Valvular Disorders & Heart Failure Flashcards
How is cardiac output calculated?
Stoke volume x heart rate
What is cardiac output
The volume of blood the heart pumps in a minute
What units is cardiac output usually given in?
L/min
How is ejection fraction calculated?
(stroke volume/ end diastolic volume) x100
What is ejection fraction?
The volumetric fraction of blood ejected by the ventricle
What units is ejection fraction given in?
%
What are the 2 ways mean arterial pressure calculated?
Cardiac output x systemic vascular resistance + central venous pressure
OR
diastolic pressure + 1/3( systolic pressure- diastolic pressure)
What is mean arterial pressure?
Average arterial pressure through a single cardiac cycle
What are the units of mean arterial pressure?
mm Hg
What should mean arterial pressure be for there to be adequate perfusion?
65 mm Hg or above
What is characteristic of infective endocarditis?
Fever and new heart murmur
What is infective endocarditis?
Infection of the endocardium
What is the endocardium?
The innermost lining of the heart
How many layers are there in the lining of the heart? What are they called?
There are 3, from innermost to outermost they are:
Endocardium
Myocardium
Pericardium
What is the most common cause of infective endocarditis?
Streptococcus
How will patients with infective endocarditis present?
Fever, malaise, breathlessness, chest pain, fatigue, coughing
What set of criteria are used to diagnose infective endocarditis?
Duke’s criteria
What part of the heart does infective endocarditis most effect?
The left side and its valves as this is where most blood flows and where theres turbulent blood flow
aortic valve > mitral > right sided valves
How are IV drug users a concern in infective endocarditis?
They are at higher risk due to frequent intravenous injections- they may also present irregularly with more right sided problems as when injected, this is the first place bacteria in the blood will flow to
What is dilated cardiomyopathy?
Dilation in the heart walls with impaired contractibility
What are some complications of dilated cardiomyopathy?
Ventricular/atrial arrhythmias, sudden death, heart failure, impaired systolic and diastolic function
What mutated genes are associated with dilated cardiomyopathy?
Mutations in genes encoding cardiac cytoskeletal proteins eg titin, lamin, phospholamban etc
How is cardiac myopathy managed?
ACE inhibitors, beta blockers, diuretics for fluid overload, anticoagluation meds for atrial fibrillation, cardiac devices eg internal defribillator
What are signs of decompensation in infective endocarditis?
SOB, coughing, fatigue, swelling of legs and abdo
Clinical signs: JVP, lung crackles and oedema
Other complications: Vascular and embolic phenomena (stroke, Janeway lesions, splinter/ conjunctival haemorrhage) Immunological phenomena (Osler's nodes, Roth spots)
What does echocardiography for dilated cardiomyopathy show?
Dilated left ventricle with reduced systolic function and global hypokinesis
What are the commonest causes of dilated cardiomyopathy?
Pregnancy Idiopathic Genetic Toxins (alcohol, chemo) viral infections (myocarditis) thyroid disease muscular dystrophy tachycardia related cardiomyopathy
Who is at increased risk of infective endocarditis?
IV drug users
Complication of routine surgery e.g. dental surgery
Immunosuppressed individuals
Individuals with congenital heart defect
How do you diagnose infective endocarditis?
Fever, malaise, swear and unexplained weight loss
Might be new heart murmur
Bloods show anaemia and raised infection markers
Blood cultures might isolate microorganism
Echo might show vegetation, abscess, valve perforation or dehiscence of prosthetic valve
Transesophageal echo has higher sensitivity than transthoracic echo
