Effect of Short-term Cardiac Memory on Ventricular Electrical Restitution and QT Intervals in Humans

Cardiac memory (CM) can alter the configuration of action potentials and the transmural repolarization gradient in ventricular tissue. This study evaluated the effects of CM on ventricular arrhythmogenicity. A total of 20 patients (12 females, 8 males; mean age, 46 ± 13 years) were enrolled. The fol...

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Main Authors: Kun-Tai Lee, Chih-Sheng Chu, Kai-Hung Cheng, Ye-Hsu Lu, Chih-Hsin Huang, Tsung-Hsien Lin, Ming-Chuan Lee, Sheng-Hsiung Sheu, Wen-Ter Lai
Format: Article
Language:English
Published: Wiley 2009-02-01
Series:Kaohsiung Journal of Medical Sciences
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S1607551X09700415
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spelling doaj-9be89fba89a445d9b87294a00f0831532020-11-25T01:18:05ZengWileyKaohsiung Journal of Medical Sciences1607-551X2009-02-01252536110.1016/S1607-551X(09)70041-5Effect of Short-term Cardiac Memory on Ventricular Electrical Restitution and QT Intervals in HumansKun-Tai Lee0Chih-Sheng Chu1Kai-Hung Cheng2Ye-Hsu Lu3Chih-Hsin Huang4Tsung-Hsien Lin5Ming-Chuan Lee6Sheng-Hsiung Sheu7Wen-Ter Lai8Department of Internal Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, TaiwanDepartment of Internal Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, TaiwanDivision of Cardiology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung, TaiwanDivision of Cardiology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung, TaiwanDivision of Cardiology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung, TaiwanDepartment of Internal Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, TaiwanDivision of Cardiology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung, TaiwanDepartment of Internal Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, TaiwanDepartment of Internal Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, TaiwanCardiac memory (CM) can alter the configuration of action potentials and the transmural repolarization gradient in ventricular tissue. This study evaluated the effects of CM on ventricular arrhythmogenicity. A total of 20 patients (12 females, 8 males; mean age, 46 ± 13 years) were enrolled. The following indicators were measured to evaluate ventricular arrhythmogenicity: (1) the action potential duration at 90% repolarization (APD 90) recorded from the right ventricular apex (RVA); (2) the maximal slope of the action potential duration restitution curve (APDR) constructed by programmed extra stimuli from RVA; and (3) the maximal corrected QT interval (QTc) and QT interval dispersion (QTd). The short-term CM was induced by constant pacing from the RVA at a pacing cycle length (PCL) of 400 ms for 20 minutes. After induction of CM, the mean APD 90 were significantly shortened at both PCLs of 600 ms and 400 ms (252.9 ± 6.4 ms vs. 235.6 ± 6.4 ms and 231.2 ± 6.4 ms vs. 214.4 ± 7.3 ms, respectively; p = 0.001). No significant change regarding the maximal slopes of APDR were found at both PCLs of 600 ms and 400 ms (1.05 ± 0.09 vs. 0.96 ± 0.11 and 0.85 ± 0.08 vs. 0.84 ± 0.09, respectively). QTc (417.3 ± 9.1 ms vs. 454.7 ± 8.3 ms; p = 0.001), but not QTd (63.4 ± 5.4 ms vs. 65.7 ± 6.1 ms), was significantly shortened. Short-term CM significantly decreased ventricular APD 90 and QTc, but did not significantly change the maximal slope of APDR or QTd. These results suggest that CM might not have a significant effect on ventricular arrhythmogenicity.http://www.sciencedirect.com/science/article/pii/S1607551X09700415cardiac memoryQT intervalventricular arrhythmiasventricular electrical restitution
collection DOAJ
language English
format Article
sources DOAJ
author Kun-Tai Lee
Chih-Sheng Chu
Kai-Hung Cheng
Ye-Hsu Lu
Chih-Hsin Huang
Tsung-Hsien Lin
Ming-Chuan Lee
Sheng-Hsiung Sheu
Wen-Ter Lai
spellingShingle Kun-Tai Lee
Chih-Sheng Chu
Kai-Hung Cheng
Ye-Hsu Lu
Chih-Hsin Huang
Tsung-Hsien Lin
Ming-Chuan Lee
Sheng-Hsiung Sheu
Wen-Ter Lai
Effect of Short-term Cardiac Memory on Ventricular Electrical Restitution and QT Intervals in Humans
Kaohsiung Journal of Medical Sciences
cardiac memory
QT interval
ventricular arrhythmias
ventricular electrical restitution
author_facet Kun-Tai Lee
Chih-Sheng Chu
Kai-Hung Cheng
Ye-Hsu Lu
Chih-Hsin Huang
Tsung-Hsien Lin
Ming-Chuan Lee
Sheng-Hsiung Sheu
Wen-Ter Lai
author_sort Kun-Tai Lee
title Effect of Short-term Cardiac Memory on Ventricular Electrical Restitution and QT Intervals in Humans
title_short Effect of Short-term Cardiac Memory on Ventricular Electrical Restitution and QT Intervals in Humans
title_full Effect of Short-term Cardiac Memory on Ventricular Electrical Restitution and QT Intervals in Humans
title_fullStr Effect of Short-term Cardiac Memory on Ventricular Electrical Restitution and QT Intervals in Humans
title_full_unstemmed Effect of Short-term Cardiac Memory on Ventricular Electrical Restitution and QT Intervals in Humans
title_sort effect of short-term cardiac memory on ventricular electrical restitution and qt intervals in humans
publisher Wiley
series Kaohsiung Journal of Medical Sciences
issn 1607-551X
publishDate 2009-02-01
description Cardiac memory (CM) can alter the configuration of action potentials and the transmural repolarization gradient in ventricular tissue. This study evaluated the effects of CM on ventricular arrhythmogenicity. A total of 20 patients (12 females, 8 males; mean age, 46 ± 13 years) were enrolled. The following indicators were measured to evaluate ventricular arrhythmogenicity: (1) the action potential duration at 90% repolarization (APD 90) recorded from the right ventricular apex (RVA); (2) the maximal slope of the action potential duration restitution curve (APDR) constructed by programmed extra stimuli from RVA; and (3) the maximal corrected QT interval (QTc) and QT interval dispersion (QTd). The short-term CM was induced by constant pacing from the RVA at a pacing cycle length (PCL) of 400 ms for 20 minutes. After induction of CM, the mean APD 90 were significantly shortened at both PCLs of 600 ms and 400 ms (252.9 ± 6.4 ms vs. 235.6 ± 6.4 ms and 231.2 ± 6.4 ms vs. 214.4 ± 7.3 ms, respectively; p = 0.001). No significant change regarding the maximal slopes of APDR were found at both PCLs of 600 ms and 400 ms (1.05 ± 0.09 vs. 0.96 ± 0.11 and 0.85 ± 0.08 vs. 0.84 ± 0.09, respectively). QTc (417.3 ± 9.1 ms vs. 454.7 ± 8.3 ms; p = 0.001), but not QTd (63.4 ± 5.4 ms vs. 65.7 ± 6.1 ms), was significantly shortened. Short-term CM significantly decreased ventricular APD 90 and QTc, but did not significantly change the maximal slope of APDR or QTd. These results suggest that CM might not have a significant effect on ventricular arrhythmogenicity.
topic cardiac memory
QT interval
ventricular arrhythmias
ventricular electrical restitution
url http://www.sciencedirect.com/science/article/pii/S1607551X09700415
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