A number of observations suggest, however, that cardiac autonomic neuropathy (CAN) may also play a role in the development of hypertension. 1 The normal diurnal variability in blood pressure includes a decline in blood pressure during the night and a reduction in heart frequency.
During this procedure it was noticed that introduction of the transesophageal echocardiography (TEE) probe caused a drop in arterial blood pressure (measured invasively in the right radial artery) without a change in heart frequency.
2 CAN affecting vagal nerve function is a frequent and early complication in patients with type 1 diabetes and may play a role in the smaller reduction in heart frequency and thereby the less decline than normal in blood pressure during the night in patients with neuropathy.
The VAN response to this pulse was simulated over a period of Δ T = 100 ms, which corresponds to a heart beat frequency of f = 600 bpm.
Endurance type exercise consisted of interval type exercise on a home trainer, elliptical trainer or rowing ergometer with an average intensity of 73±2%2% of maximum heart frequency.
In patients unable to perform physical exercise or did not reach at least 85% of expected heart frequency maximum (220 beats/min – age) a pharmacological stress with dypyridamole/dobutamine was performed according to a standard protocol (n = 111).
The primary cause of reduced heart frequency and the supposed decline in blood pressure is an increased vagal tone during the night.
For determination of TEE objective methods such as doubly labelled water (DLW) or heart frequency measurements are available.
Outcome parameters were (1) the effects on fetal and maternal heart frequency (FHF / MHF) and blood pressure, and (2) subjective experiences of adverse effects assessed by utilising a questionnaire.
SIRS means two or more of the following symptoms: fever (>38.0 °C or <36.0 °C), white blood cell count (>12 × 109/L or <4 × 109/L), tachypnoea (respiratory rate >20/min or PaCO2 <4.3 kPa), or tachycardia (heart frequency >90 beats per minute).
