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Relationship between left ventricular mass and hemodynamic responses to physical and mental stress
W J Kop1, J S Gottdiener, S M Patterson
1Department of Medical and Clinical Psychology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA. wjkop@mxb.usuhs.mil
Insights
Systolic blood pressure responses to mental stress predict increased left ventricular mass (LVM) in healthy individuals. These hemodynamic responses may offer insights into cardiac damage development.
Area of Science:
- Cardiology
- Hypertension Research
- Physiology
Background:
- Increased left ventricular mass (LVM) is a key predictor of cardiovascular events.
- While casual and ambulatory blood pressure (BP) are known predictors of LVM, other hemodynamic factors remain less understood.
Purpose of the Study:
- To investigate laboratory-induced hemodynamic responses to exercise, cold, and mental stress as predictors of LVM.
- To compare these responses with 24-hour ambulatory BP measures in predicting LVM.
Main Methods:
- Thirty-six healthy non-hypertensive subjects underwent laboratory stress tests (mental, cold, exercise) and 24-hour ambulatory BP monitoring.
- Left ventricular mass (LVM) was assessed using echocardiography and indexed for body surface area (LVMI).
Main Results:
- Systolic blood pressure (SBP) responses to mental stress and cold pressor tests were significantly related to LVM.
- Mental stress-induced SBP response was the sole significant predictor of LVMI after adjusting for body size.
- Exercise SBP response was associated with LVMI in men but not in women.
Conclusions:
- SBP responses to mental stress significantly predict LVM in healthy individuals, independent of baseline BP, ambulatory BP, age, body size, and sex.
- Hemodynamic responses during laboratory tasks may provide crucial information on the pathophysiology of cardiac end-organ damage.
Objective:
Increased left ventricular mass (LVM) is predictive of future cardiac morbidity and mortality. Although casual and ambulatory blood pressure (BP) predict LVM, other hemodynamic determinants of LVM are incompletely understood. The present study examines laboratory-induced hemodynamic responses (to exercise, cold, and mental stress) and 24-hour ambulatory measures as predictors of LVM.
Methods:
Thirty-six healthy non-hypertensive subjects (mean age 33.9 +/- 9.4 years; 23 women, 13 men) were tested with mental stress, cold pressor, and treadmill exercise in the laboratory and 24-hour ambulatory BP monitoring. LVM was measured using two-dimensional targeted M-mode echocardiography and indexed for body surface area (LVMI).
Results:
All laboratory tasks produced significant hemodynamic responses (p's < 0.01). Systolic blood pressure responses to mental stress (r = 0.42, p < 0.01) and cold pressor (r = 0.34, p < 0.05) were significantly related to LVM. After adjusting for body size, the mental stress-induced SBP responses was the only significant predictor of LVMI (r = 0.32, p < 0.05). Exercise SBP responses were associated to LVMI in men (r = 0.63, p = 0.02), but not in women (r = 0.02, p = n.s.). Multivariate regression analyses revealed that SBP during mental stress was significantly predictive of LVMI (beta = 0.65, p = 0.05), independent of baseline SBP, 24-hour ambulatory SBP, and other control variables.
Conclusion:
The present results indicate that SBP responses to mental stress are significantly related to LVM among healthy individuals, independently of baseline SBP, 24-hour ambulatory BP, age, body size, and sex. Blood pressure responses to exercise show a robust association with LVM in men but not in women. Hemodynamic responses elicited during laboratory tasks may therefore reveal important information about the pathophysiological processes involved in the development of cardiac end-organ damage.