David Fedida finds additional heart danger of high cholesterol

New research suggests that high cholesterol might change the normal heartbeat, which could lead to sudden death.

For many years, we’ve heard that high cholesterol can clog arteries and increase heart attack risk. But new research suggests that high cholesterol might pose an additional danger – it can also change the normal heartbeat, which could lead to sudden death.

David Fedida: It’s an arrhythmia that’s the terminating effect – an abnormal electrical beat.

EarthSky spoke with Dr. David Fedida of the University of British Columbia. He explained that the heartbeat is generated by a small electrical current, which flows through the heart. This electricity, in turn, relies on the cells of the heart.

David Fedida: Normally, the cells are like little batteries. They sit with a negative voltage across them. And then when the impulse comes along and the heart beats, these little channels, these little proteins, open these pores, and the voltage changes.

Fedida said these protein pores are key to conducting the heart’s electrical current. In a 2009 study, Fedida found that high cholesterol affects the distribution of the protein channels across the cells.

David Fedida: If these proteins aren’t in the right place, and opening and closing at the right time, then the heartbeat isn’t normal.

He said the way cholesterol changes these proteins can cause the heartbeat to quicken, or even fail. However, he said, the cholesterol-lowering drugs that many people with high cholesterol already take may help normalize the heart’s electrical activity. An abnormal heartbeat is known as a cardiac arrhythmia. Dr. Fedida explained how arrhythmias occur.

David Fedida: For the heart to beat in an orderly way, which it does in all of us, normally, there’s an impulse that starts in the top left hand corner of the heart. It goes throughout all the cells of the heart, so all the cells fire together. You could imagine, for that to happen normally, everything has to be closely aligned and fit together. But, if something is going wrong, that can become abnormal. So this abnormality that occurs gives rise to an arrhythmia.

He said one of the things that can go wrong is within the cells themselves.

David Fedida: One of the amazing things I never really understood was that the proteins in our cells that cause muscles to contract don’t last very long – only a few hours or days. The body breaks them down and remakes again. These protein pores, that we call ion channels, in the heart’s electrical system are subject to the same control. They are synthesized inside the cell and they’re transported to the cell’s surface. They stay at the cell surface for a few hours, and then they internalize back into the cells and they are either degraded and remade again, or transported and reappear at the cell surface. That’s going on all the time in the normal heart.

Fedida said his study shows high cholesterol is a catalyst for disrupting the electrical flow of the heart.

David Fedida: We found that cholesterol affects that. It changes the way these little protein pores are normally trafficked, or recycled. That means, that’s going to alter number of channels and fundamentally alter the electrical activity in the heart. Since the heart’s electrical activity depends upon each element of the system working in concert, it could distort that electrical activity.

Fedida’s research was funded by the Heart and Stroke Foundation of BC & Yukon and was a collaborative study with Dr. Stephane Hatem at the University of Paris.

Lindsay Patterson