Left ventricular hypertrophy: an initial response to myocardial injury

The prevailing wisdom generally has been that the failing heart hypertrophies in response to increased wall stress. The increase in myocardial mass observed in heart failure is therefore a relatively late compensatory event geared to normalize wall stress. Although this is undoubtedly true, especially for heart failure resulting from a large anterior myocardial infarction accompanied by rapid left ventricular expansion, it is possible that an important form of hypertrophy occurs much earlier as an initial response to myocardial injury. One can hypothesize that the initial response to injury is a nonspecific phenotypic alteration of the cardiac myocyte to one of growth and development. Such changes may be driven by both trophic and mechanical forces and may be important in altering the architecture of the myocardial cell and surrounding cardiac interstitium. Preliminary data from a variety of models support the concept that neuroendocrine activity is an important component in the ventricular remodeling process, and that pharmacologic interventions designed to block systemic and tissue neuroendocrine activity may prevent excessive cardiac enlargement and its ultimate consequences. Because this concept has important implications for preventive cardiology, the results of several prevention trials, including the Cooperative North Scandinavian Enalapril Survival Study (CONSENSUS), Studies of Left Ventricular Dysfunction (SOLVD), and Survival and Ventricular Enlargement (SAVE) are awaited eagerly.