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Bradycardia

Bradycardia

Assume a Cardiac Cause Until Proven Otherwise

Pregerson, Brady MD

doi: 10.1097/01.EEM.0000815556.43364.9c
    ECG, GERD, retrosternal burning, catheterization
    ECG, GERD, retrosternal burning, catheterization:
    Image 1. The patient's first ECG taken in triage.
    Figure
    Figure

    A man in his mid-50s with no previous medical history presented to the hospital with about an hour of retrosternal burning that was improving but not resolved after taking famotidine. The pain had started while he was lying down after eating pizza, but it was worse and lasting longer than his usual heartburn.

    He had no nausea or shortness of breath, but he became sweaty and started coughing after the pain started. He had said it was hard to take a full breath. He was overweight, and could not remember when he had last seen a doctor. He reported that he did not smoke, and had no syncope, palpitations, chest pain, fever, or other symptoms.

    The patient's vital signs were normal, as was his exam. His ECG from triage about an hour after symptoms began is shown. (Image 1.) The computer read it as normal sinus rhythm, low voltage, borderline ECG. The ECG was repeated once he was in a room, which was about two hours after the heartburn started. (Image 2.) The computer reading was the same.

    What should you do next? Try Maalox or nitroglycerin, order a D-dimer in addition to the usual labs, or none of those?

    ECG Analysis

    The first ECG does show low voltage, likely due to body habitus because the pulse is low and he is not a smoker, making tamponade and COPD unlikely. A hint of ST depression is seen in leads 1, II, and aVL, and a subtle ST elevation may be present in V1-V2, but this could easily be a normal variant.

    Figure
    Figure:
    Image 2. The patient's second ECG taken about two hours after his heartburn started.

    The second ECG has dynamic changes with increased ST elevation in V1-V2 that the computer is not calling, but more impressive is the change in the shape and size of the T waves in V2-V6. These are hyperacute T-waves: the upslope has changed from concave to straight (this is the “bam” sign or “check mark” sign, according to Amal Mattu, MD). The overall volume of these T waves has increased, and they are quite large in relation to their QRS; you can even fit the entire QRS into the T-wave.

    Stephen W. Smith, MD, of Dr. Smith's ECG Blog, pointed out that even the first ECG, though not as concerning as the second, is perfect for applying the four-variable formula for differentiating normal ST elevation from subtle left anterior descending coronary artery occlusion myocardial infarction. The formula gives a value of 22.0, which is highly specific for LAD OMI. This could get the patient to the cath lab even sooner and lead to a better outcome. The formula is on MDcalc, and a free iPhone app called Subtle STEMI and a free Android app called ECG Smith can calculate the index.

    Maalox should only usually be tried once you are fairly confident it is not ACS; it may otherwise just mislead you. It wastes time in this case. You can certainly try nitroglycerin if the patient has no contraindications, but it is more important to activate the cath lab or at least send a deidentified copy of the ECG to the cardiologist. You should really not be doing anything that delays going to the cath lab, so don't order a D-dimer. Midsternal burning is unlikely to be a PE even if it is a bit pleuritic. A positive D-dimer can also lead you astray. Time is muscle here.

    The correct answer in this case is to do none of these. This patient's story and repeat ECG should prompt you to activate the cath lab or call cardiology as soon as possible. The man's troponin-i was less than 0.03 (99% URL <0.030: troponin-i immunoassay, Abbott Laboratories). A catheterization showed 99 percent occlusion of the LAD, 95 percent of the left circumflex, and 70 percent of the right coronary artery. A repeat troponin was 5.4.

    Case Lesson

    Patients with MI often say they have no pain and that it just feels like pressure, burning, or discomfort. Don't let them convince you their pain is noncardiac; only you should do that! Always do an early repeat ECG in patients with ongoing chest symptoms if the first ECG was performed within three hours of symptom onset.

    This post was peer-reviewed by Stephen W. Smith, MD, of Dr. Smith's ECG Blog (https://bit.ly/306xAeq).

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    Dr. Pregersonis an emergency physician with Palomar Health in San Diego. He is the author of Emergency Medicine 1-Minute Consult, the 8-in-1 Emergency Department Quick Reference Guide, the A to Z Emergency Pharmacopoeia & Antibiotic Guide, Don't Try This at Home, and Think Twice: More Lessons from the ER. Follow him on Twitter@EM1MinuteGuru, and visit his website athttps://em1minuteconsult.com. Read his past columns athttp://bit.ly/BradyCardiaEMN.

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