The American journal of cardiology
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A prospective study of a computerized arrhythmia alarm system was carried out in the coronary care unit during 200 patient hours of monitoring. The computer system was designed to activate an alarm on the development of rhythm and conduction disorders including asystole, ventricular tachycardia, atrial tachycardia, sinus tachtcardia, bradycardia, frequent premature ventricular beats, atrial fibrillation and bundle branch block. Study patients were simultaneously monitored by the computer system and a conventional analog heart rate alarm system. ⋯ Of 79 computer alarms, 42 (53 percent) were true positive alarms; during the same period there were 167 analog alarms of which only 13 (8 percent) were true positive alarms. In both systems, false positive alarms were primarily due to patient movement, but they occurred only 25 percent as often with the computer system as with the analog system. These results indicate that computerized arrhythmia monitoring systems offer significant advantages over conventional monitoring techniques.
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Anomalous origin of the left coronary artery from the pulmonary artery is a rare and usually fatal congenital malformation. Most surgical attempts to correct this anomaly have been unsuccessful, particularly those in infants. ⋯ This technique of reimplantation of the aberrant vessel into the aorta appears to be prefereble to other methods of repair, especially since it can be applied in any patient with the anomaly regardless of age or size. Because of the poor prognosis for patients with anomalous left coronary artery, surgical intervention should be made as soon as the diagnosis is made.
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At the time of initial balloon atrial septostomy a patent ductus arteriosus was found with angiography in 39 of 81 infants with transposition of the great arteries with intact ventricular septum. By angiographic criteria the ductus shunt was considered small in 21 infants and large and significant in 18. In contrast to the usual clinical presentation of neonates with transposition and intact ventricular septum, 12 of these 18 infants with a significant patent ductus arteriosus had only slight cyanosis and 8 presented with tachypnea out of proportion to the degree of cyanosis. ⋯ Acute early narrowing or closure, spontaneous (six infants) or surgically produced (three infants), occurred usually within the 1st month of life and was associated with a marked decrease in arterial oxygen saturation in eight infants, often with a rapid clinical deterioration. Persistence of a large patent ductus arteriosus for several months appears to be associated with an increased incidence of early pulmonary vascular disease. Therapeutic considerations for the infant with a large patent ductus arteriosus after initial balloon atrial septostomy include: (1) careful initial follow-up of the infant in clinically stable condition in case the ductus arteriosus should acutely narrow or close and the patient require urgent palliative or corrective surgery; (2) urgent early closure of the ductus in the infant with overt left heart failure with concurrent atrial septectomy or preferably primary corrective surgery; and (3) elective closure of a persistent significant patent ductus arteriosus before age 4 months with concurrent corrective surgery in the infant in clinically stable condition.
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Eleven percent of 905 consecutive patients with acute myocardial infarction admitted to the coronary care unit at Duke University Medical Center experienced cardiac arrest. Subgroups of patients at high and low risk for cardiac arrest were identified. Cardiac arrest was experienced by 17 percent of patients with signs of heart failure on admission but by only 3 percent of patients without diabetes mellitus, prior myocardial infarction or heart failure by history or on admission. ⋯ Among 668 hospital survivors who had mild or no heart failure during hospitalization, cardiac arrest continued to be a significant predictor of mortality. The mode of death among hospital survivors did not differ in the groups with and without cardiac arrest; for example, the incidence rate of sudden death in the two groups was 44 and 37 per cent, respectively. In light of recent reports suggesting that the prophylactic use of antiarrhythmic agents can virtually eliminate virtually fibrillation during the hospital phase of acute myocardial infarction, we contend that such use may substantially reduce both long-term and hospital mortality after acute myocardial infarction.
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Tests were conducted on rechargeable mercury-zinc pacemaker batteries under simulated and actual biologic conditions, using a variety of discharge rates and charging schedules. In tests on 96 cells at a 6.4 milliampere (ma) discharge, recharging once every 15 months of simulated pacing at a 25 microampere (mua) drain, the earliest cell failure occurred after an equivalent of 50 years of pacing. The mean pacing equivalent for all 96 cells was more than 140 years. ⋯ Seven other cells at a 200 mua drain with periodic recharging continue to function normally after more than 7 years of actual time, simulating 56 years of pacing at a 25 mua drain. Cardiac pacemakers using the rechargeable mercury-zinc cell have been implanted in animals for more than 2 1/2 years and in patients for more than 1 year with all units continuing to function satisfactorily. It has been demonstrated unequivocally that a rechargeable mercury-zinc pacemaker will function continuously for more than 4 years without recharging and that periodic recharging will extend pacing life far beyond that predicted for lithium and nuclear primary power sources.