heart failure Flashcards
what is it
any disorder that impairs the ability of the heart to function as a pump
what is most common cause of heart failure in western countries
coronary artery disease
causes
- ischaemic heart disease
- cardiomyopathy
- hypertension
- valvular heart disease
- alcohol and drugs
- right heart failure
- arrhythmias
- infections
factors involved
- venous return
- outflow resistance
- contractility of the myocardium
- salt and water retention
what does heart failure to do blood volume
reduces volume of blood ejected with each heart beat
what does the increased diastolic volume do
stretches the myocardial fibres
what is reduced early in heart failure
the ejection fraction
how is cardiac output maintained during heart failure
sinus tachycardia
what symptoms does increased venous pressure contribute to
- dyspnoea
- accumulation of interstitial fluid
- ascites
what is outflow resistance
the load or resistance against which the ventricle contracts
what is outflow resistance formed by
- pulmonary and systemic resistance
- characteristics of the vessel walls
- volume of blood that is ejected
what does an increase in afterload do to cardiac output
decrease it
what autonomic innervation is activated during heart failure
sympathetic
what do myocardial depressants do
decrease myocardial contractility
what does excitation of myocyte membrane cause
rapid entry of calcium into myocytes from the extracellular space
how is relaxation of heart mediated
by uptake and storage of calcium by sarcoplasmic reticulum
what is apoptosis
programmed cell death
is apoptosis associated with heart failure
yes
where is atrial natriuretic peptide released from
atrial myocytes
when is ANP released
in response to stretch.
what does ANP induce
- vasodilatation
- suppresses RAAS
can BNP levels be used for heart failure
yes
where is brain natriuretic peptide secreted by
ventricles
what does pro-BNP release
BNP.