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The Topaz model 515 (Vitatron B.V.) is a dual sensor rate responsive pacemaker for single chamber stimulation. It can be driven by activity counts (ACT) and QT interval measurements. Inappropriate rate modulation due to one sensor can be corrected by "sensor cross-checking." It was implanted in ten patients (20-86 years) of whom seven had complete heart block and atrial arrhythmias. After implantation T-wave amplitude ranged from 0.9 mV-3.5 mV. T-wave sensing ranged from 88%-99% in 9/10 patients at the follow-up of 3 weeks. Eight patients remained in default setting of the activity threshold, after evaluation with a short walking test. An exercise test was performed on all patients. In one test, QT sensing was marginal because of lead implantation in the right ventricular outflow tract. Therefore, this pacing rate was only modulated by ACT sensing. All others were tested with equal contribution of information from both sensors (ACT = QT). In 7/9, rate response was satisfactory. When the treadmill was repeated with ACT in five of these seven patients, rate generally accelerated too fast. In one patient the setting was adjusted to "QT > ACT," because of inappropriate acceleration due to activity sensing, in another it was adjusted to "QT < ACT" because of delayed response to activity. The pacing rate and the ACT during treadmill tests in "QT = ACT" mode were more closely correlated in the first 3 minutes, compared with the last 3 minutes. We feel that rate modulation with this new pacemaker is adequate. Sensor blending and sensor cross-checking are of clinical importance.
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L Jordaens
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Pacing and clinical electrophysiology : PACE,
F Provenier, and
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Pacing and clinical electrophysiology : PACE,
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The Veterinary record,
F Provenier, and
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E van Wassenhove, and
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L Jordaens
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Pacing and clinical electrophysiology : PACE,
F Provenier, and
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J Backers, and
E van Wassenhove, and
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L Jordaens
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Pacing and clinical electrophysiology : PACE,
F Provenier, and
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J Backers, and
E van Wassenhove, and
V de Meyer, and
L Jordaens
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Pediatrics international : official journal of the Japan Pediatric Society,
F Provenier, and
R van Acker, and
J Backers, and
E van Wassenhove, and
V de Meyer, and
L Jordaens
November 1994,
Pacing and clinical electrophysiology : PACE,
F Provenier, and
R van Acker, and
J Backers, and
E van Wassenhove, and
V de Meyer, and
L Jordaens
November 2010,
The Canadian journal of cardiology,
F Provenier, and
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J Backers, and
E van Wassenhove, and
V de Meyer, and
L Jordaens
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The American journal of cardiology,
