Comments: CCTGA is an uncommon congenital cardiac anomaly. It accounts for less than 0.5% of all congenital heart disease. The most common associated defects are VSD (60%–80%), and pulmonary stenosis, or, more appropriately, LVOT obstruction (30%–50%). Tricuspid valve abnormalities are also common (14%–56%). Ebstein malformation, dysplasia of the valve, abnormalities of the subvalve apparatus, and straddling and overriding with respect to the VSD have all been reported.

Neither her ACHD nor anticoagulation is an absolute contraindication to pregnancy. The outcomes of pregnancy in 22 women with CCTGA have been reported. There were a total of 60 pregnancies resulting in 50 live births, with no pregnancy-related deaths, and none of the live infants was diagnosed with congenital heart disease.

Patients with CCTGA are at high risk of developing AV block whether operated on or not. The sinus node is normally positioned, but the AV conduction tissue is grossly abnormal. At 20-year follow-up, 45% of unoperated patients will have developed third-degree heart block, slightly higher than the suggested figure of 30%. Subsequently, it has been reported that spontaneous complete heart block in this population occurs at a rate of about 2% per year. Surgically induced heart block is still common. The anatomy of the AV node was described in 1973 by Bob Anderson. While this knowledge transformed the incidence of complete heart block in those undergoing surgery, it remains a risk.

Several authors have shown that the regular AV node located at the apex of the triangle of Koch rarely gives origin to a penetrating AV conduction bundle. Instead, there is an anterior course of an anomalous AV node and penetrating bundle, which is commonly located beneath the opening of the right atrial appendage at the lateral margin of the area of pulmonary-to-mitral valve continuity. The elongated bundle has a superficial course underneath the right anterior facing leaflet of the pulmonary valve and descends for some distance before branching. Histological study often reveals pathologic changes within the bundle, such as fibrosis, even in the absence of abnormal conduction.

The development of new tricuspid regurgitation within 2 years of operation is not surprising in CCTGA after a conventional (classic) repair. Voskuil and colleagues studied the postoperative outcomes of 73 patients with CCTGA and found that RV function and tricuspid valve function both deteriorated with age. These complications developed more frequently after conventional intracardiac operations compared with patients undergoing palliative intervention or no surgery at all. Indeed, several studies have shown that RV dysfunction and tricuspid regurgitation both deteriorate more frequently following intracardiac operation than in patients either unoperated or treated with closed heart procedures.

Tricuspid valve function depends on the loading conditions of the ventricles and the secondary effects on septal geometry. Interventions that increase RV volume or decrease LV pressure induce and worsen tricuspid regurgitation. Graham and colleagues reviewed 182 adult patients from 19 institutions. The strongest risk factors for clinical congestive heart failure and RV dysfunction included tricuspid valve surgery, important tricuspid regurgitation, history of any open-heart surgery, and pacemaker therapy.

Atrial arrhythmia is common. Connelly and associates reported outcomes in 52 patients with CCTGA. During a period of approximately 10 years of follow-up, 25% died and 36% of the survivors had documented atrial fibrillation, atrial flutter, or supraventricular tachycardia.

Comments: Patients with all types of mechanical valves require antithrombotic prophylaxis. Bjork and Iienze in 1975 reported that among patients (without complex ACHD) with the Bjork-Shiley spherical disk valves who received no prophylaxis or prophylaxis with aspirin alone, thromboemboli occurred in 23% per year.

In patients who have mechanical valves and additional risk factors such as atrial fibrillation, myocardial infarction, left atrial enlargement, endocardial damage, and low ejection fraction, the American College of Chest Physicians recommended adding low-dose aspirin, 75 to 100 mg/day.

Comments: Her clinical examination is in keeping with her underlying diagnosis and good clinical status. The finding of a right-sided apical impulse is seen in about 20% of patients with CCTGA. The atrial situs is inversus (mirror image) in 5% to 8% of patients, and solitus (usual) in 92% to 95%.

At the time of her initial VSD closure and conduit placement, the surgeon elected to expose the heart using two thoracotomy incisions because of, as he described, “an awkward anatomy with situs inversus.”

The short ejection systolic murmer implies little LVOT/conduit obstruction.

The absence of a diastolic murmur argues against significant conduit valve regurgitation, especially since the conduit is substernal.

The liver in situs inversus will be left-sided, so one must palpate in the correct area.