Prehospital ECGs and STEMI Receiving Centers

An important paper has been published that deserves to be read in its entirety.

Rokos IC, French WF, Koenig WJ, et al. Integration of pre-hospital electrocardiograms and ST-elevation myocardial infarction receiving center (SRC) networks: Impact on door-to-balloon times across 10 independent regions. J Am Coll Cardiol Cardiovasc Intervent 2009; 2:339–346

Here are some highlights:

"There were 2,712 patients diagnosed with STEMI by PH-ECG. In the 2,053 (76%) who underwent PPCI, pooled data from all 10 independently managed regions demonstrated an 86% rate of D2B ≤90 min. When assessed by individual region, the rate of D2B ≤90 min ranged from 77% to 97%.

Further analyses of the entire 2,053 patient cohort undergoing PPCI demonstrated a 50% rate of D2B ≤60 min, 25% rate of D2B ≤45 min, and an 8% rate of D2B ≤30 min. There was a 68% rate of E2B ≤90 min in this study. The E2B times could be determined in 762 of 2,053 (37%) patients, because only 5 of 10 regions had records that included the time of the first PH-ECG consistent with STEMI."

I am particularly impressed that half of all patients in the study had D2B times ≤ 60 minutes.

Based upon this successful SRC network experience across 10 independent regions, we propose 3 areas of focus as STEMI regionalization expands across the nation. In reporting time-zero for E2B, our analysis used the PH-ECG time as previously defined, whereas the most recent STEMI guidelines use time of EMS arrival on scene. In reality, the true patient-centered time-zero for STEMI systems is time of 9-1-1 call, and hence this time-point represents the ideal starting point of E2B that should be tracked in future analyses. Time of EMS alarm/dispatch (usually occurring within a few minutes of 9-1-1 call initiation) is generally documented by paramedics and represents a reasonable surrogate for this ideal time-zero.

I wholeheartedly agree. There's also something else that needs to be said. What about those STEMI patients for whom EMS neglects to perform a PH12ECG? First-medical-contact is first-medical-contact, whether an ECG is performed or not. If the hospital neglects to perform a 12 lead ECG until 30 minutes after the patient's arrival in the ED, they still have to report their D2B time (not their ECG-to-balloon time). EMS should be held to the same standard.

"Second, any STEMI registry supporting the AHA-ML initiative and tracking overall resource use needs to broaden its entry criteria as previously proposed. Subsequent events for all patients with a PH-ECG interpreted as presumed STEMI need to be prospectively tracked. This approach, as performed in our 10-region study, provides the true denominator of STEMI system activations.

Absolutely. Every patient counts.

"Third, minimizing false-positive CCL activations is of potential interest for both interventional cardiologists and hospital administrators. The automated computer algorithm was the most frequently used in this study of the 3 existing PH-ECG interpretation strategies, because it could be rapidly implemented across large EMS systems and was considered reasonably accurate. However, given the real-world occurrence of incorrect computer algorithm analyses for various technical reasons, some regions have taken a Bayesian approach and set strict criteria for paramedic diagnosis of STEMI and CCL activation. For other regions, PH-ECG activation of the CCL has evolved into a 2-step process in which the on-duty ED physician served as the filter after radio communication with EMS. The ED physician then decided in real-time (24/7) which pre-hospital "STEMI Alert" merits conversion to an in-hospital "Code STEMI" involving CCL activation before patient arrival and which patients need further assessment in the ED to determine whether CCL activation is warranted. Simultaneous use of all 3 PH-ECG interpretation strategies might be the best approach in the future, because evidence suggests that the accuracy of in-hospital Code STEMI activation can be further optimized by PH-ECG wireless transmission and physician interpretation. Further study is warranted."

This is why paramedics need to be able to interpet a 12 lead ECG at a very high level. I, for one, am tired of hearing excuses. The National Standard Curriculum for Paramedic states that a paramedic should be able to:

• Recognize the changes on the ECG that may reflect evidence of myocardial ischemia and injury.
• Recognize the limitations of the ECG in reflecting evidence of myocardial ischemia and injury.

In spite of this, paramedics are not receiving adquate training in 12 lead ECG interpretation in school. It's time for the National Standard Curriculum to specify exactly what kind of training is required, and those specifications ought to include axis determination, conduction abnormalities, differential diagnosis of tachycardias, STEMI recognition, the STE-mimics, and identifying AMI in the presence of baseline abnormalities.

How can anyone argue that paramedics don't need to know this stuff?

Things that make you go hmmm

It seems incredible that we can email a photograph around the world, but we haven't yet found an easy way of transmitting an ECG to a nearby hospital.

- Ivan Rokos, MD to heartwire [1]

Question: What's the incentive for industry to invent a simple, cost effective method for transmitting the prehospital 12 lead ECG to the hospital?

Dr. Rokos and Dr. Gibson discuss prehospital STEMI activation pathways

I don't know how I missed this, but click here to see a discussion between Dr. Rokos and Dr. Gibson regarding prehospital 12 lead ECGs. This was from LUMEN 2009.

Top 10 myths about prehospital 12 lead ECGs

A recent thread at JEMS Connect has reminded me how many myths are circulating about prehospital 12 lead ECGs.

1.) If you're close to the hospital, performing a PH12ECG is a waste of precious time.

The PH12ECG is an important triage tool. The closest hospital is not necessarily the closest appropriate hospital! In addition, just because you're close to a PCI hospital doesn't mean you can't save 15 minutes of ischemic time by giving the hospital early notification that you've identified a STEMI patient.

2.) PH12ECG monitors are incapable of capturing diagnostic quality 12 leads.

As long as the low frequency (high pass) filter is set to 0.05 Hz (which happens automatically when you capture a PH12ECG) then you will record accurate ST segments. A more important issue is data quality and lead placement, which is a training issue (and a credibility issue).

3.) It's important for the ED staff to perform another 12 lead ECG to confirm that it's really a STEMI.

I don't care if the ED staff performs another 12 lead ECG as long as the cath lab has already been activated based on the PH12ECG and they are already taking advantage of parallel processing (for those patients who show obvious STEMI in the field). However, there's nothing "magic" or "special" about the ED's 12 lead ECG. Serial ECGs can be extremely important, but mostly for suspected ACS patients with nondiagnostic (or borderline) ECGs on initial presentation. If they're waiting for their own 12 lead ECG before activating the cath lab, then they're wasting valuable time.

4.) If ST segment elevation resolves by the patient's arrival at the hospital, then it's not a STEMI, and the patient doesn't need an emergent cath.

Should you wait for the cardiac biomarkers to come back positive before sending the patient to the cath lab? I'm not sure that's a good idea. The case I posted last month shows that even when ST segment elevation resolves by arrival at the hospital, the patient can still have an occlusive thrombus in an epicardial coronary artery.

5.) Nitroglycerin is contraindicated for patients with suspected right ventricular infarct.

Not all patients with inferior STEMI have RV involvement, and not all patients with RV involvement develop the hypotensive syndrome. Consider the vital signs, the heart rhythm, and the physical exam, and treat accordingly. Sometimes the patient just needs a preemptive fluid bolus.

6.) PH12ECGs are important tools to help distinguish between VT and SVT with aberrancy.*

If you're using QRS morphology to "rule in" VT, then be my guest! If you're using it to justify giving a CCB to a patient with a wide complex tachycardia, then I think you're crazy. That's not to say that I don't capture 12 lead ECGs for all patients who present with cardiac arrhythmias, because I do. Documenting the arrhythmia is very important. Sometimes it even helps with the diagnosis. But I do not base my treatment decisions on QRS morphology and neither should you.

7.) If the hospital ignores the PH12ECG, then there's no point in performing one.

I'm sympathetic to this view, but it's a defeatist attitude. You should capture a PH12ECG with the first set of vital signs, prior to oxygen and nitroglycerin. That way, when you "clean up" the 12 lead ECG prior to arrival, you can hand them a picture of what the patient looked like prior to your intervention. It's hard to imagine that a board certified EM physician would ignore that. In any case, the ECG should be made a part of the patient's record, because the cardiologist may care.

8.) It's easy to identify STEMI on the PH12ECG.*

Technically this isn't a myth. It is easy to identify a home run STEMI on the PH12ECG. However, that should not be interpreted to mean that reading a 12 lead ECG is easy, or that just because you've been taught to identify an obvious STEMI with reciprocal changes that you can read an ECG as good as a physician. You might be able to, but you probably can't. Identifying ST segment elevation on the 12 lead ECG is easy! Differentiating between true STEMI and the STE-mimics can be difficult. Sometimes very difficult.

9.) It's impossible to identify STEMI in the presence of LBBB.

Sure you can. You can use a modified form of Sgarbossa's criteria and you can perform serial ECGs. A moving ST segment suggests dynamic supply vs. demand characteristics consistent with ACS. Is it difficult? It's more difficult. Impossible? Hardly.

10.) Axis determination is "nice to know" information but paramedics don't really "need to know" it.

That's like saying "paramedics don't really need to know how to read a 12 lead ECG." That's fine, if that's really your opinion. Just don't complain when you're asked to transmit the ECG for physician interpetation.

* Technically not a myth but requires qualification.

New interpretive statement on the Lifepak 15

I couldn't help but notice that in Physio-Control's new video the LP15 says ***MEETS ST ELEVATION MI CRITERIA*** and not ***ACUTE MI SUSPECTED***.

Interesting.

***Update 04/24/09***

See the new spec sheet here (.pdf) which specifically highlights the new interpretive statement.

I even found the article I wrote with Dr. Rokos listed in the references (#14).

AHA Mission: Lifeline video

Click here to see the new video from AHA Mission: Lifeline. I think they did a fantastic job!

66 yom CC: Syncope x3

You are dispatched to an "unknown medical complaint." En route to the scene, dispatch advises you that a 66 year old male is complaining of a fall with injury, chest pain, left arm pain, and nausea.

On arrival, the patient is standing in his kitchen. He is pale and extremely diaphoretic. You direct him to a chair so you can obtain a history of the present illness.

The patient states that he "passed out" in the bathroom the night before and twice this morning. The most recent episode was in the kitchen just before the patient's spouse contacted 9-1-1.

The patient states he has always been healthy except for a "little bit of high blood pressure", high cholesterol, and "a right bundle branch block which is at least 20 years old." There is no other history of syncope or falls.

The patient is alert and oriented to person, place, and time, but he admits that he is "foggy" with regard to the syncopal episodes. However, he denies hitting his head and states he has no head or neck pain. His C-spine is cleared.

A 2 cm horizontal laceration is noted under the patient's chin. He doesn't remember the last time he had a tetanus shot. He is also complaining of posterior rib pain on the right side. The pain is worse with inspiration and palpation but the chest wall is stable. He denies any other chest discomfort. He denies shortness of breath. He denies arm pain. He is not nauseated at the time of EMS evaluation.

Vital signs are assessed.

Pulse: 90
Resp: 16
BP: 105/60
SpO2: 96 on RA

Breath sounds: clear bilaterally

The cardiac monitor is attached.


A 12 lead ECG is captured.


By this time the patient "feels better." He is no longer diaphoretic and he thinks he'll "be okay."

The patient is adamant that he does not want to be transported to the hospital.

Do you think he needs to go to the hospital?

What do you think is causing his syncope?

How do you explain to the patient the risk he is taking by refusing care?

AHA Mission: Lifeline Recommendations for Criteria for STEMI Systems of Care

Mission: Lifeline Recommendations for Criteria for STEMI Systems of Care

The criteria are divided into:

• Non-PCI Hospital/STEMI Referral Center
• PCI Hospital/STEMI-Receiving Center sections
• EMS
• STEMI Systems of Care

Non-PCI Hospital/ STEMI Referral Center

1. Appropriate protocols and standing orders should be in place for the identification of STEMI. At a minimum, these protocols should be present in the Intensive Care Unit/Coronary Care Unit and Emergency Department (ED)
2. Each ED should maintain a standardized reperfusion STEMI care pathway that designates primary PCI as the preferred reperfusion strategy if transfer of patients to a primary PCI hospital/STEMI-Receiving Center can be achieved within times consistent with ACC/AHA guidelines.
3. Each ED should maintain a standardized reperfusion STEMI care pathway that designates fibrinolysis in the ED (for eligible patients) when the system cannot achieve times consistent with ACC/AHA guidelines for primary PCI.
4. If reperfusion strategy is for primary PCI transfer, a streamlined, standardized protocol for rapid transfer and transport to a STEMI-Receiving Center should be operational.
5. If reperfusion strategy is for primary PCI transfer, all patients should be transported to the most appropriate STEMI-Receiving Center where the expected first door-to-balloon (first device used) time should be within 90 minutes (considering ground versus air transport, weather, traffic).
6. The STEMI Referral Center should have an ongoing quality improvement process, including data measurement and feedback, for the STEMI population and collect and submit Mission: Lifeline required data elements (using the Mission: Lifeline Bridging form).
7. A program should be in place to track and improve treatment (acutely and at discharge) with ACC/AHA guideline based Class I therapies.
8. A multidisciplinary STEMI team, including EMS, should review hospital specific STEMI data on a quarterly basis.
1. Door-to-first ECG time (goal <10>
2. Proportion of STEMI-eligible patients receiving any reperfusion (PCI or fibrinolysis) therapy
3. STEMI Referral Center ED door-to-balloon (first device used) time for patients transferred to PCI center
1. STEMI Referral Center ED door to ED discharge
2. STEMI Referral Center ED door-to-balloon (first device used) time within 90 minutes (including transport time)

* The Mission: Lifeline Bridging Form is being developed for the use of STEMI Referral Hospitals and will focus on abbreviated STEMI emergency treatment, process times, and discharge data.

Primary PCI Hospital/ STEMI-Receiving Center

1. Protocols for triage, diagnosis and Cardiac Catheterization Laboratory activation should be established within the primary PCI hospital/STEMI-Receiving Center. A single activation phone call should alert the STEMI team. Criteria for EMS activation of the Cardiac Catheterization Laboratory should be established in conjunction with EMS offices.
2. The STEMI-Receiving Center should be available 24 hours/7 days a week to perform primary PCI.
3. The Cardiac Catheterization Laboratory staff including interventional cardiologist should arrive within 30 minutes of activation call.
4. There should be universal acceptance of STEMI patients (no diversion). There should be a plan for triage and treatment for simultaneous presentation of STEMI patients.
5. Interventional cardiologists should meet ACC/AHA criteria for competence. Interventional cardiologists should perform at least 11 primary PCI procedures per year and 75 total PCI procedures per year.
6. The STEMI-Receiving Center should meet ACC/AHA criteria for volume and perform a minimum of 36 primary PCI procedures and 200 total PCI procedures annually.
7. The STEMI-Receiving Centershould participate in the Mission: Lifeline-approved data collection tool, ACTION Registry-GWTG^TM.
8. A program should be in place to track and improve treatment (acutely and at discharge) with ACC/AHA guideline based Class I therapies.
9. There should be a recognized STEMI-Receiving Center liaison/system coordinator to the system and a recognized physician champion.
10. There should be monthly multidisciplinary team meetings to evaluate outcomes and quality improvement data. Operational issues should be reviewed, problems identified, and solutions implemented. The following measurements should be evaluated on an ongoing basis:
    a. Door-to-balloon (first device used) time, non-transfer within 90 minutes
    b. STEMI Referral Hospital ED door-to-balloon (first device used) time, transfer within 90 minutes
    c. First Medical contact to balloon inflation (first device used) non-transfer within 90 minutes
    d. First Medical contact to balloon inflation (first device used) transfer
    e. Proportion of eligible patients receiving reperfusion therapy
    f. Proportion of eligible patients administered guideline-based Class I therapies
    g. Proportion of patients with field diagnosis of STEMI and activation of the Cardiac Catheterization Laboratory for intended primary PCI that
    i. do not undergo acute catheterization because of misdiagnosis
    ii. undergo acute catheterization and found to have no elevation in cardiac biomarkers and no revascularization in the first 24 hours
    h. In-hospital mortality

EMS

1. Each EMS system should maintain a standardized algorithm for evaluating and treating patients with symptoms suggestive of myocardial ischemia that should include acquisition of a 12-lead ECG and appropriate communication of the ECG findings (via direct paramedic interpretation/voice communication, automated computer algorithm interpretation, wireless transmission and physician interpretation, or any combination of these three strategies) to the receiving hospital.
2. Each EMS system should maintain a standardized reperfusion STEMI care pathway that designates primary PCI as the preferred reperfusion strategy if initiated within 90 minutes of first medical contact or fibrinolytic therapy in eligible patients when primary PCI within 90 minutes is not possible.
3. Prearranged EMS destination protocols for STEMI patients should include:
   a. Bypassing non-PCI hospitals/STEMI Referral Centers and going directly to primary PCI hospitals/STEMI-Receiving Centers for patients with anticipated short transport interval (e.g. <30 minutes in urban/suburban settings, so as to achieve primary PCI within 90 minutes)
   b. Emergency transfer by EMS or other agencies to a STEMI-Receiving Center of patients with STEMI who transport themselves to a STEMI Referral Center.
   c. Air transport if possible (or default to ground transport ) to STEMI-Receiving Center or stabilization in STEMI Referral Center for patients with anticipated long transport time and/or either fibrinolytic ineligible and/or in cardiogenic shock
   d. Administration of fibrinolytic therapy prehospital or in a STEMI Referral Center for fibrinolytic eligible patients with anticipated time to primary PCI exceeding 90 minutes
   e. Emergency transfer to a STEMI-Receiving Center of patients who develop STEMI while in hospital at STEMI Referral Center (non-PCI hospital).
4. When taken directly to a STEMI-Receiving Center, all STEMI patients should be transported to the most appropriate facility as determined by Mission: Lifeline hospital criteria, with a system goal of first medical contact to balloon inflation (initial device used) within 90 minutes.
5. EMS medical director or designate should monitor care related to EMS patients with STEMI by meeting at least quarterly with prehospital providers, emergency physicians, interventional cardiologists, nursing staff, receiving hospital representatives, and other appropriate individuals (i.e. STEMI Survivor).
6. The following measurements should be evaluated on an ongoing basis:
   a. Symptom onset to 9-1-1 call
   b. Time 9-1-1 call is first received by primary public safety answering point to vehicle arrival at hospital door
   c. Time from first medical contact to balloon inflation (first device used).
   d. Time from prehospital ECG to balloon inflation (first device used).
   e. Proportion of patients with non-traumatic chest pain > 35 years treated by EMS for whom 12-lead ECGs were obtained
   f. Proportion of patients with STEMI treated by EMS for whom 12-lead ECGs were obtained
   g. Proportion of patients with field diagnosis of STEMI and activation of the Cardiac Catheterization Laboratory for intended primary PCI that
   i. do not undergo acute catheterization because of misdiagnosis
   ii. undergo acute catheterization and found to have no elevation in cardiac biomarkers and no revascularization in the first 24 hours
   h. Proportion of patients with EMS treated ventricular fibrillation (VF) who are taken to the Cardiac Catheterization Laboratory
   i. Survival to hospital discharge of all STEMI patients and of patients with VF (EMS and STEMI-Receiving Center to monitor jointly)

STEMI Systems of Care (All five must be present in order to be certified)

1. The System should be registered with Mission: Lifeline.
2. There should be on-going multidisciplinary team meetings that include EMS, non-PCI hospitals/STEMI Referral Centers, and PCI hospitals/STEMI-Receiving Centers to evaluate outcomes and quality improvement data. Operational issues should be reviewed, problems identified, and solutions implemented.
3. Each STEMI System should include a process for pre-hospital identification and activation, destination protocols to STEMI Receiving Centers, and transfer for patients who arrive at STEMI Referral Centers and are primary PCI candidates, and/or are fibrinolytic ineligible and/or in cardiogenic shock.
4. Each system should have a recognized system coordinator, physician champion, and EMS medical director.
5. Each system component (EMS, STEMI Referral Centers and STEMI-Receiving Centers) should meet the appropriate criteria listed above.

Posted March 26, 2009 http://www.americanheart.org/presenter.jhtml?identifier=3061630