Fibrosis and impaired Ca 2+ signalling in heart failure.

Fibrosis and impaired Ca 2+ signalling are two prominent features of the failing heart that are generally considered as separate entities. Our discovery of increased amounts of collagen (types I, III, and VI) within the lumen of the transverse (T)-tubules in the failing heart suggests they may be directly linked. T-tubules are plasma membrane invaginations that facilitate a rapid transmission of the action potential deep within the myocyte where they facilitate a synchronous Ca 2+ release that triggers contraction. T-tubule remodelling causing impaired Ca 2+ release and contraction in heart failure with reduced ejection fraction is well established. However, what drives this mechanism is less clear. In this commentary, I will briefly outline the evidence that supports the role of excessive collagen disposition driving t-tubule remodelling in the failing heart.