Although randomized studies are unavailable, coronary angiography has an important role in establishing or excluding the presence of sig- nificant obstructive ischemic heart disease in patients with SCA or those with life-threatening Recurrent polymorphic VT or VF can be due to ongoing myocardial ischemia that resolves with coronary revascularization. Presence of ST-elevation on preresuscitation or early postresuscitation ECG suggests ischemia and potential ACS warranting urgent angiography and ST-elevation can also result from coronary spasm or DC shocks. The absence of ST-elevation after cardiac arrest does not exclude obstructive or thrombotic coronary lesions. A cor- onary angiogram may not be warranted if a non- ischemic cause of SCA is established. Coronary and CT angiography also have an important role excluding the presence of anomalous origin of the coronary arteries that may cause SCD. 4.3.2. Electrophysiological Study for VA Recommendations for Electrophysiological Study References that support the recommendations are summarized in Online Data Supplements 8 and 9. 