Questioning Guidelines in the ECG Puzzler

Abstract

A recent ECG Puzzler article (“Nonsustained Ventricular Tachycardia in the Elderly,” September 2006: 519–520) contained several discrepencies with the current literature. They are as follows: (1) tachycardia was defined as a rate greater than 90/min, with normal defined as 60 to 90/min; (2) short PR interval was identified as less than 0.08 seconds; (3) wide QRS was identified as greater than 0.12 seconds; (4) nonsustained ventricular tachycardia (NSVT) was defined as 3 or more complexes at a rate greater than 120/min; and (5) I was simply unsure what point was being made about QRS complex direction.I have been teaching this content for 25 years and would define the above measurements as follows: (1) tachycardia is greater than 100/min; (2) normal PR interval is equal to or less than 0.11 seconds; (3) wide QRS complex duration is equal to or greater than 0.12 seconds; (4) NSVT rate is 3 or more complexes at a rate greater than 100/min (all tachycardia rhythms minimally fall under this definition); (5) as for ventricular tachycardia with positive QRS, in V1 the width greater than 0.14 seconds is a ventricular tachycardia characteristic; with a negative QRS in V1, the width equal to or greater than 0.16 is a characteristic of ventricular tachycardia.1There are so many more points to be made related to ECG characteristics of ventricular tachycardia that do not appear in this article, including but not limited to axis, capture and fusion complexes, previous ECG characteristics, and the 4 signs of ventricular tachycardia, which apply if QRS is greater than 0.14 seconds in V1 and/or V2. These 4 signs are (1) wide R (>0.04 seconds) in V1 and/or V2, (2) slurred S (notched) downstroke in V1 and/or V2, (3) delayed S nadir (>0.06 seconds) in V1 and/or V2, and (4) q wave in V6 when the complex is mainly negative in V1. Opposite polarity doesn’t always diagnose the rhythm as ventricular tachycardia.Also, it is troubling that the authors close the article with “it is important to rule out cardiac disease in this patient before he is discharged, by means of resting 12-lead ECG, serum biomarkers, echocardiography, and so on.” I find the phrase “and so on” a little disconcerting. This patient probably should receive serial ECGs (not just one), serial cardiac markers, risk assessment, and, at the very least, noninvasive testing including a stress test and perhaps a percutaneous coronary intervention.