Cardiac Failure

Question 1

Define Cardiac Failure

Answer 1

Cardiac failure is the clinical syndrome resulting from the inability to maintain an adequate cardiac output.

Question 2

Cardiac Failure Epidemiology

Answer 2

It affects 1-2% of those aged ≥65 years and 10% of those aged ≥75 years. The prognosis is poor, in severe heart failure ≥50% die within 3 years.

Question 3

Cardiac Failure Pathogenesis

Answer 3

Heart failure has many causes but the results are similar. An inadequate CO stimulates compensatory resembling the response to hypovolaemia. These become maladaptive

• Neurohormonal activation causes
  
  1. renin-angiotension-aldosterone system to promote salt and water retention and peripheral vasoconstriction
  2. release of ADH resulting in further water retention and vasoconstriction.
• Ventricular dilatation
  * impaired systolic function and fluid retention increase ventricular volume (or dilatation).
  * A dilated heart is mechanically inefficient. If energy is limited (eg. coronary disease) this may lead to further damage and neuro activation.

Question 4

Cardiac Failure Main Causes

Answer 4

• Ischaemic heart disease (35-40%)
  
  • Cardiomyopathy (dilated) (30-34%)
  • HTN (15-20%)
  • Other include:
    
    • Valvular disease
    • Myocarditis
    • Atrial septal defect.
    • Lung disease
    • Thyrotoxicosis

Question 5

Cardiac Failure Classification

Answer 5

• Acute heart failure
  * Largely synonymous with left heart failure and results in a sudden failure to maintain CO.
  * There is insuffient time for compensatory mechanisms and the clinical picture is dominated by APO.
• Chronic heart failure
  * Largely synonymous with right heart failure.
  * There is a gradual decline in CO and compensatory mechanisms dominate the picture.
  * Both left and right commonly co-exist, usually because left HF leads to secondary pulmonary HTN and right HF.

Question 6

Cardiac Failure Presentation

Answer 6

• Left heart failure
  * SoB:
  * orthopnoea (laying down)
  * paraoxysmal nocturnal dyspnoea (at night).
  * Signs of tachypnoea, tachycardia
  * Bibasilar inspiratory pulmonary crepitations (APO)
• Right heart failure
  * Fluid retention in legs, ascites.
  * Signs of raised JVP and peripheral oedema.
• Chronic heart failure
  * The heart enlarges (cardiomegaly)
  * Secondary MR/TR occurs.
  * Cardiac cachexia may be present.

Question 7

Cardiac Failure NY Heart Association Classification

Answer 7

Class I

• No limitation
• No symptoms during usual activity

Class II

• Mild limitation
• Comfortable with rest or with mild exertion

Class III

• Moderate limitation
• Comfortable only at rest

Class IV

• Severe limitation
• Any physical activity brings on discomfort and symptoms occur at rest

Question 8

Cardiac Failure Provoking/Exacerbating factors

Answer 8

• Arrythmia (AF)
  
  • Drug issues (non-compliance, fluid retaining drugs, NSAIDs)
  • Anaemia
  • Infection (pneumonia, UTI)
  • Thyroid disease.

Question 9

Cardiac Failure Investigations

Answer 9

• Echocardiography - for diagnosing aetiology
• ECG - determining cardiac size, diagnosing old MI, LVH, arrhythmias
• Chest X-ray - large heart, APO (Kerley B lines)
• Cardiac catheterization - exclude coronary artery disease

Question 10

Cardiac Failure Management

Answer 10

• Fluid retention
  * Diuretics
• Control of Hypertension
  * ACE inhibitors
  * AIIRBs
• Rate control
  * β-blockers
  * Metoprolol, carvedilol & bisoprolol
  * SE of bardyarrhythmia, hypotension
  * Cease in acute episodes.
  * Digoxin
  * digox used when RAS fails
  * It has positive inotropic effects.
• Anticoagulation
  * Warfarin
  * Dabigatran
• Multisite ventricular pacing

Question 11

Cardiac Failure Complications

Answer 11

• Thromboembolism
  
  • AF - commonly complicates CCF, rate control (digox & βBs) are indicated.
  • Progressive pump failure - may respond to increasing doses of diuretics. Transplant may be an option.
  • Ventricular arrhythmias - common, resultant sudden cardiac death causes up to 50% of deaths in CHF.