Prevalence of ischaemic heart disease and of various electrocardiographic changes according to findings of the cooperative Moscow-Kaunas-Minsk study.

In the cooperative study of multifactorial prevention of ischaemic heart disease (IHD), conducted in Moscow, Kaunas and Minsk, the authors investigated and compared the prevalence of IHD, its various forms, ECG changes and the awareness of the IHD patients that they were affected by this disease. Preventive examination of the male population in the 40 to 59 years age group revealed the presence of IHD in 14.8% in Moscow, 10.7% in Kaunas and 14.1% in Minsk. In the male population in Moscow IHD has a more severe course with the prevalence of painful forms, whereas in Kaunas there occur in more than 50% of the patients and in Minsk in 49% painless forms of IHD. Myocardial infarction occurs in Moscow more frequently (3.7%) than in Minsk (3.1%) and in Kaunas (2.5%), and is in Moscow in a higher percentage of cases associated with signs of pronounced cicatricial changes in the myocardium on the ECG. Angina pectoris of effort occurred among persons without MI in Kaunas in 2.4%, in Minsk twice as frequently (4.8%) and in Moscow nearly three times as frequently (6.8%). Of the persons in whom examination established the presence of IHD or angina pectoris of effort, every third in Moscow and every second in Kaunas and Minsk was not aware of their disease.

A lowering of the risk of ischaemic heart disease among the population (according to the results of the Kaunas preventive study).

Out of the total number of 2455 individuals who had passed a primary screening, a group of men aged 45--59 years, with average (borderline) values of arterial pressure (AP), serum cholesterol (CH), and glucose levels after the glucose load, was selected for studies of potential lowering of the level of risk factors of ischaemic heart prevention. The enrollment of the probands lasted 9.4 months on the average (+/- 6.0 months); the preventive double-blind study proper lasted 12 months. The levels of the three specified risk factors sank both during the enrollment period and during the proper 1-year preventive therapy period. The risk factor levels were substantially lowered both in consequence of repetitive regular examinations and by the action of drug treatment (this applies especially to the CH level). In the evaluation of the results of the preventive study, therefore, also the effects of the lowering of the AP and of the CH and glucose levels even to the average values have to be taken into account. The results of the preventive study confirm that it is possible to lower the risk of IHD among the population.

Standardized Minnesota coding of electrocardiographic findings for purposes of cooperative research on ischaemic heart disease.

For purposes of cooperative research on multifactorial prevention of ischaemic heart disease, a standardization system was elaborated in the USSR for classification of ECG findings according to the Minnesota code. The system includes instruction about the coding rules, experimental coding, analysis of faulty codings, and finally a control test consisting in encoding several series of 200 ECG findings each. For assessing the encoder's qualification the criterion was accepted of less than 20% cases of discordance with the standard code of "ischaemic" ECG changes. It was found that after the initial instructive course it was necessary to gain experience with encoding at least 1 000 ECG to qualify the candidate for the specified expert level. The necessity is emphasized of continual surveillance of the quality of ECG classification by the encoders in different centres, and the possibility of reaching a satisfactory level of unification is declared.

Relationship between smoking and ischaemic heart disease mortality in male population of Kaunas, aged 45-59 years.

Out of 2392 men aged 45--59 years, examined in accordance with the WHO standard methods for detection of risk factors of ischaemic heart disease (IHD), within the follow-up period from March, 1972, till February, 1978, 96 persons died. Considerable differences were found in the proportion of ex-smokers and non-smokers in the group of individuals without IHD and among patients with IHD. Among all deceased subjects in those deceased of IHD and among the persons without IHD the proportion of smokers was considerably higher than the proportion of non-smokers. In the smokers the most frequent cause of death were malignant tumours. Overall mortality and mortality due to IHD were markedly higher in smokers as compared to ex-smokers. Considerably lower values of systolic, diastolic arterial pressures and cholesterol, lower body mass, and lesser skin-fold thickness were found in the living smokers. Blood sugar levels were not different in smokers, ex-smokers, and non-smokers. In the light of the present study, smoking is the factor most increasing the risk of death of malignant tumours and considerably increasing the probability of death of IHD.