2017 ACC/AHA/HRS Guideline for the Evaluation and Management of Patients With Syncope

Year Released: 2017

Societies: American College of Cardiology (ACC), American Heart Association (AHA), Heart Rhythm Society (HRS)

Collaborations: American College of Emergency Physicians (ACEP), Society for Academic Emergency Medicine (SAEM)


The ACC, AHA and HRS made evidence-based recommendations on how to better assess and treat patients with syncope.

Syncope — a temporary loss of consciousness usually related to insufficient blood flow to the brain — affects up to 41% of the population, and recurrent syncope occurs in 13.5% of patients, according to the guidelines. Additionally, women have a higher prevalence of syncope, and older patients face a higher risk for hospitalization and death caused by syncope.

Some characteristics associated with cardiac-related syncope include age older than 60 years, male sex, previous arrhythmias, presence of ischemic heart disease (IHD) and presence of known congenital heart disease, according to the panel.

Short-term risk factors for patients with syncope include cerebrovascular disease, structural heart disease, men who are older than 60 years, heart failure (HF) and family history of sudden cardiac death (SCD). Diabetes, cancer, ventricular arrhythmias (VAs) and a high CHADS2 score are some long-term risk factors, according to the document.

Recommendations for testing

The panel placed recommendations into various classes to help identify the strength of each recommendation. Anything labeled as class I was considered strong, recommended and should be performed or administered. Anything labeled class III had no benefit or the risk outweighs the benefit.

Class I recommendations include performing a detailed history and physical exam on patients with syncope, including a resting 12-lead electrocardiogram (ECG). An evaluation for the cause of syncope and short- and long-term morbidity and mortality risk is also recommended.

After initial evaluation, a class I recommendation suggests hospital evaluation and treatment for those with syncope that may have been caused by a serious medical condition, such as ventricular tachycardia (VT), supraventricular tachycardia (SVT), third-degree heart block, pacemaker malfunction and acute HF.


Class I evidence supports cardiac monitoring in patients, depending on the nature and frequency of syncope events. Whether external or implantable cardiac monitors (ICMs) should be used is to be determined by the physician.

The panel recommends that if there are no focal neurological findings that confirm the need for further evaluation, then routine evaluation should not include carotid artery imaging.

Testing athletes

Class I recommendations suggest cardiovascular (CV) assessment for athletes with syncope before they return to competitive sports. The panel recommends that patients should not participate in competitive sports if syncope is caused by catecholaminergic polymorphic VT (CPVT), hypertrophic cardiomyopathy (HCM), arrhythmogenic right ventricular cardiomyopathy (ARVC) or long QT syndrome (LQTS).

Future developments

The panel wrote that prospectively designed multicenter or national registries are needed to gather clinical information from patients with reflex syncope to better understand other associated conditions, plausible mechanisms, effectiveness of therapeutic interventions and natural history of these uncommon conditions.

Additionally, randomized controlled trials are needed to continue the identification of effective treatment approaches to patients with recurrent reflex syncope.

Read more:

Shen WK, et al. J Am Coll Cardiol. 2017;doi:10.1016/j.jacc.2017.03.003.

Cardiology Today coverage: https://www.healio.com/cardiology/arrhythmia-disorders/news/online/%7bf22f377d-0aa2-4c31-958e-eec05bd1e0bd%7d/accahahrs-guideline-provides-recommendations-for-diagnosis-prognosis-for-syncope