pathophysiology of heart failure Flashcards
in systolic or diastolic dysfunction, is the ejection fraction reduced to less than 40% (the usual is 50-65%)?
systolic dysfunction
what are some conditions that cause a direct decrease in contractility in systolic dysfunction?
ischaemic heart disease
coronary artery disease
dilated cardiomyopathies
what are some valve dysfunctions that cause systolic dysfunction?
mitral and aortic regurgitation and aortic stenosis
what does systolic dysfunction ultimately result in?
increased end diastolic volume and pressure (increased preload)
ventricular dilation
decrease in cardiac output
what is the main problem in diastolic dysfunction?
impaired relaxation (decreased filling capacity)
what is a condition that reduces ventricular expansion?
restrictive pericarditis
what is a condition that causes increased heart wall thickness?
ventricular hypertrophy
pericardial tamponade can also cause diastolic dysfunction, what is pericardial tamponade?
build up of fluid in the pericardium restricting ventricular filling
in which side of heart failure does a ‘back up’ of blood cause oedema and ascites?
right sided heart failure
in which side of heart failure is there congestion of the GI tract causing weight loss and anorexia?
right side
which valve dysfunction causes prolonged right ventricular isovolaemic contraction in right sided heart failure? (2)
tricuspid regurgitation
pulmonary valve stenosis
which ventricular remodelling resulting from right sided heart failure canc cause left ventricular heart failure?
shift of intraventricular septum
in which side of heart failure is there decreased tissue perfusion and therefore signs of hypoxia and cyanosis?
left side
which sided heart failure is a cough with frothy sputum a sign of?
left sided heart failure (resulting from pulmonary congestion)
which side of heart failure is paroxysmal nocturnal dyspnea a sign of?
left side (pulmonary congestion and redistribution of fluid)
which valve stenosis can cause left sided heart failure?
mitral and aortic valve stenosis
what are the three compensatory mechanisms which try to compensate for heart failure but ultimately result in a worsening of the heart failure?
- frank starling mechanism
- sympathetic nerve activity
- renin-angiotensin-aldosterone system
how does the frank starling mechanism attempt to increase cardiac output?
by increasing preload and venous return and causing an increased dilation of the ventricles (ultimately this can result in dilated cardiomyopathies)
what problems does the frank starling mechanism cause in heart failure?
- decrease in actin/myosin overlap so decrease in tension generation
- increase in oxygen demand to generate this tension
- pulmonary congestion
what changes does increased sympathetic nerve activity result in?
increase in contractility and heart rate
why is increased vasoconstriction as a result of increased sympathetic nerve activity bad in heart failure?
decreases tissue perfusion (blood flow only to essential organs)
which compensatory mechanism does decreased tissue perfusion stimulate?
release of renin from the kidneys
this causes release of angiotensin
what does angiotensin 11 cause?
directly causes vasoconstriction
causes release of aldosterone which causes fluid and salt retention
what myocardial remodelling are angiotensin 11 and aldosterone involved in?
inflammatory responses leading to deposition of collagen and fibroblasts in the ventricles which leads to stiffness and a decrease in contractility
