Ecg Rhythm Analysis Algorithm Accuracy - ZOLL R Series Service Manual

ECG Rhythm Analysis Algorithm Accuracy

Sensitivity and specificity are expressions of ECG rhythm analysis algorithm performance
when compared to ECG interpretation by a clinician or expert. Sensitivity refers to the
algorithm's ability to correctly identify shockable rhythms (as a percentage of the total number
of shockable rhythms). Specificity refers to the algorithm's ability to correctly identify
nonshockable rhythms (as a percentage of the total number of nonshockable rhythms).
The data in Table A-4 and Table A-5 summarize the accuracy of the ECG rhythm analysis
algorithm as tested against ZOLL's ECG rhythm database. Rhythm sources included data
records from ZOLL devices and public domain databases recorded with electrode systems and
ECG signal processing characteristics similar to the R Series. Data records were of appropriate
length to allow for satisfactory analysis.
The algorithm sequence takes approximately 9 seconds and proceeds as follows:
Divides the ECG rhythm into 3-second segments
•
Filters and measures noise, artifact, and baseline wander
•
Measures baseline content ("waviness" at the correct frequencies – frequency domain
•
analysis) of signal
Measures QRS rate, width, and variability
•
Measures amplitude and temporal regularity (autocorrelation) of peaks and troughs
•
Determines if multiple 3-second segments are shockable and then prompts the operator to
•
treat the patient
Table A-4. Clinical Performance Results (Adult Patients)
Rhythms
Shockable
Coarse VF
Rapid VT
Nonshockable
NSR
AF, SB, SVT, heart block,
idioventricular, PVCs
Asystole
Intermediate
Fine VF
Other VT
9650-0912-01 Rev. N

ECG Rhythm Analysis Algorithm Accuracy

Sample Performance
Size Goals
Sensitivity
536 >90%
80 >75%
Specificity
2210 >99%
819 >95%
115 >95%
69 Report only
28 Report only
ZOLL R Series Operator's Guide
Observed 90% One-sided Lower
Performance Confidence Limit
100.0% 99.4%
100.0% 96.3%
100.0% 99.9%
99.9% 99.4%
100.0% 97.4%
89.9% 81.8%
96.4% 84.2%
A–29