Monitoring Spike Potential and Abrupt Impedance Rise with Concomitant Temperature/Contact Force Change for Timely Detection of the Occurrence of “Silent” or “Nonaudible” Steam Pop
Table 2
Comparison of RFCA parameters between audible steam pop group and control group during pulmonary vein isolation (power: 35–40 W).
Audible steam pop group (N = 15)
Control group (N = 15)
t/Z/χ2 value
value
Time from RFCA initiation to occurrence of audible steam pop (s)
19.4 ± 6.9
31.7 ± 5.0#
5.610
<0.001
AI prior to audible steam pop
392.4 ± 87.1
485.0 ± 28.6#
3.914
<0.001
Maximum temperature preceding steam pop (°C)
38.8 ± 2.0
38.0 ± 2.4
1.022
0.315
Minimum temperature preceding steam pop (°C)
34.5 ± 1.7
31.5 ± 2.1
4.273
<0.001
Mean temperature preceding steam pop (°C)
36.2 ± 1.6
35.7 ± 2.3
1.143
0.267
Maximum impedance preceding steam pop (Ω)
127.2 ± 11.9
119.8 ± 6.9
2.090
0.046
Minimum impedance preceding steam pop (Ω)
106.4 ± 8.9
111.6 ± 6.1
1.663
0.090
Mean impedance preceding steam pop (Ω)
117.0 ± 10.3
115.2 ± 5.7
0.590
0.561
Impedance drop preceding steam pop (Ω)
20.8 ± 9.5
8.2 ± 4.1
4.753
<0.001
Maximum CF preceding steam pop (g)
17.7 ± 4.1
13.6 ± 3.9
3.288
<0.001
Minimum CF preceding steam pop (g)
5.6 ± 3.6
3.6 ± 3.6
2.598
0.009
Mean CF preceding steam pop (g)
11.3 ± 2.6
7.7 ± 1.6
3.517
<0.001
Values are given as mean ± SD. #RF parameters without steam pop. Nonnormally distributed data. RFCA = radiofrequency catheter ablation; CF = contact force; AI = ablation index.
