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

Division of Cardiology, Osaka Prefectural Hospital, Japan.

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 histologic variables before administration of metoprolol 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 > or = 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 beta-blocker therapy for dilated cardiomyopathy.

This article has been cited by other articles:

				K. Fukuchi, Y. Yasumura, K. Kiso, K. Hayashida, K. Miyatake, and Y. Ishida Gated Myocardial SPECT to Predict Response to {beta}-Blocker Therapy in Patients with Idiopathic Dilated Cardiomyopathy J. Nucl. Med., April 1, 2004; 45(4): 527 - 531. [Abstract] [Full Text] [PDF]

				S. Hasegawa, H. Kusuoka, K. Maruyama, T. Nishimura, M. Hori, and J. Hatazawa Myocardial positron emission computed tomographic images obtained with fluorine-18 fluoro-2-deoxyglucose predict the response of idiopathic dilated cardiomyopathy patients to beta-blockers J. Am. Coll. Cardiol., January 21, 2004; 43(2): 224 - 233. [Abstract] [Full Text] [PDF]

				E. J. Eichhorn, P. A. Grayburn, S. A. Mayer, M. St John Sutton, C. Appleton, J. Plehn, J. Oh, B. Greenberg, A. DeMaria, R. Frantz, et al. Myocardial Contractile Reserve by Dobutamine Stress Echocardiography Predicts Improvement in Ejection Fraction With {beta}-Blockade in Patients With Heart Failure: The {beta}-Blocker Evaluation of Survival Trial (BEST) Circulation, November 11, 2003; 108(19): 2336 - 2341. [Abstract] [Full Text] [PDF]

				T. Toyama, H. Hoshizaki, R. Seki, N. Isobe, H. Adachi, S. Naito, S. Oshima, and K. Taniguchi Efficacy of Carvedilol Treatment on Cardiac Function and Cardiac Sympathetic Nerve Activity in Patients with Dilated Cardiomyopathy: Comparison with Metoprolol Therapy J. Nucl. Med., October 1, 2003; 44(10): 1604 - 1611. [Abstract] [Full Text] [PDF]

				H Kitaoka, J Takata, T Yabe, N Hitomi, T Furuno, and Y L Doi Low dose dobutamine stress echocardiography predicts the improvement of left ventricular systolic function in dilated cardiomyopathy Heart, May 1, 1999; 81(5): 523 - 527. [Abstract] [Full Text]

				T Yamada, M Fukunami, T Shimonagata, K Kumagai, J Kim, S Sanada, H Ogita, M Hori, and N Hoki Prediction of the effectiveness of long term beta  blocker treatment for dilated cardiomyopathy by signal averaged electrocardiography Heart, March 1, 1998; 79(3): 256 - 261. [Abstract] [Full Text]