H G De Boer

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Electrophysiologic studies were performed before DDD pacemaker implantation in 50 patients with symptomatic heart block. The patients were separated into 2 groups. Group I consisted of patients with intact retrograde conduction and group II consisted of patients with blocked retrograde conduction. After pacemaker implantation, postventricular atrial(More)
Differential bipolar sensing was evaluated in 10 consecutive patients with symptomatic heart block managed with dual chamber pacing. During pacemaker implantation atrial and ventricular electrograms were recorded using unipolar (UP) and differential bipolar (DBP) sensing amplifiers. The mean peak-to-peak amplitudes of the UP and DBP atrial electrograms were(More)
In 14 patients with symptomatic sinus node dysfunction--sinus bradycardia, sino-atrial exit block, or sinus arrest--electrophysiological studies were performed before implantation of a pacemaker. In 8 patients incremental high right atrial pacing showed AV-nodal Wenckebach at pacing rates equal to or above 130/min (group I); in 6 patients AV-nodal(More)
We investigated the possibility to use the interval from an atrial stimulus to the ventricular R wave (A-R interval) as an indicator of physical stress, in 16 patients with pacemakers implanted for severe atrial bradycardia but with intact AV conduction. The A-R interval was studied during incremental atrial pacing at rest and during exercise with a(More)
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(More)
In this report we present the case of a patient with recurrent syncopal episodes. During one of the attacks the patient was monitored by telemetry and the ECG lead showed asystole for more than 7 seconds. As in cases of the cardioinhibitory type of hypersensitive carotid sinus syndrome (HCSS), asystole may represent suppression of the sinus node or(More)
A rate smoothing option is available in a new bipolar AV universal (DDD) pacemaker. In three patients, two with intact retrograde conduction and one with retrograde block, rate smoothing values of 3% and 6% were programmed. Irregular pacemaker-mediated tachycardia occurred in one patient and AV synchrony was temporarily lost in the other two patients. In(More)
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 this report we discuss(More)
A promising new pacemaker that provides on-line measurements of right ventricular (RV) impedance was evaluated in ten patients with symptomatic second- or third-degree atrioventricular (AV) block. We tested the assumption that if changes in RV impedance represented changes in RV stroke volume (SV), conditions known significantly to affect RV SV should be(More)
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