ZOLL AED Pro Rev J - Manual (Page 103)

ECG Analysis Algorithm Accuracy
9650-0350-01 Rev. J ZOLL AED Pro Operator’s Guide A–15
ECG Analysis Algorithm Accuracy
Sensitivity and specificity are expressions of ECG 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 analysis algorithm as
tested against the ZOLL ECG rhythm database.
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
Sample
Size
Performance
Goals
Observed
Performance
90% One-sided Lower
Confidence Limit
Shockable 466 Sensitivity
Coarse VF 403 >90% 96.28% 94.33%
Rapid VT 63 >75% 100.0% 95.36%
Nonshockable 2305 Specificity
NSR 1659 >99% 100.0% 99.82%
AF, SB, SVT, heart block,
idioventricular, PVCs 604 >95% 100.0% 99.51%
Asystole 42 >95% 100.0% 93.12%
Intermediate 68
Fine VF 50 Report only 92.00% 82.62%
Other VT 18 Report only 88.89% 68.97%