Differentiation of atypical atrioventricular node re-entrant tachycardia from orthodromic reciprocating tachycardia using a septal accessory pathway by the response to ventricular pacing
Gregory F. Michaud, MD, FACC*,
Hiroshi Tada, MD ,
Steven Chough, MD,
Robert Baker, MD,
Kristina Wasmer, MD,
Christian Sticherling, MD,
Hakan Oral, MD,
Frank Pelosi, Jr, MD,
Bradley P. Knight, MD, FACC,
S. Adam Strickberger, MD, FACC and
Fred Morady, MD, FACC
* Division of Cardiology, Department of Internal Medicine, Rhode Island Hospital, Brown University, Providence, Rhode Island, USA
University of Michigan Medical Center, Ann Arbor, Michigan, USA
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Figure 1 Entrainment of atrioventricular node re-entrant tachycardia (AVNRT) from the right ventricular septum (RVS) at a cycle length of 510 ms. (A) The ventriculo-atrial (VA) interval and tachycardia cycle length (TCL) are measured immediately before entrainment. (B) The stimulus-atrial (S-A) interval is measured from the last pacing stimulus to the last entrained high right atrial (HRA) electrogram, and the post-pacing interval (PPI) is measured from the last pacing stimulus to the return cycle RV electrogram. The S-A–VA interval is 120 ms, and the PPI–TCL is 150 ms. HBd = His bundle distal; S = stimulus.
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Figure 2 Entrainment of orthodromic reciprocating tachycardia (ORT) using a right posteroseptal bypass tract from the right ventricular apex (RVA) at a cycle length of 440 ms. (A) The ventriculo-atrial (VA) interval and tachycardia cycle length (TCL) are measured immediately before entrainment. (B) The stimulus-atrial (S-A) interval is measured from the last pacing stimulus to the last entrained high right atrial (HRA) electrogram, and the post-pacing interval (PPI) is measured from the last pacing stimulus to the return cycle RV electrogram. The S-A–VA interval is 40 ms, and the PPI–TCL is 80 ms. HBD = His bundle distal; S = stimulus.
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Figure 3 Scatterplot showing the mean value ± SD of the stimulus-atrial–ventriculo-atrial (S-A–VA) interval (ms) for patients with either orthodromic reciprocating tachycardia (ORT) using a septal accessory pathway or atypical atrioventricular node re-entrant tachycardia (AVNRT). The line drawn at 85 ms represents the discriminant point distinguishing the two forms of long VA tachycardia.
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Figure 4 Scatterplot showing the mean value ± SD of the post-pacing interval–tachycardia cycle length (PPI–TCL) (ms) for patients with either orthodromic reciprocating tachycardia (ORT) using a septal accessory pathway or atypical atrioventricular node re-entrant tachycardia (AVNRT). The line drawn at 115 ms represents the discriminant point distinguishing the two forms of long VA tachycardia.
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