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Ventricular Fibrillation Induced by a Defective Demand Pacemaker

1976; Elsevier BV; Volume: 69; Issue: 2 Linguagem: Inglês

10.1378/chest.69.2.247

1931-3543

Raúl Chirife, William S. Frankl, Rolando Mendizabal, Manuel R. Estioko,

Neurological disorders and treatments

To the Editor:Although the occurrence of pacemaker-induced tachycardia or so-called “runaway” pacemakers is a rare event due to the modern design of pacemakers, it still may occur and has been seen in some pacemakers manufactured around 1972. The case we report here is that of a patient who, upon admission to the hospital, presented with a pacemaker rate of 210 beats per minute, which increased to 2,000 beats per minute within five minutes, followed by loss of capture and ventricular fibrillation.CASE REPORTA 44-year-old man with congenital heart block had a unipolar pacemaker implanted in February 1973 in another hospital. A few months after implantation, the patient developed pain and fluid accumulation in the generator pocket. These symptoms were treated conservatively, and the patient did fairly well until about four days prior to admission, when he first noticed palpitations.On the morning of admission, the patient noted lightheadedness and again complained of palpitations, for which he consulted a nurse at his place of employment. His rate was noted to be extremely rapid, and the patient was transferred to our hospital. Upon arrival, the patient was anxious, cold, and clammy with a systolic blood pressure of 70 mm Hg. The pulse was thready. An electrocardiogram revealed an artificial pacemaker rhythm at a rate of 210 beats per minute with 1:1 ventricular response, which did not respond to chest stimulation to overdrive it. At this point the patient was transferred immediately to the operating room, and while his chest was being prepared for pacemaker removal, the pacemaker rate increased to 2,000 beats per minute with loss of ventricular capture (Fig 1).Immediately thereafter, the cardiac monitor revealed ventricular fibrillation. While cardiopulmonary resuscitation was taking place, the pacemaker generator was removed, and the wires were disconnected and attached to an external pulse generator, with persistence of the ventricular fibrillation. At the third attempt at electrical cardioversion, the patient reverted to his underlying rhythm of third-degree atrioventricular block. This rhythm was easily captured by an external generator until a new permanent unit was implanted shortly thereafter. The patient recovered uneventfully. The failing pacemaker was a Biotronik model IDP44 (serial number, 56358). It was noted to have a red oxide in various areas of the seam of the metal case, with evidence of leakage at these points manifested by the formation of a crust.DISCUSSIONAlthough the occurrence of runaway pacemakers is a rare event in recent years, it is still a condition which should be considered when patients who have permanent artificial pacemakers complain of palpitations or when any rate increase is noticed on followup visits. Runaway pacemakers show an increase in rate to very fast levels in a relatively short period of time, as was noted in this case. This mode of failure is associated with a very high mortality, which has been reported to be between 24 and 50 percent.1Harper R Peter T Hunt D et al.Runaway pacemaker rhythm after 36 hours of electrical inactivity.Br Heart J. 1974; 36: 610Crossref PubMed Scopus (9) Google Scholar, 2Furman S Escher DJW Solomon N Experiences with myocardial and transvenous implanted cardiac pacemakers.Am J Cardiol. 1969; 23: 66-72Abstract Full Text PDF PubMed Scopus (42) Google Scholar, 3Ector H Stroobandt R Lemmens A et al.Successful treatment of pacemaker-induced ventricular fibrillation.Chest. 1974; 66: 733-734Crossref PubMed Scopus (9) Google Scholar According to the manufacturer of this particular pacemaker, the catalyst used to harden the epoxy resins used for encapsulation of the units proved to be defective, allowing leakage of body fluids through the defective epoxy resins into the circuitry. Another postulated mode of malfunction in this case is the swelling of the epoxy resin due to this leakage, with consequent breakage of some electronic components.Pacemakers from another manufacturer (Cordis Corp., written communication, December 1974) also showed evidence of excessive moisture penetration through the epoxy encapsulation, but apparently the only abnormality noted so far is the progressive slowing of the paced rate and we are not aware of pacemaker tachycardia occurring in units manufactured by this company. In another instance (Food and Drug Administration recalls T-119-5 to T-122-5, T-133-5 to T-137-5, and T-163-5), pacemaker-induced tachycardia was produced by electrolytic leakage from the batteries. All of these problems have already been corrected by the manufacturers for the new units.We, therefore, strongly recommend that pacemaker-regulated patients who complain of palpitations should be immediately examined for the possibility of pacemaker-induced tachycardia and that any documented rate increase, although minimal, should raise the suspicion of this condition and cause the generator to be replaced immediately. To the Editor: Although the occurrence of pacemaker-induced tachycardia or so-called “runaway” pacemakers is a rare event due to the modern design of pacemakers, it still may occur and has been seen in some pacemakers manufactured around 1972. The case we report here is that of a patient who, upon admission to the hospital, presented with a pacemaker rate of 210 beats per minute, which increased to 2,000 beats per minute within five minutes, followed by loss of capture and ventricular fibrillation. CASE REPORTA 44-year-old man with congenital heart block had a unipolar pacemaker implanted in February 1973 in another hospital. A few months after implantation, the patient developed pain and fluid accumulation in the generator pocket. These symptoms were treated conservatively, and the patient did fairly well until about four days prior to admission, when he first noticed palpitations.On the morning of admission, the patient noted lightheadedness and again complained of palpitations, for which he consulted a nurse at his place of employment. His rate was noted to be extremely rapid, and the patient was transferred to our hospital. Upon arrival, the patient was anxious, cold, and clammy with a systolic blood pressure of 70 mm Hg. The pulse was thready. An electrocardiogram revealed an artificial pacemaker rhythm at a rate of 210 beats per minute with 1:1 ventricular response, which did not respond to chest stimulation to overdrive it. At this point the patient was transferred immediately to the operating room, and while his chest was being prepared for pacemaker removal, the pacemaker rate increased to 2,000 beats per minute with loss of ventricular capture (Fig 1).Immediately thereafter, the cardiac monitor revealed ventricular fibrillation. While cardiopulmonary resuscitation was taking place, the pacemaker generator was removed, and the wires were disconnected and attached to an external pulse generator, with persistence of the ventricular fibrillation. At the third attempt at electrical cardioversion, the patient reverted to his underlying rhythm of third-degree atrioventricular block. This rhythm was easily captured by an external generator until a new permanent unit was implanted shortly thereafter. The patient recovered uneventfully. The failing pacemaker was a Biotronik model IDP44 (serial number, 56358). It was noted to have a red oxide in various areas of the seam of the metal case, with evidence of leakage at these points manifested by the formation of a crust. A 44-year-old man with congenital heart block had a unipolar pacemaker implanted in February 1973 in another hospital. A few months after implantation, the patient developed pain and fluid accumulation in the generator pocket. These symptoms were treated conservatively, and the patient did fairly well until about four days prior to admission, when he first noticed palpitations. On the morning of admission, the patient noted lightheadedness and again complained of palpitations, for which he consulted a nurse at his place of employment. His rate was noted to be extremely rapid, and the patient was transferred to our hospital. Upon arrival, the patient was anxious, cold, and clammy with a systolic blood pressure of 70 mm Hg. The pulse was thready. An electrocardiogram revealed an artificial pacemaker rhythm at a rate of 210 beats per minute with 1:1 ventricular response, which did not respond to chest stimulation to overdrive it. At this point the patient was transferred immediately to the operating room, and while his chest was being prepared for pacemaker removal, the pacemaker rate increased to 2,000 beats per minute with loss of ventricular capture (Fig 1). Immediately thereafter, the cardiac monitor revealed ventricular fibrillation. While cardiopulmonary resuscitation was taking place, the pacemaker generator was removed, and the wires were disconnected and attached to an external pulse generator, with persistence of the ventricular fibrillation. At the third attempt at electrical cardioversion, the patient reverted to his underlying rhythm of third-degree atrioventricular block. This rhythm was easily captured by an external generator until a new permanent unit was implanted shortly thereafter. The patient recovered uneventfully. The failing pacemaker was a Biotronik model IDP44 (serial number, 56358). It was noted to have a red oxide in various areas of the seam of the metal case, with evidence of leakage at these points manifested by the formation of a crust. DISCUSSIONAlthough the occurrence of runaway pacemakers is a rare event in recent years, it is still a condition which should be considered when patients who have permanent artificial pacemakers complain of palpitations or when any rate increase is noticed on followup visits. Runaway pacemakers show an increase in rate to very fast levels in a relatively short period of time, as was noted in this case. This mode of failure is associated with a very high mortality, which has been reported to be between 24 and 50 percent.1Harper R Peter T Hunt D et al.Runaway pacemaker rhythm after 36 hours of electrical inactivity.Br Heart J. 1974; 36: 610Crossref PubMed Scopus (9) Google Scholar, 2Furman S Escher DJW Solomon N Experiences with myocardial and transvenous implanted cardiac pacemakers.Am J Cardiol. 1969; 23: 66-72Abstract Full Text PDF PubMed Scopus (42) Google Scholar, 3Ector H Stroobandt R Lemmens A et al.Successful treatment of pacemaker-induced ventricular fibrillation.Chest. 1974; 66: 733-734Crossref PubMed Scopus (9) Google Scholar According to the manufacturer of this particular pacemaker, the catalyst used to harden the epoxy resins used for encapsulation of the units proved to be defective, allowing leakage of body fluids through the defective epoxy resins into the circuitry. Another postulated mode of malfunction in this case is the swelling of the epoxy resin due to this leakage, with consequent breakage of some electronic components.Pacemakers from another manufacturer (Cordis Corp., written communication, December 1974) also showed evidence of excessive moisture penetration through the epoxy encapsulation, but apparently the only abnormality noted so far is the progressive slowing of the paced rate and we are not aware of pacemaker tachycardia occurring in units manufactured by this company. In another instance (Food and Drug Administration recalls T-119-5 to T-122-5, T-133-5 to T-137-5, and T-163-5), pacemaker-induced tachycardia was produced by electrolytic leakage from the batteries. All of these problems have already been corrected by the manufacturers for the new units.We, therefore, strongly recommend that pacemaker-regulated patients who complain of palpitations should be immediately examined for the possibility of pacemaker-induced tachycardia and that any documented rate increase, although minimal, should raise the suspicion of this condition and cause the generator to be replaced immediately. Although the occurrence of runaway pacemakers is a rare event in recent years, it is still a condition which should be considered when patients who have permanent artificial pacemakers complain of palpitations or when any rate increase is noticed on followup visits. Runaway pacemakers show an increase in rate to very fast levels in a relatively short period of time, as was noted in this case. This mode of failure is associated with a very high mortality, which has been reported to be between 24 and 50 percent.1Harper R Peter T Hunt D et al.Runaway pacemaker rhythm after 36 hours of electrical inactivity.Br Heart J. 1974; 36: 610Crossref PubMed Scopus (9) Google Scholar, 2Furman S Escher DJW Solomon N Experiences with myocardial and transvenous implanted cardiac pacemakers.Am J Cardiol. 1969; 23: 66-72Abstract Full Text PDF PubMed Scopus (42) Google Scholar, 3Ector H Stroobandt R Lemmens A et al.Successful treatment of pacemaker-induced ventricular fibrillation.Chest. 1974; 66: 733-734Crossref PubMed Scopus (9) Google Scholar According to the manufacturer of this particular pacemaker, the catalyst used to harden the epoxy resins used for encapsulation of the units proved to be defective, allowing leakage of body fluids through the defective epoxy resins into the circuitry. Another postulated mode of malfunction in this case is the swelling of the epoxy resin due to this leakage, with consequent breakage of some electronic components. Pacemakers from another manufacturer (Cordis Corp., written communication, December 1974) also showed evidence of excessive moisture penetration through the epoxy encapsulation, but apparently the only abnormality noted so far is the progressive slowing of the paced rate and we are not aware of pacemaker tachycardia occurring in units manufactured by this company. In another instance (Food and Drug Administration recalls T-119-5 to T-122-5, T-133-5 to T-137-5, and T-163-5), pacemaker-induced tachycardia was produced by electrolytic leakage from the batteries. All of these problems have already been corrected by the manufacturers for the new units. We, therefore, strongly recommend that pacemaker-regulated patients who complain of palpitations should be immediately examined for the possibility of pacemaker-induced tachycardia and that any documented rate increase, although minimal, should raise the suspicion of this condition and cause the generator to be replaced immediately.