# Validación clínica de una nueva fórmula para el cálculo del intervalo QT corregido

### Impacto

Cobos Gil, Miguel Ángel (2018) Validación clínica de una nueva fórmula para el cálculo del intervalo QT corregido. [Thesis]

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## Resumen (otros idiomas)

The QT interval measures the global duration of the electrical activity of the ventricular myocardium. Repolarization plays a determining role in the normal function of the heart, and is often responsible for the development of arrhythmias. QT prolongation is a marker of abnormal repolarization, and it is a risk factor for arrhythmias and sudden death in many cardiac conditions, and even in the general population. Because the duration of QT interval depends upon the heart rate, the QT interval should be corrected for cardiac frequency. Of the man y formulas proposed for the correction of the QT interval, the one developed by Bazett, remains the most used in practice: QTc = QT/√RR. The popularity of the Bazett formula is based on its apparent simplicity, not on its merit. Based upon mathematical considerations, we hypothesize that the very simple formula: QTc=QT/ (l+RR)/2. would provide an accurate correction. Additionally, our new formula offers an easy, eyeballing method to diagnose QT prolongation. To test our new formula, QT and RR data were recovered from 19 large population studies reported in the literature. The QT and RR intervals were used to calculate the QTc by use of the new formula and other four different heart rate correction formulae: Bazett, Fridericia (QTc = QT/3√RR], Hodges (QTc = QT + 1.75 *(HR-60)], and Framingham (QTc = QT + 0.154*(1-RR)]. The slope of QTc-RR regression line for each QTc formula was detemúned and used to compare QT c formulae. Regression line slopes close to zero indicate a satisfactory correction. Further, we used the five formulae in two samples of adult patients in our setting. Generally, Bazett's formula pro vides the worst correction, the others four formulae have a similar accuracy. We conclude that the new QTc formula is more accurate than Bazett's correction and more convenient than the other formulae. We think that our new formula can be very useful in the routine clinical evaluation of the QT interval.

Item Type:Thesis

Directors:
DirectorsDirector email
Macaya Miguel, Carlos
Uncontrolled Keywords:Electrocardiografía, Intervalo QT
Palabras clave (otros idiomas):Electrocardiography, QT interval
Subjects:Medical sciences > Medicine > Cardiology
ID Code:47175
Deposited On:16 Apr 2018 08:18