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Table of Contents
12-lead electrocardiogram
Resting ECGs were taken in participants aged 13 years and older who participated in 1A Visit 1 and 2A Visit 1.
This ECG measures electrical activity of the heart during rest, summarized in 12 leads.
The ECG provides many (>400) different variables at once, both quantitative and qualitative traits. These include duration, voltage and configuration characteristics. For example, information is provided of the cardiac rhythm, heart rate, the function of the sinoatrial and the atrioventricular node, atrial size, left ventricular mass, and repolarisation time (e.g. QT time).
Device
Welch Allyn CardioPerfekt Workstation ecg_manual.pdf
Welch Allyn CardioPerfect Workstation Software ecg_software_manual.pdf
DT100 vacuum units (suction electrode system).
Protocol
Electrodes were placed with conduction spray on ten clean spots at the abdomen and left side of the chest of lying participants (see illustration). In case of dextrocardia, the electrodes were mirrored.
All ECGs were checked by the research nurse and the Welch Allyn algorithm using CardioPerfekt software (see flow chart). ECG deviations (atrium fibrillation, atrium flutter, bradycardia, tachycardia, infoaction, acute ischemia, ST elevation, Wolff Parkinson White Syndrome, bigemenia, Left Bundle Branch Block, >1 premature ventricular contraction, second or third grade AV-block, pacemaker) were reported to a cardiologist.
Variables
The ECG resulted in the following variables:
| English | Variable | Assessment | Age |
| Test Code | TCODE | 2A Visit 1 | 13+ |
| Total presentations or trials. | PRESNT | 2A Visit 1 | 13+ |
| Total correct responses | COR | 2A Visit 1 | 13+ |
| Total error responses (includes FPos, FNeg, anticipations and max outs). | ERR | 2A Visit 1 | 13+ |
| Speed measure - mean of the log10 transformed reaction time for correct responses | LMNTRANS | 2A Visit 1 | 13+ |
| Speed measure - mean of reaction time for correct responses | LMNUNTRANS | 2A Visit 1 | 13+ |
| Speed measure - standard deviation of the log10 transformed reaction time for correct responses | LSD | 2A Visit 1 | 13+ |
| Accuracy measure - arcsine square root transformed - hitrate (correct responses divided by total responses (total includes TPos, TNeg, FPos, FNeg, anticipations and max outs) | ACCTRANS | 2A Visit 1 | 13+ |
| Accuracy measure - hit rate (correct responses divided by total responses (total includes TPos, TNeg, FPos, FNeg, anticipations and max outs) | ACCUNTRANS | 2A Visit 1 | 13+ |
| CPAL and ISLT specific - “Stimuli”. For CPAL is total filled markers, and for ISLT is total words in the presented list. | STI | 2A Visit 1 | 13+ |
