PERFUSION SCINTIGRAPHY OF THE MYOCARDIUM IN VARIOUS FORMS OF CARDIAC PATHOLOGY IN CHILDREN

Perfusion scintigraphy of the myocardium was carried out with the help of the Millennium MG gamma camera (USA) in synchronization with the ECG in 141 patients aged of from 5 to 15 years. Patients were divided into four groups: 30 chronic myocarditis (CM) patients, 30 hypertrophic cardiomyopathy (HCMP) patients, 30 dilated cardiomyopathy (DCMP) cases and 21noncompact cardiomyopathy (NCMP) patients. The left ventricular (LV) ejection fraction was established to be preserved in CM and HCMC patients (in cases without signs of obstruction), a significant reduction in the ejection fraction was found in NKMP and DCMP patients. The thickness of the myocardium of the LV significantly increased only in HCM patients. The expansion of the LV cavity was detected in all patients, but its decrease was present only in HCM cases. The contractility of the myocardium was impaired in all the patients examined. Disturbances of the myocardial perfusion were the most pronounced in NKMP and DCMP patients. Signs of fibrosis were detected in most patients, but HCM patients. In 40% of CM patients, scintigraphic signs of inflammation were determined. In 17% of all examinations there was noted hyperperfusion of the right ventricular myocardium. The authors believe myocardial tomoscintigraphy to be the unique method for analyzing myocardial viability in various forms of cardiac pathology that can be used for the evaluation of the effectiveness of the treatment.

Maternal Cardiac Function after Normal Delivery, Preeclampsia, and Eclampsia: A Prospective Study

Introduction. The aim of this study is to assess maternal cardiac function in the postpartum period, after 2 and 6 months in the parturient with preeclampsia and eclampsia. Materials and Methods. Prospective study: 90 postpartum women after preeclampsia and eclampsia and 55 patients after an uncomplicated pregnancy. The parameters of maternal hemodynamics were recorded on days 1, 3, 5, 9, and 14 of postpartum period, after 2 and 6 months. The cardiac parameters were assessed. Results. PE is accompanied by increased peripheral vascular resistance. The indicator of vascular resistance, SVR, is elevated for both mild and severe PE. With mild PE, a significant increase in SVR is observed up to 5 days of postpartum period, with severe PE/E up to 9 days. We found that in case of severe PE, SVR remains elevated to 6 months after delivery. The parameters of the contractile function of the heart (ESV, EDV, SV, SI, CO, СI, MVCF) were significantly decreased: with mild PE up to 5-9 days, with severe up to 9-14 days of puerperia. ESV, SV, SI, CO, and CI remain low with severe PE up to 6 months. The revealed decreasing of contractile function of the heart is a sign of asymptomatic heart failure. Conclusions. The hemodynamics of the puerperas after PE and E is characterized by impaired contractility of the myocardium and an increase in the indices of peripheral resistance. The degree of deviation in the parameters of cardiac hemodynamics and vascular resistance depended on the severity of hypertensive complications of pregnancy.

Diagnostic capabilities of electrocardiography systolic heart failure

The contractility of the myocardium is determined by the strength and speed of contraction of the ventricles. It can be estimated from the Q-T interval of the electrocardiogram, which is an electrical systole of the ventricles. Set the change in ventricular systole by the deviation of the actual interval of Q-T from the corrected one. Elongation of ventricular systole indicates a violation of myocardial contractility, which causes the development of systolic heart failure. When comparing this indicator with the results of echocardiography, reflecting the contractility of the left ventricle, their direct dependence was established. The greater the degree of breach of myocardial contractility, the higher the percentage of the deviation of the actual Q-T interval from the corrected one. The maximum figures were recorded in patients with a global contractility disorder. This indicator can be used to detect both acute and chronic systolic insufficiency. It was established that in all patients with heart failure there was an increase in the Q-T interval. The magnitude of it depended on the degree of manifestation of heart failure. The increase in the percentage deviation of the actual value from the control occurred in patients with heart failure from I functional class to IV. Only in 1/5 of patients with heart failure of I functional class, the actual value did not differ from the control one, but under physical load, it increased significantly, which indicates the presence of latent systolic insufficiency. It is also found in patients with heart failure with a preserved ejection fraction, the development of which is associated with diastolic dysfunction. Electrocardiography can be used as a method of diagnosing systolic heart failure, which is highly informative and specific.

Updating Experimental Models of Diabetic Cardiomyopathy

Diabetic cardiomyopathy entails a serious cardiac dysfunction induced by alterations in structure and contractility of the myocardium. This pathology is initiated by changes in energy substrates and occurs in the absence of atherothrombosis, hypertension, or other cardiomyopathies. Inflammation, hypertrophy, fibrosis, steatosis, and apoptosis in the myocardium have been studied in numerous diabetic experimental models in animals, mostly rodents. Type I and type II diabetes were induced by genetic manipulation, pancreatic toxins, and fat and sweet diets, and animals recapitulate the main features of human diabetes and related cardiomyopathy. In this review we update and discuss the main experimental models of diabetic cardiomyopathy, analysing the associated metabolic, structural, and functional abnormalities, and including current tools for detection of these responses. Also, novel experimental models based on genetic modifications of specific related genes have been discussed. The study of specific pathways or factors responsible for cardiac failures may be useful to design new pharmacological strategies for diabetic patients.

Effect of twitch interval duration on the contractile function of subsequent twitches in isolated rat, rabbit, and dog myocardium under physiological conditions

Many studies have shown that a change in stimulation frequency leads to altered contractility of the myocardium. However, it remains unclear what changes occur directly after a change in frequency and which ones are a result of the slow processes that lead to the altered homeostasis, which develops after a change in stimulation frequency. To distinguish the immediate from the slow responses, we assessed contractile function in two species that have distinctively different calcium (Ca2+)-handling properties using a recently developed, randomized pacing protocol. In isolated dog and rat right ventricular trabeculae, twitch contractions at five different cycle lengths within the physiologic range of each species were randomized around a steady-state frequency. We found, in both species, that the duration of the cycle length just prior to the analyzed twitch (primary) positively correlated with the increased force of the analyzed twitch. In sharp contrast, the cycle lengths, one and two more removed from the analyzed twitch (“secondary” and “tertiary”), displayed a negative correlation with force of the analyzed twitch. In additional experiments, assessment of intracellular Ca2+ transients in rabbit trabeculae revealed that diastolic Ca2+ levels were closely correlated to contractile function outcome. The relative contribution of the primary cycle length was different between dog (51%) and rat (71%), whereas in neither species was a significant effect on relaxation time observed. With the use of randomized cycle lengths, we have distinguished the intrinsic response from the signaling-mediated effects of frequency-dependent activation on myofilament properties and Ca2+ handling.

Features of aerobic glucose oxidation and the functional state of the myocardium in pneumonia in young children

The state of aerobic oxidation of glucose was studied in 146 children with acute pneumonia and in 50 healthy children by determining the activity of lactate dehydrogenase, malate dehydrogenase and their isoenzymes, the content of pyruvic acid in the blood. It has been clinically established that with pneumonia there are violations of the contractility of the myocardium. Moreover, these disorders are in direct proportion to the depth of the shift in the ratio of aerobic and anaerobic processes in the body.

Cardiac Arrhythmia in a Child Due to Chloral Hydrate Ingestion

The recommended hypnotic dose of chloral hydrate depresses the cerebral hemisphere and induces sleep without significant change in respiration, blood pressure, or heart rate. With higher doses the respiratory rate may be depressed and the blood pressure reduced due to inedullary depression and peripheral cutaneous vasodilation.1,2 Chloral hydrate "in large doses depresses the contractility of the myocardium and shortens the refractory period."1 Toxic doses produce untoward cardiac effects especially in patients with heart disease.1 Reports of significant cardiac arrhythmia caused by chloral hydrate are rare.3-5. We present what we believe to be the first report of serious cardiac arrhythmia caused by chloral hydrate in a child.