The departure index area of departure maps before and after the PTCA procedure was evaluated in 10 randomly chosen patients with clinically significant ischaemic heart disease. The body surface mapping system CARD1AG 128.1, (ZPA Prague-£akovice) was used. The departure index was calculated using Kubota's formula. The departure indexes of the ST-T interval and departure maps of 36 ms and 80 ms intervals from the J point were followed. A decrease of the departure index area was considered as a sign of successful PTCA. A correct classification was made in 6 patients out of 9 (66 %) with successfully performed PTCA. The identification of one patient with unsuccessful PTCA procedure was also correctly determined. The overall correlation between the effect of PTCA and the departure index area change was 7 out of 10 (70 %). The authors consider this method to be a useful non-invasive method for identifying of successful or unsuccessful PTCA in patients with coronary artery disease.
Our previous studies (Valová et al. 1992) have dealt with the possibilities of expert system utilization for electrocardiologic data interpretation. The results obtained in these studies provided evidence that the selected probabilistic expert system is suitable for the solution of VCG data interpretation problems. The aim of this paper was to compare the results obtained by stepwise discriminant analysis with that obtained by a probabilistic expert system. These classification methods were applied to VCG data measured by Frank's lead system. Five groups of patients were investigated: 76 healthy subjects, 36 patients with angina pectoris, 112 patients with old posterior myocardial infarction, 107 patients with old anterior myocardial infarction and 35 patients with old anteroseptal myocardial infarction. The classification was carried out by the leaving-one-out technique. Results of the classification obtained in five groups by a probabilistic expert system are evidently better than those obtained by stepwise discriminant analysis.
After ten years of experience, the authors present an overview of the possible clinical uses of precordial isopotential electrocardiographic mapping in patients with ischaemic heart disease. The resting Q wave and ST segment maps have most often been found useful in the early phases of myocardial infarction. They are a helpful tool for monitoring progression of the disease, the effect of drugs, or the therapeutic effect of fibrinolytic therapy, etc. R wave mapping provides an excellent opportunity for following up patients after orthotopic heart transplantation and monitoring cardiac rejection. Stress tests are usually performed under a workload; alternative loads may be mental, pharmacological, stimulation-induced or under hypoxaemic stress. To evaluate a test, resting values are compared with those obtained during exercise. It is mainly exercise ST segment maps which have proved to be most informative; their use in the chronic phase of ischaemic heart disease helps to make the diagnosis of coronary insufficiency more accurate. In clinical practice, stress tests are recommended mostly in the follow-up of drug therapy, monitoring of the therapeutic effect of cardiac surgery or coronary angioplasty.
Mew possibilities of quantitative evaluation of body surface potential mapping were studied in 78 patients with ischaemic heart disease. Integral maps of the Q wave, QRS and ST-T intervals were plotted and isochronous maps of ventricular activation time and maps of asynchronous potential minima of the Q wave were determined. Minimum and maximum potential values and their time relations were evaluated in the maps. Left ventricular contraction abnormality detected by left ventricular angiography was determined by a point score and expressed as an index of asynergy. The number of coronary artery branches with significant narrowing was assessed and the extent of coronary artery damage was evaluated by an arbitrary defined index. Using quantitative parameters from the maps, multiple stepwise linear regression was performed. The relationship between map parameters and index of asynergy corresponded to multiple correlation coefficient r=0.69 (p=0.01) in the whole group of patients. In the group of patients with left ventricular contraction abnormality the relationship between these parameters was found to be r=0.87 (p=0.01). The relationship between map parameters and the number of coronary artery branches with significant stenosis was r=0.60 (p=0.01) in the group of patients with positive coronary angiography. In the same group of patients the relationship between map parameters and the index evaluating coronary artery damage was equal to r=0.63 (p=0.01). The data obtained from body surface integral maps enable to quantify cardiac ischaemic damage.