Emergency in a Dilated Cardiomyopathy Patient

Philip J. Podrid, MD

Disclosures

June 18, 2020

The correct diagnosis is ventricular tachycardia (Figure 2).

Figure 2. Courtesy of Dr Podrid.

Discussion

The rhythm is regular at a rate of 130 beats/min. The QRS complex is wide (0.16 sec) and the axis is rightward (negative QRS complex in lead I and positive in lead aVF). Although there is a tall R wave in lead V1 (←), the QRS complex does not have a right bundle branch block morphology. In addition, there is evidence of intermittent P waves (+) that are not associated with the QRS complexes.

The presence of P waves associated with some but not all of the QRS complexes is consistent with atrioventricular (AV) dissociation. A wide-complex tachycardia with AV dissociation is ventricular tachycardia.

In the precordial leads V3-V4, the R wave is wider than the S wave and is > 100 msec. This is consistent with a ventricular complex. An RS complex in any precordial lead and an S wave that is wider than the R wave (and an R wave < 100 msec) is consistent with aberration. This is because with aberration it is the terminal portion of the QRS complex that is widened due to delayed activation of the ventricle served by the nonconducting bundle. Because the initial activation is normal, the R wave is narrow. With a ventricular complex, the R wave is wider than the S wave as even initial activation is abnormal. Therefore, this ECG has features characteristic of ventricular tachycardia.

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.

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