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
How is dilated cardiomyopathy managed?
Medical heart failure therapy - ACE inhibitors - Beta blockers - mineralcorticoid receptor antagonists Diuretics (fluid overload) Anticoagulation (A fib) Cardiac devices - cardiac resynchronisation therapy - implantable cardioverter defibrillator Transplant
What are the complications associated with dilated cardiomyopathy?
- heart failure hospitalisation
- cardiac arrhythmias
- sudden cardiac death (ventricular arrhythmia)
- reduced survival
What is part of the major Modified Duke’s criteria to diagnose infective endocarditis?
- positive blood cultures for infective endocarditis (typical micro-organism)
- echocardiographic evidence of valvular regurgitation
What is part of the minor Modified Duke’s criteria to diagnose infective endocarditis?
- predisposing heart condition
- IV drug use
- fever
- vascular phenomena
- microbiological evidence
- immunologic evidence
According to the Modified Duke’s criteria what is required for definite infective endocarditis?
- 2 major
- 1 major + 3 minor
According to the Modified Duke’s criteria what is required for possible infective endocarditis?
- 1 major + 1 minor
- 3 minor
What is heart decompensation?
Inability of the heart to maintain adequate circulation
What is heart failure with preserved ejection fraction?
- EF >50%
- diastolic or right heart dysfunction
- diastolic dysfunction causes increased blood reservoir in pulmonary veins
- causes increased pulmonary hypertension and oedema
What is heart failure with reduced ejection fraction?
- EF <50%
- impaired left ventricular systolic function and poor blood flow via the aorta
- causes pulmonary oedema due to back flow of blood to pulmonary veins and lungs
What are the clinical signs of right heart failure?
Peripheral oedema (leg swelling, raised jugular venous pressure)
What are the signs of left heart failure?
Pulmonary oedema
What medications are used to treat heart failure with preserved EF?
Diuretics and SGLT2 inhibitors
What medications are used to treat heart failure with reduced EF?
- ACE inhibitiors
- angiotensin II receptor blockers
- beta blockers
- mineralcorticoid receptor antagonists
- SGLT2 inhibitors
- diuretics
How is heart failure monitored?
- clinical signs of fluid overload
- low O2 saturation
- NT-proBNP biomarker
- ECG
What are the clinical signs of fluid overload?
- shortness of breath
- leg swelling
- orthopnoea
- reduced exercise tolerance due to shortness of breath
