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Congenital heart diseases

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أستاذ المادة عبد المهدي عبد الرضا حسن الشحماني       03/11/2017 05:29:47
Congenital heart diseases

د. عبد المهدي عبد الرضا حسن
Ph.D, Pediatric & psychiatric Mental Health Nursing


Definition and introduction of congenital heart diseases (CHD):
? It includes primarily anatomic abnormalities present at birth that results in abnormal cardiac functions.
? The newborn’s heart begins to beat at 28 days of gestation
? The heart is completely developed on the 9th week of intrauterine life

Incidence:

? 4 – 10/100 live births
? It is the majority cause of death during the 1st year of life after prematurity
? Sexes are affected differently depending on the defect
? It is more likely to be with other congenital anomalies e.g. T.E fistula, Renal agenecies and diaphragmatic hernia.

Etiology:

? Most of them are unknown
? Factors associated with increased incidence:
– Prenatal factors:
• Maternal rubella
• Radiation
• Alcoholism
• age >40 yrs
• Insulin dependent diabetes
• Fetal intra uterine cardiac viral disease

– Genetic factors: although the influence is multifactorial there is high risk of CHD in children who have:
• a sibling with a heart defect
• a parent with CHD
• chromosomal aberration e.g. Down’s syndrome
• Born with other congenital anomalies
? After birth failure of obliteration of ductus arteriosus or foramen ovali

Altered hemodynamic:
? Blood flows from high pressure to area of lower pressure and with lower resistance, in response to the pumping action of the heart.
? The higher the pressure gradient the greater the rate of flow
? The higher the resistance the less the rate of flow
? Normally the pressure in the Rt side is lower than the Lt side of the heart


5. The resistance in the pulmonary circulation and vessels entering or leaving these chambers have corresponding pressure.

6. So if there is septal defect, blood will flow from Lt to Rt known as left to right shunt, and no desaturated blood flows directly into the Lt side of the heart so it is acyanotic defect

Cyanotic defects are due to:

? Change in the pressure causing blood to flow through Rt - to- Lt Shunt.
? Due to increased pulmonary flow through the pulmonary vascular resistance

? Or obstruction to the blood flow through the pulmonary valve and aorta
? Or due to mixing of the blood between pulmonary and systemic circulation e.g. Truncus arteriosus (the pulmonary artery and the aorta are one single vessel that overrides both ventricles

Classification and clinical consequences:

? Depending on the severity of the cardiac defect and the altered hemodynamics two principal clinical consequences can occur:
1st Consequence is Congestive heart failure
2nd Consequence is Hypoxemia

1st Consequence Congestive heart failure:
? Occurs mostly in infants.
? It is inability of the heart to pump adequate blood to the systemic circulation to meet the metabolic demands of the body
? It is a symptom caused by cardiac defect not a disease in itself, it is due to ++ work load on normal myocardium

Pathophysiology of congestive heart failure:

? 1st category:
Rt sided failure; the Rt ventricle is unable to pump blood to pulmonary artery resulting in increase in the pressure in the Rt atrium and systemic venous circulations leading to liver and spleen enlargement and occasionally edema.


? 2nd category
Lt sided failure, the left ventricle is unable to pump blood into the systemic circulation leading to increased pressure in the Lt atrium and pulmonary veins.

The lungs become congested leading to increased pulmonary pressure and pulmonary edema.

Congestive heart failure leads to:
? Cardiac muscles damage
? Decrease the cardiac output
? Decrease the flow of blood to the kidneys
? Increase the re-absorption of Na and water and increase blood volume
? Increase systemic congestion
? Distention in neck veins and peripheral veins
? Edema and hepatomegaly
? Forehead sweating due to sympathetic response

Diagnostic evaluation
Clinical manifestations of congestive heart failure:
? Impaired Myocardial Function:
? Tachycardia (occurs early)
? Sweating
? Decreased urine output
? Weakness
? Fatigue
? Restlessness
? Anorexia


? Pale cool extremities
? Weak peripheral pulses Low blood pressure
? Gallop Rhythm heart beats
? Cardiomegaly
? Pulmonary Congestion:
? Tachypnea
? Dyspnea
? Retraction of ICS in infants Flaring nares
? Exercise intolerance
? Orthopnea


? Cough and hoarseness of voice Cyanosis
? Wheezing
? Grunting
? Systemic Venous Congestion:
• Weight gain (due to edema)
• Hepatomegaly
• Peripheral edema especially periorbital area
• Ascites
• Neck vein distension (children)

Therapeutic management
Goals:
? Improve cardiac function
? Remove accumulated fluid and Na
? Decrease cardiac demands
? Improve tissue oxygenation and decrease O2 consumption

Myocardial efficiency improved by giving:
Digitalis glycosides (Lanoxin /Digoxin)
? Increase cardiac output
? Decrease heart size
? Decrease venous pressure
? Decrease edema
? Regulate heart rate
Nursing alert
Digoxin is not given if:
? The apical heart rate in infants is <90 -110
? The apical heart rate in young children is <70

Angiotensin-converting enzyme (Captopril/capotin)

? Inhibit the normal function of rennin angiotensin in the kidney and vasodilatation occur, decrease pulmonary and systemic vascular resistance and decrease B/P decrease after load


? Remove accumulated fluid and Na:
– Diuretics. frusamide (Lasix). Thiazide and Spironolactone.
– Possible restriction of fluids and decrease Na
– Observe fluid intake and out put and Signs of dehydration
– Potassium supplement, because Diuretics increase potassium loss


? Decrease cardiac demand:
– Decrease physical activities, by bed rest, observe body temp.
– Treat any infections
– Improve breathing ; semi sitting position and sedate irritable children
? Increase tissue oxygenation and decrease O2 consumption by applying the mentioned measures and giving humidified cool O2

2nd Consequence Hypoxemia

Hypoxia:
? Reduction in tissue oxygenation that results from ?oxygen saturation and PaO2 and results in impaired cellular process
Cyanosis:
? Blue discoloration of mucus membrane, skin nail beds of the child with reduced O2 saturation, results from the presence of deoxygenated hemoglobin in a concentration of 5g/dl of blood or more.

Clinical manifestations of Hypoxemia :
? Polycythemia
? Clubbing of the finger
? Hypercyanotic spells

Hypercyanotic spells

? Hypercyanotic spells:
– Cyanosis and hyperapneia
– ?Rt -to-Lt Shunt.
– Rare < 2 months of age
– More common in >1year of age increase in the morning and during feeding, crying and defecation
– Possible consequences :
? CVA
? Brain abscess
? ?Development


Congenital Heart Diseases
TYPES OF DEFECTS and Classification

1st Acyanotic 2nd Cyanotic

++Pulmonary Obstruction to --Pulmonary Mixed
blood flow blood flow flow flow

? ? ? ?
- ASD - Tetralogy TPOGA
TPOGV
VSD - Coarctation of of Fallots Truncus
the aorta
arteriosis.
PDA - Tricuspid
Hypoplastic
Artesia
Pulmonic stenosis Lt Heart
Aortic stenosis syndrome


Acyanotic Defects:
? Lt – to – Rt shunting through an abnormal opening or obstructive lesions lead to decrease blood flow to various parts of the body.
? The most common clinical manifestation is heart failure. Some of them may be asymptomatic. E.g. Patent ductus arteriosus

Patent ductus arteriosus:

? Is when the fetal ductus artery connecting the aorta and the pulmonary artery fails to close within few weeks after birth, so the blood flows from the high pressure of the aorta to the lower pressure of the pulmonary artery (Lt – to –Rt shunt
Incidence:
? It is most common cardiac anomaly
? The ratio is: 2 ?: 1?


Clinical Manifestations:

? With or without congestive heart failure
? Machinery - like murmur at 2nd Lt ICS
? Widened pulse pressure and bounding like pulses resulting from runoff of blood from aorta to pulmonary artery
? Risk of bacterial endocarditis and pulmonary vascular obstructive disease in later life from chronic excessive pulmonary blood flow may occur


Medical Management:

Endomethacin (Prostaglandin inhibitor) is successful in helping in the closing of the PDA in newborns
? Closure with placement of an occluding device during cardiac cath is done in some institutions
? Prognosis is good with < 1% mortality
Surgical Management:
? Ligation with, or with out, division of the patent vessel.
Prognosis is good with 1% mortality

Atrial Septal defect (ASD)
An abnormal opening between atria
With a Lt - to – Rt Shunt

Clinical Manifestations:
? Characteristic murmur
? Pt is at risk for atrial dysrythmia ( may be due to atrial enlargement and stretching of conduction fibers) and pulmonary vascular obstructive disease, later in life due to ? pulmonary blood flow

Management:
? Surgical correction:
? Closure of moderate – large defects
? Open repair with cardiopulmonary bypass
Prognosis:
? Very low mortality, <1%


Ventriculo Septal Defect (VSD):

It is an abnormal opening between right and left ventricles, may vary in size ; small pinhole to the absence of the septum, resulting in common ventricle. Frequently associated with other defects
? Lt –to – Rt Shunt
Clinical Manifestations:
? Congestive heart failure is common
? Characteristic murmur
? High risk of bacterial endocarditis and pulmonary vascular obstruction disease

Ventricular Septal Defect (VSD)

? {Eisenmenger Syndrome }: If pulmonary resistance increase and Lt – to – Rt Shunt is even further reduced and a Rt – to – Lt Shunt results, the unoxygenated blood crosses the VSD to the Lt ventricle and enters the systemic circulation. Combination of pulmonary hyper tension and bidirectional or reversed shunting through {VSD, ASD, or PDA}

Management:
Surgical correction
? Palliative: Pulmonary banding on symptomatic infants
? Complete repair:
? Small defect by purse-string
? Large defect require knitted Dacron patch sewn over the opening
Both (a and b) need cardiopulmonary bypass

Prognosis:
? Risk depend on location of the defect
? < 5% - 20% mortality also depends on other anomalies in the heart

Pulmonary stenosis (PS)
? It is narrowing at the entrance of the pulmonary artery, resistance to blood flow cause RT ventricular hyper atrophy and decrease pulmonary flow
Clinical Manifestations:
? Mild cyanosis or cardiac failure
? Newborns with severe narrowing will be cyanotic
? Characteristic murmur
? Cardiomegally is evident in chest X-ray
? ? Risk of Bacterial Endo Carditis with progressive narrowing lead to increase symptoms

Pulmonary stenosis
Management:

• Surgical correction
– Infants: Transventricular valvotomy Brock procedure
– Children: Valvotomy with cardiopulmonary bypass

• Nonsurgical treatment:
– Balloon angioplasty in the cardiac cath to dilate the valve
Prognosis: < 2% mortality

Aortic stenosis AS
? There is narrowing or stricture of aortic valve leading to resistance of blood flow in the Lt Ventricle, decrease cardiac output. Lt ventricular hypertrophy and pulmonary vascular congestion.
Clinical Manifestations:
? Infants with severe defects:
– Decreased cardiac output and faint pulses
– Low blood pressure and tachycardia
– Poor feeding


? Children:
– Signs of exercise intolerance
– Chest pain
– Dizziness when standing for long periods
– Characteristic murmur
– Risk for bacterial endocarditis
– Coronary insufficiency
– Ventricular dysfunction

Aortic stenosis Management

? Surgical correction:
- Commissurotomy
- Patch for extensive narrowing
? Nonsurgical correction:
- Dilatation of narrowed valve with balloon angioplasty in the cath lab
? Prognosis:
? Newborn critical conditions mortality >20%
? Older children elective valvotomy has lower risk
? Recurrence is possible which will need valve replacement

Coarctation of the aorta (COA)
? There is localized narrowing near the insertion of ductus arteriosus resulting in:
Increased pressure in proximal structures to the defect (Head and upper extremities)
Decreased pressure distal to obstruction
(body and lower extremities)

Clinical manifestations:
? High B/P and bounding pulses in arms
? Weak or absent femoral pulses
? Cool lower extremities with low B/P
? Signs of congestive heart failure in infants
? Older children may experience dizziness, headaches, fainting and epistaxis due to high B/P
? Risk of B/P rupture of the aorta, aortic aneurism or stroke


Management

Surgical correction:
- Resection of narrowed portion and end - to - end anastomosis or graft replacement
Prognosis: < 5% in isolated coarctation and high risk in infants and other complex cardiac defects.
? Recurrence is possible

Major Cyanotic Defects
Cyanotic defects result from:
• Obstruction of blood flow to the lungs
• And Mixing of desaturated blue venus blood with fully saturated red arterial blood within the chambers of the heart

Tetralogy of Fallots (TOF)
? It is the most common cyanotic congenital heart disease, the defects include:
• Ventricular Septal defect
• Pulmonary stenosis
• Overriding of the Aorta
• Rt ventricular hyper atrophy

Clinical Manifestations:
? In Infants:
• Some are acutely cyanosed at birth, others have mild cyanosis that progresses over the 1st year as the pulmonary stenosis worsen
• Acute episodes of cyanosis and hypoxia (blue spells) usually during crying or after feeding

? In Children:
• With ++ cyanosis ±clubbing of fingers
• Squatting
• Poor growth
• Patients are at risk of emboli, C.V disease,Brain abscess, Seizures and loss of consciousness, or sudden death following an anoxic spell.

Management:
• Surgical correction:
• Palliative: To bring back flow to lungs, to create an artificial connection between the pulmonary and systemic circulation
• Corrective: Closure of VSD - Pulmonic Valvotomy - Patch enlargement of Rt Ventricular out flow tract below the pulmonary valve
Prognosis:
? Operative mortality about 5 – 10%

Transposition of Great Arteries or Vessels (TGA or TGV)

? Males are affected more than females
? Pulmonary artery leaves the Lt ventricle
? Aorta exits from the Rt ventricle
? With no communication between systemic and pulmonary circulation
? Associated defects such as Septal defects or patent ductus arteriosus permits blood to enter the systemic circulation and or pulmonary circulation for mixing of saturated and nonsaturated blood

Clinical manifestations: Depend on other defects

? If minimum communication cyanosis is ? and the infant will be depressed at birth
? If communication is good congestive heart failure is more common and less severe cyanosis
? Heart sounds vary according to defects
? Cardiomegally occur after few weeks of life

Management:
Surgical Palliative treatment (To provide intracardiac mixing):
? Administration of IV prostaglandin E1 to keep the ductus arteriosus open to temporary increase in blood mixing and provide O2 saturation of 75% or to maintain cardiac output.
? Rashkin procedure: Enlarge septal defect
Complete repair:
? Switching the great vessels to their correct anatomic position.
Prognosis: Operative mortality about 5 – 10%


المادة المعروضة اعلاه هي مدخل الى المحاضرة المرفوعة بواسطة استاذ(ة) المادة . وقد تبدو لك غير متكاملة . حيث يضع استاذ المادة في بعض الاحيان فقط الجزء الاول من المحاضرة من اجل الاطلاع على ما ستقوم بتحميله لاحقا . في نظام التعليم الالكتروني نوفر هذه الخدمة لكي نبقيك على اطلاع حول محتوى الملف الذي ستقوم بتحميله .