Development of Heart Flashcards
No. of heart defects
1:200 babies
Cyanotic Heart lesions
Right to Left
Mix of O2 poor systemic blood with O2 rich pulmonary blood
Septal defects, patent ductus arteriosus
Acyanotic Heart lesions
Left to Right
Narrowed valves or vessels that greatly increase the workload of the heart
Generally structural problems
Coarctation of Aorta
Heartbeat Detected first
day 22
Heart develops from this tissue
Cardiogenic mesoderm
Primitive heart tube formation
Day 21
Sinus venosus becomes
Right atrium, IVC + coronary sinus
Primitive atria become
R + L auricles, and left atrium
Atrioventricular sulcus divides
Atria from primitive ventricle
Primitive ventricle becomes
Left Ventricle
Interventricular sulcus divides
Primitive ventricle from bulbus cordis
Bulbus cordis 1/3 becomes
Muscular RV
Bulbus cordis 2/3 becomes
Smooth outflow of RV and LV
Truncus arteriosus becomes
Asc Aorta
Pulmonary trunk
Situs invertus occurrence
1:7000
Endocardial cushions derived from
Neural crest
Septum primum appearance
day 28
Ductus arteriosus
Shunts blood pulmonary trunk –> ascending aorta (lungs bypassed)
Ductus arteriosus reasons
Protects lungs against circulatory overload Allows RV to strengthen High pulmonary vascular resistance Low Pulmonary blood flow Moderately saturated blood
Ductus venosus
Shunts blood from umbilical vein to IVC
Bypasses liver
Flow regulated via sphincter
Ductus venosus reasons
Conducts highly oxygenated blood
Foramen ovale
Bypasses pulmonary circulation
Shunts highly oxygenated blood RA –> LA
Umbilical vein becomes
Ligamentum Teres
Mesentry becomes
Falciform ligament
Ductus venosus becomes
Ligamentum venosum of liver
Foramen ovale becomes
Fossa ovalis
Foramen Ovale Change mechanism
Decreased flow from placenta and IVC –> lower pressure in RA
Decreased pulmonary vascular resistance secondary to lung expansion
Increase pulmonary blood flow
Higher LA pressure compared to IVC
Closure due to higher LA pressure than RA
Ductus arteriosus becomes
Ligamentum arteriosum
Ductus arteriosum change mechanism
Closed by increased paO2
Closure mediated by bradykinin
What may reopen Ductus arteriosus
Prostaglandin E2
Tetralogy of Fallot
Overriding aorta arising directly above septal defect
RV hypertrophy
Ventricular Septal defect
Narrow RV flow
Cyanotic Heart lesions
Tetralogy of Fallot
Truncus Arteriosus
Transposition of the Great Vessels
Persistent Truncus Arteriosus
Single artery comes from heart- supplies both aorta + pulmonary artery
Large VSD allows mixing of R + L ventricular blood
Transposition of the Great Vessels
Aorta + pulmonary artery switched
blue baby
Acyanotic Heart Diseases
Atrial Septal Defects
Ventricular Septal Defects
Patent Ductus Arteriosus
Atrial Septal Defect
Hole between 2 atria
7:10000 births
2:1 prevalence F:M
Asymptomatic first 3 decades of life
Ventricular Septal Defect
25% congenital birth defects
Many close spontaneously- 30-50%
90% in membranous septum- L->R of blood + pulmonary hypertension
10% in muscular septum- L->R of blood
Patent Ductus Arteriosus
Connection between descending aorta to main pulmonary trunk
Near origin of left subclavian
Coarctation of Aorta
Constriction may be above or below ductus arteriosus
Pre-ductal= allow blood flow
Post-ductal= Collateral circulation must be established
Coarctation of Aorta diagnosis
Systematic hypertension
Secondary LVH with heart failure
Decreased lower extremity pulses
Coarctation of aorta treatment
Balloon angioplasty
Patent ductus arteriosus diagnosis
Prostaglandin inhibitor- ibuprofen
Clip above 3 months (surgery)
