The American journal of cardiology
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Comparative Study
Evaluation of five QT correction formulas using a software-assisted method of continuous QT measurement from 24-hour Holter recordings.
To evaluate and compare QT correction formulas in healthy subjects, we used 24-hour Holter monitoring because it allows the assessment of QT intervals over a large range of rates. Computer-assisted QT-interval measurements were obtained from 21 subjects. QT-RR relations for individuals and the group were fitted by regression analysis to 5 QT prediction formulas: simple Bazett's, modified Bazett's, linear (Framingham), modified Fridericia's and exponential (Sarma's). ⋯ Determination of these parameters requires long-term recording to obtain an adequate range of rates. Group-based regression parameters give poor correction. When individual parameters cannot be determined, as in a 12-lead electrocardiogram, no formula provides an advantage over the familiar simple Bazett's.