Correlation of noninvasive electrocardiography with invasive electrophysiology in syncope of unknown origin: implications from a large syncope database.
BACKGROUND
The evaluation of syncope can be expensive, unfocussed, and unrevealing yet, failure to diagnose an arrhythmic cause of syncope is a major problem. We investigate the utility of noninvasive electrocardiographic evaluation (12-lead ECG and 24-hour ambulatory electrocardiographic recordings) to predict electrophysiology study results in patients with undiagnosed syncope.


METHODS
We evaluated 421 patients with undiagnosed syncope who had an electrocardiogram (ECG), an electrophysiology study, and 24-hour ambulatory monitoring. Noninvasive testing was used to predict electrophysiology testing outcomes. Multivariable logistic regression analysis adjusting for age, sex, presence of heart disease, and left ventricular ejection fraction (LVEF) was used to assess independent predictors for sinus node disease, atrioventricular node disease, and induction of ventricular tachyarrhythmias.


RESULTS
Patients were divided into four groups: group 1, abnormal ECG and ambulatory monitor; group 2, abnormal ECG only; group 3, abnormal ambulatory monitor; and group 4, normal ECG and ambulatory monitor. The likelihood of finding at least one abnormality during electrophysiologic testing among the four groups was highest in group 1 (82.2%) and lower in groups 2 and 3 (68.1% and 33.7%, respectively). In group 4, any electrophysiology study abnormality was low (9.1%). Odds ratios (OR) were 35.9 (P < 0.001), 17.8 (P < 0.001), and 3.5 (P = 0.064) for abnormal findings on electrophysiology study, respectively (first three groups vs the fourth one). ECG and ambulatory monitor results predicted results of electrophysiology testing.


CONCLUSIONS
Abnormal ECG findings on noninvasive testing are well correlated with potential brady- or/and tachyarrhythmic causes of syncope, in electrophysiology study of patients with undiagnosed syncope.
Gatzoulis
Konstantinos A
KA
EP Lab, Hippokration Hospital, Athens, Greece. kgatzoul@med.uoa.gr
Karystinos
George
G
Gialernios
Theodoros
T
Sotiropoulos
Helias
H
Synetos
Andreas
A
Dilaveris
Polychronis
P
Sideris
Skevos
S
Kalikazaros
Ioannis
I
Olshansky
Brian
B
Stefanadis
Christodoulos I
CI
D000704:Analysis of Variance; D001145:Arrhythmias, Cardiac / Q000150:complications* / Q000175:diagnosis*; D016208:Databases, Factual / Q000706:statistics & numerical data*; D004562:Electrocardiography / Q000379:methods*; D015716:Electrocardiography, Ambulatory / Q000379:methods; D022062:Electrophysiologic Techniques, Cardiac / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D011237:Predictive Value of Tests; D013575:Syncope / Q000209:etiology*