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Published on: April 26, 2015
Mechanisms of resetting reentrant circuits in canine ventricular tachycardia
M S Hanna1, J Coromilas, M E Josephson
1Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA, USA. mhanna@mail.med.upenn.edu
Background:
Resetting has been used to characterize reentrant circuits causing clinical tachycardias.
Methods And Results:
To determine the mechanisms of resetting, sustained ventricular tachycardia was induced in dogs with 4-day-old myocardial infarctions by programmed stimulation. Premature stimulation was accomplished from multiple regions within reentrant circuits; resetting curves were constructed and compared with activation maps. Monotonically increasing responses, or a "mixed" response (increasing portion preceded by a flat portion), occurred. All reentrant circuits had a fully excitable gap. Interval-dependent conduction delay and concealed retrograde penetration led to increased resetting response curves.
Conclusions:
Multiple mechanisms revealed by mapping cause resetting of reentrant circuits.
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