[The use of positron emission tomography for noninvasive diagnosis of mitochondrial dysfunction and assessment of myocardial compensatory reserve in children with cardiomyopathies]. / Neinvazivnaia diagnostika mitokhondrial'noi disfunktsii i otsenka kompensatornykh vozmozhnostei miokarda u detei s kardiomiopatiiami s pomoshch'iu pozitronnoi émissionnoi tomografii.

BACKGROUND: Recent experimental and clinical studies have shown that cardiomyopathy (CMP) can be associated with disorders of oxidative metabolism in cardiomyocyte mitochondria. These disorders are connected with deficit of enzymes and complexes of electron transfer chain, and can constitute pathogenetic base of the disease. AIM. To study myocardial metabolism in children with cardiomyopathies using positron emission tomography (PET). METHODS: PET studies were carried out in 17 patients (pts.) aged 3-13 years (mean age 7,5-/+3,1) with CMP: hypertrophic (HCMP, n=4), dilated (DCMP, n=9), after radical correction of tetralogy of Fallot (TF, n=4). The dynamic study with [1-11C]-acetate was performed for evaluation of Krebs cycle activity. Rate constant (kmono) and [11C]-activity elimination half-time (T1/2) were calculated using myocardial time-activity curve. Myocardial perfusion was assessed with [13N]-ammonia, glucose metabolism - with [18F]-fluorodeoxyglucose. RESULTS: Patients with HCMP: left ventricular (LV) perfusion was normal, Krebs cycle activity - decreased; glucose utilization was increased in comparison with normal level in 2, and was normal in 2 other children. Patients with DCMP: LV perfusion was normal; Krebs cycle activity in LV was decreased in 6 and normal - in 3 pts. Overall 2 pts. with CMP had focal perfusion defects. More pronounced decrease of Krebs cycle activity in these regions compared with other LV parts implied development of ischemic injuries. Decrease of glucose utilization in these fields indicated that the injuries were irreversible. Patients with TF: 3 pts. had normal perfusion and Krebs cycle activity; 1 patient with severe hemodynamic disorders had decreased perfusion, glycolysis and Krebs cycle activity in both ventricles indicative of the presence of myocardial dystrophic changes. CONCLUSION: Despite normal perfusion children with cardiomyopathy had decreased Krebs cycle activity (mitochondrial dysfunction). Decrease in oxidative metabolism could be compensated by increased glycolysis.

[Evaluation of the status of cardiac perfusion after implantation of extra-cardiac conduits]. / Otsenka sostoianiia perfuzii serdtsa posle implantatsii extra- kardial'nykh konduitov.

The work discusses the findings of experimental study of perfusion of the myocardium after creation of a peculiar "new" outflow tract from the left ventricle of the heart. As a result, perfusion of a heart with an unnatural outflow tract from the left ventricle was found to be satisfactory. The authenticity of the results was determined by means of two, complementing each other, radioisotope methods--standard study with the use of 201Tl and a new method for producing a positron-emission image. It is concluded that the supply of blood to the myocardium after implantation of an ++apico-aortic conduit is sufficiently effective.

[Assessment of the state of implanted extracardiac conduits by NMR-tomography]. / Otsenka sostoianiia implantirovannykh ékstrakardial'nykh konduitov s pomoshch'iu IaMR-tomografii.

The object of the work was to reveal the unique possibilities of a highly effective noninvasive method NMR-tomography in evaluating the functional condition of extracardiac conduits in experiments. Conduit models with a stationary flow of blood and 10 dogs with implanted left ventricular-aortic conduit were studied. The studies were conducted on a Soviet MT-1000 NMR tomograph. In all studies with diverse cross sections a distinct location of the heart and the large blood vessels and a "new" left ventricular outlet tract was achieved. Minute features of the inner architectonics of the pumping chamber and the lining of the conduit were detected which could not be found by the routine methods. The study allowed certain conclusions to be made concerning the promising application of NMR tomography in the cardiosurgical clinic. With the use of the method some recommendations may be given for optimization of the designs of extracardiac conduits.

[Quantitative analysis of perfusion scintigrams of the myocardium using 201Tl in ischemic heart disease]. / Kolichestvennyi analiz perfuzionnykh stsintigramm miokarda s 201Tl pri ishemicheskoi serdtsa.

Altogether 111 patients with coronary heart disease (CHD) were examined using loading perfusion scintigraphy testing of the myocardium with 201Tl. Quantitative assessment of scintigrams was based on a computer-assisted method proposed by the authors which was used for determination of indices characterizing a degree of perfusion disorder in each segment of the left ventricular myocardium: the M/B ratio (the ratio of a mean level of radioactivity of a myocardial segment to a mean level of background radioactivity) and the TAI (the thallium accumulation index--a quantitative value of segmental perfusion). The method permits the detection of a zone of disturbed perfusion (ischemia, scar changes and left ventricular aneurysm) and quantitative assessment of the depth of scar lesion of the left ventricular myocardium.