PATHOPHYSIOLOGY AND THERAPY: Left ventricular hypertrophy represents an important factor determining the prognosis of hypertensive patients. Hypertrophy as identified by electrocardiography (Table 1) or echocardiography (Table 2) characterizes patients with a significantly increased risk of mortality and arrhythmia. From the pathophysiological point of view this is based on hypertrophy of the media in resistance vessels, on interstitial fibrosis, on a reduced coronary flow reserve and on the occurrence of ischemia (Figure 1). The diastolic and (later) systolic function of the heart are disturbed (Figures 2 to 4). Antihypertensive therapy with beta blockers and diuretics leads to a reduction of left ventricular mass by 5-8%, with ACE-inhibitors and AT-blockers by 13% (Figure 5). Particularly ACE-inhibitors can effectively reverse of the above mentioned pathological processes. Regression of hypertrophy goes along with an improved prognosis and a reduction of atrial and ventricular arrhythmias (Figure 6). A symptomatic treatment of arrhythmias should always be accompanied by medical therapy aimed at regression of hypertrophy. Optimal therapy results in normalizes of blood pressure, leads to a regression of hypertrophy and induces cardiac reparation, which in turn improve left ventricular function, reduces microvascular ischemia stress and arrhythmias. These therapeutic desiderates are also pertinent for hypertensive heart disease in the prehypertrophic state, as in juvenile hypertension.