This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Ciaccio, E. J. Search for Related Content PubMed PubMed Citation Articles by Ciaccio, E. J. Related Collections Arrythmias-basic studies Quantitative modeling Ablation/ICD/surgery

(Circulation. 2001;103:1017.)
© 2001 American Heart Association, Inc.

Basic Science Reports

Dynamic Relationship of Cycle Length to Reentrant Circuit Geometry and to the Slow Conduction Zone During Ventricular Tachycardia

Edward J. Ciaccio, PhD

From the Departments of Pharmacology and Biomedical Engineering, College of Physicians and Surgeons, Columbia University, New York, NY.

Correspondence to Edward J. Ciaccio, PhD, Department of Pharmacology, PH7W, Columbia University, 630 W 168th St, New York, NY 10032. E-mail ciaccio{at}columbia.edu

Background—Knowledge of cycle-to-cycle changes in isthmus geometry is of potential importance for radiofrequency catheter ablation to stop reentrant ventricular tachycardia. It was hypothesized that isthmus geometry often undergoes continuous evolution throughout reentry and that cycle-length variability measurements could be used to segment reentry into distinct phases and to predict changes in isthmus geometry.

Methods and Results—A canine infarct model of reentrant ventricular tachycardia in the epicardial border zone with a figure 8 pattern of conduction was used for analysis (25 monomorphic reentry episodes, 20 experiments). Tachycardias were segmented, on the basis of cycle-length variations, into 2 to 3 distinct phases corresponding to onset, maintenance, and spontaneous termination, when it occurred (6/25 episodes). Trends of linear cycle-length change occurred throughout the maintenance phase in all tachycardias. For each trend, quantitative geometric parameters of the isthmus were measured, and the following linear relationships were established. During a trend, the slow conduction zone activation interval and tachycardia cycle length increased, while isthmus length decreased. When isthmus length decreased, isthmus width decreased at its narrowed portion. Larger decreases in isthmus length corresponded to higher rates of linear cycle-length prolongation. Also, greater cycle-length variability tended to prolong tachycardia.

Conclusions—Cycle-length alterations occur throughout reentry in this canine model and are predictive of isthmus geometry changes. Because similar reentry dynamics, which affect catheter ablation efficacy, have been observed clinically, estimation of changes in geometry during electrophysiological study may help target ablation sites.

Key Words: catheter ablation • dynamics • electrophysiology • mapping • reentry

This article has been cited by other articles:

				E. J. Ciaccio Premature excitation and onset of reentrant ventricular tachycardia Am J Physiol Heart Circ Physiol, October 1, 2002; 283(4): H1703 - H1712. [Abstract] [Full Text] [PDF]

				E. J. Ciaccio, C. Costeas, J. Coromilas, and A. L. Wit Static Relationship of Cycle Length to Reentrant Circuit Geometry Circulation, October 16, 2001; 104(16): 1946 - 1951. [Abstract] [Full Text] [PDF]