Physiologic or pathologic hypertrophy

Physiologic hypertrophy occurs as the result of exercise conditioning and is characterized by normal or supranormal left ventricular (LV) contractile function and reversibility of structural alterations. Whether hypertrophy produced by chronic abnormal loading can be termed ‘physiologic' is a matter of debate because in experimental pressure overload hypertrophy normal in vivo ventricular function may be associated with abnormal in vitro function of the papillary muscles. In patients with moderate LV hypertrophy from aortic valve disease (angiographic mass < 180 g/m2) ejection fraction (EF) is preserved, but at similar levels of afterload, when mass exceeds 180 g/m2, EF is depressed. Comparison of LV function with myocardial structure (endomyocardial biopsies) has shown that in patients with compensated LV function and those with left heart failure (EF 20 mm Hg and/or cardiac index 2·5 l/mm/m2)interstitial fibrosis (IF) was increased to a similar extent (16 and 18%: normal