New aspects of myocardial oxygen consumption. Invited review

This paper gives an overview of mainly new aspects of myocardial oxygen consumption. Experimental models have quantified energy consumption in mechanical work, excitation-contraction coupling and metabolic processes. However, there are still contradictory observations between hemodynamic, thermodynamic and subcellular models and further knowledge of subcellular energy consumption is anticipated. The energy cost of contractility-enhancing drugs has been investigated in various experimental and clinical studies, and the calcium sensitizers have been proven to be the most mechanoenergetically efficient. An "oxygen-wasting" effect in post-ischemic hearts was observed some 15 years ago. The mechanism for this inefficiency has been thoroughly investigated, and seems to be caused by an inefficient excitation-contraction coupling and/or inefficiency in the contractile apparatus. The mechanoenergetic efficiency in heart failure needs further investigation.