Electrophysiology Testing: Appropriate Indications in TLOC/Collapse

Abstract

Arrhythmias including bradycardia, tachyarrhythmias, and conduction issues may result in syncope, but often there is difficulty correlating an arrhythmia to clinical symptoms. Non-invasive monitoring including Holter monitoring, event recording, patch recorders, mobile cardiac outpatient telemetry, and the so-called smart watch applications may be insufficient to document a correlation due to a number of reasons. The episodes of syncope may be infrequent or could even be an isolated event occurring during a high risk situation, such as driving or operating heavy machinery. Other patients may have sudden incapacitation limiting their ability to trigger recording of any arrhythmia. Some patients are averse to having prolonged exposure to adhesives used to affix these monitoring leads to the chest. While implantable cardiac monitor has become significantly smaller over the past few years, it is still invasive and does not provide any therapy in case of an arrhythmia.

When the suspicion for arrhythmia causing syncope is high, EPS can be useful in these selected patients. Diagnostic results during EPS are common when patients have a history of cardiac disease or structural heart disease. For patients with bradyarrhythmias, the EPS can potentially determine the etiology such as sinus node or AV node dysfunction, and then guide subsequent therapy including pacemaker implantation. When a supraventricular tachyarrhythmia occurs with EPS, many of these can be treated with ablation leading to long-lasting freedom from these arrhythmias. In patients with syncope and ischemic heart disease, an EPS with inducible ventricular tachyarrhythmias carries prognostic information, which may guide future therapy including antiarrhythmic medication, ablation, and implantable cardioverter-defibrillator implantation.