In the natural history of hypertension, abnormalities of the diastolic performance of the left ventricle are an early manifestation of cardiac involvement, often preceding the development of left ventricular hypertrophy. Previous studies have shown that only some classes of antihypertensive agents are able to reduce left ventricular mass, control of high blood pressure being equal. It has not yet been established if blood pressure control leads to an improvement in left ventricular filling or if, also in this case, the improvement is related to the kind of antihypertensive drug used.
The few studies investigating this issue have provided conflicting results with diuretic, p-blocking, and calcium channel-blocking drugs. It has been suggested that only subjects in whom treatment reduces the left ventricular mass show a consistent reversal of left ventricular filling abnormalities. More recent studies suggest that in untreated early essential hypertension, abnormal left ventricular filling is related to the level of blood pressure and not to the left ventricular mass. The present study was undertaken to determine the effect of an o^-blocking agent (prazosin) in untreated mild to moderate hypertension to assess whether this class of drugs is able to improve left ventricular diastolic filling lowering pressure overload.