Prevalence of sensing abnormalities in dual chamber implantable cardioverter defibrillators

Mohammad Saeed, Anna Jin, Gregory Pontone, Steve Higgins, Michael Gold, David Harari, Steven Nunley, Mark S. Link, Munther K. Homoud, N. A.Mark Estes, Paul J. Wang

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


Background: The clinical efficacy of ICD therapy depends on accurate sensing of intracardiac signals and sensing algorithms. We investigated the occurrence of sensing abnormalities in patients with dual chamber ICDs. Methods: The study group consisted of all patients with dual chamber ICDs enrolled in the LESS trial and patients implanted with dual chamber ICDs at a single center between January 1997 and July 2000. Electrograms of spontaneous ventricular arrhythmias requiring device intervention were analyzed. Results: A total of 48 patients met the criteria for enrollment. Among the 244 episodes, 215 (88%) were due to ventricular tachycardia and 29 (12%) were due to ventricular fibrillation. Overall undersensing was infrequent with 12 (20%) patients exhibiting on average 2.2 undersensed beats during 26 episodes of ventricular arrhythmias. There was no delay in therapy due to undersensing. Oversensing occurred in 5 (10%) patients resulting in 13 (2.7%) episodes of inappropriate therapy. None of the patients had any lead abnormal ities and oversensing resolved after device reprogramming in 4 patients while 1 patient required a separate rate sensing lead. Among patients with oversensing, 4 out of 5 were pacing before the index event while among patients with no oversensing only 5 out of 42 were pacing (P < 0.001). Conclusions: Dual chamber ICDs demonstrate outstanding accuracy of sensing. However, because of the selection of patient population requiring more frequent pacing, oversensing occurs with a significant frequency. Meticulous evaluation in such patients is necessary to minimize the likelihood of oversensing and inappropriate shocks.

Original languageEnglish (US)
Pages (from-to)219-226
Number of pages8
JournalAnnals of Noninvasive Electrocardiology
Issue number3
StatePublished - Jul 2003


  • Implantable cardioverter defibrillator
  • Oversensing and undersensing
  • Ventricular arrhythmia

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)


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