Premium
Rate Response of a Closed‐Loop Stimulation Pacing System to Changing Preload and Afterload Conditions
Author(s) -
CRON THOMAS A.,
HILTI PATRICK,
SCHÄCHINGER HARTMUT,
POUSKOULAS CHRISTOS D.,
KELLER DAGMAR I.,
ZAUGG CHRISTIAN E.,
BUSER PETER T.,
PFISTERER MATTHIAS E.,
OSSWALD STEFAN
Publication year - 2003
Publication title -
pacing and clinical electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.686
H-Index - 101
eISSN - 1540-8159
pISSN - 0147-8389
DOI - 10.1046/j.1460-9592.2003.t01-1-00218.x
Subject(s) - medicine , preload , cardiology , heart rate , afterload , blood pressure , contractility , cls upper limits , tachycardia , orthostatic vital signs , anesthesia , hemodynamics , optometry
Closed‐loop stimulation (CLS) is a new sensor concept for rate adaptive pacing measuring changes in the unipolar right ventricular impedance, which correlates to changes of the right ventricular contractility and reflects the autonomic nervous innervation of the heart. Some patients do not tolerate the CLS mode because of inappropriate tachycardia, mainly related to postural changes. This study tested if the rate response of the CLS sensor is influenced not only by myocardial contractility but also by rapid changes in right ventricular filling. In 12 patients (10 men, median age 77 years) with a Biotronik Inos 2 ‐CLS DDDR pacemaker and 14 controls (13 men, median age 59 years) head‐up tilt and handgrip testing was performed to provoke rapid changes in pre‐ and afterload. Tilting the pacemaker patients resulted in a nonphysiological steep increase of the sensor rate (increase >20 beats/min, peak after 1 minute, return to baseline within 2–3 minutes), which was significantly different from the control group, showing only a slight rise in intrinsic heart rate immediately after tilting. Simultaneously to the rapid increase in sensor rate, the pacemaker patients showed a marked orthostatic decline of systolic blood pressure. During handgripping, heart rate and blood pressure curves were similar in both groups. In patients with this CLS pacemaker, rapid preload reduction during head‐up tilting caused an overshooting sensor rate increase, reproducing the authors' clinical observation of postural pacemaker tachycardia in some patients. Consequently, they concluded that the rate response of the CLS pacing system can be inappropriately influenced by rapid shifts of blood volume, affecting right ventricular filling. (PACE 2003; 26[Pt. I]:1504–1510)