Ventricular tachycardia with regular capture beats.

To cite: Mahla H, Shenthar J, Sunil Kumar KR, et al. BMJ Case Rep Published online: [please include Day Month Year] doi:10.1136/bcr-2014204121 DESCRIPTION A 30-year-old man presented with a 1-day history of sudden onset palpitations. He was haemodynamically stable. Twelve-lead electrocardiography showed wide complex tachycardia with right bundle branch block and left superior axis (figures 1 and 2). Every two wide complex beats were followed by a narrow complex beat and this cycle was repeating. Careful inspection revealed that narrow complex beats were having fixed relationship to wide complexes and among themselves, but there was atrioventricular (AV) dissociation. The patient’s echocardiographic examination was normal. He was reverted to normal sinus rhythm with DC cardio V.150 Joules. Before direct current (DC) cardioversion, verapamil and β-blockers tried but not successful. These narrow complexes were capture beats 2 as they were same as sinus beats (in having a qR in V1) when the patient was in sinus rhythm after treatment (figure 3). Ventricular tachycardia (VT) localisation was idiopathic left ventricular VT from posterior fascicle, but regularity of capture beats was the one point that made us doubt our diagnosis. The only explanation we can offer is that patient might be having dual AV node physiology or re-entry occurring at junction. The narrow complex beat may be conducting via the one pathway (interval between preceding wide QRS beat and narrow QRS beat is shorter than the interval between narrow QRS and following wide QRS beat best seen in V1) but at the same time the other site of the circuit is refractory, so re-entry abolishes and V happens with wide QRS. Again after two V’s this cycle reappears. Response to DC shock