| Autor: |
Castellanos A; Department of Medicine, University of Miami School of Medicine, Florida 33101., Mendoza IJ, Saoudi N, Jalife J |
| Jazyk: |
angličtina |
| Zdroj: |
Pacing and clinical electrophysiology : PACE [Pacing Clin Electrophysiol] 1988 Sep; Vol. 11 (9), pp. 1291-5. |
| DOI: |
10.1111/j.1540-8159.1988.tb03990.x |
| Abstrakt: |
A patient had ventricular tachycardia with cycle lengths consistently varying between 400 and 490 ms. Arrhythmias with a similar electrocardiographic pattern had been thought to result from the regular activity of an automatic pacemaker with either 3:2 exit block of the Wenckebach type or alternation in exit conduction times. However, the findings in our patient could also be explained by postulating the existence of modulated ventricular parasystole having 3:2 exit block or with alternating (short-long) exit conduction times. In either case, the action potentials elicited by the parasystole must have reached (with variable delays) the ventricular tissue beyond the zone of protection to produce electrotonic depolarizations which, in turn, were reflected back to the ectopic focus itself. This resulted in runs of 2:3 or 2:2 "self-entrainment" of the parasystolic pacemaker. Similar phenomena have been produced in biologic and mathematical models of modulated parasystole. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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