Repetitive Paroxysmal Tachycardia -- Mechanism and Control

Friday, March 13, 1998 - 9:30am - 10:30am
Keller 3-180
Leon Glass (McGill University)
Repetitive parosxysmal tachycardia is a term used by Parkinson and Papp in 1947 to describe the repeated initiation and termination of short episodes of rapid heart beats. I describe three different experimental models that show repeated bursts of relatively rapid activity: a ball of pacemaker cells that is stimulated at a fixed delay after an action potential; an experimental model of accessory pathway created by stimulating the atria at a fixed delay after activation of the ventricles; a preparation of cultured heart cells that shows spontaneous initiation and termination of rotating waves. These three systems share common properties of intrinsic pacemaking activity, a reentrant loop, and loss of excitability as a consequence of rapid activation. Based on the above mechanism, methods to control or eliminate the rhythm are immediately suggested.