Cardiovascular Journal of Africa: Vol 32 No 6 (NOVEMBER/DECEMBER 2021)

CARDIOVASCULAR JOURNAL OF AFRICA • Volume 32, No 6, November/December 2021 316 AFRICA mean PWD was 37.68 ± 3.07 ms. This difference was statistically significant (Table 1). Table 2 shows the comparison of clinical, ECG and echo parameters among subjects with prolonged and normal PWD. One hundred and five (70%) of the subjects had prolonged PWD while 49 (32.7%) had normal PWD ( p < 0.0001). Mean PWD was significantly longer in subjects with prolonged PWD, compared to those with normal PWD (42.06 ± 6.31 vs 29.52 ± 3.34; p < 0.0001). There was no significant difference in the age distribution of subjects with normal and prolonged PWD. Comparing their clinical parameters, such as mean SBP, DBP, BMI, WC and duration of hypertension in months, only the mean WC of the subjects increased significantly with prolonged PWD. Among subjects with prolonged PWD, 25 (24%) had LVH on ECG by Sokolow–Lyon criteria, compared to 15 (34.1%) subjects with normal PWD. This difference was not significant ( p = 0.21). Again, the mean left atrial diameter (LAD) and LVMI were slightly higher in subjects with prolonged PWD compared to those with normal PWD, but not statistically significant. Table 3 shows the correlation of PWD with LVMI, and left ventricular systolic and diastolic function among the hypertensive subjects. There was no correlation between the mean PWD and mean LVMI among hypertensives ( r = 0.08, p = 0.33), although a negative correlation existed between mean PWD and EF ( r = –0.17, p = 0.03) and a significant almost linear relationship between PWD and WC ( r = 0.23, p = 0.004). Other associations are shown in Table 3. A Pearson’s correlation was also done between ECG LVH and LVMI in the subjects and a weak but significant association was found ( r = 0.20, p = 0.02). Discussion In this study, mean PWD of the healthy subjects was 32.11 ± 4.72 ms, which is slightly shorter than in a large community study by Gialafos et al ., 21 where they found mean PWD of 38.4 ms (range 13–80). The difference in demographics of the population studied may account for this since theirs were healthy young air-force servicemen. In this study, the mean PWD was significantly longer in the subjects than in the controls. This finding is similar to that observed among hypertensives by Dagil et al ., 9 where the mean PWD among hypertensives was also longer (56.1 ± 5.8 ms) compared to their controls (30.3 ± 6.6 ms), with a similar mean age distribution of 49 ± 10.6 years. This corroborates what is documented in the literature. 11,17,22-26 This study also showed that P max duration was significantly longer in the subjects than in the controls, which is in agreement with findings by Dagil et al. 9 However the mean P max duration in this present study was longer than that reported by Dagil et al . This difference is largely methodological; Dagil et al . used a cut-off point of ≥ 110 ms while ≥ 120 ms was used here. Ariyarajah et al . 16 recommended > 120 ms as the cut-off point, Table 1. Comparison of demographic, clinical, ECG and echocardiographic parameters in hypertensive subjects and normotensives controls Parameter Subjects ( n = 150) Controls ( n = 150) p -value Gender, male 72 (48.00) 76(50.60) 0.64 Age (years) 49.38 ± 11.31 47.14 ± 11.72 0.09 BMI (kg/m 2 ) 26.84 ± 3.64 25.32 ± 3.22 < 0.001* WC (cm) 95.74 ± 11.08 92.24 ± 9.62 0.004* DBP (mmHg) 90 ± 12.22 74.37 ± 9.08 < 0.001* SBP (mmHg) 139.38 ± 17.19 118.52 ± 12.5 < 0.001* PWD (ms) 38.29 ± 8.02 32.11 ± 4.72 < 0.001* P max duration (ms) 114.62 ± 16.28 107.16 ± 15.5 < 0.001* P min duration (ms) 82.31 ± 14.87 76.96 ± 14.40 < 0.001* Mean of prolonged PWD (ms) 42.06 ± 6.31 37.68 ± 3.07 0.003* Mean of normal PWD (ms) 29.52 ± 3.34 29.41 ± 2.46 < 0.001* Prolonged PWD 105 (70.00) 49 (32.70) < 0.001* Prolonged P max 46 (30.70) 29 (19.30) < 0.001* LVH by echo 47 (31.30) 25 (16.70) 0.003* Mean LVMI (g/m 2.7 ) 42.04 ± 15.55 34.24 ± 10.01 < 0.001* E/A 1.16 ± 0.42 1.28 ± 0.36 0.01* Septal e ′ 8.97 ± 2.64 10.53 ± 2.63 < 0.001* E/e ′ 8.59 ± 3.07 7.72 ± 2.09 0.007* Values are expressed as mean ± SD or n (%). BMI, body mass index; WC, waist circumference; DBP, diastolic blood pressure; SBP, systolic blood pressure; PWD, P-wave dispersion; LVH, left ventricular hypertrophy, LVMI, left ventricular mass index. Table 2. Comparison of clinical, ECG and echo parameters of subjects with prolonged and normal PWD Parameter Prolonged PWD ( n = 105) Normal PWD ( n = 45) Age distribution (years) 18–30 6 (5.70) 3 (6.70) 31–40 13 (12.40) 9 (20.00) 41–50 36 (34.30) 12 (26.70) 51–60 36 (34.30) 13 (28.90) ≥ 61 14 (13.30) 8 (17.80) 0.63 Mean SBP (mmHg) 139.11 ± 17.73 139.87 ± 16.73 0.81 Mean DBP (mmHg) 89.97 ± 12.41 90.41 ± 11.90 0.14 HTN duration 67.63 ± 7.40 46.58 ± 8.34 0.08 BMI (kg/m 2 ) 27.13 ± 3.47 26.16 ± 3.99 0.14 WC (cm) 96.16 ± 11.14 92.88 ± 10.55 0.04* Mean PWD 42.06 ± 6.31 29.52 ± 3.34 < 0.001* LAD (cm) 3.60 ± 0.46 3.54 ± 0.45 0.59 LVMI 42.451 ± 15.90 41.09 ± 14.83 0.63 EF 67.93 ± 9.14 70.75 ± 8.75 0.08 E/e ′ 7.69 ± 2.04 7.79 ± 2.26 0.79 ECG LVH Sokolow–Lyon 25 (24.00) 15 (34.10) 0.21 Echo LVH 35 (33.30) 12 (26.70) 0.42 EF preserved 104 (99.05) 43 (95.56) EF reduced 1 (0.95) 2 (4.44) 0.49 Values are expressed as mean ± SD or n (%). PWD, P-wave dispersion; SBP, systolic blood pressure; DBP, diastolic blood pressure; HTN, hypertension; BMI, body mass index; WC, waist circumference; LAD, left atrial diameter; LVMI, left ventricular mass index; EF, ejection frac- tion; LVH, left ventricular hypertrophy; LVSF, left ventricular systolic function; preserved is ≥ 50%; reduced is < 50%. Table 3. Correlation of PWD with specific parameters Parameters r p- value SBP –0.01 0.88 DBP 0.07 0.39 LVH (ECG) –0.04 0.64 LVMI 0.08 0.33 E/E ′ 0.02 0.79 EF –0.17 0.03* WC 0.23 0.004* BMI 0.10 0.21 r , Pearson correlation test; *significant p- value. SBP, systolic blood pressure; DBP, diastolic blood pressure; LVH, left ventricu- lar hypertrophy; LVMI, left ventricular mass index; EF, ejection fraction; WC, waist circumference; BMI, body mass index