Complications of Congenital Heart Disease

I) Cyanotic Spells

Hypercyanotic or Cyanotic spell is a pediatric emergency, which requires prompt recognition, and intervention to prevent disabling cerebro-vascular insults and to save lives. A cyanotic spell needs to be taken seriously not just because of the immediate threat but also because it indicates the need for early operation.

How to recognize a spell?
Commonly seen below two years [peaks between 2 months to 6 months]. Onset is usually spoi~taneous and unpredictable. Occurs inore often in early moi-tling,although can occur at anytime in the day. Infant cries incessantly, is irritable and often inconsolable. Tachypnea is prominent and a cardinal feature. Typically these infants have a pattei-n of deep and rapid breathing without significant subcostal recession. Cyanosis deepens as the spell progresses. Later gasping respiration and apnea ensues, which leads to limpness and ultimately anoxic seizures. Can last from minutes to hours. Auscultation reveals softening or disappearance of pulmonary ejection mui-mur. Occasional patient can have profound bradycardia.

Cardiac lesions which produce spells

• Tetralogy of fallot.
• TOF with Pulmonary atresia.
• Tricuspid atresia and PS.
• DORV with VSD and PS.
•  D-TGA or L-TGA wit11 VSD and PS.
•  Single ventricle with PS.
• Atrioventricular septa1 defect with PS.

Mechanisnz of spells
Cyanotic spells are due to an acute decsease in pulmonary blood flow, increased light to left shunt and systemic desaturation due to various causes

Infundibular spasm ndue to increased circulating catecholamines as a result of effort of feeding or crying .Activation of mechano-receptors in RV due to decrease in systemic venous return or that in LV due to decreases in pulmonary blood flow, leading to peripheral vasodilatation and fall in systemic vascular resistance producing increased right-left shunt and systemic desaturation. Same mechanism can account for occasional episodes of bradycardia [vaso-inhibitory response].Supra venbicular tachycardia as a cause of spells in pulmonary atresia.

Management of spells

• Check airway and start oxygen.
• If child is unconlfortable wit11 mask or nasal cannula, deliver oxygen via tube whose end is held $4 - 1 inch away from nose. This corresponds to delivering 80 per cent oxygen.
•  Knee-chest position.
•  Sedate child with subcutaneous morphine 0.2 mgkgldose or IIM ketamiile [3-5 n~gkgldose].
•  Obtain a reliable intl.avenous access.
• Soda-bicarbonate 1-2 m l k g given as 1:1 dilution or can be diluted in 10 ml/kg of isolyte P which is given bolus as the initial resuscitating tluid.
• Coi~ect hypovole~nia (10mVkg fluid bolus of isolyte P or dextrose nornlal saline).
• Keep the child warm.

Correct anemia by packed cell tsansfusion. Hemoglobin level < 12 g d d l meiit corection through a blood tsansfusion in children with cyanotic spells.

Start beta-blockade. Beta blockade is fairly safe unless a specific contraindication like bronchial asthma or ventricular dysfunction exists. It
should always be given with heart rate monitoring.

Medications and dosages:

• IV metoprolol0.1. ingkg, given slowly over 5 rnin.
• Can repeat every 5-nlin for a maximum of 3 doses.
• Can be followed by infusion 1-2 mcg/kg/min.
• Monitor saturation, heart rates and BP.
• Aim to keep heart rate below 100Imin.
• Other options
• l/v esmolol: 500mcg/kg over 1 min as loading dose, 50 mcg/kg/min for 4 minutes; if desaturatioi~ persists without a significant decrease in heart rate the loading dose will need to be repeated and the infusion rate can be increased in 50 mcg/kg/rnin increments until 300mcglkgmin; this infusion should be maintained at the rate that produces the desired result. Esmolol is relatively
• expensive but has the advantage of being very shol-t acting.
• propranolol [O. 1 mgkg].

If desaturation persists and there is still no significant trend towards improvement despite maximum beta blockage.

• Start vasopressoin infusion.
• Methoxamine given I/V at dose of 0.lmg-0.2 mgkg /dose or I/M (0.1- 0.4 mgkgldose).
• Phenylepherine: 5ugkg as bolus and than 1-4 ugkglmin as infusion.
•  If spells are persistent, consider paralysing the child, elective intubation and
• ventilation and plan for surgery, which can be corrective or. palliative [BT shunt].
•  If convulsions occur consider IV diazepam 0.2 m g k g or IV rnidazolam 0.1-0.2 mg /kg /dose, as slow push.

Appropriate and timely management of cyanotic spells can save lives and prevent CNS insults.

Il) Neurological Complications of Congenital Heart Disease Neurological colnplications contribute substantially to mortality and morbidity from congenital heart disease. The long-term consequences of many of these complications are often devastating. Congenital heart disease has been shown to adversely influence the neuro-developmental outconle of children.

Acute Global Ischemia

Acute global ischemia of the central nervous system result from a sudden marked reduction in oxygen supply to the central nervous system.

Acute Focal Ischemia

Focal neurological deficits or " strokes" may result in a variety of ways.1n a recent retrospective series on strokes in adults with cyanotic congenilal heart disease die occurrence of strokes best correlated with frequent phlebotomy and nlicrocytosis.

Embolization from a cardiac source occurs in patienls with congenital heart disease who have dilated andlor dysfunctional cardiac chambers. Paradoxical embolization is often difficult to document, but may be responsible for strokes in patients with congenital heart disease.

Infections of the Central Nervous System

Brain Abscess

This problem is largely confined to the developing world where it continues to be a major problem for a luge population of uncorrected cyanotic congenital heart disease and accounts substantially for the increased mortality and morbidity.Mycotic aneurysms can result from infective endocarditis. This is potelltially lethal because of a high incidence of intracranixl bleeding.