Electrophysiologic testing in patients with unexplained syncope: Clinical and noninvasive predictors of outcome

Abstract

To assess whether the level of risk of having significant electrophysiologic abnormalities can be determined, 29 clinical variables were analyzed in 104 patients with unexplained syncope who underwent electrophysiologic testing. A positive electrophysiologic study was defined as: a sinus node recovery time greater than or equal to 3 seconds; HV interval greater than or equal to 100 ms; infranodal block during atrial pacing; unimorphic ventricular tachycardia; and supraventricular tachycardia associated with hypotension. Thirty-one patients had a positive study, with inducible ventricular tachycardia being the most common finding (71% of positive studies). A left ventricular ejection fraction less than or equal to 0.40 was the most powerful predictor of a positive electrophysiologic study (p less than 0.00001), followed by the presence of bundle branch block (p less than 0.00003), coronary artery disease (p less than 0.0003), remote myocardial infarction (p less than 0.00006), use of type 1 antiarrhythmic drugs (p less than 0.00003), injury related to loss of consciousness (p less than 0.01) and male sex (p less than 0.01). A negative electrophysiologic study was associated with an ejection fraction greater than 0.40 (p less than 0.00001), the absence of structural heart disease (p less than 0.00001), a normal electrocardiogram (ECG) (p less than 0.0001) and normal ambulatory ECG monitoring (p less than 0.0001). The probability of a negative study increased as the number and duration of syncopal episodes increased.(ABSTRACT TRUNCATED AT 250 WORDS)

2017 ACC/AHA/HRS Guideline for the Evaluation and Management of Patients With Syncope: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society

“…In this setting, a structured ED protocol can be effective as an alternative to inpatient admission. [107][108][109][110] Decision support algorithms may reduce health service use in the evaluation of syncope (Figures 1 and 2), 105,[111][112][113] although there are currently insufficient data to advocate the use of specific decision support algorithms for making disposition decisions.…”

Syncope in Dilated Cardiomyopathy Is a Predictor of Sudden Cardiac Death

“…In 1990 Kapoor [9] reported a 33% sudden death incidence at 5 years in patients with a cardiac syncope as compared with 5% in those with a noncardiac syncope. If patients with unex plained syncope are tested with electrophysiological stud ies, reduced left-ventricular ejection fraction (less than 40%) is reported to be the most powerful predictor of a positive electrophysiological study [10], On the other hand, a nondiagnostic electrophysiological test is not helpful for identifying those who arc at high risk of sudden death [11], Therefore, we decided not to perform an elec trophysiological test in our patients.…”

Syncope in Patients with Organic Heart Disease

“…[76][77][78] If sustained monomorphic ventricular tachycardia is induced with an accepted protocol in a patient with organic heart disease, the long-term risk is poor, 79 but these risks may be predicted by other means including LVEF or NYHA functional class. 80 The predictive accuracy of an electrophysiology test is greatest in patients with coronary artery disease and impaired LVEF. The electrophysiology test is not particularly good at deciphering the risk of bradyarrhythmias.…”