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Results 701 - 750 of 995
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Inoue D - - 1987
Two cases of malfunctioning APC (American Pacemaker Company) Devices pacemakers are reported. Two patients with sick sinus syndrome were temporarily paced using APC Devices pacemaker models EC 4542 and EV 4543 respectively, which showed transient increase (53% and 83% of the preset rate, respectively) in pacing rate. The sudden increase ...
Gilchrist I C - - 1987
The risk of life-threatening ventricular arrhythmias complicating coronary angiography is reportedly increased in patients in whom temporary righ ventricular pacemakers are used. Placement of the temporary pacing electrode in the right atrium or vena cava during angiography theoretically removes from the vulnerable ventricle a source of mechanically or electrically induced ...
Janosik D L - - 1987
The value of ambulatory electrocardiography (AECG) in detecting pacemaker dysfunction before hospital discharge was assessed in 100 patients a mean of 1.2 days after pacemaker implantation. The incidence of permanent pacemaker dysfunction detected by AECG in the early postimplantation period, the frequency that pacemaker dysfunction detected by AECG was not ...
Barold S S - - 1987
Fifty-seven patients with implanted DDD pulse generators (23 Intermedics Cosmos and 34 Medtronic Symbios) were studied to characterize the behavior of the so-called ventricular safety pace period or nonphysiologic AV delay (ventricular triggering period) in a variety of circumstances. The pulse generators were programmed to various combinations of upper rate, ...
Schang J C - - 1987
The effects of vasopressin on colonic motility were investigated in 6 healthy subjects and 10 patients with chronic idiopathic constipation. Recordings of the colonic myoelectric spiking activity were performed by means of 50-cm long silastic tube, equipped with four bipolar ring electrodes fixed at 10-cm intervals, which was introduced by ...
Malik M - - 1987
A computer simulation model of cardiac rhythm and heart-pacemaker interactions has been used to examine the response of short AV delay DDD pacing to an atrial premature depolarization in patients with a potential junctional reentry circuit. Special attention was given to the possibility of using the pacemaker to prevent atrioventricular ...
Jadvar H - - 1987
There are many clinical situations that present the need for special purpose electrocardiography using standard equipment. These include monitoring cardiac activity from temporary myocardial leads implanted following cardiac surgery, detecting signals from intracardiac catheter leads, and noninvasive atrial recording from the esophagus. It is often difficult to connect nonstandard leads ...
Toivonen L K - - 1987
Disabling presyncopal attacks were provoked in a patient with a sinus nodal disorder and cardiac pacemaker by treatment with antianginal vasodilators. At cardiac catheterization a severe fall in aortic pressure was documented during ventricular pacing, when desynchronized atrial contractions coincided with ventricular systoles. After withdrawal of the medication, no obvious ...
Haxton M J - - 1987
Abnormalities of in-vitro sperm-mucus penetration, ovarian hormone deficiency, specifically poor progesterone surge, and luteal cyst formation were assessed prospectively in 95 couples with fully investigated primary infertility of greater than or equal to 3 years duration. Abnormal sperm-mucus penetration was found in 22, half of whom could have been identified ...
Quintal R E - - 1987
We describe pacemaker pauses and pseudohysteresis resulting from sensing of retrograde P waves in a patient with an implanted AV sequential universal pacemaker. Although retrograde P waves are usually followed by a ventricular spike and therefore create the possibility for "endless loop tachycardia," in our patient some retrograde P waves ...
Sheron N - - 1987
The loss of atrial contraction can seriously impair cardiac output when complete heart block follows myocardial infarction. We describe two cases in which temporary sequential atrioventricular pacing was lifesaving. The pacemaker used was a previously explanted internal pacemaker. By avoiding the need for an expensive dedicated temporary pacemaker this technique ...
Kuhn H J - - 1987
The development of the heart of Tupaia belangeri from the first endothelial-lined lumina to the cardiac loop is described in 20 embryos with 2 to 14 somites, from ontogenetic days 11 and 12. Bilateral endocardial tubes transporting blood are found in the 8-somite embryo; in the middle cardiac plate, angioblasts ...
Hoeppner J B - - 1987
Stories were elicited from 29 epileptic patients with generalized, simple partial, and complex partial seizures with bilateral, right, or left foci, and from 32 persons in two control groups. Four older epileptic patients with long histories of left complex partial seizures were verbose. Their stories involved trivial and subjective details, ...
Skepper J N - - 1986
The structure of nexuses in the atrioventricular node of the golden hamster was studied with the transmission electron microscope, using thin sections and freeze-fracture replicas, and was compared with that of nexuses in the working myocardium of the right ventricular wall. Whereas ventricular myocardium contained macular nexuses only, nodal tissue ...
Cubicciotti D D DD - - 1986
The New World primates Callicebus moloch and Saimiri sciureus differ markedly in life modes. Physiological responsiveness (heart rate, cortisol) of these related taxa was compared in two situations that differed in the presumed degree of stress imposed, exposure to a novel environment and physical restraint. In both situations, Saimiri exhibited ...
Malhotra R - - 1986
Growth in the thoracic region and its adaptation to higher altitude was investigated in boys between 5 to 18 years of Rajput origin at two altitudes, i. e. Rampur Bushahr (800 m above sea level) and Kinnaur (3,000 m above sea level). Both places are located in Himachal Pradesh. The ...
Markewitz A - - 1986
Sinus node disease (SND) has caused many controversies about the appropriate stimulation mode. We compared the advantages and disadvantages of VVI, AAI, DDD, and DDI mode. In an additional study, left ventricular function at rest (R) and during exercise (E) was investigated in dual chamber and ventricular stimulation mode with ...
Zimmern S H - - 1986
Myopotential signals were recorded from atrial and ventricular leads during isometric exercise in 25 patients who had chronically implanted dual chamber pacemakers using the electrogram telemetry capability of the pacemakers. Average electrogram amplitude on the atrial channel was 0.92 mV (range 0.3 to 1.9) and on the ventricular channel was ...
Brownlee W C - - 1986
This report describes a six-year experience with atrial leads consisting of 329 unipolar and 12 bipolar leads implanted in 302 patients. A variety of lead types were used: passive fixation with preformed J (including tines or fins in a solid electrode); porous tip electrodes with small tines, most of which ...
Burggren W - - 1986
Dose-response curves for the action of acetylcholine (ACh) and its antagonist, atropine, upon heart rate in situ were made for three larval stages and adults of the bullfrog, Rana catesbeiana. The absolute magnitude of heart rate inhibition at any ACh concentration progressively increased throughout larval development. Unexpectedly, metamorphosis to the ...
Manz M - - 1986
Antitachycardia pacing for ventricular tachycardia (VT) is associated with the possibility of fibrillating the heart; on the other hand, the frequency of VT and patient discomfort can limit treatment with the automatic implantable cardioverter/defibrillator (AICD). To contribute to the further development of a universal pacemaker, we evaluated the combined use ...
Fröhlig G - - 1986
Three patients are reported whose DDD pacemakers reverted to the asynchronous mode in the absence of skeletal muscle or electromagnetic (EMI) interference. In all three cases, the basic cardiac rhythm was atrial fibrillation with fast ventricular response due to intrinsic AV conduction. Noise reversion was triggered by the patients' own ...
Wang F S - - 1986
Prolonged electrocardiographic (Holter) recording was performed to analyze terminal electrical events in 23 hospitalized adults who died without apparent cardiac disease. Most patients showed a gradual slowing of heart rate with shifting of cardiac pacemaker downward from the sinus node or atria to the atrioventricular junction and ventricles, resulting in ...
Oreto G - - 1986
Modulation of ventricular parasystole by sinus beats has been shown both in vitro and in vivo to result in a classic biphasic phase-response curve. The first clinical presentation of 3 cases of supernormal modulation of ventricular parasystole resulting in a triphasic phase response curve is reported. Supernormal modulation reflects an ...
Higgins J R - - 1986
An automatic burst pacemaker (Cybertach-60) was used to treat drug-resistant recurrent ventricular tachycardia in a patient with mitral valve prolapse. The arrhythmia was associated with multiple syncopal episodes and aborted sudden death. During a 23 month follow-up period the patient has remained asymptomatic and more than 2,000 episodes of ventricular ...
van Mechelen R - - 1986
ECG tracings of three patients in whom AV universal (DDD) pacemakers were implanted intermittently demonstrated dropped P waves. In one patient, true atrial undersensing was present; in the others, sensing of the atrial electrode was appropriate, but sensing of sinus P waves was intermittently blocked by normal pacemaker operation. In ...
Robbens E J - - 1986
A patient who suffered from sinus node dysfunction and automatic atrial tachycardias underwent pacemaker implantation during which time a unilateral left superior vena cava was found. Despite the known difficulties in using this venous route, it was possible to place a transvenous endocardial screw-in lead in a stable position in ...
Cripps T - - 1986
The uptake of cardiac catheterisation and operation and of permanent pacemaker implantation in a district hospital in Surrey from 1979 to 1984 was studied prospectively. The 1982-84 figures for coronary artery operation indicated that 362 procedures/million population/annum were needed in the district. If patients with greater than or equal to ...
Greenspon A J - - 1986
A 48-year-old man with previous aortic valve surgery and aortic root repair had a DDD pacemaker inserted (using transvenous leads) for the treatment of complete heart block. An atrial J active fixation electrode was used. Four weeks following implantation the patient returned with an unusual electrocardiographic rhythm demonstrating two separate ...
Masini G - - 1986
The aim of this study was to investigate whether premature atrial stimulation is able to induce a shifting of the sinus node pacemaker. For this purpose we compared, in 18 patients, the curve of sinus node function obtained with Strauss' method with that resulting from the scanning, with premature atrial ...
Szekeres L - - 1986
In the present experiments the dominant role in the genesis of arrhythmias of stimulation of beta adrenoceptors over that of alpha adrenoceptors has been demonstrated by: (i) infusion of catecholamines in the isolated right ventricular Purkinje fiber preparation of rabbits; and (ii) by subepicardial microinfusion of these substances to anesthetized ...
Reisen W K - - 1986
Exposure to simulated "mid-winter" conditions (16 degrees C, 10L:14D) inhibited the expression of autogeny among the female progeny of field-collected Culex tarsalis females. The same F1 progeny expressed 43% autogeny when reared in an insectary under simulated "summer" conditions (25 degrees C, 16L:8D). Diapausing F1 progeny did not express autogeny ...
Sukhum P - - 1986
Methods and devices for permanent cardiac pacing remained relatively stable for over two decades with use of the single-chamber ventricular demand (VVI) pacemaker. However, changes have occurred in the 1980s and are expected to continue with the availability of more advanced technology and with increasing knowledge about cardiac pacing. The ...
Lamas G A - - 1986
Both electrocautery and internal defibrillation are routinely used in cardiac operations. The cases of 5 patients are presented in whom backup-mode reversion or injury of permanently implanted pulse generators occurred during a cardiac procedure. The theoretical explanations for backup-mode reversion and generator or tissue injury are discussed, and recommendations are ...
Pimenta J - - 1986
A 44-year-old female had Chagas' disease with right bundle branch block, right axis deviation, and ventricular ectopic beats. An invasive evaluation showed a prolonged HV interval of 100 ms. A Medtronic Versatrax 7000 was implanted, after which a pacemaker-mediated tachycardia was observed. The esophageal lead ruled out the possibility of ...
Kovács K L - - 1986
The effects of surfactants, lipids and amphiphilic viologen mediators on H2 production from dithionite as well as on Ru(bpy) sensitized H2 photoproduction by hydrogenase from Thiocapsa roseopersicina was studied. Three systems which differed as to the nature of the hydrophobic matrix around the hydrogenase were tested. An enhanced hydrogenase activity ...
Fromell G J - - 1986
The Wenckebach phenomenon, or type I AV block, refers to a progressive lengthening of impulse conduction time, followed by a nonconducted impulse, or dropped beat. It can occur in a variety of pathologic settings, especially inferior myocardial infarction. Although a temporary pacemaker may be required, full spontaneous recovery is the ...
McCabe J B - - 1986
A 68-year-old man with sick sinus syndrome was treated by implantation of a DDD pacemaker. He subsequently developed a rapid heart rate and was found to have a pacemaker-mediated tachycardia due to tracking of atrial fibrillation by the pacemaker. The tachycardia was abolished by reprogramming the pacemaker, and the patient ...
Beaver B B - - 1986
A unique mechanism of "cross-talk" has recently been described in the Gemini 415A DDD pacemaker in which cross-inhibition of the ventricular output stimulus may occur in the early Gemini 415A models which were manufactured with dual anodal rings interconnected by a wire. The Gemini 415A units with dual anodal rings ...
Barold S S - - 1985
Signals responsible for pacemaker oversensing may arise from the pacing system itself, P or T wave, concealed ventricular extrasystoles, skeletal muscle potentials, and distant electromagnetic fields. Oversensing is the most common cause of pacemaker pauses and a common clinical problem during follow-up of patients with implanted pulse generators. This article ...
Ausubel K - - 1985
The pacemaker syndrome is an iatrogenic disorder that can result from hemodynamic sequelae of ventricular pacing. Symptoms range from fatigability to syncope and occur during the time the ventricles are being stimulated by the pulse generator. Postulated mechanisms include loss of atrioventricular synchrony, vasodepressor reflexes, and retrograde atrial activation. Prevention ...
Gilchrist J M - - 1985
We studied a young man with presumably idiopathic seizures that were refractory to phenytoin therapy. Sick sinus syndrome was found after an episode of unconsciousness, but seizures continued despite the insertion of a demand ventricular pacemaker. Evaluation revealed a left temporal seizure focus, and combined EEG and ECG monitoring during ...
Rubens A B - - 1985
We studied performance on tests of visual neglect and left lateral gaze after caloric stimulation in 18 patients with left-sided visual neglect after strokes. Except for one patient with absent vestibulo-ocular responses, all improved during caloric stimulation on the left by cold (LC) or on the right by warm water ...
Janosik D - - 1985
Torsades de pointes, a distinctive type of polymorphous ventricular tachycardia, may be induced by critically timed ventricular stimulation during electrophysiologic studies or, rarely, in patients with temporary or permanent ventricular pacemakers. The following case illustrates how, when temporary ventricular pacing is instituted to maintain heart rate in a patient with ...
Surawicz B - - 1985
Ventricular fibrillation is the most common mechanism of sudden unexpected cardiac death in persons with asymptomatic or symptomatic coronary artery disease. The electrophysiologic mechanisms reviewed in this article include: automaticity of pacemaker fibers, transformation of nonpacemaker into pacemaker fibers, "injury" currents and reentry. Some of the conditions facilitating ventricular fibrillation ...
Lamas G A - - 1985
Pacemaker-mediated tachycardias (PMT) have received much recent attention. We describe the course and treatment of a 60-year-old man with an AV universal (DDD) pacemaker who developed a pacemaker-mediated tachycardia. The tachycardia was initiated by the coincidence of an unsensed P-wave, a QRS that was also not sensed due to the ...
Jeans S P - - 1985
Measurements of radiation distributions in the vicinity of the couch were undertaken for a number of projections commonly employed during cardiac radiological studies. Three types of investigations were considered; cardiac catheterisations, pacemaker implants and percutaneous transluminal coronary angioplasties. The radiation dose to staff involved in these procedures was estimated. For ...
Brandt J - - 1985
The interpretation of the ECG of a dual chamber pacemaker necessitates the identification of atrial activity. This is a prerequisite for the evaluation of pacemaker function and for the correct adjustment of programmable pulse generators. The assessment of atrial capture in standard 12-lead ECGs is, however, sometimes rather difficult. Esophageal ...
Dangman K H - - 1985
We studied the effects of single premature stimuli on automatic and triggered rhythms occurring in preparations of isolated canine Purkinje fibers. Preparations were made from false tendons, the subendocardial right bundle branch, and infarct zone Purkinje fibers 24 hr after occlusion of the left anterior descending coronary artery, and were ...
Olson C M - - 1985
Cardiac pacing has been used successfully in patients with asystole or bradycardia compromising hemodynamics when it was applied soon after the onset of the event. An external cardiac pacemaker was used as part of initial resuscitative efforts for patients in primary, out-of-hospital, cardiac arrest who arrived in the emergency department ...
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