Heart rate variability on antihypertensive drugs in black patients living in sub-Saharan Africa.
BACKGROUND
Compared with Caucasians, African Americans have lower heart rate variability (HRV) in the high-frequency domain, but there are no studies in blacks born and living in Africa.


METHODS
In the Newer versus Older Antihypertensive agents in African Hypertensive patients trial (NCT01030458), patients (30-69 years) with uncomplicated hypertension (140-179/90-109 mmHg) were randomized to single-pill combinations of bisoprolol/hydrochlorothiazide (R) or amlodipine/valsartan (E). 72 R and 84 E patients underwent 5-min ECG recordings at randomization and 8, 16 and 24 weeks. HRV was determined by fast Fourier transform and autoregressive modelling.


RESULTS
Heart rate decreased by 9.5 beats/min in R patients with no change in E patients (- 2.2 beats/min). R patients had reduced total (- 0.13 ms²; p = 0.0038) and low-frequency power (- 3.6 nu; p = 0.057), higher high-frequency (+ 3.3 nu; p = 0.050) and a reduced low- to high-frequency ratio (- 0.08; p = 0.040). With adjustment for heart rate, these differences disappeared, except for the reduced low-frequency power in the R group (- 4.67 nu; p = 0.02). Analyses confined to 39 R and 47 E patients with HRV measurements at all visits or based on autoregressive modelling were confirmatory.


CONCLUSIONS
In native black African patients, antihypertensive drugs modulate HRV, an index of autonomous nervous tone. However, these effects were mediated by changes in heart rate except for low-frequency variability, which was reduced on beta blockade independent of heart rate.
Studies Coordinating Centre, Research Unit Hypertension and Cardiovascular Epidemiology, KU Leuven Department of Cardiovascular Sciences, University of Leuven , Belgium.
Chukwunomso E
CE
Osakwe
Lotte
L
Jacobs
Benedict C
BC
Anisiuba
Mouhamado B
MB
Ndiaye
Daniel
D
Lemogoum
Chinwuba K
CK
Ijoma
Marius M
MM
Kamdem
Lutgarde
L
Thijs
Hilaire J
HJ
Boombhi
Joseph
J
Kaptue
Philip M
PM
Kolo
Jean B
JB
Mipinda
Augustine N
AN
Odili
Birinus
B
Ezeala-Adikaibe
Samuel
S
Kingue
Babatunde A
BA
Omotoso
Serigne A
SA
Ba
Ifeoma I
II
Ulasi
Jean-Rene
JR
M'buyamba-Kabangu
Jan A
JA
Staessen
D017954:Africa South of the Sahara; D000959:Antihypertensive Agents / Q000627:therapeutic use*; D015331:Cohort Studies; D005260:Female; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D006973:Hypertension / Q000188:drug therapy* / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged
D000959:Antihypertensive Agents
Antihypertensive drugs; blacks; heart rate variability; randomized clinical trial; sub-Saharan Africa