TY - JOUR T1 - Renin-angiotensin system mediated mechanisms: cardioreparation and cardioprotection JF - Heart JO - Heart SP - i18 LP - i19 DO - 10.1136/heart.84.suppl_1.i18 VL - 84 IS - suppl 1 AU - Christian G Brilla Y1 - 2000/09/01 UR - http://heart.bmj.com/content/84/suppl_1/i18.abstract N2 - The Framingham heart study has convincingly shown that, in the presence of left ventricular hypertrophy (LVH) of any cause, there is an increased risk for all major cardiovascular events, including the development of cardiac failure. The risk of cardiac failure for men and women alike rises six to 18 times in the presence of LVH.1 A number of changes occur within the myocardial structure during the development of LVH. There is a tremendous increase in myocyte size in patients with dilated cardiomyopathy, hypertensive heart disease, coronary artery disease or post-myocardial infarction. The major physiological stimulus for myocytes to undergo hypertrophy is mechanical stress, or stretch, either provided by increased preload, or increased afterload, or a combined increase in both. In a study looking at cultured cardiac myocytes under serum free conditions—that is, no hormones or growth factors were present—it was found that stretching caused myocytes to hypertrophy.2There was upregulation of the protooncogenes c-fos and c-jun, and even more importantly, an overexpression of the contractile proteins myosin and actin. In addition to increased load, other triggers for myocyte hypertrophy include angiotensin II, catecholamines, thyroxin, and growth hormone. In patients with chronic failure caused by hypertensive heart disease, endomyocardial biopsies show diffuse interstitial and perivascular fibrosis in addition to myocyte hypertrophy. This is true for the pressure overloaded left ventricle and the non-overloaded right ventricle. COLLAGEN VOLUME FRACTION When adverse changes within the cardiac interstitium are quantified using quantitative video densitometry to measure collagen volume fraction, an eightfold increase is found in patients with hypertensive … ER -