See Also:Biography of Paul Zoll
Zoll - Electrodyne Implanted Pacemaker
The table depicts Drs. Zoll and Frank's four-year experience with implanted pacemakers. They analyzed 103 patients grouped in three phases of surgical/technological development. There was one advance in pacemaker/model and two advances in electrode design. The pacemaker mode was VOO without capacity for rate or any other adjustment. The factory rate was set at 70 or 75 bpm. The authors addressed alternative technology such as rate adjustability, maintaining atrio-ventricular sequencing, potential problems created by competitive ventricular pacing (R on T phenomenon), controlling heart action during the operative procedures prior to placement of the fully implantable unit and self contained power sources versus rechargeable power sources. The Electrodyne manufactured pacemaker is depicted. In a published discussion which followed the presentation of this paper, Dr. Elliot S. Hurwitt commented that Dr. Seymour Furman had satisfactorily managed 82 patients with severe heart block with temporary transvenous pacemakers and an external pulse generator. Dr. Hurwitt commented that he believed that the catheter pacemaker was the preferred approach to temporarily maintain a patient awaiting a permanent pacemaker and for control during anesthesia and operation. In regard to each of the aforementioned issues, Drs. Zoll and Frank opted for simplicity, security and instrument longevity. In time, each of the innovations discussed gained full acceptance except for the rechargeable battery.
Table 1: Electrical Failure and Sepsis
| Period of
Implantation | Pacemaker
Unit | Electrodes
and Wires | Number of
Patients
in Each
Phase* | Patients with Pace-
maker Failure | Patients with
Wire or Electrode Break | Patients with Sepsis |
| July 1960–May 1961 | Early (metal-encased) | Platinum-solid | 12 | 4 | 3 | 4 |
| June 1961–March 1962 | | | 23 | 1 | 11 | 2 |
| April 1962–September 1963 | Present (epoxy-
encased) | Platinum-plated
49-strand wires | 44 | 0 | 6 | 0 |
| September 1963–April 1964 | | Platinum-plated
77-strand wires | 24 | 0 | 0 | 1 |
*26 patients in more than one phase of the method.
Zoll PM, Frank HA, Linenthal AJ. Four-year Experience with an Implantable Cardiac Pacemaker. Annals of Surgery 1964; 160: 351-365. Back to Top
An Individual Implant History
Paul Zoll deservedly had a premier reputation as a clinical cardiologist and developed a strong bond with his pacemaker patients. He and Howard Frank were constantly available, avoiding vacations, so that patients would travel long distances, on short notice, to return to their care. He often stated that it was the patients and their problems who energized his work in the laboratory. The table depicts sequential pacemaker procedures in a man from the Midwest with Stokes-Adams attacks. After the second pacemaker implantation failed, he was referred to the care of Paul Zoll and Howard Frank who directed his care from 1964 until their retirement. Frank performed 13 operative procedures with Zoll assisting at each to maintain a continuous effective heart rate. The evolution of pacemaker and electrode technology is evident with ultimate realization of reliability and longevity. Although the patient's residence remained in the Midwest, the bond with Zoll and Frank caused him to return to Boston for each pacemaker procedure including the last which was performed by their former trainees. The patient has survived almost 38 years with cardiac pacing.
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Cardiac Monitor Pacemaker
Early recognition and a rapid prearranged response to life-threatening arrhythmias was Dr. Zoll's constant theme. He and Alan Belgard, his engineer, developed oscilloscopic continuous cardiac monitors which visually and audibly recorded cardiac activity and alarmed when predetermined rate limits were violated. Some of their machines were capable of automatically externally pacing the asystolic or extremely bradycardic patient. In time, the monitors had a hard copy ECG printout and retrievable memory. Dr. Zoll's monitors, transthoracic pacemakers, and transthoracic defibrillators were essentially prerequisites for the early coronary care units.
Nicholson MJ, Orr RB, Eversole UH, Crehan JP. A cardiac monitor-pacemaker: Use during and after anesthesia. Anesthesia and Analgesia. 1969; 38: 355-347.
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Wolf Creek Conference on Cardiopulmonary Resuscitation
"The science of resuscitation stems from the demonstration of Zoll and others that the human heart can be defibrillated by a shock administered across the chest."* Zoll's primary research and clinical interests were in managing heart disease with the potential for arrhythmic crisis. he developed algorithms to resuscitate and stabilize these hearts. His works provided the platform for Advanced Cardio-Pulmonary Resuscitation. Zoll was a recognized expert in these matters. As a member of Boston's Beth Israel Hospital's Resuscitation Committee, he responded to many in-house cardiac arrests. He was the Chairman of the Massachusetts Heart Association's Committee on Cardiac Arrest, published on the subject, and participated in national programs on cardiopulmonary collapse. Zoll was among the "first generation" of resuscitation researchers at the first Wolf Creek Conference on cardiopulmonary resuscitation which was a think tank for the initiators of modern CPR.
*Kravitz AE, Killip R. Cardiopulmonary resuscitation status report. NEJM 1972;286:1000-1001.
Zoll PM, Linenthal AJ. External and internal electric cardiac pacemakers. Circulation 1963;28:455-466. Back to Top
Mechanical Cardiac Stimulation
While cardiologist and Chief of Medicine at the U.S. Army Station Hospital, United Kingdom, Zoll observed Dr. Dwight Harken extract bullets, shrapnel and shell fragments from in and about the heart. He noted that the mere contact of a finger or a medical instrument to the surface of the heart evoked a cardiac contraction. He later incorporated the principle of the mechanical stimulus, such as a chest thump or repetitive chest thumps, to cause an asystolic heart in cardiac standstill arrest to beat into an external mechanical cardiac stimulator which could deliver a mechanical precordial chest thump timed to the nonvulnerable phase of the cardiac cycle. Ten human subjects were used in his trial. The thump evoked an electrical stimulus in eight of ten. The experience was somewhat unpleasant for all conscious patients and was tolerated without complaint in four patients. Zoll hoped that the "mechanical pacemaker" would provide a noninvasive means of stimulating a heart during an emergency or for any purpose. In a moment of reflection, Zoll recalled showing the prototype model to an engineer patient who offered to restructure the prototype. Modification was made in one day. The modified model was returned one week later. The prototype had taken years to develop. The engineer-patient's offer was "straight from the goodness of his heart." The external mechanical cardiac stimulator has also been used in clinical experimentation with idiopathic hypertrophic subaortic stenosis.
Zoll PM, Belgard AH, Weintraub MJ, Frank HA. New Eng J Med 1978; 294: 1274-1275.
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