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Classification of hypertrophied hearts in essential hypertension: evaluation by left ventricular wall stress and
Y Sugishita1, K Iida, K Yukisada
1Department of Internal Medicine, University of Tsukuba, Japan.
Insights
Essential hypertension patients with inappropriate hypertrophy show an increased beta-adrenergic response. Those with appropriate hypertrophy have a normal or reduced response, especially with higher noradrenaline levels.
Area of Science:
- Cardiology
- Hypertension Research
- Pharmacology
Background:
- Essential hypertension can lead to left ventricular hypertrophy.
- Cardiac mechanical and non-mechanical indices help assess hypertensive heart disease.
- Beta-adrenergic response is crucial in cardiac function regulation.
Purpose of the Study:
- To investigate cardiac mechanical indices and beta-adrenergic response in essential hypertension patients.
- To differentiate hypertrophy patterns based on end-systolic wall stress.
- To correlate plasma noradrenaline with cardiac function in hypertension.
Main Methods:
- Echocardiography to measure left ventricular mass, fractional shortening, and end-systolic wall stress.
- Isoproterenol infusion to assess the inotropic response (beta-adrenergic function).
- Categorization of patients into groups based on end-systolic wall stress and left ventricular mass.
Main Results:
- Patients with subnormal end-systolic wall stress (inappropriate hypertrophy) had a significantly higher beta-adrenergic response.
- Patients with normal end-systolic wall stress and increased left ventricular mass (appropriate hypertrophy) showed a progressively reduced beta-adrenergic response.
- Higher plasma noradrenaline concentrations were observed in patients with considerably increased left ventricular mass and normal end-systolic wall stress.
Conclusions:
- Inappropriate hypertensive hypertrophy is associated with an increased beta-adrenergic response.
- Appropriate hypertensive hypertrophy shows a normal or diminished beta-adrenergic response, inversely related to plasma noradrenaline.
- Echocardiographic indices and isoproterenol response can characterize different patterns of hypertensive cardiac remodeling.
Abstract:
Left ventricular mass, fractional shortening, and end systolic wall stress (mechanical indices) measured by echocardiography and the response of fractional shortening and end systolic wall stress to the infusion of isoproterenol (0.02 microgram/kg/min for 5 min) (a non-mechanical index) were studied in 57 patients (mean (SD) age 49(8)) with essential hypertension. Nineteen patients had subnormal end systolic wall stress (group 1), 25 patients had normal end systolic wall stress and slightly increased left ventricular mass (group 2A), and 13 patients had normal end systolic wall stress and considerably increased left ventricular mass (group 2B). Plasma noradrenaline concentration was higher in group 2B than in the other groups. When end systolic wall stress was greater than 12 g/cm2 this variable showed a significant inverse linear relation with fractional shortening before isoproterenol infusion. The inotropic response to isoproterenol was measured as the increase of fractional shortening corrected for the decrease of end systolic wall stress (delta fractional shortening/--delta end systolic wall stress). The mean (SD) change in delta fractional shortening/--delta end systolic wall stress was significantly larger in group 1 (1.40 (0.60) cm2/g) than in group 2A (0.85 (0.39) cm2/g), and was significantly larger in group 2A than in group 2B (0.56 (0.15) cm2/g). In patients with hypertensive hypertrophy with subnormal end systolic wall stress (inappropriate hypertrophy) the beta adrenergic response is increased; in hypertensive hypertrophy with normal end systolic wall stress (appropriate hypertrophy), however, it is normal, or becomes reduced as plasma noradrenaline increases.