1 Introduction
2 Methods
2.1 Heart muscle surface flattener and preparation
2.2 Radiofrequency ablation system incorporating the catheter angle setter and contact force sensor
2.3 Ablation parameters
Parameters | |
---|---|
Ablation time, s | 30 |
Power, W | 30 |
Ablation temperature, °C | 30 |
Saline tank temperature, °C | 35–37 |
Initial irrigation rate, mL/min | 2 |
Ablation irrigation rate, mL/min | 17 |
Catheter contact force, gf | 2, 4, 6, 10, 15, 20, 30, and 40 |
Catheter contact angle, deg | 0, 30, 45, 60, and 90 |
2.4 Evaluation of ablation lesion dimensions and comparison of catheter contact area with ablation lesion area
2.5 Statistical analysis
3 Results
Contact force | Contact angle | ||||
---|---|---|---|---|---|
0 deg | 30 deg | 45 deg | 60 deg | 90 deg | |
2 gf | 16.67 ± 1.63 | 16.46 ± 3.00 | 12.93 ± 1.13 | 9.05 ± 1.79 | 13.28 ± 1.49 |
4 gf | 24.17 ± 4.14 | 21.58 ± 2.94 | 19.98 ± 0.68 | 19.07 ± 3.43 | 18.53 ± 1.46 |
6 gf | 24.05 ± 3.46 | 23.81 ± 1.40 | 19.76 ± 3.06 | 20.52 ± 2.23 | 17.09 ± 3.10 |
10 gf | 35.54 ± 1.59 | 37.35 ± 3.88 | 21.70 ± 2.24 | 20.99 ± 0.79 | 21.89 ± 1.90 |
15 gf | 37.81 ± 2.87 | 34.23 ± 3.98 | 24.01 ± 0.65 | 23.26 ± 3.55 | 19.55 ± 0.87 |
20 gf | 36.10 ± 3.18 | 28.90 ± 6.62 | 32.59 ± 4.58 | 30.41 ± 6.69 | 22.78 ± 3.84 |
30 gf | 38.04 ± 6.07 | 40.60 ± 6.78 | 35.37 ± 5.39 | 33.44 ± 3.79 | 29.85 ± 1.46 |
40 gf | 44.10 ± 3.50 | 40.33 ± 6.90 | 39.38 ± 5.82 | 41.87 ± 5.68 | 37.62 ± 7.27 |
Contact force | Contact angle | ||||
---|---|---|---|---|---|
0 deg | 30 deg | 45 deg | 60 deg | 90 deg | |
2 gf | 1.98 ± 0.30 | 1.70 ± 0.23 | 1.92 ± 0.39 | 2.20 ± 0.40 | 3.68 ± 0.38 |
4 gf | 1.90 ± 0.14 | 2.02 ± 0.36 | 2.14 ± 0.20 | 2.31 ± 0.32 | 4.16 ± 0.47 |
6 gf | 2.50 ± 0.32 | 2.23 ± 0.28 | 2.49 ± 0.22 | 3.10 ± 0.66 | 4.25 ± 0.33 |
10 gf | 3.43 ± 0.53 | 3.43 ± 0.43 | 3.04 ± 0.45 | 3.80 ± 0.45 | 4.49 ± 0.38 |
15 gf | 3.74 ± 0.40 | 3.40 ± 0.62 | 3.46 ± 0.77 | 4.76 ± 0.65 | 5.89 ± 0.61 |
20 gf | 4.09 ± 0.43 | 4.16 ± 0.55 | 3.78 ± 0.54 | 4.45 ± 0.56 | 5.80 ± 0.50 |
30 gf | 4.10 ± 0.21 | 4.26 ± 0.58 | 5.56 ± 0.48 | 5.48 ± 0.60 | 6.31 ± 0.68 |
40 gf | 4.76 ± 0.36 | 5.54 ± 0.42 | 5.75 ± 0.57 | 5.68 ± 0.47 | 7.53 ± 0.33 |
3.1 Relationships between ablation lesion area, catheter contact force, catheter contact angle, and catheter contact area
Contact angle (deg) | Lesion area | Lesion depth | ||||
---|---|---|---|---|---|---|
P value | Significantly different (P < 0.05)? | P value | Significantly different (P < 0.05)? | |||
0 | vs | 30 | 0.1928 | No | 0.8186 | No |
vs | 45 | 0.0062 | Yes | 0.4129 | No | |
vs | 60 | 0.0036 | Yes | 0.0025 | Yes | |
vs | 90 | 0.0011 | Yes | < 0.0001 | Yes | |
30 | vs | 45 | 0.0605 | No | 0.3735 | No |
vs | 60 | 0.0378 | Yes | 0.0063 | Yes | |
vs | 90 | 0.0037 | Yes | < 0.0001 | Yes | |
45 | vs | 60 | 0.2331 | No | 0.0291 | Yes |
vs | 90 | 0.0342 | Yes | < 0.0001 | Yes | |
60 | vs | 90 | 0.1244 | No | < 0.0001 | Yes |
Contact angle | Contact force (gf) | |||||||
---|---|---|---|---|---|---|---|---|
2 | 4 | 6 | 10 | 15 | 20 | 30 | 40 | |
0 deg | 1.46 | 2.23 | 2.28 | 2.53 | 2.45 | 2.35 | 2.32 | 2.31 |
30 deg | 2.74 | 2.91 | 3.00 | 3.89 | 2.60 | 1.97 | 3.45 | 2.73 |
45 deg | 1.83 | 2.84 | 1.94 | 2.07 | 2.03 | 2.54 | 2.38 | 2.04 |
60 deg | 1.95 | 2.63 | 2.51 | 2.08 | 2.09 | 2.66 | 2.76 | 3.10 |
90 deg | 3.86 | 4.22 | 3.04 | 3.18 | 2.34 | 3.08 | 3.14 | 2.99 |
3.2 Relationships between catheter contact force, catheter contact angle, and ablation lesion depth
4 Discussion
4.1 Major findings
4.2 Correlation between catheter contact area and ablation lesion area
Pearson’s coefficient (r)* | Correlation level** | |
---|---|---|
Contact force vs. lesion area | ( +) 0.7816 | Strong |
Contact angle vs. lesion area | ( −) 0.3688 | Weak |
Contact area vs. lesion area | ( +) 0.8507 | Very strong |
Contact force vs. lesion depth | ( +) 0.7807 | Strong |
Contact angle vs. lesion depth | ( +) 0.4550 | Moderate |
Angle (deg) | Lesion area approximation formula | R2 | Contact area approximation formula | R2 |
---|---|---|---|---|
0 | Y = 2.413X − 0.8227 | 0.9653 | X = 2.685ln(Z) + 7.782 | 0.837 |
30 | Y = 2.723X + 1.791 | 0.8799 | X = 3.036ln(Z) + 3.465 | 0.845 |
45 | Y = 2.079X + 1.395 | 0.8717 | X = 3.689ln(Z) + 2.952 | 0.867 |
60 | Y = 3.232X – 6.825 | 0.8709 | X = 2.807ln(Z) + 3.137 | 0.984 |
90 | Y = 2.601X + 4.486 | 0.9691 | X = 2.693ln(Z) + 0.892 | 0.893 |
4.3 Correlation between catheter contact force, ablation lesion area, and lesion depth
Contact angle (deg) | Contact force vs. lesion area | Contact force vs. lesion depth | ||||
---|---|---|---|---|---|---|
Logarithmic (R2) | Linear (R2) | Behavior of the correlation | Logarithmic (R2) | Linear (R2) | Behavior of the correlation | |
0 | 0.7828 | 0.6484 | Log | 0.8481 | 0.7538 | Log |
30 | 0.6203 | 0.5181 | Log | 0.8573 | 0.8256 | Log |
45 | 0.8392 | 0.8107 | Log | 0.8636 | 0.8761 | Linear |
60 | 0.8161 | 0.8000 | Log | 0.8355 | 0.7524 | Log |
90 | 0.7232 | 0.7921 | Linear | 0.8280 | 0.8377 | Linear |