Wk One - Cardiac A&P, The Clinical Approach

Year 2 Clinical Approach

• Standard Pres > Gloves, Goggles, etc..

• Rapid assessment triangle - WOB, appearance and circulation to skin. (> SICK/NOT

• DRSABCDE (+AEIOUTIPS)

• METHANE if major, SITREP if not

• REST, REASSURANCE AND RAPPORT

• Brief history

• POETS + BGL

• AMPLE

• DOLORS

• VSS

• Secondary survey

• Treatment

• Transport & Refferal options

• HANDOVER - IMISTAMBO

AEIOUTIPS

What is the pathway blood travels in through the heart?

Deoxygenated blood enters through the SVC or IVC or coronary sinus into the right atrium, through the right atrioventricular valves to the ventricle, where it is then pushed up through the semilunar valves to the pulmonary arteries & trunk, where it will be oxygenated at the lungs. Oxygenated blood travels back to the heart through the pulmonary veins, and into the left atrium. This is pumped up through the mitral valve (bicuspid), to the left ventricle, and then through the semilunar valve to the aorta & systemic arteries. Whatever doesn’t make it out of the atrium, funnels back through the coronary arteries to provide O2 to the heart muscle.

What is the wall between the two ventricles called?

The muscular interventricular septum

Heart Anatomy

What is the fibrous skeleton of the heart?

Dense connective tissue rings that surround the valves of the heart and merge with the interventricular septum. It forms the point of insertion for cardiac muscle bundles and is where the valves attach to prevent stretching. Electrical insulator that prevents spread of action from the atrtai to the ventricles.

Bicuspid valve (/mitral/left atroventricular)

an aortic valve that contains only two cusps (or flaps) instead of three, controlled by the chordae tendinae & papilliary muscles. Prevents backflow into the atria.

Semilunar valve

Aortic & Pulmonic, consisting of three cusps or flaps which prevent the flow of blood back into the heart

%’s of blood in vessels

• 60% systemic veins and venules (blood reservoirs

• Systemic arteries and arterioles 15%

• Pulmonary vessels 12%

• Heart 8%

• Systemic capilliaries 5%

What does the circumflex artery supply blood to?

Posterolateral LV, sometimes inferior LV, may also supply posterior left bundle and A-V node.

What does the LAD artery supply blood to?

Anterior and anterolateral LV, 2/3 septum, medial anterior RV, lower 1/3 posterior RV

What does the RCA artery supply blood to?

Anterior RV, upper ½ (basal) posterior wall, posterior 1/3 septum, posterior left bundle, inferior LV, usually AV and proximal HIS bundle via AV nodal branch.

Where does the left coronary circulation originate from, and what pathway does this blood take?

Aortic root sinus - goes through left main (LM) and then the circumflex (Cx) and then the left anterior descending (LAD) and then diagnoal & septal (D & S)

Left main artery occulsion ECG sign

ST elevation in the AVR lead

Where does the right coronary circulation originate from, and what pathway does this blood take?

Aortic root sinus - through the right coronary artery (RCA) and then the Marginal (Mx) and then the Posterior Interventricular Artery (PIV) and then the SA (RCA 55 Cx 45) & AV nodes (Mx).

AV Node

Controls conduction, allows for ventricular filling "gatekeeper" between the atria and ventricles, ensuring coordinated heartbeats by introducing a slight delay in electrical impulses

SA node

the heart's natural pacemaker, a specialized cluster of cells in the upper wall of the right atrium that initiates electrical impulses, setting the heart's rhythm and rate (60-100)

Purkinje Fibers

electrical conduction and propagation of impulse to the ventricular muscle

Bundle of HIS

a specialized pathway of muscle fibers that transmits electrical signals from the atrioventricular node (AV node) to the ventricles, facilitating coordinated heart contractions

Time spent on heart contractions

Atrial systole - 0.1s, AV valve closes, Ventricular systole - 0.3s, all valves close, complete diastole - 0.4s

3 layers of a vein

Tunica intima/interna Endothelium (simple squamous) Elastic tissue In contact with the blood

Tunica media (thickest layer) Smooth muscle (innervated by SNS) Sheets of elastin

Tunica adventitia/externa Elastic and collagen fibres

Pressures in different vessels

• Aorta = 100mmHg

• Arteries = 100-40 mmHg

• Arterioles = 40-25 mmHg

• Capillaries = 25-12mmHg

• Venules = 12-8mmHg

• Veins = 10-5 mmHg

• Vena cave = 2mmHg

• R. Atrium = 0mmHg

Which ventricle is thicker?

Left

AV node

Acts as a gatekeeper between the atria & ventricles, and conducts between this + and backup pacemaker for the heart. (40-60)

Stupid acronyms for lymph flow

BHP - Blood hydrostatic pressure
IFHP - Interstitial fluid hydrostatic pressure
BCOP - blood colloid osmotic pressure
IFOP - interstitial fluid osmotic pressure
NFP - net filtration pressure

Where does excess interstitial fluid go?

To the cariovascular system and back into the blood plasma