Cardiac Electrophysiology in Stroke Investigation: Holter, Event Monitor, and Long-Term Monitoring

Identifying the etiology of ischemic stroke is critical to providing optimum therapy and preventing future events. Unfortunately, it is not always a simple task to establish the source, which all too often results in the diagnosis of “cryptogenic” stroke. Since cardiac sources of emboli are a well-known and significant cause of ischemic stroke, and may require different patient management, substantial effort has been made into the investigation for cardiac sources. The most important cardiac etiology for embolus is atrial fibrillation (AF), which may account for approximately 15–20% of cases of ischemic stroke. Atrial flutter, although less common, also can result in stroke, and its detection is also important.

However, not all patients with AF as the cause of stroke are known to have the diagnosis before the embolic event, nor do they necessarily present with AF at the time of the stroke. Many patients with AF have no cardiac symptoms, and the diagnosis is made only incidentally or after varying levels of search. Paroxysmal and persistent AF are considered to have a similar risk of stroke; therefore a presentation in sinus rhythm does not exclude AF as the cause of stroke. In fact, it is often in the period after the spontaneous conversion of fibrillation that embolization occurs.