Ebstein ’ s Anomaly : Anesthetic Management at shahid Gangalal National Heart Centre

During the last eight years, 34% of the cases have been congenital; out of which only 0.7% have been Ebstein’s Anomaly. In the literature they have mentioned that the male and female ratio is 1:1, but there are more female than male in our series, 15:3.


INTRODUCTION
Ebstein anomaly is a rare congenital heart disease having an incidence of 0.3-0.6% of all congenital heart disease.Both sexes are equally affected.Lithium exposure during pregnancy can cause Ebstein's anomaly.
During the period of eight years we did 6035 total cardiac operation in our center which includes congenital, valve surgery and vascular surgery.In the first year it was over 200 cases; however this year, more that 1200 cases have been done.All cases have undergone general anesthesia.
Out of the 6035 total cases 34%, 0.73% (15 cases) were Ebstein's anomaly, among them three were male and twelve female.The age distribution ranged from 6 years to 30 years.There have been no Ebstein's cases under the age of 4 years in our series.

HISTORY
Dr. Wihelm Ebstein, physician in Poland described the clinical finding of an adolescent man who died of cyanotic congenital heart disease in 1866.He correlated his postmortem finding with the notes given by his colleague.In 1949, first Ebstein case was diagnosed in a living person.The first surgery was done by Wright and his colleague in 1954 and it was direct closure of foramen ovale.
Hunter and his friend repairedthe tricuspid valve in 1958.In 1963, Burnard and Schrise replaced the tricuspid valve.This was the mechanical prosthetic valve.
Im Mayo clinic, 1972, they did the plication of the arterialized portion of the right ventricle, tricuspid anuloplasty and reduction atrioplasty of the right atrium which was better than valve replacement in many aspects.Echocardiography is the key diagnostic tool for the diagnosis of the Ebstein's anomaly.It can provide anatomical as well as physiological information about the heart.

Cardiac Catheterization
Cardiac catheterization is usually not done because of the risk of perforation, bit if needed it is done where the right to left shunt can be measured but cardiac catheterization is more importantly used for the ablation of abnormal conducting system.

Pre-operative management
Sedation, paralysis and intubation are needed if the patient is very sick.Hyper ventilation is needed to reduce the pulmonary vascular resistance but care must be taken that the endo-tracheal tube should be watched out for.
In the neonate, in order to open the ductus arterious, to increase the pulmonary blood flow, prostaglandin E1 infusion is necessary.
Patients may have pulmonary hypertension and metabolic acidosis, thus measures should be taken to reduce pulmonary hypertension by oxygenation, vasodilator like GTN or nitric oxide, alpha-adrenergic agonist.Correction of metabolic acidosis is important because it can improve the myocardial function and reduce the pulmonary vascular resistance.Patient may need appropriate inotropic support as they have a low cardiac output, however epinephrine should be avoided since it can raise the pulmonary vascular resistance in high dose.Fluid administration should be minimized in view of the fact that it can increase the tricuspid regurgitation hence the central venous pressure should be less than 10 mm Hg.

Precautions
There is a communication between left and right side of the heart.There is absolute necessity of an IV line that is free of air bubble.While giving drug precaution should be taken against air being pushed in.
Endo tracheal tube should be kept in a right position because one lung vantilation can produce barotrauma and hypoxia.
During Central Venous Catheter Placement, extra precaution must be taken because the patient can develop arrhythmia and perforation of right atrium.

Monitoring system during anesthesia
The following monitoring system is required for the anesthetic management- extra cardiac defect before anesthetic management.It is also essential to identify the drugs and their pharmacology, which maintains the pulmonary and systemic pressure.It should be kept in mind that patients are prone to develop arrhythmia, especially arterial type.
Deformed tricuspid valve and increased pulmonary vascular resistance causes right to left shunt at arterial and ventricular level and there is a high chance of right ventricular failure while patients come up from cardio pulmonary bypass or immediate post operative period.

Induction and maintenance of anesthesia
Recent data from several investigators suggest in general that a number of induction techniques such as IM and IV ketamine, IV narcotics, and halothane with or without nitrous oxide can be used safely in the management of a child with cyanotic CHD.Unlike in adult patients, both nitrous oxide and ketamine have been shown to have no worsening effects on the pulmonary vasculature of children with CHD.* IV ketamine, 1-2 mg/kg with 100% oxygenation and paralyzed with vecuronium bromide, endotracheal tube of appropriate size sucured and ventilated with oxygen; anesthesia was maintained with IV infusion of propofol, fentanyl and intermittent bolus dose of vecuronium.
Dipamine 5-10 micrograms/kg/min, milrinone 0.5-0.7 microgram/kg/min and noradrenaline 0.05-0.1 microgram/kg/ min was started after rewarming.With hemoglobin, electrolyte, blood sugar, blood gas, temperature, and blood pressure and rate rhythm of the heart is normal, Cardio pulmonary bypass was terminated Post-operative problems: i.Low cardiac outputtricuspid valve regurgitation leads to right ventricular dilation which obstructs the filling of left ventricle and therefore reduces cardiac output.There maybe intracardiac shunt, which also decreases the cardiac output, leading to ineffective circulation and metabolic acidosis.Inotropic support with appropriate volume is the goal of therapy.
ii. Pulmonary insufficiencyin Ebstein's anomaly, lung hyperplasia is almost always there, so it can complicate the pulmonary insufficiency.Care should always be taken to differenciate it from hyper inflation of the chest.
iii.Residual tricuspid regurgitationit is managed by appropriate inotropic support with after load reduction and meticulous volume replacement.iv.Postoperative dysrrhythmiasdysrrhythmias can occur in any type of cardiac operation.They have intrinsic abnormalities of conduction system they can produce any kind of arrhythmias.They can produce heart block if the tricuspid valve is replaced.Epicardial artial and ventricular pacing wire is very important.

CONCLUSION
Ebstein's anomaly is a rare complex congenital heart disease which consists of less than 1% of all congenital heart diseases.No two Ebstein are identical, each has its own presentation, morbidity, mortality, and natural history.

Figure 4 :
Figure 4: Normal and Heart with Ebstein's Anomaly

Figure 5 :
Figure 5: X-ray chest of Ebstein's anomaly Electrocardiography About 50% of individuals with Ebstein's anomaly have evidence of Wolff-Parkinson-White syndrome, secondary to the atrialized right ventricular tissue.Other abnormalities that can be seen on the ECG include (1) signs of right arterial enlargement or tall and broad 'Himalayan' P waves, (2) first degree atrioventricular block manifesting as a prolonged PR-interval, (3) low amplitude QRS complexes in the right precordial leads, (4) right bundle branch block, (5) T wave inversion in V1-V4 and Q waves in V1-V4 and II, III and aVF.

Figure 6 :
Figure 6: Echovardiograph of Ebstein's anomaly and electrolytes Anesthetic Management It is important to understand the anatomy and Pathophysiology of Ebstein's Anomaly and associated intra and Nepalese Heart Journal 2009; 6(1): 49-52