Document Detail

Effects of pink grapefruit juice on QT variability in patients with dilated or hypertensive cardiomyopathy and in healthy subjects.
MedLine Citation:
PMID:  18433709     Owner:  NLM     Status:  MEDLINE    
Recent evidence shows that pink grapefruit juice, which is a recommended dietary addition that contains high amounts of the antioxidant flavonoid naringenin, prolongs the corrected QT (QT(c)), a noninvasive electrophysiological marker of spatial myocardial repolarization, and does so by inhibiting the rapid component of the delayed rectifier K+ current (I(Kr)). Prompted by the observation that all class III antiarrhythmic drugs inhibit this current, thereby sometimes provoking torsades de pointes, we compared the effects of a liter of freshly squeezed pink grapefruit juice with those of 2 commonly used class III antiarrhythmics amiodarone and sotalol on the major noninvasive markers of temporal variability in myocardial repolarization used to stratify the risk of sudden death from malignant ventricular arrhythmias. In 32 subjects, 10 with postischemic dilated cardiomyopathy, 12 with hypertensive cardiomyopathy, and 10 healthy, we assessed QT(c) and QT variability index (QTVI) after administration of fresh pink grapefruit juice, placebo, amiodarone, or sotalol. After pink grapefruit juice and sotalol, all these indexes increased significantly from values observed after placebo (P<0.05) and from values after amiodarone (P<0.05). Conversely, after amiodarone, QT(c), but not QTVI, increased significantly from values after placebo (P<0.05). Presumably because of its high naringenin glycoside content, pink grapefruit juice prolongs cardiac repolarization and concurrently increases temporal cardiac repolarization dispersion. The potential proarrhythmic actions of pink grapefruit juice might be of concern in patients with major myocardial structural disorders.
Gianfranco Piccirillo; Damiano Magrì; Sabrina Matera; Marzia Magnanti; Eleonora Pasquazzi; Erika Schifano; Stefania Velitti; Marilena Mitra; Vincenzo Marigliano; Marino Paroli; Andrea Ghiselli
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Publication Detail:
Type:  Controlled Clinical Trial; Journal Article     Date:  2008-04-09
Journal Detail:
Title:  Translational research : the journal of laboratory and clinical medicine     Volume:  151     ISSN:  1931-5244     ISO Abbreviation:  Transl Res     Publication Date:  2008 May 
Date Detail:
Created Date:  2008-04-24     Completed Date:  2008-07-30     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101280339     Medline TA:  Transl Res     Country:  United States    
Other Details:
Languages:  eng     Pagination:  267-72     Citation Subset:  AIM; IM    
Dipartimento di Scienze dell'Invecchiamento, Dipartimento di Scienze Cardiovascolari, Respiratorie e Morfologiche, Policlinico Umberto I, Università degli Studi di Roma La Sapienza, Roma, Italy.
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MeSH Terms
Administration, Oral
Amiodarone / administration & dosage*
Anti-Arrhythmia Agents / administration & dosage
Cardiomyopathy, Dilated / physiopathology*
Citrus paradisi*
Double-Blind Method
Electrocardiography / drug effects
Heart Conduction System / drug effects,  physiology,  physiopathology
Hypertension / physiopathology
Long QT Syndrome / physiopathology
Middle Aged
Sotalol / administration & dosage*
Reg. No./Substance:
0/Anti-Arrhythmia Agents; 1951-25-3/Amiodarone; 3930-20-9/Sotalol

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