Three-dimensional vector ECG analysis in the diagnosis of the left anterior fascicular block

The relevance of the study is due to the complexity of the differential diagnosis of left anterior fascicular block (LAFB) with myocardial infarction and left ventricular hypertrophy based on a standard ECG. Aim. Determination of the criteria for LAFB according to the data of three- dimensional vectorcardiography with an analysis of the rate of formation of the vector loop. Material and research methods. The study included 85 patients who underwent a 12-lead ECG study. 2 groups of patients were selected. The main group of 56 patients with LAFB, mean age was 63.3±16.6 (M±δ) years, 34 men and 22 women. The control group included 29 healthy individuals, the mean age was 21.4±2.5 (M± δ) years, 12 men and 17 women. All patients underwent synchronous recording of 12 standard ECG leads in the IS «Unified Cardiologist of the Republic of Tatarstan» and reconstruction of a three-d imensional vectorcardiogram using the McFee-Parungao system with an analysis of the vector loop formation rate using EasyECG Rest ATES Medica software (Russia). Results and conclusions. It is shown that for LAFB the movement of the vector loop counterclockwise is typical in the frontal plane; the presence of 2 extrema, the second is directed upwards, to the right and back. On the graph of the rate of formation of a spatial vector loop, 2 peaks are recorded with a decrease in the rate in the final part of the QRS loop by 2–2.5 times relative to the first peak, which reflects a slowdown in myocardial excitation in the output section of the left ventricle.