Cardiac Flashcards
(40 cards)
Heart failure =
Heart cannot pump blood to body at rate that is needed
coronary veins drain into…
right atrium via coronary sinus
heart function =
filling (diastole)
pumping (systole)
Systole determines…
cardiac output
Cardiac output =
stroke volume x HR
cardiomyopathy =
cardiac muscle abnormality (enlarged, thickened or stiff) - reduce effectiveness of heart - lead to HF
Dilated cardiomyopathy
dilated ventricles
less blood pumped from heart as ventricles are dilated and weakened
can lead to systolic HF (decrease in ejection fraction)
caused by excessive alcohol, pregnancy, genetic
Hypertrophic cardiomyopathy
ventricular hypertrophy
thick ventricles = small chamber = prevents proper filling
less blood pumped from heart because ventricles cannot fully relax
can lead to diastolic HF (doesn’t influence ejection fraction)
Caused by mutations in genes encoding sarcomeric proteins = myocardial disarray
Restrictive cardiomyopathy
stiff heart muscles = diastolic problems = dilated atria
LV maintains normal dimensions but left atrial hypertrophy and dilation
back flow of blood from LA to pulmonary system
this leads to right ventricular hypertrophy
e.g. cardiac amyloidosis
myxoma
cardiac tumour
Arryhthmogenic right ventricle cardiomyopathy
effects right ventricle (can effect left)
mutation in desmosome
Mutations that cause desmosomal abnormality = causes fibrofatty replacement of RV muscle
Brugada syndrome is caused by
Sodium ion channel abnormality in RV epicardium
Causes of Left Ventricular Hypertrophy…
Hypertension
Aortic stenosis
Coarctation of the aorta
Cardiomyopathies
Causes of Right Ventricular Hypertrophy …
Chronic obstructive pulmonary disease
Idiopathic pulmonary hypertension
Pulmonary stenosis
Complex congenital heart disease
Syncope =
reversible LOC due to inadequate blood flow to the brain
fast onset
short duration
spontaneous recovery
Non-cardiac cause of syncope =
Reflex - vasovagal or carotid sinus syndrome (usually a prodrome - sweating, nausea, pallor = patient feels like they will pass out so try to hold on to something)
Neural - situational (follows a specifc trigger like coughing)
Orthostatic hypotension - autonomic failure or volume depletion (haemorrhage, vomiting) - patient may feel dizzy when changing position
Non- cardiac cause of LOC =
epilepsy, stroke, pulmonary embolus, hypoglycaemia
Cardiac causes of syncope =
arrhythmia - Brady/tachy
aortic stenosis
HCM
prosthetic valve dysfunction
MI
acute aortic dissection
How to know if syncope is cardiac?
no prodome = no warning/trigger
patient just drops
may hear heart murmur
ECG/ ambulatory monitor (?pauses, HB, arrhythmia)
echo might show structural abnormality
cardiac output (systole) is influenced by…
contractility of myocardium
preload (amount of blood filling ventricles before systole)
afterload applied to ventricles (what ventricles have to overcome to push blood out of heart)
heart rate
HF early adaptations
reduced stroke volume + decreased cardiac output
increased amount of blood left in ventricles in diastole (increased end diastolic volume)
= muscle fibres in ventricles lengthen + tighten more to promote more forceful contraction to eject excess blood (frank-starling law)
increased end diastolic volume = increased contractility = increased cardiac output
Reduced cardiac outpatient is also picked up by baroreceptors = activation of sympathetic nervous system = stimulation of increased myocardial contractility = increased cardiac output , increased HR, increased venous retention
HF chronic adaptations
sympathetic activation causes ventricular remodelling + dysfunction
reduced cardiac output also causes decreased renal blood flow = activated renin-angiotensin-aldosterone system = further contributes to cardiac remodelling + dysfunction
eventually chronic adaptations cause increased pressure in ventricles = increased pressure in atria = pulmonary congestion + peripheral oedema
right sided HF symptoms
congestion of peripheral tissue
increased mutual venous pressure
pitting Lower leg oedema
liver congestion
left sided HF symptoms
reduced cardiac output = pre syncope, fatigue, SOB on exertion, orthopnea,
pulmonary congestion = SOB, cough, course crackles, hypoxia
excessive pulmonary congestion = pulmonary hypertension = right sided HF
