Computer analysis of the electrocardiogram during esophageal pacing cardiac stress

The authors describe the development of a robust signal processing algorithm for interpretation of the surface electrocardiogram (ECG) during transesophageal atrial pacing stress. The algorithm uses novel schemes using both linear and nonlinear transformations to detect and differentiate between the pacing artifact and the QRS complex, even in difficult situations where the pacing artifact is in proximity to or superimposed on the QRS complex. The algorithm uses sophisticated logic for automatic recognition of sustained capture. It subsequently calculates beat-by-beat and average (over five beats) ST segment amplitude and slope. The algorithm also reports the instantaneous heart rate, RR interval, pace-to-R interval, R-wave amplitude. and estimated sinus node recovery time upon loss of sustained capture. The limitations of present exercise ECG computer methods in processing the ECG during transesophageal atrial pacing stress are evaluated and significantly improved performance by the algorithm is demonstrated.