Cardiac Action Potential Flashcards
(25 cards)
Ventricular action potential has … phases
4phases 0 1 2 3 4
Phase 0 is …
Caused due to….
Early depolarisation
Na+ influx
Phase 1
Early repolarization
K+ efflux
Phase 2
Plateau phase
K+ efflux= Ca+ influx(L-type)
Ltype Ca+ closes at the end of phase2
Phase3
Late repolarization
K+ efflux
Phase4
Resting membrane potential
Na+ —k+ pump
Dromotropy
Property of conduction
Chronotropy
Heart rate
Inotropy
Myocardial contractility
Ventricular action potential
Bathmotropy
Cardiac excitability
Lucitropy
Cardiac relaxation
Sa node responsible for ….
Automacity
Automacity?
Ability to generate impulse even in the absence of external stimulus
Sa nodal potential( max)
100/min
….. reduces Sa nodal potential from 100 to 72/min
Parasympathetic system
Via resting vagal tone
Name the automatic tissues
Sa node
Av node
His- purkinje system
Atrial cells near ostium of coronary sinus
Sa node action potential also known as
Pacemaker potential
Pre potential
Restless membrane potential spontaneous diastolic depolarization
Slow response action potential
Moat imp parameter that determine slope of action potential
Ans- autonomic nervous system
Vaughan william classifn of antiarrhythmic drjg has … classes
Class 1,2,3,4
Class 1 are … blockers and divided into…..
Na+ channel blockers
Divided into Ia, Ib, Ic
Class2 are…
Aact on….
Beta blockers
Phase 4
Class3 are …. blockers
Act by….
k+ channel blockers
Prolongs QT
Eg.s for class3
BIDAS Bretylium Ibutilide Dofetilide Amiodarone Sotalol
Wat is sotalol
Antiarryhthmic agent action via K+ channel blocker predominantly
