Heart Disorders 2 Flashcards
Preductal coarctation is associated with what congenital heart defects?
VSD & Turner syndrome
Post ductal coarctation of aorta is common in which age group?
Children> adults
What is cause of death in preductal coarctation of aorta?
CHF
Why are patients suffering from post ductal coarctation at an increased risk to develop aortic dissection & berry aneurysm?
Construction distal to ligament in arteriosum-increased blood flow to subclavian artery & upper extremity-dilation of aorta-aortic dissection
Berry aneurysm-increased blood flow to brain
Why is there a difference of >10mm Hg in blood pressure between upper extremity & lower extremity in post ductal coarctation?
Constriction distal to ligament in arteriosum-increased blood volume to subclavian artery & upper extremity-decreased blood volume to lower extremity
Why is there leg claudication in post ductal coarctation?
Decreased blood volume to lower extremities-under developed musculature as compared to upper extremities
Why is there hypertension in post ductal coarctation?
Decreased blood flow to kidneys-activation of renin-angiotensin-aldosterone system-hypertension
How is blood flow maintained via collaterals in post ductal coarctation?
Internal mammary & subclavian artery
Superior epigastrium & inferior epigastrium artery
Why is there rib notching in a chest radiograph of a post ductal coarctation of aorta patient?
Formation of collaterals-enlarged pulsating internal thoracic artery-wears bone away
Why do pharyngeal strains of group A streptococcus only cause rheumatic fever?
Posses M protein-virulence factor in cells wall
When do patients develop first attack of RF?
5-15years
Why is RF an example of molecular mimicry?
Host develops antibodies against M proteins of group A streptococci-cross react with human tissue (type 2 hypersensitivity reaction)
What is the most common initial clinical finding in rheumatic heart fever?
Migratory polyartheritis
Migratory polyartheritis involves what kind of joints?
Large joints-knee, ankle, wrist
Types of carditis in RF?
Fibrinous pericarditis
Myocarditis-MC death
Endocarditis
What are Aschoff bodies?
Lesions in myocardial tissue-central area of fibrinous necrosis surrounded by anitschkow cells(reactive histiocytes)
Seen in RF
Which valves are most commonly involved in RF?
MV>AV>TV
MV regurgitation/AV regurgitation
Recurrent infection-stenosis
What are clinical features of RF?
- Migratory polyartheritis
- Carditis
- Subcutaneous nodules-extensor surface of forearm, Central fibrinous necrosis
- Sydenham’s chorea
- Erythema marginatum
Diagnosis of RF?
2 major criteria + 1 minor criteria supported by antecedent pharyngeal group A streptococcus infection
Minor criteria for RF?
- Fever
- Previous attack of RF
- Arthralgia
- Increased acute phase reactants-ESR, C-reactive protein
- First degree heart block-??
Major criteria for RF?
Migratory polyartheritis Carditis SC nodules Erythema marginatum Sydenham's chorea
Lab tests for RF?
ASO titres- >400 Todd units peak: 4-5 week after
Anti-DNAse B titres
Throat cultures
Most common type of coarctation?
Infantile (preductal) coarctation
Most common cause of mitral valve stenosis?
RF
Why is there dyspnea and rust coloured sputum with hemoptysis in mitral valve stenosis?
Mitral valve stenosis-increased work on LA during filling LV in diastole-hyper trophy and dilation of LA-backing of blood in lungs-increased pressure on pulm capillaries cause rupture-RBC enter alveoli & dyspnea due to congestion
Why is there systemic embolisation risk in mitral valve stenosis?
Atrial fibrillation is a complication-stasis of blood in LA-embolisation via aorta in systemic circuit
Why is there dysphagia for solids in mitral valve stenosis?
Mitral valve stenosis-increased work imposed on LA during filling of LV in diastole-hypertrophy and dilation-compression of esophagus
Why is there pulmonary venous HTN in mitral valve stenosis?
Mitral valve stenosis-pulmonary vein HTN-pulmonary artery HTN-RVH
Why is there an opening snap followed by an early-mid diastolic rumble in mitral stenosis?
Thickened valves-open with snap
Stenosis-increased blood volume in LA-gushes to LV-rumble mid diastolic (filling of ventricle)
What is the effect on atrial and ventricular volume and pressure in mitral valve stenosis?
Atrial volume and pressure elevated
Ventricular volume and pressure decreased
Mitral valve stenosis vs. mitral valve regurgitation occur in which phase of cardiac cycle?
Mitral valve stenosis-diastole of ventricle
Mitral valve regurgitation-systole of ventricle
Causes of MV regurgitation?
- Mitral valve prolapse (MC)
- LHF-stretching of valve ring (functional MV regurgitation)
- Rupture/dysfunction of posteromedial papillary muscle post MI
- Acute RF
Why is there eccentric hypertrophy of LA during mitral valve regurgitation?
Volume overload
Why is there pulmonary edema and cardiogenic shock in chronic de compensated phase of mitral regurgitation?
Muscle dysfunction-cannot accommodate volume-increases LV and LA pressure-backing up of blood in lungs-pulmonary edema
Why is there inspiratory crackles, cough & dyspnea in mitral valve regurgitation?
Increased pressure and volume of LA-backing up of blood in lungs
Mitral valve prolapse is commonly associated with which conditions?
Marfans, ehler-danlos, klinefelters
Why does mitral valve prolapse occur?
Defective embryogenesis-cells of meaenchymal origin-excess dermatan sulphate in MV leaflet-bulging of anterior & posterior leaflets into LA during systole
Why is there a mid systolic click followed by a mid systolic regurgitation murmur in mitral valve prolapse?
Mid systolic click-restraint by chordae tendinae
Mid systolic rumble-mitral regurgitation-gushing of blood from LA to LV
Why does decreased preload cause the murmur of mitral valve prolapse to shift towards s1 & increased preload to s2?
Decreased preload-shortens systole
Increased preload-prolongs systole
Manoeuvres/conditions that shift murmur of mitral valve prolapse towards S1?
Anxiety-increased hr-decreased filling-decreased VR-preload decreased
Standing-decreased VR
Valsalva manoeuver-holding breath with epiglottis closed-+intrathoracic pressure-decreased VR
Manoeuvres that shift murmur of mitral valve prolapse towards S2?
Reclining-increased VR-increased preload
Squatting- increased PVR-decreased emptying-increased preload
Most common cause of TV regurgitation?
Functional regurgitation due to stretching of ring in RHF
Most common cause of TV regurgitation in young adults?
Congenital heart disease
Most common cause TV regurgitation in IV drug abusers?
Infective endocarditis affecting TV
Why is a pulsating liver found in TV regurgitation?
TV regurgitation-RA dilatation and hypertrophy-back up of pressure in venous system-increased pressure in sinusoids & portal vein
What are the effects of back up of pressure in the venous system in a case of TV regurgitation?
- Pulsating liver
- Portal hypertension-ascites
- Dependent pitting edema
Why is the pansystolic murmur heard in TV regurgitation increased in intensity on holding deep inspiration?
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