Valvular Disease and Heart Failure Flashcards
How do you calculate cardiac output?
cardiac output = heart rate x stroke volume
How can you calculate stroke volume?
stroke volume = end diastolic volume - end systolic volume
What is cardiac output?
volume of blood the heart pumps in one minute (L/min or cm3/min)
How do you calculate ejection fraction?
ejection fraction = stroke volume / end diastolic volume x 100
What is ejection fraction?
the volumetric fraction of blood ejected by the ventricles with each given contraction (%)
How can you calculate mean arterial pressure when under stress?
mean arterial pressure = (cardiac output x systemic vascular resistance) + central venous pressure
How can you calculate the mean arterial pressure at rest (estimated)?
mean arterial pressure = diastolic pressure + 1/3 (systolic pressure - diastolic pressure)
What is infective endocarditis?
- an infection of the endocardium/vascular endothelium of the heart
- typically affects the heart valves
What causes infective endocarditis?
- bacteria entering the blood stream and forming a ‘vegetation’ in the endocardium
- streptococci (20-40%)
What is a ‘vegetation’?
a bacterial infection surrounded by a layer of platelets and fibrin
What are the symptoms of infective endocarditis?
- fever
- malaise
- sweats
- unexplained weight loss
What may be heard on examination with infective endocarditis?
heart murmur (new)
What may blood tests show with infective endocarditis?
- anaemia
- raised infection markers
What may blood cultures show with infective endocarditis?
microorganism (strep infection)
What may an ECG show with infective endocarditis?
- vegetation
- abscess
- valve perforation
- tearing of prosthetic valve
- regurgitation of the affected valve
What are the cardiac features of heart decompensation?
- shortness of breath
- frequent coughing
- swelling of legs and abdomen
- fatigue
- raised JVP
- lung crackles
- oedema
What are the other complications associated with heart decompensation?
Vascular and embolic phenomena - stroke - Janeway lesions - splinter/conjunctival haemorrhages Immunological phenomena - Osler's nodes - Roth spots
What part of the heart does infective endocarditis effect?
endocardium, especially the valves of the heart
- most frequently: aortic valve (mitral, right-sided valves)
Why does infective endocarditis tend to effect the valves of the heart?
- formation of vegetation is more likely if underlying damage is present
- more common in sites of turbulent blood flow (heart valves)
How does infective endocarditis differ for IV drug users?
- increased risk due to repeated injection
- entry of bacteria into the blood stream is the first step of development
Which populations are at increased risk of developing infective endocarditis?
- IV drug users
- immunosuppressed
- congenital heart defects (bicuspid aortic valve)
What is dilated cardiomyopathy?
dilated and thin-walled cardiac chambers with reduced contractility
What would an Echo of dilated cardiomyopathy show?
- dilated left ventricle
- reduced systolic function (ejection fraction)
- global hypokinesis
What are the common causes of dilated cardiomyopathy?
- idiopathic
- genetic
- toxins (alcohol, cardiotoxic chemo)
- pregnancy (peripartum cardiomyopathy)
- viral infections (myocarditis)
- tachycardia-related cardiomyopathy
- thyroid disease
- muscular dystrophies
