Two-to-One AV Block Associated with the Congenital Long QT Syndrome |
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Authors: | ETIENNE PRUVOT,M.D.,ANTOINE De, TORRENTE,M.D.&dagger ,GAETANO M. De, FERRARI,M.D.&Dagger ,PETER J. SCHWARTZ M.D.,FACC,FESC.,&Dagger JEAN-JACQUES GOY,M.D.,FESC |
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Affiliation: | Division of Cardiology, University Hospital, Lausanne;Hospital de la Chaux-de-Fonds, La Chaux-de-Fonds, Switzerland;Universita degli Studi di Pavia, Pavia, Italy |
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Abstract: | 2:1 AV Block in LQTS. Introduction Conduction abnormalities associated with long QT syndrome (LQTS) have been reported as "pseudo 2:1 AV block" due to sinus intervals shorter than ventricular refractoriness. Method and Results: We report the electrophysiologic characteristics of a patient suffering from congenital LQTS with episodes of true 2:1 AV block. Induction of 2:1 infra-Hisian blocks and return to 1:1 conduction were observed using single atrial and ventricular extrastimuli. The block was located in the Purkinje network but not in the myocardium. Conclusion: The His-Purkinje system of our LQTS patient displayed dynamic properties with a strong increase in refractoriness for short-long sequences and a decrease for long-short sequences that triggered intermittent 2:1 AV blocks. |
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Keywords: | LQTS His-Pirkinje system AV block refractory period left cardiac sympathetic denervation electrophysiologic study |
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