Influence of ECG measurement accuracy on ECG diagnostic statements

Area of Science:

• Biomedical Engineering
• Medical Informatics
• Cardiology

Background:

• Computerized electrocardiogram (ECG) analysis generates extensive data for diagnostics and databases.
• Lack of specified error limits for ECG measurements hinders systematic investigation of their diagnostic impact.

Purpose of the Study:

• To develop an analytical method for estimating the influence of measurement errors on diagnostic ECG statements.
• To assess the impact of International Electrotechnical Commission (IEC) interval measurement tolerance limits on ECG diagnoses.

Main Methods:

• Analytical method to quantify the effect of systematic errors (offset) and dispersion on diagnostic accuracy.
• Application of the method to ECG conduction defect diagnoses using IEC tolerance limits.

Main Results:

• Systematic errors shift the operating point on receiver operating characteristic (ROC) curves, increasing false positives/negatives.
• Measurement error dispersion broadens parameter distributions, flattening ROC curves and increasing classification errors.
• IEC tolerance limits may be too large, potentially causing over 30% false positive atrial and 10-18% false intraventricular conduction defect statements.

Conclusions:

• Measurement errors critically affect ECG diagnostic accuracy.
• Current IEC tolerance limits for ECG measurements may compromise diagnostic reliability.
• Recommends systems provide error tolerance limits on defined test sets for long-term ECG database usability.