Heart Failure Flashcards
Heart failure as a result of excessive haemodynamic burden is another low cardiac output state, what does it involve?
this time involving a relative (not an absolute) failure of contractility to pump sufficient blood to perfuse the tissues in the face of a disruption or obstruction to output
Name the 4 topics of heart failure
Systolic dysfunction
Diastolic dysfunction
Excessive haemodynamic burden
Unrealistic peripheral demand for tissue perfusion
What is cardiac output?
The product of heart rate (HR) and stroke volume (SV) (i.e., the volume of blood pumped per beat), which is itself dependent on force of contraction. So in mathematical terms, CO=HR*SV
what is the likely cause of “Heart failure as a result of excessive haemodynamic burden”?
This can be related to abnormal blood movement or flow (as in valvular disease or heart problems such as septal defects present at birth) or abnormally high blood pressure.
in “Heart failure as a result of excessive haemodynamic burden”
what causes stroke volume and corresponding cardiac output (i.e. leads to left heart failure).
Arterial hypertension provides an increased burden (or afterload) related to increased total peripheral (or systemic vascular) resistance on the left ventricle, which limits how much blood can be pumped into the aorta against this higher pressure
– and which in turn reduces stroke volume and corresponding cardiac output (i.e. leads to left heart failure).
what account for the majority of heart failure disease cases in the western world?
arterial hypertension along with ischaemic heart disease-related systolic dysfunction
What is the Frank Starling mechanism?
Cardiac stretch (related to preload and caused by blood returning (venous return) to the ventricles during diastole, i.e. end diastolic volume) is related to the force of contraction and thereby stroke volume,
what is heart failure due to “Unrealistic peripheral demand for cardiac output” related to?
decreased oxygen-carrying capacity of blood, e.g.severe anaemia
excessive metabolic demand for tissue perfusion, e.g. thyrotoxicosis
maintenance of blood pressure in face of severe hypotension, e.g.
severe infection/sepsis, anaphylaxis (involves peripheral vasodilation/fall in total peripheral resistance)
and
hypovolaemic circulatory shock
How is Systolic dysfunction defined?
Absolute failure of contractility
Low cardiac output state
How is Diastolic dysfunction defined?
Ventricular diastolic filling failure
Low cardiac output state
Increased ventricular stiffness (reduced compliance)
what leads to a state of right heart failure secondary to lung disease known as cor pulmonale.?
pulmonary hypertension has the same effect on stroke volume involving the right ventricle, leading to a state of right heart failure secondary to lung disease known as cor pulmonale.
these terms:
Relative failure of contractility and Low cardiac output state.
are synonymous to what?
Excessive haemodynamic burden
which diseases are related to “heart failure due to Excessive haemodynamic burden”
valvular disease
congenital heart defects
increased total peripheral resistance
arterial hypertension (= left heart failure)
increased pulmonary resistance (associated with lung disease)
pulmonary hypertension (= right heart failure “cor pulmonale”)
what is heart failure due to “Unrealistic peripheral demand for cardiac output” related to?
decreased oxygen-carrying capacity of blood, e.g.severe anaemia
excessive metabolic demand for tissue perfusion, e.g. thyrotoxicosis
maintenance of blood pressure in face of severe hypotension, e.g.
severe infection/sepsis, anaphylaxis (involves peripheral vasodilation/fall in total peripheral resistance)
and
hypovolaemic circulatory shock
explain what happens during heart failure due to “Unrealistic peripheral demand for cardiac output”
the heart fails to either maintain an unreasonable required level of tissue perfusion
or sustain sufficient arterial blood pressure for tissue perfusion in the face of severe hypotension, associated with e.g. septic or anaphylactic shock and other types of circulatory failure, such as hypovolaemic shock.
in heart failure due to “Unrealistic peripheral demand for cardiac output”
why does the heart fail to maintain an unreasonable required level of tissue perfusion?
that is due to limited blood oxygen-carrying capacity as in severe anaemia or excessive metabolic demand as in the hypermetabolic state of thyrotoxicosis;
what is blood pressure a result of?
blood pressure (BP) is the product of cardiac output (CO) and total peripheral resistance (TPR), i.e. BP=CO*TPR.
__________ causes causes a relative failure of cardiac contractility, as the heart (although still failing) is functioning normally and responding to what is an impossible challenge
unrealistic demand for cardiac output
what are the main symptoms of heart failure?
Breathlessness (during activity or at rest; may be worse when lying down, e.g. at night)
Fatigue (tired most of the time) and exercise intolerance
Swollen ankles (due to oedema)
what are the less common symptoms of heart failure?
Persistent cough (worse at night)
Wheezing
Bloating around abdomen (peritoneal fluid accumulation or ascites)
Loss of appetite
Weight change
Confusion
Dizziness and fainting
Tachycardia
Pounding, fluttering or irregular heart beat (palpitations)
_________ are related to pulmonary congestion, fluid accumulation/oedema and pleural effusion stemming from a rise in pulmonary venous pressure (linked to failure of the left heart). Swollen ankles (as well as feet and legs) reflect peripheral oedema owing to fluid retention, venous circulatory congestion and a rise in central venous pressure (linked to failure of the right heart).
Respiratory problems
___________ is the result of a more general, compensatory sympathetic autonomic nervous system discharge (also linked with cold, pallid skin in respect of peripheral vasoconstriction), aimed at raising cardiac output in order to support blood pressure for tissue perfusion.
Tachycardia
Feeling tired most of the time reflects ____________
a lack of blood supply to working (skeletal) muscle
__________ could potentially lead to multiple organ failure
general lack of tissue perfusion
