LEFT-VENTRICULAR HYPERTROPHY AND AMBULATORY BLOOD-PRESSURE

The relationship between ambulatory blood pressure and degree of left ventricular hypertrophy is analysed with a triple objective: - to assess the value of ambulatory blood pressure recording; the observation of better correlations between left ventricular mass (LVM) and systolic BP with ambulatory rather than clinical recordings is one of the most convincing arguments in favour of the prognostic value of this technique; - to guide analysis of ambulatory blood pressure recordings. These recordings provide a large number of measurements over a period of variable duration. The selection of the frequency of measurement, the duration of the recording and the periods of recording (at work, during the day or night), of the criteria of interpretation (average, variability, distribution of values) is partially arbitrary. The possibility of predicting the degree of LVH from these results is one of the only rational approaches while awaiting validation with respect to long-term outcome. In the author's experience, the average of the systolic blood pressure values during the period of activity is the parameter which is most closely related to LVM in untreated hypertensive patients; - to improve our understanding of the relationship between the blood pressure, LVM and left ventricular function. There is evidence that the LVH of hypertensive patients has a multifactorial basis. The use of only occasional blood pressure measurements in clinical studies may have increased the apparent importance of one or another factor related to the degree of LVH. The precise influence of these factors, independant of their possible relationship to the blood pressure, should now be reevaluated with respect to ambulatory blood pressure recordings. In addition, the consequences of variations in blood pressure on cardiac morphology and function can also be studied. The persistance of raised blood pressure at night, especially with antihypertensive therapy, may play a role in sustaining LVH. Increased variability of blood pressure values may also be an aetiological factor of LVH: this can only be evaluated by continuous ambulatory blood pressure recordings as the non-invasive discontinuous method is unsuitable for testing this hypothesis. Finally, ambulatory blood pressure recordings could be the best way of evaluating the effects of changes in blood pressure after treatment on cardiac parameters.