Wolff-Parkinson-White syndrome: could a normal PJ interval exclude bundle branch block?

Patients with a Wolff-Parkinson-White (WPW) pattern in the electrocardiogram (ECG) show a short PR interval (<120 ms), a wide QRS complex (>100 ms) with a delta wave, and a normal PJ interval. Broad QRS complexes may simulate bundle branch block (BBB). Furthermore, premature depolarization of ventricular myocardium through an accessory pathway tends to conceal any electrocardiographic manifestation of a BBB. WPW syndrome cannot prolong the PJ interval; therefore, PJ interval prolongation plays an important role in the differential diagnosis between BBB and WPW syndrome. However, could a normal PJ interval rule out BBB in the presence of WPW syndrome? A 28-year-old man with a 3-year history of frequent attacks of tachycardia was admitted to our hospital because of palpitations. The ECG revealed a sinus rhythm of approximately 60 beats/min, a PR interval of 0.10 s, and a QRS duration of 0.14 s (with a delta wave), with rS pattern in lead V1, suggestive of WPW syndrome type B (Fig. A). An ECG brought by the patient showed tachycardia of approximately 160 beats/min with broad QRS complexes of right bundle branch block (RBBB) morphology (Fig. B). The admission ECG demonstrated RBBB during the intermittency of preexcitation (Fig. C). Electrophysiological study and radiofrequency ablation (the accessory pathway [AP] located in tricuspid annulus 9:00) were performed. Postablation ECG showed RBBB with a PJ interval of 0.28 s (Fig. D). The PJ interval represents the time elapsed from the beginning of the P wave to the end of the QRS complex (J for junction between QRS and T wave) in the ECG. In addition, the PJ interval is equal to the sum of the PR interval (the time interval from the onset of atrial depolarization to the onset of ventricular depolarization) and the QRS interval (the total ventricular activation time), with a normal value of less than 0.27 s. A prolonged PJ interval is mainly observed in patients with first-degree atrioventricular block (AVB) or BBB. The diagnosis of first degree AVB is usually made on the basis of a Management of Hyperglycemia in Type 2 Diabetes: A Patient-Centered Ap proach: position statement of the American Diabetes Association (ADA) an the European Association for the Study of Diabetes (EASD). Diabetes Car 2012;35:1364–79. 4. Ali MK, Bullard KM, Saaddine JB, Cowie CC, Imperator G, Gregg EW. Achieve ment of Goals in U.S. Diabetes Care, 1999-2010. N Engl J Med. 2013;368 1613–24. 5. Navarro-Vidal B, Banegas JR, León-Muñoz LM, Rodrı́guez-Artalejo F, Graciani A Achievement of Cardiometabolic Goals among Diabetic Patients in Spain A Nationwide Population-Based Study. PLoS ONE. 2013;8:e61549. 6. Rodrı́guez-Artalejo F, Graciani A, Guallar-Castillón P, León-Muñoz LM Zuluaga MC, López-Garcı́a. et al. Justificación y métodos del estudio sobr nutrición y riesgo cardiovascular en España (ENRICA). Rev Esp Cardiol. 2011 64:876–82.