AliveCor (www.alivecor.com) has developed several electrocardiogram (ECG) devices that interface with iOS and Android smartphones and tablets via various Kardia apps. The current Kardia family of devices can measure single lead and six limb-lead ECGs, depending on the device. KardiaMobile, KardiaMobile 6L, and KardiaMobile Card have FDA clearance for ECG rhythm recording. A modified single-lead Kardia smartphone 12-lead ECG was previously validated in the multicenter ST LEUIS study for the diagnosis of ST-Segment Elevation Myocardial Infarction (STEMI) and Non-ST-Elevation Myocardial Infarction (NSTEMI). Recently, AliveCor developed a new device: AliveCor (AC) 12-lead (12L) ECG System to record simultaneously 4 leads of ECG and then generate complete 12-lead ECGs. A previous protocol at the University of Oklahoma involved 200 subjects with early prototypes of the AC 12L device with the specific aim to validate that it accurately generated 12-lead ECGs as compared to simultaneously acquired FDA-cleared 12-lead ECGs. The prototype version of the AliveCor 12L ECG System simultaneously measured four channels of ECG (leads I, II, V2, V4), calculated the remaining limb leads as is standard for 12-lead ECGs (Leads III, aVR, aVL, aVF) and synthesized the remaining 4 precordial ECG leads (V1, V3, V5, V6). This protocol will serve to validate the production version of the system against standard 12-Lead ECGs for the diagnosis of STEMI and NSTEMI in patients admitted to the Emergency Department or directly to the Cardiac Cath Lab for the evaluation of chest pain. It is anticipated that the waveforms for each of the 12 leads from the AC 12L ECG System will be highly correlated with the corresponding leads from the comparator commercially available 12-lead ECG devices used at participating sites. The purpose of this study is to clinically validate that the four-channel AC 12L ECG device can enable the diagnosis of STEMI and NSTEMI in a non-inferior manner to existing 12-lead ECG devices.