Spiral waves and reentry dynamics in an in vitro model of the healed infarct border zone

M. Roselle Abraham, Marvin G. Chang, Yibing Zhang, Connie Y. Chang, Linmiao Xu, Roland Emokpae, Leslie Tung, Eduardo Marbán

Research output: Contribution to journalArticlepeer-review

Abstract

RATIONALE:: Reentry underlies most ventricular tachycardias (VTs) seen postmyocardial infarction (MI). Mapping studies reveal that the majority of VTs late post-MI arise from the infarct border zone (IBZ). OBJECTIVE:: To investigate reentry dynamics and the role of individual ion channels on reentry in in vitro models of the "healed" IBZ. METHODS AND RESULTS:: We designed in vitro models of the healed IBZ by coculturing skeletal myotubes with neonatal rat ventricular myocytes and performed optical mapping at high temporal and spatial resolution. In culture, neonatal rat ventricular myocytes mature to form striated myocytes and electrically uncoupled skeletal myotubes simulate fibrosis seen in the healed IBZ. High resolution mapping revealed that skeletal myotubes produced localized slowing of conduction velocity (CV), increased dispersion of CV and directional-dependence of activation delay without affecting myocyte excitability. Reentry was easily induced by rapid pacing in cocultures; treatment with lidocaine, a Na + channel blocker, significantly decreased reentry rate and CV, increased reentry pathlength and terminated 30% of reentrant arrhythmias (n=18). In contrast, nitrendipine, an L-type Ca channel blocker terminated 100% of reentry episodes while increasing reentry cycle length and path length and decreasing reentry CV (n=16). K + channel blockers increased reentry action potential duration but infrequently terminated reentry (n=12). CONCLUSIONS:: Cocultures reproduce several architectural and electrophysiological features of the healed IBZ. Reentry termination by L-type Ca 2+ channel, but not Na + channel, blockers suggests a greater Ca-dependence of propagation. These results may help explain the low efficacy of pure Na + channel blockers in preventing and terminating clinical VTs late after MI.

Original languageEnglish (US)
Pages (from-to)1062-1071
Number of pages10
JournalCirculation research
Volume105
Issue number11
DOIs
StatePublished - Nov 2009

Keywords

  • Arrhythmia
  • Ca
  • Cardiac electrophysiology
  • Channels
  • Current
  • Electrophysiology
  • Mapping
  • Na
  • Optical mapping

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine

Fingerprint Dive into the research topics of 'Spiral waves and reentry dynamics in an in vitro model of the healed infarct border zone'. Together they form a unique fingerprint.

Cite this