Repeated Aborted Sudden Cardiac Death with Long QT Syndrome in a Patient with Anomalous Origin of the Right Coronary Artery from the Left Coronary Cusp
A 15-year-old female with a prior history of aborted cardiac death and surgical correction of anomalous origin of the RCA was referred to the cardiology department due to repeated aborted sudden cardiac death after physical exertion with boxing. The initial electrocardiogram (ECG) showed polymorphic ventricular tachycardia (). Biphasic 200 joules defibrillation restored the heart to sinus rhythm and cardiopulmonary function recovered without neurologic sequelae. Two years prior to this event, she experienced chest discomfort followed by aborted sudden cardiac death after heavy exercise for the first time. Initial ECG at the emergency room showed pulseless electrical activity. She was successfully resuscitated after basic life support maneuvers and fully recovered with hypothermic treatment after being admitted to the emergency department. Her family history of structural heart disease, syncope or sudden cardiac death was unremarkable. Several cardiac examinations were performed at that time. Echocardiography demonstrated no structural heart disease with a normal left ventricular ejection fraction. Cardiac computed tomography revealed anomalous origin of the RCA from the left coronary cusp coursing between the pulmonary artery and the aorta (). Her follow-up ECGs after stabilization showed a sinus rhythm with an inverted T wave and a prolonged QT interval which was suggestive of congenital LQTS (). She was not taking any medications which can prolong the QT interval and laboratory findings did not show electrolyte abnormalities. But this finding was overlooked and anomalous origin of the RCA was provisionally considered as the cause of the aborted cardiac arrest. She underwent surgery to re-implant the anomalous RCA from the left to the right sinus of Valsalva. After receiving surgical correction of anomalous origin of the RCA, she had been doing well before the second event of aborted cardiac death developed. Coronary angiogram with a provocation test using ergonovine was done after the second event, and it revealed no significant abnormalities and the re-implantation site of the RCA ostium was intact. An electrophysiologic study was performed to rule out possible causes of other arrhythmias leading to cardiac arrest. However no other arrhythmia was induced and also polylmorphic ventricular tachycardia was not inducible with programmed stimulation. The ECG after restoring the heart to sinus rhythm showed still significant prolongation of the QT interval, resulting in the diagnosis of LQTS, probably type I, regarding her clinical presentation, even though the ECG pattern showed a prolonged QT interval and a notched T wave suggesting LQTS type 2. Gene studies were recommended, but declined by her family. ECGs of her parents showed no significant QT prolongation. Medication with a β-blocker (atenolol) was started and the dose was titrated up to 1.3 mg/kg (50 mg bid, regarding her body weight; 78 kg). A follow-up exercise tolerance test revealed blunting of the heart rate response during maximal exertion and she was instructed to avoid heavy exercise. She remained free from ventricular arrhythmias while she was on a β-blocker medication during the follow-up of more than 6 months. Her serial follow-up ECGs showed significant QTc prolongation of >500 ms consistently.