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Impact of ethnicity on left ventricular mass and relative wall thickness in essential hypertension
M Zabalgoitia1, S N Ur Rahman, W E Haley
1University of Texas Health Science Center at San Antonio, 78284-7872, USA.
Insights
Ethnicity impacts left ventricular (LV) mass and cardiac adaptation patterns in hypertension. Indexing LV mass to height better represents concentric hypertrophy across ethnic groups.
Area of Science:
- Cardiology
- Hypertension Research
- Population Health
Background:
- Left ventricular (LV) mass and relative wall thickness are key indicators of cardiac adaptation in hypertension.
- Previous studies suggest potential ethnic variations in these parameters, but standardization of measurement remains a challenge.
Purpose of the Study:
- To investigate the influence of ethnicity on LV mass and relative wall thickness in patients with mild to moderate hypertension.
- To compare different indexing methods for LV mass (body surface area, height, height to the power of 2.7) across ethnic groups.
Main Methods:
- A cohort of 527 hypertensive patients (Caucasians, African-Americans, Hispanics) underwent echocardiographic assessment.
- LV mass was indexed using body surface area, height, and height to the allometric power of 2.7.
- Relative wall thickness patterns (normal, concentric remodeling, eccentric hypertrophy, concentric hypertrophy) were analyzed.
Main Results:
- LV mass indexed to body surface area showed no significant ethnic differences.
- Hispanics exhibited slightly larger LV masses when indexed to height and height to the power of 2.7.
- Concentric hypertrophy predominated across all ethnic groups when LV mass was indexed to height or height to the power of 2.7, unlike indexing to body surface area.
Conclusions:
- LV mass indexing to height or height to the power of 2.7 is recommended for population studies due to its independent impact on hypertension.
- Concentric hypertrophy, a response to pressure overload, is more accurately represented by height-based indexing methods than body surface area indexing.
Abstract:
This study was designed to evaluate the impact of ethnicity on left ventricular (LV) mass, and relative wall thickness in 527 patients (57% men, mean age 60 +/- 7 years) with mild to moderate high blood pressure. There were 63% Caucasians, 21% African-Americans, and 16% Hispanics. LV mass was indexed according to body surface area, height, and height to the allometric power of 2.7. Relative wall thickness included the 4 widely recognized patterns: normal, concentric remodeling, eccentric hypertrophy, and concentric hypertrophy. LV mass indexed to body surface area was similar among all 3 ethnic groups (Caucasians 117.1 g/m2, African-Americans 119.2 g/m2, Hispanics 122.7 g/m2); however, when indexed to height and height to the power of 2.7, Hispanics had slightly larger masses than the other 2 groups (Hispanics 168.1 and 73.3 g/m2.7 vs Caucasians 159.8 and 64.4 g/m2.7 [p = NS and p < 0.005]; and vs African-Americans 164.8 and 69.2 g/m2.7 [p = NS for both]). Using body surface area, the concentric remodeling was the predominant form of cardiac adaptation in Caucasians (36%) and African-Americans (42%), whereas the concentric hypertrophy pattern was 38% in Hispanics. Using indexing for both height and height to the power of 2.7, the concentric hypertrophy pattern predominated in all 3 ethnic groups (Caucasians 48% and 51%; African-Americans 68% and 66%; Hispanics 59% and 65%). In conclusion, because of the independent impact of weight on high blood pressure, LV mass adjusted to height or to height at the power of 2.7 should be reported in population studies. The concentric hypertrophy pattern--classic LV response to pressure overload conditions--is better represented when LV mass is indexed to height or to height to the allometric power of 2.7 than to body surface area.