Cardiac failure Flashcards
(33 cards)
Define heart failure
Also known as congestive heart failure (CHF) and congestive cardiac failure (CCF), is when the heart is unable to pump sufficiently to maintain blood flow to meet the body’s metabolic needs.
Epidemiology
Heart failure is common: in the United Kingdom the prevalence is 1-2%. The average age at diagnosis is 75 years old.
Elderly population, incidence higher with age
In Europe and North America the most common causes are coronary artery disease, hypertension, and valvular disease.
Rare cause in Although Europe and North America (significant in Central/South America) –> Chagas disease
Systolic vs diastolic HF
Low output heart failure can be further classified into that caused by:
- pump failure
- arrhythmias
- excess after-load
- excess pre-load.
Pump failure may be caused by
1. diastolic dysfunction (impaired ventricular filling during diastole) or
2. systolic dysfunction (impaired myocardial contraction during systole).
Causes of systolic heart failure
Ischaemic heart disease
Dilated cardiomyopathy
Myocarditis
Infiltration (e.g. in haemochromatosis or sarcoidosis)
Causes of diastolic heart failure
Hypertrophic obstructive cardiomyopathy
Restrictive cardiomyopathy
Cardiac tamponade
Constrictive pericarditis
Define high output heart failure
Cardiac output is normal, but there is an increase in peripheral metabolic demands which exceed those that can be met with maximal cardiac output.
Causes of high-output heart failure (AAPPTT)
Anaemia
Arteriovenous malformation
Paget’s disease
Pregnancy
Thyrotoxicosis
Thiamine deficiency (wet Beri-Beri)
Clinical features of left heart failure
- Pulmonary congestion (pressure builds up behind the left heart i.e. in the lungs)
- systemic hypoperfusion (reduced left heart output).
- can push RV into failure, leading to CHF
Pulmonary congestion
1. Signs
2. Symptoms
- Tachypnoea
Bibasal fine crackles on auscultation of the lungs - Shortness of breath on exertion
Orthopnoea
Paroxysmal nocturnal dyspnoea
Nocturnal cough (± pink frothy sputum)
Systemic hypoperfusion
1. Signs
- Cyanosis
Prolonged capillary refill time
Hypotension
Less common signs of LHF
- Pulsus alternans (an alternating strong and weak pulse)
- S3 gallop rhythm (produced by large amounts of blood striking a compliant left ventricle)
- Features of functional mitral regurgitation - fatigue, shortness of breath and oedema
Clinical features of right heart failure
- venous congestion (pressure builds up behind the right heart)
- pulmonary hypoperfusion (reduced right heart output).
Venous congestion
1. Signs
2. Symptoms
- Raised JVP
Pitting ankle/sacral oedema
Tender smooth hepatomegaly
Ascites
Transudative pleural effusions (typically bilateral) - Ankle swelling
Weight gain
Abdominal distension and discomfort,
Anorexia/nausea.
NYHA classification of HF
classify severity of cardiovascular disability through severity of exertional dyspnoea limiting activity, or discomfort at rest.
- Class I - no limitation in physical activity, activity does not cause undue fatigue, palpitation or dyspnoea
- Class II - slight limitation of physical activity, and comfort at rest. Ordinary physical activity causes fatigue, palpitation and/or dyspnoea.
Class III - marked limitation in physical activity, but comfort at rest. Minimal physical activity causes fatigue (less than ordinary).
Class IV - inability to carry on any physical activity without discomfort, with symptoms occurring at rest. If any activity takes place, discomfort increases.
Investigations
- ECG - can reveal ischaemic changes or arrhythmias
- NT-proBNP
- >2000ng/L the patient needs an urgent 2 week referral for specialist assessment and an ECHO.
- 400-2000ng/L the patient should get a 6 week referral for specialist assessment and an ECHO. - ECHO
- Bloods
- CXR
NT-proBNP
N-terminal pro-B-type natriuretic peptide
BNP is released by the ventricles in response to myocardial stretch.
BNP has a high negative predictive value, so if the BNP is not raised the diagnosis of congestive cardiac failure is highly unlikely.
If the BNP is raised, the patient should be referred for trans-thoracic echocardiogram.
SEE flashcard 30 for difference between BNP and NT-proBNP
Echo
Ventricular dysfunction is normally measured by the ejection fraction.
<40% = heart failure is reduced ejection fraction
Greater than 40% but raised BNP = Heart failure with preserved ejection fraction
Blood tests
U+Es to assess renal function (for medication) and to look for hyponatraemia
LFTs for hepatic congestion
TFTs to check for hyperthyroidism
Glucose and lipid profile to assess modifiable cardiovascular risk factors
BNP is significantly associated with a diagnosis of heart failuare
CXR findings
A: Alveolar oedema (with ‘batwing’ perihilar shadowing)
B: Kerley B lines (caused by interstitial oedema)
C: Cardiomegaly (cardiothoracic ratio >0.5)
D: upper lobe blood diversion
E: Pleural effusions (typically bilateral transudates)
F: Fluid in the horizontal fissure
Lifestyle modifications
Smoking cessation
Salt and fluid restriction (this improves mortality)
Supervised cardiac rehabilitation
Pharmacological management
- ACE-inhibitor and beta-blocker (bisoprolol, carvedilol, or nebivolol) (these improve mortality)
- Consider angiotensin receptor blocker (ARB) if intolerant to ACE inhibitors
- Consider hydralazine and a nitrate if intolerant to ACE-I and ARB. - Loop diuretics such as furosemide or bumetanide improve symptoms (but NOT mortality)
- If symptoms persist and NYHA Class 3 or 4 consider:
- Aldosterone antagonists such as spironolactone or eplerenone. These drugs also improve mortality (2nd line)
- for Afro-Caribbean patients - hydralazine and a nitrate
- if in sinus rhythm and impaired ejection fraction - Ivabradine
- Angiotensin receptor blocker - Digoxin - useful in those with AF. This worsens mortality but improves morbidity.
Surgical/device management options
Surgical/device management options
- ICD if
1. QRS interval <120ms, high risk sudden cardiac death, NYHA class I-III
2. QRS interval 120-149ms without LBBB, NYHA class I-III
3. QRS interval 120-149ms with LBBB, NYHA class I
Surgical/device management options
Surgical/device management options
- ICD if
1. QRS interval <120ms, high risk sudden cardiac death, NYHA class I-III
2. QRS interval 120-149ms without LBBB, NYHA class I-III
3. QRS interval 120-149ms with LBBB, NYHA class II
Initial Management of acute heart failure (pulmonary oedema)
- Sit the patient up
- Oxygen therapy (aiming saturations >94% in normal circumstances)
- IV furosemide 40mg or more (with further doses as necessary) AND close fluid balance (aiming for a negative balance)
- SC morphine - this is contentious with some studies suggesting that it might increase mortality by suppressing respiration
