Cardiac cycle Flashcards
Left ventricle
thick-walled and circular
generates greater pressures
prominent papillary muscles seen in LV which anchor the mitral valve leaflets
right ventricle
thin-walled and crescentic lower pressures
what does raised pulmonary artery wedge pressure indicate?
vasoconstriction fluid overloaded right to left shunt VSD left ventricular failure mitral valve failure pulmonary hypertension
what does decreased pulmonary artery wedge pressure indicate?
vasodilation
hypovolaemia
right atrial pressure
is equivalent to the central venous pressure and jugular venous pulse
central venous pressure waveform
a wave c wave x descent v wave y descent
a wave
atrial contraction
c wave
tricuspid valve bulging back into RA
x descent
atrial relaxation
v wave
atrial filling with closed tricuspid valve
y descent
atria empties into ventricle
what is an arterial line used for?
measure pressure
no blood in the line
what is the dicrotic notch?
when the aortic valve closes
what is isovolumetric contraction?
occurs in early systole during which the ventricles contract with no corresponding volume change
what is isovolumetric relaxation?
beginning of diastole
perfusion of heart
rise in LV pressure during systole acts to occlude coronary vessels running through it so most perfusion occurs in diastole
what causes coronary vasoconstriction?
increases pp O2 decreased pp CO2 - alkalosis alpha 1 stimulation ADH Angiotensin Thromboxane
what causes coronary vasodilation?
decreased ppO2 increased ppCO2 - acidosis lactate adenosine beta 2 stimulation prostacyclin
heart sounds
2 major sounds
due to valve closure
s1 = represents closure of mitral and tricuspid valves
s2 = represents closure of aortic and pulmonary valves
left sided valves normally close fractionally ahead of the right.
heart murmurs
usually associated with heart pathology
blood flow normally laminar but when there is turbulent flow it produces abnormal sound due to vibrations in the surrounding structures
what are the types of valvular murmurs?
stenotic valve
regurgitant/ incompetent valve
stenotic valve
stiff or narrowed valve that doesn’t open completely
blood forced through narrowed opening - ejection murmur
regurgitant/ incompetent valve
valve edges are scarred - don’t close completely so there is some backflow of blood
what could non-valvular murmurs be a sign of?
pregnancy
ASD
VSD
PDA
what is ASD?
atrial septal defect
what is VSD?
ventricular septal defect
what is PDA?
patent ductus arteriosus
when do stenotic mitral and tricuspid valve murmurs occur?
diastole
when do incompetent mitral and tricuspid valve murmurs occur?
systole
when do stenotic aortic and pulmonary valve murmurs occur?
systole
when do stenotic aortic and pulmonary valve murmurs occur?
diastole
murmur in aortic stenosis
systolic crescendo-diminuendo with radiation to carotids
clinical presentation of aortic stenosis
dyspnoea
fainting/ syncope
chest pain
palpitations
treatment for aortic stenosis
catheterisation
valve replacement
when do the waves on the ECG happen?
just before pressure changes
what is the ideal resting cardiac output?
5L/min
emptying of ventricles
ventricles are not completely emptied during ventricular systole
what is an indication of valve stenosis?
significant difference between highest pressure in ventricles and aorta
mechanical valves
last 20 years
require anticoagulants for life
very expensive
given to younger people
tissue valves
last 10 years
given to older people
cheaper
