Timing Cycles

David L. Hayes, Paul J. Wang, Samuel J. Asirvatham, Paul A. Friedman

Research output: Chapter in Book/Report/Conference proceedingChapter

3 Scopus citations


Understanding the basic timing cycles of each pacing mode and the function and interaction of all components of a timing cycle is critical to interpreting the electrocardiogram of a patient with a pacemaker, implantable cardioverter-defibrillator (ICD) or cardiac resynchronization therapy (CRT) device. Although these devices continue to become more sophisticated even the most complex device and associated electrocardiographic tracing can be interpreted if the basic timing cycles and parameters are understood. This chapter initially goes through individual pacing modes, followed by an explanation of the different portions of the timing cycle including response to magnet application. The final portion of the chapter provides an approach to the biventricular paced electrocardiogram.

Original languageEnglish (US)
Title of host publicationCardiac Pacing, Defibrillation and Resynchronization
Subtitle of host publicationA Clinical Approach
Number of pages64
ISBN (Print)9780470658338
StatePublished - Dec 17 2012


  • AV (atrioventricular) interval and variations
  • Anodal stimulation
  • Atrial- and ventricular-based timing
  • Avoiding pace/sense competition
  • Biventricular V to V timing
  • Biventricular pacing percentage
  • Dual-chamber pacing
  • Mode-switching
  • Pacemaker-mediated tachycardia
  • Pacing mode(s)
  • Rate-adaptive pacing
  • Response to magnet application
  • Response to sudden bradycardia
  • Single-chamber pacing
  • Upper rate behavior
  • Ventricular pacing avoidance algorithms

ASJC Scopus subject areas

  • General Medicine


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