Utility of Head up Tilt Table Testing to Demonstrate Selective Denervation of the Sinus Node after Cardioneuroablation.

A 65-year-old female who underwent cardioneuroablation for recurrent vasovagal syncope presented for 6 month follow-up visit. She had no further syncope after the procedure. A follow up tilt table testing (TT) demonstrated sinus tachycardia and variable degrees of atrioventricular block (AVB) after sublingual glyceryl trinitrate. She had no syncope during the test. As per existing knowledge, the occurrence of AVB during vasovagal reaction induced by TT should be preceded by sinus rhythm slowing.  In this patient, sinus tachycardia during TT demonstrates highly specific denervation of ganglion cells which send postganglionic fibers directly to the sinus node without obvious influence on the atrioventricular node.