Mechanism of syncope: role of ambulatory blood pressure monitoring and cardiovascular autonomic function assessment
Antonella Groppelli, Vincenzo Russo, Erika Parente, Angelo Comune, Frederik J. de Lange, Giulia Rivasi, Martina Rafanelli, Jean‐Claude Deharo, Jaume Francisco‐Pascual, Roberto Maggi, Artur Fedorowski, Andrea Ungar, Gianfranco Parati, Michele Brignole
Abstract
BACKGROUND AND AIMS: Identifying the haemodynamic mechanism of autonomic syncope is the essential pre-requisite for effective and personalized therapy aimed at preventing recurrences. The present study assessed the diagnostic efficacy of a two-step assessment. METHODS: Multicentre prospective, cross-sectional, observational study. Patients affected by severe autonomic syncope underwent a two-step assessment including 24-h ambulatory blood pressure monitoring and short cardiovascular autonomic function assessment (SCAFA). SCAFA consisted of carotid sinus massage (CSM), performed in patients ≥40 years old, a passive standing test, and a 'fast' head-up tilt test scheduled sequentially during one session on a tilt table. RESULTS: The study population consisted of 333 patients, 102 ≤ 40 years old and 231 > 40 years old. Any positive response was observed in 298 (89%) patients (92 [92%] in younger and 134 [89%] in older), with hypotensive phenotype accounting for 226 (68%), bradycardic phenotype for 21 (6%) and mixed phenotype for 51 (15%) of cases. The mean duration of the SCAFA procedure was 25 (IQR 20-32) min. Ambulatory blood pressure monitoring, CSM, passive standing, and head-up tilt test were positive in 60%, 15%, 3%, and 71% of patients, respectively. More than one test was positive in 51% and 49% of patients ≤40 and >40 years, respectively. Large inter-centre variability of CSM positivity rate, which remained significant after adjustment for demographic and clinical variables, was observed (P = .003). CONCLUSIONS: The standardized 2STEPS protocol offers an easy-to-perform and time-saving diagnostic work-up allowing identification of the haemodynamic mechanism of loss of consciousness in most patients with autonomic syncope. This protocol provides the necessary background for a personalized mechanism-specific therapy.