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Effect of beta-blocker treatment in dilated cardiomyopathy with bradyarrhythmias
1Department of Internal Medicine, Osaka Medical College, Japan. in3028@poh.osaka-med.ac.jp
Insights
Beta-blocker therapy is effective for patients with dilated cardiomyopathy (DCM), even those with bradyarrhythmias requiring pacemakers. This treatment improves heart function similarly in both patient groups.
Area of Science:
- Cardiology
- Pharmacology
Background:
- Beta-blocker therapy is established for some patients with dilated cardiomyopathy (DCM).
- Limited data exist on beta-blocker efficacy in DCM patients with bradyarrhythmias.
- Bradyarrhythmias often necessitate pacemaker support in DCM patients.
Purpose of the Study:
- To evaluate the effectiveness of beta-blocker therapy in patients with DCM and bradyarrhythmias supported by pacemakers.
- To compare outcomes in DCM patients with and without bradyarrhythmias receiving beta-blocker therapy.
Main Methods:
- Prospective evaluation of beta-blocker therapy in 63 DCM patients.
- Comparison between 7 patients with bradyarrhythmias (group 2) and 56 without (group 1).
- Assessment of left ventricular dimensions and fractional shortening.
Main Results:
- Beta-blocker therapy showed comparable effectiveness in both groups.
- Significant reduction in left ventricular end-diastolic dimension in both group 1 (p < 0.0001) and group 2 (p < 0.02).
- Significant improvement in left ventricular fractional shortening in both group 1 (p < 0.0001) and group 2 (p < 0.05).
Conclusions:
- Beta-blocker therapy is effective for DCM patients with bradyarrhythmias requiring pacemaker implantation.
- Treatment benefits, including improved cardiac function, are similar to those without bradyarrhythmias.
- Beta-blockers represent a viable therapeutic option for a broader range of DCM patients.
Abstract:
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.