Relationship of plasma brain-type natriuretic peptide levels to left ventricular longitudinal function in patients with congestive heart failure assessed by strain Doppler imaging

Abstract

Background Plasma brain-type natriuretic peptide (BNP) levels have been used to diagnose congestive heart failure (CHF), but significant heterogeneity in BNP levels is not explained by standard echocardiographic indexes of cardiac function. Recent data indicate that longitudinal left ventricular (LV) dysfunction exists in the presence of normal standard echocardiographic indexes and BNP was predicted well by LV longitudinal systolic velocity. We examined whether longitudinal LV function assessed by strain or strain rate (SR) tissue Doppler imaging could be determinants of plasma BNP levels in patients with CHF. Methods We examined 137 consecutive patients with suspected CHF. Standard echocardiography and Doppler flow records were obtained. Strain, and SR at the basal and mid parts of the ventricle were investigated in 2 apical views. Tissue velocities of mitral annulus were also obtained. Plasma BNP levels were measured on the day of echocardiography. Results Multivariate analysis showed the mean longitudinal LV strain ( r = 0.75, P < 0.0001) to be an independent powerful predictor of plasma log BNP levels. Subgroup analysis (ejection fraction < 50%, n = 30; ejection fraction > 50%, n = 107) also showed that the mean longitudinal LV strain ( r = 0.89, P < 0.0001; r = 0.68, P < 0.0001, respectively) was only an independent predictor of log BNP levels. Conclusion Longitudinal LV strain is closely related to log BNP levels in patients with CHF, both in patients with systolic and diastolic heart failure.