Researchers Call for Earlier Monitoring of Cardiac Function Among High-risk Patients

An analysis of 30-year data on participants from the longitudinal Augusta Heart study shows that Black individuals begin to exhibit potential signs of congestive heart failure earlier than their White counterparts, according to findings published in Journal of the American Heart Association.

This disparity can begin to appear as early as adolescence and encompasses a decrease in heart muscle strength and an increase in blood pressure.

Midwall fractional shortening (MFS) was used to gauge the heart’s ability to contract because of its apparent ability “to provide earlier insight that the heart wall is beginning to thicken and weaken in response to pushing against higher pressure inside the aorta, the body's largest blood vessel, which delivers oxygen-rich blood to the body,” compared with ejection fraction.

“Starting with early childhood, otherwise healthy Black people show signs of slightly diminished heart muscle strength and a slightly higher blood pressure than their white counterparts, factors which may put them on a course for early development of congestive heart failure,” said the authors in a statement.

Their analysis covered 673 health participants, followed at the Georgia Prevention Institute, and 4596 observations. Most of the patients were female (50.4%), 52.3% were of White ancestry, and 47.7% were of Black ancestry. Mean (SD) ages were close to equal in the White and Black patient groups, at 15.4 (3.0) and 15.1 (3.33) years, respectively (P = .2083).

“To the best of our knowledge, this prospective study is the first to examine the life span changes of myocardial function in a healthy cohort,” the authors said. “We report changes in the MFS over time, with significant differences between Black and White participants.”

Compared with White participants, Black participants had higher mean (SD) measures of the following at their initial study visit:

• Weight: 68.6 (22.5) vs 61.2 (20.4) kg (P < .0001)
• Body mass index (BMI): 25.0 (7.2) vs 22.6 (5.8) kg/m² (P < .0001)
• Systolic blood pressure (SBP): 111.3 (10.7) vs 107.8 (8.8) mm Hg (P < .0001)
• Diastolic blood pressure (DBP): 59.5 (7.1) vs 57.2 (5.9) mm Hg (P < .0001)
• Total peripheral resistance (TPR): 16.2 (3.9) vs 14.7 (3.8) mm Hg (P < .0001)
• Left ventricular mass (LVM): 127.6 (35.8) vs 118.8 (37.7) g (P = .0013)

They also initiated the study with a lower MFS, at 97.4 (11.6) vs 98.2 (12.6).

Analysis also showed the male participants started the study with these higher measures:

• Height: 167.0 (13.0) vs 160.5 (8.6) cm (P < .0001)
• SBP: 111.7 (10.3) vs 107.3 (8.9) mm Hg (P < .0001)
• TPR: 15.8 (4.1) vs 15.1 (3.6) mm Hg (P = .0067)
• Circumferential end-systolic stress (cESS): 141.8 (30.1) vs 133.3 (29.7) 10³dyne/cm² (P = .0002)
• LVM: 133.4 (39.5) vs 112.9 (31.3) g (P < .0001)
• MFS: 99.3 (12.0) vs 96.4 (12.1) (P = .0022)

The male participants also initiated the study with lower BMI (23.1 [5.6] vs 24.4 [7.4] kg/m²; P = .0164) and DBP (57.6 [6.3] vs 59.0 [6.7] mm Hg; P = .0120).

MFS was also shown to be lower among the Black participants compared with the White participants, despite the tendency for it to increase with age among both groups, the authors noted. Over the course of the study among the Black patients, MFS decreased by 0.54%.

The measure additionally was shown to be adversely affected by LVM and cESS:

• For every 1-g increase in LVM, MFS decreased by 0.02%.
• For each 1-unit increase in cESS, MFS decreased by 0.04%.

A potential reason for the MFS differences among the participants is the increased blood pressure burden frequently seen among Black individuals precipitated by their higher rates of stress-induced sodium retention compared with White individuals. The authors also highlight that “genetic factors rather than afterload or cardiac mass may contribute to myocardial function depression.”

They believe their findings have merit, noting, “Our findings support an important role of cardiac load on myocardial function trajectories from childhood to early adulthood. Black participants showed a decreased myocardial performance when compared with White participants. With afterload being the central driver of myocardial performance during normal aging, we thus identify one possible mechanism that may explain how cardiac performance may deteriorate in time in populations with high cardiovascular risk.”

The main study strength is that the multiethnic cohort well represents a population known to be at high risk of developing cardiovascular disease (inhabitants of the southeastern United States), and the principal limit to wider generalization is that the study’s longitudinal basis lends itself to long-term attrition.

Reference

Kapuku G, Howie M, Ghosh S, et al. Effects of race, cardiac mass, and cardiac load on myocardial function trajectories from childhood to young adulthood: the Augusta Heart study. J Am Heart Assoc. Published online January 18, 2021. doi:10.1161/JAHA.119.015612