See Also: Biography of Barouh Berkovits
The D.C. Defibrillator
The United States Patent Office 3,236,239 DEFIBRILLATOR
Barouh V. Berkovits, Buffalo, N.Y., assignor
to American Optical Company, Southbridge Mass.
Filed July 17, 1962, Ser. No. 210,5947 Claims (Cl. 128-419)
This invention relates to electronic equipment for the treatment of cardiac disorders.
Classic treatment of most cardiac arrythmias involves the use of various drugs, such as quinidine, procainamide, digitalis, and the like. It has been known, also that electrical depolarizing impulses of rather high voltage and amperage can be effective in reverting certain arrythmias to normal sinus rhythm. However, due to the rather high mortality incident to the use of such depolarizing technique, it has heretofore been limited to use in conjunction with terminal events, for example ventricular fibrillation, and even here, usually only in those cases where the classic treatment, open chest cardiac resuscitation, is not indicated. In accord with the present invention, a therapeutic electrical stimulus derived from a charged capacitance is applied in controlled, timed relation to the cardiac cycle, it having been found that the high mortality previously associated with electrical depolarizing is due to application of the depolarizing impulse during one or both of two critical periods during the cardiac cycle. Of primary concern in connection with the present invention, then, is the provision of means enabling a physician to apply a capacitance discharge depolarizing impulse at a selected and precise point during the cardiac cycle which lies outside the above mentioned known critical areas. To achieve this effect, the present invention employs means for detecting the electrical activity of successive cardiac cycles and electrical depolarizing means controllable in timed relation to a known reference point occurring during a cardiac cycle as established from the means for detecting so as to intelligently apply the depolarizing impulse as aforesaid.
| In general, this invention envisages equipment capable of providing electrical stimuli either directly or indirectly to a patient’s heart for the purpose of reverting cardiac arrythmias. FIG. 5 is a waveform showing normal sinus rhythm; FIG. 6 is a waveform showing the output of the trigger synchronized with the R waves of FIG. 5; FIG.7 is a waveform showing the output of the trigger synchronized with the R waveform of FIG. 6. FIG. 8 is a waveform showing the output of the delay means; and FIG. 9 is a waveform showing the output of the defibrillator. |  |
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Demand Pacer
United States Patent Office 3,345,990
Heart-Beat Pacing Apparatus
Barouh V. Berkovits, Tonawanda, N.Y., assignor to
American Optical Company, Southbridge, Mass. a voluntary association of Massachusetts
Filed June 19, 1964, Ser. No. 376,489
9 Claims. (Cl. 128-419)
A heart pacing apparatus which provides electrical heart-stimulating impulses to the patient's heart only in the absence of natural heartbeats. If only a single natural heartbeat is absent only a single electrical impulse will be provided. If more than one natural heartbeat is missing, an equal number of electrical impulses will be provided. No matter how many electrical stimuli are generated, they occur at essentially the same time spacing from each other and from the last natural heartbeat as would be the case if they were all natural heartbeats. The apparatus is arranged normally to generate electrical impulses at pre-determined time intervals approximately the rate of the heartbeat. Upon detection of the natural heartbeat the next electrical stimulus which would otherwise be generated is inhibited. At the same time, the apparatus restarts its timing cycle so that the next electrical impulse will be generated (if needed) after the predetermined time interval has elapsed, starting with the heartbeat just detected. The result is an overall "integrated" operation, i.e., a mutually exclusive cooperation of the natural heartbeats and stimulating pulses.
3,528,428
Heart-Beat Pacing Apparatus
Barouh V. Berkovits, Newton Highlands, Mass.,
assignor to American Optical Company, Southbridge, Mass., a corporation of Delaware
Filed Sept. 15, 1970, Ser. No. 727,129
42 Claims. (Cl. 128-419)
A demand pacer which provides electrical heart-stimulating impulses in the absence of natural heart-beats. In a pacer of this type, if the natural heartbeat detector is erroneously triggered, it is possible for impulses to be inhibited when they are actually needed. Erroneous operation of the detector in the invention is partially prevented by tuning it to the dominant frequencies in the electrical signal which is generated as a result of a localized ventricular depolarization. These frequencies, however, are relatively close to 60 Hz, and thus 60 Hz stray signals might erroneously cut off the generation of impulses. For this reason, a capacitor charging circuit is provided in the detecting circuit. All input signals are processed so that the capacitor is fed by unipolar pulses. Pulses occurring at a 120 Hz rate (from the processing of stray 60 Hz signals) occur so rapidly compared to the discharge time constant of the capacitor circuit that the voltage across the capacitor does not change appreciably. Heartbeat signals, on the other hand, occurring at the much slower rate of approximately 72 per minute, allow the capacitor to discharge sufficiently after each charging pulse such that a large pulsating signal is developed across the capacitor. It is each pulsating signal which shuts off the generation of an impulse. In the presence of 60 Hz stray signals, the pacer functions in its continuous mode.
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Repetitive Firing During Synchronized Electrical Stimulation
Repetitive firing induced by artificial stimuli delivered by commercial (portable or implanted) pacemakers has been considered to be rare in the past. Recent reports suggest that the occurrence of this phenomenon in the human heart is more frequent than previously thought. This potential hazard of synchronized electrical stimulation has been emphasized. The study of other variables, such as the supernormal phase, as well as the analysis of the effects of "strong" driving impulses (15 to 20 times above the threshold) on previously subthreshold responses will be presented in a separate communication. The duration of the absolute refractory period, measured with testing stimulus with an intensity of five times above the threshold, ranged from 265 to 310 msec., for cycle lengths varying between 920 and 1,000 msec. In 6 patients there were spontaneous fluctuations in the length of the refractory period, amounting up to 25 msec. These unexpected effects could not be attributed to variations in the driving rate as happens with those methods of studying excitability which take advantage of the co-action of natural (sino-atrial) and an artificial pacemaker. On the contrary, they could be explained by the movement of the catheter electrode away from the endocardium, although similar variations in refractoriness have also been recorded in experimental studies employing intramyocardial electrodes. The threshold values ranged between 0.6 and 1.5 volts. There were 3 patients in whom repetitive firing occurred in response to impulses falling close to the peak of the T wave.
Castellanos A, Lemberg L, Jude JR, Berkovits BV. Repetitive firing occurring during synchronized electrical stimulation of the heart. J Thorac Cardiovasc Surg 1966; 51: 334-340.
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Demand Pacing
Demand pacemakers function as an artificial automatic fiber with an electronically controlled escape. They stimulate with a preset interval after the preceding ventricular depolarization. This depolarization may be spontaneous or pacemaker induced. When the intrinsic R-R interval is shorter than the escape interval of the pacemaker, the artificial pacemaker remains dormant; similar to an automatic fiber, it continues to be dormant until the interval after a ventricular depolarization is long enough to permit pacemaker escape with resulting stimulation. This stimulation continues with the same escape interval until a spontaneous beat occurs. Thus.in patients with intermittent block, such instruments provide stimulation to the myocardium only when such stimulation is needed, and may even compensate for a single missing beat.
Berkovits B. Ann NY Acad Sci 1969; 167:891-894
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