ECG Challenge: Did COPD Cause This Man's Irregular Heart Rate?

The correct diagnosis is wandering atrial pacemaker/multifocal atrial rhythm (Figure 2).

Figure 2. Courtesy of Dr Podrid.

Discussion

The rhythm is irregularly irregular at a rate of 90 beats/min. The QRS complexes are narrow with a normal axis, and there is voltage criterion for left ventricular hypertrophy LVH (]) — QRS complex amplitude in any precordial lead ≥ 25 mm — with associated ST-T wave abnormalities (^).

Only three supraventricular rhythms are irregularly irregular:

• Sinus arrhythmia (one P-wave morphology and stable PR interval) which is a normal respirophasic arrhythmia

• Atrial fibrillation (no organized P wave but fibrillatory waves)

• Multifocal atrial rhythm or wandering atrial pacemaker (rate < 100 beats/min) or multifocal atrial tachycardia (rate > 100 beats/min)

With these arrhythmias there are at least three different P-wave morphologies, and no P-wave morphology is dominant. PR intervals are also variable. As seen, there are P waves before each QRS complex (+) with at least six different P-wave morphologies. The PP intervals and hence QRS intervals are irregularly irregular. Occasional P waves are nonconducted (*). Multifocal atrial rhythm and multifocal atrial tachycardia are very often associated with severe lung disease.

Philip Podrid, MD, is an electrophysiologist, a professor of medicine and pharmacology at Boston University School of Medicine, and a lecturer in medicine at Harvard Medical School. Although retired from clinical practice, he continues to teach clinical cardiology and especially ECGs to medical students, house staff, and cardiology fellows at many major teaching hospitals in Massachusetts. In his limited free time he enjoys photography, music, and reading.

You can follow Dr Podrid on Twitter @PPodrid

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Cite this: ECG Challenge: Did COPD Cause This Man's Irregular Heart Rate? - Medscape - Jan 25, 2021.