Cardiovascular Journal of Africa: Vol 31 No 1 (January/February 2020)

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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 31, No 1, January/February 2020 AFRICA 43
moderate LA enlargement was 42–48 ml/m2, and severe LA
enlargement was > 48 ml/m2.14
LVH was defined as left ventricular mass index > 114 g/m2
in men and > 99 g/m2 in women.14 Ventricular remodelling was
defined based on the relative wall thickness (RWT) and LVM;
concentric remodelling was increased RWT and LVM, eccentric
remodelling was decreased RWT and normal LVM. Diastolic
dysfunction (impaired relaxation) was defined as an E/A ratio
< 1 and deceleration time > 220 ms.14
ECG criteria for determining LVH was defined by the
Sokolow–Lyon index: the sum of the largest R wave of the
V5 or V6 derivation with wave S of the V1 ≥ 3.5 mV (35 mm)
and/or R wave in aVL ≥ 1.1 mV (11 mm). ECG criteria for LA
hypertrophy included: P-wave duration in lead I, II or III > 110
ms; P-wave notching in lead I, II or III with inter-peak duration
> 40 ms (P mitrale); any current or former smokers; impaired
fasting glucose level of 100–125 mg/dl (5.55–6.94 mmol/l); an
abnormal high-density lipoprotein cholesterol < 40 mg/dl (1.04
mmol/l), low-density lipoprotein cholesterol > 110 mg/dl (2.85
mmol/l) and total cholesterol ≥ 200 mg/dl (5.18 mmol/l).
Statistical analysis
Data were analysed using the Statistical Package for Social
Sciences version 23 (IBM SPSS, Atlanta). Data are expressed as
mean ± standard deviation (SD) or as median and interquartile
range (IQR) where appropriate. Medians were compared using
the Mann–Whitney U-test.
Pearson’s correlation was used to assess the individual
relationship between LA size with age, body mass index
(BMI), SBP, DBP, pulse pressure, LVM, LVH and other
echocardiographic parameters. Variables that had significant
associations on bivariate analysis were tested in a step-wise linear
regression model and adjusted for age and gender.
Results
A total of 52 patients were enrolled along with 40 control
subjects. The median age was 49 years. The age ranged between
33 and 75 years with a similar male-to-female ratio between the
two groups. There was a significant difference in blood pressure
variables (SBP, DBP, mean atrial pressure and pulse pressure)
between the two groups. Table 1 shows the clinical characteristics
of patients.
The median duration of hypertension was one month and
15% of the patients were not yet treated. Monotherapy with
calcium channel blocker (34.6%), followed by combination
therapy of thiazide diuretic and angiotensin converting enzyme
inhibitors (13.4%) were the most frequently used medication.
Table 2 shows characteristics specific to the hypertensive patients.
The LV mass was significantly higher in hypertensive
patients compared to the control group. Similarly, the diastolic
function assessed by the E/A ratio was significantly impaired in
hypertensive patients. These findings are shown in Table 3.
The LA longitudinal diameter (p = 0.045), surface area (p =
0.003) and biplane volume (p = 0.002) were significantly higher
in the patients with hypertension. Table 4 shows the difference in
LA sizes between hypertensive patients and controls.
LA structural changes, defined by LA enlargement, was
found in 14 (26.9%) hypertensive patients versus one (2.5%)
control individual (p < 0.0001). Among these patients, 64.3%
had mild LA enlargement, 21.4% moderate and 14.3% severe LA
enlargement, as shown in Figs 3 and 4.
On univariate analysis the following factors were tested for
relationship with LA volume: age, gender, systolic and diastolic
blood pressures, BMI, LV wall thickness [left ventricular
end-systolic diameter (LVESD), interventricular septal diameter
at diastole (IVSD), posterior wall diameter at diastole (PWDD)],
LVM, and diastolic function (E/A, E/E′). Significant correlations
were found with BMI (r = 0.30; p = 0.004), DBP (r = –0.30; p =
0.02), LVEDD (r = 0.367; p = 0.009) and E/A ( r = 0.368; p =
0.009) among the hypertensive patients (See Table 5).
Variables with significant correlation and a p-value < 0.05
were entered in a step-wise multiple linear regression model and
adjusted for age and gender. Diastolic function (E/A < 1) was
the only independent predictor of LA volume in hypertensive
patients (p = 0.006). This is shown in Table 6.
Discussion
Our study showed that there was a significant increase in the
LA longitudinal diameter, surface area and volume among
Table 1. Clinical characteristics of the study population
Variable
Hypertensives
(n = 52)
Controls
(n = 40) p-value
Age (years) 49.0 (43.2–59.7) 49.0 (43.0–57.7) 0.93
Male, n (%) 22 (42.3) 18 (45) 0.834+
BMI (kg/m2 ) 29.2 (26.9–32.4) 27.7 (24.6–31.0) 0.04
SBP (mmHg) 150.0 (142.0–159.0) 125 (115.0–130.0) < 0.0001*
DBP (mmHg) 95.0 (89.0–100.0) 79.0 (68.5–89.0) < 0.0001*
Heart rate (beats/min) 75.5 (69.0–88.7) 75.5 (68.0–82.7) 0.34
Pulse pressure (mmHg) 56.0 (48.2–65.0) 42.0 (35.5–54.0) < 0.0001*
MAP (mmHg) 113.8 (105.7–118.5) 93.8 (87.5–101.0) < 0.0001*
Values are presented as median (interquartile range) or number (%). BMI, body
mass index; SBP, systolic blood pressure; DBP, diastolic blood pressure; MAP,
mean arterial pressure.
+p-value from Fisher’s exact test; *p-value from Mann–Whitney U-test.
Table 2. Characteristics of the hypertensive patients
Variable Number (%) Overall, n
Duration of hypertension (months) 1 (0–6) 52
Alcohol intake 18 (34.6) 52
Former smoker 1 (2) 52
Current smoker 2 (4) 52
Sedentary 32 (61.5) 52
Family history of hypertension 25 (48) 52
ECG LV hypertrophy 8 (15.3) 52
ECG LA hypertrophy 5 (9.6) 52
Elevated LDL-C 5 (19.6) 26
Low HDL-C 7 (26.9) 26
Elevated cholesterol 8 (30.7) 26
Abnormal creatinine 0 (0) 38
Elevated uric acid 2 (12.5) 16
Impaired fasting glucose 2 (5.2) 38
CCB 18 (34.6) 52
ACEI/ARB + thiazides 7 (13.4) 52
Values are presented as median (interquartile range) or number (%). LV, left
ventricular; LA, left atrial; LDL-C, low-density lipoprotein cholesterol; HDL-C,
high-density lipoprotein cholesterol; CCB, calcium channel blocker; ACEI,
angiotensin converting enzyme inhibitor, ARB, aldosterone receptor blocker.