Rosh Emergency Medicine Practice Test

What is the rhythm seen on the electrocardiogram of a patient with COPD presenting with tachycardia?

1. Atrial fibrillation

2. Multifocal atrial tachycardia

3. Sinus tachycardia with premature ventricular beats

4. Wandering atrial pacemaker

The correct answer is: Multifocal atrial tachycardia

Multifocal atrial tachycardia is characterized by the presence of three or more distinct P-wave morphologies, which result from ectopic foci in the atria firing at different rates. In patients with chronic obstructive pulmonary disease (COPD), this rhythm is a common finding due to the increased atrial irritability that can occur in response to factors such as hypoxia, acidosis, or increased sympathetic tone. The acute respiratory distress and resultant hypoxia experienced by COPD patients can further enhance the likelihood of atrial ectopy. Multifocal atrial tachycardia typically presents with a heart rate that is usually between 100 to 150 beats per minute, aligning with the tachycardic presentation and underlying pulmonary pathology. In contrast, while atrial fibrillation features irregularly spaced R-R intervals and an absence of discernible P waves, it might not be directly linked to the COPD patient population in the same way that multifocal atrial tachycardia is. Sinus tachycardia with premature ventricular beats would present with a consistent P-wave morphology and could indicate secondary issues due to stress or hypoxia but is less specific. Wandering atrial pacemaker would show variations in atrial pacing but usually occurs