Background: Reduced lead systems utilizing patient-specific transformation weights have been reported to achieve superior estimates than those utilizing population-based transformation weights. We report upon the effects of ischemic-type electrocardiographic changes on the estimation performance of a reduced lead system when utilizing patient-specific transformation weights and population-based transformation weights.
Method: A reduced lead system that used leads I, II, V2 and V5 to estimate leads V1, V3, V4, and V6 was investigated. Patient-specific transformation weights were developed on electrocardiograms containing no ischemic-type changes. Patient-specific and population-based transformations weights were assessed on 45 electrocardiograms with ischemic-type changes and 59 electrocardiograms without ischemic-type changes.
Results: For patient-specific transformation weights the estimation performance measured as median root mean squared error values (no ischemic-type changes vs. ischemic-type changes) was found to be (V1, 27.5 μV vs. 95.8 μV, P<.001; V3, 33.9 µV vs. 65.2 µV, P<.001; V4, 24.8 μV vs. 62.0 μV, P<.001; V6, 11.7 μV vs. 51.5 μV, P<.001). The median magnitude of ST-amplitude difference 60 ms after the J-point between patient-specific estimated leads and actual recorded leads (no ischemic-type changes vs. ischemic-type changes) was found to be (V1, 18.9 μV vs. 61.4 μV, P<.001; V3, 14.3 μV vs. 61.1 μV, P<.001; V4, 9.7 μV vs. 61.3 μV, P<.001; V6, 5.9 μV vs. 46.0 μV, P<.001).
Conclusion: The estimation performance of patient-specific transformations weights can deteriorate when ischemic-type changes develop. Performance assessment of patient-specific transformation weights should be performed using electrocardiographic data that represent the monitoring situation for which the reduced lead system is targeted.
Copyright © 2012 Elsevier Inc. All rights reserved.