ECG 1

Question 1

SA node is the originating focus from the _____?

Answer 1

SA node

Question 2

the absence of atrial pacemaker activity will result in the absence of a P-wave, this is called?

Answer 2

sinus pause

sinus arrest

Question 3

the ultimate sinus node dysfunction is?

Answer 3

asystole

Question 4

this is dysfunction of the SA node from aging and of the atrial myocardium

also sinus node fibrosis is due to intermittent episodes of tachycardia and severe bradycardia

Answer 4

sick sinus syndrome aka: Tachy Brady syndrome

Question 5

impulses originate from? and then spread anterograde through what bundle?

Answer 5

sinus node

Bachman’s bundle to the left atrium and through internal pathways to the AV node

Question 6

any cell of the heart can, under certain circumstances, initiate an impulse where?

Answer 6

atrium
AV node
ventricle

Question 7

this is an example of an ectopic automatically focus

different atrial ectopic foci fire impulses antegrade to the AV node then to His bundles, the bundle branch and then the purkinje fibers

three different P wave morphologies followed by a QRS

Answer 7

wandering atrial pacemaker

Question 8

sinus node?
atrial muscle?
AV node?
ventricular muscle?

Answer 8

60-100 bpm
60 bpm
40-60 bpm
20-40 bpm

Question 9

normally, the impulses from the SA node suppress the emergence of ectopic foci which have lower inherent rates of automaticity?

Answer 9

overdrive suppression

Question 10

there are two conditions in which ectopic automaticity foci have loss of overdrive suppression:

• failure of the original focus
• block of transmission of the original focus

resulting in:

Answer 10

an escape beat or escape rhythm