Case 1: Selective Endomyocardial Biopsy
A 25-year-old male with a family history of sudden cardiac death in a first-degree relative was noted to have right ventricular (RV) dilatation on echocardiogram. There were no ECG findings of arrhythmogenic right ventricular dysplasia (ARVD) or other repolarization abnormalities. An electrophysiology study was performed consisting of a VT stimulation protocol for risk stratification; this was negative. A geometry of the RV was created using the EnSite Velocity™ Cardiac Mapping System (St. Jude Medical). No obvious aneurysms were noted, but an area of low voltage tissue (<0.5 mV) was identified in the right ventricular outflow tract (RVOT) using a bipolar roving catheter (Figure 1 and Video 1). In order to obtain a representative biopsy of the region, the bioptome was transduced by attaching an alligator clip to the shaft of the biopsy forceps and then to the pin block, linking it with the mapping system (technical details discussed in Case 2).
By doing this, the tip of the bioptome could be visualized with accuracy in relation to the underlying voltage map. The shaft of the forceps had to be insulated by the Mullen’s sheath to minimize the distortion, enabling the bioptome tip to be located by the EnSite Velocity System within the blood pool. To ensure contact with cardiac tissue for the biopsy, the unipolar electrogram could be seen on both the EP recording system and on EnSite Velocity. Three-dimensional lesions could also be added to the RV geometry model at the biopsy sites to document from where the samples were taken.
Case 2: Visualization of the BRK transseptal needle using non-fluoroscopic navigation
The transseptal puncture is usually performed aided by fluoroscopic anatomy. We initially used a double transseptal (TS) technique for pulmonary vein isolation with a two-catheter ablation strategy (multipolar PV catheter and an irrigated tip catheter for point-by-point ablations). We now employ a single TS puncture and then enter the left atrium with the ablation catheter using a guide wire marker through the puncture site.
To locate the TS site can sometimes be challenging and require more substantial fluoroscopic exposure.
In order to minimize fluoroscopy, we performed TS puncture using a standard drop-down technique. However, the BRK Transseptal Needle (St. Jude Medical) was transduced using and linked to the mapping system in order to visualize the needle tip on the interatrial septum.
Alligator clips were attached to the hilt of the BRK needle, while the rest of the needle was insulated by the SL1 sheath (St. Jude Medical). This allowed accuracy in locating the tip of the needle and a “3D” point could then be placed at the puncture site (Figure 3). The ablation catheter, now seen on EnSite Velocity, could be guided to the TS site and into the left atrium without the need for fluoroscopy (Video 2).
Connections for Visualization on the EnSite Velocity System
To make the connections to the EnSite Velocity System in order to be able to see the bioptome or BRK needle, we first used alligator clips connected to the proximal shaft of the bioptome or BRK needle. In the catheter setup menu in EnSite Velocity, we added a generic NEW catheter that was labeled BIO or BRK and color coded. The following catheter settings were employed: number of electrodes set to 2, diameter set to 5F, and distal electrode length was defined as 2 mm with an inter-electrode spacing of 2 mm (Figure 4). Electrodes for the bioptome or BRK needle were assigned on the EnSite Velocity System to the corresponding pin block (Figure 5).
These connections purely derived a unipolar signal from the bioptome or BRK needle, which then could be visualized both on the recording system as well as the mapping system.
Note: This use of EnSite Velocity™ (SJM) system is an off label use, and is not promoted by SJM.
Disclosures: Dr. Ali, Ms. Andress, and Dr. Michael have no conflicts of interest to report regarding the content herein. Ms. McDonell reports she is an employee of St. Jude Medical.