Hypertensive left ventricular hypertrophy: relation to peripheral sympathetic drive.

Area of Science:

• Cardiology
• Hypertension Research
• Autonomic Nervous System Studies

Background:

• Left ventricular hypertrophy (LVH) is a significant predictor of morbidity and mortality in hypertension.
• Mechanisms driving LVH are not fully understood but may involve hemodynamic, humoral, and sympathetic nervous system factors.
• The sympathetic nervous system's role in LVH is investigated due to catecholamines' trophic properties.

Purpose of the Study:

• To investigate the association between left ventricular hypertrophy (LVH) and peripheral sympathetic drive in moderate to severe essential hypertension (EHT).
• To test the hypothesis that sympathetic activity, measured by microneurography, differs in hypertensive patients with and without LVH.

Main Methods:

• Studied 28 patients with moderate to severe EHT (JNC-VI stages 2-3), divided into EHT with LVH (n=14) and EHT without LVH (n=14).
• Matched subjects for age, body mass index, and arterial blood pressure.
• Measured peripheral muscle sympathetic nerve activity (MSNA) using microneurography, assessing both multiunit bursts (MSNA) and single-unit vasoconstrictor impulses (s-MSNA) via the peroneal nerve.

Main Results:

• The EHT + LVH group exhibited significantly higher mean s-MSNA frequency (75.9 +/- 6.9 impulses/100 beats) compared to the EHT group (52.1 +/- 2.9 impulses/100 beats; p < 0.001).
• MSNA burst frequency was also greater in the EHT + LVH group (64.2 +/- 5.7 bursts/100 beats) than in the EHT group (48.9 +/- 2.8 bursts/100 beats; p < 0.05).

Conclusions:

• The presence of LVH in moderate to severe hypertension is associated with elevated sympathetic discharge.
• Increased unitary firing frequency and fiber recruitment of sympathetic nerves are evidenced in hypertensive patients with LVH.