cliot (version 1.0.0)

calculate_qtc: Corrected QT Interval (QTc) Calculator

Description

Calculates the Corrected QT Interval (QTc) using four standard formulas: Bazett, Fridericia, Framingham, and Hodges. The QTc adjusts the measured QT interval for heart rate, allowing for the assessment of repolarization abnormalities (e.g., Long QT Syndrome) regardless of the patient's pulse.

Usage

calculate_qtc(qt_interval_msec, heart_rate_bpm)

Value

A list containing:

QTc_Bazett

QTc calculated via Bazett's formula.

QTc_Fridericia

QTc calculated via Fridericia's formula.

QTc_Framingham

QTc calculated via Framingham's formula.

QTc_Hodges

QTc calculated via Hodges' formula.

Arguments

qt_interval_msec

Numeric. The measured QT interval in milliseconds (from the beginning of the Q wave to the end of the T wave).

heart_rate_bpm

Numeric. The patient's heart rate in beats per minute.

Details

Formulas used:

• Bazett: \(QTc = QT / \sqrt{RR}\) (Most common, but overcorrects at high heart rates).

• Fridericia: \(QTc = QT / \sqrt[3]{RR}\).

• Framingham: \(QTc = QT + 154 \times (1 - RR)\).

• Hodges: \(QTc = QT + 1.75 \times (HR - 60)\).

Where \(RR = 60 / HR\).

References

Bazett HC. An analysis of the time-relations of electrocardiograms. Heart. 1920;7:353-370. Fridericia LS. Die Systolendauer im Elektrokardiogramm bei normalen Menschen und bei Herzkranken. Acta Medica Scandinavica. 1920;53:469-486.

Examples

# Example 1: Normal Heart Rate
# QT 400 ms, HR 60 bpm (RR = 1 sec)
# All formulas should yield approx 400 ms
calculate_qtc(400, 60)

# Example 2: Tachycardia
# QT 320 ms, HR 100 bpm
# Bazett overcorrects compared to others
calculate_qtc(320, 100)