Session 10 - Heart Failure Flashcards
What is the definition of heart failure?
Clinical syndrome of reduced cardiac output, tissue hypoperfusion, increased pulmonary pressures and tissue congestion
What are 3 clinical signs of heart failure?
Dyspnoea
Fatigue
Tissue fluid retention
What is the pathophysiology of heart failure?
Remodelling of cardiac muscle in response to other conditions changes ventricular function and shape/size impairs ventricular filling or emptying
What are 2 main types of heart failure?
HFrEF - heart failure with reduced ejection fraction
HFpEF - heart failure with preserved ejection fraction
What is end diastolic pressure?
How full the heart is filled up, higher volume = higher pressure
How is cardiac output and end diastolic volume related?
Increasing end diastolic volume causes increased stretch which means greater stroke volume ejected in systole, therefore increasing cardiac output
When heart failure becomes severe, how is the relationship between cardiac output and end diastolic volume affected?
Contractility is impaired, lowers force of contraction, when end diastolic volume increases, cardiac output falls
How does a heart fail with preserved ejection fraction?
Ejection fraction preserved because end diastolic volume decreases and amt of blood pumped out decreases, ventricular chamber size is reduced
What are 2 possible causes for heart filling problem?
Ventricular chambers too stiff
Ventricular walls thickened
How does a heart fail with reduced ejection fraction?
Cannot pump with enough force (contraction problem), poor ventricular contraction so unable to empty it well
What are 3 possible causes for heart failure with reduced ejection fraction?
Muscle walls thin or fibrosed
Chamber space enlarged
Abnormal or uncoordinated myocardial contraction
What is the effect of neuro-hormonal activation on heart failure?
Leads to increased cardiac demand and further reduction in stroke volume
What are 2 neurohumoral mechanisms activated by reduced blood pressure?
Baroreceptor detect and increases sympathetic drive
Kidneys detect lowered renal perfusion and activate renin-angiotensin-aldosterone pathway
What are the 2 immediate effects of increased sympathetic drive and overall effect?
Increased heart rate and peripheral resistance, increasing afterlpad and hence increasing cardiac work
What is the effect of activating renin-angiotensin-aldosterone (RAAS) pathway?
Increases circulating volume due to Na+ and water retention because of aldosterone and stimulated anti-diuretic hormone, increasing preload
Enhanced sympathetic activity and vasoconstriction increases afterload
Overall increased cardiac work
How does pulmonary oedema occur on heart failure?
Increased LV pressure as failure to eject volume sufficiently, increases pressure in pulmonary circulation, increasing hydrostatic pressure at venule end of pulmonary capillary beds, nett force pushes fluid out into interstitial, increases volume of tissue fluid accumulates in pulmonary interstitial
What are 4 symptoms of pulmonary oedema?
Breathlessness
Basal pulmonary crackles
Orthopnoea
Paroxysmal nocturnal dyspnoea
How does peripheral oedema occur in heart failure?
Increased RV pressure as failure to eject, increase pressure in systemic venous circulation, increases central venous pressure and jugular venous pressure, increases hydrostatic pressure at venule end of capillary beds, increased volume of tissue fluid accumulates in interstitial
What are 2 symptoms of peripheral oedema?
Bulging jugular vein
Lower limb pitting oedema
What is the most common cause of RV failure?
LV failure
What is congestive heart failure?
Both ventricles fail
What is the cause of isolated RV failure?
Chronic lung disease
What is a symptom of congestive heart failure?
Accumulation of fluid in interstitial of pulmonary and peripheral tissues
What is the effect of IV furosemide?
Immediate venodilatory effect, can clear fluid from lungs
What are 4 effects of beta blockers?
Reduce heart rate
Reduce blood pressure
Reduce mobilization of glycogen
Negate unwanted effects of catecholamines
What is the role of ACE inhibitor?
Inhibit renin-angiotensin-aldosterone system, reduce water retention, vasoconstriction and sympathetic activity
What is the effect of aldosterone receptor antagonists / spironolactone?
When aldosterone concentration doesn’t respond to ACE-inhibitors, aldosterone still can interact but spironolactone prevents it from interacting w receptors
What are 4 tests to investigate heart failure?
ECG
CXR
Bloods
Echo
What are the 3 blood tests to do when investigating heart failure?
NTpro-BNP
FBC
U&Es
