[Selective activation of fast and slow electrogenesis of cardiac membranes in the excitable period of the cardiac cycle].
Two types of electrogenic alterations of cardiac cell membranes during vulnerability are shown. The first one: selective activation only of slow response close to the source of miocardium stimulation and a simultaneous appearance of an extrasystolic impulse of great latency (100 ms and more) far from the source of stimulation. Extrasystolic latency is considered as the time of slow response propagation. Slow propagation is due to the small size of reentry during vulnerability. The second one: selective activation only of fast Na channels leads to generation of a very short response (10-20 ms duration)--cardiac spike. Appearance of such a spike is also favourable for reentry during vulnerability.
D000200:Action Potentials; D000818:Animals; D002415:Cats; D004285:Dogs; D006329:Heart Conduction System / Q000502:physiology*; D066298:In Vitro Techniques; D009200:Myocardial Contraction; D011930:Reaction Time; D012964:Sodium / Q000378:metabolism
D012964:Sodium
Izbiratel'noe aktivirovanie bystrogo i medlennogo élektrogeneza serdechnykh membran v uiazvimyĭ period serdechnogo tsikla.