FrankStarlingrelatie

The FrankStarlingrelatie, also known as the Frank-Starling law, describes how the heart automatically adjusts its stroke volume in response to changes in venous return. Within physiological limits, an increased end-diastolic volume leads to a greater stroke volume and thus higher cardiac output. This mechanism helps the heart match its pumping capacity to the amount of blood returning to it.

The underlying idea is the length–tension relationship of cardiac muscle. When the ventricles fill more during diastole, the myocardial fibers are stretched to a more optimal length, enabling a stronger contraction. As preload rises, contractile force increases due to more effective cross-bridge interactions and improved alignment of contractile elements. The relationship levels off if fibers become overly stretched and the benefit declines.

Clinical and physiological significance lies in its role in regulating cardiac output to meet bodily needs. During activity or reduced blood loss, venous return increases and the heart responds by increasing stroke volume. The Frank-Starling mechanism is influenced by factors such as preload, afterload, contractility, and diastolic function. In heart disease, especially dilated cardiomyopathy or heart failure, the ability to augment stroke volume with increased preload can be impaired, and the relation may shift or flatten.

Historically, the relationship is attributed to Otto Frank and Ernest Starling, who described it in the early 20th century. It remains a foundational concept in cardiovascular physiology, illustrating how intrinsic properties of cardiac muscle help regulate cardiac output.