Electrotonic currents may flow from endocardial sites with longer action poten- tial durations to the epicardium with shorter action po- tential durations which can result in reexcitation when these sites have recovered from refractoriness. This is believed to be one potential mechanism of VT/VF in and may also be operative dur- ing ischemia. 4. GENERAL EVALUATION OF PATIENTS WITH DOCUMENTED OR SUSPECTED VA 4.1. History and Physical Examination Recommendation for Syncope* Referenced studies that support the recommendation are summarized in Online Data Supplement 1. COR LOE Recommendation I B-NR Patients presenting with syncope for which VA is documented, or thought to be a likely cause, should be hospitalized for evaluation, monitoring, and management.S4.1-1 S4.1-4 *This section covers practices that are well accepted, and a new recommendation was determined to only be warranted for syncope. Synopsis VA can produce a wide spectrum of symptoms, and the severity of symptoms does not necessarily reflect the extent of structural heart disease or the potential risk of SCD. Symptoms of VA include palpitations, either skipped or extra beats or sustained palpitations, short- ness of breath, chest pain, dizziness, near syncope, and Palpitations may correlate with VA but are frequently reported during normal rhythm.S4.1-7 The differential diagnosis of exercise intolerance, chest pain, dyspnea, presyncope, and syncope includes VA but also includes other etiologies. Nonetheless, more dramatic CLINICAL STATEMENTS AND GUIDELINES symptoms, particularly in patients with known or dis- covered structural or electrical heart disease should prompt focused investigation for possible association with VA (Table 6). The elucidation of precipitating factors, such as exertional or emotional stress, concurrent medica- tions or illness, and alleviating factors is important. 