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Basic Research in Cardiology

, Volume 100, Issue 4, pp 365–371 | Cite as

Verapamil prevents torsade de pointes by reduction of transmural dispersion of repolarization and suppression of early afterdepolarizations in an intact heart model of LQT3

  • P. MilbergEmail author
  • N. Reinsch
  • N. Osada
  • K. Wasmer
  • G. Mönnig
  • J. Stypmann
  • G. Breithardt
  • W. Haverkamp
  • L. Eckardt
ORIGINAL CONTRIBUTION

Abstract

Background

In long QT syndrome (LQTS), prolongation of the QT–interval is associated with sudden cardiac death resulting from potentially life–threatening polymorphic tachycardia of the torsade de pointes (TdP) type. Experimental as well as clinical reports support the hypothesis that calcium channel blockers such as verapamil may be an appropriate therapeutic approach in LQTS. We investigated the electrophysiologic mechanism by which verapamil suppresses TdP, in a recently developed intact heart model of LQT3.

Methods and results

In 8 Langendorff–perfused rabbit hearts, veratridine (0.1 µM), an inhibitor of sodium channel inactivation, led to a marked increase in QT–interval and simultaneously recorded monophasic ventricular action potentials (MAPs) (p < 0.05) thereby mimicking LQT3. In bradycardic (AV–blocked) hearts, simultaneous recording of up to eight epi– and endocardial MAPs demonstrated a significant increase in total dispersion of repolarization (56%, p < 0.05) and reverse frequency–dependence. After lowering potassium concentration, veratridine reproducibly led to early afterdepolarizations (EADs) and TdP in 6 of 8 (75%) hearts. Additional infusion of verapamil (0.75 µM) suppressed EADs and consecutively TdP in all hearts. Verapamil significantly shortened endocardial but not epicardial MAPs which resulted in significant reduction of ventricular transmural dispersion of repolarization.

Conclusions

Verapamil is highly effective in preventing TdP via shortening of endocardial MAPs, reduction of left ventricular transmural dispersion of repolarization and suppression of EADs in an intact heart model of LQT3. These data suggest a possible therapeutic role of verapamil in the treatment of LQT3 patients.

Key words

Torsade de pointes verapamil long QT syndrome early afterdepolarizations transmural dispersion 

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Copyright information

© Steinkopff Verlag 2005

Authors and Affiliations

  • P. Milberg
    • 1
    Email author
  • N. Reinsch
    • 1
  • N. Osada
    • 2
  • K. Wasmer
    • 1
  • G. Mönnig
    • 1
  • J. Stypmann
    • 1
  • G. Breithardt
    • 1
  • W. Haverkamp
    • 1
    • 3
  • L. Eckardt
    • 1
  1. 1.Medizinische Klinik und Poliklinik C, Kardiologie und Angiologie Universitätsklinikum MünsterMünsterGermany
  2. 2.Department of Medical Informatics and BiomathematicsUniversity of MünsterMünsterGermany
  3. 3.Department of CardiologyCampus Virchow Clinic, Charité—University Medicine BerlinBerlinGermany

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