Inverted Pacemaker Mediated Tachycardia Induced During Noninvasive Electrophysiology Testing

This report describes a case in which an implanted pacemaker programmed to perform noninvasive electrophysiology testing resulted in an unusual form of pacemaker mediated tachycardia. The method of chest wall stimulation was used by programming a unipolar, triggered pacing mode with a short refractory period. In the AAT mode, far-field R wave sensing occurred beyond the physiological atrial refractory period. The triggered atrial response resulted in a single chamber, pacemaker mediated tachycardia.     

Non-invasive Analysis of Simulated Pacemaker Failure Available in Multiprogrammable Pulse Generators

Non-invasive analysis of muscle fascicuhtion using selected sensitivity settings is described This case report demonstrates trouble-shooting methods afforded by the multi-parameter programmable pulse generator while avoiding invasive generator and lead analysis Multiple pacing modes and sensitivities allow simulation of apparent generator malfunctioning as well as variable programming modes best suited to pacing needs     

A New Algorithm for Minimizing Pacemaker Polarization Artifact: Universally Applicable in Permanent Pacing Systems

Polarization artifacts that result from pacing may interfere with analysis of paced evoked responses during, e.g., automatic threshold tracking. We have developed a method for reduction of such artifacts that relies on the introduction of pacing stimuli during the refractory period of unipolar or bipolar paced captured beats after previous identification of a refractory period "template" or baseline. The refractory pacing stimuli cannot capture the heart, and thus any deviation from the template is due to polarization artifact alone. The artifact amplitude is measured and the precharge duration of the triphasic stimulus waveform is changed each time until artifact is minimized, as detected by repeated reversals in the polarily of the polarization artifact. In a series of 11 patients with unipolar and bipolar permanent pacing leads, mean initial artifact before balancing was 1.44 ± 0.84 mV, which was reduced to 0.44 ± 0.30 mV after balancing (P = 0.001). Initial precharge duration was 3.2 msec by design; mean final precharge duration was 3.30 ± 0,34 msec. This algorithm is universally applicable in permanent pacing systems, as it is valid in unipolar and bipolar pacing and it does not require an intrinsic cardiac rhythm.     

Noninvasive Serial Electrophysiological Testing Using an Implanted Pacemaker for Management of Recurrent Ventricular Tachycardia

An implanted multiprogrammable pacemaker capable of performing both premature and burst stimulation can be teamed with a special external programmer for noninvasive electrophysiological testing. Such studies, combined with indications from provocative pharmacologic tests, allowed us to formulate effective antiarrhythmic therapies for three patients suffering from post-infarction, recurrent sustained ventricular tachycardia.     

Suicide Attempt by Pacemaker System Abuse: A Case Report with Comments on the Psychological Adaptation of Pacemaker Patients

Thirty patients selected at random from a pacemaker clinic were interviewed to gain an understanding of how psychological symptoms in these patients related to their cardiac condition. In 20% veiled depression or even a wish to die was elicited. Joking, fantasies, and denial were common psychological mechanisms used to adapt to their illness and the pacemaker itself. A dramatic example of attempted suicide in which the patient tried to cut the subcutaneously implanted pacemaker leads is presented and illustrated.     

Permanent Pacemaker Implantation in the Cardiac Catheterization Laboratory Versus the Operating Room: An Analysis of Hospital Charges and Complications

Permanent pacemakers may be implanted in operating rooms, special procedure laboratories, or cardiac catheterization laboratories. Previous investigators have shown no difference in efficacy or complications in the operating room versus the cardiac catheterization laboratory. We retrospectively analyzed the hospital bills of 30 patients undergoing permanent pacemaker implantation at our institution. Group I was 15 consecutive patients implanted in the operating room and group II was 15 consecutive patients implanted in the cardiac catheterization laboratory, all by the same operators. Hospital charges that were specific to the site of implantation were analyzed. Physician charges for implantation, anesthesiologist, and radiologist charges were not analyzed. There were no in-hospital complications in either group. The mean charges for group I were $1,856.00 and group II were $1,075.00 (P < 0.001). We conclude that implantation of permanent pacemakers in the cardiac catheterization laboratory is associated with significantly lower hospital charges compared to implantation in the operating room and has an equally low complication rate.     

Extraction of Chronically Infected Transvenous Pacemaker Leads: Report of an Unusual Problem

This is a report of a patient with an impacted, chronically infected transvenous pacemaker lead whose management was complicated by the presence of a functioning contralateral transvenous pacemaker. Treatment included sustained traction on the infected lead, a left subcostal thoracofomy for placement of new sutureless epicardial leads, and retrograde right iliac vein cannula-tion for final snare removal of the mobilized lead. The patient is currently free of infection, and has normal pacemaker function.     

MINIMAC: A Totally Numeric 15 Channel Implanted Stimulator

After CHORIMAC-8 and CHORIMAC-12 a new multichannel cochlear implant is presented, characterized by its totally numeric sound signal processing. Owing to FFT the whole speech information is cut into 15 channels, then sequentially transmitted to an implanted receptor and electrode bearer. This digital processing provides the new system with several advantages: 1. miniaturization of outside emitter end implanted receiver; 2. compatibility of this new emitter with the 12 channel receivers implanted in the last 10 years; 3. increasing the number of stimulating electrodes from 12 to 15; 4. simple emitter programming with an IBM-PC; 5. option to postoperatively program the number (1 to 15) and (he value (80 to 3,800 Hz) of the peak filters, and the amplification (6, 10, 18 dB) of each electrode. The next implanted device will have: a. constant current; b. programming of a particular current value for each electrode; and c. stimulation of the cochlear nerve through an extra cochlear electrode bearer, allowing deep implantation without deafness.     

Assistant Programming Software: A New Tool for an Improved Programming of Pacemakers

LASCAULT, G., ET AL.: Assistant Programming Software: A New Tool for an Improved Programming of Pacemakers. Programming the new DDD pacemakers is becoming increasingly difficult. One must take into, account the pacemaker's complexity, the fact that some parameters are linked to others, and the clinical profile of the patient. This difficult problem will lead to the design of software to assist programming, which will help the implanting physicians in choosing adequate programmed settings adapted to the functioning of the device and to the physiology and pathology of the patient. These programming aides should meet certain basic requirements to make them safe, efficient, and easy to use. One such system designed by ELA Médical, "Programming Assistant" is herein described. The preliminary results of an initial study on the acceptance of this programming aide among physicians involved in cardiac pacing are given and discussed.     

Ventricular Pacing from the Atrial Channel of a DDD Pacemaker: A Consequence of Pacemaker Twiddling?

ANDERSON, M.H., ET AL.: Ventricular Pacing from the Atrial Channel of a DDD Pacemaker: A Consequence of Pacemaker Twiddling? The breakdown of pacemaker lead insulation under conditions of mechanical stress leading to failure of pacing is well recognized. We present a case where adjacent breakdown of insulation in two unipolar pacing leads resulted in inappropriate ventricular pacing. Replacement of the leads rectified the problem. [PACE, Vol. 13, December, Part I 1990)     

Torsades de Pointes: A Rare Complication of Temporary Pacing for Permanent Ventricular Pacemaker Failure

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 a defective permanent ventricular pacemaker, this potentially fatal arrhythmia may occur as a complication of interaction between the two pacemakers.     

A New Motion Responsive Pacemaker: First Clinical Experience with an Acceleration Sensor Pacemaker

A new accelerometer-based adaptive rate pacemaker (OEXCELVR^TM) was evaluated to investigate its behavior at nominal settings during treadmill exercise testing and postural changes. Eight patients with sinus rhythm were selected to compare intrinsic heart rate to sensor mediated rate. Throughout exercise treadmill testing, changes in the sensor mediated rate closely paralleled actual physiological changes. The Pearson product moment correlation of pacing rate with sinus frequency, calculated for all patients, was r = 0.82 (P = 0.001). Change in the patient's physical position resulted in immediate change in sensor rate, which corresponded appropriately to the type of position change and activity level. Average (± SD) pacing rate was 62.4 ± 2.7 beats/min supine; 67 ± 3.8 beats/min sitting; 69.8 ± 6.4 beats/min standing; 81.6 ± 8.7 beats/min slow walking; and 96.8 ± 1.3 beats/min fast walking. After 4 minutes of recovery, the average pacing rate dropped to 65 ± 3 beats/min. The interaction between the accelerameter and the pulse generator at nominal settings was accurate and infrequently required the use of its many programming options. The accelerometer sensor and pulse generator algorithm in this device during postural change and exercise resulted in physiological-like changes in sensor mediated heart rate.     

Spontaneous Heart Activity in Pacemaker Treated Patients with High-grade Atrioventricular Block A Holter Monitor Study

A Holter monitor study. A Holter monitor study was performed to assess the occurrence of spontaneous heart activity in 70 pacemaker treated patients (mean age 72.1 years) with high-grade atrioventricular (AV) block, who had been treated with permanent pacemakers for a mean of 60 months (range 5-161). Nineteen patients had asynchronous (VOO), and 51 QRS-inhibited (VVI) pacemakers. The patients were monitored for a mean of 23 hours (range 15.5-26). Twenty-five patients were re-studied for day-by-day variations in spontaneous heart activity. At clinical observation, thirty-eight patients had pacemaker rhythm only. During monitoring, all patients studied had some kind of spontaneous cardiac activity, mostly ventricular ectopic beats. Three patients had short episodes of sinus rhythm of more than 70 beats/min. Patients in functional class III-IV (NYHA) or with an enlarged heart had the most spontaneous heart activity; those with asynchronous pacemakers had the least spontaneous cardiac activity. No tachyarrhythmias precipitated by interference between intrinsic heart beats and asynchronous pacemakers were seen. Twenty patients studied twice had a relatively stable occurrence of spontaneous heart activity, while five (20%) varied considerably. On the basis of these long-term observations it is difficult to predict when interference rhythm will occur, and asynchronous pacemakers therefore cannot be recommended for the first implantation. (PACE, Vol. 4, November-December, 1981)     

Peritoneal Migration of an Abdominally Implanted Epicardial Pacemaker: A Cause of Intestinal Obstruction

We report the case of a 10-year-old child with an abdominally implanted epicardial pacemaker that eroded through the peritoneum and migrated to an intraperitoneal location, resulting in partial and then complete intestinal obstruction. This potentially life-threatening complication should be considered when a patient with an abdominally implanted pacemaker presents with abdominal pain.     

Pacemaker Architecture: A Pacemaker with an Attached Computer or a Computer with an Attached Pacemaker

Les microprocesseurs ont une importance majeure dans la téchnologie des stimulateurs cardiaques. Le développement de systèmes adaptatifs capables de répondre aux variables physiologiques va au bout du compte améliorer les qualityés des soins prodigués à chaque patient. Quoi qu'il en soit et dans le but de minimiser la consommation d'énéergie, il sera nécessaire d'incorporer certaines fonctions dans le boitier, en dehors du microprocesseur. Un langage spécifique supplémentaire peut, de plus, devenir nécessaire.     

Demonstration of the Feasibility of Implantation of a Skeletal Muscle Pulse Generator for Fecal Incontinence in a Patient with an Implanted Unipolar DDD Pacemaker

Electromagnetic fields and myopotentials from skeletal muscle may interfere with the function of a cardiac pacemaker. A 65-year-old woman with a unipolar DDD cardiac pacemaker underwent dynamic graciloplasty (transposition of the gracilis muscle around the anal canal and subsequent implantation of a bipolar pulse generator to stimulate the gracilis muscle), for the treatment of fecal incontinence. This gracilis pulse generator is turned "off" with an external magnet to allow defecation. Appropriate functioning of these two pulse generators (the cardiac pacemaker and the gracilis pulse generator) was tested during implantation of the gracilis pulse generator and afterwards. It was demonstrated that the combination could be used safely in this patient.     

A New System for Follow-Up Patients with Permanent Pacemakers

BROFFONI, T., ET AL.: A New System for Follow-Up Patients with Permanent Pacemakers. The use of a new computerized system for coordinating technical and clinical data and especially for filing the parameters found during out-patient checkups enables us to rationally carry out follow-up of approximately 900 patients with pacemakers in our electrostimulation laboratory without wasting time or data. The system is composed of a personal Olivetti M240 computer, with a 20 Bbyte and 640 Kram hard disk, an analog-digital interface and a personalized data base for coordinating and filing the parameters found. The type of pacemaker implanted (monocameral, dual chamber or rate responsive) is of no consequence to the system that is based on the acquisition of the surface electrocardiogram. A comparison of the filed data on printouts or graphs allows us to note every type of misfunction or anomaly in the stimulation system in real time.