Long-term follow-up of minimally invasive video-assisted thoracoscopic surgery with epicardial radiofrequency ablation for complex cases of inappropriate sinus tachycardia

Introduction Inappropriate sinus tachycardia (IST) is a rare disorder defined as a nonparoxysmal rhythm originating from the sinus node associated with palpitations with a resting heart rate 4100 beats/min and a 24-hour mean heart rate 490 beats/min, with all other potential causes of sinus tachycardia excluded. Patients with IST may experience debilitating palpitations, lightheadedness, chest discomfort, poor exercise tolerance, and other multisystem complaints. It has a complex pathogenesis with many proposed mechanisms, including increased resting sympathetic tone, decreased parasympathetic response, and increased intrinsic sinus node rate. Treatment of IST is variably successful in reducing symptoms. If β-blockers and calcium channel blockers are ineffective, ivabradine, an inhibitor of the hyperpolarizing sodium current, may be better tolerated. For medically refractory symptoms, several methods of endocardial and epicardial ablation to modify the sinus node have been developed. Long-term follow-up is unknown for many of these techniques. We report 2 patients with complex cases of IST and debilitating symptoms despite medical therapy and previous invasive interventions. Both patients were successfully treated with epicardial radiofrequency ablation facilitated by minimally invasive video-assisted thoracoscopic surgery (VATS), with no recurrence of sinus tachycardia after up to 4 years of follow-up.