Comments: BT and other systemic-to-pulmonary shunts are used to increase pulmonary blood flow in patients with cyanotic ACHD. They are used much less often now than in previous decades.

There are several modifications of the concept generally referred to as the Fontan operation. In this patient, an atriopulmonary Fontan operation was performed, that is, the right atrium was connected to the pulmonary arteries. Contemporary approaches include variations of the total cavopulmonary connection with a “lateral tunnel” in the RA connecting the IVC with the pulmonary arteries and an extracardiac conduit leading the IVC venous return to the pulmonary arteries. In both these latter situations, SVC return is also to the pulmonary arteries via a bidirectional Glenn anastomosis.

“Silent” pulmonary emboli are relatively common in patients with a Fontan circulation and may be easily overlooked. Though this serves as an additional argument for anticoagulation in Fontan patients, there are presently no randomized trials to support the routine use of Coumadin in Fontan patients.

As with many other forms of ACHD, the occurrence of a clinical arrhythmia should instigate investigation for an underlying hemodynamic abnormality, such as new thrombus formation or other obstruction in the Fontan circuit.

Atrial flutter is extremely common in patients with a previous atriopulmonary Fontan operation. The prevalence increases as the patient ages. Even in patients who seemingly tolerate the arrhythmia well, sinus rhythm should be restored promptly, as hemodynamic compromise may occur unexpectedly and rapidly. Often, TEE will be done to look for thrombus in the right atrium. Direct current (DC) cardioversion of a patient with a Fontan circulation is associated with increased risk, particularly of asystole or bradyarrhythmia immediately after conversion. Sedation and cardioversion should be done with caution and close attention.

Comments: The blood pressure may be difficult to measure in the ipsilateral arm of a patient with a previous BT shunt. In a case with a unilateral BT shunt it is important to be aware of this and measure the blood pressure in the contralateral arm to avoid false readings. In this case both arms had reduced pressure, and blood pressure had to be obtained in the leg.

This patient had a normal oxygen saturation. However, patients with a previous Fontan operation usually have a degree of arterial desaturation for several reasons, including open fenestrations (i.e., surgically created small ASDs), systemic venous collaterals, and pulmonary arteriovenous malformations (the latter mainly if there is or has been a classic Glenn shunt, i.e., an anastomosis between the SVC and the right pulmonary artery excluding the right lung from IVC venous return).

The JVP is typically difficult to see because of poor waveform and significant elevation in patients who have had a Fontan procedure.

The patient has an irregular heart rate, which is atrial fibrillation until proven otherwise. This should always be a cause for concern in a Fontan patient. The patient himself has noted no new palpitations. It is possible that his use of amiodarone has prevented a tachycardic response to new atrial arrhythmia, and thus the patient has not noted a change in heart rhythm. One might suspect the patient to have noted some change in exercise capacity, however.

The second heart sound is usually single in patients with a previous Fontan operation. There are typically no murmurs. Any easily audible or new murmurs should raise concern. For example, they may reflect progressive AV valve regurgitation and impairment of systemic ventricular function.