Submitted by Dr T on September 25, 2010 – 9:28am
Lightheadedness whatever the cause, is the result of insufficient blood flow to your brain. During some arrhythmias, the heart becomes less efficient and pumps less blood around your body. Since your brain is more sensitive to changes in blood supply than all your other organs, it will let you know with symptoms that may range from lightheadedness, to losing your conscience.
Hope this helps,