The Control of Diastolic Calcium in the Heart: Basic Mechanisms and Functional Implications

Normal cardiac function requires that intracellular Ca2+ concentration ([Ca2+]i) be reduced to low levels in diastole so that the ventricle can relax and refill with blood. Heart failure is often associated with impaired cardiac relaxation. Little, however, is known about how diastolic [Ca2+]i is regulated. This article first discusses the reasons for this ignorance before reviewing the basic mechanisms that control diastolic [Ca2+]i. It then considers how the control of systolic and diastolic [Ca2+]i are intimately connected. Finally, it discusses the changes that occur in heart failure and how these may result in heart failure with preserved versus reduced ejection fraction.