Silent ischaemia and hypertension

For many years now, silent ischaemia has been recognized as a distinct clin ical entity, and its relevance in different patient groups has been establi shed. However, a number of basic questions have not been answered. In expla ining the pathophysiology of silent ischaemia, factors affecting both the d emand end the supply side are now being recognized. With the exception of c ertain well-defined groups, it is not clear why some patients are mostly sy mptomatic, while other patients are predominantly asymptomatic There appear to be many factors influencing the ischaemic pain threshold, Studies inves tigating the prevalence of silent ischaemia show a remarkably high prevalen ce of silent ischaemia in different patient groups. Patients with hypertens ion but without coronary artery disease form a specific and vulnerable high -risk population that is particularly prone to silent ischaemia. Since chan ges at the macrovascular level are not responsible, various factors negativ ely influencing either cardiac supply or demand have been investigated. A r educed coronary reserve is central in explaining the increased prevalence o f silent ischaemia in hypertensives. Left ventricular hypertrophy renders m eaningful detection of ST segment changes difficult, but a possible solutio n dealing with this problem is offered by applying more stringent criteria in terms of minimal ST depression in the definition of ischaemia. The treat ment of silent ischaemia is largely the same as for angina pectoris, but wh ether therapy should be directed at elimination of all ischaemic episodes o r only of symptomatic episodes depends on further prospective work addressi ng this question. J Hypertens 18:1355-1364 (C) 2000 Lippincott Williams & W ilkins.