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.
The left atrial appendage (LAA) is an uncommon site for origin of ectopic atrial tachycardia [
A previously healthy 7-year-old girl had a three-day history of cough and flu-like symptoms. Her grandfather noted she had a fast heart rate. She was taken to a local hospital reporting increasing fatigue and dyspnea with exertion for the prior three weeks. The patient was hemodynamically stable at the time of presentation. Her heart rate was 230 beats per minute. Adenosine was given multiple times which resulted in transient AV dissociation, but had no effect on the tachyarrhythmia. She received a bolus of procainamide, and was transferred to our children’s hospital for further evaluation and treatment.
Upon arrival, her heart rate was 175 beats per minute. The remainder of her vital signs were normal, as was her physical examination. The initial ECG demonstrated a narrow complex tachycardia (Figure
ECG showing narrow complex tachycardia with a long RP pattern.
She was taken to the catheterization lab for an electrophysiology study. She was intubated and placed under general anesthesia by a pediatric anesthesiologist. Three femoral venous sheaths were inserted into the right femoral vein via the modified Seldinger technique. A decapolar coronary sinus catheter (Biosense Webster, Diamond Bar, CA, USA) was placed. A D-curve 4.0 mm Navistar ablation and mapping catheter (Biosense Webster, Diamond Bar, CA, USA) was inserted to the His position. A quadripolar catheter (St. Jude Medical, St. Paul, MN, USA) was placed in the right ventricular apex. The tachycardia cycle length = 330 msec with 1 : 1 conduction. The PR interval length = 130 msec, QRS duration = 77 msec, AH interval = 70 msec, and the HV interval = 40 msec. A three-dimensional electro-anatomic activation map (CARTO 3, Biosense Webster, Diamond Bar, CA, USA) of the right atrium displayed a broad septal region of early activation. The activation in the coronary sinus was distal to proximal, consistent with a left atrial focus.
While performing the mapping procedure, before transseptal access or ablation was attempted, the blood pressure dropped precipitously. On fluoroscopy, the cardiac silhouette demonstrated no cardiac motion, consistent with pulseless electrical activity (PEA). Cardiopulmonary resuscitation (CPR) was initiated and intravenous epinephrine was given with return of circulation. An emergent transthoracic echocardiogram revealed no pericardial effusion. Over the next 120 minutes, the patient suffered three further PEA arrests, each time with return of spontaneous circulation after CPR and epinephrine. Due to hemodynamic instability and poor left ventricle contractility, we initiated emergent veno-arterial extracorporeal membrane oxygenation (ECMO) utilizing the right femoral vein and right carotid artery. Using ECMO support, her condition stabilized promptly. However, she remained in atrial tachycardia with 1 : 1 conduction in spite of repeated cardioversions and intravenous amiodarone. An echocardiogram showed severely depressed left ventricular function (SF = 6%) and mild left atrial enlargement. The next day, the echocardiogram revealed increasing left atrial size and pressure. An atrial septostomy was indicated to relieve left atrial hypertension. Given the incessant nature of her tachycardia and failure to resolve on antiarrhythmic medication, a left atrial ablation would be performed following the atrial septostomy procedure.
The patient was bought to the catheterization lab on ECMO support. A transseptal puncture was performed using standard technique, followed by a blade atrial septostomy using a 13.4 mm blade catheter (Cook Inc, Bloomingtion, IN, USA). With access to the left atrium obtained, a detailed electro-anatomic map of the left atrium was created with the CARTO mapping system. The tachycardia cycle length was now 290 msec. The electro-anatomic map clearly demonstrated focal activation originating in the very distal left atrial appendage. A contrast injection into the left atrium demonstrated a long and trabeculated left atrial appendage (Figure
LAO 90 degree contrast injection of LAA ((a) marked by white arrow) and successful ablation site (black arrow in (b)).
3D activation map of left atrium in AP projection.
Post-ECMO decannulation, a repeat echocardiogram demonstrated progressive improvement of the left ventricular systolic function. As the sedation was weaned, she showed remarkable improvement in her neurological status including purposeful movements. Three days after the procedure, she was extubated uneventfully and displayed no neurological deficits. With continued excellent progress, she was discharged to home 10 days after the procedure. Follow-up clinic evaluations demonstrated normalization in the left ventricle systolic function (SF = 32%) and return to her baseline activity level. For 12 months after the procedure, she has not had any atrial tachycardia noted by report, exam, or repeated 14 day continuous ambulatory monitoring exam. She has made a full recovery and is now on a local soccer team.
Focal atrial tachycardia can arise from various portions of the atrium [
Mohsin Khan declares that he has no conflict of interests. Darryl Elmouchi is a consultant (modest) at the St. Jude Medical, Biosense Webster; Biotronik, Speaker’s Bureau; Boehringer Ingelheim, Speaker’s Bureau; Medtronic; Spectranetics, Pfizer Speaker’s Bureau; and Bristol Meyers Squibb, Speaker’s Bureau. Andre Gauri is a consultant (modest) at Medtronic at St. Jude Medical, Biosense Webster, and Boehringer Ingelheim, Speaker’s Bureau. Ronald Grifka is a consultant (modest) at St. Jude Medical and W. L. Gore Inc.