It is well known and described in literature that cardiac symptoms such as dyspnoea, palpitations and sometimes stenocardiac pain may develop in the course of anaemia. The incidence of electrocardiographic abnormalities varies significantly in different studies ranging from 10-80%. The study is aimed to determine the incidence of certain electrocardiographic changes in anaemic and non anaemic patients (control group) before and after the stress test. PATIENTS AND METHODS OF EXAMINATION: A total of 60 patients divided in two groups were studied. Group 1 included 30 patients with anaemia, free of cardiorespiratory diseases and normal x ray findings. Control group comprised 30 healthy individuals with normal x ray findings and normal ECG findings at rest, free of anaemia and iron deficiency. The average haemoglobin value in the studied and control group was 85.6 g/L and 127 g/L, respectively. The subjects underwent submaximal ergometric test. The following electrocardiographic parameters were monitored: P wave, PR interval, R amplitude, R difference, ST segment depression, T wave, QT interval and QTc interval.
Results: In the studied group of patients ECG findings revealed ST segment depression at rest in one patient (3%), while in the control group such changes were not recorded. During the stress test, ECG findings revealed ST segment depression in 10 (33%) patients, as well as in 1 (3%) patient of the control group, which proved to be statistically significant. Negative T wave at rest was recorded in no patient of the two groups, while after the stress test ECG findings revealed negative T wave in 3 (10%) patients in the studied group, and in the control group no changes were recorded. Prolonged QT interval was recorded in 8 (27%) patients of the studied group and in 1 (3%) patient of the control group (this finding was considered as statistically significant). The increased R difference was statistically significant and more frequent in the studied group (30%:3%). There were no increased QTc differences in the two groups.
Discussion: The total prevalence of electrocardiographic changes in 30 patients was 64%. The high incidence of electrocardiographic changes of 79% reported by Singh was most probably the result of a larger number of patients with more severe forms of anaemia. There were no cases with sinus tachycardia or sinus bradycardia; no changes in P wave length of PR interval were recorded. Atrial extrasystole, atrial tachycardia and atrial fibrillation (reported by some authors) were nor recorded. ST segment depression at rest occurred in one patient; it was, however, smaller than 1 mm. In 10 (33%) patients ST segment depression was recorded after the stress test. Singh and Volkov reported the similar findings, but in their series significant ST segment depression was also recorded at rest (which is probably due to more severe forms of anaemia). T wave inversion was not recorded at rest, but after the stress test it appeared in 3 (10%) patients. It is reported in the referential literature that approximately 23% of the patients express T wave inversion. Prolonged QT interval was evidenced in 8 (27%) patients, which is consistent with the data reported in literature. The increased R difference by more than 18% which is, according to Stankov, the result of myocardial ischaemia, was statistically more significant in the studied group than in the control group.
Conclusion: Based on the results of the study it may be concluded that the prevalence of ECG abnormalities in patients with anaemia was 63%. As for the individual ECG changes the prevalence of ST segment depression was 33%, T wave inversion 10%, prolonged QT interval 27%, increased R difference 30%. The incidence of ECG abnormalities (ST segment depression and T wave inversion) was markedly higher after the stress test. The recorded electrocardiographic changes may result not only from heart diseases but also from anaemia as a sign of myocardial ischaemia.