Introduction: This study was designed to address alterations in autonomic nervous system activity in normotensive subjects with a family history of hypertension. We compared the autonomic nervous system activity in 11 normotensives with a family history of hypertension (age 23.3 ± 0.4) and 14 normotensives with no family history of hypertension (age 22.9 ± 0.3).

Methods: In all of the participants their cardiovascular parameters, including impedance cardiography, were measured at rest. In addition, the Valsalva manoeuvre was performed and Valsalva Index was obtained. On the basis of the arterial blood pressure change, provoked by the Valsalva manoeuvre, the latency of baroreflex response was determined.

Results: Normotensives subjects with a family history of hypertension, compared to the control group, showed significantly higher heart rate (75.0 ± 3.4 vs. 62.4 ± 1.8 beats/min), cardiac output (7.6 ± 0.4 vs. 6.7 ± 0.3 L/min), left ventricular weight index (4.6 ± 0.3 vs. 3.9 ± 0.1) and shorter ejection time (298.9 ± 4.9ms vs. 316.8 ± 4.5ms) (t-test, p< 0.05). In addition, the normotensives with a family history of hypertension have decreased latency of the baroreflex response (7.0 ± 0.5 s) compared to the control group (10.5 ± 0.9 s) (p<0.001).

Conclusions: Our results indicate that even normotensives with a family history of hypertension exhibit changes of some cardiovascular parameters at early age. The changes in Valsalva manoeuvre response also show alteration of the autonomic nervous system reactivity.