We thank Trebach et al. for their thoughtful comments and agree with their opinion. They said that supratherapeutic ingestion of propafenone followed by a very wide QRS complex tachycardia (WCT) with aberrantly conducted supraventricular tachycardia (SVT). The correct diagnosis in WCT is generally difficult to elucidate. When WCT is terminated by verapamil in this patient, a 12-lead electrocardiography (ECG) showed normal QRS duration and axis. Thus, WCT could be interpreted as ventricular tachycardia (VT) or aberrantly conducted SVT resulting from the effect of antiarrhythmic drugs, which slow down intraventricular conduction. However, as we mention in our article, the 12-lead ECG showed regular wide complex tachycardia with a right bundle branch block configuration, RSR’ complex with a taller left rabbit ear sign, rS complex in V5-V6, R in aVR, and right superior axis, which favoring ventricular tachycardia.1,2 However, the specificity of the described morphological ECG VT criteria could be low in patients with conduction disturbances,3 electrophysiology study was performed for differential diagnosis. Neither VT nor SVT was triggered from programmed electrical stimulation; therefore, the accurate diagnosis seems to be in a labyrinth. Thus, it would be nice to change the title like this, "Wide QRS complex tachycardia in association with propafenone overdose."
CONFLICT OF INTEREST
All the authors declare no conflict of interest.
REFERENCES
- 1.Brugada P, Brugada J, Mont L, et al. A new approach to the differential diagnosis of a regular tachycardia with a wide QRS complex. Circulation. 1991;83:1649–1659. doi: 10.1161/01.cir.83.5.1649. [DOI] [PubMed] [Google Scholar]
- 2.Vereckei A, Duray G, Szénási G, et al. New algorithm using only lead aVR for differential diagnosis of wide QRS complex tachycardia. Heart Rhythm. 2008;5:89–98. doi: 10.1016/j.hrthm.2007.09.020. [DOI] [PubMed] [Google Scholar]
- 3.Datino T, Almendral J, Avila P, et al. Specificity of electrocardiographic criteria for the differential diagnosis of wide QRS complex tachycardia in patients with intraventricular conduction defect. Heart Rhythm. 2013;10:1393–1401. doi: 10.1016/j.hrthm.2013.07.006. [DOI] [PubMed] [Google Scholar]