Week Four - Case One Flashcards
what is heart failure typically defined as;
the inability of the heart to pump adequate amounts of blood to meet the body’s metabolic demands
what is the classic presentation of heart failure
shortness of breath (especially on exertion and on lying flat), fatigue and ankle oedema
what are the classic signs of heart failure
Signs may include hepatomegaly, tachycardia, tachypnoea and raised JVP.
what are the two broad groups heart failure can sometimes be divided into
those with a normal ejection fraction (>50%), and those with a reduced ejection fraction (<50%), however, the management is similar
There is a correlation between ejection fraction and prognosis – the lower the ejection fraction, the worse the prognosis
what is the mainstay drug of treatment that has been shown to improve survival
ACE inhibitors
what is systolic HF
Systolic HF – inability of the heart to contract efficiently to eject adequate volumes of blood to meet the body metabolic demand [most common].
what is diastolic HF
Diastolic HF – reduction in the heart compliance resulting in compromised ventricular filling and therefore ejection [pericardial disease, restrictive cardiomyopathy, tamponade]. Increasingly recognised as an important cause of heart failure – it is often present in elderly patients with a normal CXR and otherwise unexplained SOBOE (shortness of breath on exertion)w
what is left HF
Left HF – inability of the left ventricle to pump adequate amount of blood leading to pulmonary circulation congestions and pulmonary edema. Usually results in RHF due to pulmonary hypertension. Defined as an ejection fraction of <40%.
what is right HF
Right HF – inability of the right ventricle to pump adequate amount of blood leading to systemic venous congestion, therefore peripheral edema and hepatic congestion and tenderness.
Most commonly the result of respiratory disease – especially COPD
The presence of raised JVP and peripheral oedema are suggestive of right HF in particular
what is congestive HF
failure of both the right and left ventricles, which is common
what is low-output HF
heart failure resulting from reduced cardiac output [most common type] – also referred to as HFrEF – Heart Failure reduced Ejection Fractions
what is high-output HF
High-output HF – heart failure that occurs in normal or high cardiac output due to metabolic demand and supply mismatch, either due to reduced blood oxygen carrying capacity [anaemia] or increase body metabolic demand [thyrotoxicosis] – also referred to as HFpEF – Heart Failure preserved Ejection Fraction
what is acute HF
acute onset of symptom presentation often, but not always due to an acute event [MI, persistent arrhythmia, Mechanical event (ruptured valve, ventricular aneurysm)]
Often an acute presentation to hospital
May be the first presentation, or may be “acute on chronic”
what is chronic HF
– slow symptoms presentation usually due to slow progressive underlying disease [CAD, HTN]
Typically a GP based diagnosis
what is acute-on-chronic HF
Acute-on-chronic – acute deterioration of a chronic condition, usually following an acute event [anaemia, infections, arrhythmias, MI
how many people does HF affect in the uK
920,000 people - about 1 in 70
what is the average age of diagnosis of HF
77
what are the ischaemic heart disease causes of HF
- myocardial ischaemia
- myocardial infarction
- in IHD infarction causes impaired ventricular function, therefore reduced contractility function and HF. IHD is the most common cause of HF along with HTN
how does hypertension cause HF
increases strain on the heart, since the heart has to pump blood against a high after load, leading to hypertrophy which increase the chances of arrhythmias.
the heart eventually gets too big for the coronary system to perfuse leading to IHD and compromised ventricular function
what valvular diseases lead to HF
Mitral Regurgitation [volume overload]
Aortic stenosis [Pressure overload] – particularly chronic excessive afterload
Tricuspid Regurgitation [volume overload]
VSD/ASD [volume overload] – excessive preload
what pericardial diseases lead to HF
pericarditis
pericardial effusion
what drugs are the most common cause of HF
- chemotherapeutic drugs; beta-blockers are the most common cause, but calcium channel blockers and ant-arrhythmatics are also implicated
- alcohol; acute heart failure, arrhythmias such as AF and dilated cardiomyopathy are more common in alcoholics. Alcohol also increases the risk of infection – infection can worsen chronic heart failure due to toxic effects of infection on heart itself along with vasodilation and tachycardia increase myocardial oxygen demand
- cocaine
how can thyrotoxicosis/myxedema cause heart failure
can cause HF due to direct effets on myocardium, bradycardia and peridcardial disease
how does bradycardia induce HF
Bradycardia – CO = HR X SV. Therefore reduced HR reduces CO
how does tachycardia induce HF
Tachycardia –Reduced ventricular filling duration, increased heart oxygen demand and ventricular dilatation
how does abnormal artial and ventricular contractions induce HF
Abnormal atrial and ventricular contractions – AF removes active ventricular filling leading to reduced EDV and CO. VT also causes reduced EDV due to reduced ventricular filling period.
what is congestive cardiomyopathy
weakening and dilation of ventricular walls leading to overstretching, therefore reduced contractile efficiency. most common cause of HF in the absence if IHD, valvular disease and HTN.
what is hypertrophic cardiomyopathy
thickening of the heart muscle wall leading to reduced compliance and therefore reduced CO. the thickening involves an increase in fibrous tissue of the heart, which increases the chances of arrhythmias such as ventricular fibrillation
which disease has strong familial links
hypertrophic cardiomyopathy
what is the most common cause of death in young adults
ventricular fibrillation
what is restrictive cardiomyopathy
reduced heart compliance without significant increase in muscle wall thickness leading to reduced EDV and CO. this can be caused by infiltrative disease such as sarcoidosis, amyloidosis, haemachromotosis and endocardial fibrosis
what is MAP
CO X TPR
what is CO
SV x HR
what is SV
EDV - ESV
what does MAP stand for
mean arterial pressure
what does HF cause a drop in
heart failure causes a drop in the mean arterial pressure that initially stimulates baroreceptors that feed back into the medullary cardiovascular centre
what does this centre then try to do
tries to increase and maintain the mean arterial pressure
how does the MCVC try to increase and maintain the MAP
by reducing vagal tone and increase sympathetic tone leading to increase heart contractility and rate therefore output
what does the sympathetic system also do
also increases the contraction of arteries (increasing TPR) and veins (increasing venous return) and the release of adrenaline from the adrenal medulla
what other system is stimulated in HF and why
the RAS system is also stimulated due to reduced kidney perfusion caused by reduced MAP and vasoconstriction and direct sympathetic stimulations
what does angiotensin II cause
vasoconstriction, aldosterone release and ADH release causing sodium and water retention by the kidneys
why are these mechanisms beneficial initially
because they increase blood volume, therefore venous return and SV, TPR, and HR - leading to a high maintained CO
how does increased TPR lead to a worse situation
increased after load therefore increasing workload and strain on the heart
tissue undwrperfusion leading to ischaemia
RAS system stimulation
how does increased HR lead to a worse situation
increased world and therefore oxygen demand of the heart
how does fluid retention lead to a worse situation
increase stretching of the heart eventually leading to dilation of ventricles which possess reduced contractility
fluid build up causes fluid transudation into interstitial tissue causing peripheral and pulmonary oedema
what does fluid retention cause
hyponatremia and hypokalaemia
what are the symptoms of HF
- dyspnea
especially on exertion and is due to pulmonary oedema and respiratory muscle weakness - orthopnoea breathlessness on lying flat
- paroxysmal nocturnal dyspnoea
dyspnea that occurs during lying down/sleeping forcing sudden awakening of the patient. this occurs due to blood redistribution during lying down causing increase venous blood in the lungs causing transudation of plasma into the alveolar spaces
how do you ask patient about paroxysmal nocturnal dyspnoea
ask how many pillows they use to sleep at night
why does exercise intolerance occur
due to inability of the heart to raise the CO during exercise - it is already at the limit of its cardiac output.
fatigue and lethargy occur due to compromised CO leading to tissue hypo perfusion. muscle tissues are one of the tissues that undergo atrophy and altered metabolism due to hypo perfusion, causing lethargy and fatigue, as well as exercise intolerance when it involves respiratory muscles
can you have a cough or wheeze with HF
yes, the cough is usually worse at night however, the classical pink frothy sputum is rarely seen
what are the signs of HF
fluid overload
Pulsus alternans
Hypotension
Tachycardia
Cardiac heave
Displaced Apex Beat
gallop (S3)
bilateral crepitations
cardiomegaly on CXR
cachexia
hepatic tenderness
what are the signs of fluid overload
peripheral oedema
ascites
elevated JVP
why does fluid overload occur
predominantly due to right heart failure causing blood congestion in systemic circulation, causing increased venous pressure, therefore fluid transudation into interstitial spaces.
these spaces can be the lungs, ankles, sacrum and liver
where is the apex beat normally felt and where is it felt in cardiomegaly
Normal apex beat is felt around the 5th intercostal space at the mid-clavicular line
In cardiomegaly it may be displaced lateral and / or distally (down and out)
what is the classic criteria used to diagnose HF
Framingham Criteria
what has this criteria been superseded by
the use of echocardiography
what test in the UK is used to stratify patients in primary care
the use of a blood test for BNP (brain (or “B-type”) natriuretic peptide) – particularly N-terminal pro-B-type natriuretic peptide (NT-proBNP) is used to stratify patients in primary care
how can an echocardiogram confirm diagnosis of HF
- showing a reduced ejection fraction
- showing a normal ejection fraction, but demonstrating other signs of heart failure, such as LV hypertrophy, left atrial enlargement or diastolic dysfunction
what does diagnosis of congestive HF using the Framingham criteria require
simultaneous presence of 2 Major or 1 Major and 2 Minor criteria, which provide for a 100% sensitivity (but 78% specificity) value when diagnosing the symptoms and signs of CHF
what is the pneumonic for major
SAW-PANIC
what does SAW stand for
- S3 heart sound present (gallop sound)
- Acute pulmonary oedema (left side of heart is unable to clear fluid from the lungs)
- Weight loss of more than 4.5kg in 5 days when treated (patients lose their retained fluids)
what does PANIC stand for
- paroxysmal nocturnal dyspnoea
- abdominojugular reflux
- neck vein distended (i.e elevated JVP at rest)
- increased cardiac shadow on X ray
- crackles heard in lungs
what is the pneumonic for minor
HEART-VINO
what does HEART stand for
- hepatomegaly
- effusion, pleural
- ankle oedema bilaterally
- exeritonal dyspnoea
- tachycardia
- vital capacity decreased by a third of maximum value
- nocturnal cough
