Irregular Heartbeat Fairly Common Past Age 60 : Diagnosis: Atrial fibrillation can interfere with ability to pump blood. It is usually effectively medicated but can be life-threatening.
Atrial fibrillation, the condition with which President Bush was diagnosed Saturday, is a form of irregular, rapid heartbeat that can interfere with the heart’s ability to pump blood.
The condition is relatively common in older individuals, occuring in about 4% of people over age 60. Usually, it can be effectively treated with medications and has no effect on life span. But sometimes it is life-threatening.
Physicians said that the key factors in assessing the seriousness of the condition are the underlying health of the patient and the rapidity of the heartbeat.
The faster the heartbeat, the greater the likelihood that the condition may cause immediate symptoms, such as shortness of breath, palpitations, chest discomfort, dizziness and weakness. But sometimes people are not aware that they have the problem until a physician discovers it during a routine physical.
In the long term, patients with atrial fibrillation who are otherwise healthy usually can resume normal lifestyles quickly and may suffer no lingering consequences. Bush would appear at this point to fall into the category of patients with a favorable prognosis.
“It is relatively common that atrial fibrillation occurs without any identifiable heart problem and hopefully that is what they will find with Bush,” said Dr. William G. Stevenson, a cardiologist at UCLA Medical Center.
Presidential Press Secretary Marlin Fitzwater said in Washington that “the medical diagnosis and treatment to this point are indicating a routine handling of this. We don’t have any undue alarm.”
Fitzwater specifically said there is no evidence that the President suffered a heart attack, or an interruption of the blood supply to part of the heart muscle. A heart attack is usually far more serious than atrial fibrillation.
Some atrial fibrillation patients with high blood pressure or underlying heart disease, such as diseased heart valves or heart arteries, have more problems. For instance, they may have recurrent episodes of rapid heartbeat and could require treatment with electrical shocks delivered to the heart. They also may suffer strokes, if small blood clots form in the chambers of the heart and travel through the circulatory system to the brain.
Many factors favor the President, who is 66.
After undergoing a full medical evaluation in March, his physicians pronounced him healthy. At Bethesda Naval Medical Center on Saturday, Bush received an electrocardiogram, which showed no abnormalities except the irregular heart rhythm, according to Fitzwater. The President also had an ultrasound examination of the heart, which showed “no structural abnormalities” and “normal heart function,” Fitzwater said.
Bush is being treated with digoxin, a drug that can slow the heart rate. Apparently, he has responded well to the medication, although Fitzwater did not say whether he has reverted to his normal heartbeat. Digoxin treatment is likely to continue for several weeks and then be re-evaluated.
Typically, in treating a first episode of atrial fibrillation, “the sequence of events is to administer digoxin and that slows the heart rate,” Stevenson said. “Most of the time the patient reverts spontaneously to a normal heart rhythm within several hours.”
He added: “It sounded like (the President’s doctors) felt he was very stable. There was no indication (from Fitzwater’s statement) that there was anything surprising.”
Bush was jogging when he first experienced symptoms but it is uncertain whether exercise triggered his abnormal heart rhythm. Physicians said exercise does not cause atrial fibrillation, although it may bring on the problem in people who are predisposed to the condition. Alternately, Bush may have developed the abnormal heartbeat earlier, but only became aware of it because he was exercising.
The human heart has four chambers, two upper holding chambers known as the atria and the two main pumping chambers known as the ventricles. Normally, the heart pumps about 75 times a minute.
With age, small areas of scarring develop in the atria. Cardiologists believe that these scars probably explain the development of atrial fibrillation in instances where no underlying illness is found.
The atria first contract to fill the ventricles, and then the ventricles pump blood to the rest of the body. When atrial fibrillation develops, the atria contract rapidly and with no coordination. As a result, the electrical system that conducts the heartbeat is unable to respond properly. The heart rate usually increases to 130 beats a minute or more but the actual rate can vary widely, sometimes topping 200.
President’s Heart Condition
Atrial fibrillation is a heart condition marked by rapid, unsystematic contractions of the upper heart chambers, or the atria. It causes the lower chambers, or the ventricles, to beat irregularly, usually at 130 to 150 beats per minute. The fast heart beat reduces the heart’s efficiency. Symptoms can include shortness of breath, lightheadedness or chest discomfort. Serious causes of atrial fibrillation include a heart attack or diseased heart arteries. Often, no underlying cause is found.
