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Plasma norepinephrine and left ventricular hypertrophy in systemic hypertension
Insights
Norepinephrine (NE) levels are linked to left ventricular (LV) hypertrophy in hypertensive patients with elevated NE. Mean blood pressure is key in those with normal NE levels.
Area of Science:
- Cardiology
- Hypertension Research
- Clinical Investigation
Background:
- Essential hypertension frequently leads to left ventricular (LV) hypertrophy.
- Understanding the factors influencing LV hypertrophy is crucial for managing hypertensive heart disease.
Purpose of the Study:
- To investigate the relationship between pressure and humoral factors with echocardiographic indices of LV hypertrophy in essential hypertension.
- To identify specific factors associated with LV hypertrophy in different patient subgroups.
Main Methods:
- Studied 64 patients with essential hypertension, assessing echocardiographic LV mass and circulating factors.
- Utilized multivariate stepwise regression analysis to determine significant relationships.
- Subgroup analysis was performed based on plasma norepinephrine (NE) levels.
Main Results:
- 57% of patients exhibited LV hypertrophy.
- Mean blood pressure (BP) and norepinephrine (NE) were related to LV mass index in patients with LV hypertrophy.
- NE was significantly correlated with LV mass index only in patients with abnormally elevated NE levels (r=0.89, p<0.01).
- Diastolic BP was the primary factor related to LV mass index in hypertensive patients without LV hypertrophy.
Conclusions:
- Norepinephrine may play a role in regulating LV hypertrophy development, particularly in hypertensive patients with elevated circulating NE levels.
- Blood pressure remains a critical factor in LV hypertrophy, irrespective of NE levels.
- Further research is needed to elucidate the specific mechanisms linking NE to cardiac remodeling in hypertension.
Abstract:
The relations between some pressure and humoral factors, and some echocardiographic indexes of left ventricular (LV) hypertrophy were studied in 64 patients with essential hypertension. Fifty-seven percent of these patients showed echocardiographic evidence of LV hypertrophy (LV mass greater than 215 g). Multivariate stepwise regression analysis showed that only mean blood pressure (BP) and circulating norepinephrine (NE) levels were significantly related to LV mass index in the group of patients with LV hypertrophy. However, mean BP was the only factor related to LV mass index in the subgroup of patients with LV hypertrophy and plasma NE within the normal laboratory range, whereas NE was the sole factor related to LV mass index in the subgroup with LV hypertrophy and abnormally elevated NE levels (greater than mean + 2 standard deviations of the normal laboratory range). Correlation of LV mass index vs NE was -0.35 (not significant) in the former group of patients and 0.89 (p less than 0.01) in the latter group. NE showed no relation with the echocardiographic variables in the hypertensive patients without LV hypertrophy; in this group, diastolic BP was the only factor related to LV mass index. Circulating NE levels were slightly higher in patients with LV hypertrophy (213 +/- 68 ng/liter) than in those without LV hypertrophy (187 +/- 46 ng/liter), but differences were not significant when adjusting NE for age. Plasma renin activity was not dissimilar in the absence or presence of hypertrophy. In conclusion, our findings suggest that NE might be associated with pressure factors in regulating LV hypertrophy development only in a subgroup of hypertensive patients characterized by echocardiographic LV hypertrophy and abnormally elevated circulating NE levels.