gms | German Medical Science

Ventricular activation time (VAT) can be assessed with isochrone maps obtained from the multielectrode registration system. A purpose of the study was to analyze VAT characteristics in patients with left bundle branch block (LBBB). A study group consisted of 24 patients with LBBB, diagnosed on the 12-lead ECG, and a control group of 30 healthy subjects. Recordings of body surface potential mapping (BSPM) were performed with 87-lead Fukuda Denshi system. Isochrone maps were created with the original software and the pattern maps were established using discriminative analysis. Isochrone maps served for determining an activation propagation pathway, including velocity alteration. In the isochrone maps, the ventricular activation onset in complete LBBB, like in the controls, occurred over anterior torso at 12. ms. Then, the isochrones moved from the medial anterior line toward the upper parasternal left line and leftward to the middle portion of the left midclavicular line. Next, the isochrones extended downward and toward left midaxillary line, then covered the back and reached right axillary line. After that, the isochrones migrated to the anterior left thorax and finally gained a stability at 90-95. ms near anterior left axillary line. In complete LBBB, the first isochrone in the group-mean VAT map was observed in the middle zone of the anterior torso and had a value of 12 ms, whereas the last isochrone, at the anterior left axillary line, had a value of 95 ms. Analysis of the isochrones distribution between the terminal time instants enabled a precise monitoring of the activation process trajectory within the ventricles. Comparison of the VAT maps obtained from the patients with LBBB and the controls revealed the significant time data differences, which appeared to be of discriminative value. The established distribution patterns and values matrixes of the VAT maps could be applied for extended LBBB diagnosing.