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Determinants of left ventricular mass in early hypertension
B Baker1, B O'Kelly, J P Szalai
1The Toronto Hospital, University of Toronto, Ontario, Canada.
Insights
Mild hypertension and stress do not impact left ventricular mass (LVM). However, ambulatory blood pressure levels significantly influence the relationship between LVM and relative wall thickness (RWT).
Area of Science:
- Cardiology
- Hypertension Research
- Echocardiography
Background:
- Mildly hypertensive individuals often have normal left ventricular mass (LVM) and relative wall thickness (RWT).
- Psychosocial stressors like marital distress and job strain are potential contributors to cardiovascular changes.
Purpose of the Study:
- To investigate the relationship between psychosocial stress, ambulatory blood pressure, and cardiac structural parameters (LVM, RWT) in unmedicated mildly hypertensive subjects.
- To determine the optimal method for indexing LVM in this population.
Main Methods:
- M-mode echocardiography for LVM and RWT assessment.
- 24-hour ambulatory blood pressure monitoring.
- Standardized questionnaires for marital and job stress evaluation.
Main Results:
- Neither marital distress nor job strain significantly determined LVM.
- Inflection points in ambulatory blood pressure (systolic 131 mmHg, diastolic 83-87 mmHg) were identified in the LVM-RWT relationship.
- Indexing LVM by height provided a better explanation for LVM variability than indexing by body surface area.
Conclusions:
- Psychosocial stress is not a primary determinant of left ventricular mass in mild hypertension.
- Ambulatory blood pressure, particularly specific systolic and diastolic thresholds, plays a crucial role in cardiac remodeling.
- Height-based indexing is recommended for LVM assessment in mildly hypertensive individuals.
Abstract:
One hundred seventy-six unmedicated mildly hypertensive subjects (113 men, 63 women) underwent M-mode echocardiography to determine left ventricular mass (LVM) and relative wall thickness (RWT), 24-h ambulatory blood pressure monitoring, and completed standardized questionnaires measuring marital and job stress. Subjects were aged 46 +/- 9 years old; 45.4% had daytime diastolic blood pressure < 90 mm Hg; 96.1% of LVM results were in the normal range. We found that neither marital distress nor job strain was a determinant of LVM. However, a segmental regression approach revealed inflection points of 131 mm Hg systolic daytime blood pressure and 83 and 87 mm Hg nighttime diastolic blood pressure in the relation between LVM and RWT, respectively, and ambulatory BP. In addition, we found that the variability of LVM was best explained by indexing LVM by height, rather than body surface area.