Intrafamilial aggregation and heritability of left ventricular geometric remodeling is independent of cardiac mass in families of African ancestry.
BACKGROUND
Whether left ventricular (LV) geometric remodeling, as indexed by relative wall thickness (RWT), aggregates in families and is inherited independent of LV mass (LVM) and additional confounders is uncertain.


METHODS
We determined whether RWT as assessed from 2D targeted M-mode echocardiography shows intrafamilial aggregation and heritability independent of LVM in 181 nuclear families (73 spouse pairs, 403 parent-child pairs, and 177 sibling-sibling pairs) with 16 families including 3 generations from an urban developing community of black Africans. Intrafamilial aggregation and heritability estimates (S.A.G.E. software) were assessed independent of confounders, including central aortic systolic blood pressure (SBPc) (radial applanation tonometry and SphygmoCor software).


RESULTS
Independent of confounders including SBPc, LV RWT was correlated in parent-child (r = 0.32, P < 0.0001) and sibling-sibling (r = 0.29, P < 0.0001), but not in spouse (r = 0.11, P = 0.33) pairs. The relationships between parent-child (r = 0.28, P < 0.0001) and sibling-sibling (r = 0.24, P < 0.001) pairs persisted with further adjustments for LVM or LVM indexed to height(2.7) (LVMI). Similarly, independent of confounders, LV RWT showed significant heritability (h(2) ± SEM = 0.56 ± 0.09, P < 0.0001) and this persisted with further adjustments for LVM (h(2) ± SEM = 0.48 ± 0.09, P < 0.0001) or LVMI (h(2) ± SEM = 0.49 ± 0.09, P < 0.0001).


CONCLUSIONS
In a group of African ancestry, independent of LVM, LV geometric remodeling shows significant intrafamilial aggregation and heritability. Genetic factors may in-part determine the LV geometric remodeling process independent of the extent of cardiac hypertrophy.
Cardiovascular Pathophysiology and Genomics Research Unit, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa;
Vernice R
VR
Peterson
Cardiovascular Pathophysiology and Genomics Research Unit, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa;
Gavin R
GR
Norton
Cardiovascular Pathophysiology and Genomics Research Unit, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa;
Michelle
M
Redelinghuys
School of Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
Carlos D
CD
Libhaber
Cardiovascular Pathophysiology and Genomics Research Unit, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa;
Muzi J
MJ
Maseko
Cardiovascular Pathophysiology and Genomics Research Unit, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa;
Olebogeng H I
OH
Majane
Cardiovascular Pathophysiology and Genomics Research Unit, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa;
Richard
R
Brooksbank
Cardiovascular Pathophysiology and Genomics Research Unit, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; angela.woodiwiss@wits.ac.za.
Angela J
AJ
Woodiwiss
D000328:Adult; D044383:Black People / Q000235:genetics*; D001794:Blood Pressure / Q000502:physiology*; D018618:Echocardiography, Doppler, Color / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006352:Heart Ventricles / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006801:Humans; D017379:Hypertrophy, Left Ventricular / Q000208:ethnology / Q000235:genetics* / Q000503:physiopathology; D015994:Incidence; D008297:Male; D008875:Middle Aged; D010375:Pedigree; D012189:Retrospective Studies; D013019:South Africa / Q000453:epidemiology; D020257:Ventricular Remodeling / Q000502:physiology*
blood pressure; hypertension; inheritance; intrafamilial aggregation; left ventricular remodeling.