The Agony of the Beta Agonists PART 1 of 2 JULY 2015

This was shared from a friend, provider, and colleague. Interesting case. Details changed to protect the innocent, respect privacy laws, comply with all appropriate regulations, and, well.. you get the picture.

SUBJECTIVE
HPI:
94 yo male requests 911 for shortness of breath. HPI  not obtainable due to patient presenting in extremis. The patient is alert, responsive to verbal stimuli, and is in obvious respiratory distress upon arrival. Providers appreciate audible wheezing. Family members relate that the patient is a "DNR" and was last seen acting "a little tired" 12 hours prior.
Meds: Unknown
PMH: COPD, CHF, HTN, HLD, DM

OBJECTIVE
Pt is slightly diaphoretic. BP: 134/92, R: 32, P: 90. ETC02 via NC is 20.
Supraclavicular and intercostal retractions are present as is mild JVD.

12 LEAD ECG:












Case related questions: 
1. What is your prehospital treatment?
2. What are some concerning ECG findings?
3. Is this patient treated as a STEMI alert?

Simple STain on the Strain

Sometimes LVH isn't all that simple. The "strain" pattern has been discussed elsewhere on this and other blogs, but this is an example of an atypical, and concerning, ECG:

What's not (so) unusual: 
The ECG reveals a sinus rhythm. The downsloping ST segments and T wave inversions seen in the lateral leads and precordial leads may be expected in the setting of high left ventricular voltage. The pattern of LVH and ST/T wave changes is consistent with, "strain."

What's concerning: 
The ST segment elevation present in aVL and V1-V2 is NOT concave and almost horizontal. This type of ST segment change is consistent with ischemia. Furthermore, it appears in an anatomic distribution. ST segment changes in aVL and V1-V2 suggest anterior or anterior lateral ischemia. Though LifeNET measures the ST segment elevation at less than 2 mm, it is nevertheless cause for concern especially given a "typical" story or history consistent with an acute coronary syndrome.

Bottom line and interpretation:
Carefully evaluate ST segment deviation in all leads. Look for atypical elevation and an anatomic distribution of the ECG changes.
Sinus rhythm, ST segment depression and T wave inversion consistent with strain pattern. ST segment elevation in the anterior precordial leads and aVL suspicious for STEMI. 

The Power of the 12th Lead

EMS responds to the home of a 70 yo female patient. She reports severe, left-sided chest pain and mild shortness of breath.  Her skin is warm and dry.  Her abdomen is soft and non-tender.  She denies any medical history.

Vital signs:
BP: 142/76
P: 75
R: 18

Sp02: 98%

12 Lead ECG:

12 Lead ECG Interpretation and Discussion:

There is a baseline sinus rhythm. The rate is approximately 75 beats per minute.

The ECG also reveals left anterior fascicle block as noted by the rS pattern in leads II, III, aVF, and Rs pattern in leads I and aVL.

There is left axis deviation as demonstrated by the predominantly positive QRS complex in lead I, and predominantly negative QRS complex in lead aVF.

There is ST segment elevation in leads aVR and V1. In addition, ST segment changes (flat, depressed, or T wave inversion) are present in essentially every other lead (reciprocal changes).  Simultaneous ST segment elevation in leads aVR and V1 may predict left main coronary artery, or left anterior descending artery occlusion, and is considered to be a STEMI equivalent.  Patients who present with ST segment elevation in leads aVR and V1 should be transported to a facility capable of performing cardiac angioplasty.

Take-Home Points
Simultaneous ST segment elevation in leads aVR and V1 predicts LMCA or LAD occlusion
Patients should be transported to a cardiac intervention center and treated the same as STEMI

Well, I didn't see anything in the rhythm strip...

Case Description


Medics respond to the report of a 66 yo male with nausea, chest pain, and chest pressure radiating to the left arm. The patient appears well. Chest discomfort started 2 hours prior to EMS arrival. The patient's vital signs are as follows: BP: 168/100, P: 72, R: 60/regular. Sp02: 96% on RA. Physical examination is unremarkable. The patient is loaded for transport, and the paramedics consider aspirin and nitrates. A 12 lead ECG is obtained


12 lead ECG

12 Lead ECG Interpretation and Discussion 

The rhytm is sinus in origin, and there does not appear to be any ectopic beats. ST segments are upright with the exception of expected T wave inversion in lead aVR. Careful scrutiny of the inferior leads reveals subtle ST segment elevation of approximately 1 mm. ST segments should be measured at the "J" point, and there is just about 1 mm / 1 box of elevation in the inferior leads. Further substantiating the findings of ischemia are the ST segment elevations present in leads V2-V5. The ST segments takes on an almost horizontal appearance in V5 and the R wave progression is preserved. Reciprocal change in the form of ST segment flattening and depression appears in leads I and aVL. When deciding if any one ECG represents ischemic patterns look for (1 ) anatomic distribution of abnormal findings and (2) reciprocal changes. This ECG features both of these findings. This patient was transported for urgent PCI; I do not have angiographic findings available. The ST elevation in the limb leads is not all that impressive. It is easy to imagine that placing this particular patient "on the monitor" would interfere with the recognition of concerning ST-T changes in the precordial leads. 

Closer look at ST segment ugliness

12 Lead Interpretation

Sinus rhythm, rate of 60, widespread ST segment elevation in the inferior and anterior-lateral leads concerning for acute ischemia.

Pearls

• If there is ANY suspicion for coronary ischemia or cardiac-related chest pain, perform a complete 12 lead
• The presence of recipocal change makes the diagnosis of ischemia more likely
• Territorial ST-T changes (anterior, lateral, inferior) are similarly concerning for ischemia

Thoughts on another acute process that might produce widespread, diffuse STE? 

The Eclectic Equivalent

A 64 yo female calls 911 for chest discomfort. The patient reported chest pressure that waxed and waned in intensity. The discomfort was retrosternal and did not radiate. The patient compared the pressure to previous bouts of "indigestion." The patient experienced associated nausea. No LOC, no diaphoresis. Providers obtain a 12 lead ECG. Vital signs remained stable.

12 Lead ECG

12 Lead ECG Interpretation 

The rhythm is sinus and the rate is regular. ST depressions are present in leads II, III, and aVF. There are also ST depressions noted in the precordial leads V3-V6. R wave progression is preserved, and it appears that R waves reach their maximum amplitude in lead V4. There is no obvious ectopy.

ST elevation of > 1 mm is noted in aVR and V1.

Sinus rhythm, diffuse ST segment depression, ST segment elevation in aVR and V1.

Case Discussion

Providers correctly identify the ECG tracing as a potential STEMI equivalent. The STE in aVR and V1 is concerning for its association with acute left main occlusion. The patient was transported to the cardiac cath lab. Cardiologists discovered a near total occlusion of the left main coronary artery.

aVR has long been cast as the "forgotten lead" in electrocardiography. Studies link ST elevation in aVR to left main disease and cardiogenic shock. There is also data to suggest that patients with changes in aVR are more likely to require surgical intervention and progress into cardiogenic shock. Indeed, ST elevation in aVR is often considered a, "STEMI equivalent" due to its association with a poorer prognosis. Always scrutinize all leads of the electrocardiogram for abnormal ST segment morphology. In some studies, STE in aVR that is greater than the STE in V1 distinguishes left main disease from left anterior descending artery disease.

Findings such as STE in aVR are often labeled, "STEMI equivalents." Though not widely recognized as automatic triggers for cath lab activation, these concerning electrocardiographic findings represent time sensitive conditions that benefit from an early interventional approach. Other equivalents include:

• Posterior wall MI (ST depression anteriorly)
• New left bundle in association with chest pain/ACS history 
• Hyperacute T waves
• The deWinter ST/T complex
• Positive Sgarbossa criteria

References
1. Yamaji H, Iwasaki K, Kusachi S, et al. Prediction of acute left main coronary artery obstruction by 12 lead electrocardiography. ST segment elevation in lead aVR with less ST segment elevation in lead V1. J Am Coll Cardiol. 2001;38(5):1348-54

2. Nough H, Jorat MV, Varasteravan HR, et al. The value of ST segment elevation in lead aVR for predicting left main coronary artery lesion in patients suspected of acute coronary syndrome. Rom J Intern Med. 2012;50(2):159-64

3. Nikus KC, Eskola MJ. Electrocardiogram patterns in acute left main coronary artery occlusion. J Electrocardiol. 2008;41(6):626-9

A Serial Case

An elderly male patient is transported to the emergency department following a syncopal episode. The patient reported feeling lightheaded, and experienced two witnessed syncopal episodes lasting for several minutes. Symptoms were made worse when standing up. The patient denied chest pain and reported some mild dyspnea. The patient had been in his usual state of health. The patient's medical history is significant for a tibial fracture several months prior.

Vitals:

Afebrile

BP: 72/P

P: 100

R: 24

Sp02: 92%, poor waveform, on NRB

Physical exam:

Pt is diaphoretic and alert.

Lungs are clear bilaterally.

The patient's abdomen is soft and non tender.
No evidence of lower extremity edema.

(Prehospital) 12 lead ECG:

Upon arrival at the hospital, large bore IV access was secured. A FAST (Focused Assessment with Sonography for Trauma) exam revealed no obvious free fluid and no obvious pericardial effusion. The abdominal aorta appeared grossly normal. The patient remained alert and responded to a bolus of IV crystalloid. A repeat ECG was obtained following another pre-syncopal event in the emergency department.

12 Lead ECG Interpretation and Discussion

On the repeat ECG, a sinus rhythm is present. The electrical axis is physiologic. Artifact interferes with the tracing in the inferior limb leads. ST segment elevation is present in aVR, V1, and V2. The ST segments appear horizontal in shape. That particular morphology is concerning for ischemia. While some mild ST segment depression is present in lead I, there are no clear cut reciprocal changes. The evolving changes suggest a septal wall myocardial infarction.

Final Interpretation

Sinus tachycardia, septal ST segment elevation myocardial infarction

(WRONG!)

Case Conclusion

The patient was transported emergently to the cardiac catheterization lab. The patient's coronary arteries were CLEAN and without evidence of disease. An emergent echocardiogram showed a severely dilated right ventricle with concurrent diastolic dysfunction. The clean coronary arteries and echocardiograpghic findings combined point to a massive pulmonary embolism as the cause of the patient's symptoms. Another subtle clue to this diagnosis was the hypoxia that persisted with high flow oxygen administration.

Though not all that elevates is a STEMI, field providers should nevertheless focus on identifying worrisome ST segment changes. The patient's initial ECG was somewhat non-specific. Though close inspection can reveal some slight ST segment elevation of less than 1mm in aVR and V1, it certainly did not meet standardized criteria for STEMI. The second ECG, however, represents a clear-cut evolution. ST segments have become more pronounced (elevated) in the septal leads. The increase in elevation combined with the horizontal plateau of the ST segments in leads V1-V2 suggest an evolving myocardial infarction- or an alternative diagnosis.

The patient presented with a syncopal episode and profound hypotension. Any number of emergent medical conditions can present with those complaints. Pulmonary embolism, internal bleeding, and aortic dissection must be considered in the initial assessment of the hypotensive patient. Unfortunately, there are no "classic" electrocardiographic findings associated with a large PE. That said, the following features can be seen in the setting of a pulmonary embolism.

PULMONARY EMBOLISM ECG FINDINGS

• Sinus tachycardia
• Right bundle branch block or incomplete right bundle branch block
• Deep S wave in lead I, Q wave in lead III, and an interveted T wave in lead III (S1, Q3, T3)
• T wave inversions
• Right axis deviation
• ST segment deviation (depression and elevation)

Sinus tachycardia and right bundle branch block may suggest "heart strain." These are electrical manifestations caused by the right ventricle that is pumping against a greatly increased pulmonary resistance.

aVR Rears its Ugly Elevation

A cardiologist's office calls 911 for an elderly patient who suffered a syncopal episode. The patient presented to the physician's office for a few weeks of bilateral arm pain and fatigue. The patient experienced mild dyspnea on exertion and was undergoing a chemical stress test when he experienced a brief syncopal episode. The patient was pain free at the time of EMS arrival. The patient was awake and alert. Vital signs:
BP: 104/70
P: 100
R: 22/non labored
Sp02: 96%

The cardiologist suggested transport to a facility capable of percutaneous coronary intervention. Why was the cardiologist so concerned (aside from the presence of an elderly patient with syncope in his office)? What's going on with this ECG?

12 lead ECG

12 Lead Interpretation and Discussion

The patient's rhythm is a borderline sinus tachycardia. ST segment elevation is present in leads aVR and V1. Diffuse ST segment elevation is present in the inferior and lateral leads. Though ST segment elevation in lead aVR isn't typically considered a "STEMI," there is sufficient evidence in the emergency cardiology literature that it should be considered as a "STEMI equivalent." ST segment elevation of > 1 mm (or > 0.5 mm in some studies) is associated with obstruction of the left main coronary artery. Furthermore, these patients are more likely to require surgical revascularization (CABG) or experience congestive heart failure. The skilled paramedic will easily recognize the widespread and diffuse ST segment abnormalities. This patient requires evaluation at a facility capable of percutaneous coronary intervention.

Final 12 lead ECG Interpretation

Sinus rhythm, ST segment elevation in leads aVR and V1. Probable acute obstruction of the left main coronary artery. Diffuse ST segment depression in the inferior (II, III, aVF), anterior (V4-V6), and lateral (I, aVL) leads.

Suggested Readings

• Rokos IC, French WJ, Mattu A et al. Appropriate cath lab activation: optimizing electrocardiogram interpretation and clinical decision making for acute ST elevation myocardial infarction. Am Heart Journ. Dec 2010;160(6):995-1003

• Barrabes JA, Figueras J, Moure C, et al. Prognostic value of lead aVR in patients with a first non ST segment elevation acute myocardial infarction. Circulation. 2003;108(81):814-819

• Williamson K, Mattu A, Plautz CU. Electrocardiographic applications of lead aVR. Am J Emerg Med. 2006;24:864-874

The Forgotten 12th Lead

A 70 yo patient presented to the ED with chest discomfort, diaphoresis, and nausea. The patient had a history of coronary artery disease and was hemodynamically stable. The patient stated that his retrosternal discomfort was similar his previous "heart attacks." The patient was pain free by the time he was moved into a monitored bed. An initial troponin level sent from triage was negative. Here's the triage EKG:

12 lead EKG interpretation
Sinus rhythm, diffuse ST segment depression, ST segment elevation in lead aVR

Discussion
The ECG, coupled with the patients presentation, is concerning for ischemia. At first glance, this ECG does not meet criteria for activation of the cath lab. A closer look at this ECG reveals cause for concern. There is ST segment elevation present in lead aVR. Often forgotten, overlooked, and otherwise thrown away, lead aVR provides important cluses to underlying cardiovascular disease. ST segment elevation in lead aVR may actually predict acute occlusion of the left main coronary artery. Specifically, STE in aVR that is LESS than STE present in lead V1 is associated with left main occlusion.

References
Gorgels APM, Engelen DJM, Wellens HJJ. Lead aVR a mostly ignored but very valuable lead in clinical electrocardiography. J Am Coll Cardiol. 2001;38:1355-1356
http://content.onlinejacc.org/cgi/content/full/38/5/1355
Mattu A. Lead aVR: importance of the "forgotten 12th lead" in patients with ACS. Medscape Emergency Medicine. 2009. Available at: http://www.medscape.com/viewarticle/589781. Accessed February 2012

Hey! Its me in V3!

This may look like your ordinary inferior wall MI, but the expert ECG clinician will spot another potential indication to bypass the local ED in favor of a cath-capable facility... Don't look too closely!

12 lead ECG Interpretation

Sinus rhythm, inferior wall myocardial infarction

Discussion

Classic inferior wall changes are present in leads II, III, and aVF. STE of greater than or equal to 1mm is consistent with the field impression of ST elevation myocardial infarction. In addition, there's some ST segment depression (reciprocal change) in lead aVL.
Lead V3 also reveals a concerning finding: upsloging ST segment depression. This subtle, but important finding, usually indicates acute occlusion of the proximal LAD. The upsloping ST segments usually appear with tall and upright T waves in the anterior precordial leads.

Learn more about the de Winter ST/T wave complex here:
http://www.ahjonline.com/article/S0002-8703(10)00758-1/fulltext#s0040