Tetralogy of Fallot and Biventricular Heart Failure: Submitted by Adam J. Small, MD and Jeremy Moore, MD

Case Synopsis

• AGE: 18 years

• GENDER: Male

• PERSONAL INFORMATION: High school senior

• WORKING DIAGNOSIS: Repaired Tetralogy of Fallot with progressive severe biventricular dysfunction in the setting of sinus node dysfunction and refractory atrial arrhythmias.

History

The patient was born with tetralogy of Fallot and underwent complete repair with transannular patch and ventricular septal defect closure in infancy. By age 16 he had developed progressive right heart dilation and severe tricuspid regurgitation. He underwent pulmonary valve placement, tricuspid valvuloplasty, and right atrial plication.

Six months later, at age 17, he presented with supraventricular tachycardia. He was taken to the electrophysiology laboratory for evaluation. The tachycardia cycle length was 340 ms with 2:1 atrioventricular conduction. The P wave morphology was thought to be consistent with either an atrial tachycardia or atypical atrial flutter. Radiofrequency lesions were delivered to create a line of block from the superior vena cava to the midposterior free wall of the right atrium, as well as from the tricuspid valve to the inferior vena cava. After lesion delivery, the tachycardia could still be induced with isoproterenol administration. The area of earliest atrial activation was then located at the coronary sinus ostium, and ablation was undertaken there. The tachycardia was terminated and was not inducible thereafter.

Four months later, the patient presented to the emergency room with a heart rate of 160 beats/min. Cardioversion was performed with a 50 J synchronized shock, with conversion to sinus rhythm. Unfortunately, the tachyarrhythmia recurred 2 h later. Repeat electrophysiology study and catheter ablation were then performed. An intraatrial reentrant tachycardia circuit was found to involve the isthmus between the right atriotomy and tricuspid valve. It was successfully ablated, along with two other tachycardia foci.

Over the next 2 months, the patient was admitted twice for symptomatic tachyarrhythmia. For both, direct current cardioversion was attempted but was unsuccessful. A 12 lead electrocardiogram from that time revealed atrial flutter with a ventricular rate of 120 beats/min, complete right bundle branch block, and QRS duration of 170 milliseconds. An echocardiogram demonstrated mildly to moderately diminished left ventricular systolic function, which had worsened since the previous month.

Soon after, at age 18, he was taken back to the operating room for a redo sternotomy, tricuspid valve replacement with 29 mm Mosaic porcine valve, modified Maze procedure, and biventricular implantable cardioverter-defibrillator (ICD) (St Jude Unify Assura CRT-D; St Jude Medical, St Paul, MN, USA). Eight cryolesions were delivered within the right atrium during the Maze procedure. A right atrial pacemaker lead implant was then attempted in numerous endocardial and epicardial locations. Reliable atrial sensing and pacing could not be achieved, a difficulty attributed to the MAZE procedure, but a bipolar lead was placed transmurally into the atrial myocardium (St Jude Tendril STS, 46 cm; St Jude Medical, St Paul, MN, USA). Likewise, an epicardial bipolar lead (Enpath Myopore Sutureless Myocardial Pacing Lead, 35 cm; Enpath Medical, Minneapolis, MN, USA) was placed with one electrode on the right ventricular free wall and the other electrode on the left ventricle for biventricular pacing. A subcutaneous defibrillation coil (Medtronic Subcutaneous Lead System, 41 cm; Medtronic, Minneapolis, MN) was then implanted along the posterior pericardium. After the operation, the patient was in junctional rhythm. Transesophageal echocardiogram demonstrated severely diminished biventricular function and moderate-to-severe tricuspid insufficiency.

The atrial tachyarrhythmia quickly recurred and his condition worsened over the next month. He re-presented to the hospital with lightheadedness, nausea, and chest pain. Cardioversion was unsuccessful with 100, 150, and 200 J synchronized energy. He was started on amiodarone and milrinone infusions. His tachyarrhythmia improved with amiodarone, but the left ventricular ejection fraction had deteriorated to 20%.

He was transferred to our facility for consideration of orthotopic heart transplantation. Device interrogation revealed a nonfunctioning atrial lead but otherwise normal device function and lead characteristics. The pacing mode was set to VVI with a lower rate of 70 beats/min. The underlying rhythm was junctional and poorly tolerated.

Current Symptoms

The patient experienced palpitations during episodes of supraventricular tachycardia, which were recurrent upon transfer. He also had chest pain at the site of his sternotomy incision. He had no dyspnea, diaphoresis, cough, fevers, chills, nausea, vomiting, or diarrhea.

Current Medications

• Milrinone infusion 0.5 mcg/kg/min

• Amiodarone 200 mg oral daily

• Enalapril 2.5 mg oral twice daily

• Furosemide 20 mg intravenous every 12 h

• Enoxaparin 60 mg subcutaneous every 12 h

Physical Examination

• 104 BP/65 mmHg, HR 81 bpm, oxygen saturation 97% on 2 L via nasal cannula.

• Weight 65.5 kg

• Appearance: The patient appeared comfortable with normal work of breathing.

• Neck veins: Jugular veins were distended.

• Lungs/chest: Crackles were appreciated at the left base. Otherwise aeration was normal.

• Heart: The rhythm was irregular. S1 and S2 were appreciated. A grade II/VI systolic ejection murmur was appreciated at the left upper sternal border.

• Abdomen: The abdomen was normal with no ascites or organomegaly.

• Extremities: The extremities were warm without edema.

• Skin: Midline sternotomy and left upper chest incisions were clean, dry, and intact.