Atrial paced rhythm and heart rate-dependent worsening of left atrial and ventricular function

Background and aim of the study: The response to the increase in heart rate (HR) could be characterized by failure in both left ventricular (LV) and left atrial (LA) functions. This study aimed to evaluate the relationship between the increase in paced HR and the changes in LV and LA functions, assessed by two-dimensional speckle tracking analysis. Methods: In a group of patients with an implantable cardioverter defibrillator (ICD) or pacemaker, the atrial paced rhythm was progressively increased from 60 to 70, from 70 to 80, and from 80 to 90 beats per minute (bpm). For each paced HR, using two-dimensional speckle tracking analysis, LA reservoir (LAr), LA conduit (LAc), LA contraction (LAct), and LV global longitudinal strain (LV-GLS) were evaluated every 10 bpm. Results: Of the 45 patients enrolled, a significant reduction in LAr was observed at higher HR. However, when the patients were dichotomized according to the HR-related response of LV-GLS, the worsening of LAr was observed in those with LV-GLS worsening and not in those without (maximum LAR absolute changes −2.7 ± 7.2% vs. +2.7 ± 7.2%, respectively, p.028). Moreover, the worsening of LA and LV strain measures was associated with an increase in the estimated filling pressures. Conclusions: In patients with atrial paced rhythm, the increase in HR could be associated with worsening of LA and LV functions, as assessed by two-dimensional speckle tracking analyses. These results offer new data on HR-related atrioventricular function and could be useful for guiding the optimal HR responsiveness of the implanted devices.