THE CANADIAN JOURNAL OF NEUROLOGICAL SCIENCES QUEBEC COOPERATIVE STUDY OF FRIEDREICH'S ATAXIA The Cardiomyopathy in Friedreich's Ataxia: Isotopic Ventriculography and Myocardial Imaging with Thallium-201

Myocardial scanning after the intravenous administration of Thallium 201 was used to evaluate regional myocardial perfusion in 14 patients with Friedreich's ataxia. Isotopic ventriculography was also used to assess left ventricular contractility. Myocardial images in patients with Friedreich's ataxia were found to be precociously abnormal irrespective of the degree of neurological impairment or of the severity of myocardial hypertrophy. RESUME: Chez 14 patients souffrant d'ataxie de Friedreich, nous avons 6valu6 la perfusion myocardique r6gionale apres administration intraveineuse de Thallium 201. Nous avons aussi utilis6 la ventriculographie isotopique pour 6valuer la contractility ventriculaire gauche. Chez les patients avec Friedreich, les images myocardiques s'avSrerent pr6coc6ment anormales, ind^pendamment du degr6 d'atteinte neurologique ou de la s£v6rit6 de l'hypertrophie du myocarde. Can. J. Neurol. Sci. 1984; J 1:588-591 Friedreich's Ataxia is associated with a cardiomyopathy caracterized by mild to moderate left ventricular hypertrophy. The hypertrophy is most often concentric with some cases associated with asymetrical septal hypertrophy and subaortic stenosis (Thoren, 1964 Cote, 1979). The large and small intramural coronary arteries, in our experience, do not present signifiant atherosclerotic involvement (Lamarche, 1980). We used myocardial scanning after the intravenous administration of Thallium 201 to evaluate regional myocardial perfusion and isotopic ventriculography to assess left ventricular contractility and to establish a correlation, if any, between the severity of the cardiomyopathy with age and degree of neurological impairment of these patients. were acquired after the intravenous injection of 1.6 to 2.5 mCi of Thallous chloride 201 by means of a high resolution scintillation camera (Picker Dyna Camera 4) for 3000 counts per cm per projection. Images were obtained in the anterior, 25,45 and 65 degree left anterior oblique and left lateral projections. After back-ground correction, the images were qualitatively analyzed and segmental thallium activity in each projection compared to normals (mean ± 2 SD). Left ventricular ejection fraction was determined from the gated cardiac blood pool scan after the injection of 15 to 20 mCi of " m T c , 20 minutes after a previous injection of stannous chloride.