Why and how is cell-to-cell conduction speed impaired by heart attack?

Adrenergic modulation of ventricular transmural conduction velocity is a novel factor governing electrical excitability in health and disease

Researchers in Glasgow are studying why, after heart attack, electrical conduction through the heart changes. When the heart beats, all of its cells must contract in coordinated fashion. To make this happen, an electrical signal spreads rapidly through the heart wall from cell to cell. When a person exercises, the speed of conduction of the electrical signal from cell to cell increases. How this happens is not clear, but the system can fail after a heart attack. This is important because electrical signals that are misaligned are more likely to cause dangerous irregular heart rhythms. Healthy hearts respond to signals from the sympathetic nervous system. That’s the network of nerves that regulates our bodies’ unconscious reflexes – the fight or flight response. When we exercise, sympathetic nerves signal for our heart to beat faster and the speed of electrical conduction to increase. Little is known about how and why the heart’s response changes after a heart attack and in heart failure. The researchers will compare the electrical signals of healthy hearts with those that have suffered heart attacks, with the aim of identifying the key factors that influence conduction through the heart. This is important, because it could help us develop new drugs or understand why some treatments only work for some people.