CVS 238 Heart Failure Flashcards
(44 cards)
What can you split heart failure into?
Right and left sided
What are the features of right sided heart failure?
congestion of peripheral tissues –> oedema, ascites, hepatomegaly
What are the features of left sided heart failure?
decreased CO and pulmonary congestion orthopnoea, PND, frothy sputum and cough activity intolerances, cyanosis, hypoxia
What can left sided heart failure be split into further?
Systolic and diastolic Systolic: insufficient contraction diastolic: insufficient relaxation
What are some causes of systolic dysfunction?
Impaired contractility: ischaemia Increased afterload: aortic stenosis/HTN
What is the cause of diastolic dysfunction?
impaired filling: hypertrophy, cardiomyopathy, pericardial disease
What are the mechanisms of HF?
cardiac muscle necrosis or apoptosis
poor contractility: gene expression changes, changed energy metabolism, changes in calcium handling
How can changes in calcium handling result in HF?
depleted stores in the sarcoplasmic reticulum = less release and th. energy to contract = systolic dysfunction impaired reuptake of calcium = diastolic dysfunction
What are the two main mechanisms of compensation in HF?
Frank-Starlings law and neurohumoral activation
How does compensation in heart failure work?
vasoconstriction to increase TPR venoconstriction to increase CVP and preload increased circulating catecholamines increase RAAS activity to increase blood volume = restoration of CO at the expense of higher filling pressures
What are the two reasons and the type types of ventricular hypertrophy and remodelling in HF?
Pressure overload = concentric hypetrophy = diastolic dysfunction Volume overload = eccentric hypertrophy = vicious circle/exacerbation of HF
What is concentric hypetrophy?
Increase in number of muscle fibres
What is eccentric hypetrophy?
Increase in length of muscle fibres
Why is compensation in HF not good in the long term?
It results in a faster deterioration of the muscle to pump against the increased TPR Cardiomegaly from increased filling pressures and oedema from volume expansion
What are the problems as a result of cardiomegaly in HF?
Heart has to work harder to generate pressures and enlarged ventricles but valves stay the same- leaky valves
What are ventricular arrhythmias due to in HF?
delayed after depolarisations - reentrance circuits in the heart resulting in abnormal release of calcium and a depolarisation after AP
What are the principles of treatment for HF?
Decrease cardiac oxygen demand th. work via arterial and veno dilation
decrease stroke volume –> arterial pressures
decreased cardiac dilatation and oedema
decrease arrhythmias
increase coronary perfusion
increase contractility
What drugs will decrease cardiac oxygen demand & increase stroke volume
ACEI by decreasing arterial pressures - vasodilators
What drugs are useful in oedema?
diuretics
What drugs increase coronary perfusion and decrease arrhythmias?
beta blockers
What drug increases heart contractility?
digoxin
What conditions might mimic heart failure?
High output circulatory states: sepsis, anaemia, liver failure, beri-beri, thyrotoxicosis, pagets
What is BNP?
brain natriuretic peptide - rises in response to myocardial wall stress. high levels in hf despite optimal treatment has a poor prognosis
What are the general non-pharmacological managements in HF?
monitor weight gain salt-restricted diet limited alcohol intake moderate daily exercise fluid restriction in severe HF
