Valvular Disese And Heart Failure Flashcards
How do you calculate cardiac output?
stroke volume (SV) x heart rate (HR)
How do you calculate ejection fraction?
(Stroke volume/ end diastolic volume) x100
How do you calculate mean arterial pressure?
Diastolic pressure + (1/3 x systolic pressure - diastolic pressure)
- What is the cardiac output, ejection fraction and mean arterial pressure for the below case:
This is a 60 year old gentleman presenting with shortness of breath to A+E. It was diagnosed that he was in type 2 respiratory failure secondary to an infectious exacerbation of COPD. As a result he needed intensive care support and had more invasive monitoring. A Schwanz ganz catheter was inserted which measured end diastolic volume as 142ml and end systolic volume as 47 ml. Observations were that this patient was intubated and ventilated using BiPAP of 20/5 with saturations of 95 percent, heart rate 75 beats per minute, respiratory rate 12/minute, blood pressure 115/75mmHg and Temperature 36.5 degrees Celsius.
CO= SV x HR = (142-47) x 75 = 7,125 ml/min = 7.125L/min
Ejection fraction = (SV / EDV) x100 = (142-47) / 142 x100 = 67%
Mean arterial pressure =diastolic pressure + (1/3(systolic - diastolic)) = 75+(1/3(115-75) = 88.3mmHg
What is infective endocarditis?
infective endocarditis is an infection of the endocardium or vascular endothelium of the heart
How do you diagnose infective endocarditis?
Fever, malaise, sweats and unexplained weight loss are common symptoms
•There may be a new heart murmur on examination
•Blood tests show anaemia and raised markers of infection
•Blood cultures may isolate a microorganism
•Echocardiogram can show a vegetation, abscess, valve perforation and/or new dehiscence of prosthetic valve. Often there is regurgitation of the affected valve
•Transoesophageal echo has higher sensitivity compared with transthoracic
What features of heart decompensation would you look for in infective endocarditis?
Symptoms include shortness of breath, frequent coughing, swelling of the legs and abdomen, fatigue
•Clinical signs include raised JVP, lung crackles and oedema
What part of the heart does infective endocarditis affect?
Infective endocarditis affects the endocardium, especially the valves of the heart
•Aortic valve is affected most frequently (aortic > mitral > right-sided valves)
It is more common for bacteria to attach to endocardium if_____
Underlying damage is present - this occurs more frequently at sites of turbulent blood flow such as the valves of the heart
Why are intravenous drug users at 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.
What is the definition of dilated cardiomyopathy?
dilated cardiomyopathy is characterised by dilated and thin-walled cardiac chambers with reduced contractility
What are the most common causes of dilated cardiomyopathy?
Idiopathic, genetic, toxins (alcohol, cardiotoxic chemotherapy), 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, mineralocorticoid receptor antagonists
Diuretics for fluid overload
Anticoagulation for atrial fibrillation
Cardiac devices – cardiac resynchronisation therapy and/or implantable cardioverter defibrillator
Transplant
What genes are implicated in the diagnosis of dilated cardiomyopathy?
Mutations in genes encoding cytoskeleton proteins e.g. Titin, lamin, phospholamban, cardiac myosin binding, protein C, myosin heavy chain
