Outcome of High-power Short-duration Radiofrequency Ablation in Combination with Half-Normal Saline Irrigation for the Treatment of Atrial Fibrillation

Systematic use of half normal saline during ablation of ventricular tachycardia in structural heart disease

BACKGROUND

Efficiency and safety of ablation using half normal saline (HNS) has been shown in refractory ventricular tachycardia (VT), but no evaluation in unselected larger populations has been made.

OBJECTIVE

To evaluate the efficiency and safety of systematic HNS ablation in VT ablation.

METHODS

All successive VT ablations in patients with structural heart disease from 2018 to 2021 used HNS in our center and were retrospectively included.

RESULTS

One hundred seventy-seven successive VT ablation procedures using HNS have been performed in 148 patients (91% males, mean 64 ± 12 years, ischemic cardiomyopathy 64%, left ventricular ejection fraction 38 ± 13%). A mean of 19 ± 7.5 min of RF was delivered, with a mean power of 44 ± 7 W. Relevant complications happened in 9% (strokes 2%, tamponades 3%, atrioventricular block during septal ablations 5%). Over a mean follow-up of 15 ± 9 months, VT recurred in 46%. Final recurrence rate after one or several procedures was 36% (18 months follow-up). Number of VT episodes decreased from 14 ± 35 before to 2.5 ± 10 after ablation (p < .0001) and number of ICD shocks decreased from 4.8 ± 6.8 to 1.5 ± 0.8 (p = .027).

CONCLUSION

Systematic use of HNS during VT ablations in patients with structural heart disease leads to long-term recurrences rates and complications in the range of what is reported using normal saline. Although controlled studies are needed for demonstrating the superiority of such attitude, the use of HNS in every scar-related VT ablation seems safe for standard cases and may be furthermore useful in case of refractory arrhythmias due to difficult-to-ablate substrates.

Half-Normal Saline vs Normal Saline for Cavotricuspid Isthmus-Dependent Atrial Flutter Ablation

Background

Cavotricuspid isthmus (CTI) ablation requires permanent bidirectional block to prevent recurrence of typical atrial flutter (AFL). Catheter irrigation with half-normal saline (HNS) produces larger and deeper lesions in experimental models compared with normal saline (NS). This study was performed to compare the clinical efficacy and safety of HNS vs NS irrigation for typical AFL ablation.

Methods

Sixty patients undergoing catheter ablation of typical AFL were randomized 1:1 to NS or HNS irrigation. Endpoints included time to CTI block, acute reconnection, incidence of steam pops, and recurrence of AFL during follow-up.

Results

Baseline characteristics were comparable between both arms. The mean age of the patients was 68.5 ± 8.2 years, 20% were female, and 32% had atrial fibrillation before being enrolled. Bidirectional CTI block was obtained in all patients with no difference in time to CTI block between groups (6.4 ± 4.4 minutes vs 7.6 ± 4.5 minutes, respectively; P = 0.15). There was a trend to less acute reconnection in the HNS group compared with NS (13.3% vs 26.6%; P = 0.46). Steam pops occurred in 4 patients using HNS vs none in the NS group, but no major complications were observed. During the follow-up, rate of AFL recurrence was similar between groups (6.7% with HNS vs 10% with NS; P = 0.5). There was no difference in time to recurrence (7.6 ± 6.9 vs 4.9 ± 4.5 months; P = 0.6).

Conclusions

In this small pilot randomized controlled trial, there was no significant difference between HNS and NS for CTI ablation; however, HNS may increase the incidence of steam pops.

QDOT MICRO™ versus THERMOCOOL® SMARTTOUCH™ and THERMOCOOL SMARTTOUCH® Surround Flow in radiofrequency ablation of paroxysmal atrial fibrillation

Aim: The objective of this study was to indirectly compare QDOT MICRO™ (QDOT), Thermocool® SmartTouch™ (ST) and Thermocool® SmartTouch® Surround Flow (STSF) to treat paroxysmal atrial fibrillation. Methods: Differences in baseline characteristics between study cohorts were reduced by reweighting patients using inverse probability of treatment weighting. The primary outcome was procedure time. Secondary outcomes were fluoroscopy time, clinical success at 12 months, and rhythm monitoring-adjusted recurrence. Results: QDOT was associated with significantly faster mean procedure and fluoroscopy time, and significant improvement in the rate of recurrence compared with pooled ST/STSF. No difference was observed for clinical success at 12 months. Conclusion: QDOT was associated with greater efficiency, greater effectiveness in rhythm monitoring-adjusted recurrence and similar effectiveness in clinical success at 12 months compared with pooled ST/STSF.