Beta-blocker Therapy For Dilated Cardiomyopathy Research Articles

Changes in Left Atrial Chamber Size Predicts Response to Beta-blocker Therapy in Patients with Dilated Cardiomyopathy

To clarify the relationship between left atrial (LA) and ventricular (LV) systolic function responded to beta-blocker (BB) in dilated cardiomyopathy (DCM), we investigated echocardiographic parameters before and 1, 3, 6, 12 months (M) after the initiation of carvedilol in 21 patients. NYHA class was improved in 15 patients (71%) during follow-up. LV ejection fraction (EF) was gradually increased (26.3±8.7 at baseline vs. 51.9±8.8% at 12 M, p<0.001) with significant decreased LV diastolic and LA dimensions (LAD: 51.2±7.9 at baseline vs. 45.2±9.2mm at 12M, p<0.01). Restrictive pattern of mitral flow, mitral regurgitation and enlarged LAD were improved in early stage. Figure showed a negative correlation between % of delta EF and delta LAD at 12 M. Decrease of LAD can predict the improvement of LV systolic function by BB therapy in DCM.

An Appropriate Indication for the Initiation of Beta-Blocker Therapy in Dilated Cardiomyopathy

Backgrounds: Although long-term treatment with beta-blockers has been shown to improve morbidity and mortality in dilated cardiomyopathy (DCM), patient re- sponses are heterogeneous. Methods: To establish the appropriate indication for the initiation of beta-blocker therapy, we retrospectively analyzed 38 DCM patients treated with beta-blockers (metoprolol or carvedilol) and examined differences in baseline profiles between patients who could continue the therapy (responders) and those who could not (non-responders). Results: In 13 non-responders, the duration from onset of symptoms to beta-blocker initiation was longer (p < 0.05), systolic blood pressure was lower (p < 0.001), serum sodium concentration was lower (p < 0.05), left ventricular posterior wall thickness was thinner (p < 0.05), left ventricular end-diastolic pressure was higher (p < 0.05) and left ventricular wall stress was lower (p < 0.05) than in 25 responders. In 19 patients receiving carvedilol, 5 non-responders showed higher levels of human atrial natriuretic peptide (p < 0.05) and brain natriuretic peptide (p < 0.01) than 13 responders. Discriminant analysis with a linear discriminant function showed the following equation predicted response to beta-blocker therapy: h = 0.004 × systolic blood pressure – 0.002 × brain natriuretic peptide + 0.667 (R² = 0.67, p < 0.001). The probability of predicting the response was 94.1% with h ≧0.5. Conclusion: We conclude that h≧0.5 is the appropriate indication for the initiation of beta-blocker therapy in DCM.

The factor which predicts continuation and prognosis of beta-blocker therapy for dilated cardiomyopathy

Purpose: We study a clinical characteristic of the beta-blocker therapy for the patients with DCM. Subject: We intended for 39 patients with DCM who took administration of beta-blocker. Methods: We devided into the beta-blocker therapy continuation group and the non-continuation group more than three years, into the group that caused cardiac events and the group that did not cause, and into the BNP less than 200 pg/ml group and the more than 200 pg/ml group.We performed statistical examination in each group. Results: A group of non-continuation had low serum Na value, and age was high. BNP value was high a lot of self-withdrawal history of ingestion in a group of cardiac events caused. The group that BNP values were more than 200pg/ml had low three years survival rate, and serum Na value and left ventricular ejection fraction decreased. Conclusions: Blood BNP value, serum Na value are very useful in continuation of beta-blocker therapy for the patients with DCM.

Effect of beta-blocker treatment in dilated cardiomyopathy with bradyarrhythmias.

This study was performed to evaluate whether beta-blocker therapy was effective in patients with nonischemic dilated cardiomyopathy (DCM) and bradyarrhythmias supported by pacemaker implantation. Beta-blocker therapy is useful for some patients with DCM, especially those with rapid heart rate or residual nonfibrotic myocardium in the left ventricle, but no data exist on whether beta-blocker therapy is useful in patients with DCM and bradyarrhythmias. The effectiveness of beta-blocker therapy was prospectively evaluated in patients with DCM and bradyarrhythmias supported by pacemaker implantation and compared with those without these arrhythmias. Beta-blocker therapy was started in 63 patients (45 men, 18 women, aged 11-83 years) with DCM, in whom 7 had bradyarrhythmias and 56 did not. These bradyarrhythmias were atrioventricular block, sick sinus syndrome and atrial fibrillation with slow heart rate. Of the 56 patients without bradyarrhythmias, 42 (75%) (group 1) responded to beta-blocker therapy, but 5 of the 7 with bradyarrhythmias (71%) (group 2) also responded. Left ventricular end-diastolic dimension was reduced (6.5 +/- 0.6 cm to 5.6 +/- 0.5 cm; p < 0.0001 in group 1; 6.6 +/- 0.8 cm to 5.5 +/- 0.2 cm; p < 0.02 in group 2) and left ventricular fractional shortening was improved (13 +/- 4% to 27 +/- 7%; p < 0.0001 in group 1; 12 +/- 4% to 29 +/- 10%; p < 0.05, in group 2) to the same degree in both groups. These results indicate that beta-blocker therapy for DCM is effective not only in patients without bradyarrhythmias but also in those with bradyarrhythmias supported with pacemaker implantation.

Exercise-induced upward shift of diastolic left ventricular pressure-volume relation in patients with dilated cardiomyopathy. Effects of beta-adrenoceptor blockade.

The effectiveness of beta-blocker therapy for dilated cardiomyopathy (DCM) may be attributed to the inhibition of detrimental effects on the failing heart of sympathetic stimulation during exertion. However, the harmful effects of activity as well as the protective effects of beta-blockers have not been demonstrated. Diastolic ventricular function is known to be sensitive to transient myocardial metabolic insult. In this study, we investigated the effect of modest exercise with or without beta-blockade on the diastolic left ventricular pressure-volume (P-V) relation in patients with DCM. The diastolic left ventricular P-V relation was obtained by high-fidelity pressure measurements and digital subtraction left ventriculography at rest and immediately after modest supine bicycle exercise in 12 patients with DCM. The effects of intravenous administration of 0.1 mg/kg propranolol on resting and exercise P-V relations were studied. The end-diastolic and lowest left ventricular pressures were significantly elevated by exercise (20 +/- 9 to 32 +/- 13 mm Hg, P < .01, and 12 +/- 6 to 21 +/- 11 mm Hg, P < .01, respectively) despite insignificant changes in left ventricular volumes. The administration of propranolol did not alter the resting diastolic P-V relation. However, propranolol significantly attenuated the exercise-induced upward shift of the diastolic P-V relation despite a significant increase in end-diastolic volume. The significant upward shift and attenuation by propranolol were also observed even when the left ventricular pressure was corrected by the subtraction of right atrial pressure. These results indicate that even modest exercise exerts detrimental effects on diastolic left ventricular function of the failing heart through beta-adrenergic stimulation. The clinical effectiveness of beta-blocker therapy in patients with DCM can be attributed in part to the inhibition of detrimental myocardial effects of sympathetic stimulation during daily activity.

Which subgroup of patients with dilated cardiomyopathy would benefit from long-term beta-blocker therapy? A histologic viewpoint

Objectives. The purpose of this study was to elucidate whether the effectiveness of long-term beta-blocker therapy could be predicted before this therapy is started.Background. Long-term beta-blocker therapy has recently been reported to provide a favorable effect in treatment of congestive heart failure due to dilated cardiomyopathy.Methods. Several measurements including histologie variables before administration of metoprolo'. were retrospectively compared among 18 good responders (showing improvement of at least one New York Heart Association functional class or an increase in ejection fraction ≥0.10 12 months after drug administration) and 12 poor responders without such improvement.Results. Although there were no significant differences between the two groups in age, gender, functional class, heart rate, blood pressure, pulmonary capillary wedge pressure, cardiac index, left ventricular end-diastolic dimension and ejection fraction, percent fibrosis estimated by the point-counting method in endomyocardial biopsy specimens was significantly lower in good than in poor responders (7.6 ± 5.7 vs. 14.2 ± 9.7%, p < 0.05). Moreover, when the types of fibrosis were classified as interfascicular and intercellular by the dominance of counted points, there were 13 cases of interfascicular fibrosis and 5 cases of intercellular fibrosis in good responders and 1 case of interfascicular fibrosis and 11 cases of intercellular fibrosis in poor responders (p < 0.001, sensitivity 72%, specificity 91%, predictive accuracy 80%). These results suggest that improvement with long-term beta-blocker therapy may be more likely to occur in patients with less myocardial fibrosis, with interfascicular fibrosis the dominant type.Conclusions. The extent and type of fibrosis may be important factors in the prediction of the effectiveness of long-term betablocker therapy for dilated cardiomyopathy.

Effectiveness of long-term beta-blocker therapy for dilated cardiomyopathy—echocardiographical follow-up

To evaluate the effectiveness of long-term beta-blocker therapy for dilated cardiomyopathy (DCM), two groups (Group I: 18 patients, Group II: 17 patients) with DCM divided by the order at the entry were followed echocardiographically for 16.9 +/- 3.0 months in Group I and 21.4 +/- 3.9 months in Group II. Metoprolol (final dose: 60 mg/day) was administered in Group I, but not in Group II (the control), although the conventional treatment for heart failure was continued. The left ventricular end-systolic dimension and ejection fraction assessed by echocardiography improved significantly after 6 months in Group I, but not in Group II, even after 48 months, although there were no significant differences in baseline data between the two groups. The end-diastolic dimension decreased significantly after 12 months in Group I only. It was estimated, using the point count method on a left ventricular endomyocardial biopsy specimen taken at entry, that the improvement (delta EF) of the ejection fraction 12 months after metoprolol administration inversely correlated (r = -0.677, p less than 0.01) with percent fibrosis, indicating that the more myocardium remains, the more improvement is expected. These findings suggested a favorable effect of beta blockade in DCM, especially in cases with less fibrosis, showing that the endomyocardial biopsy could be of clinical use in selecting candidates for chronic beta-blocker therapy in DCM.