ACC/AHA/HRS guideline provides recommendations for diagnosis, prognosis for syncope

The American College of Cardiology, the American Heart Association and Heart Rhythm Society published guidelines for the assessment and treatment of patients with syncope.

Syncope affects up to 41% of the population, and recurrent syncope occurs in 13.5% of patients, according to the guidelines. In addition, women have a higher prevalence of syncope, and older patients face a higher risk for hospitalization and death caused by syncope.

“The purpose of this ACC/AHA/HRS guideline is to provide contemporary, accessible and succinct guidance on the management of adult and pediatric patients with suspected syncope,” Win-Kuang Shen, MD, professor of medicine at Mayo Clinic in Phoenix and chair of the writing committee, and colleagues wrote.

Syncope from heart conditions

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

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

Short-term risk factors for patients with syncope comprise of cerebrovascular disease, structural heart disease, men who are older than 60 years, HF and family history of sudden cardiac death. Diabetes, cancer, ventricular arrhythmias and a high CHADS-2 are some long-term risk factors, according to the document.
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, supraventricular tachycardia, third-degree heart block, acute HF, pacemaker malfunction and bradycardia.

Regular, comprehensive laboratory testing is not beneficial in evaluating patients. Unless the syncope is caused by a cardiac condition, routine cardiac imaging is also not useful.

Use of exercise stress testing to determine the cause of syncope in patients who experience symptoms during exertion was given a class IIa recommendation.

Imaging recommendations

Cardiac monitoring is recommended in patients depending on the nature and frequency of syncope events, supported by class I evidence. Whether external or implantable cardiac monitors should be used is to be determined by the physician.

“Detection with short-term monitoring techniques is often unsuccessful, and as a result, patients may see several different specialists and undergo multiple tests without receiving a conclusive diagnosis,” David Benditt, MD, professor of medicine and co-director of the Cardiac Arrhythmia Center at the University of Minnesota in Minneapolis, said in a press release issued by Medtronic. “When the cause of syncope is unclear, continuous long-term cardiac monitoring has become the standard of care, particularly in early stages of evaluation.”

If there are no focal neurological findings that confirm the need for further evaluation, then routine evaluation should not include carotid artery imaging, according to the guidelines.

Vasovagal syncope is the most common type of reflex syncope, and physicians should educate patients on the diagnosis and prognosis of this condition. Patients with recurring vasovagal syncope and prolonged spontaneous pauses who are 40 years or older may benefit from dual-chamber pacing, the authors wrote in a class IIb recommendation. In pediatric patients, beta-blockers are not beneficial, according to the authors.

Patients with syncope caused by acute dehydration should receive fluid resuscitation by IV or oral bolus, according to Class I recommendations. Class IIa evidence suggests that reducing or eliminating medication that’s causing hypotension may be beneficial.

Guideline-directed management and therapy are class I recommendations for patients with bradycardia, supraventricular tachycardia, ventricular arrhythmia, atrial fibrillation or structural heart conditions.

When other risk factors are not present in patients with reflex-mediated syncope and Brugada ECG pattern, an implantable cardioverter defibrillator is not recommended, according to the authors.

Beta-blocker therapy can serve as a first-line treatment for patients with suspected arrhythmic syncope and long-QT syndrome. If they are intolerant to this therapy or are currently utilizing beta-blockers, an ICD may be practical, per class IIa recommendations.

An electrophysiological study is acceptable for patients with cardiac sarcoidosis and syncope caused by arrhythmia, according to Class IIa recommendations.

Class I recommendations suggest CV assessment for athletes with syncope before they return to competitive sports. Patients should not participate in competitive sports if syncope is caused by catecholaminergic polymorphic ventricular tachycardia, hypertrophic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy or long QT syndrome. – by Darlene Dobkowski

Disclosure : Benditt reports consulting for Medtronic and St. Jude Medical. Shen reports no relevant financial disclosures. Please see the full guideline for the other committee members’ relevant financial disclosures.