Author + information
- Received April 28, 2017
- Revision received May 26, 2017
- Accepted June 9, 2017
- Published online September 13, 2017.
- Ammar M. Killu, MBBS,
- Deepak Padmanabhan, MBBS,
- Kalpathi L. Venkatachalam, MD and
- Samuel J. Asirvatham, MD∗ ()
- Department of Cardiovascular Diseases and Department of Pediatric & Adolescent Medicine, Mayo Clinic, Rochester, Minnesota
- ↵∗Address for correspondence:
Dr. Samuel J. Asirvatham, Department of Cardiovascular Diseases and Department of Pediatric & Adolescent Medicine, Mayo Clinic, 200 First Street Southwest, Rochester, Minnesota 55905.
Catheter stability and adequate tissue contact are recognized as being fundamental to achieving favorable outcomes in ablation procedures. Conversely, excessive contact is associated with procedural complications. At present, electrogram amplitude and impedance are poor predictors of electrode-tissue contact force (CF) for ablation.
Because current systems have limited dynamic range and bandwidth, signal saturation occurs. We hypothesized that increased dynamic range, increased sampling rate, and wider bandwidth (PURE-EP, BioSig Technologies, Minneapolis, Minnesota) improves signal acquisition/display and would be capable of demonstrating current of injury on the local electrogram. As such, we performed unipolar/bipolar intracardiac mapping using a Smart-Touch catheter (Biosense Webster, Baldwin Park, California) to obtain CF measurements while simultaneously recording signals comparing PURE-EP (0.05 to 1 kHz; 24-bit analog/digital conversion; 2,000 samples/s sampling rate; low gain with no saturation in ± 250 mV range) with a standard recording system (0.05 to 500 Hz, 12-bit analog/digital conversion, 977 samples/s sampling rate).
PURE-EP clearly demonstrated current of injury on the local unipolar electrogram, consistent with catheter electrode-tissue contact. Furthermore, the current of injury amplitude change was related to CF as measured by the Smart-Touch catheter (Figure 1A). The wide bandwidth precluded saturation while the high dynamic range and sampling rate provided good temporal resolution such that changes in CF (Figure 1B) correlated with changes in the local unipolar electrogram (Figure 1C).
Although this is a preliminary proof of concept study that requires further validation, analysis of the local electrogram with PURE-EP may help determine adequate electrode contact thus improving lesion formation while reducing procedural complications. It should be noted that different tissues might demonstrate different amounts of ST segment change depending on their characteristics. Further study is required before use of ST segment changes can be truly correlated to CF.
Dr. Asirvatham is a consultant for BioSig. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- Received April 28, 2017.
- Revision received May 26, 2017.
- Accepted June 9, 2017.
- 2017 American College of Cardiology Foundation