Abstract
B-type natriuretic peptide (BNP) levels accurately reflect the degree of cardiac overload in heart failure. Considering cardiac morphology and intracardiac pressure, including the left ventricular end-systolic volume index (LVESVI) and left ventricular end-diastolic volume index (LVEDVI), is essential for cardiac overload assessment. These indexes influence plasma BNP levels, and an elevated heart rate affects cardiac morphology. However, the direct relationship between elevated heart rate and plasma BNP levels remains unknown. In this study, we simultaneously measured various hemodynamic parameters and BNP levels during cardiac catheterization in 5,429 inpatients with sinus rhythm at our hospital. Furthermore, we examined how heart rate affects cardiac morphology, intracardiac pressure, and plasma BNP levels via regression analysis and structure equation modeling (SEM). Univariate regression analysis revealed a significant positive correlation between heart rate and log BNP levels. The path model with SEM revealed significant positive relationships of heart rate and LVESVI with left ventricular end-diastolic pressure, in addition to a significant negative relationship of heart rate and LVEDVI with log BNP. Collectively, these findings suggest no positive relationship (rather, a negative relationship) between heart rate and log BNP and that elevated heart rate indirectly increases plasma BNP levels by altering cardiac morphology and intracardiac pressure.