Heart muscle cells contract and relax in a rhythmic way. This action pumps blood around our bodies effectively.
Contraction and relaxation of heart cells is partly managed by a controlled flow of calcium particles called ions. Faults in calcium ion flow can cause life-threatening irregularities in our heart’s rhythm. These irregularities are called arrhythmia.
Most of the calcium that activates heart cell contraction comes from a store within the cell, called the sarcoplasmic reticulum (SR). Calcium moves in and out of this store in a tightly regulated way, through specialised channels and gates, and in response to a variety of signals in the cell.
Sometimes signals get confused, or sometimes the specialized channels are faulty. This can cause the release of too much calcium from the cell’s store. In turn this disrupts the electrical current in the heart and the heart beats abnormally.
In the most serious cases this abnormal beat can cause sudden death.
BHF Professor David Eisner and his team are investigating in detail how calcium regulation works and what happens when it goes wrong.
Heart attack and arrhythmias
In heart attack, the heart muscle is deprived of blood. Restoring blood flow is an essential treatment to save heart muscle but it can also cause other problems. The technical name for restoring blood flow is reperfusion.
Spontaneous calcium release in the heart cells can occur when doctors restore blood flow, leading to irregular heartbeats. Professor Eisner’s team are investigating the changes in heart cells caused by reperfusion to understand how we can avoid them. The damage sustained by the heart during, and after, a heart attack can lead to heart failure.
If the workload of the heart increases it becomes enlarged. This can increase the incidence of arrhythmias and, if excessive, can lead to heart failure. Professor Eisner's Manchester team is investigating how altered calcium signalling plays a part in this damaging process.
Heart failure is a debilitating condition that can have dramatic effects on the whole family as they struggle to cope with the care of a loved one. Read more about Charlotte and James' Story as they come to terms with their mother's heart failure.