CASE PRESENTATION
13Case 3 Fallot’s Tetralogy
The primary developmental abnormality is of the pulmonary subvalvular or infundibular area leading to pulmonary stenosis (PS) and right ventricular outflow tract (RVOT) obstruction. Rarely, the pulmonary valve is absent (pulmonary atresia). The ventricular septal defect (VSD) is membranous in location. The aorta is displaced rightward and overrides the septum, the overriding aorta (OA).
Therefore, the septum is not in line with the anterior aortic wall but with the aortic valve closure point. The right ventricular hypertrophy (RVH) is secondary to RVOT obstruction. Rarely, an atrial septal defect (ASD) may be associated, in which case the constellation is designated as pentalogy of Fallot.
Figure 3.3: The four components of Fallot’s tetralogy. AO: Aorta; OA: Overriding aorta;
RA: Right atrium; LA: Left atrium; RV: Right ventricle; LV: Left ventricle PS: Pulmonary stenosis;
PA: Pulmonary artery; VSD: Ventricular septal defect; RVH: Right ventricular hypertrophy Figure 3.2: Pulmonary regurgitation
14 Section 1 Congenital Heart Diseases
In a typical unrepaired case of Fallot’s tetralogy, auscultatory findings are a loud, single S2 and a parasternal systolic murmur. The S2 is single because the P2 is muffled and the A2 is loud because the aorta is anteriorly placed. The systolic murmur originates from the subvalvular pulmonary stenosis and not from the ventricular septal defect. The classical clinical features of Fallot’s tetralogy are central cyanosis, finger clubbing, anoxic spells, growth retardation and exercise intolerance. Congestive heart failure is rare because the septal defect balances the right and left ventricular pressures. If left unrepaired, catastrophic complications in adolescence are arterial thrombo-embolism and cerebral abscess.
MANAGEMENT ISSUES
Until the 1970s and even early-1980s, surgical interventions in very early childhood were largely palliative. These shunt procedures were performed to bypass the RVOT obstruction and to enhance pulmonary blood flow. These shunts were Blalock-Taussig shunt (subclavian artery to pulmonary artery) and Waterston shunt (ascending aorta to right pulmonary artery). However, even after these procedures, patients remained symptomatic and complications occurred unabated. Nowadays, total surgical correction is undertaken to close the shunt and to enhance pulmonary blood flow. This includes patch closure of the VSD with pulmonary subvalvular muscle resection and valvotomy.
Cardiac surgeons are increasingly encountering complications of prior surgical correction, as these children survive into their teens. Complications after surgery include residual shunt, residual stenosis or, post-valvotomy pulmonary regurgitation and right ventricular enlargement as in our case. Pulmonary valve replacement with tricuspid annular repair would be the best course of action in this case.
RECENT ADVANCES
Prior cardiac surgery often distorts the anatomy of the heart to an extent that the information obtained from transthoracic echocardiography is generally skewed and inconclusive. Modern cardiac imaging techniques of computed tomography (CT) and magnetic resonance imaging (MRI) are particularly useful to evaluate postoperative patients.
Percutaneous techniques are currently being evaluated in the management of Fallot’s tetralogy. Pulmonary balloon angioplasty and artificial valve deployment by non-surgical intervention have been recently described.
C A S E
4 Ebstein’s
Anomaly
CASE PRESENTATION
A 26-year old married woman visited a cardiologist’s chamber, with the complaint of occasional fluttering sensation in the chest of 2 years duration. The episodes of palpitation were associated with some light-headedness, but she had never fainted.
Her palpitation was at times related to some emotional upset or undue physical exercise, but there was no history of exertional fatigue, chest pain or breathlessness.
There was also no history of tremor of the hands or weight loss. Her childhood had been uneventful with normal growth milestones and there was no history of cyanotic spells during sports activities. She also denied having had recurrent sore-throat, joint pains or any prolonged febrile illness during her school days.
On examination, the patient was comfortable, relaxed and not dyspneic. There was no tremor of the fingers, visible goiter or eye-signs of Grave’s disease. The JVP was raised 5 cm above the angle of Louis and showed large v waves with a prominent y descent. The pulse was regular, fair in volume, at a rate of 84 beats/min. and the BP was 130/80 mm Hg. On examining the abdomen, there were visible epigastric pulsations, with the liver edge 6 cm below the right costal margin and pulsatile; no ascites was demonstrable. The apex beat was normal in nature and location but a left parasternal heave was palpated. The S1 and S2 were both split with wide splitting of S2 appreciated during inspiration. No S3 or S4 gallop sound was heard. A pansystolic murmur was audible at the lower end of the left sternal edge. Breathing was vesicular and no rhonchi or crepts were heard over the lung fields.
CLINICAL DISCUSSION
From the history and physical examination, this patient had paroxysmal tachycardia with clinical signs of tricuspid valve regurgitation. ECG showed tall P waves (P. pulmonale) with normal P-R interval and right bundle branch block (RBBB). X-ray chest finding was an enlarged cardiac silhouette, more so towards the right of the midline. ECHO revealed normal sized left ventricle with normal ejection fraction. The mitral and aortic valves were normal and the left atrium was not dilated. There was no echo drop-out in the region of either septum. However, the right atrium was markedly enlarged and the right ventricle was dilated as well as hyperkinetic. The tricuspid valve was displaced downwards into the right ventricle, with distal attachment of the septal tricuspid leaflet which showed
16 Section 1 Congenital Heart Diseases
exaggerated excursion. On colour flow mapping, a regurgitant jet was seen in the right atrium. These findings are consistent with the diagnosis of Ebstein’s anomaly.
In a young woman, history of episodic palpitation raises several clinical possibilities. Anxiety neurosis, panic attacks and paroxysmal supraventricular tachycardia are usual causes but in these, the heart is structurally normal.
Perimenopausal symptoms in women include palpitation but our patient was young. Thyrotoxicosis is a possibility but our patient had no goiter, tremor or eye-signs of Grave’s disease. Pre-excitation syndrome (WPW syndrome) may be responsible for paroxysmal tachyarrhythmia but the ECG did not show short P-R interval or delta waves on the QRS complex. Mitral valve prolapse (MVP) and atrial septal defect (ASD) are structural cardiac abnormalities that are responsible for tachyarrhythmias. However, in our case the mitral valve was normal and there was no septal defect.
Ebstein’s anomaly is an uncommon congenital acyanotic heart disease characterized by abnormal tricuspid valve architecture, tricuspid regurgitation and association with paroxysmal supraventricular tachyarrhythmias. The physical examination of the patient and interpretation of simple cardiac investigations is a good exercise in bed-side clinical cardiology. A raised JVP with large v waves and prominent y descent are characteristic of tricuspid regurgitation into the right atrium (Fig. 4.1). So is an enlarged and pulsatile liver on abdominal examination.
A sustained left parasternal heave is indicative of right ventricular volume overload.
Figure 4.1: Tricuspid regurgitation
The S1 is split because of delayed tricuspid valve closure (T1) due to right bundle branch block (RBBB) as well as the wide excursion of the septal tricuspid leaflet. The S2 is widely split due to delayed pulmonary closure (P2) because of the RBBB. Sometimes, the S2 is single because of soft P2 due to low pulmonary ejection volume. Rarely, the S2 is paradoxically split because of pre-excitation of the right ventricle caused by WPW syndrome Type B. The pansystolic murmur of tricuspid regurgitation is best audible over the lower left parasternal area and does not radiate towards the axilla or the base of the heart. Like all right-sided murmurs, it
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