Utility of the Manual Override Feature in Catheter Robotics’ Amigo Robotic Catheter Manipulation System

Introduction

In a previous case report published in EP Lab Digest, we described our first experiences with the Amigo Remote Catheter System (Catheter Robotics, Inc.), with the ThermoCool SmartTouch catheter and Carto 3 System (Biosense Webster, Inc., a Johnson & Johnson company) for mapping, as positive with no unforeseen complications.¹ The Amigo system has a feature to allow the ablation catheter to be removed if the operator prefers to manually manipulate the catheter.² This case report describes the use of this manual override feature.

Case Report

A 66-year-old woman with a history of incessant nonsustained ventricular tachycardia (NSVT) and mild dilated cardiomyopathy presented for an electrophysiology (EP) study with catheter mapping. Figure 1 shows a 12-lead electrocardiogram (ECG) with NSVT showing a left bundle branch block morphology and inferior axis. The transition zone was between V2 and V3. The patient underwent an EP study with mapping that identified a high right ventricular outflow tract (RVOT) located just beneath the pulmonary valve toward the septum. There was some difficulty in manipulating the catheter in the RVOT in this patient, due to their anatomy, using the Amigo system. The operator felt more comfortable proceeding with this case manually due to the user’s experience and familiarization in manual manipulation, because it was a challenge to get the catheter into the RVOT, and some very high and potentially dangerous readings (as indicated by contact force sensing values greater than 70 grams) were indicated. Fortunately, the Amigo system provides the option to remove the catheter from the system without breaking sterility if the operator prefers to manually manipulate the catheter (Table 1). Using sterile gloves, the catheter is released from the Amigo docking station along with the disposable nosecone. The catheter body is then removed from the Amigo track. Once completely released from the robotic system, the catheter is free to be manually manipulated. In this case, this feature provided a comfort level that was very helpful in finding the optimal ablation site and achieving a good result. Manual radiofrequency catheter ablation was then performed with the ThermoCool SmartTouch catheter with 30 Watts at 60 seconds for each attempt. Figure 2 shows radiofrequency ablation obtained using the Carto 3 System with contact force sensing. Contact force sensing was helpful during this procedure; it identified when untoward force was being applied at the catheter tip, and allowed the operator to back off on the forward pressure. Although the patient received deep sedation by an anesthesiologist using propofol, she was awake during parts of the procedure (particularly around the time of the ablation component of the procedure), and felt some chest pain even with low contact force applied during mapping. The operator (TC) felt comfortable applying radiofrequency ablation manually because of the low contact force pressure recorded at the time (less than 20 grams). No complications and/or perforation occurred both during or following the procedure.

Discussion

Remote manipulation with the Amigo system, the ThermoCool SmartTouch catheter, and Carto 3 System can be helpful in safely manipulating electrophysiology catheters. Amigo mimics manual manipulation movements, and just like with manual manipulation, Amigo can be difficult in some myocardial areas because of unusual anatomy. High contact force sensing measurements in real time can alert the operator to back off on forward force in both manual and remote manipulation. When ablating unusual anatomy, it may be helpful to use manual manipulation, which is more familiar to the operator. Figure 3 shows the operator using the manual manipulation maneuver to map and perform the ablation. 

Amigo, together with the ThermoCool SmartTouch catheter, allows the operator to monitor contact force and maintain catheter stability while remotely manipulating the catheter. The advantage with the Amigo system is that it uses standard catheters and provides the option for the operator to easily switch between manual and robotic manipulation.² An operator using another remote catheter system would likely have to remove the catheter from an encased steerable sheath and restart the procedure or switch catheters from a magnetic catheter to a standard ablation catheter.³ This additional maneuver with those systems would add time and cost, and may affect patient safety.

In summary, the manual override feature of the Amigo Remote Catheter System with the ThermoCool SmartTouch catheter can be beneficial in manually performing catheter manipulation when the patient has unusual anatomy. This allows operators to achieve better results and optimize patient safety. 

Disclosures: Mr. Kersten, Dr. Asheld, and Mr. Mitrache have no conflicts of interest to report regarding the content herein. Dr. Cohen is the inventor of the robotic system known as the Amigo; he no longer has any financial interest in this product. 

References 

1. Chung JA, Kersten DJ, Mitrache A, Cohen TJ. Contact force mapping with remote manipulation of a mapping catheter. EP Lab Digest. 2014;14(9):17-18. 
2. Knight B, Ayers GM, Cohen TJ. Robotic positioning of standard electrophysiology catheters: a novel approach to catheter robotics. J Invasive Cardiol. 2008;20(5):250-253.
3. Datino T, Arenal A, Pelliza M, et al. Comparison of the safety and feasibility of arrhythmia ablation using the Amigo Robotic Remote Catheter System versus manual ablation. Am J Cardiol. 2014;113(5):827-831.