Sinus node sparing hybrid thoracoscopic ablation for inappropriate sinus tachycardia

Sinus node sparing hybrid thoracoscopic ablation for inappropriate sinus tachycardia

Surgical and radiofrequency ablations for drug refractory inappropriate sinus tachycardia (IST) have been hitherto not very satisfactory, though various approaches have been tried. Sinus node sparing hybrid thoracoscopic ablation was described as a novel approach in 2019 for both IST and postural orthostatic tachycardia (POTS) [1]. Video assisted thoracoscopic ablation was performed through three 5 mm ports from the right side. A radiofrequency bipolar clamp was utilized for isolation of both superior and inferior vena cava and a crista terminalis line was made, with sparing of sinus node. All lines were interconnected.

Of the 50 patients in that seminal study, 39 had IST and 11 had POTS. All patients had stable sinus rhythm after a 6 months blanking period, with complete resolution of symptoms. At a mean follow up period of 28.4 months, normal sinus node function and chronotropic response to exercise was noted. Pericarditis was the commonest complication, which occurred in 39 patients, with complete resolution in all cases. In the hybrid approach, sinus node was identified with concomitant endocardial 3D mapping.

After the promising results of the initial report, a prospective multicenter registry compared sinus node sparing hybrid ablation with radiofrequency sinus node modification [2]. There were 50 patients in each group, with a mean age of 22.8 years. The hybrid procedure was done as described in the previous study. Radiofrequency sinus node modification was done by endocardial and/or epicardial mapping and ablation at the site of earliest atrial activation. Normal sinus rhythm and rate was restored in all patients in the hybrid group and 84% of the sinus node modification group. Hybrid ablation had better improvement in mean daily heart rate and peak 6 minute walk heart rate compared with sinus node modification. Redo procedures were needed in all the sinus node modification group compared to 8% in the hybrid group. Phrenic nerve injury occurred in 14% of the sinus node modification group, but none in the hybrid ablation group. Acute pericarditis occurred in 92% of the sinus node modification group and 48% of the hybrid ablation group. Permanent pacemaker implantation was needed in half of the sinus node ablation group and 4% of the hybrid ablation group.

Another multicenter experience of 255 patients had been reported in 2021 [3]. Like the initial study, that study also included patients with IST and POTS. It had included 204 cases of drug resistant IST and 51 cases of POTS. Procedure was hybrid ablation as described initially. Mean age of patients was 25.94 years in that study and all underwent sinus node sparing hybrid thoracoscopic ablation. All patients had stable sinus rhythm at the end of the procedure and discontinued medications during follow up. At a mean follow up of about 4 years normal chronotropic response to exercise was present. Pericarditis was the commonest complication, noted in 47%, with complete resolution. Five patients required dual chamber pacemaker for sinus arrest lasting more than 5 seconds.

Overall, the results of sinus node sparing hybrid thoracoscopic ablation for inappropriate sinus tachycardia appears promising. As of now we have only non-randomized study data. We need randomized controlled trials before a firm recommendation can be made on this novel treatment option. Still, it is likely to be considered as a viable option for drug refractory IST if other studies document the good results which are sustainable in the long term.

References

1. de Asmundis C, Chierchia GB, Sieira J, Ströker E, Umbrain V, Poelaert J, Brugada P, La Meir M. Sinus Node Sparing Novel Hybrid Approach for Treatment of Inappropriate Sinus Tachycardia/Postural Orthostatic Sinus Tachycardia With New Electrophysiological Finding. Am J Cardiol. 2019 Jul 15;124(2):224-232. doi: 10.1016/j.amjcard.2019.04.019. Epub 2019 Apr 23. PMID: 31084999.
2. Lakkireddy D, Garg J, DeAsmundis C, LaMeier M, Romeya A, Vanmeetren J, Park P, Tummala R, Koerber S, Vasamreddy C, Shah A, Shivamurthy P, Frazier K, Awasthi Y, Chierchia GB, Atkins D, Bommana S, Di Biase L, Al-Ahmad A, Natale A, Gopinathannair R. Sinus Node Sparing Hybrid Thoracoscopic Ablation Outcomes in Patients with Inappropriate Sinus Tachycardia (SUSRUTA-IST) Registry. Heart Rhythm. 2022 Jan;19(1):30-38. doi: 10.1016/j.hrthm.2021.07.010. Epub 2021 Jul 30. PMID: 34339847.
3. de Asmundis C, Chierchia GB, Lakkireddy D, Romeya A, Okum E, Gandhi G, Sieira J, Vloka M, Jones SD, Shah H, Winner M, Patel D, Whalen SP, Beaty EH, Kincaid EH, Lee A, Brodt C, Taylor BJ, Colombowala I, Romano M, Morady F, Ströker E, Overeinder I, Bala G, Van Meeteren J, Krauthammer Y, Koerber S, Shults C, Thomaides A, Badhwar N, Gopinathannair R, Shah A, Tummala R, Bello D, Hoff S, Almorad A, Frazier K, Brugada P, La Meir M. Sinus node sparing novel hybrid approach for treatment of inappropriate sinus tachycardia/postural sinus tachycardia: multicenter experience. J Interv Card Electrophysiol. 2021 Aug 23. doi: 10.1007/s10840-021-01044-5. Epub ahead of print. PMID: 34424446.