Ethnic differences in left ventricular structure: relations to hemodynamics and diurnal blood pressure variation.
BACKGROUND
Previous studies have suggested that African Americans have a greater left ventricular relative wall thickness than whites with similar levels of blood pressure (BP), whereas other investigators have documented an attenuated nocturnal decline in BP and early remodeling of the resistance vessels in African Americans.


METHODS
To further evaluate the contributions of diurnal BP variation and vascular remodeling to ethnic differences in left ventricular geometry, we measured ambulatory BP, systemic hemodynamics, minimum forearm vascular resistance, and left ventricular structure in a biracial sample of 171 men and women between the ages of 25 and 45 years.


RESULTS
Despite similar resting BPs, African Americans had a greater indexed peripheral resistance, a greater minimal forearm vascular resistance, and a smaller nocturnal decline in BP than white subjects. African Americans also had a greater left ventricular relative wall thickness (0.41 +/- 0.07 v 0.38 +/- 0.08, P =.048) and a trend toward a greater indexed left ventricular mass (41.1 +/- 8.7 v 38.6 +/- 8.6 g/m(2.7), P =.087). Ethnic differences in relative wall thickness were no longer significant when adjusted for either indexed peripheral resistance (P =.173) or sleep systolic BP (P =.124).


CONCLUSIONS
In our cohort of young men and women, African Americans had a greater left ventricular relative wall thickness than whites with similar levels of resting BP. This early concentric remodeling of the left ventricle in African Americans may be mediated, in part, by hemodynamic influences, including a greater peripheral vascular resistance and a smaller nocturnal decline in BP.
Hinderliter
Alan L
AL
Department of Medicine, University of North Carolina, Chapel Hill, North Carolina 27599, USA. hinderli@med.unc.edu
Blumenthal
James A
JA
Waugh
Robert
R
Chilukuri
Mohan
M
Sherwood
Andrew
A
D000328:Adult; D044383:Black People; D001794:Blood Pressure / Q000502:physiology*; D018660:Blood Pressure Monitoring, Ambulatory; D015992:Body Mass Index; D002940:Circadian Rhythm; D004452:Echocardiography; D005260:Female; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D017379:Hypertrophy, Left Ventricular / Q000000981:diagnostic imaging / Q000208:ethnology*; D008297:Male; D008875:Middle Aged; D014481:United States; D014655:Vascular Resistance / Q000502:physiology*; D044465:White People; D001741:Black or African American