Cardiology Basic Anatomy Review

Question 1

Name three branches of the right coronary artery:

Answer 1

• Right Marginal Artery (acute marginal branches)
• Atrioventricular (AV) nodal artery
• Posterior interventricular artery (posterior descending artery)

Question 2

Name the 2 main branches of the left main coronary artery and their subbranches:

Answer 2

• Left anterior descending artery (septal branches and diagonal branches)
• Left circumflex artery (obtuse marginal branches)

Question 3

Dominance of circulation refers to what?

Answer 3

The main coronary artery that supplies the posterior descending artery (right dominant circulation, left dominant circulation or balanced circulation)

Question 4

Approximately 80% of people have what dominance of circulation pattern?

Answer 4

About 80% of the population have their posterior interventricular artery and at least one posterolateral branch arising from their right coronary artery and are said to have right-dominant circulation.

Question 5

Approximately 15% of people have what dominance of circulation pattern?

Answer 5

About 15% of the population have their posterior interventricular artery and at least one posterolateral branch arising from their left circumflex artery and are said to have left-dominant circulation.

Question 6

Approximately 5% of people have what dominance of circulation pattern?

Answer 6

About 5% of the population have their posteroinferior left ventrical supplied from both their right coronary artery and left circumflex artery. This dual supply is referred to as balanced circulation.

Question 7

What proportion of the population have:

• right dominant circulation
• left dominant circulation
• dual circulation?

Answer 7

80% have right dominant

15% have left dominant and 5% have balanced circulation

Question 8

The sinoatrial node is supplied by which artery?

Answer 8

The SA nodal artery

Question 9

The SA nodal artery arises from which coronary artery in which proportion?

Answer 9

The SA nodal artery arises from the RCA 60% of the population and from the LCA in 40% of people.

Question 10

Where does the majority of cardiac venous blood drain to and via what pathway?

Answer 10

Most venous blood from the heart drains into the RA through the coronary sinus.

Question 11

What vessels contribute to the heart’s physiological R-L shunt?

Answer 11

The thesbian veins (The smallest cardiac veins or Thebesian veins or veins of Thebesius or vessels of Thebesius or vasa Thebesii are minute valveless veins in the walls of all four heart chambers.).

A small amount of venous blood drains through thesbian veins into all four chambers, contributing to the physiologic R-L shunt

Question 12

What keeps the atria electrically isolated from the ventricles?

Answer 12

The annulus fibrosis cordis (fibrous skeleton) except when accessory pathways are present.

Question 13

Which parts of the cardiovascular system are innervated with sympathetic nerves?

Answer 13

SA node, AV node, ventricular myocardium and vasculature

Question 14

Which sympathetic fibres/receptors increase chronotropy (pacemaker activity)?

Answer 14

Beta1 fibres in the SA node

Question 15

Which sympathetic fibres/receptors increase inotropy (contractility)?

Answer 15

B1 fibres in cardiac muscle to help increase CO

Question 16

What does stimulation of Beta1 and Beta2 fibres in the skeletal and coronary circulation cause?

Answer 16

Vasodilatation

Question 17

What does parasympathetic activation of the heart result in?

Answer 17

Basal vagal tone dominates the tonic sympathetic stimulation of the SA and AV node resulting in slowing of pacemaking activity and conduction

Question 18

Which parts of the cardiovascular system are innervated with parasympathetic nerves?

Answer 18

SA node, AV node, atrial myocardium but few vascular beds

Question 19

Sympathetic or parasympathetics have the most impact on total peripheral vascular resistance?

Answer 19

Sympathetics cause vasodilalation whereas parasympathetics have very little impact.

Question 20

The LBB branches off into what?

Answer 20

Posterior and anterior fascicle.

Question 21

ECG:
On the horizontal axis, 1 small square (1mm) represents how much time?
One large square (5mm) represents how much time?
Note: paper speed is 25mm/sec

Answer 21

1 small square is 40msec

1 large square is 200msec

Question 22

ECG:
On the vertical axis, 1 small square (1mm) represents what voltage?
TWO large squares (10 mm) represents what voltage?

Note: at standard gain setting

Answer 22

1 small square is 0.1 mV

2 large squares is 1mV

Question 23

ECG:

On a standard 12-lead ECG, what are the names of the limb leads and the precordial leads?

Answer 23

Limb leads: I, II, III, aVL, aVR, AVF

Precordial leads: V1-V6

Question 24

ECG:

Where are the precordial leads placed?

Answer 24

V1 and V2: right and left of septum
V3 and V4: anterior
V5 and V6: lateral

Question 25

ECG:

Which leads may be useful for RV infarction and dextrocardia?

Answer 25

V3R-V6R

Question 26

ECG:

Right sided leads are useful in what conditions?

Answer 26

RV infarction and dextrocardia

Question 27

What is a normal heart rate in beats per minute?

Answer 27

60-100 bpm

Question 28

ECG: What atrial rate constitutes paroxysmal tachycardia?

Answer 28

150-250bpm

Question 29

ECG: What atrial rate constitutes atrial flutter?

Answer 29

250-350bpm

Question 30

ECG: What atrial rate constitutes atrial flutter?

Answer 30

<350bpm

Question 31

ECG:

How do you calculate the rate off an ECG reading with a regular rhythm?

Answer 31

1. Count the number of large squares between 2 QRS complexes
2. Divide 300 by this number

(300-150-75-60-50-43)

Question 32

ECG:

How do you calculate the rate off an ECG reading with a irregular rhythm?

Answer 32

Rate = 6 x number of R-R intervals in 10 seconds (the rhythm strips are 20 second recordings)