Mechanical circulatory support to control medically intractable arrhythmias in pediatric patients after cardiac surgery

A case of life-threatening supraventricular tachycardia storm associated with theophylline toxicity

A 76-year-old man taking theophylline was admitted to our hospital with congestive heart failure and supraventricular tachycardia (SVT). After admission, he developed cardiogenic shock as a result of SVT storm, which was refractory to medical treatment including adenosine and electrical cardioversion. The serum theophylline concentration at admission was identified as toxic. Therefore, theophylline toxicity was considered as a major cause of the SVT storm. Hemodynamic stability was achieved by using mechanical circulatory support. Additionally, continuous hemodiafiltration was performed to remove theophylline, and it was effective for suppression of SVT. The patient was successfully weaned off mechanical circulatory support. After the patient's general status had improved, an electrophysiological study was performed, and it showed orthodromic atrioventricular reentrant tachycardia with a right free wall accessory pathway. Radiofrequency catheter ablation was successfully performed. <Learning objective: SVT is often hemodynamically stable and medically well-controllable with adenosine. However, SVT is occasionally refractory or life-threatening under specific conditions such as theophylline toxicity, since theophylline has an inhibitor effect on adenosine. Mechanical circulatory support should be used in case of life-threatening SVT storm associated with theophylline toxicity.>.

Radiofrequency Ablation of a Left Atrial Appendage Tachycardia on ECMO Support

Extracorporeal membrane oxygenation (ECMO) has been utilized in the pediatric population for cardiogenic shock secondary to medically intractable arrhythmias. There is limited experience with cardiac radiofrequency ablation (RFA) on these patients while on ECMO. A 7-year-old girl presented with a tachycardia-mediated cardiomyopathy secondary to a left atrial appendage tachycardia. She suffered a cardiac arrest due to pulseless electrical activity and was placed on ECMO. Due to elevated left atrial pressures and the refractoriness of her arrhythmia to cardioversion and antiarrhythmic therapy, while on ECMO, blade atrial septostomy and radiofrequency ablation were performed. The patient tolerated the procedure well and was successfully decannulated. Her cardiac function normalized within four weeks of the ablation procedure. Twelve months after the procedure, she remains completely well, with no symptoms or tachycardia.