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).