Document Detail

Atrial arrhythmia management with sensor controlled atrial refractory period and automatic mode switching in patients with minute ventilation sensing dual chamber rate adaptive pacemakers.
MedLine Citation:
PMID:  1383962     Owner:  NLM     Status:  MEDLINE    
Although a long postventricular atrial refractory period (PVARP) may prevent the occurrence of pacemaker mediated tachycardias and inadvertent tracking of atrial arrhythmias in dual chamber (DDD) pacing, the maximum upper rate will necessarily be compromised. We tested the feasibility of using minute ventilation sensing in a dual chamber rate adaptive pacemaker (DDDR) to shorten the PVARP during exercise in 13 patients with bradycardias (resting PVARP = 463 +/- 29 msec) to avoid premature upper rate behavior. Graded treadmill exercise tests in the DDD and DDDR modes at this PVARP resulted in maximum ventricular rates of 98 +/- 8 and 142 +/- 3 beats/min, respectively (P < 0.0001), due to chronotropic incompetence and upper rate limitation in the DDD mode, both circumvened with the use of sensor. In order to stimulate atrial arrhythmias, chest wall stimulation was applied for 30 seconds at a rate of 250 beats/min at a mean unipolar atrial sensitivity of 0.82 mV. Irregular ventricular responses occurred in the DDD mode (the rates at a PVARP of 280 and 463 +/- 29 msec were, respectively 92 +/- 5 and 66 +/- 3 msec; P < 0.0001). In the DDDR mode at a PVARP of 463 +/- 29 msec, regular ventricular pacing at 53 +/- 2 beats/min occurred due to mode switching to VVIR mode in the presence of repetitive sensed atrial events within the PVARP. One patient developed spontaneous atrial fibrillation on follow-up, which was correctly identified by the pacemaker algorithm, resulting in mode switch from DDDR to regular VVIR pacing and preservation of rate response. In conclusion, sensor controlled PVARP allows a long PVARP to be used at rest without limiting the maximum rate during exercise. In addition, to offer protection against retrograde conduction, a long PVARP and mode switching also limit the rate during atrial arrhythmias and allow regular ventricular rate responses according to the physiological demands.
C P Lau; Y T Tai; P C Fong; J P Li; F L Chung
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Pacing and clinical electrophysiology : PACE     Volume:  15     ISSN:  0147-8389     ISO Abbreviation:  Pacing Clin Electrophysiol     Publication Date:  1992 Oct 
Date Detail:
Created Date:  1992-11-25     Completed Date:  1992-11-25     Revised Date:  2004-11-17    
Medline Journal Info:
Nlm Unique ID:  7803944     Medline TA:  Pacing Clin Electrophysiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1504-14     Citation Subset:  IM    
Department of Medicine, University of Hong Kong, Queen Mary Hospital.
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MeSH Terms
Atrioventricular Node / physiopathology
Bradycardia / physiopathology,  therapy*
Cardiac Pacing, Artificial / methods*
Equipment Design
Exercise / physiology
Exercise Test
Heart Block / physiopathology,  therapy*
Pacemaker, Artificial*
Tachycardia / prevention & control

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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