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Use of a novel transfer function to reduce repolarization interval hysteresis

Journal of interventional cardiac electrophysiology. 2010 Oct ; 29 (1) : 23-32. [epub] 20100713

J Interv Card Electrophysiol
ISSN 1572-8595 | 1383-875X
Source

Language English Country Netherlands Media print-electronic

Document type Comparative Study, Journal Article, Research Support, Non-U.S. Gov't

Persistent link https://www.medvik.cz/link/pmid20625805

PubMed 20625805
DOI 10.1007/s10840-010-9500-x
Knihovny.cz E-resources

MeSH
Adult MeSH
Electrocardiography * MeSH
Risk Assessment MeSH
Hypertension diagnosis physiopathology MeSH
Cardiac Pacing, Artificial methods MeSH
Pacemaker, Artificial * MeSH
Cohort Studies MeSH
Middle Aged MeSH
Humans MeSH
Adolescent MeSH
Young Adult MeSH
Models, Cardiovascular MeSH
Follow-Up Studies MeSH
Heart Conduction System physiopathology MeSH
Reference Values MeSH
Aged, 80 and over MeSH
Aged MeSH
Heart Rate physiology MeSH
Long QT Syndrome diagnosis therapy MeSH
Treatment Outcome MeSH
Check Tag
Adult MeSH
Middle Aged MeSH
Humans MeSH
Adolescent MeSH
Young Adult MeSH
Male MeSH
Aged, 80 and over MeSH
Aged MeSH
Female MeSH
Publication type
Journal Article MeSH
Research Support, Non-U.S. Gov't MeSH
Comparative Study MeSH

BACKGROUND: Cardiac repolarization is assessed by the QT interval on the surface electrocardiogram and varies with the heart rate. Standard QT corrections (QTc) do not account for the lag in QT change following a change in heart rate (QT hysteresis). Our group has developed and tested a transfer function (TRF) model to assess the effectiveness of a dynamic model of QT/RR coupling in eliminating hysteresis. METHODS: We studied three groups: group I, healthy volunteers (n = 23, 41 ± 17 years); group II, hypertensive patients (n = 25, 45 ± 11 years); and group III, patients in a predominately paced rhythm (n = 5, 75 ± 6 years). To vary the heart rate, either exercise bicycling in the supine position (groups I and II) or manipulation of the pacemaker parameters (group III) was done. We then compared a dynamic TRF model with a model based on weighted averages of previous RR intervals. Two parameters were tested: root mean square (RMS) of the error signal between measured and computed QT and the elimination of hysteretic loops. RESULTS: TRF-based measurements eliminated hysteresis in 22/23 (95%) group I patients, 21/25 (84%) group II patients, and 4/5 (80%) group III patients. When hysteresis elimination was not complete, the QT drift that followed RR intervals was different before and after bicycling (100 ms). In these patients, the corresponding QT interval did not significantly change during this period. The TRF model was found superior to the other tested models with respect to both analyzed parameters (RMS and hysteresis elimination). CONCLUSION: The TRF model limited QT hysteresis in healthy, hypertensive, and pacemaker-dependent patients. In addition, an important finding of QT drift in patients with hypertension was identified. With further study in these and other diseased states, the TRF model may improve our ability to measure accurately cardiac repolarization and to determine arrhythmia risk.

Institute of Scientific Instruments Brno Czech

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