electrocardiogram

What Is an Electrocardiogram?

An electrocardiogram (ECG/EKG) is a recording of the heart's electrical activity, consisting of the characteristic P, QRS, and T waveforms representing atrial depolarisation, ventricular depolarisation, and repolarisation. While ECG data have not proven directly diagnostic for PDD, research has explored whether ECG-derived features — particularly the R-R interval (heart rate variability) and the pre-ejection period — may provide useful supplementary information.

ECG vs. Polygraph Cardiograph

The standard polygraph cardiograph uses a blood pressure cuff to record the mechanical pulse wave — fundamentally different from the ECG's electrical recording. The cuff captures pressure changes from blood flow; the ECG captures electrical signals triggering each heartbeat. Both provide heart rate information, but the ECG reveals additional cardiac electrical timing the cuff cannot capture.

Research Applications

ECG-derived measures have been investigated for their potential to add diagnostic information beyond standard channels. Heart rate variability, pre-ejection period, and other indices have shown some promise. However, these have not been incorporated into validated test data analysis methods, and the standard three-channel configuration remains the basis for validated scoring.

Modern Instrument Capability

Some current digital polygraph systems can record ECG data alongside standard channels, providing supplementary information for identifying arrhythmias and premature beats that could affect cardiovascular data interpretation.