Heart rhythm is controlled by factors both intrinsic and extrinsic to the heart itself. The most common damage to the heart's "wiring" comes from damage caused by decreased blood flow from clogged coronary arteries, or from muscle death caused by a heart attack. Additionally, certain drugs and toxins can affect heart rhythm as well.
The development of potentially life-threatening dysrhythmias during the immediate period following an MI (myocardial infarction) is the reason that heart attack patients are monitored very closely in a CCU (coronary care unit). One therapy which can increase the risk of dysrhythmia is thrombolytic treatment of the clogged coronary artery. When this is successful, there is a sudden influx of blood into the blood-starved area. This often results in dysrhythmia, which can be fatal. The culprit is in part a free radical reaction. Therefore, any therapy directed at this free radical burden could be potentially helpful.
In fact, recent studies have shown that such treatment is important in this setting. A 1998 study looked at patients with a recent AMI (acute myocardial infarction). For 28 days one group received oral treatment with coenzyme Q10 (coQ10, 120 mg a day), and the other group received a placebo. After treatment, total arrhythmias were 9.5% in the coQ10 group, compared to 25.3% in the placebo group. When measuring angina pectoris, only 9.5% of coQ10-supplemented patients were symptomatic compared to 28.1% on placebo, while poor left ventricular function was observed in 8.2% of those patients taking coQ10 compared to 22.5% on placebo.
Total cardiac events, including cardiac deaths and nonfatal infarction, were also significantly reduced in the coQ10 group compared with the placebo group (15.0% vs. 30.9%). Other recent studies have demonstrated that giving patients who have recently suffered an AMI omega-3 fatty acids protects them from the development of dysrhythmias in the immediate post-AMI period. Omega-3 fatty acids may be found in flaxseed, perilla, and fish oils.