Cavity potentials of the human ventricles.

Intracavitary potentials of the human left ventricle were studied in 8 patients by the technic of retrograde ulnar artery or, in one case, pulmonary vein catheterization. The intracavitary potentials from the left ventricle were of the QS variety and confirm Wilson's concept of the earlier de-polarization of the intraventricular septum from left to right. IN RECENT years the genesis of the human electrocardiogram has been clarified as a result of catheterization of the right side of the heart.' The fundamental concepts of Wilson and others, based upon dog experiments , have been amply substantiated in practically all respects. How-err, in man, proof of the earlier depolarization of the left side of the upper part of the interventricular septum has been based upon the demonstration of an R wave in the right ventricular cavity, and upon the assumption that an lR wave would be absent in the corresponding region of the left ventricular cavity. The answer to this problem is now afforded by electrocardiograms obtained from the cavity of the human left ventricle by the technic of left heart catheterization.2 The first left ventricle catheterization was done on October 8, 1948. METHODS The intracavitary potentials of the left ventricle of 9 male patients were obtained, 8 by the tech-nic of retrograde ulnar arterial catheterization,' and one by passing a catheter electrode through a pulmonary vein into the cavity of the left ventricle at the time of operation for pneumonectomy. In 5 of 8 patients, the right ventricle was also catheter-ized in the usual fashion' at the same time and intracavitary electrocardiograms recorded. The San-born Viso-Cardiette and Stetho-Cardiette were used to record the electrocardiograms. To avoid damaging the aortic valve leaflets, patients with functional and organic insufficiency of the aortic valve were selected for retrograde ulnar arterial catheterization. Earlier attempts to bypass the normal aortic valve were uniformly unsuccessful .4 In 6 patients, the aortic insufficiency was of syphilitic origin, and in 2 hypertensive patients there was functional aortic valvular insufficiency presumably due to dilatation of the aortic ring. There was an average pulse pressure of 98 mm. Hg, and the usual auscultatory and dynamic signs of aortic insufficiency were plresent. The patients ranged in age from 48 to 74 years. Only 2 were on digitalis therapy. Safety plrecautions included ample sedation and continuous observation of the cardiac mechanism by means of a direct writing electro-cardiograph during the procedure. The patients withstood …