12-lead ECG and Exercise Testing Recommendations for 12-lead ECG and Exercise Testing Referenced studies that support the recommendations are summarized in Online Data Supplement 2. COR LOE Recommendations I B-NR In patients with sustained, hemodynamically stable, wide complex tachycardia, a 12- lead ECG during tachycardia should be I B-NR In patients with VA symptoms associated with exertion, suspected ischemic heart disease, or catecholaminergic polymorphic ventricular tachycardia, exercise treadmill testing is useful to assess for exercise-induced I B-NR In patients with suspected or documented VA, a 12-lead ECG should be obtained in sinus rhythm to look for evidence of heart Recommendation-Specific Supportive Text 1. A 12-lead ECG during tachycardia is the first diagnostic test that should be done in any patient found to be in a stable wide QRS complex tachy- cardia on a monitor. VT is the diagnosis in most adults with wide complex tachycardia and under- lying structural heart disease.S4.2.1-3 Criteria that support a diagnosis of VT include AV dissocia- tion, a QRS complex >0.14 s, monophasic R wave in aVR, specific QRS morphologies (eg, positively or negatively concordant QRS complexes in the precordial leads), the absence of an RS complex in all precordial leads and an RS interval >100 ms in at least 1 precordial lead.S4.2.1-2 Exceptions occur, particularly in patients with advanced heart disease and with the use of certain anti- For patients with preexisting bundle branch block, comparison of the QRS morphology during sinus rhythm with that during wide complex tachycardia is often relevant. 2. For exertion-related arrhythmic symptoms, exer- cise in a monitored setting may reproduce the symptoms and/or the related arrhythmia, allow- ing for diagnosis. Exercise testing is particularly important when catecholaminergic polymorphic ventricular tachycardia is a possibility. 