心室期外収縮の実験的研究

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Because the ventricular extrasystole is highest frequency amongst all the arrhythmias and it gives bizaare QRS configuration, the process of the intraventricular spread of the excitation in this condition has been extensively studied. While Burdon-Sanderson insisted that the activation wave spread out in all directions uniformly, Lewis and sub-sequent investigators found that the special conduction system was involved in the activation wave in this condition. However, opinions of different investigators are not necessarily in agreement in minute details and much has remains ambiguous. Furthermore, most of the past studies depended on the direct unipolar lead, i.e., the process of propagation of the activation wave being estimated on the ground of the measurement of the impulse arrival time at different points. No study of this process has yet been attempted with vector-cardiographic techniques. The author studied the process of the intraventricular spread of activation wave in experimentally produced ventricular extrasystoles, employing the vectorial lead method developed by Prof. Takayasu on the basis of the lead field theory of McFee and Johnston. Method s A perfused heart was placed within a vessel filled with a volume conductor, Ringer-Locke solution, and in the mid-point between a pair of plates having about the same area as the largest cross section of the heart ; in this method of bipolar lead, the circuit connection was made in such a way that the relative positivity of the electrode facing the left side or anterior side of the heart might cause an upward deflection along the X or Z axis, respectively. Multiple direct unipolar leads were obtained by applying many terminals (tips of insulated copper wires) to the free wall of both ventricles (both endocardial and epicardial surface) and to the surface of the septum. Extrasystoles were produced by driving negative, rectangular waves of electrical stimulus at intervals of 300-700msec. and with the minimum effective intensity. As to the electrocardiographic recording, the vectorial lead was recorded first, simultaneous recording of vectorial lead (X-axis) and the direct unipolar leads was recorded next. Similar ECG recording was done after the section of bundle branch, and the results were compared. Results, Discussion and Summary No matter which site of the free wall or septum may be stimulated, the observed vectorial lead configuration of ventricular extrasytoles was composed of two elements, (1) one element of relatively mild steepness in stimulation of anterior subdivision of bundle branch and (2) the other one of very steepness in posterior subdivision. Moreover the anterior subdivision configuration could be divided into 3 parts, (a) part A which is practically a plateau, (b) part B, forming a mild slope and (c) part C, a relatively steep curve. Comparison of patterns of the vectorial lead and direct unipolar leads revealed the location represented by the various components observd ; with regard to the above-mentioned part A represents the immediate vicinity of the stimulated point, part B represents a region relatively near the stimulated point, and
社団法人日本循環器学会の論文
1961-10-15

心室期外収縮の実験的研究

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