Valvular Disease and Heart Failure Flashcards
how to calculate cardiac output?
stroke volume x heart rate
how to calculate stroke volume?
end diastolic volume - end systolic volume
how to calculate ejection fraction?
(stroke volume/end diastolic volume) x 100
how to calculate mean arterial blood pressure?
1/3(SBP-DBP)+DBP
OR
Cardiac Output (CO) x Systemic Vascular Resistance (SVR) + central venous pressure (CVP)
define infective endocarditis
an infection caused by bacteria that enter the bloodstream and settle in the heart lining, a heart valve or a blood vessel
common symptoms of infective endocarditis
fever malaise sweats unexplained weight loss may be new heart murmur
blood tests may show what in a patient with infective endocarditis?
anaemia
raised markers of infection
what imaging can be used to help diagnose infective endocarditis?
echocardiogram
transoesophageal echo
an echocardiogram can show what in a patient with infective endocarditis?
vegetation
abscess
valve perforation and/or new dehiscence of prosthetic valve. often regurgitation of affected valve
why is a transoesophageal echo better than a transthoracic echo in diagnosing infective endocarditis?
it has a higher sensitivity
what is Duke’s criteria for infective endocarditis?
A set of criteria to determine the likelihood of an individual having infective endocarditis
list major criteria for infective endocarditis
Persistently +ve blood culture for typical organisms
ECHO: vegetation, dehiscence of prosthetic valve, abscess
New valvular regurgitation murmur
Coxiella burnetti infection
list minor criteria for infective endocarditis
Predisposing heart condition /IV drug use
Fever >38 C
Vasc: emboli to organs, brain
Immuno: glomerulonephritis, Oslers nodes, Roth spots
+ve blood cultures that do not meet specific criteria
what is the most common causative bacteria for endocarditis?
streptococcus
enterococci
staph aureus
gram -ve bacteria
what cardiac features of decompensation would you look for?
symptoms: SOB, freq coughing, leg/abdo swelling, fatigue
clincal signs: ^JVP, lung crackles, oedema
what other features of decompensation would you look for?
Vascular and embolic phenomena
(stroke, Janeway lesions, splinter/ conjunctival haemorrhages)
Immunological phenomena
(Osler’s nodes, Roth spots)
define decompensation
inability of the heart to maintain inadequate circulation
what part of the heart does infective endocarditis affect?
Infective endocarditis affects the endocardium, especially the valves of the heart
what heart valve is affected most frequently in infective endocarditis?
Aortic valve is affected most frequently (aortic > mitral > right-sided valves)
why does infective endocarditis affect the valves more commonly?
formation of a vegetation at valves > change to their thickness or a failure in their ability open + close appropriates > bacteria to attach to the endocardium if underlying damage is present, occurs more frequently at sites of turbulent blood flow
why are IV drug users at an increased risk of infective endocarditis?
due to repeated injection – potentially exposing their bloodstream to bacteria on the surface of the skin or use of non-sterile needles
increased risk of infective endocarditis is in what populations?
IV drug users
complication of routine surgeries
immunosuppressed individuals
individuals w/ congenital heart defects
treatment of infective endocarditis
meds: antibiotics for infection
surgery: may have to remove/replace damaged valves
prophylaxis for those with congenital heart defects
define dilated cardiomyopathy
characterised by dilated and thin-walled cardiac chambers with reduced contractility
what does a echocardiogram show in a patient with dilated cardiomyopathy?
dilated left ventricle with reduced systolic function (ejection fraction) and typically global hypokinesis
what are common causes of dilated cardiomyopathy?
idiopathic, genetic, toxins (alcohol, cardiotoxic chemotherapy), pregnancy (peripartum cardiomyopathy), viral infections (myocarditis), tachycardia-related cardiomyopathy, thyroid disease, muscular dystrophies
what genes have been implicated in the diagnosis of dilated cardiomyopathy?
mutations in genes encoding cardiac cytoskeletal proteins e.g. Titin, Lamin, Phospholamban, cardiac myosin binding protein C, myosin heavy chain
how is dilated cardiomyopathy managed?
Medical HF therapy - ACEi, beta-blockers, mineralocorticoid receptor antagonists
fluid overload > diuretics
AF > Anticoagulation
Cardiac devices – cardiac resynchronisation therapy and/or implantable cardioverter defibrillator
Transplant
list complications of dilated cardiomyopathy
ventricular or atrial arrhythmias, sudden death, impaired systolic and/or diastolic dysfunction, heart failure
