Heart Failure Flashcards
The closure of which valves cause the first heart sound, S1?
Mitral and tricuspid
The closure of which valves cause the second heart sound, S2?
Aortic and pulmonary
What is systole?
When the ventricles contract and push blood from ventricles into circulation
What is diastole?
When the ventricles relax and fill with blood
What is heart failure?
A syndrome that can result from any structural or functional cardiac disorder that impairs the ability of the heart to function as a pump to support a physiological circulation
Describe the cardiac cycle
Right side:
vena cava –> RA –> tricuspid valve –> RV –> pulmonary valve –> pulmonary trunk –> pulmonary arteries –> lungs
Left side:
pulmonary veins –> LA –> mitral valve –> LV –> aortic valve –> aorta
What is stroke volume?
The volume ejected by a ventricle
What is preload?
The degree of stretch in the ventricles at the end of diastole
What is end-diastolic volume?
The blood in a ventricle at the end of diastole
What is end-diastolic pressure?
The pressure in the LV following the completion of diastolic filling
What is preload proportional to?
Stroke volume
What is afterload?
The pressure needed to be overcome in order to pump blood from the ventricle into the circulation
What can cause afterload to be higher?
Hypertension
Stenosis of the aortic valve
What can reduce afterload?
When the ventricular wall is thickened
What is systolic heart failure, what does it usually affect and what can it be caused by?
When the ventricle can’t pump blood effectively during systole
Usually affects LV
Increased afterload, damaged muscle, hypertrophy
What is diastolic heart failure?
When the heart chambers can’t fill with blood in diastole
What is compliance?
How easy a chamber is to fill
When can ventricular compliance be reduced?
Impaired ventricular relaxation
Hypertrophy
What are some systemic causes of heart failure?
Anaemia
Sepsis
Hyperthyroidism
Liver failure
Excess fluid
What is left ventricular failure and what can it then cause?
Persistently elevated ventricular pressure in LV
Pulmonary oedema and SOB (which is worse when lying down –> PND)
What is right ventricular failure?
RV is not pumping as efficiently as it should be
What is the most common cause of right-sided heart failure?
Left-sided heart failure
High pulmonary pressure from LV –> excessive afterload in RV –> works harder and fails
Treatment of heart failure
Decreased cardiac output in heart failure is sensed by baroreceptors and kidneys –>
Stimulates RAAS –>
Increases pumping of heart and body retains fluid
This helps initially but ultimately increases afterload which causes more heart failure
Drugs try and remove these effects –> help the heart function or assist kidneys to remove excess fluid
Pacemaker or implantable defibrillator
What is a heart murmur, what can they be caused by and what can they be in terms of timing?
Heard when blood flow through the heart is turbulent
Caused by stenosis (narrowing) or regurgitation (leaky valve)
Can be systolic or diastolic in timing
What best describes the timing of a systolic murmur?
Between S1 and S2
What best describes the timing of a diastolic murmur?
Between S2 and S1
Describe how Starling’s forces can lead to oedema in heart failure
In heart failure, pressure backs up in the venous system which then backs up into the capillaries, so hydrostatic pressure is greater than oncotic pressure –> fluid forced out into tissues causing oedema
Name the 2 types of drugs which can be used to treat heart failure, how they can help heart failure and give some examples of each drug
ACEi - lisinopril, ramipril, captopril, enalapril
Beta blockers - bisoprolol, carvedilol, nebivolol
These drugs block the compensatory response to heart failure which improves symptoms
Which drug can also treat heart failure by increasing the force of contraction?
Digoxin
It has a positive inotrope effect which inhibits the Na+/K+ ATPase pump –> increased concentration of intracellular Ca –> more forceful contractions
Which type of drugs can be used to relieve SOB?
Loop diuretics
Furosemide, bumetanide, torasemide
Reduces solute reabsorption in thick ascending limb of LoH
Promotes urinary excretion of solutes and water
