Anatomic localization and autonomic modulation of atrioventricular junctional rhythm in failing human hearts

Vadim V. Fedorov, Christina M. Ambrosi, Geran Kostecki, William J. Hucker, Alexey V. Glukhov, Joseph P. Wuskell, Leslie M. Loew, Nader Moazami, Igor R. Efimov*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

35 Scopus citations


Background-The structure-function relationship in the atrioventricular junction (AVJ) of various animal species has been investigated in detail; however, less is known about the human AVJ. In this study, we performed high-resolution optical mapping of the human AVJ (n=6) to define its pacemaker properties and response to autonomic stimulation. Methods and Results-Isolated, coronary-perfused AVJ preparations from failing human hearts (n=6, 53±6 years) were optically mapped using the near-infrared, voltage-sensitive dye, di-4-ANBDQBS, with isoproterenol (1 μmol/L) and acetylcholine (1 μmol/L). An algorithm detecting multiple components of optical action potentials was used to reconstruct multilayered intramural AVJ activation and to identify specialized slow and fast conduction pathways (SP and FP). The anatomic origin and propagation of pacemaker activity was verified by histology. Spontaneous AVJ rhythms of 29±11 bpm (n=6) originated in the nodal-His region (n=3) and/or the proximal His bundle (n=4). Isoproterenol accelerated the AVJ rhythm to 69±12 bpm (n=5); shifted the leading pacemaker to the transitional cell regions near the FP and SP (n=4) and/or coronary sinus (n=2); and triggered reentrant arrhythmias (n=2). Acetylcholine (n=4) decreased the AVJ rhythm to 18±4 bpm; slowed FP/SP conduction leading to block between the AVJ and atrium; and shifted the pacemaker to either the transitional cell region or the nodal-His region (bifocal activation). Conclusions-We have demonstrated that the AVJ pacemaker in failing human hearts is located in the nodal-His region or His bundle regions and can be modified with autonomic stimulation. Moreover, we found that both the FP and SP are involved in anterograde and retrograde conduction.

Original languageEnglish (US)
Pages (from-to)515-525
Number of pages11
JournalCirculation: Arrhythmia and Electrophysiology
Issue number4
StatePublished - Aug 2011


  • Atrioventricular node
  • Heart failure
  • His bundle
  • Junctional rhythm
  • Optical mapping

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)


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