Download Applied Anatomy of the Heart (syllabus and ICARS lecture - Wk 1-2

Applied Anatomy of the Heart (syllabus and ICARS lecture notes)
Understand the concepts & associated principles, functional &
clinical applications of:
1. Displacement of the apex beat; sternal thrust.
Apex Beat
Is the heart enlarged
Is the heart being pushed or pulled
Push: Tension pneumothorax or a space occupying lesion will push the heart
Pull: Pneumothorax or fibrosis can pull the heart across
Sternal Thrust Right Ventricular Hypertrophy
2. The degree of anastomosis of the coronary arteries and the effects of sudden vs gradual
occlusion.
Anastomoses of the coronary arteries are only potential anastomoses. Gradual coronary artery
disease can cause anastomoses between the Right and Left coronary arteries. However, Sudden
events such as thromo-emboli that block a substantial coronary artery will not allow for the
gradual anastomoses between R + L coronary arteries and necrosis from local ischaemia will
likely ensue. Anastomoses occur at the terminations of the coronary arteries, in the
atrioventricular groove, and between their interventricular branches, in the interventricular
groove.
3. The area of distribution of each coronary artery including the conducting tissue supplied
(noting that the patterns are variable).
The RIGHT coronary artery typically supplies:
SA node – 55% of people
AV node – 90% of people
Right atrium
Most of right ventricle
Part of left ventricle (diaphragmatic surface)
Interventricular septum – posterior third
The LEFT coronary artery typically supplies:
SA node – 45% of people
AV node – 10% of people
AV bundle
Left atrium
Most of left ventricle
Part of right ventricle
Interventricular septum – anterior 2 thirds
Coronary Artery Dominance
There are 3 criteria to determine coronary artery dominance; which artery supplies
1 AV node
2 Posterior Descending Artery
3 Posterior surface of the left ventricle
80% of the population are Right coronary artery dominant; 20% of the population are Left
coronary artery dominant or balanced
4. The common areas of referral of cardiac pain. Relate these to the segmental distribution of
the sensory nerve supply of the heart.
Cardiac nerve supply stems from T1-T5 (may extend down to T6-T7) and is bilaterally
innervated.
Cardiac pain is referred to skin supplied by spinal cord segments T1-T5; in particular:
 Inner aspect of the arms (innervated by T1)
 Skin of the Sternum (Ischaemic cardiac pain is typically referred to the
skin over the sternum in the midline: innervated by T2-T5)
5. External cardiac compression (noting the part of the sternum directly overlying the heart).
External cardiac compression is performed simultaneously with ventilatory support in
Cardiopulmonary Resuscitation CPR.
The lower third of the patient’s sternum, which overlies the ventricles, is depressed by direct
pressure from the heel of the operator’s hand (with added pressure from the other hand on
top). The operator uses a straight arm technique, rocking back and forth using body weight
rather than muscular effort to depress the sternum about 5 cms. At a rate of compressions per
minute.
6. The probable paths of emboli from an atrial thrombus.
RIGHT ATRIAL THROMBUS > embolus enters the right ventricle > enters the pulmonary
trunk > enters the R or L pulmonary arteries > gets stuck in the arterioles or capillary
beds.
LEFT ATRIAL THROMBUS > embolus enters the left ventricle > enters the aorta > can end
up anywhere in the systemic arterial system (places of severe complications include:
cerebral arteries, femoral arteries and coronary arteries