Accuracy of pacing system analyzers for the determination of sinus rhythm amplitude in an implantable cardioverter-defibrillator

The objective of this study was to compare the beat-by-beat differences in R-wave amplitudes measured manually with two pacing system analyzers (PSAs) and with an implantable cardioverter-defibrillator (ICD). Intracardiac electrograms (EGMs) were obtained during normal sinus rhythm from 40 patients who experienced a range of ventricular and/or atrial arrhythmias. An in-vitro testing system was used to reconstruct these EGMs with uniform R-wave amplitudes and supply the output signals to a PSA, ICD or strip chart recorder. R-wave amplitudes measured by each method were highly correlated to the manual measurement (r>0.85). The average amplitude measured by the manual method was 7.0+/-3.1 mV. Amplitudes for the Angeion ICD, SeaMED PSA, and Pace Medical PSA were 6.9+/-3.0, 8.3+/-3.7, 5.1+/-2.3 mV, respectively. A minimum of 8 mV measured with a PSA will most likely guarantee a minimum of 5 mV amplitude measured manually