Correct the QT interval for heart rate with the Bazett, Fridericia, Framingham and Hodges formulas, and flag the prolongation thresholds for each method.
QTc 延长与心律失常风险相关;公式下拉框决定实际使用的校正公式,性别决定正常上限。
| Item | Formula / Note | Source / Standard |
|---|---|---|
| Correction formula | the Bazett correction divides by the square root of the cycle length | Bazett 1920, Heart |
| Alternative formula | the Fridericia formula stays stable when heart rate departs from normal | Fridericia 1920, Acta Med Scand |
| Prolongation criteria | values beyond four hundred fifty and four hundred sixty milliseconds are prolonged | AHA/ACCF/HRS 2009, ECG standardization |