9 - The Heart Flashcards
Development of Heart (2)
Cardiac precursors originate in lateral mesoderm on 15th day
NOTCH PATHWAY!
1st heart field is left ventricle
Di-George Syndrome Gene
TBX1
Holt-Orm Syndrome Gene
TBX5
Noonan Syndrome
PTPN11 (Signaling Protein)
All ACYANOTIC diseases have what letter in them?
D - ASD, VSD, PDA
Congenital Heart Disease: ASD Gene
GATA4
Congenital Heart Disease: DiGeorge Syndrome Gene and Defined
TBX1 Gene Mutation
Abnormality in the development of third and fourth branchial arches
Congenital Heart Disease: DiGeorge Syndrome Mnemonic
CATCH-22
Cardiac Abnormality (VSD/ASD)
Abnormal facies
Thymic aplasia (recurrent infections)
Cleft Palate
Hypocalcemica (parathyroid defet)
Congenital Heart Disease: Teralogy of Fallot Gene
NOTCH-2
Congenital Heart Disease: Environmental Factors
Congenital rubella in 1st trimester –> PDA
Maternal diabetes –> TOF, VSD
Isotretinion (Accutane) –> Transposition of great vessels
Congenital Heart Disease: General Clinical Classifications - (5)
- Left-Right Shunt
- Right-Left Shunt
- Obstruction
- Shunt is an abnormal communication between the chambers or blood vessels
- Atresia: A complete obstruction of a chamber or vessel
Congenital Heart Disease: Left-Right Shunts
ACYANOTIC and have ‘D’
ASD, VSD, and PDA
Congenital Heart Disease: Right to Left Shunts
CYANOTIC and have ‘T’ (5Ts)
Tetralogy of Fallot
Transposition of great vessels (2 switched vessels)
Tricuspid Atresia
Truncus arteriosus (1 vessel)
Total Anaomalous Pulmonary Venous Return (TAPVR)
Congenital Heart Disease: Obstructive Lesions (3)
- Coarctation of Aorta
- Aortic Stenosis
- Pulmonary Stenosis
Congenital Heart Disease: Left-Right Shunts - ASD Defined
Communication between left and right atrium
Not synonymous with patent foramen ovale (which closes 80% at age 2)
Classified based on its location
Congenital Heart Disease: Left-Right Shunts - ASD Types (3)
10% - Primum Type (associated with VSD)
90% Secundum (most common) and NOT associated with any conditions
Congenital Heart Disease: - Left-Right Shunts ASD C/F
Asymptomatic till the age of 30
Soft systolic murmur can be heard due to defect or pulmonary valve
Complications are rare
Low mortality
Congenital Heart Disease: Left-Right Shunts - ASD Treatment
Closure either by surgery or catheter
Congenital Heart Disease: Eisenmenger’s Syndrome
Left-Right Shunt (VSD, ASD, PDA) —–> Right-Left Shunt
Due to increased pulmonary blood flow –> pathologic remodeling of vasculature –> pulmonary HTN –> RVH to compensate
LATE CYANOSIS
Patent Foramen Ovale: 4)
Persistent defect even after 2 years of age
Unsealed flap opens when there is increased right ventricular pressure –> e.g. in coughing, snezzing, Valsalva
High risk of paradoxical embolization (if defect is large, any thrombus from right side can go into systemic circulation)
Congenital Heart Disease: Left-Right Shunts - VSD
Most common congenital heart disease
Free communication between right and left ventricle
Congenital Heart Disease: Left-Right Shunts - VSD Types
10% infundibular - near opening of pulmonary valve
**90% membranous type - defect within septum
Congenital Heart Disease: Left-Right Shunts - VSD C/F
MANIFEST EARLY IN PEDIATRIC AGE
50% of small muscular VSD close spontaneously
Large VSD complicates reversal of shunt and reversal of shunt and pulmonary HTN
***Risk for INFECTIVE ENDOCARDITIS (pansystolic murmur)
Congenital Heart Disease: Left-Right Shunts - PDA
PG-E2 maintains its patency
Congenital Heart Disease: Left-Right Shunts - PDA C/F
Continuous harsh machinery murmur
Pulmonary HTN and cyanosis
Congenital Heart Disease: Left-Right Shunts - PDA in Premature
Communication is between pulmonary trunk and aortic arch,
Congenital Heart Disease: Right to Left Shunts - Tetralogy of Fallot (TOF) Components
Mnemonic - PROV
- Pulmonary infundibulary stenosis
- RVH
- Overriding of the aorta
- VSD
* Commonest congenital cyanotic disease because RV is stiff
* Boot-shaped heart (from RVH) and tets spell
Congenital Heart Disease: Right to Left Shunts - TOF Clues
Child cries during feeding/while playing OR development of cyanosis during feeding or crying
Congenital Heart Disease: Right to Left Shunts - TOF Clinical Features
PULMONARY STENOSIS*
If stenosis is less than its left to right right –> ‘pink tetralogy’
Severe stenosis –> cyanotic spell
Congenital Heart Disease: Right to Left Shunts - Transposition of Great Arteries Defined (4)
RARE - survival is nil without surgical interventions
Abnormal formation of truncal aorto-pulmonary setpa
Aorta arises from the right ventricle and pulmonary artery arises from left ventricle –> so venous blood goes to systemic circulation directly because aorta arises from RV. Blood doesn’t go to lungs at all for oxygenation (no gas exchange)
Atria are normal
Congenital Heart Disease: Right to Left Shunts - Transposition - C/F (4)
Depends on the magnitude of tissue hypoxia
Complicated with marked RVH
*Increased PHT
Without surgical interventions, difficult to survive
Obstructive Lesions: Coarctation of Aorta - Defined, Forms, and Associations
Constriction of aorta
Infantile form - constriction before the origin of the ductus arteriosus
Adult form - construction after the ligamentum teres (after PDA closes)
Associated with MR, Berry Aneurysms, VSD, AND TURNER SYNDROME
Obstructive Lesions: Coarctation of Aorta - C/F
Depends on the PDA opening or closing. If severe, would occur right after birth
- Continuous murmur
- Notching of ribs
Obstructive Lesions: Coarctation of Aorta - Possible Complications Proximal to Coarctation (3)
- High BP in upper limbs
- Risk of rupture of Berry’s aneurysm
- Dilatation of aortic arch –> dissection of aorta
Obstructive Lesions: Coarctation of Aorta - Possible complications Distal to Coarctation (3)
- Decreased renal blood flow
- Poor distal pulses
- Leg claudication (gangrene)
Heart Failure/CHF: Compensatory Mechanisms (6)
- Frank-Starlings Law
- Cardiac hypertrophy/dilatation
- Activation of neurohormonal substances
- Norepinephrine
- Renin-Angiotensin
- ANP
Heart Failure/CHF: Systolic Dysfunction
Deterioration of contractile function
Reduced ejection fraction
Examples:
MI
Valvular heart disease
Hypertension
Heart Failure/CHF: Diastolic Dysfunction
Insufficient expansion of chambers during diastole
Examples:
Constrictive pericarditis
Myocardial fibrosis
Amyloid deposition
Pathophysiology of Hypertrophy
Persistent stimuli –> increase in protein synthesis –> increased mitochondria number –> increased myocyte leading to increased sarcomeres… (3)
***1. Assembled in parallel —–> Concentric hypertrophy (condition which heart following HTN is forcing AGAINST RESISTANCE: Aortic Stenosis, systemic vascular HTN)
- In series with sarcomere –> Dilatation
Pathophysiology of Hypertrophy 2 - Steps to Heart Failure
Pressure overload –> Volume overload –> increased stress (and regional dysfunction) –> cell stretch –> increase in size and mass of heart (also from increased protein synthesis and deposition of abnormal proteins) —-> Heart failure
*Microscopy: Enlarged, box shape nuclei in heart –> concentric hypertrophy **
Left Sided Heart Failure Steps
Left sided heart failure –> passive congestion in lungs –> pooling of blood in left ventricle –> organ dysfunction
Morphological Changes In Heart Failure: Heart (2)
- Hypertrophy
2. Myocyte hypertrophy with varying degree of fibrosis
Morphological Changes In Heart Failure: Lungs
- Pulmonary congestion and wet lungs
2. Perivascular and interstitial edema
Morphological Changes In Heart Failure: General (4)
- Edema in interlobular space gives rise to Kerly A and B lines radiologically (pulmonary edema in septum)
- Widening of interalveolar septum
- Accumulation of edema fluid in the alveolar spaces
* 4. Heart-failure cells (brown) –> tell-tale sign
Heart Failure/CHF: Clinical Features
Limits patient’s ability to perform the routine activities
Tired, Orthopnea, and Dyspnea
Right Heart Failure: Cause and Feature
Commonest cause s left heart failure
If cause is chronic pulmonary diseases, it is known as ‘corpulmonale’
Pulmonary HTN is a feature
Right Heart Failure is secondary to (5)
- COPDs
- Pulmonary HTN
- Repeated pulmonary thromboembolism
- Chronic sleep apnea
- Altitude sickness (Pulm HTN)
Right Heart Failure: Morphology (5)
- Pedal (ankle) and pretibial edema (dependent parts)
- Heart shows right atrial hypertrophy and dilation
* 3. Nutmeg liver: cetrilobular necrosis and areas of cardiac sclerosis - Splenomegaly
- Fluid (effusion) collects in the pleura, pericardium, and peritoneum
Infantile form of coarctation leads to? (2)
Turner syndrome with differential cyanosis (lower half of body)
Adult form of coarctation of aorta leads to? (2)
Inferior notching of the ribs and disconcoardance (no cyanosis)
Most common association with maternal diabetes?
Transposition of Great Arteries