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Published on: December 11, 2019
Electrocardiographic reference ranges derived from 79,743 ambulatory subjects
Jay W Mason1, Douglas J Ramseth, Dennis O Chanter
1Covance Cardiac Safety Services, Inc, Reno, NV 89521, USA. jay.mason@covance.com
Insights
Current electrocardiogram (ECG) reference ranges are outdated and do not reflect true age- and sex-related values. This study establishes new, modernized ECG reference ranges based on a large population using digital technology.
Area of Science:
- Cardiology
- Medical Diagnostics
- Biostatistics
Background:
- Existing electrocardiogram (ECG) reference ranges are not representative of large populations and lack modern technological basis.
- Current norms for ECG intervals, heart rate, and QRS axis may not accurately reflect diverse age and sex demographics.
Purpose of the Study:
- To establish updated, age- and sex-specific reference ranges for ECG parameters using modern digital interpretation methods.
- To compare new reference ranges with existing norms and assess the impact of age and sex on ECG values.
Main Methods:
- Analysis of 79,743 baseline ECGs from clinical trials, interpreted digitally by cardiologists.
- Identification of a subgroup (n=46,129) with low cardiovascular disease probability for reference range determination.
- Calculation of reference ranges using 2nd and 98th percentiles for heart rate, PR, QRS, QRS axis, QT, and QTc intervals.
Main Results:
- Significant age- and sex-related variations were observed in all measured ECG parameters.
- New reference ranges were established: heart rate (48-98 bpm), PR interval (113-212 ms), QRS interval (69-109 ms), QRS axis (-40° to 91°), QT interval (325-452 ms), QTc-Bazett (361-457 ms), QTc-Fridericia (359-445 ms).
- Digital interpretation showed minimal differences compared to paper tracings and computer algorithms.
Conclusions:
- Modernized ECG reference ranges are significantly different from previously reported norms and general use values.
- Age and sex profoundly influence normal ECG values, necessitating updated reference standards.
- Large cohort studies are crucial for comprehensive assessment, and ECG reference ranges require modernization.
Background:
Reference ranges for electrocardiogram (ECG) intervals, heart rate, and QRS axis in general use by medical personnel and ECG readers are unrepresentative of true age- and sex-related values in large populations and are not based on modern electrocardiographic and ECG reading technology.
Methods And Results:
The results of ECG interpretation by cardiologists using digital technology for viewing and interpreting ECGs were compiled from single, baseline ECGs of 79,743 individuals included in pharmaceutical company-sponsored clinical trials. Women comprised 48% of the total population. Ages ranged from 3 months to 99 years, and the bulk of the population (56%) was aged 40 to 70 years. Striking differences in numerical ECG values based on age and sex were observed. A subgroup of 46,129 individuals with a very low probability of cardiovascular disease was identified. The following were the reference ranges for this subgroup, determined using the 2nd and 98th percentiles: heart rate, 48 to 98 beats/min; PR interval, 113 to 212 milliseconds; QRS interval, 69 to 109 milliseconds; frontal plane QRS axis, -40 degrees to 91 degrees ; QT interval, 325 to 452 milliseconds; QTc-Bazett, 361 to 457 milliseconds; and QTc-Fridericia, 359 to 445 milliseconds. There were marked age- and sex-related variations in the reference ranges of this subgroup, and they differ substantially from previously reported norms. Small differences were observed in ECG values obtained using our digital methods as compared with readings done using paper tracings and values computed by 2 commercial computer algorithms.
Conclusions:
We observed large differences in electrocardiographic heart rate, interval, and axis reference ranges in this study compared with those reported previously and with reference ranges in general use. We also observed a large influence of age and sex upon normal values. Very large cohorts are required to fully assess age- and sex-related variation of reference ranges. Electrocardiographic reference ranges should be modernized.
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