Document Detail


Paced beats following single nonsensed complexes in a "codependent" cardioverter defibrillator and bradycardia pacing system: potential for ventricular tachycardia induction.
MedLine Citation:
PMID:  1719506     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Patients with implantable defibrillators often require bradycardia pacemakers. Adverse interactions between separate defibrillator and bradycardia pacing units have occurred, including failure to detect ventricular fibrillation due to persistent bradycardia pacing during the arrhythmia. A device with combined bradycardia pacing and antitachycardia therapy capability may obviate adverse device interactions. We describe a previously unrecognized phenomenon that may occur in a combined device when the algorithms for sensing bradycardia and tachycardia are "codependent"; that is, the circuitry for brady- and tachyarrhythmia detection relies on the same automatic gain sense amplifier. Three of 37 patients in whom the device was implanted had ventricular tachycardia initiated when bradycardia pacing stimuli were delivered by the device after probable nonsensed sinus beats. In each case, nonsensed beats appeared to have a markedly diminished amplitude, occurred after ventricular premature depolarizations that produced large amplitude electrograms, and had an electrogram morphology that matched that of sinus rhythm. In each case, the bradycardia pacing interval was at least 1,200 msec (range 1,200 to 1,714 msec). In two of the three patients, large amplitude ventricular premature depolarizations or nonsustained ventricular tachycardia caused an adjustment of the gain control that potentiated the failure to sense the subsequent lower amplitude signal. In all three patients, the induced arrhythmia was rapidly terminated by pacing or cardioversion. Decreasing the bradycardia pacing interval by 110-514 msec has prevented recurrence during short-term follow-up. Our findings suggest that codependent bradycardia and antitachycardia devices may have their own unique potential difficulties in adapting to rapid changes in rate and signal amplitude.
Authors:
D J Callans; B G Hook; F E Marchlinski
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Publication Detail:
Type:  Case Reports; Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Pacing and clinical electrophysiology : PACE     Volume:  14     ISSN:  0147-8389     ISO Abbreviation:  Pacing Clin Electrophysiol     Publication Date:  1991 Aug 
Date Detail:
Created Date:  1991-11-27     Completed Date:  1991-11-27     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  7803944     Medline TA:  Pacing Clin Electrophysiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1281-7     Citation Subset:  IM    
Affiliation:
Clinical Electrophysiology Laboratory, Hospital of the University of Pennsylvania, Philadelphia 19104.
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MeSH Terms
Descriptor/Qualifier:
Aged
Bradycardia / physiopathology,  therapy*
Electric Countershock*
Electrocardiography
Humans
Male
Pacemaker, Artificial*
Prostheses and Implants*
Tachycardia / etiology*,  physiopathology,  therapy
Grant Support
ID/Acronym/Agency:
HL24278/HL/NHLBI NIH HHS; HL28093/HL/NHLBI NIH HHS

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


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