Laura Seitz, Deseret Morning News
Dr. John Day

You can live with some heart arrhythmias; others left unattended will kill you.

But all can be treated, according to Dr. John D. Day and Dr. J. Peter Weiss, who will address heart arrhythmia during tomorrow's Deseret Morning News/Intermountain Health Care Hotline. The two cardiologists with the Utah Health Clinic Arrhythmia Service at LDS Hospital will take phoned-in questions from 10 a.m. to noon.

The heart is an "electric" muscle, and an arrhythmia is an electrical problem that disrupts its ability to beat at a steady pace. Just as wiring in the house can go awry, so can the heart's circuitry. Whether arrhythmia is caused by a short circuit or an extra pathway, the result is typically either a heartbeat that's regular but too fast or slow, or an irregular, even chaotic heartbeat.

After medical history, blood pressure and overall health are assessed, other tests may be run, including electrocardiogram (ECG/EKG), an echocardiogram, a "stress test" (an ECG while exercising), use of a monitoring device, tilt-table testing or an electrophysiology study.

Treatments vary, from use of medication to ablation, where the circuitry is altered by cauterizing it, or use of an implantable device like a pacemaker or defibrillator.

"You can live with atrial arrhythmia," said Day. "Most people feel the arrhythmia, but particularly in the older age group, they just feel tired and don't know why."

Supraventricular tachycardia (SVT), which people are born with although they don't become arrhythmic until younger adult life or later, is caused by an extra electrical pathway and features a very fast and regular heartbeat — in most cases, between 130 and 220 beats per minute. It causes shortness of breath, chest discomfort and other symptoms, such as dizziness or light-headedness.

SVT is episodic, with the heart rate going from 60 to 220, for instance, suddenly, but it tends to happen more often and last longer as people get older. An episode may send someone to the emergency room for medication to stop it.

It's easily curable using cardiac catheter ablation. The cardiologist goes in through the vein in the leg, identifies the extra electrical pathway and shuts it off permanently by cauterizing it. In about 97 percent of cases, that's the end of it, Day said.

Other atrial arrhythmias develop over time. The most common, atrial fibrillation, can cause strokes.

A recent study said one in four people over their lifetime will develop atrial fibrillation, which results in total electrical chaos of the two upper chambers of the heart. Its causes are high blood pressure, heart failure and age.

Atrial fibrillation ended Larry Bird's career playing basketball, and its complications killed Richard Nixon. Bill Bradley experienced recurrent episodes while running against Al Gore for the Democratic nomination in 2000.

About 25 percent of all strokes are believed caused by atrial fibrillation. Amid the electrical chaos, the heart's upper chambers don't pump blood, and if a resulting clot travels to the brain, it's a stroke.

It can also lead to cardiomyopathy or heart failure. And unlike SVT, it may never stop unless it's treated.

The first step is to try to prevent strokes, usually with a strong blood thinner like warfarin. Lower-risk patients may be treated with aspirin. Then the rhythm is treated.

Doctors may do cardioconversion, shocking the patient to reset the heart's rhythm or give medications to control the rhythm. There are anti-arrhythmic drugs designed to hold rhythm, Day said, although all of them have potentially dangerous side effects. Recently, ablations have been used for the condition, but they are very complex.

In July, the LDS Hospital doctors will present data showing that in 92 percent of their patients the ablation eliminated the condition. Of those, 72 percent were able to get off all the drugs that were being used to treat atrial defibrillation. But because it's more risky, ablation is only used when the anti-arrhythmic drugs are not effective.

Atrial flutter is a second cousin to atrial fibrillation, and some patients have both. Flutter starts with an abnormal circuit that develops in the heart over the years, related to hypertension, heart failure, age and sometimes lung disease. Patients with emphysema, for instance, may be predisposed to it. It's treated with anti-arrhythmic medications and cardioconversion to stop episodes, or ablated to cure it. Unlike atrial fibrillation, ablation is low-risk, making that a first-line treatment option.

The other condition, atrial tachycardia, with a very fast heartbeat, is very rare, he said.

Saturday: Ventricular arrythmias and implantable devices