IBHRE FINAL PAPER COMPLETE
QUESTIONS AND ACCURATE SOLUTIONS
STUDY GUIDE
●● effective refractory period
Answer: the longest coupling interval to be associated with block
●● resting (transmembrane) potential
Answer: the voltage difference between the inside and outside of the cell
fiber (negative inside cell)
●● action potential
Answer: the cellular characteristics of depolarization and repolarization.
Consists of 5 phases (0-4)
●● Phase 0 of action potential
Answer: the depolarization phase. during this phase, th rapid sodium
channels are stimulated to open, causing the resting transmembrane
potential to spike from about -90 mV to about 0 mV.
●● Phase 1 of action potential
Answer: Early repolarization
,●● Phase 2 of action potential
Answer: the plateau phase. this phase, mediated by the slow calcium
channels, essentially disrupts and delays repolarization started in phase 1
and prolongs the refractory period
●● Phase 3 of action potential
Answer: the end of repolarization. Note: the period beginning at the end
of phse 0 through the end of phase 3 is the refractory period of cardiac
tissue. (opening of K+ channels, K+ out
(closing of ca+ channels))
●● Phase 4 of action potential
Answer: the resting phase. It is during this phase that, in some cardiac
cells, ions leak back and forth between membranes and cause a gradual
increase in the transmembrane (resting) potential.
●● Automaticity
Answer: The spontaneous depolarization to threshold, characteristic of
cardiac pacemaker cells.
●● AR interval
Answer: this begins when the atrial escape interval is allowed to time
out completely
, ●● Atrial escape interval
Answer:
●● AVRT (Atrioventricular reentrant tachycardia)
Answer: av conduction and accessory pathway create a reentrant circuit
causing tachycardia
●● AVNRT (AV nodal reentrant tachycardia)
Answer: This occurs when a reentrant circuit occurs in the AV node. A
premature beat reactivates the slow pathway and creates a loop with the
fast pathway after its refractory period. this rhythm accounts for 60% of
SVT and paroxysmal AT/AF. the rhythm will have a narrow QRS and
have a rate of about 150-200 bpm
●● AVNRT treatment
Answer: -Catheter ablation of the slow pathway
●● AVNRT - symptoms
Answer: palpitations, neck throbbing, polyuria, syncope
●● Adenosine with AVNRT
Answer: this helps differentiate AVNRT from AT. If AV block is
produced but A rhythm remains its AT
QUESTIONS AND ACCURATE SOLUTIONS
STUDY GUIDE
●● effective refractory period
Answer: the longest coupling interval to be associated with block
●● resting (transmembrane) potential
Answer: the voltage difference between the inside and outside of the cell
fiber (negative inside cell)
●● action potential
Answer: the cellular characteristics of depolarization and repolarization.
Consists of 5 phases (0-4)
●● Phase 0 of action potential
Answer: the depolarization phase. during this phase, th rapid sodium
channels are stimulated to open, causing the resting transmembrane
potential to spike from about -90 mV to about 0 mV.
●● Phase 1 of action potential
Answer: Early repolarization
,●● Phase 2 of action potential
Answer: the plateau phase. this phase, mediated by the slow calcium
channels, essentially disrupts and delays repolarization started in phase 1
and prolongs the refractory period
●● Phase 3 of action potential
Answer: the end of repolarization. Note: the period beginning at the end
of phse 0 through the end of phase 3 is the refractory period of cardiac
tissue. (opening of K+ channels, K+ out
(closing of ca+ channels))
●● Phase 4 of action potential
Answer: the resting phase. It is during this phase that, in some cardiac
cells, ions leak back and forth between membranes and cause a gradual
increase in the transmembrane (resting) potential.
●● Automaticity
Answer: The spontaneous depolarization to threshold, characteristic of
cardiac pacemaker cells.
●● AR interval
Answer: this begins when the atrial escape interval is allowed to time
out completely
, ●● Atrial escape interval
Answer:
●● AVRT (Atrioventricular reentrant tachycardia)
Answer: av conduction and accessory pathway create a reentrant circuit
causing tachycardia
●● AVNRT (AV nodal reentrant tachycardia)
Answer: This occurs when a reentrant circuit occurs in the AV node. A
premature beat reactivates the slow pathway and creates a loop with the
fast pathway after its refractory period. this rhythm accounts for 60% of
SVT and paroxysmal AT/AF. the rhythm will have a narrow QRS and
have a rate of about 150-200 bpm
●● AVNRT treatment
Answer: -Catheter ablation of the slow pathway
●● AVNRT - symptoms
Answer: palpitations, neck throbbing, polyuria, syncope
●● Adenosine with AVNRT
Answer: this helps differentiate AVNRT from AT. If AV block is
produced but A rhythm remains its AT
