0 +/- 2.6 kg-m/min, p = 0.0096) increased despite reductions in left ventricular end-diastolic pressure (19 +/- 8 to 15 +/- 5 mm Hg, p = 0.021). There was an upward shift in the peak + dP/dtmax-end-diastolic volume relation (p = 0.0005). These data demonstrate improvements in myocardial contractility after beta-adrenergic blockade with bucindolol. At a matched paced heart rate of 98 +/- 15 min-1, the time constant of left ventricular isovolumic relaxation was significantly reduced by bucindolol therapy (92 +/- 17 versus 73 +/- 11 msec, p = 0.0013), and the relation of the time constant to end-systolic pressure was shifted downward (p = 0.014) with therapy. The slope of the logarithm left ventricular end-diastolic pressure-end-diastolic volume relation was unchanged (p = 0.51) after bucindolol. These data suggest that chronic beta-adrenergic blockade with bucindolol improves diastolic relaxation but does not alter myocardial chamber stiffness. Myocardial oxygen extraction, consumption, and efficiency were unchanged despite improvement in contractile function and mechanical work. Thus, in patients with congestive heart failure, chronic beta-adrenergic blockade with bucindolol significantly improves myocardial contractility and minute work, yet it does not do so at the expense of myocardial oxygen consumption. Additionally, bucindolol improves myocardial relaxation but does not affect chamber stiffness.

Atenolol in dilated cardiomyopathy: a clinical instrumental study

The usefulness of beta blockers in the treatment of congestive heart failure has been questioned. We selected 11 patients, mean age 47.1 +/- 13.8, affected by dilated cardiomyopathy in NYHA class III, who had been taking digoxin and diuretics for a long time. Atenolol 50 mg was added to conventional therapy. Both before and 3 months after treatment a clinical evaluation, chest x-ray, an exercise test, and an echocardiogram were performed. We observed an improvement of NYHA class in five patients. However, the exercise test showed no improvement: 2310 +/- 1299 vs. 2902 +/- 983 total kgm (ns). The echocardiogram showed improvements of the end-systolic diameter (from 6.3 +/- 1 cm to 5.9 +/- 0.8 cm; p less than 0.02), the fractional shortening (from 13.6 +/- 6.3% to 15.2 +/- 5.6%; p less than 0.05) the radius/thickness ratio (from 4.14 +/- 0.5 to 3.5 +/- 0.5; p less than 0.05), and the wall stress (from 208.4 +/- 49 g/cm2 to 163.5 +/- 41 g/cm2; p less than 0.02). The inotropic state index did not show any changes. We conclude that in some patients with dilated cardiomyopathy beta blockers may improve the clinical status and left ventricular performance.

Evidence against spare or uncoupled beta-adrenoceptors in the human heart

It is well established that increasing degrees of heart failure are accompanied by a reduced density of myocardial beta-adrenoceptors. It is unclear, however, whether all beta-adrenoceptors in the cardiac cell membrane are coupled to the effector system or whether "spare receptors" or "uncoupled" beta-adrenoceptors also exist. To investigate this, we measured the density of beta-adrenoceptors and the positive inotropic response to isoprenaline in preparations from the same human hearts. The myocardium from nonfailing hearts had significantly (p less than 0.01) higher numbers of beta-adrenoceptors (104 +/- 7 fmol/mg protein) compared with tissue from moderately (mitral valve disease, New York Heart Association [NYHA] class II to III, 60 +/- 2.8 fmol/mg protein) and terminally (dilated cardiomyopathy, NYHA class IV, 35 +/- 2.7 fmol/mg protein) failing human hearts. The KD values of the drug-receptor complexes did not differ within the different patient groups. There was a linear relationship (r = 0.97) between the beta-adrenoceptor density measured and the maximally obtainable positive inotropic effect elicited by isoprenaline in the three groups tested. Thus there seem to be no spare beta-adrenoceptors, that is, receptors not required for the production of the maximal inotropic response in the left ventricular human myocardium, and there are no uncoupled beta-adrenoceptors. The beta-adrenoceptors associated with the plasma membrane (marker: 3H-ouabain binding sites) remained functionally active. In addition, these results indicate that either there is no amplifier system behind the receptor level or it remains unchanged in the failing left ventricular human myocardium under the conditions tested.

Ventricular arrhythmias in congestive heart failure

Despite advances in the treatment of congestive heart failure (CHF), the mortality rate continues to be high. A large number of the deaths are sudden, presumably due to ventricular arrhythmias. Complex ventricular arrhythmias are recorded in as many as 80% of patients with CHF, with nonsustained ventricular tachycardia occurring in 40%. The latter appears to be an independent predictor of mortality. Chronic structural abnormalities responsible for CHF may be the basis for the capability of a ventricle to support life-threatening arrhythmias, which are triggered by premature ventricular contractions. The pathogenesis of arrhythmias is multifactorial. Electrolyte abnormalities, ischemia, catecholamines, inotropic and antiarrhythmic drugs may worsen arrhythmias and increase susceptibility of a ventricle to sustained arrhythmias. Beta-adrenergic blockers and angiotensin-converting enzyme inhibitors have a beneficial effect. The role of various drugs in the pathogenesis and treatment of ventricular arrhythmias is discussed. The efficacy of antiarrhythmic therapy targeted to asymptomatic nonsustained ventricular tachycardia, in order to prevent sudden death, is controversial. Pharmacotherapy guided by electrophysiologic testing is the treatment of choice for patients who have manifest sustained ventricular tachycardia, but patients resuscitated from ventricular fibrillation may require automatic implantable cardioverter defibrillator.

Hemodynamic effects of dilevalol in patients with systemic hypertension and left ventricular dysfunction

Hemodynamic and left ventricular function parameters were measured in patients with mild to moderate hypertension and compromised left ventricular function who were given dilevalol, an antihypertensive agent with selective beta 2-agonism and nonselective beta-antagonist activity. After a 2- to 3-week placebo washout period, 9 patients were given dilevalol titrated upward from 100 to 600 mg twice daily over a 7-week period to achieve a supine diastolic blood pressure of less than 90 mm Hg with a decrease of greater than or equal to 10 mm Hg from baseline. Multigated radionuclide ventriculography and systolic and diastolic time intervals were performed after the pretreatment placebo washout, at the end of 2 weeks' maintenance dosing, and after a 7- to 10-day post-treatment discontinuation and placebo washout period. At an average daily dose of dilevalol, 444 mg, heart rate at rest decreased significantly (p less than 0.01) during treatment and increased during post-treatment placebo. Systolic and diastolic blood pressures at rest decreased significantly (p less than 0.01) during treatment and increased during post-treatment placebo. At maximal exercise, changes in blood pressure and heart rate were significantly blunted (p less than 0.05) during treatment. Ejection fraction at rest increased significantly (p less than 0.01) during treatment, with no significant change occurring during exercise, and decreased during post-treatment placebo. Preejection period decreased significantly during treatment (p less than 0.005) and increased during post-treatment placebo.(ABSTRACT TRUNCATED AT 250 WORDS)

Immunosuppressive treatment in myocarditis

Twenty patients (13 males and seven females) with a biopsy-proven diagnosis of myocarditis underwent a period of treatment with prednisone and azathioprine. The primary objective of the study was the observation of histologic changes which occur during treatment and after treatment withdrawal. The secondary objective was the detection, if any, of changes in left ventricular ejection fraction. Multiple endomyocardial biopsies were obtained and the treatment was adjusted in order to achieve complete disappearance of the myocardial inflammation. The histologic status was improved in all patients, although complete disappearance of the signs of active disease was seen in 15 patients only. Two patients died during the observation period. A clear relationship between histologic status and immunosuppression was established in some patients (50% of all cases showed a worsening after withdrawal from the treatment). An overall improvement of the ejection fraction was observed (from 0.37 +/- 0.14 to 0.46 +/- 0.17), but a direct effect of the treatment on the recovery of ventricular function cannot be stated. In some patients, however, a direct relationship between the histological changes and the changes in ejection fraction was seen. These data suggest that treatment with prednisone and azathioprine may be beneficial in some patients with biopsy-proven myocarditis and depressed ventricular function.

Beta-adrenergic blocking drugs in the treatment of congestive heart failure

Experimental and clinical data suggests that increased serum catecholamines may have predominantly detrimental effects in patients with congestive heart failure. Some investigators have proposed use of beta-blockers in heart failure as a means of ameliorating the harmful effects of the excess catecholamines. The clinical experience to date with use of these agents as therapy in congestive heart failure is limited but does suggest a future role for beta-blockers as adjunct therapy in a select population of patients with heart failure.

Effect of intravenous metoprolol on left ventricular performance in Q-wave acute myocardial infarction

To determine the effects of intravenous metoprolol on left ventricular (LV) function in acute myocardial infarction (AMI), 16 patients were studied within 48 hours of Q-wave AMI (mean ejection fraction 47 +/- 6%, mean pulmonary artery wedge pressure 22 +/- 6 mm Hg) with high fidelity pressure and biplane cineventriculography before and after intravenous metoprolol (dose 12 +/- 4 mg). Heart rate decreased from 90 +/- 13 to 74 +/- 11 beats/min (p less than 0.001), pulmonary arterial wedge pressure and LV end-diastolic pressure were unchanged (22 +/- 6 to 21 +/- 6 and 27 +/- 8 to 26 +/- 8 mm Hg, respectively), despite impaired LV relaxation (P = Poe-t/T) after intravenous metoprolol (T from 59 +/- 13 to 72 +/- 12 ms, p less than 0.001). Peak systolic circumferential LV wall stress decreased after beta-adrenergic blockade (330 +/- 93 to 268 +/- 89 g/cm2, p less than 0.05) and LV contractility decreased (dP/dtmax from 1,480 +/- 450 to 1,061 +/- 340 mm Hg/s, p less than 0.001). The ejection fraction decreased (48 +/- 7 to 43 +/- 7%, p less than 0.05) due to an increase in LV end-systolic volume (85 +/- 19 to 93 +/- 19 ml, p less than 0.05) since LV end-diastolic volume was unchanged (161 +/- 30 to 163 +/- 30 ml, difference not significant). In patients with Q-wave AMI, intravenous metoprolol reduces the major determinants of myocardial oxygen demand including heart rate, contractility and peak systolic wall stress. Further, despite decreased heart rate, (+)dP/dtmax, ejection fraction, isovolumic relaxation, LV end-diastolic pressure and end-diastolic volume remain unchanged.

Neuro-endocrine changes as new targets in the drug treatment of congestive heart failure

The classical therapy of congestive heart failure (CHF) with inotropic agents (digitalis and newer inotropics) and diuretic agents remains unsatisfactory in many cases. More recently it is recognized, that some of the neuro-endocrine compensatory processes associated with CHF are detrimental in the long run, and therefore potentially targets for drug treatment. This holds for the following neuro-endocrine mechanisms: 1) increased activity of the sympathetic nervous system and high plasma catecholamines, accompanied by down-regulation of beta 1- but not beta 2-receptors in the heart; 2) stimulation of the renin-angiotensin-aldosterone system (RAAS), causing higher levels of renin, A II and aldosterone. The detrimental sequelae of both processes are even enhanced by their complex mutual interactions. Drug treatment aiming to reduce or suppress these processes and their negative results is potentially offered by: vasodilators, counteracting vasoconstriction, low dose selective beta 1-adrenoceptor blockers, which will not only impair tachycardia but also up-regulate cardiac beta 1-receptors and hence improve the inotropic response to catecholamines; aldosterone antagonists and ACE-inhibitors counteracting the activated RAAS. The beneficial effect of the ACE-inhibitors in CHF is well established and superior to that of classical vasodilators, since it additionally counteracts the enhanced RAAS activity.

Beta-blocker therapy in patients with ventricular tachyarrhythmias in the setting of left ventricular dysfunction

Although several studies suggest beta blockers (BB) are effective in suppressing ventricular arrhythmias, less is known about their role in the treatment of patients with ventricular tachyarrhythmias associated with impaired left ventricular function. To assess the tolerance and efficacy of these agents, 32 patients presenting with either ventricular fibrillation (18) or sustained ventricular tachycardia (14) were studied during BB therapy. Left ventricular dysfunction (mean ejection fraction 29%) was present as a consequence of coronary artery disease (26) or cardiomyopathy (6). Baseline arrhythmia assessment revealed recurrent ventricular tachycardia in all patients. Antiarrhythmic drug therapy including BB was guided by programmed stimulation (10), exercise testing (8), ambulatory monitoring (12), or was given empirically (2). Beta blockers were well tolerated, as measured by exercise duration, which improved significantly, and by long-term maintenance, which continued in 23 of 32 (72%) patients. Over a mean follow-up of 668 days, patients treated with BB had a relatively low incidence of both sudden (3%) and nonsudden (9%) death. Thus, BB can be effective and well tolerated adjunct therapy in patients with a history of ventricular tachyarrhythmias in the setting of impaired left ventricular function.

Noninvasive evaluation of the effect of timolol on left ventricular performance after myocardial infarction and the consequence for prognosis

Left ventricular performance was evaluated noninvasively in 111 patients participating at one study center in the Norwegian Multicenter Study on Timolol After Myocardial Infarction. Systolic time intervals were measured in 55 patients treated with timolol and in 56 patients receiving placebo. Measurements were made before randomization, and after 1, 3 and 12 months of treatment. During the treatment period, the pre-ejection period/left ventricular ejection time ratio was significantly lower in the timolol-treated group, indicating better left ventricular function than in the placebo-treated patients. In the 27 patients who died during the follow-up period of 50 to 72 months, there was a significant increase in the pre-ejection period/left ventricular ejection time ratio from baseline to the last performed recording, indicating a deterioration in left ventricular performance in these patients. No such change occurred in the group that survived the entire follow-up period. Deterioration of left ventricular function is related to a high long-term mortality rate after myocardial infarction, and left ventricular function is better preserved in patients treated with timolol than in patients receiving placebo.