ABSTRACT
Background: Inappropriate sinus tachycardia (IST) is defined as resting heart rate >100 beats/min and average 24-hour heart rate >90 beats/min. It is associated with distressing symptoms and significant loss of quality of life. Drugs are not effective in symptom control of IST in up to 30% of patients. Catheter ablation of the sinus node has a high recurrence rate, and the complications are significant. Recently, a novel hybrid sinus node-sparing ablation approach for IST was described. Objective: The objective of the Hybrid Epicardial and Endocardial Sinus Node Sparing Ablation Therapy for Inappropriate Sinus Tachycardia (HEAL-IST) investigational device exemption trial (NCT05280093) is to evaluate safety and effectiveness of the hybrid sinus node-sparing ablation procedure for the treatment of symptomatic, drug-refractory or drug-intolerant IST. Methods: The HEAL-IST trial is a prospective, multicenter, pivotal, single-arm trial. Up to 142 subjects in up to 40 centers will be treated in the trial with a Bayesian adaptive design. Results: Subjects will be assessed for primary safety through 30 days post-hybrid ablation procedure. The primary effectiveness endpoint will be freedom from IST at 12 months. Freedom from IST will be defined as mean heart rate of ≤90 beats/min or at least a 15% reduction in mean heart rate as compared with baseline, in the absence of new or higher dosage of previously failed medications at a 24-month follow-up assessment. Conclusion: The HEAL-IST trial is the first multicenter trial evaluating hybrid IST ablation in patients with symptomatic IST and refractory or intolerant to drugs. The results of this study will help guide decision making regarding the best management in this population.
ABSTRACT
BACKGROUND: The ideal treatment of inappropriate sinus tachycardia (IST) and postural orthostatic tachycardia syndrome (POTS) still needs to be defined. Medical treatments yield suboptimal results. Endocardial catheter ablation of the sinus node (SN) may risk phrenic nerve damage and open-heart surgery may be accompanied by unjustified invasive risks. METHODS: We describe our first multicenter experience of 255 consecutive patients (235 females, 25.94 ± 3.84 years) having undergone a novel SN sparing hybrid thoracoscopic ablation for drug-resistant IST (n = 204, 80%) or POTS (n = 51, 20%). As previously described, the SN was identified with 3D mapping. Surgery was performed through three 5-mm ports from the right side. A minimally invasive approach with a bipolar radiofrequency clamp was used to ablate targeted areas while sparing the SN region. The targeted areas included isolation of the superior and the inferior caval veins, and a crista terminalis line was made. All lines were interconnected. RESULTS: Normal sinus rhythm (SR) was restored in all patients at the end of the procedure. All patients discontinued medication during the follow-up. After a blanking period of 6 months, all patients presented stable SR. At a mean of 4.07 ± 1.8 years, normal SN reduction and chronotropic response to exercise were present. In the 51 patients initially diagnosed with POTS, no syncope occurred. During follow-up, pericarditis was the most common complication (121 patients: 47%), with complete resolution in all cases. Pneumothorax was observed in 5 patients (1.9%), only 3 (1.1%) required surgical drainage. Five patients (1.9%) required a dual-chamber pacemaker due to sinus arrest > 5 s. CONCLUSIONS: Preliminary results of this multicenter experience with a novel SN sparing hybrid ablation of IST/POTS, using surgical thoracoscopic video-assisted epicardial ablation combined with simultaneous endocardial 3D mapping may prove to be an efficient and safe therapeutic option in patients with symptomatic drug-resistant IST and POTS. Importantly, in our study, all patients had a complete resolution of the symptoms and restored normal SN activity.
