| Heart rate-dependence of QTc intervals assessed by different correction methods in patients with normal or prolonged repolarization. | |
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MedLine Citation:
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PMID: 20025715 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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BACKGROUND: There is a continuing debate about the optimal method for QT interval adjustment to heart rate changes. We evaluated the heart rate dependence of QTc intervals derived from five different QT correction methods. METHODS: Study patients (n = 123, age 68 +/- 11 years) were dual-chamber device recipients with baseline normal or prolonged QT interval who had preserved intrinsic ventricular activation with narrow QRS complexes. Patients were classified to either Normal-QT (n = 69) or Prolonged-QT (n = 54) groups. Serial QT intervals were recorded at baseline (52 +/- 3 beats per minute) and following atrial pacing stages at 60, 80, and 100 beats per minute. The QTc formulae of Bazett, Fridericia, Sagie-Framingham, Hodges, and Karjalainen-Nomogram were applied to assess the effect of heart rate on the derived QTc values by using linear mixed-effects models. RESULTS: Heart rate had a significant effect on QTc regardless of the formula used (P < 0.05 for all formulae). The Bazett's formula demonstrated the highest QTc variability across heart rate stages (highest F values) in both patient groups (in the total cohort, F = 175.9). In the following rank order, the formulae Hodges, Karjalainen-Nomogram, Sagie-Framingham, and Fridericia showed similar QTc heart rate dependence at both slower and faster heart rates in both patient groups (F = 21.8, 25.6, 28.8, 36.9, in the total cohort, respectively). CONCLUSIONS: Of the studied QTc formulae, the Bazett appeared the most heart rate dependent. Our results suggest the use of Hodges and the Karjalainen-Nomogram secondly to ensure least heart rate dependence of QTc intervals in patients with either normal or prolonged repolarization. |
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Authors:
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John Chiladakis; Andreas Kalogeropoulos; Panagiotis Arvanitis; Nikolaos Koutsogiannis; Fani Zagli; Dimitrios Alexopoulos |
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Publication Detail:
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Type: Journal Article Date: 2009-12-18 |
Journal Detail:
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Title: Pacing and clinical electrophysiology : PACE Volume: 33 ISSN: 1540-8159 ISO Abbreviation: Pacing Clin Electrophysiol Publication Date: 2010 May |
Date Detail:
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Created Date: 2010-06-15 Completed Date: 2010-09-27 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 7803944 Medline TA: Pacing Clin Electrophysiol Country: United States |
Other Details:
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Languages: eng Pagination: 553-60 Citation Subset: IM |
Affiliation:
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Cardiology Department, Patras University Hospital, Patras, Greece. chil@otenet.gr |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Aged Aged, 80 and over Arrhythmias, Cardiac / physiopathology* Defibrillators Electrocardiography Female Heart Rate / physiology* Humans Long QT Syndrome / physiopathology* Male Middle Aged Pacemaker, Artificial |
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