Cardiac Emergencies—Chest Pain, Stemi, ACS, CHF

1

Name some life-threatening causes of chest pain.

Chest pain can be due to a variety of causes. In the prehospital setting, it is always important to consider some of the more life-threatening etiologies to chest pain. Listed here are the “serious 6” concerning etiologies for chest pain:

• Tension pneumothorax

• Pulmonary embolism (PE)

• Ruptured esophagus

• Cardiac tamponade

• Aortic dissection

• Acute coronary syndrome (ACS)

2

What are some initial questions to assessing the type of chest pain a patient is experiencing?

Having a good description of the chest pain can help identify the etiology of the symptoms. Asking about duration of symptoms, quality, intensity, frequency, location, and if it radiates to other parts of the body is a good start. In addition, identifying the precipitating factors or associated symptoms can provide important clues.

3

What are some initial steps in your physical exam to assessing chest pain in the prehospital setting?

It is important to always start by assessing the patient’s heart rate and breathing. If the patient is tachycardiac (fast heart rate) or tachypneic (fast breathing), it could be signs of heart or lung pathology. In general, a heart rate above 100 beats per minute and respirations over 20 respirations per minute are abnormal . Checking a pulse and observing respirations can be very helpful to determine how sick a patient is. Next, auscultating the heart and lungs can help guide management.

4

What are some findings that can be suggested with an electrocardiogram (EKG)?

An EKG can detect and suggest many things clinically. One of the main reasons to obtain an EKG is to assess for ST-segment elevation myocardial infarction (STEMI) and ACS; however, there are EKG findings that can suggest pericardial effusion, pericarditis, PE, heart failure, left ventricular aneurysm, hypothermia, and electrolyte abnormalities (i.e., hyperkalemia, hypercalcemia, etc.). For this reason, an EKG should be performed on all patients with the complaint of chest pain or shortness of breath.

1

What is a STEMI?

STEMI stands for ST-segment elevation myocardial infarction. A STEMI is an episode of transmural infarction involving the entire thickness of the myocardium, demonstrated on EKG.

2

What are the EKG findings for a STEMI?

• 1 mm of ST-segment elevation in two or more anatomically continuous leads (see Fig. 15.2 ) with reciprocal depression over areas opposite to the ST-segment elevation, or of injury.

• Isolated ST-segment depression in V1–V4 is an indication of posterior STEMI and should be evaluated with a posterior lead EKG.

3

What parts of the heart correlate to EKG findings where a STEMI can be located?

Different areas on the EKG correlate with different regions of the heart.

• Septal: V1 and V2

• Anterior: V3 and V4

• Lateral: V5 and V6

• Anteroseptal: V1–V4

• Anterolateral: V3–V6

• Extensive anterior: V1–V6

• Inferior: II, III, aVF

• High lateral: I, aVL

• Posterior: tall R wave and ST depression in V1–V2

4

What are some STEMI mimics that could cause ST-segment elevation?

It is important to consider other causes of ST-segment elevation on an EKG other than a STEMI, especially when the patient’s complaints do not correlate with typical ACS symptoms.

• Left ventricular hypertrophy

• Early repolarization

• Acute pericarditis

• Cor pulmonale

• Hyperkalemia

• Hypercalcemia

• Hypothermia

• Left ventricular aneurysm

5

What medications should be given to a patient with a STEMI or ACS?

In patients with possible STEMI or ACS, aspirin should be given. A dose of 160–325 mg PO or PR is acceptable. Aspirin alone can lead to a 23% reduction in mortality.

Other medications that can help in the prehospital setting are as follows:

• Nitroglycerin for persistent chest pain (typically 0.4 mg sublingual, every 5 minutes for three doses as needed)

• Morphine for persistent chest pain (typically 0.1 mg/kg, or a 4-mg dose)

• Supplemental oxygen if the patient is hypoxic

Other medications such as heparin, clopidogrel, and abcixmab are best utilized in a hospital setting in collaboration with the emergency medicine physician and a cardiologist.

6

What is percutaneous coronary intervention (PCI)?

PCI is a procedure that uses a catheter inserted into a patient’s femoral or radial artery to gain direct visualization of the patient’s coronary arteries with dye injection. Primary PCI is utilized to treat STEMIs and other forms of myocardial infarctions. This is accomplished by placing a stent or angioplasty to open the narrowing of the coronary artery.

7

In patients with a STEMI, what are the recommendations for PCI?

The American Heart Association recommends PCI as the preferred treatment for STEMI or ACS. Expected first medical contact to first balloon inflation time is ≤90 minutes . From a prehospital standpoint, it is important to know which facilities have PCI capabilities.

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