Long-term outcomes of sinus node modification in patients with severely symptomatic drug-refractory inappropriate sinus tachycardia: a single-center experience

Background: The purpose of the study was to evaluate the long-term outcomes of sinus node modification (SNM) in treating patients with severely symptomatic drug-refractory inappropriate sinus tachycardia (IST). Methods: The study included 39 patients with symptomatic drug-refractory IST who have undergone SNM at Saint Louis University Hospital. Data was reviewed retrospectively. Recurrence of symptoms was assessed at 3–6-month follow-up intervals. Results: The mean age of our cohort was 31.5 ± 11. The mean HR at diagnosis was 135 ± 25.4 beats per minute (BPM). Thirty-seven of 39 (94.8%) patients had complete resolution of symptoms. Of these 37 patients, 16 required 1 SNM, 17 patients required 2 SNM, and 4 patients required 3 SNM in order to achieve complete symptom resolution. Mean HR post-procedure was 78.6 ± 12.3 BPM. Thirteen of 39 patients required rate control medication post-procedure, all of whom were prescribed beta-blockers. Patients were followed every 3 to 6 months with a mean follow-up duration of 62.3 ± 42.9 months from the patient’s last SNM procedure. Thirteen of those 37 patients (35.1%) developed intermittent symptomatic bradycardia requiring permanent pacemaker implantation. Two of the 39 patients had phrenic nerve injury, and 6 patients had post-procedure pericarditis. Conclusions: This study provides additional information to the limited dataset available in the literature and shows that SNM might provide patients with long-term symptomatic relief bearing in mind the potential increased risk for the need for permanent pacing.