In normal cases, nocturnal
blood pressure (BP) falls between 10–20%, compared with
daytime BP (BP dipper pattern).The non-dipping pattern of ambulatory BP is associated with secondary hypertension and target organ damage. Our aim was to investigate the difference of heart rate between non-dippers and dippers.
Methods
BP variability can be estimated as a standard deviation of ambulatory BP monitoring obtained by every 15–20 min measurement. The ambulatory BP and HR were monitored every 20 min with a fully automatic device. Ambulatory BP monitoring were performed in 124 patients in the University hospital Ibn Rochd in Casablanca. We measured the blood pressure and heart rate parameters. The criteria of non-dipping pattern was diurnal index, 10%.
Results
Non-dipping pattern was found in 41 cases and dipping pattern was found in 83 cases. The 24h systolic blood pressure in non-dipping group (NDG) was 133.92±16.89 mmHg, in the dipping group (DG) was 127.49±13.81 mmHg (p= 0.005) and the diastolic was 75.38±12.81 mmHg (NDG) and 75.67±11.91 mmHg (DG) (p= 0.08). The heart rate was lower in the NDG than in the DG: 69.65±9.81 vs 70.59±9.48 bpm (p= 0.02).
Conclusion
In NDG, we found lower heart rate. Presumably reflecting altered function of the sympathetic nervous system, the baroreceptor oscillations are shifted to lower frequencies. It is clear that more work should be carried out to evaluate the impact of heart rate variability on non dipper patients.
The author hereby declares no conflict of interest
