Table 2.
Measured and calculated parameters in electrocardiographic tracings at pre-and post-exercise in Lead II of 74 healthy children aged 5 to 12 years
| 20 measured parameters at pre- and post-exercise | |
|---|---|
| Amplitudes of waves | Amplitudes of P wave, Q wave, R wave, S wave, T wave, and U wave |
| Durations or waves | Durations of P wave and P wave time to peak, QRS , T wave and T wave time to peak and U wave |
| Duration of intervals | PR, QT, QoT, JT, JTP, Tp-e [Figure 1] |
| (QT: Onset of Q wave to the end of T wave, QoT: onset of Q to onset of T wave, JT: J point to the end of T wave, JTP: J point to peak of T wave, Tp-e: Peak of T wave to end of T wave, Tp-e/QT: peak of T wave to end of T wave/QT) | |
| ECG-derived estimation of duration of systole=Equivalent to JT interval as shown in the simplified Wiggers diagram in Figure 2 | |
| ECG-derived estimation of duration of diastole=RR interval-JT interval as shown in the simplified Wiggers diagram in Figure 2 | |
|
| |
| 25 Calculated parameters at preexercise and postexercise | |
|
| |
| Heart-rate corrected by four heart-rate correction formulas | QTc by four formulas, QoTc by four formulas, JTc by four formulas, JTPc by four formulas and Tp-e/QTc by four formulas |
| Absolute QT shortening=QT interval at preexercise-QT interval at postexercise | |
| QT shortening fraction=QT interval at preexercise-QT interval at postexercise/QT interval at preexercise×100 | |
| Systolic to diastolic time ratio=duration of systole/duration of diastole | |
| Bazett’s formula=Interval/√RR interval | |
| Fridericia formula=Interval/3√RR interval | |
| Framingham’s formula=Interval+0.154× (1-RR interval) | |
| Hodge’s formula=interval+1.75× (HR-60)] | |
| Percentage of decrease in ECG-derived estimated duration of systole=(preexercise duration of systole-postexercise duration of systole/preexercise duration of systole) ×100 | |
| Percentage of decrease in ECG-derived estimated duration of diastole=(preexercise duration of diastole-postexercise duration of diastole/preexercise duration of diastole) ×100 | |
QoT: Onset of Q to onset of T, JT: J point to end of T wave, QTc: Corrected QT, JTP: J point to peak T interval, Tp-e: T peak-T end interval, QT: Onset of Q wave to the end of T wave, QoTc: Onset of Q to onset of T, ECG: Electrocardiographic, HR: Heart rate, JTc: Corrected JT interval, JTPc: Corrected J point to peak T interval, QRS: QRS complex, PR: PR interval