Catheter Ablation of Atrial Fibrillation: Current and Evolving Indications

Impact of weight adjusted high frequency low tidal volume ventilation and atrial pacing in lesion metrics in high-power short-duration ablation: Results of a pilot study

INTRODUCTION

Lesion size index (LSI) was introduced with the use of Tacticath™ and as a surrogate of lesion quality. The metric used to achieve the predetermined values involves combined information of contact force (CF), power and radiofrequency time. Rapid atrial pacing (RAP) and high-frequency low-tidal volume ventilation (HFLTV) independently or in combination improve catheter stability and CF and quality of lesions. Data of the impact of body weight adjusted HFLTV ventilation strategy associated with RAP in the lesion metrics still lacking. The study aimed to compare the results of high-power short-duration (HPSD) atrial fibrillation ablation using simultaneous weight adjusted HFLTV and RAP and standard ventilation (SV) protocol.

METHODS

Prospective, nonrandomized study with 136 patients undergoing de novo ablation divided into two groups; 70 in RAP (100 ppm) + HFLTV with 4 mL/kg of tidal volume and 25 breaths/min (group A) and 66 patients with SV in intrinsic sinus rhythm (group B). Ablation using 50 W, CF of 5-10 g/10-20 g and 40 mL/minute flow rate on the posterior and anterior left atrial wall, respectively.

RESULTS

No procedure-related complications. Group A: Mean LSI points 70 ± 16.5, mean total lower LSI 3.4 ± 0.5, mean total higher LSI 8.2 ± 0.4 and mean total LSI 5.6 ± 0.6. Anterior and posterior wall mean total LSI was 6.0 ± 0.4 and 4.2 ± 0.3, respectively. Mean local impedance drop (LID) points were 118.8 ± 28.4, mean LID index (%) 12.9 ± 1.5, and mean LID < 12% points 55.9 ± 23.8. Anterior and posterior wall mean total LID index were 13.6 ± 2.0 and 11.9 ± 1.7, respectively. Recurrence in 11 (15.7%) patients. Group B: Mean LSI points 56 ± 2.7, mean total lower LSI 2.9 ± 0.7, mean total higher LSI 6.9 ± 0.9, and mean total LSI 4.8 ± 0.8. Anterior and posterior wall mean total LSI was 5.1 ± 0.3 and 3.5 ± 0.5, respectively. Mean LID points were 111.4 ± 21.5, mean LID index (%) 11.4 ± 1.2, and mean LID < 12% points 54.9 ± 25.2. Anterior and posterior wall mean total LID index were 11.8 ± 1.9 and 10.3 ± 1.7, respectively. Recurrence in 14 (21.2%) patients. Mean follow up was 15.2 ± 4.4 months.

CONCLUSION

Weight adjusted HFLTV ventilation with RAP HPSD ablation produced lower recurrence rate and better LSI and LID parameters in comparison to SV and intrinsic sinus rhythm.

Atrial Fibrillation Burden: Impact on Stroke Risk and Beyond

Atrial fibrillation (AF) is an important independent risk factor for stroke. Current guidelines handle AF as a binary entity with risk driven by the presence of clinical risk factors, which guides the decision to treat with an oral anticoagulant. Recent studies in the literature suggest a dose-response relationship between AF burden and stroke risk, in both clinical AF and subclinical atrial fibrillation (SCAF), which differs from current guidance to disregard burden and utilize clinical risk scores alone. Within clinical classification and at the same risk levels in various scores, the risk of stroke increases with AF burden. This opens the possibility of incorporating burden into risk profiles, which has already shown promise. Long-term rhythm monitoring is needed to elucidate SCAF in patients with stroke. Recent data from randomized trials are controversial regarding whether there is an independent risk from AF episodes with a duration of less than 24 h, including the duration of SCAF greater than six minutes but less than 24 h.

Impact of Frailty on Clinical Outcomes in Patients With Atrial Fibrillation Who Underwent Cardiac Ablation Using a Nationwide Database

This study aimed to assess the association between frailty and clinical outcomes in patients with atrial fibrillation (AF) who undergo catheter ablation. We conducted a retrospective cohort study using the National Inpatient Sample database from 2017 to 2019. Adult patients hospitalized with a primary diagnosis of AF who underwent catheter ablation were included. Frailty was assessed using the Hospital Frailty Risk Score. The primary outcome was the presence of any complication (vascular, cardiac, respiratory, neurologic, or infectious), and secondary outcomes were in-hospital mortality, length of hospital stay, and hospital charges. A total of 21,075 weighted hospitalizations were included, and 14% were classified as intermediate or great risk of frailty. Patients with intermediate (adjusted relative risk 2.86, 95% confidence interval 2.24 to 3.67) and great (adjusted relative risk 6.68, 95% confidence interval 3.77 to 11.84) risk of frailty were associated with a greater risk of any complication than that of the group at less risk. The in-hospital mortality rate was significantly higher among patients at intermediate risk than among those at less risk of frailty (2.6% vs 0.1%, p <0.001). Patients with great and intermediate risk had significantly longer hospital stays than did the group with less risk (median 14 vs 5 vs 2 days, p <0.001), in addition to greater total charges (median $189,072 vs $161,598 vs $130,672, p <0.001), respectively. In conclusion, frailty was associated with a greater risk of poor short-term outcomes in patients with AF who underwent catheter ablation. The Hospital Frailty Risk Score is a useful tool for identifying patients at increased risk of adverse events and could aid in preoperative optimization and postoperative management.

Comparison between weight-adjusted, high-frequency, low-tidal-volume ventilation and atrial pacing with normal ventilation in high-power, short-duration atrial fibrillation ablation: Results of a pilot study

Background

Better contact force (CF) and catheter stability (CS) during atrial fibrillation (AF) ablation are associated with higher success rate. Changes in CF and CS are observed during respiratory movements and cardiac contraction. Previous studies have suggested that rapid atrial pacing (RAP) and high-frequency, low-tidal-volume ventilation (HFLTV) independently or in combination improve CS and CF and quality of lesions. Data from a body weight-adjusted HFLTV strategy associated with RAP in AF high-power, short-duration (HPSD) ablation are still lacking.

Objective

This study aimed to compare the results of HPSD AF ablation using simultaneous weight-adjusted HFLTV and RAP and standard ventilation (SV) protocol.

Methods

This was a prospective, nonrandomized study with 136 patients undergoing de novo ablation were divided into 2 groups: 70 in RAP (100 ppm) + HFLTV with 4 mL/kg of tidal volume and 25 breaths/min (group A) and 66 patients with SV in intrinsic sinus rhythm (group B). The ablation used 50 W, CF of 5 to 10 g and 10 to 20 g, and 40 mL/min flow rate on the posterior and anterior left atrial walls, respectively.

Results

There were no procedure-related complications. In group A, left atrial and total ablation times were 53.5 ± 8.3 minutes and 67.4 ± 10.1 minutes, respectively. Radiofrequency time was 19.7 ± 5.7 minutes, radioscopy time was 3.4 ± 1.8 minutes, 62 (88.6%) patients had first-pass isolation, 23 (33.3%) patients had elevation of luminal esophageal temperature, and 7 (10%) patients had recurrence. In group B, left atrial time was 56.7 ± 10.8 minutes, total ablation time was 72.4 ± 11.5 minutes, radiofrequency time was 22.4 ± 6.2 minutes, radioscopy time was 3.6 ± 3 minutes, 58 (87.9%) patients had first-pass isolation, and 20 (30.3%) patients had luminal esophageal temperature elevation.

Conclusion

Weight-adjusted HFLTV with RAP in comparison with SV and intrinsic sinus rhythm in HPSD ablation is safe with no CO2 retention. The approach produced significantly reduced radiofrequency, left atrial, and total ablation times and better CF and local impedance drop indexes.