Cardiac Failure Flashcards
What is the definition of cardiac failure?
Inability of the cardiac output to meet the body’s demands despite normal venous pressures
What is the aetiology of low output cardiac failure?
LOW OUTPUT Cardiac Failure (reduced cardiac output)
A) Left Heart Failure
- Ischaemic heart disease
- Hypertension
- Cardiomyopathy
- Aortic valve disease
- Mitral regurgitation
B) Right Heart Failure
- Secondary to left heart failure (in which case it is called congestive cardiac failure)
- Infarction
- Cardiomyopathy
- Pulmonary hypertension/embolus/valve disease
- Chronic lung disease
- Tricuspid regurgitation
- Constrictive pericarditis/pericardial tamponade
C) Biventricular Failure:
- Arrhythmia
- Cardiomyopathy (dilated or restrictive)
- Myocarditis
- Drug toxicity
What is the aetiology of high output cardiac failure?
HIGH OUTPUT Cardiac Failure (increased demand)
Anaemia
Beri beri
Pregnancy
Paget’s disease
Hyperthyroidism
Arteriovenous malformation
What is the epidemiology of cardiac failure?
10% > 65 yrs old
What are the presenting symptoms of left heart failure?
Symptoms are caused by pulmonary congestion
Dyspnoea - divided based on the New York Heart Association classification:
1 - no dyspnoea
2 - dyspnoea on ordinary activities
3 - dyspnoea on less than ordinary activities
4 - dyspnoea at rest
Orthopnoea
Paroxysmal nocturnal dyspnoea
Fatigue
What are the presenting symptoms of acute left ventricular failure?
Dyspnoea
Wheeze
Cough
Pink frothy sputum
What are the presenting symptoms of right heart failure?
Swollen ankles
Fatigue
Increased weight (due to oedema)
Reduced exercise tolerance
Anorexia
Nausea
What are the signs of left heart failure upon examination?
Tachycardia
Tachypnoea
Displaced apex beat
Bilateral basal crackles
S3 gallop (caused by rapid ventricular filling)
Pansystolic murmur (due to functional mitral regurgitation)
What are the signs of acute left ventricular failure upon examination?
Tachypnoea
Cyanosis
Tachycardia
Peripheral shutdown
Pulsus alternans = Arterial pulse waveforms showing alternating strong and weak beats and is a sign of left ventricular systolic impairment
Gallop rhythm
Wheeze (cardiac asthma)
Fine crackles throughout lung
Why does acute left ventricular failure cause pulsus alternans?
In left ventricular dysfunction, ejection fraction significantly decreases leading to a reduction in stroke volume
This causes an increase in end-diastolic volume
This means that the left ventricle is stretched more for the next contraction
Due to Starling’s Law, the increased stretch of the left ventricle caused by the increased end-diastolic volume following the previous beat leads to an increase in the strength of the myocardial contraction
This results in a stronger systolic pulse
What are the signs of right heart failure upon examination?
Raised JVP
Hepatomegaly
Ascites
Ankle/sacral pitting oedema
Signs of functional tricuspid regurgitation
What are the appropriate investigations when suspecting heart failure?
Bloods
- FBC
- U&E
- LFTs
- CRP
- Glucose
- Lipids
- TFTs
CXR: (ABCDE)
- Alveolar shadowing (bat wings - alveolar oedema)
- Kerley B lines - interstiital oedema
- Cardiomegaly
- Upper Lobe Diversion
- Pleural Effusion
ECG
- May be normal
- May show ischaemic changes (pathological q waves, t wave inversion)
- May show arrhythmia or left ventricular hypertrophy
Echocardiogram
- Assess ventricular contraction
- Systolic dysfunction = LV ejection fraction < 40%
- Diastolic dysfunction = decreased compliance of the myocardium leads to restrictive filling defect
Swan-Ganz Catheter
- Allows measurement of right atrial, right ventricular, pulmonary artery, pulmonary wedge and left ventricular end-diastolic pressures
What additional investigations are required for acute left ventricular failure?
ABG
Troponin
BNP
- Raised plasma BNP suggests diagnosis of cardiac failure
- Low plasma BNP rules out cardiac failure (90% sensitivity)
What is the management of acute left ventricular failure?
Treating Cardiogenic Shock:
- This is severe cardiac failure with low blood pressure
- Requires the use of inotropes (e.g. dobutamine)
- Managed in ITU
Treating Pulmonary Oedema:
- Sit the patient up
- 60-100% Oxygen (and consider CPAP)
- Diamorphine (venodilator + anxiolytic)
- GTN infusion (venodilator –> reduced preload)
- IV furosemide (venodilator and later diuretic effect)
- Monitor: BP, Respiratory rate, Oxygen saturation, Urine output and ECG
TREAT THE CAUSE! (e.g. MI, arrhythmia)
What is the management of chronic left ventricular failure?
Chronic Left Ventricular Failure
- TREAT THE CAUSE (e.g. hypertension)
- TREAT EXACERBATING FACTORS (e.g. anaemia)
-> Check Laz’s
