Marked sympathetic activation and baroreflex dysfunction in true resistant hypertension.

Area of Science:

• Cardiovascular Physiology
• Hypertension Research
• Autonomic Nervous System

Background:

• Essential hypertension is characterized by increased sympathetic drive.
• The role of sympathetic cardiovascular influences in resistant hypertension (RHT) is not fully understood.

Purpose of the Study:

• To investigate sympathetic nervous system activity in patients with resistant hypertension.
• To compare sympathetic activity in RHT patients with treated hypertensives (HT) and normotensive controls (NT).

Main Methods:

• Compared blood pressure, heart rate, and muscle sympathetic nerve traffic (MSNA) in 32 RHT patients, 35 HT patients, and 19 NT individuals.
• Measured spontaneous baroreflex MSNA-sensitivity using microneurography.
• Utilized multiple regression analysis to identify factors related to sympathetic activation.

Main Results:

• RHT patients exhibited significantly higher blood pressure and MSNA compared to HT and NT groups.
• Increased MSNA in RHT was correlated with hemodynamic, hormonal, and metabolic variables.
• Plasma aldosterone and baroreflex sensitivity were closely related to adrenergic activation in RHT.

Conclusions:

• Resistant hypertension is characterized by marked adrenergic overdrive, exceeding that seen in treated hypertension.
• Impaired baroreflex mechanisms, alongside hemodynamic and neurohumoral factors, likely contribute to the adrenergic overdrive in RHT.