Myocardial calcium regulation

Myocardial calcium regulation refers to the tightly controlled processes governing the movement and concentration of Ca²⁺ ions within cardiac myocytes. This system orchestrates each heartbeat through excitation–contraction coupling: depolarization opens voltage-gated L-type Ca²⁺ channels allowing extracellular influx; this triggers further release from the sarcoplasmic reticulum via ryanodine receptors (RyR2). The resulting rise in cytosolic Ca²⁺ binds troponin C on myofilaments to initiate contraction. Relaxation follows as SERCA pumps sequester cytosolic Ca²⁺ back into the SR while sodium/calcium exchangers extrude excess ions from the cell. Dysregulation contributes directly to heart failure progression, arrhythmias due to diastolic SR leak via dysfunctional RyR2 channels, and impaired contractility seen after ischemic injury. Multiple drug classes target individual proteins within this regulatory network rather than "myocardial calcium regulation" as a singular therapeutic entity[1][2][3][4].

Other names

Cardiac calcium handlingCardiac excitation–contraction couplingCalcium cycling in myocardium

Drugs act by modulating specific components involved in myocardial calcium handling. For example, L-type Ca²⁺ channel blockers reduce Ca²⁺ influx during action potentials. β-blockers decrease cAMP-mediated enhancement of LTCC and RyR2 activity. Agents that enhance SERCA function increase SR Ca²⁺ uptake for improved relaxation.