J-LSMS 2017 | Annual Archive

JOURNAL OF THE LOUISIANA STATE MEDICAL SOCIETY

DIAGNOSIS

The short PR interval (0.10 seconds), wide QRS complex (0.12 seconds), and delta waves (best seen in leads II, III, aVF, V1, V3-V6), are features of ventricular preexcitation of the Wolff-Parkinson- White type (WPW). 1 WPW is a notorious mimic of other conditions, especially myocardial infarct and left ventricular hypertrophy. WPW is best known for its association with supraventricular tachycardias which are usually initiated by an atrial premature complex, but canbe initiatedby ventricular premature complexes.Theensuing atrioventricular reciprocating tachycardia has a reentrant circuit usually characterized by so-called orthdromic conduction down the atrioventricular node, His bundle, and bundle branches, i.e., the normal conduction pathways, with conduction back to the atria via the accessory pathway, and the QRS complex is usually narrow unless the patient has a coexisting bundle branch block. 1 In a minority of cases, conduction is antidromic, i.e., down the accessory pathway with return to the atria retrogradely via the normal conduction system. Under these circumstances, the QRS complex is wide and not typical of block in either bundle branch. Not all patients withWPW-type ventricular preexcitation have tachyarrhythmias, 2 and thus far this patient has no history of same.

REFERENCES

1. Fisch C, Knoebel SB. Electrocardiography of Clinical Arrhythmias. Armonk, NY: Futura;2000:293-313. 2. Goudevenas JA, Katsouras CS, Graekas G, et al. Ventricular pre-excitation in the general population: a study of the mode of presentation and clinical course. Heart 2000;83:29-34.

Dr. Glancy is an emeritus professor of medicine (cardiology) at the Louisiana State University Health Sciences Center in New Orleans, LA.

84 J La State Med Soc VOL 169 MAY/JUNE 2017

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