Computer simulation study on the effect of electrode–tissue contact force on thermal lesion size in cardiac radiofrequency ablation

Figures & data

Figure 1. The geometry of computational model (not to scale).

Table 1. Thermal and electrical characteristics of the elements of the numerical models.

Element/material	$\sigma$ (s/m)	$\lambda$ (W/m·T)	$\rho$ (kg/m^3)	$c$ (J/kg·T)
Electrode	4.6 × 10^6	71	21,500	132
Plastic probe	10^−5	0.026	70	1045
Cardiac tissue	0.54	0.53	1060	3111
Blood	0.99	0.54	1000	4180
Pericardial fluid	1.35	0.628	980	4184

Measurement temperature at 37 °C.

Figure 2. Mechanical, electrical and thermal boundary conditions.

Figure 3. The deformation of cardiac tissue and the displacement field distributions. (A) F = 2 g, (B) F = 5 g, (C) F = 10 g, (D) F = 20 g, (E) F = 30 g, (F) F = 40 g.

Figure 4. Maximum displacement in y direction vs. contact force.

Figure 5. The distribution of electric field intensity, current density, and power density.

Figure 6. Temperature distribution at different CF. (A) F = 2 g, V = 50 V, t = 30 s, (B) F = 5 g, V = 50 V, t = 30 s, (C) F = 10 g, V = 50 V, t = 30 s, (D) F = 20 g, V = 50 V, t = 30 s, (E) F = 30 g, V = 50 V, t = 30 s, (F) F = 40 g, V = 50 V, t = 30 s.

Figure 7. (A) Max temperature of myocardium, (B) lesion area vs ablation time, (C) Myocardial impedance vs ablation time, (D) power vs ablation time.

Figure 8. (A) Lesion depth vs ablation time, (B) lesion width vs ablation time, (C) max lesion depth vs contact force, (D) max lesion width vs contact force.

Table 2. Maximum myocardial temperature, impedance change, lesion cross-section area, lesion depth, and lesion width at different CF values.

Ablation modes	2 g	5 g	10 g	20 g	30 g	40 g
Max tissue temp(°C)	86.6	89.2	91.7	94.2	95.6	96.6
Impedance change(Ω)	5.13	6.10	7.12	8.34	9.10	9.61
Lesion cross-section area (mm²)	16.05	20.62	24.98	30.32	33.65	36.04
Lesion depth(mm)	3.56	3.99	4.43	4.97	5.28	5.52
Lesion width(mm)	5.69	5.6	7.24	8.00	8.39	8.68