August 2014: Right behind you with a STEMI!

A 60 yo male patient reports a sudden onset of chest pain and shortness of breath. The patient rates the pain at an 8/10 and is slightly nauseated. The patient has a history of "borderline" diabetes.

VS:
BP: 140/90, P: 62, R: 16, Sp02: 99%

EXAM:
The patient is slightly diaphoretic and appears uncomfortable. A 12 lead ECG is obtained.

ACTIONS:Do you activate the cath lab?
Do you administer NTG?

12 LEAD ECG: 

12 LEAD ECG CASE DISCUSSION:

The ECG shows a first degree heart block. ST segment elevations are apparent in Leads II, III, and aVF. Reciprocal changes are present in Leads I and aVL. ST segment changes are present in the septal leads of V3 to V4. The diagnosis of a posterior wall myocardial infarction is less likely given (1) the absence of tall R waves and (2) The absence of ST depression in leads V1-V3. However, anytime anterior precordial ST depression appears concurrently with an inferior wall MI, you should consider the diagnosis of a posterior wall infarction. Recall that the posterior descending coronary artery comes from the right coronary artery. It is wise to be cautious with nitroglycerin since this infarction may involve portions of the right ventricle. Have IV access established and consider right sided chest leads if there is concern for a right ventricular infarction. This patient went emergently to the cardiac catheterization lab and was found to have a completely (100%) occluded right coronary artery.  Finally, conduction delays and heart blocks are consistent with ischemia of the sinoatrial node and the conduction system.

12 LEAD ECG INTERPRETATION:
Inferior wall ST elevation myocardial infarction.

Pointy ST Segments and Abnormal Labs

Your crew responds to a local skilled nursing facility for a patient with "abnormal labs." The nurse tells you that the patient's "K was elevated." The patient reports a near syncopal episode approximately 40 minutes prior to arrival. The patient feels weak and dizzy. No chest pain, shortness of breath, or vomiting is endorsed. The patient is ill appearing but awake, alert, and oriented.

Vital signs:
BP: 82/40
P: 49
R: 16
Sp02: 86% on room air

A 12 lead ECG is obtained:

12 Lead ECG Discussion

The rhythm is sinus bradycardia. Unless this 80 year old is a marathon runner, the rate is abnormal. Furthermore, the bradycardia occurs in association with (1) near syncope and (2) abnormal vital signs. ST segment elevation is seen in leads II, III, and aVF. Reciprocal change in the form of ST segment depression is seen in lead aVL. STE is also observed in the lateral precordial leads. The R waves are tall in V2 and V3 but there is no concurrent ST segment depression to suggest involvement of the heart's posterior wall. Q waves, though not pathologic, appear in leads II, III, and aVF, and favor the diagnosis of ischemia.

12 Lead ECG Interpretation 

Sinus bradycardia, Inferior-lateral ST segment myocardial infarction. 

Case Discussion

This case presents more than a few dilemmas and teaching points. First, it emphasizes the association between dizziness, weakness, and acute coronary syndromes. Elderly patients may not present with the classic "chest pain" or "chest pressure." Dyspnea, dizziness, and weakness are well known anginal equivalents and should be aggressively investigated, especially in the setting of abnormal vital signs. The presence of peaked T waves might suggest underlying hyperkalemia. The changes associated with hyperkalemia are usually diffuse. The STE in this ECG follows an anatomic (inferior-lateral) pattern. If there is concern for "abormal labs," then the administration of calcium is probably warranted. Calcium should always be considered first line in the management of hyperkalemic emergencies.

What About the Rate? 

This patient also presents with symptomatic bradycardia. A well accepted axiom in EMS and emergency medicine is, "fix the rate FIRST." EMS protocols would probably advocate for a healthy dose of atropine. Ischemia of the SA node (caused by RCA occlusion) can certainly result in a symptomatic bradycardia, heart blocks, and other types of badness. However, be cautious when administering atropine to a patient suffering from an active MI. Atropine will increase myocardial demand and have the potential to exacerbate ischemic symptoms. A gentle fluid bolus may suffice to mitigate hypotension, and opening of an occluded RCA will make everything right as rain...

KEY POINTS:

• Fix the rate first (WITH CAUTION in cases of active ischemia!) 
• Calcium is first line in the treatment of suspected hyperkalemia and ECG changes
• Weakness, dizziness, and syncope should be regarded as anginal equivalents- especially in the elderly 
• Inferior wall myocardial infarction can produce bradycardia, heart blocks, and syncope

Special thanks to JoElyn for providing these ridiculously complex ECGs! (And best wishes as a newly minted registry medic...) 

There's STE in V1 !

EMS responds to the report of a 77 year old male with chest pain. The patient is hypertensive, alert, and hemodynamically stable. Aspirin and nitroglycerin are administered per treatment protocol. A 12 lead ECG is obtained, and the paramedic asks about transport to the closest hospital versus a facility capable of percutaneous coronary intervention...


12 lead ECG



12 lead ECG Discussion

There is a baseline sinus rhythm. The rhythm is regular. Close scrutiny of lead II and V1 reveals the presence of p waves. The ST segments are upright in most leads with the exception of aVR. The QRS duration is slightly prolonged consistent with an interventricular conduction delay. The (1) positively deflected QRS in lead V1 and the (2) lengthened QRS duration suggests the presence of a RIGHT bundle branch block. There is a subtle slurred l S wave in V6 which further corroborates the diagnosis of a right bundle branch block.

The Slurred S Wave

12 lead ECG Interpretation

Sinus rhythm, right bundle branch block, rate of approx 80 beats/min.

Case resolution

The patient was transported to a local facility. Serial ECGs remained unchanged and cardiac enzymes were normal. The patient was discharged to home following an overnight hospital stay and a cardiac stress test.