thus , since myocardial energetics is involved in acute volume overload , two possible means of adaptation may be considered : ( a ) tachycardia may alleviate the energetic cost of each beat , thus improving heart mechanical efficiency and ( b ) conversely , if hr remains stable , it may do so at the expense of the energetic cost of the myocardium for each beat , with efficiency not actually being enhanced .
C0018787
heart
C0027061
myocardium