Table 2.
Targeted anatomical location | SVC | RAA | RSPV |
---|---|---|---|
Therapy profile | Low dose (700 V) | High dose (1500 V) | High dose (1500 V) |
Number of ablated locations (n, total) | 6 | 6 | 6 |
Continuous transmurality achieved | 6/6 | 6/6 | 6/6 |
Wall thickness in chronic ablation lesion, average (mm) ± of maximum measurements of all slides SD | 0.47 ± 0.15 (0.232–0.751) | 1.29 ± 0.41 (0.673–2.169) | 2.62 ± 1.56c (0.524–6.514) |
Wall thickness of adjacent unablated (native) tissue, average (mm) ± SD | 0.53 ± 0.23 (0.227–1.017) | 1.76 ± 0.92 (0.792–3.668) | 2.16 ± 1.32 (0.962–4.652) |
Presence of viable myofibers creating cross‐lesional conduits | 0/6 | 0/6 | 0/6 |
Additional intralesional observations beyond expected healinga | 0/6 | 0/6 | 0/6 |
Ablation is complete based on gross and histological observations (n/n)b | 6/6 | 6/6 | 6/6 |
Average temperature rise recorded 1 s post‐delivery | 0.70 ± 0.35°C | 5.00 ± 1.83°C | 4.95 ± 2.52°C |
Abbreviations: RAA, right atrial appendage; RSPV, right superior pulmonary vein; SVC, superior vena cava.
Expected or typical myocardial remodeling after an ablation treatment 4‐week earlier will result in a bulk of uniform replacement fibrosis extending from the application surface into the myocardial wall. The chronic fibrotic tissue will be devoid of major inflammation, calcification, or significant vascular or epicardial/adventitial changes. In cases of endocardial treatments, minor neointima formation is expected.
An ablation is morphologically denoted as “complete” when it is circumferentially transmural along an orifice or around a tubular structure.
All six RSPV ablations extended into right atrial tissues, extending the lesion depths into this adjoining atrial myocardium.