| Autor: |
Begemann, Malcolm J. S., Bennekers, Johan H., Kingma, J. Herre, Lie, K. I. |
| Zdroj: |
Journal of Electrophysiology; Aug1987, Vol. 1 Issue 4, p350-356, 7p, 1 Chart, 5 Graphs |
| Abstrakt: |
A 20-year-old female with a left-sided concealed atrioventricular accessory pathway was studied during programmed stimulation to investigate the mechanisms of prevention of tachycardia by timed stimulation of the ventricle after a tachycardia initiating atrial extrastimulus. After the atrial tachycardia initiation zone was determined, the prevention zone of the ventricular stimulus was determined for each initiating interval. Two different prevention mechanisms were found, one whereby the ventricular depolarization was blocked retrogradely in the accessory pathway and another whereby the ventricular depolarization was conducted over the accessory pathway to the atrium but subsequently blocked anterogradely in the AV node. The preventive zone timed from the last ventricular complex to the ventricular stimulus was always greater than 30 msec whereby the minimum preventive interval was determined by the ventricular refractor}/ period. This could be of value when such a preventive algorithm is incorporated into a dual-chamber antitachycardia pacemaker. Knowing the exact mechanisms by which the prevention occurs allows one to predict how tachycardia can be prevented when the atrial extra beat originates from a different site and when the parameters of the heart are changed due to changes in autonomic tone or catecholamine level. [ABSTRACT FROM AUTHOR] |
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