The Relationship Between Left Ventricular Systolic Function And Cerebral Blood Flow

Abstract

PURPOSE: The positive relationship between cardiac output and cerebral blood flow (CBF) has been indicated in healthy individuals and patinets with cardiovascular diseases. Previous studies reported that the reduced cardiac output was related with a low brain volume and an increased risk for Alzheimer’s disease. Also, compromised left ventricular (LV) diastolic function was reported to be associated with a cerebral white matter lesions. Therefore, cardiac function may play an important role for the maintenance of CBF. However, the relationship between LV systolic function and CBF is still unclear. The purpose of this study was to test our hypothesis that the LV systolic function would be associated with CBF. METHODS: Sixty-three outpatients who presented to our hospital due to transient loss of consciousness were enrolled (59 ± 22 years old, rang 17 to 93 years old, 31 females). LV function was assessed by stroke volume (SV), LV ejection fraction (LVEF) and mass (LVmass) by echocardiography, and preejection period (PEP), ejection time (ET) and ET/PEP by phonocardiogram. ET was corrected by heart rate (ETc). On the other hand, CBF was estimated from systolic, diastolic and mean blood flow velocity in middle cerebral artery (MCA), measured by transcranaial Doppler ultrasound. The multiple linear regression analysis was performed using MCA blood flow velocities (MCAv) as independent variables, and age, sex and each LV funtion as dependent variables. RESULTS: SV, LVEF, LVmass and PEP were not correlated with MCAv. In contrast, ETc was significantly correlated with both systolic (β = 0.32, P = 0.01) and mean (β = 0.25, P = 0.02) MCAv. ET/PEP was significantly correlated with systolic MCAv (β = 0.22, P = 0.04) only. CONCLUSIONS: These results indicated that LV systolic function evaluated by phonocardiogram may play more siginifcant role for regulating CBF as compared with that by echocardiography such as LVEF.