Minimally Invasive Surgical Ablation For Inappropriate Sinus Tachycardia
Robert M. MacGregor, Ali J. Khiabani, Joshua L. Manghelli, Daniel I. Carter, Richard B. Schuessler, Spencer J. Melby, Ralph J. Damiano, Jr..
Washington University in St. Louis, St. Louis, MO, USA.
Objective:Inappropriate sinus tachycardia (IST) is a rare clinical condition characterized by an elevated resting heart rate and an exaggerated rate response to exercise or stress. Patients unresponsive to medical therapy often undergo catheter ablation of the SA node, however the long-term results have been poor. The purpose of this study was to examine the outcomes of minimally-invasive surgical treatment for IST at our institution.
Methods:Between 2004 and 2018, seven patients underwent sinoatrial (SA) node isolation via minimally-invasive right thoracotomy for treatment of refractory IST. Bipolar radiofrequency and cryotherapy were used for the ablation in all patients. Preoperative patient demographics, previous treatments for IST, duration of symptoms, and postoperative outcomes were collected. The primary end-points were freedom from tachyarrhythmia recurrence as well as symptomatology at the last available follow-up. Postoperative heart rhythm was obtained by 12-lead electrocardiogram (ECG), or prolonged monitoring by Holter monitor or pacemaker interrogation.
Results:The median follow-up time was 8.1 years (IQR[0.4,13.9]). Average age was 32.7±8.0 years. Prior to surgical ablation, the mean duration of symptoms from IST was 3±2.1 years. All patients had previously failed pharmacologic therapy, and five of seven patients (71.4%) had failed at least one catheter ablation (Median[IQR] of 1 [0,1]; Range 0-4) prior to surgery. Intraoperatively, the strategy was to isolate the SA node region and modify the neural input using cryoablation. Ablation was performed off-pump with thoracoscopic guidance and without rib spreading. Ablation was continued until there was p-wave inversion and a blunted chronotropic response to isoproterenol. All patients survived surgery and there were no major complications. Sinus tachycardia was eliminated in all seven patients in the immediate postoperative period. One patient (16.7%) required post-operative pacemaker placement due to symptomatic sinus bradycardia. Only two patients (28.6%) required post-operative beta-blocker usage. There were no documented recurrent episodes of IST. At last follow-up, all seven patients were in normal sinus rhythm and asymptomatic.
Conclusions:Minimally-invasive surgical isolation of the SA node is an effective treatment for IST refractory to pharmacologic therapy and catheter ablation. The minimally-invasive approach offers a less morbid alternative to sternotomy, and may be more attractive to patients and referring cardiologists.
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