Background-Rapid activation of a cardiac catheterization laboratory (CCL) has reduced door-to-balloon times in ST-segment elevation myocardial infarction (STEMI), leading to lower mortality. This process is accelerated with prehospital electrocardiography and notification. False activations of the CCL occur at an unknown rate and have been poorly described. Methods and Results-We analyzed 345 consecutive CCL activations for suspected STEMI over 18 months (March 2009 -August 2010