Case #1
A 32-year-old Thai woman (Figure 1, ATS-003) came for a medical advice
on pregnancy planning in 2014. She had a history of abnormal heart
rhythm found at general check-up since childhood. She was asymptomatic
and grew up normally. The patient had one sister (ATS-002) and three
brothers. Her mother (ATS-001) and sister experienced a similar history
of abnormal heart rhythm. Both of them were also asymptomatic and
uneventful. All of her brothers were not affected. There was no history
of sudden unexpected death in the family. She had another post-marital
health check-up and multiform premature ventricular contractions (PVC)
with a short run of non-sustained polymorphic ventricular tachycardia
(PMVT) was uncovered by electrocardiography (ECG). (Figure 2A). Further
cardiac investigation by magnetic resonance imaging together with
transthoracic echocardiography (TTE) showed left ventricular ejection
fraction (LVEF) 25.1%, mild mitral valve regurgitation, mild tricuspid
regurgitation, and no subendocardial scar. Only micrognathia was noted
during physical examination without other dysmorphic features. Clinical
diagnosis of Andersen-Tawil syndrome was suspected.
Genetic testing identified heterozygous likely pathogenic variant inKCNJ2 c.557C>G (p.Pro186Arg) in all affected
members. (Figure 1). Treatment plan had been discussed between
healthcare team and the patient. Catheter ablation was declined
therefore oral Metoprolol was given. The medication dose was gradually
increased to 100 mg daily with no significant change of arrhythmias by
periodic ECG monitoring. The patient decided to discontinue Metoprolol
after she became pregnant.
Her pregnancy was uneventful and cardiac evaluation was done regularly.
The ventricular ectopy became less frequent (Figure 2B). TTE at
gestational age of 24 weeks showed fair left ventricular contraction
with left ventricular ejection fraction (LVEF) at 45-50 %. The patient
was admitted to the hospital due to labor pain at 38 weeks gestation.
Continuous cardiac and fetal monitoring was instituted. Maternal
ventricular ectopy was infrequent. Emergency cesarean delivery was done
under spinal anesthesia due to irregular fetal heartbeats. There was no
intrapartum and immediate postpartum complication. The patient was then
transferred to cardiac care unit (CCU) for postoperative observation.
During CCU stay, she developed persistent PMVT (Figure 2C). Metoprolol
was resumed and 100 mg of Flecainide daily was added to successfully
suppress the arrhythmia. The patient continued to do well until now at 5
months postpartum with occasional ectopic rhythm without ventricular
tachycardia (VT) (Figure 2D).