Abstract
Background: Unipolar electrograms (uni-EGMs) are an essential part of intracardiac mapping. Although Wilson central terminal (WCT) is conventionally used as a reference for signals, avoidance of contamination by far-field and nonphysiologic signals is challenging. Objective: The aim of the study was to explore the impact of an intracardiac indifferent reference electrode close to the recording electrodes, in lieu of WCT, on electrograms. Methods: Sinus node activation was mapped in patients undergoing catheter ablation by a multielectrode array with a close indifferent electrode (CIE) embedded in the distal end of the catheter shaft. An equal number of points was sequentially acquired at each site with use of CIE as a reference first and subsequently with WCT. Uni-EGMs, bipolar EGMs, and the earliest activation area (defined as the area activated in the first 10 ms of the beat) were compared between CIE- and WCT-based activation maps. Results: Seventeen patients (61 ± 18 years; 76% male) were studied. Uni-EGM voltages acquired with CIE were significantly larger than (n = 11) or comparable to (n = 4) those acquired with WCT. When points from the entire cohort were analyzed altogether, unipolar voltages and their maximum negative dV/dT and bipolar voltages recorded with CIE were significantly larger than those recorded with WCT (2.36 [1.42–3.79] mV vs 1.96 [1.25–3.03] mV, P < .0001; 0.40 [0.18–0.77] mV/s vs 0.35 [0.15–0.71] mV/s, P < .0001; and 1.46 [0.66–2.81] mV vs 1.33 [0.54–2.64] mV, P < .0001, respectively). The earliest activation area was significantly smaller in CIE-based activation maps than in WCT-based ones (0.3 [0.7–1.4] cm2 vs 0.6 [1.0–1.8] cm2, P = .01). Conclusion: CIE-based maps were associated with an approximately 20% increase in unipolar voltage and may highlight the origin of a focal activation more clearly than WCT-based ones.
Original language | English |
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Pages (from-to) | 1382-1389 |
Number of pages | 8 |
Journal | Heart Rhythm |
Volume | 21 |
Issue number | 8 |
DOIs | |
State | Published - Aug 2024 |
Externally published | Yes |
Keywords
- Bipolar
- Electrograms
- Mapping
- Unipolar
- Voltage