Biomedical subjects

F Lindemans

Publications and source records attributed to F Lindemans.

3 recordsLinked to original sources

PubMed1988

The Activitrax rate responsive pacemaker system.

Bipolar Medtronic Activitrax rate responsive pacemakers were implanted in 31 patients for ventricular (28) or atrial (3) pacing. Mean follow-up was 16 months (range 10 to 26). Twenty pacemakers were implanted after catheter ablation of the His bundle, 7 for sick sinus syndrome. 1 for atrioventricular block and 3 for sick sinus syndrome with atrioventricular block. A rate response value was selected that gave a pacing rate of about 100 pulses/min during walking. Of the 31 patients, all had 24-hour ambulatory electrocardiographic monitoring with diary, 11 walked a 20-minute circuit, including a flight of stairs, and 20 had a treadmill exercise test. In 9 patients the pacing rate could be compared with the underlying sinus rate during exercise and was seen to match it very closely. In 12 patients the pacing rate during car driving was found to be similar to the sinus rate of 5 volunteers under similar conditions (mean minimum and maximum rate was 80 and 99 pulses/min, respectively). No pacing-induced arrhythmias were seen during ambulatory electrocardiographic monitoring. At high pacing rates slightly irregular pacing intervals were sometimes observed, which was due to polarization sensing. Sporadically, 1 pacing interval shortened to the upper rate value, because of a known and now resolved timing anomaly. Neither anomaly was of clinical consequence and the first could be resolved by reprogramming.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1984

Management of pacemaker circus movement tachycardias.

DDD pacemakers were implanted in 11 patients of whom 5 had the capacity to conduct retrogradely to the atrium. Methods to prevent or terminate pacemaker circus movement tachycardia ( PCMT ) were evaluated in these patients. V-A conduction was assessed before implantation by incremental right ventricular pacing while recording right atrial electrograms. Following implantation and at quarterly outpatient clinic visits, V-A conduction and ability to initiate and sustain PCMT were systematically assessed by non-invasive techniques. PCMT could be induced non-invasively in all 5 patients. The methods used to reduce and terminate the incidence of PCMT were: 1) decreasing the atrial sensitivity; 2) stressing the V-A conduction system by programming a high upper rate with an appropriately short A-V interval; 3) programming a low lower rate; 4) avoiding the Wenckebach response (by programming a high upper rate); 5) medication; and 6) occasionally by using a magnet. PCMT was controlled in all patients, in 2 patients by programming measures only and in 2 with the addition of medication. One patient who refused medication had to be programmed into another pacing mode. We conclude that: 1) the presence of V-A conduction is not an absolute contraindication to the use of a DDD pacing system; 2) pacing the ventricle early enough to cause V-A block was the most useful method to terminate PCMT ; 3) future generation DDD pacemakers should prevent initiation of PCMTs while maintaining the possibility to synchronize to exercise-induced high atrial rates.

Adult↗

PubMed1984

Clinical experience with implantable devices for control of tachyarrhythmias.

Pacing is becoming an accepted form of treatment for reentry tachycardias. The different pacing modalities available and experience with a patient-activated antitachycardia pacemaker are presented in this paper. This system has bidirectional communication between pacemaker and pacemaker-activator and between pacemaker and prescription formulator (which is a sophisticated portable stimulator used for non-invasive electrophysiological evaluation of the system). This pacemaker was implanted in 18 patients with drug-resistant tachycardias. Six patients had ventricular tachycardia, 3 had A-V nodal reentrant tachycardia, 4 had the concealed accessory pathway, and 5 had the WPW syndrome. In the 3 months before implantation the mean number of admissions for termination of tachycardia was 2.1 per patient-month. During a follow-up period of 3-26 months only 6 patients were admitted once for termination of tachycardia (0.02 admissions per patient-month). The reasons for admission of these 6 patients were: defective pacemaker activator in 2 patients, inadequate control of tachycardia in 2 patients, inappropriate use of the device in 1, and inadequate intake of medication in 1. All these problems were solved easily. Eight pacemaker activators required reprogramming, which was done in 5 patients on an out-patient basis. The interval scanning mode was used in 9 patients. Nine patients required more than 2 stimuli for reproducible termination. A step-wise increase in number of stimuli was used in 5 patients. This system has proven to be a safe and effective form of treatment of drug-resistant supraventricular and ventricular tachycardias and has resulted in marked improvement of the quality of life of these patients.

Adult↗