Fluoroscopy is commonly used in many cardiovascular procedures such as pacemaker and defibrillator implantation. During implantation, the leads for intracardiac defibrillator devices are guided through the introducer under fluoroscopic observation to aid in the location and adequate fixation of the leads within the chambers of the heart.1 Furthermore, with implantation of biventricular devices for resynchronization therapy, fluoro times become more prolonged as it takes more time to locate the os of the coronary sinus to allow access for the LV lead.2 Fluoroscopy also only provides a 2D view of catheter movement and position within the heart, making it difficult at times to adequately position catheters.
Up until now, the feasibility of electroanatomical mapping for adequate placement of ICD leads had been relatively unknown. Recently, systems for non-fluoroscopic 3D catheter navigation through the cardiac chambers and vascular structures have been developed. The technology has progressed enough that in the most recent literature the possibility of implanting pacemakers using these tools and without the use of fluoroscopy is a more prominent possibility.3 A prospect that Del Greco and colleagues were able to demonstrate with the use of electroanatomical mapping in the implantation of a CRT-ICD device.4
Another area driving the push for implementation of electroanatomical 3D mapping involves the subset of patients in which fluoroscopy is too high risk or even contraindicated. One such subset is the pregnant population. This population represents a problem in which exposure to fluoroscopy is contraindicated and endangers the mother and child. Tuzcu et al were able to demonstrate the feasibility of electroanatomical mapping in the implantation of an ICD in a pregnant patient.5 In the case study, they were able to demonstrate that electroanatomical mapping was not only feasible but also a safe alternative to the use of fluoroscopy in patients where it may be contraindicated. This finding can also be applied to the general population undergoing implantation of a dual-chamber ICD.2 Another subset population may be those individuals who have chronic kidney disease or near end-stage kidney disease in which exposure to contrast may induce nephropathy. This may prove to be a safer alternative and allow for the prevention of unnecessary contrast exposure.
In this paper, we demonstrate the use of electroanatomical mapping for the implantation of a dual-chamber ICD as well as its use in the implantation of a BiV intracardiac defibrillator.
Case 1: Implantation of Dual-Chamber Intracardiac Defibrillator
The patient was an 81-year-old female with past medical history of coronary artery disease, inferior wall aneurysm, inferior wall scar, and recurrent sustained ventricular tachycardia. She had two episodes of ventricular tachycardia; each was sustained with a cycle length of 380 ms. The morphology of her ventricular tachycardia was originating from her inferior wall scar. During these episodes, the patient was symptomatic with associated palpitations and shortness of breath. Therefore, dual-chamber intracardiac defibrillator implantation was pursued for secondary prevention.
After informed consent, the patient was brought to the EP lab. She was then prepped and draped in the usual sterile fashion. Using ultrasound guidance (SonoSite, Inc., Bothell, WA), the left axillary vein was visualized, and using a micropuncture needle, the left axillary vein was punctured and later exchanged for a standard J wire. This was done twice. The patient was under general anesthesia, given that she had a prior history of ventricular tachycardia, to maintain airway throughout the procedure in case of hemodynamic compromise. Blood pressure and vitals remained stable throughout the procedure.
An oblique incision was done on the skin. The pocket was subsequently made in the left pectoral area. A 7 French sheath was inserted through the first wire into the axillary vein. The right ventricular lead was attached to the EnSite mapping system (St. Jude Medical, St. Paul, MN), and electroanatomical mapping was done of the superior vena cava (SVC), right atrium, inferior vena cava (IVC), and right ventricle. Position of the catheter was confirmed by the presence of atrial and ventricular electrograms (EGM). After the anatomy was obtained, the right ventricular lead was advanced into the right ventricular apex. This was confirmed under electroanatomical mapping as seen in Figure 1. The lead helix was deployed into the apical myocardium. Pacing, sensing and impedance were satisfactory at that position.
The right atrial lead was subsequently advanced through another 6 French sheath into the SVC and into the right atrium via the electroanatomical mapping that was previously obtained (Figure 1), and was advanced into the right atrial appendage. Before attaching the lead, it was confirmed to have large enough P waves through the analyzer. The lead was then actively fixated into the appendage and sutured into the pectoral muscle. The pocket was then irrigated with vancomycin and antibiotic. Snapshot fluoroscopy of less than 0.1 minute was done to confirm right ventricular and right atrial lead positions as well as appropriate full deployment of the helix.
The leads were attached to the device, and the device was inserted into the pocket and sutured in place with adequate hemostasis.
Case 2: Insertion of BiV Intracardiac Defibrillator
The patient was a 36-year-old male with nonischemic cardiomyopathy. Prior angiogram showed non-occlusive coronary artery disease (CAD). The patient had been optimized on medical therapy for 9 months with no significant change to his ejection fraction, which continued to be 20% despite optimal medical therapy. The patient was considered to be in class III heart failure, and was scheduled for BiV intracardiac defibrillator placement.
After informed consent, the patient was brought to the EP lab. The patient was then prepped and draped in the usual sterile fashion. The patient was given moderate sedation by the anesthesia department. Next, the right internal jugular vein was accessed using SonoSite guidance and micropuncture needle. A 7 French lock-in sheath was inserted. A CSL decapolar catheter (St. Jude Medical) was advanced through the right internal jugular vein and into the right atrium, followed by the right ventricle. Electroanatomical mapping was then obtained of the right atrium and right ventricle. Care was taken to identify the junctions of the IVC and SVC to the right atrium. Using EGM guidance with electroanatomical mapping, the CSL catheter was then advanced into the coronary sinus (Figure 2). Subsequently, the right ventricular lead was advanced using the aid of electroanatomical guidance to the right ventricle. During advancement, further anatomic collection was obtained and subsequently advanced to a basal RV position. Later this was repositioned in a more apical position. The right atrial lead was then advanced once again using the aid of electroanatomical mapping, and eventually placed into the right atrium and later positioned into the right atrial appendage after left ventricular lead positioning.
Next, a 4 French deflectable decapolar catheter was advanced through a 9 French sheath and through the outer CPS Direct SL catheter (St. Jude Medical) with a curve of 115 cm. The EP catheter was then advanced without difficulty under electroanatomical mapping and EGM guidance into the coronary sinus with the guidance of prior CSL catheter, which was engaged from the right internal jugular vein. The outer sheath was then tracked over the EP catheter under electroanatomical mapping.
Further anatomical mapping was done with the EP catheter, and using the prior angiogram films showing the tributaries of the coronary sinus, we were able to re-identify the tributaries of the coronary veins. We were then able to engage the left ventricular lead into the left lateral and posterior vein with over-the-wire technique, and subsequent pacing, sensing, and thresholds were adequate with no evidence of diaphragmatic pacing at 10v.
The pocket was then irrigated with vancomycin and antibiotic. Snapshot fluoroscopy of 0.3 minute was done to confirm RV, LV, and right atrial lead positions. The leads were attached to the device, and the device was inserted into the pocket and sutured in place with adequate hemostasis.
Both patients had follow up with no immediate or late complications. There was remarkable improvement of functional status and ejection fraction as well as narrowing of the QRS on the EKG for the BiV patient (Figures 3 and 4).
In these two cases, we were able to demonstrate that using electroanatomical 3D mapping was helpful in reducing the amount of fluoroscopy to near zero minutes. We were also able to eliminate use of contrast with detailed anatomical mapping being done and guidance of insertion into the coronary sinus without any use of contrast. SonoSite ultrasound guidance was also helpful in clearly identifying the veins for initial access without the use of fluoroscopy.
To the best of our knowledge, this is the first case report of near-zero fluoroscopy BiV ICD implantation.
Electroanatomical mapping has been used by various labs to reduce and in some cases eliminate the use of fluoroscopy for various ablation procedures. Currently, electroanatomical mapping is utilized effectively in our lab in this regard, including for complex ablation procedures such as atrial fibrillation and VT ablations, and we were able do perform them nonfluoroscopically in select cases.6
This technique puts us a step closer to hopefully being able to eliminate or reduce exposure to contrast and fluoroscopy in device implantations, reducing risk to patients and lab personnel, as well as further improving outcomes for patients.
Additional studies will be needed to assess feasibility and safety of electroanatomical mapping in clinical practice. This technique development may prove to be of great value and benefit in multiple clinical applications as outlined above.
- Kenny T. “Implant Procedures.” The Nuts and Bolts of ICD Therapy. Wiley-Blackwell, 2006. pg 28.
- Kenny T. “Implant Procedures.” The Nuts and Bolts of Cardiac Resynchronization Therapy. Wiley-Blackwell, 2006. pg 74-75.
- Gepstein L, Hayem G, Ben-Haim SA. A novel method for fluoroscopic catheter-based electroanatomical mapping of the heart. In vitro and In vivo accuracy results. Circulation 1997;95:1611–1622.
- Del Greco M, Marini M, Bonamassari R. Implantation of a biventricular implantable cardioverter-defibrillator guided by electroanatomical mapping system. Europace 2012;14:107–111.
- Tuzcu V, Kilinc OU. Implantable Cardioverter Defibrillator Implantation without Using Fluoroscopy in a Pregnant Patient. Pacing Clin Electrophysiol 2011 Sep 28. doi: 10.1111/j1540-8159.2011.03221.x
- Mina A. Early Outcome of Atrial Fibrillation Program at Methodist Medical Center of Illinois. EP Lab Digest 2011;11:20-21.