Recording of Peak Endocardial Acceleration in the Atrium

Background: The important role played by peak endocardial acceleration (PEA or sonR) in hemodynamic monitoring of cardiac resynchronization therapy (CRT) was recently highlighted in several studies with the sensor embedded in a right ventricular (RV) lead tip. This study examined the short- and long-term reliability of a right atrial (RA) sonR sensor. Methods: RA and RV sonR signals were measured from RA and RV leads respectively, at implant and up to 12 months of follow-up, in 19 recipients of either single chamber pacemakers or CRT systems. At 1 month of follow up, RA sonR signals and heart rate were simultaneously recorded during exercise. Results: A reliable RA sonR signal amplitude was measured at implant, proportional to the RV amplitude. We observed in both the right atrium and right ventricle (1) a similar signal noise ratio at implant, (2) a similar evolution of the sonR signal amplitude up to 12 months of follow-up, and (3) a high correlation between heart rate and RA sonR signal amplitude during exercise. Conclusions: The RA sonR signal was reliable and proportional to the RV signal on the short and long term, and reflected changes in activity. These observations suggest that the sonR sensor could be placed in the atrium for the hemodynamic monitoring of CRT system recipients.