Though it is national news that John Edwards has an irregular heartbeat, cardiologists say the former U.S. presidential candidate's condition is one common with millions of other Americans.

More than 5 million people in the United States suffer from abnormal heart rhythms, or arrhythmias, that can lead to serious problems such as stroke or in extreme cases sudden death.

The rhythmic beating of the heart results from the transmission of electrical impulses through the organ.

When those are mistimed and uncoordinated, the heart fails to function properly, resulting in complications that can range from fatigue, lightheadedness, fainting, palpitations, shortness of breath and chest pain to drastic collapse and sudden cardiac arrest.

Edwards has suffered from at least three incidents since being diagnosed with the condition in December, said the judge overseeing Edwards' upcoming federal trial. And a family friend told NBC this week that Edwards had lost consciousness on at least one occasion.

Letters from two cardiologists, mentioned in federal court last week, said that if Edwards' "serious condition" is left untreated, it could give him grave problems.

Catherine Eagles, the judge presiding over the legal proceedings, agreed last week to grant a third delay of the trial, citing the health issues of the 58-year-old former U.S. senator who now lives outside Chapel Hill.

The judge said notes from Edwards' doctors, which are sealed from public view, mentioned a treatment course that would have made Edwards unavailable for court for several days in mid-February.

The judge said the doctors had advised Edwards to avoid long hearings before the procedure. He also has been advised against driving long distances.

Triangle cardiologists, without knowing the specifics of Edwards' condition, offered generalizations this week for the many ways to treat a patient with an irregular heartbeat.

About 2.8 million Americans have atrial fibrillation, the most common type of irregular heartbeat.

The condition occurs when the top chambers of the heart, or the atria, are not in synchronization with the pumping actions of the bottom chambers.

Such irregularities are not immediately life-threatening, and the heart sometimes gets back into rhythm on its own.

Stroke risk

But if that arrhythmia continues, it can eventually cause a life-threatening complication, the formation of blood clots that can move to the brain and cause a stroke.

Dr. Tristram D. Bahnson, director of the Duke Center for Atrial Fibrillation, and Dr. Mohit Pasi, a cardiologist at Rex Health Care, said there are many ways to treat an irregular heartbeat.

They range from electrical shock to blood thinners that prevent clotting and stroke to a procedure called catheter ablation.

That involves inserting a thin tube into a blood vessel, usually through the groin, then threading it though the body until it reaches the heart.

When it reaches the area causing abnormal rhythms, a device emits radiofrequency energy to destroy the tissue disrupting the electrical impulses.

Pasi said there are times when a patient is admitted for two to three days as doctors try drug therapies and monitor their success or failure.

"We don't jump into ablation right away," Pasi said. "Most of the time you try drug therapy first."

Criminal trial looms

Edwards is facing a criminal trial this spring on accusations that he flouted campaign finance laws to hide his extramarital affair with Rielle Hunter, a former campaign videographer, and her pregnancy from that relationship.

Prosecutors contend he secretly obtained nearly $1 million from two wealthy supporters that should have been classified as campaign contributions.

The payments were used to cover living, medical and travel expenses for Hunter.

Edwards has said he did not break the law.

His attorneys argue the payments were gifts from friends meant to keep Edwards' affair and news of the child from his wife.

Edwards' attorneys are to give Eagles, the judge, a medical update about their client at the end of February.

Jury selection is tentatively set to begin March 26.