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Halperin J L - - 1984
Skeletal myopotentials may inhibit the output of unipolar demand ventricular pacemakers, resulting in protracted episodes of asystole in susceptible patients. The new DDD-mode pacemakers have, in addition to a unipolar ventricular lead, a unipolar atrial lead to enable atrioventricular sequential or atrial synchronous function. During clinical investigation of a new ...
Loperfido F - - 1984
Multiform ventricular ectopic rhythm (MVER), i.e., at least two QRS configurations of ventricular ectopic beats (VEBs), was assessed by 24-hour ambulatory ECG recording in four patients with ventricular parasystole (VP). In two of these four patients, VEBs with fixed coupling to the preceding impulses coexisted with VP beats of different ...
Shahinian L L - - 1984
A scalloped line of tear film thinning (corneal valance), running horizontally across the top third of the cornea, was readily seen with slit lamp, fluorescein, and blue filter in 25 patients. Careful retrospective examination of these patients revealed barely discernible map and fingerprint lines corresponding to the areas of tear ...
Parsonnet V - - 1984
From the outset, the art and science of cardiac pacing has been beset with a variety of problems. With the passage of time and concentrated effort in the interrelated sciences, many have been solved. We no longer are concerned with premature battery failure or leaking pulse-generator capsules, but now focus ...
Harries M G - - 1984
A patient in whom a severe systemic illness was characterised by weight loss, arthralgia and breathlessness was exposed to her pet bird. This pragmatic approach reproduced the features of her illness. The changes that occurred in her pulmonary physiology and histology differed from those seen in extrinsic allergic alveolitis in ...
Samarel A M - - 1984
Rabbit cardiac cathepsin D exists as multiple isomeric forms of Mr = 48,000 within cardiac tissue. Their mechanism of formation and their functional role in cardiac protein degradation are unknown. We have previously demonstrated that cathepsin D is initially synthesized as an Mr = 53,000 precursor that is processed by ...
Quintal R - - 1984
Ventricular fibrillation has been only rarely observed as a complication of cardiac pacing after the advent of demand pacemakers. Automatic AV sequential pacing (DDD) may provide the setting for ventricular fibrillation in patients with junctional rhythms. In this report we present two patients with implanted DDD pacemakers in whom ventricular ...
Madigan N P - - 1984
The dislodgment rate of permanent pacing ventricular and atrial endocardial leads has significantly decreased with the incorporation of tines as a fixation device. In contrast, transvenous manual extraction of chronically implanted endocardial leads is, at times, clinically indicated, particularly when pacemaker system infection is present. The success rate of such ...
Bowman T A - - 1984
Pre-clinical studies of cardiac pacemakers and new electrodes, materials, and designs are for the most part conducted in dogs. Dogs, however, have electrophysiological differences which may preclude accurate translation to clinical trials. The purpose of this study was to develop normal electrophysiological parameters for an animal whose cardiovascular system more ...
Millar R N - - 1984
Atrial trigeminy was seen in a patient with a normally functioning DVI pacemaker (Byrel-5992). Atrial competition resulted from coincidence of sinus and atrial escape rates together with late ventricular sensing. This resulted in atrial output stimuli occurring within the QRS complex. Alternate impulses occurred late enough to conduct to the ...
Schiavone W A - - 1984
A transvenous left ventricular endocardial pacemaker catheter is a potential source of systemic arterial embolization. The case of a woman who presented with left-eye amaurosis fugax is reported. The patient had a history of contralateral carotid atherosclerosis; however, the digital subtraction angiography of the carotid arteries was not sufficiently abnormal ...
van Mechelen R - - 1984
To evaluate factors playing a role in initiation and perpetuation of pacemaker-mediated tachycardias (PMTs), 22 consecutive patients with symptomatic conduction disorders were studied after implantation of an AV universal (DDD) pulse generator (Cordis 233D). Patients were divided into two groups, depending upon the presence or absence of ventriculo-atrial (VA) conduction ...
van Gelder L M - - 1984
A 45-year-old man who had been implanted with a VVI pacemaker for sinus arrest complained of syncope, dizziness and throbbing in the neck. His pacemaker function was normal, but during ventricular pacing, retrograde V-A conduction was observed. This pacer was replaced by a DVI unit which caused periodic abdominal muscular ...
Fisher J D - - 1984
The possibility of adapting multimode dual-chamber pacemakers for programmed and burst stimulation was explored in a group of patients with ventricular tachycardia. The potential usefulness and pitfalls of these pacemakers were exemplified in one patient, presented in detail. The implanted DDD pacemaker was programmed to an all-synchronous mode (DDT), permitting ...
Amikam S - - 1984
A 3-beat episode of ventricular arrhythmia was recorded in a patient with an AV universal (DDD) pacemaker. This arrhythmia mimicked "endless loop" tachycardia (ELT) because it appeared following a ventricular premature contraction (VPC), its rate approached the preset upper-rate limit and the regular P waves disappeared during the episode. However, ...
Mészáros J - - 1984
The electrophysiological effects of bromobenzoyl - methyladamantylamine ( BMA ) were investigated in isolated electrically driven right ventricular papillary muscles of guinea pigs using conventional glass-microelectrode technique. BMA markedly increased the action potential duration, depolarized the membrane, reduced the maximum rate of depolarization (Vmax) and induced pacemaker-like action potentials. In ...
DiCola V C - - 1984
It has long been possible to prevent death from bradycardia by using single-chamber ventricular pacemakers. Important advances in dual-chamber pacemaker technology now make physiological control of cardiac output during pacing almost a reality. These pacemakers have properly timed atrial contraction and rate variability and have significant hemodynamic advantages over ventricular ...
Parsonnet V - - 1984
In April, 1973, a decade-long study was begun on nuclear-powered pacemakers. The first 15 of these were designed by the Numec Corporation under a contract from the United States Atomic Energy Commission. Altogether 151 units powered by the isotope plutonium 238 were implanted in 131 patients; the pacemakers of 4 ...
Quintal R - - 1984
This case report describes myopotential interference with an automatic AV sequential pacemaker (DDD) producing repetitive firing of the ventricular channel up to a rate of 160 and occasional suppression of the ventricular output. A silastic boot which covered the pacemaker did not prevent sensing of electromyopotentials. The problem was partially ...
Gold R D - - 1984
Progress in both the health sciences and engineering sciences has been necessary for the development of the cardiac pacemaker. From the invention of the vacuum tube triode amplifier in 1906 to that of the oscillator just a few years later; from the early electrocardiograph in 1906 and the first stimulation ...
Reddy C P - - 1984
A patient with recurrent sustained ventricular tachycardia that was resistant to both conventional and experimental antiarrhythmic agents was treated with a programmable automatic scanning extrastimulus pacemaker. The antitachycardia pacemaker was implanted only after many episodes of spontaneous and laboratory-induced ventricular tachycardia were reliably and reproducibly terminated with programmed ventricular extrastimuli. ...
Dangman K H - - 1983
The effects of overdrive stimulation were studied on preparations of isolated canine cardiac Purkinje fibers using standard microelectrode techniques. Preparations were made from false tendons, the subendocardial right bundle branch and 24 hour infarct zone Purkinje fibers. Three types of automaticity were recognized: high potential automaticity occurred in fibers with ...
Richards P - - 1983
The anatomical findings in 52 patients undergoing posterior fossa exploration for idiopathic trigeminal neuralgia are described. Anatomical abnormalities in the cerebello-pontine angle were found in 46. The commonest was an arterial loop indenting or distorting the nerve at the root entry zone. In view of this the operative procedure has ...
Sutton R - - 1983
Fifty-three patients have received 'physiological' pacemakers, 37 with atrioventricular (AV) block having atrial synchronous units (VAT or VDD) implanted and the remaining 16 patients with both AV block and sick sinus syndrome having 'universal' (DDD) pacemakers. Effort tolerance was assessed by serial bicycle ergometry and in 16 patients direct comparisons ...
Lerman B B - - 1983
A multiprogrammable automatic antitachycardia pacemaker (Cybertach-60), connected to a tined "J" wire electrode, was positioned in the right atrial appendage in three patients with recurrent supraventricular tachycardia (SVT). Mechanisms of SVT included atrioventricular (AV) nodal reentry (two patients) and reciprocating tachycardia using an accessory pathway (one patient). Indications for implantation ...
Pourhamidi A H - - 1983
It was previously thought that diagnostic or therapeutic ionizing radiation did not have an adverse effect on the function of cardiac pacemakers. Recently, however, some authors have reported damaging effect of the therapeutic radiation on cardiac pulse generators. An analysis of a recently-extracted pacemaker documented the effect of the radiation ...
Luceri R M - - 1983
The field of cardiac pacing has developed exponentially in the past several years. The widespread use of atrioventricular synchronous pacemakers has resulted in the recognition of several types of pacemaker-associated arrhythmias. Certain of these arrhythmias follow asynchronous stimulation of either cardiac chamber; others are the result of the artificial bypass ...
Sebben J E - - 1983
There are two basic types of cardiac pacemakers: (1) Fixed-rate pacemakers stimulate the heart at a regular rate independent of the intrinsic heart rate. (2) Demand pacemakers sense the heart's spontaneous rhythm. They are more commonly used because they are noncompetitive with the heart. There are two varieties of demand ...
Broadbent J C - - 1983
Reentrant tachycardia occurred after implantation of an atrial synchronous ventricular-inhibited pacemaker in a patient with bradycardia caused by second-degree (Mobitz II) atrioventricular block. Despite the presence of antegrade atrioventricular block, intact ventriculoatrial conduction was present at a cycle length that exceeded the atrial refractory period of the pacemaker. Consequently, a ...
Littleford P O - - 1983
The DDD pacemaker allows sensing and pacing in both chambers and can, therefore, maintain atrioventricular synchrony. However, this pacemaker creates an additional anterograde conduction system between the atrium and ventricle and, in the presence of ventriculoatrial (VA) conduction, the possibility of pacemaker-mediated tachycardia exists. A simple bedside technique that does ...
De Albuja C M - - 1983
In the egg-brooding frog Gastrotheca riobambae (Fowler), oocyte maturation is comparable to the situation of other frog species. In isolated follicles, progesterone induces only germinal vesicle breakdown (GVBD), while human chorionic gonadotropin (hCG) induces GVBD and ovulation. In addition, defolliculated oocytes respond with GVBD to the treatment with progesterone, while ...
Aris A - - 1983
A newly designed temporary pacemaker wire has been tested in 20 patients who underwent open-heart operations. This new device has a small tip that stays securely buried in the myocardium, thus greatly reducing the risk of accidental dislodgment. In addition, the increase in thresholds during the postoperative period is slighter ...
Shaw D B - - 1983
We describe our initial experience with a pacemaker which performs the dual function of registering episodes of cardiac arrest and pacing the heart when necessary. The apparatus has a prolonged escape interval (2.30-2.65 seconds) and is capable of counting up to 128 "events." Twenty-five patients complaining of infrequent episodes of ...
Hughes H C - - 1983
A new segmented polyether polyurethane atrial pacemaker lead has been developed and tested acutely and chronically in dogs. This lead was constructed so that its tip could quickly and accurately be positioned in close proximity to the S-A node and provide long-term stability without the use of active fixation devices ...
Kratz J M - - 1983
Temporary external pacemakers have been reported to fail under hyperbaric conditions. In this study we investigated cardiac pacing under hyperbaric conditions. Permanent hermetically sealed pacemakers were found to function well under hyperbaric conditions, while several models of temporary external pacemakers failed. The electrical characteristics of pacing leads did not change ...
Kerr C R - - 1983
A 68-year-old man with sick sinus syndrome and a history of intermittent atrial fibrillation was treated by implantation of a DDD pacemaker. He subsequently developed recurrent episodes of shortness of breath and tachycardia. Investigation revealed two different arrhythmias, both induced by the pacemaker: (1) a tachycardia in which the dual-chamber ...
Rubin J W - - 1983
Twenty adults underwent implantation of an automatic (DDD) pacemaker (Medtronic model 7000, Versatrax I) for treatment of symptomatic bradyarrhythmias. Only 9 patients had optimal DDD mode pacing during 78 paced months. In 3 patients, the DDD mode was changed to atrioventricular (AV) sequential (DVI) early because of risk imposed by ...
Belott P H - - 1983
Two patients with documented pacemaker syndrome were referred for AV sequential pacing and were found to have inaccessible venous systems on the side of their original transvenous pacemaker placement. The contralateral subclavian vein was subsequently catheterized with an atrial electrode using the sheath-set technique. Then the proximal aspect of the ...
Rosengarten M D - - 1983
Artificial pacing of the heart has evolved rapidly over the last 20 years; the physician can now implant "physiologic" pacemakers that preserve the natural order of atrial and ventricular systole. The commonly used pacemakers that pace only the ventricle can induce dizziness, fatigue and syncope and increase congestive heart failure. ...
Medina-Ravell V - - 1983
Multiprogrammable dual-demand AV sequential (DVI, MN) pacemakers were implanted in twenty-three patients (in one of them a DVI, MN unit was used as a VVI, MN with the aid of an atrial plug) with supraventricular tachycardias after electrophysiological studies revealed a great variety of AV reentry circuits. The latter included ...
Ripart A - - 1983
Clinical evaluation performed on an external prototype of a programmable VDD pacemaker showed a high risk of induction of pacemaker-mediated tachycardia. In these tests tachycardia was observed following magnet removal, premature atrial and ventricular complexes, myopotential oversensing, detection of electrical interference and other events. The high risk and poor predictability ...
Elmqvist H - - 1983
Pacemaker mediated re-entry tachyarrhythmias and their causes are discussed. Several methods to prevent these arrhythmias are presented. It is shown that the most efficient method incorporates a long refractory period of the atrial detection after ventricular depolarization. The benefits of a short A-V delay after atrial sensing are discussed.
Calfee R V - - 1983
The proliferation of dual-chamber pacemakers has resulted in several different modalities of DVI pacing. A distinction is made between "committed" and "non-committed" modes, and the differences are presented. In addition, a new hybrid mode has been developed which has been termed "semi-committed" and is currently being introduced. The semi-committed mode ...
Goldberg J M - - 1983
The effects of supramaximal stimulation of the right and left cervical vagi on heart rate, pacemaker localization, and atrioventricular (AV) conduction were investigated in 15 anesthetized open-chest chickens before and after atropine sulfate. Epicardial bipolar electrograms were recorded from selected atrial sites and right ventricle. A back lead electrocardiogram was ...
Berkovits B V - - 1983
Interchangeability between pacing modes will be the key feature in the pacemaker of the 1980s. The usefulness of the various modes will be enhanced by the array of pacing parameter options made available within each mode. Noninvasive adjustments of rates, AV intervals, signal detection sensitivities, and both atrial and ventricular ...
Kosowsky B D - - 1983
Transient asystole is often noted during the course of permanent pacemaker implantation in patients with complete heart block. Since subcutaneous lidocaine is frequently used as the local anesthetic agent for permanent pacemaker implantation, the effect of this drug on ventricular escape intervals was studied. Ventricular escape intervals after transient cessation ...
Meester G T - - 1983
Given the not infrequent need for intracardiac pacemaking during intensive cardiac care, a new type of cardiac pacemaker has been designed and tested [1]. With this pacemaker the heart can be stimulated through the fluid column of any conventional catheter, provided it is filled with a 0.9% NaCl solution. This ...
Hörnchen H - - 1983
Cardiorespirography is a well-known method of continuous monitoring in neonatal intensive care. Apneic attacks, bradycardia and tachycardia are registered. In our experience we connected a cardiorespirography recorder to a microprocessor system. The processor consisted of a hardware part including a program (software) and a printer which provided printouts of alarm ...
Hearne S F - - 1982
Air entrapment within the pulse generator pocket may produce pacemaker system malfunction if the anodal contract plate becomes insulated by the accumulation of air. Unipolar pulse generators are predisposed to this complication. We describe a pacemaker-dependent patient who, early after implantation, experienced pacemaker system failure as a complication of subclavian ...
Alpert M A - - 1982
To explore the natural history of symptomatic sinus node dysfunction after permanent pacemaker implantation, we followed up 71 patients (27 with sinus arrest, 27 with unexplained sinus bradycardia, 14 with the bradycardia/tachycardia syndrome, and three with sinoatrial block) for four to 14 years after placement of a permanent ventricular pacemaker. ...
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