LETTERS TO THE EDITOR Letter to Editor—Maneuvers in diagnosing permanent junctional reciprocating tachycardia Sternick et al1 reported a fascinating case of permanent junctional reciprocating tachycardia and postulated interesting anatomical explanations for the causative right-sided accessory pathway. We would like to point out the error in ventriculoatrial (VA) calculation used at the end of entrainment. To avoid confusion, this should be VAventricular pacing VAtachycardia as originally described by Michaud et al2 rather than the opposite stated. Although a cutoff of o85 ms would indicate a septal orthodromic accessory pathway reentrant tachycardia, this has not been validated in decremental pathways. A range of entrainment cycle lengths may have given further evidence of the decremental properties of the presumed pathway. A minor 10-ms decrement in His-synchronous ventricular premature beat prematurity produced a large delay in atrial timing. Conduction delay, albeit in a peripheral coronary sinus (CS) catheter, with His-synchronous ventricular premature beat and termination without an A may prove pathway participation in the tachycardia mechanism. One cannot ascertain whether this delay is attributed to intra-atrial conduction delay without catheters elsewhere in the right atrium and understanding the tissue conductive properties between atrial insertion point, tricuspid annulus, and CS catheter. Right ventricular catheter position relative to the “earliest” A was not indicated, given the distance to the ventricular insertion point can also influence VA times. The distal CS catheter positioned in the left ventricular branch of the CS in this case may have given the authors an opportunity to induce right bundle branch block morphology that will demonstrate prolongation of VA, adding evidence to the location of the pathway on the right heart. Wai Kah Choo, MBBS, MRCP, PGCMed, FHEA [email protected] Jonathan Affolter, MBBS, MD, MRCP, CCDS, CEPS Paul Broadhurst, MBBS, MD, FRCP, FESC, FHRS
Reply the Editor—A tachycardia using a decrementally conducting concealed accessory pathway between the superior caval vein-right atrial junction and the right ventricle We appreciate the comments made by Choo et al about our article.1 They are absolutely correct in pointing out that the original maneuver was VApacing VAtachycardia (VA¼ ventriculoatrial)2; however, the calculation using the reverse formulation would not change the final result—in this case 30 ms (there is no possibility of –30 ms). They also point out that the cutoff of o85 ms is not validated for decremental accessory pathways. We disagree with that statement because a value of o85 ms is certainly consistent with entrainment using an accessory pathway. What is considered a gray area is the finding the cutoff of 485 ms, which is not useful to distinguish between a decrementally conducting accessory pathway and atrial ventricular nodal conduction. In the article by Bennett et al,3 50% of patients with permanent junctional reciprocating tachycardia had Stimulus-A – VA (ventrículoatrial interval) o 85 ms. The large conduction delay associated with a “minor” 10ms decrement in a His-synchronous ventricular premature beat is explained by longitudinal dissociation of accessory pathway conduction. The author suggests the possibility of conduction delay in the atrium, but in a patient without structural heart disease this possibility is unlikely. Choo et al also pointed that the position of the right ventricular (RV) catheter was not mentioned, but it was clearly stated in Figure 3 that the RV catheter was positioned at the RV apex. Looking at the electrocardiogram during RV pacing, the finding of an inferior frontal plane QRS axis is consistent with a RV apical site of pacing, which is another way to check for the site of pacing. We also tried to do differential ventricular pacing (base vs apex),4 but as usual during permanent junctional reciprocating tachycardia the cycle length variability throughout the procedure is very high, making such a maneuver difficult to interpret.
Department of Cardiology, Aberdeen Royal Infirmary Aberdeen, United Kingdom
Eduardo Back Sternick, MD, PhD, FHRS*† [email protected] Yash Lokhandwala, MD, DM, FACC‡ Robert H. Anderson, BSc, MD, FRCPath§ Hein J.J. Wellens, MD, PhD, FACC#
References 1. Sternick EB, Lokhandwala Y, Anderson R, Wellens H. A tachycardia using a decrementally conducting concealed accessory pathway between the superior caval vein-right atrial junction and the right ventricle. Heart Rhythm 2015;12: 639–643. 2. Michaud GF, Tada H, Chough S, Baker R, Wasmer K, Sticherling C, Oral H, Pelosi F Jr, Knight BP, Strickberger SA, Morady F. Differentiation of atypical atrioventricular node re-entrant tachycardia from orthodromic reciprocating tachycardia using a septal accessory pathway by the response to ventricular pacing. J Am Coll Cardiol 2001;38:1163–1167.
1547-5271/$-see front matter B 2015 Heart Rhythm Society. All rights reserved.
*
Arrhythmia and Electrophysiology Unit, Biocor Instituto, Nova Lima, Brazil † Instituto de Pós-Graduação, Faculdade de Ciências Médicas de Minas Gerais, Belo Horizonte, Brazil ‡ Arrhythmia Associates, Mumbai, India http://dx.doi.org/10.1016/j.hrthm.2015.03.036
Reply the Editor—A tachycardia using a decrementally conducting concealed accessory pathway between the superior caval vein-right atrial junction and the right ventricle We appreciate the comments made by Choo et al about our article.1 They are absolutely correct in pointing out that the original maneuver was VApacing VAtachycardia (VA¼ ventriculoatrial)2; however, the calculation using the reverse formulation would not change the final result—in this case 30 ms (there is no possibility of –30 ms). They also point out that the cutoff of o85 ms is not validated for decremental accessory pathways. We disagree with that statement because a value of o85 ms is certainly consistent with entrainment using an accessory pathway. What is considered a gray area is the finding the cutoff of 485 ms, which is not useful to distinguish between a decrementally conducting accessory pathway and atrial ventricular nodal conduction. In the article by Bennett et al,3 50% of patients with permanent junctional reciprocating tachycardia had Stimulus-A – VA (ventrículoatrial interval) o 85 ms. The large conduction delay associated with a “minor” 10ms decrement in a His-synchronous ventricular premature beat is explained by longitudinal dissociation of accessory pathway conduction. The author suggests the possibility of conduction delay in the atrium, but in a patient without structural heart disease this possibility is unlikely. Choo et al also pointed that the position of the right ventricular (RV) catheter was not mentioned, but it was clearly stated in Figure 3 that the RV catheter was positioned at the RV apex. Looking at the electrocardiogram during RV pacing, the finding of an inferior frontal plane QRS axis is consistent with a RV apical site of pacing, which is another way to check for the site of pacing. We also tried to do differential ventricular pacing (base vs apex),4 but as usual during permanent junctional reciprocating tachycardia the cycle length variability throughout the procedure is very high, making such a maneuver difficult to interpret.
Department of Cardiology, Aberdeen Royal Infirmary Aberdeen, United Kingdom
Eduardo Back Sternick, MD, PhD, FHRS*† [email protected] Yash Lokhandwala, MD, DM, FACC‡ Robert H. Anderson, BSc, MD, FRCPath§ Hein J.J. Wellens, MD, PhD, FACC#
References 1. Sternick EB, Lokhandwala Y, Anderson R, Wellens H. A tachycardia using a decrementally conducting concealed accessory pathway between the superior caval vein-right atrial junction and the right ventricle. Heart Rhythm 2015;12: 639–643. 2. Michaud GF, Tada H, Chough S, Baker R, Wasmer K, Sticherling C, Oral H, Pelosi F Jr, Knight BP, Strickberger SA, Morady F. Differentiation of atypical atrioventricular node re-entrant tachycardia from orthodromic reciprocating tachycardia using a septal accessory pathway by the response to ventricular pacing. J Am Coll Cardiol 2001;38:1163–1167.
1547-5271/$-see front matter B 2015 Heart Rhythm Society. All rights reserved.
*
Arrhythmia and Electrophysiology Unit, Biocor Instituto, Nova Lima, Brazil † Instituto de Pós-Graduação, Faculdade de Ciências Médicas de Minas Gerais, Belo Horizonte, Brazil ‡ Arrhythmia Associates, Mumbai, India http://dx.doi.org/10.1016/j.hrthm.2015.03.036
