PMID- 12380931 OWN - NLM STAT- MEDLINE DCOM- 20030212 LR - 20220316 IS - 1045-3873 (Print) IS - 1045-3873 (Linking) VI - 13 IP - 9 DP - 2002 Sep TI - Restitution properties and occurrence of ventricular arrhythmia in LQT2 type of long QT syndrome. PG - 910-4 AB - INTRODUCTION: The aim of this study was to clarify the ventricular tachyarrhythmia mechanism induced by the I(Kr)-blocking agent E4031, simulating the LQT2 form. Electrophysiologic properties were examined in 13 canines before and after administration of E4031. METHOD AND RESULTS: Thirty-six needle electrodes were inserted into the anterior left ventricular wall. From each needle, local unipolar electrograms were obtained from four intramural sites. Activation time (AT) and activation-recovery interval (ARI) were measured. To evaluate the susceptibility to ventricular arrhythmia, intramural ARI dispersions and the restitution relationship between ARI and diastolic interval were calculated. After E4031 administration, ARI prolonged uniformly in each myocardial layer. However, ARI dispersion was not augmented compared with control. The slope of the ARI restitution curve after E4031 was significantly steeper than control. A steep slope may result from augmented ARI alternans. In 11 of the 13 canines, ventricular tachyarrhythmia was induced by programmed stimulation after E4031, whereas no arrhythmia was induced by the same protocol in control. CONCLUSION: Steepness of electrical restitution may play a major role in arrhythmogenicity in LQT2 hearts. FAU - Yamauchi, Sou AU - Yamauchi S AD - First Department of Internal Medicine, Yamagata University School of Medicine, Japan. FAU - Yamaki, Michiyasu AU - Yamaki M FAU - Watanabe, Tetsu AU - Watanabe T FAU - Yuuki, Kouichi AU - Yuuki K FAU - Kubota, Isao AU - Kubota I FAU - Tomoike, Hitonobu AU - Tomoike H LA - eng PT - Comparative Study PT - Evaluation Study PT - Journal Article PT - Research Support, Non-U.S. Gov't PL - United States TA - J Cardiovasc Electrophysiol JT - Journal of cardiovascular electrophysiology JID - 9010756 RN - 0 (Anti-Arrhythmia Agents) RN - 0 (Piperidines) RN - 0 (Pyridines) RN - 113558-89-7 (E 4031) SB - IM CIN - J Cardiovasc Electrophysiol. 2002 Sep;13(9):915-7. PMID: 12380932 CIN - J Cardiovasc Electrophysiol. 2003 Jan;14(1):114; author reply 114-5. PMID: 12625624 MH - Animals MH - Anti-Arrhythmia Agents/administration & dosage MH - Cardiac Pacing, Artificial MH - Disease Models, Animal MH - Disease Susceptibility MH - Dogs MH - *Electrocardiography MH - Electrophysiologic Techniques, Cardiac MH - Heart Conduction System/drug effects/pathology MH - Heart Ventricles/drug effects/pathology MH - Long QT Syndrome/complications/*diagnosis/therapy MH - Models, Cardiovascular MH - Piperidines/administration & dosage MH - Pyridines/administration & dosage MH - Tachycardia, Ventricular/diagnosis/*epidemiology/therapy EDAT- 2002/10/17 04:00 MHDA- 2003/02/14 04:00 CRDT- 2002/10/17 04:00 PHST- 2002/10/17 04:00 [pubmed] PHST- 2003/02/14 04:00 [medline] PHST- 2002/10/17 04:00 [entrez] AID - 10.1046/j.1540-8167.2002.00910.x [doi] PST - ppublish SO - J Cardiovasc Electrophysiol. 2002 Sep;13(9):910-4. doi: 10.1046/j.1540-8167.2002.00910.x.