The cardiovascular system - Heart failure and cardiomyopathy Flashcards
What is heart failure?
Heart failure is a syndrome that results from an inability of the heart to maintain an adequate output
Describes the epidemiology of heart failure
- Incidence increases with age
- Median age at first presentation is 76 years
- Men most affected
Describe the aetiology of heart failure
Vascular
- Ischaemic/coronary heart disease (50%0
- Hypertension
Muscular
- Dilated cardiomyopathy
- Hypertrophic cardiomyopathy
- Congenital heart disease
Valvular
- Stenotic valve
- Regurgitant valves
Electrical
- Arrythmias
High output
- Anaemia
- Septicaemia
- Thyrotoxicosis
- Liver failure
Describe the pathophysiology of heart failure
As cardiac output begins to decline, compensatory mechanisms (both mechanical and neurohumeral) are activated to sustain adequate tissue perfusion
However, while these mechanisms may initially be beneficial, they eventually lead to worsening of heart failure over time as they decline their ability to compensate
Give 4 compensatory mechanisms that are activated to sustain an adequate cardiac output in heart failure
- Increasing preload
- Increasing heart rate
- Activation of the renin-angiotensin-aldosterone system
- Sympathetic nervous system activation
Describe how an increase in pre-load compensates for heart failure
Increase in pre-load causes an increase in end-diastolic volume (EDV) compensating for the reduced ejection fraction, thus maintaining cardiac output
Describe how the the activation of renin-angiotensin system compensates for heart failure
Angiotensin II increases preload and after load
This leads to increased cardiac output
Why does Ace inhibition cause the ace cough and angiodema
The ace cough develops because angiotensin converting enzyme catalyses bradykinin into inactive fragments
Ace inhibition therefore leads to an increase in bradykinin levels, which leads to side-effects of cough and angioedema
Give the 4 classifications of heart failure
- Acute vs chronic heart failure
- Systolic vs diastolic heart failure
- Left-sided vs right-sided heart failure
- High output vs low output heart failure
Describe acute vs chronic heart failure including the causes
Acute
- Characterised by rapid onset of symptoms and/or signs of heart failure that is usually life-threatening
- May present suddenly with cardiogenic shock or sub acutely with decompensation of chronic heart failure
- Requires urgent evaluation and treatment
- Most common cause include acute myocardial dysfunction, acute valvular, pericardial tamponade
Chronic
- Characterised by progressive symptoms with episodes of acute deterioration
- Due to progressive cardiac dysfunction from structural and/or functional abnormality
- Usually precipitated by conditions that affect muscle (e.g., cardiomyopathy), vessels (e.g., ischaemic heart disease), valves (e.g., aortic stenosis), or conduction (e.g., AF)
Describe systolic (HFrEF) vs diastolic heart failure (HFpEF) including the causes
Systolic
- aka heart failure with reduced ejection fraction (HFrEF)
- Poor ventricular contraction leads to reduced ejection fraction in left ventricle (< 40%)
- commonly seen because of ischaemic heart disease, dilated cardiomyopathy, myocarditis, infiltration (e.g., haemochromatosis or sarcoidosis)
Diastolic
- aka heart failure with preserved ejection fraction (HFpEF)
- Ventricles are unable to relax due to stiffness, resulting in inadequate filling of the heart during diastole (LVEF > 50%)
- Seen in restrictive cardiomyopathy, constrictive pericarditis, cardiac tamponade, hypertrophic obstructive cardiomyopathy
What is the LVEF in heart failure with reduced LVEF (HFrEF)?
LVEF < 40%
What is the LVEF in heart failure with reduced LVEF (HFmrEF)?
LVEF 40-49%
What is the LVEF in heart failure with preserved LVEF (HFrEF)?
LVEF >/= 50%
Describe left-sided vs right-sided heart failure
LHF
- Left-side is usually affected first
- Poor ventricular contraction causes blood ‘back up’ in the lungs
- This increases the pulmonary vein hydrostatic pressure, resulting in pulmonary oedema
RHF
- Most common cause of RHF is left heart failure
- An increase in the pressure of the pulmonary vasculature causes the right side of the heart to pump against increased resistance. The right side of the heat compensates with ventricular dilatation and eventual failure
What are the 3 broad categories that right-sided heart failure is related to?
- Pulmonary hypertension
- Pulmonary/tricsupid valve disease
- Pericardial diseases
a) What is cor pulmonale?
b) What is the ECG appearance of cor pulmonale?
a) Right heart failure secondary to long-standing pulmonary arterial hypertension e.g., COPD
b) Shows p pulmonale, which refers to tall, peaked p wave. It reflects right atrial enlargement
Describe low output vs high output heart failure including the causes
Low output
- Compensatory mechanisms eventually fail, resulting in a reduced cardiac output
- Caused by either failure of the pump (heart), increased preload or increased after load
- Characterised by weak pulse, cool peripheries, and low blood pressure
- Low-output states are seen in ischaemic heart disease, aortic stenosis
High output
- The heart is unable to meet the increased demand of perfusion despite normal or increased cardiac output
- The problem is with reduced vascular resistance, often due to diffuse arteriole vasodilation or shunting
- LVEF > 50% and abnormal diastolic filling
- Echocardiogram is typically normal
- It is generally due to states of increased metabolic demand (e.g., hyperthyroidism aka thyrotoxicosis), reduced vascular resistance (e.g., thiamine deficiency, sepsis) or significant shunting (e.g., large arteriovenous fistula), Paget’s disease, pregnancy, anaemia
- Characterised by warm peripheries and normal pulses
What are is low cardiac output and high cardiac output heart failure characterised by?
Low output
- Weak pulse
- Cool peripheries
- Low blood pressure
High cardiac output
- Warm peripheries
- Normal pulses
What does the echocardiogram in high-cardiac output heart failure look like?
Echocardiogram is typically normal
Heart failure
a) Symptoms
b) Signs
a)
- Shortness of breath
- Wheeze
- Fatigue
- Weight loss
- Orthopnoea (breathless lying down)
- Paroxysmal nocturnal dyspnoea (waking up at night breathless)
- Palpitations
b)
- Raised JVP
- Displaced apex
- Crackles]- Ankle oedema
- Heart sounds S3/S4
- Ascites (fluid collects in spaces within your abdomen)
- Pulses alternans (an alternating strong and wake pulse) - associated with severe LHF
- Right sided heart failure: peripheral oedema (pedal, scrotal or sacral), raised JVP, hepatomegaly and bloating
What are the symptoms and signs of left-sided heart failure?
Symptoms
- Dysponea
- Fatigue
- Tachycardia - gallop rhythm
- Orthopnoea
- Paroxysmal nocturnal dysponea
Signs
- Displaced apex beat
- Pleural effusion
- Bibasall crackles
- Pulsus alternans
What are the signs of right sided heart failure?
- Peripheral oedema (pedal, scrotal or sacral)
- Raised JVP
- Hepatomegaly
- Bloating
What are the differential diagnosis of heart failure?
- Obesity
- Chest disease: including lung, diaphragm or chest wall
- Venous insufficiency in lower limbs
- Drug-induced ankle swelling (e.g., dihydropyridine calcium channel blockers)
- edu-induced fluid retention (e.g., NSAIDs)
- Angina
- Hypoalbuminemia
- Intrinsic renal or hepatic disease
-Pulmonary embolic disease - Depression and/or anxiety disorder
- Severe anaemia or thyroid disease
- Bilateral renal artery stenosis