Few Differences Between American and European Guidelines for Syncope

By Will Boggs MD

November 09, 2019

NEW YORK (Reuters Health) - There are few important differences between guidelines for the diagnosis and management of syncope from the American College of Cardiology/American Heart Association/Heart Rhythm Society (ACC/AHA/HRS) and the European Society of Cardiology (ESC), according to a new report.

"Guidelines must be contextually sensitive - what works in the U.S. might not work in the other parts of the world," said Dr. Zachary D. Goldberger of the University of Wisconsin School of Medicine and Public Health, in Madison.

"For U.S., Canadian, and European guidelines, in addition to the considerable differences in health care systems, there are significant differences in how writing committees are formed, how each grades evidence, and what compels the need for updates," he told Reuters Health by email.

As many as 40% of people experience syncope in their lifetime, yet its diagnosis and causal mechanism often remain elusive. Clinical practice guidelines in the U.S. and Europe address the diagnosis, evaluation and treatment of syncope, but there is no uniform set of guidelines.

Dr. Goldberger and colleagues examined major similarities and differences between the 2017 ACC/AHA/HRS and 2018 ESC syncope guidelines, the remaining gaps in knowledge, and their implications for clinical practice and future research in their report, online November 4 in the Journal of the American College of Cardiology.

While both guidelines define syncope similarly, the U.S. guidelines focus on clinical conditions causing syncope, whereas the European guidelines include both syncope and non-syncopal forms of real or apparent transient loss of consciousness.

The European guidelines uniquely address syncope units (dedicated facilities that provide a standard approach in the diagnosis and management of syncope), but both guidelines say that high-risk patients require admission, whereas intermediate-risk patients should be observed in a specialized setting or have an early follow-up and low-risk patients could be discharged with minimal workup.

The authors note key differences in recommendations in patients with conduction disease, reflex syncope, and orthostatic hypotension. The European guidelines offer several recommendations for pacing in syncopal patients who present with bifascicular block without manifest atrioventricular block, whereas the U.S. guidelines lack specific recommendations for these patients.

The guidelines also differ in their recommendations regarding electrophysiological studies and implantable loop recorders. And they offer contrasting advice regarding the treatment of reflex syncope: the European guidelines state that there is no indication for beta-blockers in this setting, while the U.S. guidelines state that beta-blockers might be reasonable in patients 42 years and older.

For orthostatic hypotension, only the European guidelines recommend patient education and reassurance, and only the U.S. guidelines recommend acute water ingestion for neurogenic orthostatic hypotension.

The U.S. guidelines also recommend multiple pharmacotherapies in the treatment of orthostatic hypotension, whereas these medications are mentioned as options with limited evidence and efficacy in the European guidelines.

"The differences between most recommendations simply depend on how each Writing Committee interprets the available evidence," Dr. Goldberger said. "Furthermore, the U.S. and European guidelines often differ in how much attention (and discrete recommendations) they give to specific aspects of syncope management."

"We hope that practitioners from many specialties will gain a better understanding of the basics and nuances in management, and recognize the areas of controversy and gaps in the available evidence," he said.

SOURCE: https://bit.ly/2JXtvAs

J Am Coll Cardiol 2019.