IDENTIFICATION OF SYSTOLIC TIME INTERVALS USING PEAK ENDOCARDIAL ACCELERATION SONR SENSOR SIGNAL
S. Hoenig, A. Kypta, K. Saleh, T. Lambert, A. Nahler, H. Blessberger, J. Kammler, B. Pfeifer, J. Auer, F.Gurtner, C. Steinwender
1. 1st Medical Department, Cardiology,Medical School of the Kepler University Linz, Linz, Austria; 2. Institute of Electrical and Biomedical Engineering , University for Medical Informatics and Technology Tyrol, Hall, Austria; 3. St. Josef Hospital Braunau, Department of Cardiology and Intensive Care, Braunau, Austria
Purpose: Systolic Time Interval measurement (STI) is an established non invasive method to test ventricular performance by using a function of time instead of force and distance. STI provides a quantitative estimate of cardiovascular disease effects in left ventricle. Especially the pre-ejection period (PEP), the electro mechanical activation time (EMAT, QS1), the left ventricular ejection time (LVET) and the total mechanical systole (QS2) is of interest.
Methods: In our pilot study we investigated if the STI measurements can be done by using an integrated sensor (SonRTip, Sorin Group) that is able to measure beside intracardial electrograms the peak endocardial acceleration signals (S1, S2) in order to optimize the AV and VV timing intervals in cardiac resynchronization patients. Therefore the EMAT and the QS2 timing intervals where measured using the gold standard ECHO and were compared with the obtained SonR measurements.
Results: In seven patients STI measurements were done and the signals of all intervals were derived and compared to the ECHO measurements. After removing outliers we obtained a good correlation with r=0.58 for EMAT and r=0.64 for QS2.
Conclusions: In this study we were able to show that STI can be permanently measured using SonR signal. More patient data are needed to overcome the limitations of this pilot and to enable diagnostic and/or therapeutic benefit.
Figure 1. a depicts the intracardial electrogram in the first and the peak endocardial acceleration signal in the second line that were used for STI extraction.
Figure 2. depicts the measured ECHO superimposed by the peak endocardial acceleration signal.
