Blood Pressure, Heart Rate, Cardiovascular Reflexes and Electrocardiographic changes in some Hypertensive Nigerians

The effects of hypertension on resting and reflex cardiovascular function were investigated in this study. Blood pressure, heart rate and electrocardiogram were recorded in male and female control subjects and hypertensive Nigerian patients. Blood pressure was measured, using the sphygmomanometer/auscultatory method. Heart rate was determined from palpating the radial pulse or from the resting electrocardiograph. The systolic and diastolic blood pressures were high in the hypertensive patient (160.90 ± 2.06 mmHg and 110.8 ± 1.95 mmHg respectively compared with control subjects (119.3 ± 2.05 and 73.58 ± 1.09mmHg; P<0.01). Pulse pressure and mean arterial pressures were also higher in the hypertensive patients. Heart rate was higher in the hypertensive compared to the control groups (86.93 ±+ 2.83 cf 71 ± 1.35 beats per minute, P<0.01). ECG analysis showed that the intervals were lower in the controls than in the hypertensive group except for PR intervals (0.21 ± 0.01 cf 0.23 ± 0.01 sec). The amplitude of the waves was also lower in the control group than the hypertensive group. Cardiovascular response to exercise assessed from the post-exercise recovery graph showed that the aggregate recovery (6min after) was lower in the hypertensive subjects (22% cf 28%, p<0.05) than in controls. This suggests that the baroreflex sensitivity was higher in the control than in the hypertensive subjects. Results from this study suggest that in hypertension there may be increased heart rate, altered electrocardiograph readings indicating ventricular hypertrophy and delay in ventricular conduction. In hypertension baroreflex sensitivity may be reduced.

Keywords
Blood pressure; Heart Rate; ECG; Cardiovascular reflexes; Hypertension; Nigerian