The Zero of Potential of the Electrical Field Produced by the Heart Beat

Abstract

The zero of potential of the electrical field produced by the heart beat is defined and measured as the average value over the surface of a large spherical, integrating electrode which contains the subject and a homogeneous conducting medium. The zero of potential thus defined is apparently free of assumptions of any kind and is used to evaluate the error on the three-branch and the fourbranch central terminal with equal resistances. The latter may, in certain instances, be brought to zero by using unequal resistances. The potential function at its electrodes is that of an unweighted resultant vector or a point dipole. The electrodes which contribute to its potential are remote Wherein V p is the arbitrary-dipole function for the sphere; Si is the spherical surface of a large integrating electrode (fig. 1); and V p , the average value of V p , is independent of the position of the dipole distribution within Si and is zero. Si has a radius of three feet and consists of a copper screen held in the form of a spherical surface by an exterior wood frame. An electrical hoist lowers Si into a tank containing tap water. The dipole distribution consisted of a six-pole generating electrode by which one, two, or three electromotive forces were impressed upon the volume conductor and by which the field axis was rotated in three or more noncoplanar directions. The surface Si contained several nonhomogeneous structures, From the Department of Internal Medicine, University of Oklahoma School of Medicine, Oklahoma City, Okla.Presented in part at the Twenty-Fourth Annual Postgraduate Symposium of the San Francisco Heart Association, Oct. 28, 1953. These investigations were supported by grants from the National Heart Institute of the Xational Institutes of Health, Public Health Service.Received for publication July 2S, 1953. the seat suspension, breathing tubes, face mask, contact microphones, and wire leads. Equation 1 is based on the assumption that the conducting medium within Si is homogeneous and that Ri the radius of Si, is of any value that permits Si to contain the dipole distribution. The magnitude of Ri for Si was based, however, on the idea of placing the living human subject interior to Si, figure 1. Upon immersion the potential Vo of Si must assume a value sufficiently close to the zero of the potential of the field produced by the heart beat to permit accurate evaluation of the potential at electrodes on the body surface, particularly those electrodes which are utilized with a central terminal of the Wilson type.The living human subject is a nonhomogeneous volume conductor of irregular closed surface S 2 which contains an arbitrary dipole distribution. Upon immersion a homogeneous medium (tap water) exists between the body surface S 2 and the surface »Si of the spherical integrating electrode. The field of the heart beat now extends throughout the conducting medium exterior to Si. A Helmholtz double-layer on S 2 when acting alone will produce an electrical field between Si and S 2 identical to that which is act...

True Unipolar ECG Machine for Wilson Central Terminal Measurements

“…We recall that amplitudes for the WCT of the order of 0.2 mV were already measured during a historical experiment that made use of a cumbersome procedure. During the experiment a volunteer was immersed in water whilst being encased in a metal structure called an “integrator electrode” [ 15 , 16 , 18 , 35 ]. Our device instead allows continuous WCT precise measurement by recording straight from the limb electrodes.…”

“…Confirmation of errors and variability of the WCT during the cardiac cycle have been measured employing an “integrator electrode.” This procedure requires the entire human body to be encased in a metal structure and then immersed in water (neutral reference) during the measurement of ECG. Unfortunately, due to the cumbersomeness of the measurement process, this technique was used only for few experimental trials [ 15 , 16 ]. In recent years, the significance of the WCT and even its physical location has also been debated [ 9 , 10 , 17 ].…”

On the Einthoven Triangle: A Critical Analysis of the Single Rotating Dipole Hypothesis

“…Before delving into the full explanation of our method, we must mention that Wilson’s hypothesis and the related triangle to star transformation has been challenged at both the theoretical [ 8 , 9 , 10 , 11 , 12 , 13 ] and practical level [ 2 , 3 , 6 , 10 , 11 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ] several times in the past 80 years, with several researchers confirming that, contrary to what Wilson’s principal postulates [ 1 , 22 , 23 ], the amplitude of the WCT can be comparable to (or even larger than) the limb leads, and can exhibit variability during the cardiac cycle similar to any other ECG signal [ 2 , 8 , 10 , 16 , 24 , 25 , 26 , 27 , 28 ]. Still, as already mentioned, one may note that the original instrument that both Einthoven and Wilson used to formalize the triangular ECG model and the WCT was measuring the current impressed by the heart to the body surface, while modern electrocardiography uses voltage amplifiers [ 28 ].…”

Minimization of the Wilson’s Central Terminal voltage potential via a genetic algorithm

“…Similarly to previous studies [9, 10], the WCT and M-WCT amplitudes are measured averaging five consecutive beats for each dataset and reported as a percentage of lead II. We used the orientation of the QRS complex to report the polarity of the WCT.…”

“…Following this recommendation, Bayley and Kinard [9, 10] encased the body of volunteers inside a metal structure (called integrator electrode) that was immersed in water for the duration of the recording. With this experiment, they determined that the WCT is non-stationary during the cardiac cycle and its amplitude could be as large as 40% of Einthoven’s ECG signals [9, 10]. During this experiment, Bayley and Kinard also attempted a real-time minimization of the WCT amplitude to bring it below a non-influent value [10].…”