Hilton Head Island Fire & Rescue 12-lead ECG Case of the Month October 2009 STEMI Program

EMS is called to a community event for a 52 year old male who experienced a syncopal episode. An engine company arrives at the scene. The patient is found slumped back in a chair with a cold, moist towel on his head. His eyes are closed, he is groaning, and appears acutely ill with pale and diaphoretic skin. Bystanders say that he passed out and hit his head. There are minor abrasions to the top of his head. When asked whether or not he passed out, the patient says, "I think so." His chief complaint is chest discomfort. Onset : Symptoms started about 30 minutes ago while setting up a concession stand. Provoke : Nothing makes the pain better or worse. Quality : Pain is described as a constant pressure. Radiate : The pain does not radiate. Severity : The patient gives the pain a 5/10. Time : No previous episodes.

Past medical history: Unknown. Patient states he has never been to the doctor. Meds: None. Vital signs are assessed: Resp: 18 Pulse: 64 BP: 108/78 The patient is placed on oxygen via NRB mask @ 15 LPM. The medic unit arrives on scene. The patient is relocated to the ambulance and undressed from the waist-up. SpO2: 97 on RA

The cardiac monitor is attached at 12:15:55 The rhythm is sinus arrhythmia with P waves and QRS complexes in a 1:1 relationship.

12-Lead 1 is captured at 12:17:47 The data quality is excellent and the GE-Marquette 12SL interpretive algorithm is giving the ***ACUTE MI SUSPECTED*** message.

Critical question! Do we agree with the computer’s assessment?

ST-segment elevation present?

Yes! ST-segment elevation > 1 mm is present in leads I and aVL. ST-segment elevation > 2 mm is present in leads V2 and V3. ST-segment elevation > 1 mm is present in leads V4 and V5.

Are leads I, aVL, V2, V3, V4 and V5 anatomically contiguous?

Yes!

Why?

Leads I and aVL are the “high lateral” leads and are contiguous. V6 Lateral V3 Anterior aVF Inferior III Inferior V5 Lateral V2 Septal aVL Lateral II Inferior V4 Anterior V1 Septal aVR I Lateral

Leads V3 and V4 are the anterior leads and are contiguous. V6 Lateral V3 Anterior aVF Inferior III Inferior V5 Lateral V2 Septal aVL Lateral II Inferior V4 Anterior V1 Septal aVR I Lateral

What about leads V2 and V5?

Even though V2 is a septal lead and V5 is a lateral lead, they are “connected together” by the ST-elevation in leads V3 and V4! V6 Lateral V3 Anterior aVF Inferior III Inferior V5 Lateral V2 Septal aVL Lateral II Inferior V4 Anterior V1 Septal aVR I Lateral

Any two precordial leads next to one another are considered anatomically contiguous!

V1 V2 V3 V4 V5 V6

Are reciprocal changes present?

I, aVL II, III, aVF INFERIOR V1, V2, V3, V4 NONE POSTERIOR II, III, aVF I, aVL, V3, V4, V5, V6 ANTEROLATERAL II, III, aVF I, aVL, V5, V6 LATERAL NONE V1, V2, V3, V4 ANTEROSEPTAL NONE V3, V4 ANTERIOR NONE V1, V2 SEPTAL RECIPROCAL FACING SITE

Reciprocal ST-segment depression is present in leads III and aVF. Yes!

STEMI Alert criteria met?

Patient has signs and symptoms of ACS 12 lead ECG shows excellent data quality Computer reads ***ACUTE MI SUSPECTED*** Paramedic agrees with computer interpretation QRS duration is < 120 ms (0.12 s) ECG shows 1 mm of ST-segment elevation in 2 or more contiguous leads (2 mm in leads V2 or V3) Reciprocal changes are present Contact dispatch and announce “STEMI Alert” Transmit the ECG to the emergency department

Yes! and Yes! At this point the EMS crew has all the information they need to contact dispatch and announce “STEMI Alert!” The ECG should be transmitted to the hospital immediately.

When you call in, the only information you are required to give is the following: Your name and medic unit call sign The fact that it is a STEMI Alert The first and last name of the patient The patient’s date of birth The age, gender and chief complaint The vital signs Whether or not the patient has a preferred cardiologist It is assumed that STEMI patients will be treated according to protocol.

When you call in, the only information you are required to give is the following:

Your name and medic unit call sign

The fact that it is a STEMI Alert

The first and last name of the patient

The patient’s date of birth

The age, gender and chief complaint

The vital signs

Whether or not the patient has a preferred cardiologist

It is assumed that STEMI patients will be treated according to protocol.

Clinical pearl

Generally speaking, the more leads showing ST-segment elevation, the higher the mortality!

Figure 1: Effects of thrombolytic therapy on mortality (lives saved/1000 treated) in various patient subgroups according to admission ECG. Based on data from FTT Collaborative Group. This is a reproduction of a graph found in Management of Acute Coronary Syndromes by Christopher P. Cannon, © 1999 Humana Press Inc. Anterior STEMI has a higher mortality than inferior STEMI! 49 37 8 -14 -7

What is the most common culprit artery with acute anterior STEMI?

Angiogram shows 100% occlusion of the left anterior descending artery (LAD).

Before After

Door-to-balloon (D2B) time: 43 minutes!