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Relationship between ambulatory or exercise blood pressure and left ventricular structure: prognostic implications
1Department of Medicine, New York Hospital-Cornell Medical Center, New York 10021.
Insights
Left ventricular mass, measured by echocardiography, is a key predictor of cardiovascular events. Blood pressure during activity, not clinic readings, better reflects this cardiac measure.
Area of Science:
- Cardiology
- Cardiovascular Physiology
- Diagnostic Imaging
Background:
- Left ventricular mass (LVM) is a critical indicator of cardiac health.
- LVM measured by echocardiography predicts cardiovascular events better than most risk factors, excluding age.
- Blood pressure (BP) monitoring methods influence their correlation with LVM.
Purpose of the Study:
- To evaluate the relationship between different blood pressure measurement techniques and left ventricular mass.
- To determine if activity-based BP measurements correlate better with LVM than casual BP readings.
- To explore the prognostic significance of LVM in cardiovascular risk assessment.
Main Methods:
- Echocardiography for accurate measurement of left ventricular mass.
- Ambulatory blood pressure monitoring (24-hour and daytime periods).
- Blood pressure assessment during maximal or submaximal exercise.
Main Results:
- Studies consistently show a stronger correlation between LVM and ambulatory BP compared to casual BP measurements.
- Blood pressure readings taken during physical or mental activity correlate better with LVM than clinic-based measurements.
- This suggests activity-related BP is a more sensitive indicator of cardiac structure.
Conclusions:
- Echocardiographic LVM serves as a valuable 'bioassay' for assessing the heart's response to BP.
- Activity-related BP measurements provide a more accurate reflection of cardiovascular structure than standard clinic readings.
- Further research into the mechanisms linking activity-induced BP and cardiac hypertrophy is warranted.
Abstract:
Left ventricular mass can be accurately measured by echocardiography, and this measurement has been shown to be a stronger predictor of cardiovascular morbid events or of death than blood pressure levels or all other conventional risk factors except age. Echocardiographic left ventricular mass is thus a useful 'bioassay' that can determine the effects on the heart of various measures of blood pressure. All available studies have shown a closer relationship between left ventricular mass or left ventricular wall thickness and blood pressure as measured by ambulatory monitoring over 24 h or during specific time periods, such as the working day, compared with casual pressure measurements. Similarly, blood pressure at the end of maximal or submaximal exercise predicted left ventricular mass better than causal pressures in each study of this topic. Thus there is a closer parallel between prognostically important measures of left ventricular structure and blood pressure during physical or mental activity than with clinic measurements of blood pressure. Although the mechanisms underlying these relationships are not fully understood, it has been proposed that the blood pressure levels measured during activity may be more closely related to left ventricular structure than conventional clinic measurements, that these levels appear to be free from any alerting reaction to the physician taking the measurement and that there may be a fundamental biological link between the stimuli to blood pressure levels during activity and cardiovascular hypertrophy.