Comments: Patients with double-inlet ventricle without pulmonary stenosis have an unprotected pulmonary vascular bed and therefore present with signs of heart failure in infancy when the pulmonary vascular resistance has fallen. Pulmonary artery banding is a palliative procedure to limit pulmonary blood flow and prevent pulmonary hypertension. Most patients with double-inlet LV also have ventriculoarterial discordance, meaning the aorta arises from the rudimentary RV. “Holmes heart” is a double inlet left ventricle with normal ventriculoarterial concordance.

The Fontan procedure performed here is a modification of Fontan’s original technique to separate the pulmonary and systemic circulations in the setting of “univentricular” physiology.

Atrial arrhythmias are a common complication following the modified Fontan, increasing with older age at surgery and longer follow-up. They are an important cause of morbidity leading to heart failure, systemic AV valve regurgitation, atrial thrombus formation, and dilation of both the RA and LA. As many as 50% of patients will have had an arrhythmia by the time they reach adulthood.

Sinus node disease is not uncommon following the atriopulmonary Fontan. It may be caused by distortion of atrial structures induced by chronic stretch or by surgical injury to the sinoatrial node artery, which runs across the roof of the RA close to the site of atriopulmonary anastomosis. Sinus node disease has been associated with a higher incidence of atrial arrhythmias than in those with normal RA activation. Atrial pacing is an effective way of maintaining an adequate atrial rate, which in itself may limit the development of further arrhythmias. However, the transvenous approach is often not recommended since it may predispose to venous obstruction and thrombus formation on the leads. A transvenous approach was elected after consideration of risks and benefits. Careful planning was required before embarking on efforts to place a transvenous pacing wire. Securing adequate sensing and pacing thresholds in a highly scarred and hypertrophied chamber can be challenging, and asynchronous pacing due to loss of adequate sensing may be proarrhythmic. Many centers would not attempt this, and instead would use epicardial pacing wires, though this method too has inherent drawbacks, especially long-term lead function. This approach was not felt to be suitable in this particular instance. However, some centers now report success with transvenous pacing.

PLE is a difficult problem in the Fontan population (see Case 62 ). At times the best therapeutic option is cardiac transplantation.

Comments: Young patients are often unaware of the presence of arrhythmia, but absence of symptoms at a heart rate of 190 bpm is unusual. Fontan patients can be particularly vulnerable to low cardiac output during tachyarrhythmias, which should therefore be taken seriously and treated promptly.

Comments: The patient is mildly cyanosed, which is not uncommon in a Fontan patient. This may be due to a residual right-to-left shunt through an atrial communication or extracardiac venovenous collateral vessels and/or secondary-to-intrapulmonary shunting. At the time of Fontan surgery the patch across the left AV valve is commonly placed above the coronary sinus os to avoid the AV conducting system, which leaves coronary venous return draining into the systemic ventricle causing mild arterial desaturation (see Fig. 64-6 ).

The patient has an elevated JVP indicative of elevated RA pressure, a result of the Fontan circulation perhaps aggravated by his recent arrhythmia. Although the jugular vein is still in communication with the RA (unlike an extracardiac or lateral tunnel Fontan, see Case 63 ), no pulsations are seen because the RA is so severely dilated and hypertensive.

Abdominal distension secondary to ascites can be the result of both PLE and systemic venous hypertension.

Comments: The mildly elevated hemoglobin represents secondary erythrocytosis, reflecting the residual right-to-left shunt.

Albumin levels are severely reduced as a consequence of PLE. Lymphangiectasia of the intestinal bed causes loss of albumin, lymphocytes, and immunoglobulin into the gastrointestinal tract, reducing the plasma oncotic pressure and leading to generalized edema, effusions, and sometimes even pulmonary edema. While serum immunoglobulin levels were normal the lymphocyte count was low.

Abnormal hemodynamics and elevated central venous pressure as a result of the “failing” Fontan are felt to play an important role in the development of PLE.