The use of half normal saline during catheter ablation of typical atrial flutter has no impact on the time to achieve bidirectional block
Bibliographic record
Abstract
Abstract Background Achieving bidirectional block (BB) is generally considered to be the endpoint in the ablation of typical atrial flutter (AFL), however acute reconnection is common. Recent data suggest that deeper ablation lesions may be created by decreasing the irrigant ionic concentration using half normal saline (HNS) delivered through an open irrigated ablation catheter compared with normal saline (NS). We sought to assess whether the use of HNS was associated with a more rapid achievement of BB and less reconnections compared with NS. Methods Patients were randomly allocated to catheter ablation with either NS or HNS using a 4-mm irrigated catheter at a power setting of 30 W. Ablation approach employing either a maximum voltage guided (MVG) or empiric cavo-tricuspid isthmus (CTI) line was performed aiming for BB that was confirmed by double potentials separated by an isoelectric line measuring ≥110 ms and evidence of conduction block using differential pacing. Study was powered to an endpoint of acute reconnection within 30 mins. Results A total of 60 patients underwent catheter ablation for typical AFL with either HNS (n=30) or NS (n=30). There were no significant differences between the two groups in terms of patient age (68±7 yrs HNS vs. 68±10 yrs NS) and BMI (31±7 HNS vs 31±5 NS). BB was achieved in all patients. The MVG approach was employed in 28/60 patients. Acute reconnection was observed in 11 patients (18%); 4 in HNS vs 7 in NS group (ns). The mean RF time to achieve BB was 386±262 seconds in HNS vs 456±270 seconds in NS (p=0.21). The approach to CTI ablation showed a significant difference in time to BB: Time to block in MVG cases was 264±143 seconds vs 567±273 in empiric CTI line cases. Figure 1 demonstrates the time to block in both approaches with the choice of irrigant not appearing to impact the time to BB. There were 4 steam pops in the HNS arm and 0 steam pops observed in the NS arm. There were no significant complications in either arm. Conclusion Irrigation with HNS resulted in no statistically significant reduction in duration of RF time or improvement in acute outcomes over NS in the atrial flutter population. Reduction in duration of RF time was driven by MVG approach. However, acute reconnections were higher in NS group, all 4 steam pops occurred in HNS arm. Figure 1 Funding Acknowledgement Type of funding source: None
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".