Heart Failure Flashcards
What is the definition of Stroke Volume?
The volume of blood pushed out in one contraction
What is the definition of Ejection Fraction?
The proportion of end diastolic volume pumped into the aorta of the heart
Normal EF is 55-70%
What is the definition of Cardiac Output?
Amount of blood pumped out of the heart in 1min
HRxSV=CO
What is Frank Starlings Law?
The relationship between stroke volume and end diastolic volume.
What is preload?
The amount of ventricular stretch at the end of diastole ( the amount the muscle fibres stretch before systole)
also called left ventricular end diastolic pressure
What is afterload?
The pressure needed to be overcome in order to eject blood during systole.
Its affected by the mean arterial pressure (MAP ie HTN) If there is increased resistance in the aorta then after load will be bigger.
What happens in systole of the cardiac cycle?
Isovolumetric contraction (the ventricles contract and blood is pushed out) Systolic ejection
What happens in diastole in the cardiac cycle?
Isovolumetric relaxation
Ventricular filling
What are some causes of HF?
Coronary heart disease
Diabetes
HTN
What happens in HF?
The heart is unable to meet the demands the body.
the ventricle do not function as well so there is a decreased cardiac output leading to poor systemic perfusion (forward failure) and venous pooling/congestion (backward failure)
What happens in systolic HF?
There is a decrease in stroke volume and ejection fraction.
Causes of this include diabetes, MI, valvular heart disease, arrhythmias, dilated cardiomyopathy, myocarditis
What happens in diastolic HF?
There is a decrease in stroke volume but the ejection fraction is preserved. Causes of this include diabetes, MI, valvular heart disease, hypertrophic cardiomyopathy, constrictive pericarditis, pericardial tamponade
What is BNP?
Brain natriuretic peptide
It is a hormone released in response to increased ventricular filling and stretching.
It is mainly produced in the left ventricle myocardium in response to strain.
high levels of BNP is associated with a poor prognosis.
What symptoms would you expects in Right HF (backward failure)?
Peripheral oedema
hepatosplenomegaly- hepatic venous congestion–> ascites and jaundice
increased JVP
What symptoms would you expect in Left HF (forward failure)?
pulmonary oedema decreased exercise tolerance dyspnoea orthopnoea Paroxysmal nocturnal dyspnoea Cardiac wheeze.
What is NYHA Class 1?
No symptoms or exercise limitation
What is NYHA Class 2?
Mild symptoms and limitation to exercise
What is NYHA Class 3?
moderate symptoms and marked limitation to exercise
What is NYHA Class 4?
Severe symptoms even at rest and unable to carry out any activity without discomfort.
on inspection the patient looks unwell (pale and grey)
they have cold and clammy peripheries with ?cyanosis
their sputum is frothy and blood stained
they are orthopnoeic using accessory muscles
they may also have a cardiac wheeze
Dr what is your diagnosis?
acute left ventricular failure
what are some signs of acute left ventricular heart failure?
sinus tachycardia or AF
systolic hypotension
signs of cardiomegaly (displaced apex beat, signs of valve disease)
third and fourth heart sounds
right sided or bilateral pleural effusions
What radiographic changes would you expect in acute left ventricular failure?
cardiomegaly upper lobe diversion diffuse mottling of lung fields prominent hilar shadows (bat wings) small pleural effusions fluid in fissures
what investigations would you order in suspected acute left ventricular failure?
Echo within 48hrs for evidence of reduced LV ejection fraction and valvular disease
Bloods: FBC, U+Es, blood glucose, BNP (single raised measurement confirms diagnosis), troponin
ABG- for evidence og hypoxaemia and acute respiratory distress
ECG- any evidence of arrhythmia, heart block, ischaemia, ventricular hypertrophy
what are some causes of acute left ventricular failure? (do you know a mnemonic?)
Coronary syndrome Hypertensive emergency Arrhythmia Mechanical e.g. acute valve leak, VSD, LV aneurysm Pulmonary embolism
