November 28, 2024

55-year-old man with a history of COPD and hypertension

By Med-Challenger · 2 minute read

A 55-year-old man with a history of chronic obstructive pulmonary disease (COPD) and hypertension, comes in with acute dyspnea, and has run out of his medications. He complains of palpitations for less than 24 hours.

His vital signs are BP, 140/85; P, 105; RR, 20; T, 98.6 F; pulse oximetry is 92% on room air. His exam is remarkable for a rapid heart rate of uncertain rhythm, and his lung exam shows decreased air movement. His lab work includes a calcium 8.9 mg/dL; magnesium 2 mg/dL; potassium 3.8 meq/L (click here for reference lab values); ECG shows variable rate around 105; p waves of varying morphology; variable P-P, PR, and R-R intervals (see below ECG).

image (28)

What is the most appropriate treatment for this particular patient, given these ECG findings?

Magnesium IV
Synchronized cardioversion
Nebulized beta-agonists
100%FiO2 via non-rebreather mask
Diltiazem

The correct answer is:

Nebulized beta-agonists

The patient’s ECG indicates multifocal atrial tachycardia (MAT), anatrial dysrhythmia seen with COPD. MAT usually resolves with treatment of the underlying condition, namely the COPD. Nebulized beta-agonists, such as albuterol, are first-line treatments for COPD, even in the presence of MAT. The heart rate of 105 does not preclude giving beta-agonists.

Electrolyte abnormalities are also common causes of MAT and should be treated. Magnesium IV may be used to treat suspected hypomagnesemia, a common cause of MAT. However, the patient’s calcium, magnesium, and potassium levels are normal.

Low levels of supplemental O2 at 2-3 L/min by nasal cannula are more appropriate. 100% FiO2 would likely depress the COPD patient’s hypoxic drive to breathe (FiO2 of 100% may be appropriate in the context of intubation, which was not the above scenario).

Diltiazem may be used to treat persistent MAT, after addressing the underlying cause. Atrial fibrillation is also a common dysrhythmia seen in COPD and is often confused with MAT; however this patient does not have atrial fibrillation (the above ECG has P-waves). Atrial fibrillation has no identifiable p wave morphology. Synchronized cardioversion may be appropriate if this patient exhibited clinical instability unresponsive to initial COPD treatment.

References:

Marx: Rosen's Emergency Medicine, 8th ed.: Saunders; 2014. CHAPTER 74 – Chronic Obstructive Pulmonary Disease

Marx: Rosen's Emergency Medicine, 8th ed.: Saunders; 2014. CHAPTER 79 – Dysrhythmias

This question appears in Med-Challenger Emergency Medicine Review with CME

Try for free and save. Ace your exams and meet your CME/MOC requirements for just $35 a month!

No matter your program, no matter the size, Med-Challenger for Groups and Institutions can better prepare your program or group, fulfill industry requirements, and increase test scores.