AUTHOR=Yasa Ekrem , Ricci Fabrizio , Holm Hannes , Persson Torbjörn , Melander Olle , Sutton Richard , Fedorowski Artur , Hamrefors Viktor 

TITLE=Cardiovascular Autonomic Dysfunction Is the Most Common Cause of Syncope in Paced Patients

JOURNAL=Frontiers in Cardiovascular Medicine

VOLUME=6

YEAR=2019

URL=https://www.frontiersin.org/journals/cardiovascular-medicine/articles/10.3389/fcvm.2019.00154

DOI=10.3389/fcvm.2019.00154

ISSN=2297-055X

ABSTRACT=<p><bold>Introduction:</bold> Syncope and orthostatic intolerance in paced patients constitute a common clinical dilemma. We, thus, aimed to determine the etiology of syncope and/or symptoms of orthostatic intolerance in paced patients.</p><p><bold>Methods:</bold> Among 1,705 patients with unexplained syncope and/or orthostatic intolerance that were investigated by cardiovascular autonomic tests, including Valsalva <italic>maneuver</italic>, active standing, carotid sinus massage, and tilt-testing, 39 patients (2.3%; age 65.6 years; 39% women) had a cardiac implantable electronic device (CIED). We explored past medical history, diagnoses found during cardiovascular autonomic tests, and the further clinical workup, in case of negative initial evaluation.</p><p><bold>Results:</bold> An etiology was identified during cardiovascular autonomic tests in 36 of the 39 patients. Orthostatic hypotension (<italic>n</italic> = 16; 41%) and vasovagal syncope (<italic>n</italic> = 12; 31%) were the most common diagnoses. There were no cases of pacemaker dysfunction. The original pacing indications followed guidelines (sick-sinus-syndrome in 16, atrioventricular block in 16, atrial fibrillation with bradycardia in five). Twenty-two of the 39 patients (56%) had experienced syncope prior to the original <italic>CIED</italic> implantation. Orthostatic hypotension was diagnosed in seven (32%) and vasovagal syncope in nine (41%) of these patients. Of the 17 patients that had not experienced syncope prior to the original CIED implantation, nine patients (53%) were diagnosed with orthostatic hypotension and vasovagal syncope was diagnosed in three (18%). Of the 39 patients, two had implantable cardioverter-defibrillators to treat malignant ventricular arrhythmias diagnosed after syncopal episodes.</p><p><bold>Conclusion:</bold> Cardiovascular autonomic tests reveal the etiology of syncope and/or orthostatic intolerance in the majority of paced patients. The most common diagnosis was orthostatic hypotension (40%) followed by vasovagal syncope (30%), whereas there were no cases of pacemaker dysfunction. Our results emphasize the importance of a complete diagnostic work-up, including cardiovascular autonomic tests, in paced patients that present with syncope and/or orthostatic intolerance.</p>