Episodes of recurrent palpitations and EKG findings revealing a pre-excitation are consistent with a diagnosis of Wolff-Parkinson-White Syndrome (WPW), an atrioventricular reciprocating tachycardia.
WPW is a supraventricular tachycardia resulting from pre-excitation of the ventricle due to accelerated conduction along an accessory atrioventricular (AV) pathway that bypasses the AV node. This is considered an atrioventricular reciprocating tachycardia (AVRT). AVRTs make up 30% of supraventricular tachycardias, while atrioventricular nodal reentrant tachycardias (AVNRT) make up 60%.
Colucci et al. describe the diagnosis and management of supraventricular tachycardias. They note that patients with AVRT typically present at a younger age than those with AVNRT. WPW is a diagnosis not to be missed because this rhythm may spontaneously develop into atrial fibrillation.
Plumb reports on catheter ablation as a method of treating WPW. He notes that in all forms of symptomatic WPW, catheter ablation with radiofrequency current of the accessory atrioventricular connections has become the treatment of choice.
Image A is an EKG displaying the classic findings of WPW: a wide QRS (> 0.12 second) with initial slurring (delta wave), sinus rhythm, and a short PR (< 0.12 second).
Illustration A shows the delta wave in WPW.
Incorrect Answer Explanations:
Answer 1: Atrial fibrillation can be a complication of WPW, but the patient's EKG shows sinus rhythm and features of WPW.
Answer 2: Panic attacks may present as intermittent episodes of palpitations and shortness of breath. Usually, the physical symptoms are preceded by feelings of anxiety or fear.
Answer 3: Ventricular tachycardias are very dangerous rhythms that originate in the ventricles. To diagnose VT on EKG one must see atrial-ventricular dissociation. This is not consistent with the EKG provided for this patient.
Answer 5: A Mobitz Type II AV block would present with a normal PR interval, but with occasional dropped beats. This means that you would see normal P-QRS waves and then on occasion you would see a P-wave without an associated QRS. Contrast this to Mobitz Type I which demonstrates consistent P-QRS lengthening.
Colucci RA, Silver MJ, Shubrook J. Common types of supraventricular tachycardia: diagnosis and management. Am Fam Physician. 2010 Oct 15;82(8):942-52. Review. PubMed PMID: 20949888.
PMID:20949888 (Link to Abstract)
Plumb VJ. Catheter ablation of the accessory pathways of the Wolff-Parkinson-White syndrome and its variants. Prog Cardiovasc Dis. 1995 Mar-Apr;37(5):295-306. Review. PubMed PMID: 7871178.
PMID:7871178 (Link to Abstract)