Cardiac Flashcards
Where is the aortic valve located
Outflow tract from left ventricle, start of the aorta
Where is the pulmonary valve located
Outflow tract from right ventricle, start of pulmonary artery
Where is the tricuspid valve located
Between right atrium and right ventricle
Where is the mitral valve located
Between left aria and left ventricle
Where do the coronary arteries originate
Aortic sinus, just above aortic valve
Where does the RCA anatomically run
RCA runs along coronary sulcus - groove between atria and ventricles
What does the RCA supple
Inferior part of the heart and if right dominant (70-80%) posterior descending artery
SA & AV node
Describe how the PDA is supplied per dominance (%)
70-80% right dominant (RCA)
5-10% left dominant (circumflex)
10-20% co-dominant (RCA & circumflex)
How are the coronary arteries supplied
During myocardial contraction the coronary arteries and squeezed, therefore 85% perfusion during diastole
Describe coronary veins landmarks and end points
Coronary veins run parallel to arteries and terminate into the back of the heart via the coronary sinus into the right atrium
Describe phases (4,0,1,2,3) of the cardiac action potential
- Diastole- (-90mv)
0.Depolarisation- (Na+ channels open, close at 20mv but overshoots to 50mv) - Temp repolarisation- open K+
- Plateau phase- balance to prevent irregular rate / arrhythmias
- Rapid repolarisation
Frank starling law
Force depends on the extent to which fibres are stretched (can be overstretched reduces contractility)
Cardiac output equation
MAP equation
CO = SV x HR
MAP = CO x SVR
Short term regulation of BP
Baroreceptors
Long term management of BP
Kidney control via hormones:
Renin angiotensin aldosterone system
Describe Hormone control of BP
Reduced renal flow = renin > angiotensinogen > angiotensin 1 > angiotensin 2
Angiotensin 2 = vasoconstriction
Also increased aldosterone > sodium retention > increase blood volume
Describe vasopressin
From pituitary gland:
Enhances water retention & blood volume
Causes vasoconstriction
4 types of shock and examples of each
Hypovolaemic - haemorrhaging or non-haemorrhagic (burns/GI)
Distributive - anaphylaxis, sepsis
Cardiogenic - MI, myocarditis, arrhythmia
Obstructive- PE, Tamponade, tension P
Effects of blood loss (%)
<10% minimal effect
10-20% loss not usually life threatening
>30% severe symptoms
Average amount of blood /kg in adult
70ml/kg
Benefits of arterial line
Accurate best to beat BP measurements
Frequent gas measurements
Complications of arterial line insertion
Haematoma, infection, embolus, ischemia, pain, blood loss
Describe over and under damped arterial line trace
Underdamped - sharp edges, from hard lines
Under damped - clot, air bubble, link in tube
MAP the same in both
CVP lines…
Recorded at right atrium
Reflects filling of atrium
Normal 0-6 mmhg
Check waveform before use
Varies with breathing - measured at end of expiration
DESCRIBE TRACE
Benefits of focused echo
Volume status
Contractility
Effusion / tamponade
Signs of tamponade (becks triad)
Raised JVP
Muffled heart sounds
Hypotension
Causes of high CVP
RV failure
Tricuspid regurgitation
Pericardial effusion
High peep
Tension pneumothorax
Define shock
Imbalance between oxygen demand and supply
Poor tissue perfusion
Sepsis recognition and initial treatment
News score
Signs of infection
Bloods (WCC <4 or >12)
Cultures, oxygen, ABG, volume, ABx, urine catheter, manage MAP
