The epicardial breakthrough can be recognized from the localized lowering of the body surface potential, which is characterized by a concave figure of the equipotential lines or a second-minimum on the isopotential maps. Recognition of epicardial breakthrough enables us to diagnose location of the block site of the bundle branch blocks more precisely than by the use of ECG or VCG. However, it has not been determined as to how long an interelectrode distance is appropriate to detect such a localized potential. In the present study, influence of the interelectrode distance on the characteristic patterns reflecting the epicardial breakthrough was examined with respect to 16 healthy persons by using three kinds of 9 x9 array electrode with interelectrode distances of 1.25 cm, 5×5 with 2.5 cm, 3×3 with 5 cm, respectively.
Breakthrough was recognized in 15 out of 16 cases (94%) on maps recorded with electrode arrays at interelectrode distances of 1.25 cm and 2.5 cm. However, it was possible to recognize the breakthrough in only 10 out of 16 cases (63%) with the electrode array at the interelectrode distance of 5 cm.
Conclusion It is prefarable to use electrode arrays within interelectrode distance of at least 2.5 cm for purposes of the breakthrough recognition.
