DeltaT50--a new method to assess temporal ventricular repolarization variability.
J Electrocardiol
; 44(4): 477.e1-9, 2011.
Article
in En
| MEDLINE
| ID: mdl-21704223
ABSTRACT
BACKGROUND:
Increased beat-to-beat variability in cardiac repolarization time is a tentative risk marker of drug-induced torsades de pointes. We developed a new, automatic method based on the temporal variability of the T-wave down slope to assess this variability. METHOD ANDRESULTS:
Leads V(1) to V(6) of resting electrocardiograms were recorded in 42 healthy subjects (18-68 years, 22 men). The temporal variability at 50% of the T-wave down slope, deltaT50 (1.5 ± 0.41 milliseconds; range, 0.86-2.66 milliseconds), was measured with an accuracy of 1 millisecond on at least 9 pairs of electrocardiogram complexes with a signal-to-noise ratio more than 10 and changes in the R-R interval less than 150 milliseconds. The correlation between repeated measurements of deltaT50 was high. DeltaT50 was measured without corrections for age, sex, heart rate, T-wave amplitude, signal-to-noise ratio, R-R variability, and QTcF because none of these factors explained more than 4% of the within-subject deltaT50 variability.CONCLUSION:
The beat-to-beat repolarization variability was measured with high fidelity with the deltaT50 method and was a robust measure in healthy volunteers.
Full text:
1
Database:
MEDLINE
Main subject:
Electrocardiography
/
Heart Conduction System
Type of study:
Prognostic_studies
Limits:
Adolescent
/
Adult
/
Aged
/
Aged80
/
Female
/
Humans
/
Male
/
Middle aged
Language:
En
Journal:
J Electrocardiol
Year:
2011
Type:
Article
Affiliation country:
Sweden