Table 2. Overview of the outcomes for all irradiated animals and the sham group.
| Animal # | AV junction ablation Dose (Gy) | Mapping Outcome (cm2)–tag points with Voltage ≤ 0.3 mV | Macroscopic Lesion Surface (cm2) | Macroscopic Lesion | Lesion in Histology | ∆Wenckebach end Follow-up (ms) | Follow-up (weeks) |
|---|---|---|---|---|---|---|---|
| 1 | 55¥ | 2.9 | 2.5 | Yes | Yes | n.a. 3° AVB | 24.3 |
| 2 | 55 | 0 | 1.7¶ | Yes¶ | ¶ | 10 | 24.2 |
| 3 | 55 | † | 0 | † | † | † | 12.4 |
| 4 | 40¥ | 1.3 | 1.0 | Yes | Yes | 310 | 24.3 |
| 5 | 40 | † | 0 | † | † | † | 11.6 |
| 6 | 40 | † | 0 | † | † | † | 16.0 |
| 7 | 25 | 0 | 0 | No | Yes | 10 | 24.4 |
| 8 | 25 | 0 | 0.6 | No | Yes | 50 | 24.3 |
| 9 | Sham-group | 0 | 0 | No | No | 10 | 14.7 |
| 10 | Sham-group | 0 | 0 | No | No | 10 | 14.7 |
| 11 | Sham-group | 0 | 0 | No | No | 10 | 26.7 |
| RSPV-LA junction Dose (Gy) | ∆Voltage (mV) Endocardial Tag Points RSPV-LA junction | Hyperechoic on TTE/ICE | Macroscopic Lesion | Lesion in Histology | ∆Wenckebach end Follow-up (ms) | Follow-up (weeks) | |
| 12 | 40 | −1.7*** †† | Yes | Yes | Yes | −5 | 24.4 |
| 13 | 40 | −0.8* ¥¥ | Yes | No | Yes | 10 | 24.4 |
| 14 | 30 | −0.6* ¶¶ | Yes | No | Yes | 5 | 24.6 |
| LV freewall Dose (Gy) | ∆Mean LV-Target Endocardial Voltage (mV) | Abnormal or Double Potentials Endo-/Epicardial (#tags) | Macroscopic Lesion | Lesion in Histology | Hyperechoic on TTE/ICE | Follow-up (weeks) | |
| 15 | 40 | −0.5 ‡‡ | −/10 | Yes | Yes | Yes | 12.6 |
| 16 | 40 | −0.6 ††† | −/− | Yes | Yes | Yes | 12.6 |
| 17 | 40 | −3.4 *** ¥¥¥ | 19/- | Yes | Yes | Yes | 24.6 |
Upper row: anmals irradiated at the atrioventricular junction. Middle row: outcome for animals irradiated at the left atrial right superior pulmonary vein junction. Lower row: outcome for animals irradiated at the left ventricular freewall. n.a. 3° AVB = not applicable due to complete atrioventricular block. TTE = transthoracic echocardiography; ICE = intracardiac echocardiography; † = Deceased from device-related infection; ¥ = Complete AV block seventeen weeks after irradiation on surface ECG. ¶Lesion misplaced into the posterior left ventricular outflow tract. ∆Wenckebach describes the difference in the Wenckebach-block cycle length occurrence for the baseline and follow-up study. Two-sided t-test for comparison of mean voltage at the target position at baseline versus the mean at follow-up date. *p < 0.05; ***p < 0.0001. The following numbers state n of endocardial tag points included into the statistical test. ††n = 518; ¥¥ n = 529; ¶¶n = 315; ‡‡n = 408; †††n = 337; ¥¥¥n = 391.