Assessment of QT-measurement accuracy using the 12-lead electrocardiogram derived from EASI leads.
The purpose of the present study is to assess QT-interval measurements from the EASI 12-lead electrocardiogram (ECG) as compared with the standard 12-lead ECG. The QT interval was automatically determined in simultaneously recorded standard and EASI 12-lead ECGs, using a validated wavelet-based delineator. The agreement between the 2 sets of measurements was quantified both on a lead-by-lead basis and a multilead basis with global definitions of QRS onset and T-wave end. The results show that the agreement between QT-interval measurements from the 2 lead systems is acceptable, with negligible mean differences and with correlation coefficients ranging from 0.91 to 0.98 depending on the lead studied. Although the SD shows a clear dependence on the selected lead (ranging from 9.2 to 26.4 milliseconds), differences are within the accepted tolerances for automatic delineation. In a few patients, large differences were found, mainly because of changes in morphology present in both lead systems. QT intervals measured by the multilead approach were considerably more stable than single-lead measurements and resulted in a much better agreement between the 2 lead systems (correlation coefficient, 0.98; QT difference, 1.1 +/- 9.8 milliseconds). Thus, the EASI 12-lead ECG may be used for reliable QT monitoring when the multilead delineation approach is adopted.
Martínez
Juan Pablo
JP
Aragon Institute of Engineering Research, Universidad de Zaragoza, 50015 Zaragoza, Aragon, Spain. jpmart@unizar.es
Laguna
Pablo
P
Olmos
Salvador
S
Pahlm
Olle
O
Pettersson
Jonas
J
Sörnmo
Leif
L
D003936:Diagnosis, Computer-Assisted / Q000295:instrumentation* / Q000706:statistics & numerical data*; D004562:Electrocardiography / Q000295:instrumentation* / Q000706:statistics & numerical data*; D004566:Electrodes; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006801:Humans; D008133:Long QT Syndrome / Q000175:diagnosis*; D015588:Observer Variation; D010818:Practice Patterns, Physicians'; D011379:Prognosis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016896:Treatment Outcome