Quantification of spatial inhomogeneity in conduction and initiation of reentrant atrial arrhythmias

W. J.E.P. Lammers, M. J. Schalij, C. J.H.J. Kirchhof, M. A. Allessie

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142 Citations (Scopus)


In isolated superfused left atria of the rabbit, inhomogeneity in conduction was quantified using the activation times measured with a high-density mapping system. At each recording site, the maximal difference with neighboring activation times (i.e., phase difference) was calculated. Local phase differences were plotted in a phase map, revealing the spatial distribution of inhomogeneities in conduction, and from each map a total index of inhomogeneity was calculated. During slow pacing (2 Hz) local differences in conduction velocity, depending on the direction of propagation, were found already. Inhomogeneity in conduction increased significantly during single early premature beats (inhomogeneity index increased from 2.3 to 3.1; P < 0.001). The application of multiple premature beats further increased inhomogeneity in conduction, whereas rapid pacing induced the highest level of inhomogeneity (inhomogeneity index 5.3; P < 0.001). An analysis of the spatial distribution of maximal phase differences revealed that during premature beats inhomogeneities in conduction were limited to an area of 6 mm around the point of origin of the premature impulse, whereas during rapid pacing inhomogeneities in conduction were found throughout the whole preparation. Phase maps constructed during the initiation of reentrant tachyarrhythmias showed that reentry occurred at sites with the highest phase differences. Quantification of spatial inhomogeneities in conduction is a useful tool to evaluate the vulnerability of the myocardial substrate for reentrant arrhythmias.

Original languageEnglish
Pages (from-to)H1254-H1263
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Issue number4 28-4
Publication statusPublished - 1990
Externally publishedYes


  • pacing
  • phase differences
  • reentry
  • unidirectional block

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)


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