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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. ...
O'Connor J V - - 1982
The use of cardiac pacemaker technology has greatly decreased the morbidity and mortality caused by certain cardiac arrhythmias. Its use, however, has not been without complications, including broken or dislodged pacemaker leads, failure of the pacemaker to sense the QRS complex, and cardiac arrhythmias. This paper presents a straightforward and ...
Brownlee R R - - 1982
A new symbolic language is presented that can be used to diagram pacemaker/heart interactions. The language symbolically indicates "normally" conducted and ectopic events; pacemaker stimuli; pacemaker capture of the chamber; triggered pacemaker stimuli by "normal" or ectopic events; as well as such anomalous pacemaker/heart interactions as failure to sense; "crosstalk" ...
Berman N D - - 1982
A patient with drug-resistant supraventricular tachycardia was well controlled for 8 years with a patient-activated rapid atrial pacemaker until she developed symptomatic bradycardic episodes. A multiprogrammable ventricular pacemaker was implanted. Assessment of the interactions between the two pacemakers demonstrated inhibition of VVI pacing by the atrial stimulator initially. Two months ...
Botvinick E H - - 1982
The ability of scintigraphic phase image analysis to characterize patterns of abnormal ventricular activation was investigated. The pattern of phase distribution and sequential phase changes over both right and left ventricular regions of interest were evaluated in 16 patients with normal electrical activation and wall motion and compared with those ...
Furman S - - 1982
Implantation of an AV universal [DDD] pacemaker, stimulating and sensing both atrium and ventricle caused a pacemaker mediated tachycardia, begun by a P wave occurring after a premature ventricular contraction, and sustained by P waves caused by retrograde AV conduction. The tachycardia was terminated by application of a magnet to ...
Scheibelhofer W - - 1982
The induction of ventricular tachycardia or ventricular fibrillation by competitive pacing, especially in the setting of acute myocardial ischemia, is well known. A case of ventricular tachycardia induced by a multiprogrammable unipolar cathodal ventricular pacemaker is reported. The arrhythmia was caused by reprogramming, which necessitates a short switch to fixed ...
Lüderitz B - - 1982
Newer electrophysiological studies have improved our understanding of the pathogenesis of cardiac arrhythmias. Bradycardias originate either from a dysfunction of impulse formation in the sinoatrial node or from a disturbed conduction of the impulse. Different pathogenetic mechanisms are discussed as causes of tachyarrhythmias: circus movement (re-entry) is primarily due to ...
Tommaso C - - 1982
Asynchronous cardiac pacing may induce ventricular tachycardia and fibrillation, particularly in patients with ischemic heart disease and possibly other types of myocardial abnormalities. All patients with implanted asynchronous pacemakers, and those whose demand pacemakers operate in asynchronous mode for any reason, are to be considered at risk from this complication. ...
Freedman R A - - 1982
Atrial synchronous pacemakers have been known to cause a variety of cardiac arrhythmias. Of particular concern are those arrhythmias involving a pacemaker stimulus occurring on a T wave, because these may lead to ventricular tachycardia. The Medtronic 2409 ASVIP pacemaker is an atrial synchronous pacemaker with several features designed to ...
dos Santos L A - - 1982
Fifty-seven Black patients received permanent cardiac pacemakers at Baragwanath Hospital, Johannesburg, over a 7 1/2-year period. Most patients had established complete heart block (77%), while very few had intermittent conduction disorders or sinus node dysfunction. In most patients the cause of the conduction disease was unknown but was probably primary ...
Peake J B - - 1982
Two patients developed left pneumothorax after nerve conduction studies were done as part of their evaluation for left thoracic outlet syndrome (TOS). Chest x-rays indicated a 20% and 10% left pneumothorax, respectively. Stimulation was accomplished at Erb point with a 1 1/2-inch needle electrode after unsuccessful attempts at percutaneous stimulation. ...
Gupta S C - - 1982
Extracardiac sounds secondary to cardiac pacing are well known, but the murmurs originating in the heart after pacemaker insertion are rare. A patient who developed musical systolic murmur following temporary transvenous endocardial pacemaker insertion is described. It is concluded that the murmur was produced by vibrations caused by the pacing ...
Tolentino A O - - 1982
A 68-year-old white male underwent permanent pacemaker implantation with an atrial synchronous ventricular inhibited pulse generator (Medtronic model 2409) because of syncope and abnormal H-V interval of 70 ms. Paroxysmal bouts of pacemaker associated tachycardia were subsequently recorded on several occasions, initiated and terminated by spontaneous ventricular premature beats. The ...
Morin J E - - 1982
The type, frequency and duration of use of temporary pacemaker wires were recorded in 100 patients who underwent in 100 patients who underwent open-heart surgery. Sixty-five patients had wires implanted: 29 were atrioventricular 35 ventricular and 1 atrial. Pacing was required in 24 instances for nodal rhythm, sinus bradycardia, sinus ...
Castellanos A - - 1982
Three simultaneous leads (I, II and VI) were recorded in a patient with a normally functioning bipolar AV sequential (DVI) pacemaker. Superimposition of the ineffectual atrial spikes upon the early part of the QRS complexes resulted in pseudo-pseudofusion beats, clearly identified in lead II. However, the small spikes were hardly ...
Spurrell R A - - 1982
Thirteen patients suffering from reentrant supraventricular tachycardia have undergone implantation of a scanning extrastimulus pacemaker. This pacemaker is fully implanted and automatic, and it requires no external control device to activate or control it. The pacemaker is activated when tachycardia occurs. After four cycles an extrastimulus is induced with a ...
Austin J L - - 1982
The medical records of 100 patients who received 113 temporary transvenous pacemakers were reviewed to determine the incidence of complications and malfunction. Malfunction, defined as failure to capture or sense, or both, occurred in 42 (37 percent) of 113 temporary pacemakers. The initial malfunction occurred within 24 hours in 21 ...
Hess D S - - 1982
During a 36-month period, 171 permanent pacemaker procedures were performed in the cardiac catheterization laboratory by invasive cardiologists. This included 111 initial pacemaker system implants, via the percutaneous subclavian vein approach, 45 pulse generator changes, and 15 miscellaneous procedures. In no case did subclavian vein puncture result in pneumothorax, hemothorax, ...
Fisher J D - - 1982
Implanted pacemakers can provide a viable alternative to pharmacologic therapy or surgical management of patients with recurrent ventricular tachycardia. An increasing variety of pacemaker techniques are proving useful for preventing, controlling the effective rate of or terminating ventricular tachycardia. To assess the role of permanent pacing in the treatment of ...
Randall W C - - 1981
Definitive subsidiary atrial pacemakers (SAPs) exist within the crista terminalis and in the atrial free wall tissue at the junction of the inferior vena cava and the inferior right atrium. These pacemakers are capable of maintaining cardiac rhythm at a rate intermediate between that of the sinoatrial (SA) nodal and ...
Barold S S - - 1981
This paper describes our approach to the interpretation of electrocardiograms produced by a new unipolar multiprogrammable "committed" DVI pulse generator (Intermedics) during normal function. The arrhythmias engendered by this new DVI pacemaker may be better understood by conceptualizing the recycling mechanism in terms of a simple atrial pulse generator with ...
Goicolea De Oro A - - 1981
An unusual case of pacemaker failure induced by atrial activity is presented. The pacemaker stimulus was ineffective for ventricular capture not only with low energy output (decreased pulse duration) of the generator, but also with pulse width two to three times the stimulation threshold. The two possible mechanisms of this ...
Giles W - - 1981
Application of the voltage clamp technique to cardiac primary pacemaker tissue has yielded sufficiently detailed information that a qualitative model of the pacemaker response can now be formulated. One important difference between the generation of spontaneous activity in sinus tissue, and in the Purkinje fiber, appears to be the involvement ...
Van Gelder L M - - 1981
An implanted ventricular demand pulse generator started firing at a rate of 1200 ppm during routine pacemaker follow-up utilizing the Vitatron VA 1000 pacemaker analyzer. This resulted in complete loss of capture; fortunately the patient had an intrinsic heart rate of 50 bpm and remained asymptomatic. Emergency replacement of the ...
Ishikawa K - - 1981
In this study, an attempt was made to determine how the P-terminal force (P-tf) was influenced by an upward shift of the V1 electrode in 508 normal subjects, 101 patients with hypertension, 22 with chronic obstructive lung disease (COLD), and 55 with old myocardial infarction. An abnormal V1 P-tf (less ...
Hicken P - - 1981
The left upper quadrant of the abdomen is frequently a "blind" area for ultrasonographic scanning due to the preponderance of gas in the stomach and splenic flexure of the colon, which obscures the deeper structures. Longitudinal scans, particularly when done vertically, are generally of no use in this region. A ...
Furuse A - - 1981
The intrinsic cycle length of the ventricular parasystolic pacemaker may be modulated by electrotonic influence of intervening ventricular depolarizations. In order to quantify the magnitude of modulation in relation to the timing of the intervening depolarization, a curve of influence was constructed in a patient with ventricular parasystole. The current ...
Lewis M E - - 1981
We report a case of hypotension and decreased cardiac output resulting from artificial ventricular pacemaker rhythm. Hemodynamic deterioration was associated with loss of normal time relationships between atrial and ventricular contraction and paradoxical fall in systemic vascular resistance despite a low output state. The therapeutic implications of this unusual response ...
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