Acquired Long QT Syndrome

In recent years there has been considerable interest in the diagnosis and understanding of ventricular repolarisation, particularly the QT interval prolongation and abnormal T and T/U wave morphology associated with torsades de pointes. Advances in ion channel cloning have greatly improved our understanding of the role of ionic channels in mediating cardiac repolarisation. Unfortunately, it is increasingly recognised that a number of drugs, both those associated with altering repolarisation, and others for non-cardiac conditions can increase the propensity for polymorphic ventricular tachycardia, syncope and even ventricular fibrillation and sudden death. In this volume, arrhythmia specialists from St. George s Hospital Medical School, London discuss the mechanisms behind QT prolongation and torsades de pointes. They focus particularly on the risk of individual cardiac and non-cardiac drugs in provoking long QT syndrome, providing a comprehensive review which will be useful for all electrophysiologists treating polymorphic ventricular tachycardias, and will expose important regulatory issues for pharmaceutical authorities and for the wider medical community.

In recent years there has been considerable interest in thediagnosis and understanding of ventricular repolarisationparticularly the QT interval prolongation and abnormal T and T/Uwave morphology associated with torsades de pointes. Advances inion channel cloning have greatly improved our understanding of therole of ionic channels in mediating cardiac repolarisation.Unfortunately, it is increasingly recognised that a number ofdrugs, both those associated with altering repolarisation, andothers for non-cardiac conditions can increase the propensity forpolymorphic ventricular tachycardia, syncope and even ventricularfibrillation and sudden death.In this volume, arrhythmia specialists from St. George'sHospital Medical School, London discuss the mechanisms behind QTprolongation and torsades de pointes. They focus particularly onthe risk of individual cardiac and non-cardiac drugs in provokinglong QT syndrome, providing a comprehensive review which will beuseful for all electrophysiologists treating polymorphicventricular tachycardias, and will expose important regulatoryissues for pharmaceutical authorities and for the wider medicalcommunity.

Preface vi1 Introduction 12 Mechanisms of acquired QT prolongation and torsades de pointes 83 Measurement of the QT interval and repolarization assessment 244 Introduction to drug-induced long QT syndrome 605 Risk of QT prolongation and torsades de pointes with antiarrhythmic drugs 696 Risk of QT prolongation and torsades de pointes with antihistamines 877 Risk of QT prolongation and torsades de pointes with psychotropic drugs 1028 Risk of QT prolongation and torsades de pointes with antimicrobial and antimalarial drugs 1219 Risk of QT prolongation and torsades de pointes with prokinetics and miscellaneous other drugs 14010 Acquired long QT syndrome secondary to cardiac conditions 16311 Acquired long QT syndrome secondary to noncardiac conditions 17112 Perspective on drug-induced repolarization changes 182Index 191