Initial Clinical Experience with Cardiac Resynchronization Therapy Utilizing a Magnetic Navigation System

Progress in zero-fluoroscopy implantation of cardiac electronic device

Fluoroscopy is the imaging modality routinely used for cardiac device implantation. Due to the rising concern regarding the harmful effects of radiation exposure to both the patients and operation staffs, many efforts have been made to develop alternative techniques to achieve zero-fluoroscopy implantation. In this review, we describe the different methods aimed at avoiding the application of fluoroscopy in recent years, and evaluate their feasibility and safety in cardiac electronic device implantation.

Zero x-ray cardiac resynchronization therapy device implantation guided by a nonfluoroscopic mapping system: A pilot study

BACKGROUND

Fluoroscopic guidance is the standard tool used in device implantation. This means that both the patient and the operator are exposed to radiation, which may sometimes be high. The possibility of single-lead permanent pacemaker implantation without fluoroscopy has already been demonstrated.

OBJECTIVE

The aim of our study was to investigate the feasibility and reliability of biventricular device implantation guided only by an electroanatomic navigation system.

METHODS

Sixty-one patients with heart failure underwent implantation of a cardiac resynchronization therapy (CRT) device with or without defibrillator (CRT-D; CRT-P). The procedure was performed with or without fluoroscopy guidance (Rx+; Rx0). In the latter case, the EnSite Velocity system was used; this system is able to reconstruct the anatomy and activation of the cardiac chambers by simultaneously collecting a "cloud" of anatomical points from multiple electrodes.

RESULTS

Lead positioning was achieved in 24 of 26 patients undergoing CRT implantation without fluoroscopy (92% success). No complications were observed during the procedure and no catheter dislodgment occurred the day after the implantation or during 1-month follow-up. Procedure time progressively decreased from 136 minutes in the first case to 59 minutes in the last one, suggesting that operators gradually gained confidence while using the new technique.

CONCLUSION

Our study demonstrates the feasibility, efficacy, and safety of lead positioning guided only by the nonfluoroscopic EnSite Velocity mapping system without the use of fluoroscopy in CRT-P or CRT-D implantation. The benefits in terms of significantly reduced fluoroscopy exposure are associated with technical and clinical advantages.

Cardiac Resynchronization Therapy Device Implantation Using a New Sensor-Based Navigation System

Background—

Cardiac resynchronization therapy (CRT) device implantation can be challenging, time consuming, and fluoroscopy intense. To facilitate left ventricular lead placement, a novel sensor-based electromagnetic tracking system (MediGuide Technology [MGT], St. Jude Medical) has been developed. We report the results of the First Human Use study evaluating the feasibility, safety, and performance of a novel CRT implantation approach using electromagnetic trackable operation equipment.

Methods and Results—

Fifteen consecutive patients (66±8 years, 53% male) with an established indication for CRT were implanted using the new tracking technology. Demographics, anatomical information, detailed fluoroscopy need, procedure time, and adverse events were collected. Patients were followed up for 4 weeks after implantation. The CRT system was successfully implanted with a lateral or posterolateral left ventricular lead position in all patients. The total procedure time was 116±43 minutes, the median total fluoroscopy time (skin to skin) was 5.2 (Q1–Q3, 3.0–8.4) minutes, and the median fluoroscopy time for left ventricular lead deployment (coronary sinus [CS] cannulation to withdrawal of CS sheath) measured 2.6 (Q1–Q3, 1.6–5.6) minutes. There were no severe complications that required an acute intervention or reoperation during the perioperative and postoperative periods.

Conclusions—

Use of the MGT tracking technology allows for safe and successful CRT implantation with the potential for reduced fluoroscopy time. Future randomized studies are needed to validate these data.

Clinical Trial Registration—

URL http://www.clinicaltrials.gov . Unique identifier: NCT01519739.

Stereotaxis Niobe magnetic navigation system for endocardial catheter ablation and gastrointestinal capsule endoscopy

The use of robotic instruments capable of assisting medical staff during interventional or diagnostic procedures is growing rapidly today. Recently, a robotic system (Niobe, Stereotaxis Inc., USA) has been developed for navigating magnetically enabled tools inside the human body by controlling a magnetic field. This paper reports the fundamentals of this technology and reviews its application in two specific medical fields, cardiology and gastroenterology, in which its uses are different and are at dissimilar stages of development. In the first case, the system is already approved and employed for clinical treatments, such as magnetic steering of endocardial catheters for atrial fibrillation ablation, which is specifically considered in this article. In the second case, initial investigations are being performed today to study the potential magnetic maneuverability of ingestible video capsules adopted for endoscopic explorations of the digestive tract. This paper reviews current achievements and highlights future challenges related to each of these applications.

Magnetically guided left ventricular lead implantation based on a virtual three-dimensional reconstructed image of the coronary sinus

Aims

Left ventricular (LV) lead implantation is feasible using remote magnetic navigation of a guidewire (Stereotaxis, St Louis, MO, USA). A novel software that performs a three-dimensional (3D) reconstruction of vessels based on two or more angiographic views has been developed recently (CardiOp-B system™, Paeion Inc., Haifa, Israel). The objective of this paper is to evaluate: (i) the performance of the 3D reconstruction software which reproduce the anatomy of the coronary sinus (CS) and (ii) the efficacy of remotely navigating a magnetic guidewire within the CS based on this reconstruction.

Methods and results

In patients undergoing cardiac resynchronization therapy implantation, a 3D reconstruction of the CS was performed using the CardiOp-B™ system. Accuracy of the reconstruction was evaluated by comparing with the CS angiogram. This reconstruction was imported into the Stereotaxis system. On the basis of the reconstruction, magnetic vectors were automatically selected to navigate within the CS and manually adjusted if required. Feasibility of deploying the guidewire and LV lead into the selected side branch (SB), fluoroscopy time (FT) required for cannulation of the target SB, and total FT were also evaluated. Sixteen patients were included. In one case, the software could not reconstruct the CS. The quality of the reconstruction was graded as good in 13 and poor in 2. In 10 cases, manual adjustments to the traced edges of the CS were required to perform the 3D reconstruction, and in 5, no adjustments were required. In 13 patients, the target SB was engaged on the basis of the automatically selected vectors. In two cases, manual modification of the vector was required. Mean total FT was 23 ± 14 min and the FT required to cannulate the target SB was 1.7 ± 1.3 min.

Conclusion

A 3D reconstruction of the CS can be accurately performed using two angiographic views. This reconstruction allows precise magnetic navigation of a guidewire within the CS.

Use of the Stereotaxis Niobe magnetic navigation system for percutaneous coronary intervention: results from 350 consecutive patients

INTRODUCTION

The Stereotaxis Niobe magnetic navigation system (MNS; Stereotaxis, St. Louis, MO) facilitates precise vector based navigation of magnetically-enabled guidewires for percutaneous coronary intervention (PCI) by using two permanent magnets located on opposite sides of the patient table to produce a controllable magnetic field. The objective of this study is to describe the results of a large patient series using this system, to compare the results with a historical control group, and to detail the MNS learning curve.

METHODS

We prospectively collected data on 439 lesions in 350 consecutive PCI patients using the MNS predominantly using the radial approach. All data were entered into a customized database to capture the key parameters and then compared with a previously collected stent registry from the same center.

RESULTS

In 410/439 lesions (93%) the wire crossed the lesion successfully using the MNS. Twenty-five of the 35 failures were chronic total occlusions. No wire perforations or dissections occurred in this population. Lesion crossing time was 81 +/- 168 sec (mean +/- SD), and fluoroscopy time was 64 +/- 123 sec. A clear learning curve was evident after the first 80 patients. Contrast use was reduced when compared with a historical control group. Procedural and fluoroscopy times were similar.

CONCLUSIONS

Use of the MNS may enable the successful performance of more complex procedures in the cardiac catheterization laboratory with an improvement in time efficiency.

Magnetic Navigation in Left-Sided AV Reentrant Tachycardias: Preliminary Results of a Retrograde Approach

INTRODUCTION

A novel magnetic navigation system allows remote guidance of floppy radiofrequency (RF) ablation catheters. We evaluated the feasibility of mapping and ablation of left-sided accessory pathways (APs) using the retrograde transaortic approach with this system. This might open the gate to retrograde ablation of left atrial arrhythmias.

METHODS AND RESULTS

Twenty consecutive patients were included. A Helios II was used in five and in 15 a Celsius RMT RF catheter with higher magnetic mass and different flexibility was used. Mapping and ablation were attempted. The learning curve was analyzed. Ablation was acutely successful in 60% of the patients using the Helios II and in 80% using the Celsius RMT. Median procedure time was 158 minutes, with median patient and physician fluoroscopy times of 26 and 4 minutes. In the last 10 patients, procedure times became significantly shorter (median 122 minutes, only Celsius RMT catheters) and standard catheters had to be used only twice. No complications occurred.

CONCLUSIONS

Remote retrograde transaortic RF ablation of left-sided APs is feasible, safe, and reduces the physician's fluoroscopy exposure. There is a very steep initial learning curve, with the success rate increasing from 50% in the first 10 cases to 80% in the last 10 cases. Different catheter configurations may influence the outcome.