structural heart diseases Flashcards
What are the layers of the heart?
myocardium, endocardium inside, epicardium outside
What are the 2 heart sounds?
closure of atrioventricular valves and semi-lunar valves
What is p-wave? T wave? Qrs?
p - atrial depolarisation
qrs - ventricular depolarisation
t-ventricular repolarisation
Why atrial contraction? How much does it usually contribute to filling of ventricle and when does this change
Atrial contraction to top up after passive filling. Usually contributes 10% but more during exercise, or when heart beat increases
What is end-systolic volume? End-diastolic volume? Stroke volume?
End-systolic volume is volume left in LV after systole. End-diastolic volume is volume in LV before ejection. Stroke volume is end-diastolic volume - end-systolic volume
What are some congenital structural heart diseases?
Ventricular septal defect, atrial septal defect, tetralogy of fallot, aortic coarctation
What types of conditions can develop later in life?
Mitral/aortic stenosis/regurgitation, cardiomyopathies
What is Ventricular septal defect VSD? What does this cause? What might it present with? If large hole what may be needed?
- VSD is when there is a hole in the ventricular septum and thus mixing of deoxy and oxy blood. Due to the pressure differences between LV and RV, oxygenated blood goes into the RV to go to the lungs, creating an increased pressure in pulmonary system and less oxygenated blood to the tissues
- presents with poor weight gain, feeding, palpitations. -Sometimes the hole closes after birth but for large holes may need surgery or cardiac catheterisation to close the hole
What is tetralogy of fallot? What is needed and why?
- VSD. 2. pulmonary stenosis 3. misplaced aorta due to widening of aortic valve 4. RV hypertrophy. Require surgeries for repair to prevent mixing of deoxy and oxy blood
What is atrial septal defect?
Hole between the 2 atria
What is coarctation of aorta? What does this lead to ? What is needed?
Coarctation (narrowing) of the descending aorta and therefore heart has to pump blood at a higher pressure and work harder to pump against narrow aorta (ventricular hypertrophy/heart failure.
-needs urgent repair
What are the 3 things that can lead to valvular defects and how common are they worldwide, age and gender wise?
Rheumatic fever common in developing countries. Calcific aortic disease - above 70 equal sexes. Degenerative mitral valve diseases - 70 -more in females.
What is more prevalent: aortic or mitral disease?
Mitral more prevalent than aortic
What is aortic stenosis preceded by?
aortic sclerosis (aortic valve thickening)
What are risk factors for aortic stenosis?
Hypertension, dyslipidaemia, smoking, congenital bicuspid valves (more prone to infections leading to stenosis), CKD, old age, radiotherapy
What are causes of aortic stenosis?
Rheumatic heart disease, congenital heart disease, calcium problems or calcification of valve
What is the pathophysiology behind aortic stenosis?
The valvular endocardium is damaged due to abnormal blood flow across the valve or another trigger and this endocardial injury leads to leaflet fibrosis and calcification causing thickening of the valve and inability for it to open completely during systole. In rheumatic disease, previous streproccocal infection targets the valvular endocardium leading to inflammation and therefore calcification
How does rheumatic disease cause aortic stenosis?
previous streprococcal infection targets valvular endocardium leading to inflammation and thus calcification/fibrosis so valve cant open all the way in systole (sclerosis & stenosis)
How does this abnormal physiology lead to problems in aortic stenosis?
Fibrosis and calcification lead to stenosis as the valve cannot open completely during systole to pump blood into the aorta/body. This increases the pressure that the LV must pump with leading to left ventricular hypertrophy in order to compensate. Can lead to left ventricular failure. Systolic function declines.
What is the history and presentation of aortic stenosis?
Chest pain, exertional dyspnoea, ejection systolic murmur with crescendo de crescendo pattern that peaks in mid-systole and radiates to the carotid. High LDL, CKD
What are investigations done in aortic stenosis?
Transthoracic echocardiography, ECG
What is management of aortic stenosis? What are options for treatment and at what stage?
Aortic valve replacement. Asymptomatic patients with severe AS LVEF <50% or undergoing other cardiac surgery. Or asymptomatic with severe or rapid progression, abnormal exercise test or high serum BNP levels. Other surgeries are balloon aortic valvuloplasty, ACE inhibitors, statins
What is aortic regurgitation and what can cause it?
failure of the aortic valve to close completely leading to backflow of blood into the left ventricle during diastole. It can be caused by incompetence of the valve leaflets due to fibrosis or other diseases or due to aortic root dilation/dissection.
Is aortic regurgitation chronic?
Can be acute or chronic. Acute is a medical emergency (Pulmonary hypertension/oedema, cardiogenic shock) or chronic
What are causes of aortic regurgitation?
Rheumatic heart disease, infective endocarditis, aortic valve stenosis which can lead to regurgitation later, bicuspid aortic valves, aortic root dilation
How does aortic root dilation/aneurysm cause AR and what are causes of aortic root dilation?
Aortic root dilation pulls the leaflets apart so they cannot close properly during diastole. This can be due to connective tissue disorders like marfan’s syndrome, or idiopathic.
What is pathophysiology of acute aortic regurgitation?
Infective endocarditis leads to rupture of the leaflets and vegetations (masses) on the valvular cusps can cause inadequate closure. Chest trauma can also cause tear in aorta leading to AR
What is pathophysiology of chronic aortic regurgitation?
Rheumatic fever can cause fibrosis/calcification of the leaflets and inadequate closure