cardiac function Flashcards
describe HFpEF and the mechanism
is diastolic
- normal ejection fraction >40%
- mechanism = stiffening ventricles giving impaired relaxation
describe the remodelling associated with HFpEF
- concentric (myocytes in parallel)
- increased wall thickness
causes and symptoms of HFpEF
- hypertension
- aortic stenosis
symptoms usually w/ exercise
factors associated with HFpEF
- older
- female
- diabetes
- AF
- CKD
describe HPrEF and the mechanism
systolic
- reduced <40%
- mechanism = reduced force of contraction
describe the remodelling associated with HFrEF
- eccentric (myocytes in series)
- reduced wall thickness
causes of HFrEF
- MI
- IHD
- valve regurgitation
how do you calculate pulse pressure
= systolic pressure - diastolic P
how do you calculate MAP
= Pd + 1/3(Ps - Pd)
what does a large pulse pressure mean
normal resting = 40 mmHg
large because arteries have reduced compliance therefore are stiff
treatment for mitral valve stenosis patients
- percutaneous mitral valvuloplasty
- mitral valve replacement surgery
how can mitral stenosis cause atrial arrhythmias
autonomic nervous system remodeled, changing electrical properties
atria dilate → increases re-entrant path lengths & promotes AF
↑ atrial P → stimulates stretch-activated channels
atrial fibrosis → regional slowing of conduction
describe the ‘natural’ course of atrial fibrillation
- paroxysmal AF = comes and goes
- persistent AF = stays for longer
- permanent AF = cant be controlled by shock or drugs
is a progression, the more you have it, the more it will come back and change the characteristics of the tissue
what treatments are possible for AF
Rhythm control
- amiodarone
- sotalol (B-blocker)
Rate control
- Ca channel blocker
- B-blocker
- digoxin
also an anticoagulant e.g. warfarin
explain a systolic murmur and where it is best heard
increased velocity through narrow aortic valve during ejection, this leads to turbulence (reynolds number) and is heard as a murmur
this systolic ejection murmur is heard loudest at the upper right sternal border and radiates to the neck bilaterally (best with diaphragm)
why do you get a splitting in the second heart sound and what does it mean if you can’t hear this in a patient with aortic stenosis
splitting because pulmonary valve shuts slighter after the aortic valve.
- aortic component of second heart sound tends to decrease and become softer when aortic stenosis becomes more severe. This is due to increased calcification preventing the valve from ‘snapping’ shut and producing a sharp, loud sound
why might you see a larger QRS in a patient with aortic stenosis
- patient has LV hypertrophy (high afterload on LV) therefore more conduction pathways so faster activation
explain chest discomfort during exercise in a patient with aortic stenosis
- angina
- increased HR and ventricular wall tension (demand)
- cannot be met by increased coronary perfusion (supply) due to stenosis
demand > supply during exercise
treatment possibilities for aortic stenosis
- medical therapies dont stop progression but are useful for symptoms
- aortic valve replacement
(development of angina, syncope, or dyspnoea are signs for replacement)
describe a doppler echocardiography
- see the velocity of BF through the heart
- work out pressure gradient across valves
- work out the valve area
