Cardiac manifestations in disorders of fat and carnitine metabolism in infancy

Department of Pediatrics, Hospital for Sick Children, Toronto, Ontario, Canada.

The prognosis of patients with cardiomyopathy associated with hypocarnitinemia is uncertain. Cardiac hemodynamics, histologic findings and response to oral L-carnitine therapy were retrospectively evaluated in 11 children with cardiomyopathy associated with abnormal carnitine metabolism. Three had systemic carnitine deficiency, two familial hypocarnitinemia with neutropenia, three transient neonatal hypocarnitinemia and three a carnitine insufficiency syndrome. Six had a hypertrophic and five a dilated cardiomyopathy. Hypotonia was present in seven (64%). The cardiothoracic ratio was greater than 0.60 in eight (73%). The most frequent abnormality on the electrocardiogram was ST-T wave inversion in the left precordial leads with various degrees of left ventricular hypertrophy. Echocardiographically, two patients with hypertrophic cardiomyopathy had decreased left ventricular function and two patients with dilated cardiomyopathy had increased thickness of the left ventricular wall. Histologic evaluation (two autopsies and one endomyocardial biopsy) revealed striking lipid accumulation within hypertrophied myocytes. Six of eight patients on carnitine replacement therapy had improvement echocardiographically during a 3 month to 2 year follow-up period. In summary, both hypertrophic and dilated cardiomyopathy can result from abnormal carnitine metabolism. The determination of plasma carnitine concentrations and fatty acid metabolism by-products should be performed in all patients with either form of cardiomyopathy of unknown etiology because carnitine supplementation may lead to improvement.

This article has been cited by other articles:

				K. Mizushige, T. Tokudome, M. Seki, I. Kondo, K. Hirao, S. Nozaki, S. Miki, S. Yuasa, H. Matsuo, and K. Mizushige Sensitive Detection of Myocardial Contraction Abnormality in Chronic Hemodialysis Patients by Ultrasonic Tissue Characterization with Integrated Backscatter Angiology, March 1, 2000; 51(3): 223 - 230. [Abstract] [PDF]

				M. D. Cheitlin, J. S. Alpert, W. F. Armstrong, G. P. Aurigemma, G. A. Beller, F. Z. Bierman, T. W. Davidson, J. L. Davis, P. S. Douglas, L. D. Gillam, et al. ACC/AHA Guidelines for the Clinical Application of Echocardiography : A Report of the American College of Cardiology/ American Heart Association Task Force on Practice Guidelines (Committee on Clinical Application of Echocardiography) Developed in Collaboration With the American Society of Echocardiography Circulation, March 18, 1997; 95(6): 1686 - 1744. [Full Text]

				M. L. Schwartz, G. F. Cox, A. E. Lin, M. S. Korson, A. Perez-Atayde, R. V. Lacro, and S. E. Lipshultz Clinical Approach to Genetic Cardiomyopathy in Children Circulation, October 15, 1996; 94(8): 2021 - 2038. [Abstract] [Full Text]

				S. Winter, K. Jue, J. Prochazka, P. Francis, W. Hamilton, L. Linn, and E. Helton The Role of L-Carnitine in Pediatric Cardiomyopathy J Child Neurol, November 1, 1995; 10(2_suppl): 2S45 - 2S51. [Abstract] [PDF]

				S. L. Bratton, A. L. Garden, T. P. Bohan, J. W. French, and W. R. Clarke A Child With Valproic Acid-Associated Carnitine Deficiency and Carnitine-Responsive Cardiac Dysfunction J Child Neurol, October 1, 1992; 7(4): 413 - 416. [Abstract] [PDF]