CVD - Cardiac failure Flashcards Preview

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Flashcards in CVD - Cardiac failure Deck (15):

Define cardiac failure
- common cause
- 3 types

•Cardiac Output less than Body Needs
•Usually due to reduced Cardiac Output

1. Rarely due to increased Body Needs
–“high output heart failure”

2. Usually due to reduced systolic function
–Low ejection fraction

3. May be due to stiff diastolic function
–Normal ejection fraction


How (4) is the cardiac output determined?

- Input (preload)
- rate (heart rate)
- strength (contractility)
- resistance (afterload)


(4) causes of oedema

•Increased venous pressure
–Heart failure

•Decreased osmotic pressure
–Plasma protein loss: renal or liver failure

•Blocked lymphatics

•Increased capillary permeability

NOTE: to do with venous pressure not arterial


Discuss the compensation of cardiac failure & its consequence

Maintain the same CO by increasing ventricular end diastolic pressure. But this compensation leads to pulmonary & systemic congestion due to fluid retention. (oedema in legs & lungs)

In severe heart failure, CO is low PLUS lungs are congested


Explain the pathogenesis of fluid retention in cardiac failure

Low CO -> low renal blood flow -> activation of RAAS -> fluid, Na+ retention, K+ loss & vasoconstriction -> increase BP & CO


Explain the association between sympathetic nervous system & cardiac failure
- initial consequence
- longterm consequence

Cardiac failure -> sympathetic nervous system stimulated -> increased noradrealine -> increased INITIAL contractility.

BUT longterm deleterious effect:
- vasoconstriction
- ventricular arrhythmias
- direct toxic effect


(7) causes of cardiac failure

•Ischaemic heart disease: myocardial infarct
•Valvular heart disease
•Hypertensive heart disease
•Congenital heart disease
•Cor pulmonale (right heart)
•Pericardial disease


(2) possible causes of cardiomyopathy

- alcohol
- cytotoxic drugs


What should you ask in Hx to see if the patient has cardiac failure?

–Previous myocardial infarct(s)
–PHx Rheumatic Fever -> Valve Defect
–Known murmur -> Valve Defect
–PHx Hypertension – Degree of control
–PHx Congenital Heart Defect
–Possible causes of cardiomyopathy: alcohol, Cytotoxic Drugs
–PHx Lung Disease: Asthma, COPD, Cystic Fibrosis, Pulmonary Fibrosis


What does increased JVP usually correlate with?

Increased pulmonary venous pressure

I.e. left & right heart failure

NOTE: but it can be elevated with NORMAL pulmonary venous pressure due to pure RIGHT heart failure


(3) causes of right heart failure

•Pulmonary Hypertension
–Cor Pulmonale: Heart Failure due to Lung Disease. Eg COPD, Cystic Fibrosis, Pulmonary Fibrosis
–Pulmonary Embolism

•Right sided structural disease
–Pulmonary or Tricuspid Valves
–R Ventricular Cardiomyopathy

•Pericardial disease


What % of ejection fraction is mild, moderate & severe?

•40-50% Mild
•30-40% Moderate


What are the (4) principles of treatment of heart failure?

•Reduce the venous pressure
–Relieves congestion & oedema
–But without reducing Cardiac Output too much (too low CO & reduced BP may be dangerous)

•Block the Renin-Angiotensin-Aldosterone system
–Produces long-term fluid loss and vasodilatation

•Block the Sympathetic Nervous System (β)
–Block the direct cardiac toxic effect of β stimulation

•Treat the underlying & precipitating cause


Common (5) agents for Rx of cardiac failure

•Diuretics – eg frusmide
•Aldosterone Antagonists eg spironolactone
•Angiotensin Converting Enzyme (ACE) inhibitors eg ramipril
•Angiotensin Receptor Antagonists eg irbesartan
•Beta Blockers eg carvedilol


(3) surgical/mechanical Rx of cardiac failure

•Biventricular Pacing – Cardiac Resynchronisation
–Improves cardiac function

•Implantable Cardioverter Defibrillator
–Because ventricular arrhythmias and sudden death are common in heart failure

•Cardiac Assist Devices & Transplantation
–For a small group who do not respond to other treatment

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