[Some mechanisms and causes of silent myocardial ischemia].

Some causes of silent heart attack in patients with ST-segment depression are presented in the article. Silent myocardial ischemia was shown to have some common features associated with heart attack with pain syndrome (HAPS). They are the duration of a heart attack, heart rate and the extent of ST-segment depression. It means that the previously proposed theory of "threshold ischemia" does not always reflect real causes of the pain absence during myocardial ischemia events. Nowadays the pain threshold in patients with silent myocardial ischemia has been noted by investigators to exceed that in patients with HAPS by more than 50-100%. Certain differences in mechanisms of pain reception at the level of receptor, its modulation and consequent reception by different parts of the central nervous system were established. It was also shown that the sympathetic-adrenal system and opioid hormones influence significantly on pain sensitivity by the human body. Thus, there are many causes of silent myocardual ischemia and it is still not fully accepted by all researchers.

[Comparative characteristics of the diagnostic methods in silent myocardial ischemia].

This part of the work contains the results of the comparative analysis of the graded physical loading (GFL) and Holter electrocardiogram monitoring (HEM) data. A silent false-negative depression of ST-segment during HEM was observed only in 2.5-8% of all investigated patients. It was established that the use of tests with GFL, HEM and hyperventilation allowed diagnosing more patients with silent myocardial ischemia as well as ST-segment dislocations have been seen in 97.2% cases. 9.1% of clinically healthy patients with risk factors and ST-segment depression were shown by means of myocardial scintigraphy with 201-T1 contrast. 50% of examined patients had silent ST-segment depression after psycho-emotional stress-tests. The comparison of the results of HEM and stress-tests showed that a ST-segment shift was more distinct in patients with episodes of symptomatic and silent myocardial ischemia than in those with silent myocardial ischemia. The article presents findings concerning the rate of ST-segment changes after the GEL test in recovery period. 5 types of ST-segment shift were distinguished.

[Alterations in coronary arteries and frequency of episodes of transient myocardial ischemia in patients with ischemic heart disease with typical and atypical angina pectoris]. / Porazhenie venechnykh arterii i chastota opredeleniia épizodov tranzitornoi ishemii miokarda u bol'nykh ishemicheskoi bolezn'iu serdtsa s tipichnoi i netipichnoi stenokardiei.

A total of 169 patients with ischemic heart disease were examined. Group I comprised 105 patients with angina pectoris, group II was 64 patients presenting with an untypical pain syndrome. A single affection of the coronary artery (CA) was more frequently seen in group II subjects (50 percent versus 16.1% in group I persons). Affection of three CA was more common in group I subjects (41.1% versus 30%). Affection of the main stem of the left coronary artery was recordable in 7.6 percent of subjects in group I and was undetectable in group II patients. It has been established that both in single and associated affections of CA, affection of the right CA and that of the circumflex branch was significantly more common in group II subjects. With affection of two and three CA in persons with stenocardia, there was no significant difference between the number of algesic and non-algesic episodes of myocardial ischemia (MIE) (44.4 and 55.6% and 41.6 and 58.3% respectively). In those examinees without typical stenocardia, in affection of two CA the algesic MIE comprised 20%, non-algesic--80%; in affection of three CA algesic MIE came up to 55.6%, non-algesic--44.4%. In this way, in affection of three CA, the number of both algesic and non-algesic MIE in angina persons was not significantly different from that in subjects free from angina.

[Pain sensitivity threshold in patients with ischemic heart diseases with and without stable angina with episodes of "silent" myocardial ischemia]. / Porog bolevoi chuvstvitel'nosti u bol'nykh ishemicheskoi bolezn'iu serdtsa so stabil'noi stenokardiei i bez takovoi s épizodami "nemoi" ishemii miokarda.

A total of 124 coronary patients were examined. Group I comprised 52 patients with stabile angina, group II was 72 patients free from angina. In all patients, 24-hour ECG monitoring was carried out together with veloergometry (VEM), coronaryangiography. Determined in the above patients was also threshold of pain sensitivity (PST) by using the precardiac area electroskin stimulation technique. The frequency of pain-free episodes of myocardial ischemia (PFMI) in subjects with stabile angina has not been found to be different from that in those free from it. There was no difference in depth and duration of depression of ST segment either. No significant differences were found out between PFMI and pain episodes of myocardial ischemia in group I subjects. PST in both groups subjects was not associated with the number of damaged coronary arteries (CA) and presence of the asynergic zones in the left ventricle (LV). In angina-free subjects presenting with the single CA affection, the right coronary artery (RCA) appeared to be affected much more frequently than in those patients with stabile angina. No primary damage to RCA could be seen in associated CA afflictions.

[Effort tolerance in patients with angina and in those free from typical angina in isolated and multiple disturbances of the coronary arteries]. / Perenosimost' fizicheskoi nagruzki bol'nymi ishemicheskoi bolezn'iu serdtsa co stabil'noi stenokardiei i bez takovoi pri izolirovannom i mnozhestvennom porazhenii venechnykh arterii.

Examined in the study were 169 patients with ischemic heart disease divided into two groups: group I comprised 105 patients with angina, group II was 64 patients who did not have typical stenocardia. All patients were subjected to exercise test and coronoangiography (CAG). Angina patients with transitory ischemia in a VEM-test have not been found to differ from patients without typical angina with transitory ischemia of the myocardium provoked by exercise. Transitory ischemia of the myocardium occurring in those persons free from typical angina has the same prognostic value as in patients with angina.

[The functional characteristics of patients with the silent form of ischemic heart disease]. / Nekotorye osobennosti sostoianiia bol'nykh s bezbolevoi formoi ishemicheskoi bolezni serdtsa.

A total of 124 patients with ischemic heart disease (IHD) were studied. Of these, 53 presented with painless IHD form, 28 patients had atypical pain syndrome. It has been shown that the threshold exercise level both in those persons free from angina pectoris but with postinfarction cardiosclerosis and those with no history of myocardial infarction is not significantly different from and is appreciably higher than in IHD patients with angina pectoris and episodes of "silent ischemia". Informative value has been studied of other diagnostic tests in the above patients: stress-test appeared to be positive in 42.8% of patients, cold test--in 6.3%, hyperventilation test in 16.8% of patients. Painless myocardial infarction (PMI) was detected in 50% of patients with postinfarction cardiosclerosis and 63.6% with no history of myocardial infarction, as evidenced by 24-h ECG monitoring. Analysis of angiogrammes in those persons with atypical pain syndrome showed hemodynamically significant injury to the coronary vessels in 57.1% of patients and a spasm of coronary vessels in 33.3%. PMI occurs in patients with different IHD forms including those with prior MI free from stenocardia.

[Errors in postmortem diagnosis in cardiovascular diseases]. / Oshibki v posmertnoi diagnostike pri serdechno-sosudistykh zabolevaniiakh.

An analysis of out-patients case histories and death certificates indicates that in 22.5-35% of cases the diagnoses in death certificates did not correspond with data of examinations carried out during life when pathological examination was not made; when pathological examination or forensic studies were carried these errors reduced to 10-20%. In another 11.5% the diagnosis of ischemic heart disease was not substantiated because additional examination with the purpose to verify the diagnosis were not carried out.

[An electrocardiographic electrode for the extremities]. / Elektrokardiograficheskii élektrod dlia konechnostei.

A design of electrocardiographic electrode for extremities is described. It contains a double-sided grip (from the insulating material) in the form of a truncated ellipse with the ends smoothly diverged. The results of tests are adduced.

[Effectiveness of physical training in patients who have had a myocardial infarct]. / Effektivnost' fizicheskikh trenirovok u bol'nykh, perenesshikh infarkt miokarda.

A study of the effects of exercise on cardiovascular function of myocardial infarction survivors showed their physical stress tolerance to increase as a result of improved myocardial contractility and the optimum adjustment of hemodynamic and oxygen support of exercise. Therefore, exercise should be used more extensively as part of the rehabilitation effort following myocardial infarction.

[The role of electrocardiotopography in evaluation of a graded exercise test during rehabilitation of patients who had myocardial infarction]. / Znachenie élektrokardiotopografii dlia otsenki proby s dozirovannoi fizicheskoi nagruzkoi pri reabilitatsii bol'nykh, perenesshikh infarkt miokarda.

A total of 217 male survivors of myocardial infarction with resumed working capacity were monitored. Their electrocardiotopography, with ECG recordings from 36 leads on anterolateral surface of the chest, was examined in order to assess tolerance to rationed exercise by bicycle ergometry. The multiple lead recording techniques is shown to give more objective results, as compared to the conventional routine procedure, in analyzing causes of test discontinuation and evaluating changes in exercise tolerance during prolonged monitoring. Chest electrode placed in the 4th and 5th positions was not shown to possess any preferential informative value with respect to effects of exercise tests.

[Electrode for the pickup of bioelectrical potentials]. / Elektrod dlia s''ema bioélektricheskikh potentsialov.

Three versions of surface multipoint electrodes are described providing electrical contact with the body surface without any electrode paste. The electrical contact is achieved through numerous metal pins being electrically connected with each other. One electrode has all its pins fixed rigidly on a common base-plate. In two other versions the pins are movable by means of special springs and volumetric elastic (springy) materials which allows to ensure electrical contact with uneven body surface.