Current issues of ACP Journal Club are published in Annals of Internal Medicine


Diagnosis

The utility of electrophysiologic studies in syncope was dependent upon the prevalence of organic heart disease or ECG abnormality

ACP J Club. 1992 Sept-Oct;117:50. doi:10.7326/ACPJC-1992-117-2-050


Source Citation

Bachinsky WB, Linzer M, Weld L, Estes NA III. Usefulness of clinical characteristics in predicting the outcome of electrophysiologic studies in unexplained syncope. Am J Cardiol. 1992 Apr 15;69:1044-9.


Abstract

Objective

To validate a previously derived model for predicting the outcome of electrophysiologic testing (EPT) in patients with unexplained syncope.

Design

A comparison of 6 clinical predictors (3 for ventricular tachyarrhythmias and 3 for bradyarrhythmias) with EPT results.

Setting

Tertiary care medical center.

Patients

141 consecutive patients (96 men, mean age 59 y) who had EPT for syncope.

Description of test and diagnostic standard

Audit of medical charts gave historical, physical, and investigative findings for organic heart disease. Electrocardiographic abnormalities noted were premature ventricular contractions (PVCs) (≥ 3 PVCs/min, multiform or salvos of PVCs); first-degree heart block (PR interval ≥ 0.2 s); bundle branch block (QRS duration ≥ 0.12 s with left or right bundle branch block pattern or intraventricular delay); and sinus bradycardia (≥ 30 seconds or requiring cardioversion because of hemodynamic compromise; nonsustained, reproducible VT of ≥ 6 beats with severe symptoms or compromise; or ventricular fibrillation induced by ≥ 425 ms; prolonged His-ventricular interval ≥ 90 ms; prolonged corrected sinus node recovery time ≥ 1000 ms; or spontaneous infra-Hisian block or Mobitz II atrioventricular block during incremental atrial pacing.

Main results

EPT identified 18 patients (12%) with ventricular tachyarrhythmic outcomes and 28 (20%) with bradyarrhythmic outcomes. Ventricular tachyarrhythmia was predicted by organic heart disease (odds ratio [OR] 9.1, 95% CI 1.2 to 71.0, P = 0.01) and nonsustained VT on Holter monitoring (OR 3.3, CI 1.2 to 9.3, P = 0.02). Bradyarrhythmia was predicted by sinus bradycardia (OR 6.1, CI 1.3 to 29.1, P = 0.01), first degree heart block (OR 5.6, CI 2.3 to 13.9, P = 0.001), and bundle branch block (OR 3.2, CI 1.4 to 7.5, P = 0.006). Sensitivity of ≥ 1 tachyarrhythmic predictor was 100% and of ≥ 1 bradyarrhythmic predictor was 79%.

Conclusions

Electrophysiologic testing provided useful information in patients with ≥ 1 clinical predictor. For patients without these predictors, electrophysiologic testing had little diagnostic benefit.

Source of funding: National Institutes of Health.

Address for article reprint: Dr. M. Linzer, Box 1042, New England Medical Center, 750 Washington Street, Boston, MA 02111, USA.


Commentary

The study by Bachinsky and colleagues confirms their previous work on identifying clinical predictors of the results of EPT in patients with unexplained syncope. The most important practice recommendation that can be derived from the present study is that EPT for inducible ventricular tachyarrhythmias generally should not be necessary in patients with syncope who have no evidence of organic heart disease and no substantial ventricular ectopy (frequent PVCs or nonsustained VT) on Holter monitoring. An important caveat is that patients with unexplained syncope should probably receive at least 48 hours of Holter monitoring before it is concluded that no substantial ventricular ectopy exists (1). The study also shows that EPT has a moderately high yield of inducible ventricular tachyarrhythmias in patients with syncope and organic heart disease, substantial ventricular ectopy, or both on electrocardiographic monitoring, and a high yield of bradyarrhythmic outcomes in patients with first-degree heart block, bundle branch block, or sinus bradycardia ≤ 50 beats per minute on initial electrocardiography. These findings support existing recommendations to consider EPT in such individuals (2). The precise yield in such patients may vary according to the particular protocol being used for EPT.

Eric B. Bass, MD, MPH
Johns Hopkins HospitalBaltimore, Maryland, USA

Eric B. Bass, MD, MPH
Johns Hopkins Hospital
Baltimore, Maryland, USA


References

1. Bass EB, Curtiss EI, Arena V, et al. The duration of Holter monitoring in patients with syncope: is 24 hours enough? Arch Intern Med. 1990;150:1073-8.

2. Rahimtoola SH, Zipes DP, Akhtar M, et al. Consensus statement of the conference on the state of the art of electrophysiologic testing in the diagnosis and treatment of patients with cardiac arrhythmias. Circulation. 1987;75(Suppl III):III3-11.