Cardio Flashcards
Stroke volume =
End diastolic - End systolic (LV)
Ejection fraction =
Stroke volume / End diastolic
P wave refers to
atrial depolarisation
P-Q signifies what
Delay between SA and AV node
QRS represents
Ventricular depolarisation
R =
ventricular depolarisation
S -T
Full ventricular depolarisation
T =
Ventricular repolarisation
Raised T waves?
Hyperkalaemia
ST elevation?
MI
No p waves in what?
AF
Systolic ejection murmur?
Aortic stenosis
Cardiac output
stroke volume X heart rate
Cardiac reserve reduced to what by unreliable atria?
13l
Normal cardiac reserve
15l
Blood pressure is?
Cardiac output X systemic vascular resistance
Main source of energy for the heart?
Fatty acids
When calcium binds to the troponin what happens?
Tropomyosin complex forms and moves exposing myosin binding sites.
What does TIBE stand for?
Tachy inspire, Brady expire
Main pacemaker of the heart?
SA node
Secondary pacemaker
AV node
backup pacemakers?
Cardiomyoctes
What happens in the membarane potential?
Na+ open, Na+ closed,
Ca2+ open, fast K+ close,
Ca2+ close Slow K+ open
- resting
What happens at stage 0 of resting membrane?
Na+ open
What happens at stage 3 of membrane potential?
Ca2+ close Slow K+ open
What happens at stage 2 of membrane potential?
Ca2+ open Fast K+ close
Stage 1 of membrane potential?
Na+ close
What is active hyperaemia?
Active flow of blood to areas with high metabolic demand
What is the frank starling mechanism?
Greater preload increases the output to a sweet spot ;)
Left shift of frank starling curve?
Exercise and pharmacological stimulation
Right shift in frank starling curve?
Myocardial loss and pharmacological depression
Sympathetic stimulation does what (adrenaline noradrenaline)
Stimulates cAMP more Ca2+ enters cell, greater cross bridge linking, starling curve moves to the left .
Bowditch effect is what?
HR increases cardiac performance to a point
What increases preload?
Higher circulating volume, aortic pressure, lower heart rate due to diastole = longer, high CVP, and lower venous compliance.
What is starlings law?
Longer muscle fibre length = increased contraction
What is inotropy?
Contractibility
What is lusitropy?
Relaxation
Chronotropy?
Heart rate (SA node)
Dromotropy?
Conduction through AV node
Left shift in frank starling increases what?
Pre-load
What does NO do?
Relaxation of endothelial cells
normal ejection fraction?
50-75%
Ejection fraction during exercise?
90%