Congenital Heart Defects - PowerPoint

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					CHD
 ASD
 PDA
 VSD
 Tetrology of Fallot
 Tricuspid Artesia
 Transposition of great vessels
   Fetal Circulation                    Postnatal transition
   Oxygenated blood from Umb.       1.   With first breath, Increased
    Vein bypasses liver and joins         Alv. Pressure causes
    deoxygenated blood via DV. >          vasodilation in pul. Vessels.
    Then it joins SVC and empties    2.   Obs. Clamping induces
    in Rt atrium. > through PFO it        constriction and changes UV
    enters LA.                            to Ligamentum teres and UA
   Blood enters aorta through DA         to Medial umbilical ligaments.
    and bypasses pulm. Trunk         3.   DA becomes Ligamentum
   Some blood goes to RV but             arteriosum ( 10-15 minutes)
    through DA it again enters       4.   Foramen ovale closes and
    aorta to bypass pulm. Trunk.          becomes fossa ovalis
   Deoxygenated blood returns
    via umbilical arteries..
         Causes of central cyanosis in the neonate
 Right-to-left shunt
1) Intracardiac level: cyanotic disease, anomalous systemic
   venous connection to left atrium
2) Great vessel level: persistent pulmonary hypertension of
   the newborn
3) Intrapulmonary level: pulmonary arteriovenous
   malformation

  Ventilation/perfusion mismatch
1) Airway disease: pneumonia, aspiration, cystic
   adenomatoid malformation, diaphragmatic hernia,
   pulmonary hypoplasia, labor emphysema, atelectasis,
   pulmonary hemorrhage, hyaline membrane disease,
   transient tachypnea of the newborn
2) Extrinsic compression of lungs: pneumothorax, pleural
   effusion, chylothorax, hemothorax, thoracic dystrophy
Alveolar hypoventilation
 Central nervous system depression: asphyxia, maternal sedation,
   intraventricular hemorrhage, seizure, meningitis, encephalitis
 Neuromuscular disease: Werdnig-Hoffman disease, neonatal
   myasthenia gravis, phrenic nerve injury
 Airway obstruction: choanal atresia, laryngotracheomalacia,
   macroglossia, Pierre Robin syndrome

Hemoglobinopathy: Methemoglobinemia: congenital or secondary to
  toxic exposure Other hemoglobinopathies

Diffusion impairment
 Pulmonary edema: left-sided obstructive cardiac disease,
   cardiomyopathy, Pulmonary fibrosis, Congenital lymphangiectasia
   More than 32,000 infants (one out of every 125 to 150) are born
    with heart defects each year in the United States
   1% of newborn affected by CHD

   The development of the cardiovascular system -
    … Begins to develop toward the end of the third week

   The critical period of heart development is from day 20 to day 50
    after fertilization.

   Three shunts in the fetal circulation
     1)Ductus arteriosus
      2) Ductus Venosus
     3) Foramen Ovale
   Signs and symptoms suspicious for neonatal congenital
    heart disease
   Poor feeding: bottle feedings longer than 20 to 30
    minutes, taking too little volume, resting frequently during
    feeds, or otherwise unexplained choking, gagging and/or
    frequent vomiting with feeds
   Breathing too fast or hard, particularly increasing with
    feeds
   Persistent unexplained cough or wheeze
   Color changes: central cyanosis, persistent pallor, grey,
    Excessive sweating, even while sleeping, increasing with
    feeds and other exertion
   Excessive, unexplained irritability
   Decreased activity; increased or excessive sleepingPoor
    weight gain
    Most frequent Congenital heart
     anomalies
1.   Patent Ductus arterious
2.   Transposition of great vessels
3.   Hypoplastic left heart syndrome
4.   Tetrology of Fallots
5.   Pulmonary atresia
Classification
   Cyanotic CHD                       Acyanotic CHD
   Infants unable to achieve          Infants will able to achieve
    PaO2 of 100 % after inspiring       PaO2 of > 100 % in same
    of 100 % O2.                        condition
   Cyanosis                           Murmur
   Murmur                             Symptoms of CHF
   CXR and ECG                        Treatment vary from
   If PaO2 is low start PGE1           observation, PGE1 infusion to
    infusion.                           treatment of arrythmia
   TOF, TA, Transposition,            ASD, VSD, PDA, HLHS, Coarc
    Truncus Arteriorus,                 of aorta, av canal
    TAPVR,HLHS
Transposition of great vessles

   Most common, M:F> 2: 1
   P/E
   CXR- Egg on stick appearance
   Echo
   Catheterization- diagnostic and often therapeutic

   Treatment: if sever hypoxia of acidosis occurs, urgent
    atrial balloon septostomy and subsequent arterial switch
    operation is done
Tetrology of Fallots
( PS, RVH, Overriding aorta, VSD)
   Male predominance
   P/E
   CXR- boot shaped heart with decreased pul.
    Vascular markings.
   EKG
   Echo-diagnostic
   Tt: If Pul. Flow is ductal dependent will benefit
    from PGE1 infusion
Acyanotic Heart Diseases
 100 % O2 test
 Murmur
 Signs of CHF
 VSD, ASD, PDA, HLHS
VSD
 Most common
 Spontaneous closure in Half of the
  patients
 M:F > 1:1
 Takes upto 4 wks to develop CHF
   ASD                          PDA
   Mostly closes                Large vessel connects
    spontaneously                 pul. Trunk with
   May develop CHF but not       descending aorta.
    in neonatal period           Persistent patency of fetal
                                  channel after birth

                                 Closure in utero may lead
                                  to fetal demise of PHT
Factors associated with PDA
    Associated with Increased
     incidence                                Associated with
    Prematurity                               Decreased
1.   45 % in BW < 1750 gms
2.   80 % in BW < 1000 gms                     incidence
    RDS and surfactant treatment
    Fluid administration: Increased      1.   Antenatal steroid
     iv fluid load in first few days of
     life > increased incidence of             administration
     PDA
    Asphyxia                             2.   IUGR
    Congenital syndromes
    High altitude                        3.   PROM
    As a part of CHD
Clinical signs and presentation of
PDA
 Murmur
 Bounding pulses and increased pulse
  pressure
 Hypotension
 Respi deterioration
Diagnosis
and Mx
   Diagnosis             Mx
   Echo                  Ventilatory support
   Radiologic signs      Fluid Restriction
                          Increase HCt
                          Indomethacin
                          Ibuprofen
                          Surgery
Cx and C/I of Indomethacin
   Cx                         C/I of indomethacin
   Renal Defects(             S. Creatinine> 1.7
    transient decrease in      Frank GI or renal
    GFR)                        Bleeding
   GI bleeding                NEC
   Platelet function          Sepsis
                               Arterial blood gas
• A blood gas measurement on an arterial sample should be obtained in any
newborn with cyanosis.
•An arterial PO2 value provides more specific data than oxygen saturation.
•Because of the increased affinity of fetal hemoglobin for oxygen, PO2 values
at a given level of oxygen saturation are often lower in newborns than adults.
•An elevated arterial PCO2 value often indicates the presence of pulmonary
disease. PCO2 may also be increased in heart failure.
•A reduced pH level raises concern about poor cardiac output. The
combination of severe hypoxemia, metabolic acidosis, and marked
hypercarbia may occur in patients with d-transposition of the great arteries
when there is inadequate mixing at the levels of the atria, ventricles, and great
vessels.
•Patients with methemoglobinemia typically have low oxygen saturation and
normal oxygen tension., the blood has a chocolate-brown color
                             Hyperoxia test
   The hyperoxia test is useful in distinguishing cardiac from pulmonary
    causes of cyanosis.

   In CHD associated with intracardiac right-to-left shunting, blood in
    the pulmonary veins is fully saturated with oxygen in ambient air.
    Administering higher concentrations of inspired oxygen increases
    the amount of dissolved oxygen but has minimal effect on oxygen
    tension levels. In contrast, patients with pulmonary disease have
    pulmonary venous desaturation. Supplemental oxygen
    administration in pulmonary disease typically increases pulmonary
    venous oxygen levels and improves systemic oxygenation.

   The preductal oxygen tension while breathing 100 percent oxygen
    concentration rarely exceeds 150 mmHg in cyanotic heart disease,
    and usually exceeds this value in pulmonary disease
Mx
   General approach — The initial approach includes cardiorespiratory support and
    monitoring. If there is respiratory compromise, an adequate airway should be
    established immediately and supportive therapy (eg, oxygen, mechanical ventilation)
    instituted as needed. Patients with hypotension or poor perfusion require
    cardiopulmonary resuscitation.
   Antibiotics — Sepsis can lead to cyanosis and left ventricular dysfunction or
    pulmonary disease. As a result, unless another specific etiology is promptly identified,
    broad spectrum antibiotics should be initiated (ampicillin and gentamicin) after
    obtaining a complete blood count, urinalysis, and blood and urine cultures.

   Prostaglandin E1 — An infant who fails the hyperoxia test and does not have
    persistent pulmonary hypertension of the newborn or a chest radiograph consistent
    with lung disease is likely to have a congenital heart defect that is dependent upon
    the ductus arteriosus for pulmonary or systemic blood flow. If metabolic acidosis is
    present or if timely echocardiography is not available, prostaglandin E1 should be
    administered until a definitive diagnosis is established. This is usually started as an
    intravenous infusion in a dose of 0.05 µg/kg per minute
   DEFINITION — Cyanosis is a bluish discoloration of the
    tissues that results when the absolute level of reduced
    hemoglobin in the capillary bed exceeds 3 g/dL [6-8].
    The appearance of cyanosis depends upon the total
    amount of reduced hemoglobin rather than the ratio of
    reduced to oxygenated hemoglobin.
   Two mechanisms result in an increased concentration of
    reduced hemoglobin in the capillary bed that in turn
    leads to cyanosis: increased oxygen extraction by the
    tissues and systemic arterial oxygen desaturation. Based
    upon these mechanisms, two types of cyanosis are
    described, peripheral and central.
   Central cyanosis — Central cyanosis, the focus of this topic review,
    is a pathologic condition caused by reduced arterial oxygen
    saturation. It involves highly vascularized tissues, such as the lips
    and mucous membranes, through which blood flow is brisk and the
    arteriovenous difference is minimal. Cardiac output typically is
    normal, and patients have warm extremities.
   Peripheral cyanosis — Patients with peripheral cyanosis have a
    normal systemic arterial oxygen saturation and increased oxygen
    extraction, resulting in a wide systemic arteriovenous oxygen
    difference. The increased extraction of oxygen results from sluggish
    movement of blood through the capillary circulation. Causes include
    vasomotor instability, vasoconstriction caused by exposure to cold,
    venous obstruction, elevated venous pressure, polycythemia, and
    low cardiac output.
   Peripheral cyanosis affects the distal extremities and circumoral or
    periorbital areas [6]. The extremities are often cool or clammy.
    Peripheral cyanosis may be associated with sepsis but is also seen
    in normal newborns, especially those with fair complexions.
   ETIOLOGY — Hypoxemia, with decreased arterial
    oxygen saturation leading to central cyanosis, results
    from the following mechanisms (show table 1) [6]:
   Right-to-left shunting at the intracardiac, great vessel, or
    intrapulmonary level
   Ventilation-perfusion mismatch
   Alveolar hypoventilation
   Hemoglobinopathy (including methemoglobinemia) that
    limits oxygen transport (show figure 3) [11]
   Diffusion impairment
   Noncardiac causes — Many noncardiac abnormalities can lead to
    cyanosis. (See "Suspected heart disease in the newborn: Criteria for
    referral").
   Pulmonary disorders are the most common causes and include structural
    abnormalities of the lung, ventilation-perfusion mismatching, congenital or
    acquired airway obstruction, pneumothorax, and hypoventilation.
   Abnormal forms of hemoglobin (eg, methemoglobin, show table 2) can
    result in cyanosis, and polycythemic infants may appear cyanotic even if
    they are adequately oxygenated. (See "Genetic disorders of hemoglobin
    oxygen affinity" and see "Neonatal polycythemia").
   Poor peripheral perfusion may result from sepsis, hypoglycemia,
    dehydration, and hypoadrenalism.
   Right-to-left shunting through the ductus arteriosus, resulting in a differential
    between SaO2 measured in the arm (preductal) and leg (postductal), can
    occur with primary or persistent pulmonary hypertension
    Cardiac causes — Cardiac causes of central cyanosis
    have been classified using different systems

    A frequently used mnemonic is the "five Ts" of cyanotic CHD:
    Transposition of the great arteries
    Tetralogy of Fallot
    Truncus arteriosus
    Total anomalous pulmonary venous connection
    Tricuspid valve abnormalities.
    A sixth "T" is often added for "tons" of other diseases, such as double outlet
     right ventricle, pulmonary atresia, multiple variations of single ventricle,
     hypoplastic left heart syndrome, complex conditions associated with
     heterotaxy syndromes, or anomalous systemic venous connection (left
     superior vena cava connected to the left atrium).
    We find that a more useful classification of cyanosis separates the defects
     into physiologic categories based upon decreased pulmonary blood flow,
     increased pulmonary blood flow, or severe heart failure.
Autosomal dominant


   Albright hereditary osteodystrophyCardiomyopathy
    Ehlers-DanlosRupture of large vessels
    Holt-OramASD, VSD
    LeopardPS, prolonged PR interval
    MarfanAortic aneurysm, AI, MVP
    Myotonic dystrophyCardiomyopathy
    NeurofibromatosisCOA, renal artery stenosis
    Osler-Weber-RenduMultiple telangiectasis, pulmonary AVF
    Treacher CollinsASD, VSD, PDA
    Tuberous sclerosisMyocardial rhabdomyoma, WPW
    NoonanPS, ASD, AS, subaortic stenosis
Autosomal recessive inheritance
   CarpenterPDA
   CockayneAtherosclerosis
   Cutis laxaPulmonary hypertension
   Cystic fibrosisCor pulmonale
   Ellis-van CreveldASDFriedreich ataxiaCardiomyopathy
   HomocystinuriaThromboses
   MPS type I H (Hurler)Coronary artery disease,
    AI,
   MIMPS type I S (Scheie)Aortic valve disease
   MPS type IV (Morquio)Aortic valve disease
   MPS type VI (Maroteaux-LamyAortic valve diseasePompe disease
    (acid maltase deficiency, GSD type 2)Cardiomyopathy
   Pseudoxanthoma elasticumCoronary artery disease, MIRefsum
    diseaseArrhythmiaSmith-Lemli-OpitzVSD,PDAThrombocytopenia
    absent radii (TAR)ASD, TOF
X-linked inheritence
   (Hunter)Coronary artery disease, valvular
    diseaseDuchenne muscular
    dystrophyCardiomyopathyEmery-Dreifuss
    muscular dystrophy
    CardiomyopathyIncontinentia
    pigmentiPDA, hypertensionFabry
    diseaseCoronary artery disease

				
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