Unexplained Syncope: The Importance of the Electrophysiology Study

Abstract

Syncope of cardiac origin may be associated with an increased risk of sudden cardiac death if not treated in a timely and appropriate manner. The diagnostic approach of syncope imposes a significant economic burden on society. The investigation and elucidation of the pathogenetic mechanism of syncope are of great clinical importance, as both prognosis and appropriate therapeutic approaches depend on these factors. The responsible mechanism of presyncope or syncope can only be revealed through the patient history, baseline clinical examination and electrocardiogram. The percentage of patients who are diagnosed with these tests alone exceeds 50%. In patients with a history of organic or acquired heart disease or/and the presence of abnormal findings on the electrocardiogram, a further diagnostic electrophysiology inclusive approach should be followed to exclude life threatening arrhythmiological mechanism. However, if the patient does not suffer from underlying heart disease and does not show abnormal electrocardiographic findings in the electrocardiogram, then the probability in the electrophysiology study to find a responsible cause is small but not absent. The role of a two-step electrophysiology study inclusive risk stratification approach for the effective management of the former is thoroughly discussed in this review.

Management of Patients With Unexplained Syncope: Derivation and Validation of a Simplified 2‐Step Diagnostic Approach

“…Two independent cohorts were used from the first University Department of Cardiology at the “Hippokration” Hospital: the derivation cohort that has been previously described recruited 665 patients on the basis of electronic health records data from outpatient and inpatient registries to develop our diagnostic approach from 1995 to 2017. 12 , 13 , 14 The validation cohort was based on 160 prospective real‐world screened patients, presenting with unexplained syncope attacks admitted to our hospital from 2019 to 2022. In addition, the methodology of the PRESERVE‐EF (Risk Stratification in Patients With Preserved Ejection Fraction) study (described below in the section Patients With Unexplained Syncope and Ischemic Cardiomyopathy With Preserved Ejection Fraction) was applied for patients after STEMI with left ventricular ejection fraction >35% presenting with unexplained syncope.…”

“…The methodology of obtaining noninvasive electrocardiographic features and invasive EPS results has been previously published and has been consistently performed since the beginning of the study (as described below) 12 , 13 , 14 , 15 , 18 , 19 , 20 :…”

Recent Advances and Future Directions in Syncope Management: A Comprehensive Narrative Review

“…An electrophysiological study (EPS) is recommended to identify arrhythmic syncope in patients with a history of organic or acquired heart disease or/and the presence of abnormal findings on the ECG [83].…”

Tachyarrhythmias in congenital heart disease

“…In patients presenting with syncope, the ILR and electrophysiological study play an important role. In patients with a high clinical risk profile, especially those with myocardial scar or conduction disturbances, EPS not only yields a substantial number of diagnoses but also identifies patients at lower risk of arrhythmic syncope ( 21 – 29 ). However, its negative predictive value has been considered to be suboptimal (around 70%) ( 24 , 30 ), and in such cases, further work up might be needed.…”