Congenital Heart Disease: Recognition & Early Diagnosis for Pediatricians

By Maitri

Congenital Heart Disease: Recognition & Early Diagnosis

By : DR MAITRI CHAUDHURI

Background:

The incidence of Congenital Heart Disease (CHD) is 4-8/1000 live births while the incidence of critical heart disease in children is 3/1000 live births. If we extrapolate these values to the current Indian annual birth rate , it is immediately obvious that we are sitting at the “Tip of An Iceberg”. The challenge is to recognize and identify these babies at the earliest.

Recognition of Congenital Heart disease:

The manifestations of CHD are subtle and also different among neonates, infants and children. Also many of these presentations can be picked up by an alert pediatrician and also sometimes these features might overlap with those of non cardiac diseases. I wish to tabulate the “Danger Signs” for quick recognition. I call it the ASK, LOOK & LISTEN approach.

ASK

PREGNANCY & DELIVERY

1. Maternal infections (Rubella), Maternal drugs(Lithium, OCP, Anti epileptics etc) , Gestational Diabetes, Hypothyroid, SLE

2. Maternal Smoking (including Passive), Alcohol

3. Birth Weight, Prematurity, Birth Asphyxia

4. ‘Test Tube’ Babies, Repeated Abortions, Child Loss

NEONATAL PERIOD

1.   CENTRAL CYANOSIS(Sats <90%), Positive Hyperoxia Test
2.   Difficult/ fast Breathing (Respiratory Rate Persistently More than 60/min)
3. Murmur
4.   Poor Weight Gain
5.   Evidence of Genetic Syndromes(Down’s etc)
6.   Other Major Malformations like Tracheo-esophageal Fistula, Anorectal malformations etc

OLDER CHILDREN

1.   Repeated Chest Infections(>2 in six months or >3 in one year)
2.   Fast Breathing / Difficult breathing
3.   Sweating of Forehead
4.   Central Cyanosis , Cyanotic Spell
5.   Poor Weight Gain (<5^th Percentile For Age)
6.   Delayed development(delay in sitting/standing/ walking)
7.   Easily gets tired than playmates
8.   Detection of Murmur
9.   Hypertension
10. Unexplained Chest Pain, Syncope, Palpitations
11. Fever and migratory joint pain, joint swelling esp. beyond 5yrs of age
12. Positive Family History For Heart Disease, Sudden Death in Young

LOOK

1.   Heart Rate- Inappropriately Low or High
2.   Pulses in all four limbs – Absent Femoral Pulses indicates Aortic Arch Anomaly
3.   Saturation: Persistent Cyanosis Not responding to Oxygen Means Cyanotic Heart Disease
4.   Respiratory Rate and Pattern
5.   Mottling of Body and Cold Peripheries
6.   Blood Pressure in All Four Limbs
7.   Hyper dynamic Precordium, Visible Cardiac Pulsations
8.   Soft, Tender Hepatomegaly

HEAR

1. Abnormal Heart Sounds (Focus on S2 – Wide fixed split or Single S2 or very loud P2 suggest Significant Heart Disease)
2. S3 Gallop/ S4/ Pericardial Rub/ Valve Click

3. Murmurs

– Any Diastolic Murmur
– Systolic Murmur ? Grade III in Intensity

4. Abdominal or Carotid Bruit
5. Chest – Crepitations/ decreased air entry

STEP II

FIRST LINE INVESTIGATIONS:

1. Electrocardiogram (ECG) : Records the electrical activity in the heart, pacemaker function, arrhythmias, cardiac axis, ischemia-infarction, chamber enlargements. Miscellaneous conditions like dyselectrolytemias, pericardial effusion, hypothyroidism etc can be indirectly assessed.

2. Chest X Ray (CXR): Extremely useful in understanding cardiac enlargement, cardiac contours, pulmonary arterial and pulmonary venous hypertension, aortic arch sidedness, lung parenchyma, pleural effusion, pneumothorax and abdominal situs (relative position of liver and stomach bubble).

3. Echocardiogram: Echo is an ultrasound of heart where two dimensional information is combined with colour flow imaging and Doppler. Recent machines also have three dimensional and Tissue Doppler Imaging. The basic points to look for in a congenital echo are:

a) Cardiac Situs & Cardiac Axis

b) Arrangement of Right Atrium (RA), Left Atrium (LA), Inter-atrial Septum (IAS), Systemic and Pulmonary Veins

c) Arrangement of Right Ventricle (RV), Left Ventricle (LV), Inter-ventricular Septum (IVS)

d) Cardiac valves- Mitral, Tricuspid, Aortic and Pulmonary

e ) Great Arteries- Aorta , Pulmonary Artery (PA) and PDA

f) Aortic arch-Coarctation, Interruption, Aneurysm etc

g) Pulmonary arterial Pressures

h) Cardiac dimensions and functions

i) Pericardial effusion, Vegetations, Cardiac clots

Bedside echocardiography has revolutionized pediatric cardiology. A number of therapeutic procedures like balloon atrial septostomy in newborns, pericardial fluid tapping in cardiac tamponade can be done in ICU with the help of an echo machine.

SECOND LINE INVESTIGATIONS:

CARDIAC CATHERISATION & ANGIOGRAPHY: It is an inpatient procedure where under ketamine- midazolam sedation or general anesthesia, direct pressure recording catheters are placed inside the heart chambers and intracardiac pressures, oxygen saturations, cardiac output, valve areas are measured. During angiography, radioactive contrast is injected via cardiac catheters and information about valve stenosis, shunts, regurgitation etc obtained.
CT Angiogram: It is an alternative modality where radioactive contrasts are injected via peripheral vein through a 22G IV cannula and focused CT is done of pulmonary artery, aortic arch etc. The disadvantage is this that intracardiac pressures cannot be recorded.
Cardiac MRI: This is a noninvasive test and also there is no risk of radiation. Both angiographic and hemodynamic information can be obtained. However, pediatric cardiac MRI is not yet available in India.
Holter Monitoring: It is a 24 hour ambulatory ECG monitoring especially useful in situations of inappropriate bradycardia, tachycardia, arrhythmias etc. Often used in pediatric patients where baseline ECG is abnormal or there is unexplained syncope.
Tread Mill Test (TMT): Although very commonly used in adult coronary heart disease, the use of TMT in children is restricted to demonstration of occult arrhythmias or postoperative children to assess the functional capacity. In children, modified Bruce protocol is used and continuous ECG and BP monitoring is done. In many places a lung function test is done before starting TMT.

CONCLUSIONS

Clinical examination including ECG and chest x-ray help answer the important question “Does the patient have CHD?”. Once CHD is suspected it is often vital to establish an accurate and complete diagnosis. This is usually achieved through detailed and systematic echocardiography. Other investigative modalities such as cardiac catheterization and cine-angiography and rarely, cardiac MRI may be used in specific situations. Most of the congenital heart diseases are absolutely treatable today. However, we miss many patients because we are not aware. The results for heart surgery in newborns and small children are excellent in the current era. So there is no point in waiting and watching. Pediatricians form the first line of pillar and on minimal doubt, a pediatric cardiologist should be called. Today with availability of portable echo machines, we should be able to reduce the incidence of CHD definitely.

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