Treating Tet Spells With Disopyramide in a 72-Year-Old Awaiting Primary Repair of Tetralogy of Fallot

An adult with unrepaired tetralogy of Fallot presented with frequent tet spells. Her course was complicated by severe cyanotic spells and tachycardia-bradycardia syndrome that limited beta blocker use to stabilize her spells. She markedly improved after disopyramide initiation and underwent successful tetralogy of Fallot repair with excellent functional outcome.

sodes occurred with increasing frequency leading up to presentation.
During her initial admission, she was treated for possible abdominal sepsis with fluid boluses and antibiotics.Laboratory test results were notable for white blood cell count of 21,000/mL, bicarbonate level of 15 mmol/L, and lactic acid level of 8.3 mmol/L.Although she initially improved, she experienced recurrent spells of severe hypoxemia and visible cyanosis, prompting her transfer to our center for cardiac surgical evaluation.On arrival, vital signs were notable for oxygen saturation of 88% on room air.Physical examination revealed a 2/6 systolic ejection murmur, a left lateral thoracotomy scar, equal pulses in the extremities, and an absence of clubbing of her fingernails.Previously noted abnormalities in blood work had resolved.Shortly after admission, she experienced a spell with severe cyanosis with oxygen saturation as low as 29%, during which the patient tensed her body and brought her knees to her chest.She remained conscious and interactive throughout, with normal recall of events

LEARNING OBJECTIVES
To describe one of the oldest reported patients with unrepaired TOF.To describe treatment strategies in TOF.To recognize the role of disopyramide to relieve hypercyanotic spells when patients cannot tolerate typical treatment regimens.

PAST MEDICAL HISTORY
The patient's medical history included TOF with unsuccessful attempt at surgical palliation in India during childhood, hypothyroidism, and reported seizure disorder.

DIFFERENTIAL DIAGNOSIS
The differential diagnosis included seizure, sepsis, and worsening of the severity and frequency of cyanotic episodes in a patient with unrepaired TOF.

MANAGEMENT
Her course was notable for recurrent stereotyped episodes, which were determined to be tet spells.
Ongoing use of phenylephrine to maintain mean Clinically significant arrhythmias are another major source of morbidity in TOF, both repaired and unrepaired. 5,6Our patient suffered from tachycardiabradycardia syndrome, which complicated management by preventing the use of metoprolol.We therefore tried to manage rhythm and dynamic outflow obstruction with the Class Ia antiarrhythmic disopyramide.Like its benefit in hypertrophic obstructive cardiomyopathy because of its negative inotropic action, disopyramide can alleviate dynamic RVOT obstruction in TOF patients. 7QT prolongation and arrhythmias are reported complications that should be monitored for 8 ; however, our patient tolerated disopyramide, well with suppression of hypercyanotic spells and arrhythmias until surgical repair.

FUNDING SUPPORT AND AUTHOR DISCLOSURES
The authors have reported that they have no relationships relevant to the contents of this paper to disclose.

Electrocardiogram (Figure 1 )
demonstrated normal sinus rhythm with right ventricular (RV) hypertrophy and ST-/T-wave changes in the anterolateral leads.X-ray (Figure 2) and nongated computed tomography imaging of the chest demonstrated no pulmonary pathology.Transthoracic echocardiograms were obtained on admission and hospital day 5 and demonstrated normal left ventricle size and systolic function as well as findings consistent with unrepaired TOF: a large subaortic perimembranous ventricular septal defect (VSD) with low-velocity, bidirectional flow; overriding aorta with moderate root dilation with no obvious regurgitation; and a mildly dilated and severely hypertrophied RV with severe, dynamic outflow tract stenosis with a peak gradient of 70 to 90 mm Hg.Cardiac computed tomography scan demonstrated unrepaired TOF consisting of large anterior conal malalignment VSD with overriding aorta, RV hypertrophy and multilevel severe RVOT obstruction, predominantly subvalvular but with dysplastic bicuspid pulmonary valve and moderate supravalvular narrowing.No significant obstruction or hypoplasia was present in the distal pulmonary vasculature.No patent aortopulmonary shunt was identified.

FIGURE 2
FIGURE 2 Chest X-Ray Film