Field ECGs Do Not Delay Hospital Arrival for Patients with Chest Pain

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Obtaining an electrocardiogram (ECG) in patients with chest pain on the way to the hospital causes only minimal delays, and the practice can even reduce delays for those experiencing ST-segment myocardial infarction (STEMI). The findings, from a citywide observational study, were published online July 25, 2012, ahead of print in the Journal of the American College of Cardiology.

Ehtisham Mahmud, MD, of the University of California, San Diego (San Diego, CA), and colleagues looked at 21,742 patients evaluated for chest pain from January 2003 to April 2008. Results were compared in the periods before and after the end of 2005, when emergency medical services (EMS) personnel began routine administration of prehospital ECGs during ambulance transport.

Median values for scene time (spanning the arrival of paramedics until an ECG was performed) and transport time (from the departure of the ambulance from the scene to its arrival at the emergency department) were only slightly higher when a prehospital ECG was obtained (table 1).

Table 1. Effect of Prehospital ECG Implementationa




P Value

Scene Time

19 min, 10 sec

19 min, 28 sec


Transport Time

13 min, 16 sec

13 min, 28 sec


a Median values.

After 2005, patients with STEMI saw even shorter median delays than did patients with other explanations for their chest pain. The overall scene-to-hospital time was nearly 3 minutes less for STEMI (table 2).

Table 2. Effect of Diagnosis on Timinga



Chest Pain Alone

P Value

Scene Time

17 min, 51 sec

19 min, 31 sec

< 0.001

Transport Time

12 min, 34 sec

13 min, 31 sec


Scene-to-Hospital Time

30 min, 45 sec

33 min, 29 sec

< 0.001

a Median values.

The delays brought on by field ECGs are “clinically insignificant,” the authors note. Importantly, they say, the findings “demonstrate that EMS personnel have improved their workflow to [ensure] that [prehospital] ECG does not adversely prolong both scene and transport times for patients who are evaluated for chest pain of cardiac origin. In fact, when the diagnosis of STEMI is made in the field, the EMS arrival-to-hospital time is lower than for other chest pain patients, thereby potentially reducing total ischemic time.”

Showing Quality Improvement Can Work

In an editorial accompanying the paper, Umesh N. Khot, MD, of the Cleveland Clinic (Cleveland, OH), raises the issue that quality improvement efforts in health care carry a risk of unintended consequences. Before the current study, he says, “it was unclear if widespread integration of prehospital ECG would lead to increased ambulance scene time, negating the benefits of reduced door-to-balloon times and ultimately causing an increase in overall time to treatment.”

Because fewer than 5% of patients with chest pain in fact have ST-elevation on ECG, Dr. Khot adds, “a very large population of patients has to be exposed to this prehospital intervention, although only a very small number will actually benefit.”

The study demonstrates, however, that the overall increase “was extremely modest and almost certainly not clinically significant,” he concludes, noting, “This work conclusively alleviates the concerns of scene delays,” and stands as an example of how quality improvement efforts can be tested and documented.

Many Contributors to Success

Dr. Mahmud told TCTMD in a telephone interview that several components are involved in transporting STEMI patients to the hospital quickly. In addition to adopting the practice of performing field ECGs, San Diego county also has a “paramedic education [program] about STEMI patients [that explains] the whole rationale of why door-to-balloon time is so important.” Starting in 2004, he said, “we got all the cath lab directors, hospital administrators, and county EMS leadership together to come up with a system in San Diego county for prehospital activation” of the cath lab that was fully in place by early 2007. Specifically, patients diagnosed with STEMI are transported by EMS directly to the closest STEMI receiving center.

“It requires so many different pieces,” Dr. Mahmud said, noting that funding is a crucial element to building such a program.

Among all the players involved, interventional cardiologists “are front and center,” he commented. “If the interventionalists are not on board, it’s very hard to do this. Part of it is that that there are still about 25 to 30 percent false [STEMI] activations. . . . We’re now coming up with streamlined ways to make the diagnoses.”

In a telephone interview with TCTMD, Ajay J. Kirtane, MD, SM, of Columbia University Medical Center (New York, NY), said that ECGs can be readily performed in the ambulance with modern technology but the “really critical thing is the ability to transmit [the test results and activate the cath lab prior to arrival]. It’s not just performing the ECG but also what you do with it.”

Eliminating the ER

Thomas D. Stuckey, MD, of LeBauer Cardiovascular Research Foundation (Greensboro, NC), agreed, describing his own experience in reading ECG results via smartphone. A major asset of “field identification [of STEMI] is that you can eliminate the emergency room,” where many of the delays occur, he commented to TCTMD in a telephone interview.

Dr. Kirtane added that EMS personnel “out in the field are on the front lines, and they [are passionate] about doing things to help their patients while they’re out there. When they see something like ST elevation that they can react to, that empowers [them]. It’s one of the few circumstances where what they do time-wise really can impact whether a patient lives or dies.”

Barriers to developing a program like San Diego’s include infrastructure and technology issues as well as political hurdles, Dr. Kirtane said, “but it’s clear that EMS personnel can be trained” to perform in-ambulance ECGs and that such training can improve patient care.

“What a door-to-balloon time program represents,” Dr. Stuckey concluded, “is a hospital’s and community’s ability to integrate care across various lines, from emergency medical services, to the emergency room, to the cath lab, to the cardiologist. It’s a whole spectrum of care that needs to be coordinated.”

In particular, he stressed, interventionalists must “be thought leaders and drivers of the process to improvement.”


1. Patel M, Dunford JV, Aguilar S, et al. Pre-hospital electrocardiography by emergency medical personnel: Effects on scene and transport times for chest pain and ST-segment elevation myocardial infarction patients. J Am Coll Cardiol. 2012;Epub ahead of print.

2. Khot UN. Exploring the risk of unintended consequences of quality improvement efforts. J Am Coll Cardiol. 2012;Epub ahead of print.



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  • Drs. Mahmud, Khot, Kirtane, and Stuckey report no relevant conflicts of interest.