Reducing Time to First Cardiac Marker Results by Integrating Prehospital and ED Protocols

Abstract

Coronary heart disease (CHD) is the leading cause of mortality among men and women in the United States. It is estimated that about every 26 seconds an American will experience a coronary event, leading to at least one death every minute. Approximately 325,000 CHDrelated deaths occur in the emergency department or in outof-hospital settings each year, and a significant number of these deaths are attributed to acute myocardial infarction (AMI). 1 One of the most difficult and critical differential diagnoses made in the emergency room is for AMI. Patients present with a variety of confounding symptoms, not always the crushing and radiating pain that is widely seen as the hallmark of a cardiac event. In 2004, 865,000 new and recurrent AMIs were diagnosed in the United States, and of these patients, more than 157,000 did not survive. 2 With the sudden death rate among people who have had an AMI at 4 to 6 times that of the general population, timely identification and intervention is critical in the optimal care of patients with either type of AMI: ST elevation MI (STEMI) or non-ST elevation MI (NSTEMI). In the case of STEMI, a condition where a coronary artery is completely blocked, fast treatment is required because blood flow not restored within 20 minutes could result in permanent damage to the heart muscle and increased likelihood of death. De Luca et al 3 have shown a direct correlation between 1-year mortality and the length of time from symptom onset to balloon inflation. STEMI diagnosis is generally straightforward as a classic ECG pattern swiftly identifies the AMI. With regard to NSTEMIs, early identification and treatment are necessary to prevent further damage caused by ischemia. By definition, the ECGs of patients with NSTEMI are nondiagnostic; therefore, an alternative way to identify these patients early is critical, allowing clinicians to administer the most appropriate treatment as rapidly as possible. The use of a rapid cardiac marker panel that includes an early and a specific marker, such as myoglobin and troponin, is an effective means to support rapid diagnosis of NSTEMIs. 4