Properties of myocardium in cardiomegaly.

• The ventricular myocardium responds to a chronic increased work load by an increase in the myocardial mass. The functional significance of this adaptation has been an area of interest particularly because of the common clinical finding of an increased cardiac mass in cardiac failure. Since an increased myocardial mass is predominantly the result of the enlargement rather than the multiplication of the myocardial cells,some have suggested that this response may be detrimental since it must increase diffusion distances for metabolites/' However, functional studies, such as those of Beznak, Dieckhoff/' and Hasenfeld and Romberg have shown an increased cardiac work capacity with an increase in myocardial mass. Few studies have examined the basic properties of the enlarged myocardium. A preliminary report by the authors," later supported by the findings of Kerr, Winterberger, and Giambattista, suggested that the enlarged myocardium might even be capable of producing greater than normal tension per unit weight of nruscie.