Cardiac Embryology Flashcards

Question

Patent Ductus Arteriosus

Answer 1

Ductus arteriosus is a vessel leading from the bifurcation of the pulmonary artery to the aorta just distal to the left subclavian artery Normally, open in the fetus but closes immediately after birth (O2 tension, bradykinins) Flow across a patent ductus is determined by the pressure and resistance relationships between the systemic and pulmonary circulations and by the cross-sectional area and length of the ductus

Answer 2

vessel resistance (R) is directly proportional to the length (L) of the vessel and the viscosity (η) of the fluid/air, and inversely proportional to the radius to the fourth power (r4)

Answer 3

Pulmonary pressures are normal A gradient and shunt from aorta to pulmonary artery persist throughout the cardiac cycle Characteristic thrill and a continuous "machinery" murmur with late systolic accentuation at the upper left sternal edge

Answer 4

Pulmonary vascular obstruction (Eisenmenger syndrome) with pulmonary hypertension Right-to-left shunting Cyanosis from unoxygenated blood shunting to the descending aorta Toes—but not the fingers—become cyanotic and clubbed, a finding termed differential cyanosis.

Answer 5

Cardiac failure Infective endocarditis Pulmonary vascular obstruction may cause aneurysmal dilatation, calcification, and rupture of the ductus

Answer 6

Closure recommended in adults without severe pulmonary vascular disease & R to L shunt Surgical ligation and division Transcatheter closure using coils, buttons, plugs, and umbrellas has become commonplace for appropriately shaped defects Thoracoscopic surgical approaches are considered experimental Closure deferred for several months after infective endocarditis because the ductus may remain edematous and friable

Answer 7

Separation or lack of fusion between the media of the aorta and the annulus of the aortic valve Rupture usually occurs 3rd or 4th decade of life Most often fistula between R coronary cusp and R ventricle Occasionally fistula is between non-coronary cusp and R atrium Abrupt rupture causes chest pain, bounding pulses, continuous murmur accentuated in diastole, volume overload of the heart Medical management is directed at cardiac failure, arrhythmias, or endocarditis

Answer 8

Two-dimensional and Doppler echocardiographic studies Cardiac catheterization quantitates the left-to-right shunt Thoracic aortography visualizes the fistula

Answer 9

aneurysm is closed and amputated and the aortic wall is reunited with the heart, either by direct suture or patch/prosthesis

Answer 10

Unusual anomaly - communication between a coronary artery and another cardiac chamber, usually the coronary sinus, right atrium, or right ventricle Shunt is usually of small magnitude and myocardial blood flow is not usually compromised; Shunt large - coronary "steal" syndrome with myocardial ischemia and possible angina or ventricular arrhythmias

Answer 11

Infective endocarditis Thrombus formation with occlusion or distal embolization with myocardial infarction Rupture of an aneurysmal fistula Rarely - pulmonary hypertension and congestive failure

Answer 12

Loud, superficial, continuous murmur at the lower or midsternal border usually prompts a further evaluation of asymptomatic patients. Doppler echocardiography demonstrates the site of drainage; if the site of origin is proximal, it may be detectable by two-dimensional echocardiography Angiography (classic catheterization, CT, or magnetic resonance angiography) permits identification of the size and anatomic features of the fistulous tract, which may be closed by suture or transcatheter obliteration

Answer 13

Myocardial infarction and fibrosis commonly lead to death within the first year 20% of patients survive to adolescence and beyond without surgical correction Diagnosis - ECG findings of an anterolateral MI & left ventricular hypertrophy (LVH) Surgery - CABG (with internal mammary artery graft or saphenous vein)

Answer 14

One of the most common congenital heart malformations, not always detectable Murmur harsh systolic More common in males than in females May initially be functionally normal Bicuspid valves may develop stenosis or regurgitation with time or be the site of infective endocarditis

Answer 15

Medical ? Prophylaxis against infective endocarditis ? Patients with diminished cardiac reserve, the administration of digoxin and diuretics and sodium restriction while awaiting operation. Dilated aortic root may require beta blockers. Surgical – aortic valve replacement Critical obstruction (aortic valve area <0.45 cm2/m2 Symptoms 2nd secondary LV dysfunction or myocardial ischemia Hemodynamic evidence of LV dysfunction Aortic balloon valvuloplasty Asymptomatic children/adolescent/young adults with critical aortic stenosis without calcifications When surgery contraindicated balloon valvuloplasty may provide short-term or bridge to value replacement with CHF

Answer 16

Discrete form of subaortic stenosis consists of a membranous diaphragm or fibromuscular ring encircling the LV outflow tract just beneath the base of the aortic valve Jet impact from the subaortic stenotic jet on the underside of the aortic valve leads to progressive aortic valve fibrosis and valvular regurgitation Echocardiography demonstrates the anatomy of the subaortic obstruction; Doppler studies show turbulence proximal to the aortic valve; quantitate the pressure gradient and severity of aortic regurgitation Treatment - complete excision of the membrane/fibromuscular ring

Answer 17

Localized or diffuse narrowing of the ascending aorta just above the level of the coronary arteries at the superior margin of the sinuses of Valsalva Coronary arteries are subjected to elevated systolic pressures, often dilated, tortuous, atherosclerotic Most patients have a genetic defect for the anomaly (located in the same chromosomal region as elastin on chromosome 7

Answer 18

Narrowing or constriction of the lumen of the aorta, most often distal to the origin of the left subclavian artery near the insertion of the ligamentum arteriosum Occurs in 7% of patients with congenital heart disease, is more common in males than females, and is particularly frequent in patients with gonadal dysgenesis (e.g., Turner syndrome)

Answer 19

Site Extent of obstruction Associated cardiac anomalies; bicuspid aortic valve (up to 75% association) Circle of Willis aneurysms may occur in up to 10%, high risk of sudden rupture and death

Answer 20

ECG - may show LV hypertrophy CXR - may show dilated left subclavian artery high on the left mediastinal border, dilated ascending aorta, indentation of the aorta at the site of coarctation and pre- and poststenotic dilatation (the "3" sign) along the left paramediastinal shadow - essentially pathognomonic

Answer 21

Most children/young adults with isolated, discrete coarctation are asymptomatic Headache, epistaxis, cold extremities, and claudication with exercise may occur 1st findings may be heart murmur and HTN in upper extremities; low or delayed pulses in femoral arteries on PE Enlarged and pulsatile collateral vessels may be palpated in the intercostal spaces anteriorly, in the axillae, or posteriorly in the interscapular area Upper extremities and thorax may be more developed than the lower extremities Midsystolic murmur over the left interscapular space may become continuous if the lumen is narrowed sufficiently to result in a high-velocity jet across the lesion throughout the cardiac cycle Additional systolic and continuous murmurs over the lateral thoracic wall may reflect increased flow through dilated and tortuous collateral vessels

Answer 22

Surgical resection and reanastomosis Percutaneous catheter balloon dilatation with stent placement Late postoperative systemic hypertension in the absence of residual coarctation is related partly to the duration of preoperative hypertension Follow-up of rest and exercise blood pressures is important; many have systolic hypertension only during exercise, in part due to a diffuse vasculopathy.

Answer 23

RV outflow obstruction localized to the supravalvular, valvular, or subvalvular levels or occur in any combination Multiple peripheral sites of narrowing seen in rubella embryopathy & familial and sporadic forms of supravalvular aortic stenosis Valvular pulmonic stenosis (PS) is the most common form of isolated RV obstruction

Answer 24

Severity of the obstructing lesion, rather than the site of narrowing, main determinant of the clinical course and symptoms Mild PS - peak systolic pressure gradient 50 mmHg indicates severe PS – severity may progress Moderate - 30-50 mmHg - fatigue, dyspnea, RV failure, and syncope may limit the activity of older patients, where cardiac output may not increase with exertion

Answer 25

Systolic pressure in the RV may exceed that in the LV, because the ventricular septum is intact RV ejection is prolonged with moderate or severe stenosis Sound of pulmonary valve closure is delayed and soft RV hypertrophy reduces the compliance of that chamber Forceful RA contraction is necessary to augment RV filling 4th heart sound Prominent a waves in the jugular venous pulse Presystolic pulsations of the liver reflect vigorous atrial contraction

Answer 26

ECG Mild PS – normal Severe PS – RV hypertrophy CXR Mild or moderate PS – normal heart size and pulmonary vascularity Valvular stenosis – dilatation of main and left pulmonary arteries (2nd to jet and intrinsic media weakness) Severe obstruction – RV hypertrophy with reduced pulmonary vessels Two-dimensional echocardiography visualizes pulmonary-valve morphology; the outflow tract pressure gradient is quantitated by Doppler echocardiography

Answer 27

Cardiac catheter technique of balloon valvuloplasty is usually effective Direct surgical relief of moderate and severe obstruction may be accomplished at a low risk Multiple stenoses of the peripheral pulmonary arteries are usually inoperable Some proximal branch or bifurcation lesions of the main PA may be surgically corrected or undergo balloon dilatation and stenting

Answer 28

Malaligned VSD RV outflow obstruction Overriding aortic (over VSD) RV hypertrophy due to the RV's response to aortic pressure via the large VSD

Answer 29

Severity of RV outflow obstruction determines the clinical presentation Hypoplasia of the RV outflow tract varies from mild to complete (pulmonary atresia) Pulmonary valve stenosis and supravalvular and peripheral pulmonary arterial obstruction may coexist Rarely, there is unilateral absence of a pulmonary artery (usually left) Right-sided aortic arch and descending thoracic aorta occur in 25%

Answer 30

Determined by relationship between the resistance of blood flow from the ventricles into the aorta and into the pulmonary artery When the RV outflow obstruction is severe, pulmonary blood flow is reduced markedly, and a large volume of desaturated systemic venous blood shunts right-to-left across the VSD Severe cyanosis and erythrocytosis occur In many infants and children, the obstruction is mild but progressive

Answer 31

``` Tet Spell RV infundibular contractility Catecholamine release Hyperventilation w/ increased WOB R to L shunt ``` ``` Treatment Increase SVR Increase R filling pressure Reduce catecholamine release Supplemental O2 ```

Answer 32

ECG RV hypertrophy CXR Normal-sized, boot-shaped heart (coeur ‘heart’ en sabot ‘wooden shoe worn in some European countries’) Prominent right ventricle Concavity in the region of the pulmonary conus Pulmonary vascular markings are typically diminished Aortic arch and knob may be on the right side (25%) Two-dimensional echocardiography Malaligned VSD with the overriding aorta and variable site and severity of PS

Answer 33

Balloon or blade catheter or surgical creation interatrial communication in the neonate increases intracardiac mixing of systemic and pulmonary venous blood Systemic pulmonary–artery anastomosis may be indicated in the patient with severe obstruction to LV outflow and diminished pulmonary blood flow

Answer 34

Only a few adults with tetralogy of Fallot have not had some form of previous surgical intervention Reoperation in adults is most commonly for severe pulmonary regurgitation Long-term problems with ventricular function Ventricular and atrial arrhythmias occur, requiring medical treatment, electrophysiologic study & ablation Interventional catheterization may be needed in selected patients (i.e., angioplasty and stenting of branch pulmonary stenosis) Aortic root has a medial tissue defect; it is commonly enlarged and associated with aortic regurgitation Endocarditis remains a risk despite surgical repair

Answer 35

Dextro- or d-transposition of the great arteries Aorta arises rightward anteriorly from the RV Pulmonary artery emerges leftward and posteriorly from the LV Results in two separate parallel circulations (some communication between them must exist after birth to sustain life) Most have intra-atrial communication 2/3 have PDA 1/3 have associated VSD .

Answer 36

Transposition is more common in males 10% of cyanotic heart disease Clinical course influenced by Degree of tissue hypoxemia Ability of each ventricle to sustain an increased workload in the presence of reduced coronary arterial oxygenation Nature of associated cardiovascular anomalies Status of the pulmonary vascular bed By 30 yo, 30% of patients will have developed decreased RV function and progressive tricuspid regurgitation and CHF Pulmonary vascular obstruction develops by one to two years of age in patients with an associated large VSD or large PDA in the absence of obstruction to LV outflow

Answer 37

Intracardiac repair by rearranging the venous returns (intra-atrial switch, i.e., Mustard operation) Systemic venous blood is directed to the mitral valve then LV then PA Pulmonary venous blood is diverted through the tricuspid valve and right ventricle to the aorta Late survival after these repairs is good Arrhythmias (e.g., atrial flutter) or conduction defects (e.g., sick sinus syndrome) occur in 50% of such patients by 30 years after the intra-atrial switch surgery Progressive dysfunction of the systemic subaortic right ventricle with risk of tricuspid regurgitation, ventricular arrhythmias, or cardiac arrest and late sudden death

Answer 38

Patients with VSD with severely obstructed LV outflow tract Operation uses an intracardiac ventricular baffle and extracardiac prosthetic conduit to replace the pulmonary artery (Rastelli procedure)

Answer 39

Two fundamental anatomic abnormalities Transposition of the ascending aorta and pulmonary trunk Inversion of the ventricles. Desaturated systemic venous blood passing from the right atrium through the mitral valve to the LV and into the pulmonary trunk, Oxygenated pulmonary venous blood flows from the left atrium through the tricuspid valve to the RV and into the aorta. Circulation is corrected functionally

Answer 40

Clinical presentation and prognosis determined by: Nature and severity of any complicating intracardiac anomalies Development of dysfunction of the systemic subaortic RV 1/3 of patients by 30 yo develop progressive RV dysfunction and tricuspid regurgitation Ebstein-type anomalies of the left-side tricuspid atrioventricular valve are common VSD or PS due to obstruction to outflow from the right-sided subpulmonary (anatomic left) ventricle may coexist. Complete heart block occurs at a rate of 2–10% per decade

Answer 41

Total anomalous pulmonary venous connection (showing pulmonary veins connected to the left innominate vein) superior vena cava atrial septal defect left innominate vein pulmonary veins Oxygenated blood returning from the lungs is routed back into the superior vena cava, rather than the left atrium Presence of an atrial septal defect is necessary to allow partially oxygenated blood to reach the left side of the heart

Answer 42

Partial anomalous pulmonary venous drainage location where right pulmonary veins normally enter left atrium right pulmonary veins entering right atrium Oxygenated blood flows from the right pulmonary veins into the right atrium instead of into the left atrium

Answer 43

Associated lesions: Interatrial communication; Commonly, hypoplasia of the right ventricle and pulmonary artery Clinical presentation includes severe cyanosis due to obligatory admixture of systemic and pulmonary venous blood in the left ventricle ECG characteristically shows RA enlargement, left-axis deviation, and LV hypertrophy

Answer 44

Downward displacement of the tricuspid valve into the right ventricle Anomalous attachment of the tricuspid leaflets Tricuspid valve tissue is dysplastic Tricuspid regurgitation “Atrialized" portion of the RV lying between the atrioventricular ring and the origin of the valve, which is continuous with the RA chamber RV is often hypoplastic

Answer 45

Progressive cyanosis from right-to-left atrial shunting Symptoms due to tricuspid regurgitation and RV dysfunction Paroxysmal atrial tachyarrhythmias with or without atrioventricular bypass tracts [Wolff-Parkinson-White (WPW) syndrome

Answer 46

CXR – cardiomegaly, RA enlargement, decreased pulmonary vascularity Two-dimensional echocardiography shows abnormal positional relation between the tricuspid and mitral valves with abnormally increased apical displacement of the septal tricuspid leaflet Tricuspid regurgitation is quantitated by Doppler examination Surgery with prosthetic replacement of the tricuspid valve when the leaflets are tethered or repair of the native valve

Answer 47

CXR Dextrocardia Hyperinflation of the lungs Linear tram-track opacities suggestive of bronchiectasis Kartagener syndrome (part of ciliary dyskinesia / immobile cilia syndrome) Autosomal recessive disease with extensive genetic heterogeneity Abnormal ciliary motion Impaired mucociliary clearance Situs inversus

Answer 48

complete situs inversus (situs inversus totalis) chronic sinusitis bronchiectasis telecanthus : widened interpupillary distance by a nasal polyp azoospermia Radiographic changes are much milder than in cystic fibrosis

Answer 49

Positional anomaly - cardiac apex Right side of the chest (dextrocardia) Midline (mesocardia) Left side of the chest but abnormal position of the viscera (isolated levocardia) Mirror-image dextrocardia with complete situs inversus usually has normal cardiac findings otherwise Malposition of the abdominal organs relative to cardiac multiple cardiac anomalies are usually present

Answer 50

Ectopia cordis, ectocardia or exocardia, is a rare congenital defect, resulting in herniation of the heart through a sternal, pericardial and/or abdominal defect Defect in the fusion of the anterior chest wall Pentalogy of Cantrell defects in diaphragm midline supra-umbilical abdominal wall defect pericardium hear lower sternum congenital intracardiac abnormalities

Answer 51

Single ventricular chamber with complex or common atrioventricular valves Associated anomalies Abnormal great artery positional relationships Pulmonic valvular or subvalvular stenosis Subaortic stenosis Survival to adulthood depends on a relatively normal pulmonary blood flow with normal pulmonary resistance and good ventricular function. Modifications of the Fontan approach with systemic to pulmonary artery anastomoses

Answer 52

Except for ligation of an uncomplicated patent ductus arteriosus, almost every other surgical repair leaves behind or causes some abnormality of the heart and circulation that may range from trivial to serious Cardiac operations importantly involving the atria, such as closure of ASD, repair of total or partial anomalous pulmonary venous return, or venous switch corrections of complete transposition of the great arteries (the Mustard or Senning operations), may be followed years later by sinus node or atrioventricular node dysfunction or by atrial arrhythmias (especially atrial flutter) Intraventricular surgery may also result in electrophysiologic consequences, including complete heart block necessitating pacemaker insertion to avoid sudden death Valvular problems may arise late after initial cardiac operation Progressive stenosis of an initially nonobstructive bicuspid aortic valve in the patient who underwent aortic coarctation repair Cleft mitral valve may become progressively regurgitant after repair of the ostium primum ASD Tricuspid regurgitation may be progressive in the postoperative patient with tetralogy of Fallot (when RV outflow tract obstruction was not relieved with initial surgery) Following surgically modified CHD, inadequate relief of an obstructive lesion, residual regurgitant lesion or shunt will lead to myocardial dysfunction Patients who were cyanotic for many years before repair, have a preexisting compromise in ventricular performance

Answer 53

Prosthetic cardiac valve History of infective endocarditis Congenital heart disease (CHD) (except for the conditions listed, antibiotic prophylaxis is no longer recommended for any other form of CHD): (1) unrepaired cyanotic CHD, including palliative shunts and conduits; (2) completely repaired congenital heart defect with prosthetic material or device, whether placed by surgery or by catheter intervention, during the first 6 months after the procedure; and (3) repaired CHD with residual defects at the site or adjacent to the site of a prosthetic patch or prosthetic device (which inhibits endothelialization) Cardiac transplantation recipients with cardiac valvular disease