Catheter design, fabrication, and deployment.

The diagnostic recording catheter (AcQMap 3D Imaging and Mapping Catheter) is a single-use device that has a 10-F nondeflectable shaft, an integral handle, and an expandable distal apparatus designed to yield a global examination of a cardiac chamber of interest and acquire data without the need to contact the chamber surface (noncontact mapping). The distal apparatus forms a 25-mm spheroid of 6 splines, each populated with 8 single-element ultrasound transducers and 8 low-impedance, high-fidelity, biopotential electrodes, with a total of 48 of each type of sensor (Figure 4B). The transducers provide distances between the splines and the endocardial surface. The electrodes are engineered for both a small size (~0.8 mm²) and a low impedance to maximize signal-to-noise ratio, preserve baseline flatness, and maximize the fidelity for sensing the cardiac electric field. Body-surface ECG and patch electrodes are placed on the patient to provide ECG signals and localization data to the system. The catheter is deployed in the cardiac chamber of interest through a purpose-built deflectable introducer sheath over a 0.032-inch guidewire (Figure 4C) and ultrasound is activated to measure points of first reflection and reconstruct the endocardial anatomy. A respiration removal filter extracts low-frequency respiration signals from the EGMs and distance vectors. The catheter is connected to a computerized medical instrument (Figure 4A, console and workstation).