What can be the possible directions for cardiac axis?
-30° to +110°
Between whch limbs is the potential difference measured with the standard limb leads I/II/III?
I: right and left arm
II: right arm and left leg
III: left arm and left leg
What is the effect of stophaninge-G on the stimulus conduction in the AV node?
delays stimulus - negative dromotrophic
List the main steps of determining the cardiac axis
- measure R-wave in each lead
- construct vectors
- direction of integral vector = cardiac axis
Where is Epinephrine produced?
adrenal medulla
What type of acetylcholine receptors are present in the heart?
muscarinic Ach receptors
What type of ionchannels does Verpamil block?
Ca2+ channels
List 4 of the effects of the acetylcholine on the heart
- negative chronotrophic effect
- negative bathmotrophic effect
- negative dromotrophic effect
- negative inotrophic effect
Why does Atropine inhibit the acetylcholine effect on the muscarine Ach receptors?
Atropin binds to the receptors without stimulating
Describe a normal PQ segment
Action potential through AV, not enough to create detectable differences - isoelectric line
How can the hardness of the pulse be determined?
the power needed to compress it
List the reg. waves in the ECG of dogs
P, Q, R, S T
Effect of Epinephrine
- positive chronotrphic effect
- positive bathmotropic effect
- positive dromotrophic effect
- positive inotrophic effect
Antagonist of Epinephrine
Propanolol
Positive waves of ECG in human?
P, R and T
Negative waves of the cardiac cycle?
Q, S, and T (except in human and ca.)
