Intra-atrial conduction block along the mitral valve annulus during accessory pathway ablation: Evidence for a left atrial "Isthmus"

David M. Luria, Jan Nemec, Susan P. Etheridge, Steven J. Compton, Richard C. Klein, Sumeet S. Chugh, Thomas M. Munger, Win K. Shen, Douglas L Packer, Arshad Jahangir, Robert F. Rea, Stephen C. Hammill, Paul Andrew Friedman

Research output: Contribution to journalArticle

43 Citations (Scopus)

Abstract

Introduction: We observed a change in the atrial activation sequence during radiofrequency (RF) energy application in patients undergoing left accessory pathway (AP) ablation. This occurred without damage to the AP and in the absence of a second AP or alternative arrhythmia mechanism. We hypothesized that block in a left atrial "isthmus" of tissue between the mitral annulus and a left inferior pulmonary vein was responsible for these findings. Methods and Results: Electrophysiologic studies of 159 patients who underwent RF ablation of a left free-wall AP from 1995 to 1999 were reviewed. All studies with intra-atrial conduction block resulting from RF energy delivery were identified. Fluoroscopic catheter positions were reviewed. Intra-atrial conduction block was observed following RF delivery in 11 cases (6.9%). This was evidenced by a sudden change in retrograde left atrial activation sequence despite persistent and unaffected pathway conduction. In six patients. reversal of eccentric atrial excitation during orthodromic reciprocating tachycardia falsely suggested the presence of a second (septal) AP. A multipolar coronary sinus catheter in two patients directly demonstrated conduction block along the mitral annulus during tachycardia. Conclusion: An isthmus of conductive tissue is present in the low lateral left atrium of some individuals. Awareness of this structure may avoid misinterpretation of the electrogram during left AP ablation and may be useful in future therapies of atypical atrial flutter and fibrillation.

Original languageEnglish (US)
Pages (from-to)744-749
Number of pages6
JournalJournal of Cardiovascular Electrophysiology
Volume12
Issue number7
StatePublished - 2001

Fingerprint

Mitral Valve
Catheters
Reciprocating Tachycardia
Atrial Flutter
Coronary Sinus
Pulmonary Veins
Heart Atria
Tachycardia
Atrial Fibrillation
Cardiac Arrhythmias
Therapeutics

Keywords

  • Accessory pathway
  • Conduction
  • Left atrium
  • Radiofrequency ablation

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Physiology

Cite this

Intra-atrial conduction block along the mitral valve annulus during accessory pathway ablation : Evidence for a left atrial "Isthmus". / Luria, David M.; Nemec, Jan; Etheridge, Susan P.; Compton, Steven J.; Klein, Richard C.; Chugh, Sumeet S.; Munger, Thomas M.; Shen, Win K.; Packer, Douglas L; Jahangir, Arshad; Rea, Robert F.; Hammill, Stephen C.; Friedman, Paul Andrew.

In: Journal of Cardiovascular Electrophysiology, Vol. 12, No. 7, 2001, p. 744-749.

Research output: Contribution to journalArticle

Luria, DM, Nemec, J, Etheridge, SP, Compton, SJ, Klein, RC, Chugh, SS, Munger, TM, Shen, WK, Packer, DL, Jahangir, A, Rea, RF, Hammill, SC & Friedman, PA 2001, 'Intra-atrial conduction block along the mitral valve annulus during accessory pathway ablation: Evidence for a left atrial "Isthmus"', Journal of Cardiovascular Electrophysiology, vol. 12, no. 7, pp. 744-749.
Luria, David M. ; Nemec, Jan ; Etheridge, Susan P. ; Compton, Steven J. ; Klein, Richard C. ; Chugh, Sumeet S. ; Munger, Thomas M. ; Shen, Win K. ; Packer, Douglas L ; Jahangir, Arshad ; Rea, Robert F. ; Hammill, Stephen C. ; Friedman, Paul Andrew. / Intra-atrial conduction block along the mitral valve annulus during accessory pathway ablation : Evidence for a left atrial "Isthmus". In: Journal of Cardiovascular Electrophysiology. 2001 ; Vol. 12, No. 7. pp. 744-749.
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T2 - Evidence for a left atrial "Isthmus"

AU - Luria, David M.

AU - Nemec, Jan

AU - Etheridge, Susan P.

AU - Compton, Steven J.

AU - Klein, Richard C.

AU - Chugh, Sumeet S.

AU - Munger, Thomas M.

AU - Shen, Win K.

AU - Packer, Douglas L

AU - Jahangir, Arshad

AU - Rea, Robert F.

AU - Hammill, Stephen C.

AU - Friedman, Paul Andrew

PY - 2001

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N2 - Introduction: We observed a change in the atrial activation sequence during radiofrequency (RF) energy application in patients undergoing left accessory pathway (AP) ablation. This occurred without damage to the AP and in the absence of a second AP or alternative arrhythmia mechanism. We hypothesized that block in a left atrial "isthmus" of tissue between the mitral annulus and a left inferior pulmonary vein was responsible for these findings. Methods and Results: Electrophysiologic studies of 159 patients who underwent RF ablation of a left free-wall AP from 1995 to 1999 were reviewed. All studies with intra-atrial conduction block resulting from RF energy delivery were identified. Fluoroscopic catheter positions were reviewed. Intra-atrial conduction block was observed following RF delivery in 11 cases (6.9%). This was evidenced by a sudden change in retrograde left atrial activation sequence despite persistent and unaffected pathway conduction. In six patients. reversal of eccentric atrial excitation during orthodromic reciprocating tachycardia falsely suggested the presence of a second (septal) AP. A multipolar coronary sinus catheter in two patients directly demonstrated conduction block along the mitral annulus during tachycardia. Conclusion: An isthmus of conductive tissue is present in the low lateral left atrium of some individuals. Awareness of this structure may avoid misinterpretation of the electrogram during left AP ablation and may be useful in future therapies of atypical atrial flutter and fibrillation.

AB - Introduction: We observed a change in the atrial activation sequence during radiofrequency (RF) energy application in patients undergoing left accessory pathway (AP) ablation. This occurred without damage to the AP and in the absence of a second AP or alternative arrhythmia mechanism. We hypothesized that block in a left atrial "isthmus" of tissue between the mitral annulus and a left inferior pulmonary vein was responsible for these findings. Methods and Results: Electrophysiologic studies of 159 patients who underwent RF ablation of a left free-wall AP from 1995 to 1999 were reviewed. All studies with intra-atrial conduction block resulting from RF energy delivery were identified. Fluoroscopic catheter positions were reviewed. Intra-atrial conduction block was observed following RF delivery in 11 cases (6.9%). This was evidenced by a sudden change in retrograde left atrial activation sequence despite persistent and unaffected pathway conduction. In six patients. reversal of eccentric atrial excitation during orthodromic reciprocating tachycardia falsely suggested the presence of a second (septal) AP. A multipolar coronary sinus catheter in two patients directly demonstrated conduction block along the mitral annulus during tachycardia. Conclusion: An isthmus of conductive tissue is present in the low lateral left atrium of some individuals. Awareness of this structure may avoid misinterpretation of the electrogram during left AP ablation and may be useful in future therapies of atypical atrial flutter and fibrillation.

KW - Accessory pathway

KW - Conduction

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KW - Radiofrequency ablation

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