Thousands of Americans every year develop an abnormal heart rhythm after having major surgery. These episodes have long been considered a fleeting phenomenon that is generally not a cause for concern.
But a large new study suggests that doctors should take these abnormal heart rhythms, known as atrial fibrillation, or A-fib, more seriously. It found that patients who experienced one or more episodes after surgery had a striking increase in their risk of having a future stroke. The findings are likely to encourage doctors to potentially monitor and in some cases treat the patients who experience them.
“This is telling us that once you see atrial fibrillation in the hospital, that’s a marker of potential trouble to come,” said Dr. Donald Easton, a clinical professor of neurology at the University of California, San Francisco medical school. “You may have identified a patient who is going to develop atrial fibrillation in the future, and here’s your chance to intervene and treat it and prevent strokes.”
Dr. Easton, who was not involved in the new research, said that if he had a patient now who developed an episode of atrial fibrillation after surgery, “I would be monitoring that patient like crazy for weeks.”
Outside of surgery, a diagnosis of atrial fibrillation is recognized as a major risk factor. It is the cause nationwide of at least one out of six ischemic strokes, the most common type of stroke, which disrupt blood flow to the brain. Strokes that are linked to atrial fibrillation are often more debilitating and lethal than strokes attributed to other causes.
But episodes of atrial fibrillation that occur around the time of a surgical procedure have long been thought of differently. They are generally viewed as isolated and temporary events brought on by the stress of going under the knife.
About 200 million operations of any kind are performed worldwide every year, and at least two million of these patients experience atrial fibrillation, which occurs when the heart’s upper chambers, the atria, beat chaotically. The rate is particularly high after cardiac surgery; as many as a third of these patients will have an episode.
“Historically, we’ve taught that these events are fairly common during surgery and that they don’t mean anything in the vast majority of patients,” said Dr. Clay Johnston, a stroke neurologist and the dean of the Dell Medical School at the University of Texas at Austin. “You make sure there’s no acute heart injury, but beyond that, there’s no reason to be concerned.”
The new study, to be published in JAMA on Wednesday, showed otherwise.
The researchers followed more than 1.7 million people who had inpatient surgery in California hospitals during a three-year period, looking only at patients who had not had a diagnosis of atrial fibrillation before their surgery.
About 25,000 of these people went on to have an episode after their operations. Compared with the other patients, their likelihood of subsequently having an ischemic stroke was much greater. Atrial fibrillation after cardiovascular surgery increased the risk of a future stroke by 30 percent. For all other operations, it doubled the risk.
The researchers called for more studies to evaluate the relationship between heart rhythm abnormalities after surgery and strokes and to determine the best strategies for these patients. But what is clear now is that an episode that occurs after surgery needs to be looked at as a warning sign, said Dr. Hooman Kamel, a neurologist at the Brain and Mind Research Institute at Weill Cornell Medical College in New York, and an author of the study.
“It needs to be taken very seriously,” he said. “It needs to be documented on the patient’s chart. It needs to be communicated to the patients and their outpatient physicians. And there needs to be a plan for the close monitoring of these patients.”
Researchers have found in recent years that many people with sporadic atrial fibrillation go unrecognized. Some people with the condition notice heart palpitations, shortness of breath and dizziness. But many have no symptoms at all.
Dr. Kamel said that major surgery and the physiological stress it induced apparently helped bring some of these patients with underlying arrhythmia to light.
That may have been the case with Neil Dufoe, 72, a retired factory worker from Cedar Rapids, Iowa. Mr. Dufoe had triple-bypass surgery in June. A few days later, during his hospital stay, he was on the phone with his wife when he felt his heart begin to race. A moment later, he fainted.
“It was a blur,” he said. “The phone hit the floor, and the next thing I remember is the nurses talking to me. They said I was out for 10 seconds.”
Mr. Dufoe was kept in the hospital longer and sent home with a heart monitor that detected additional arrhythmias. His doctor, Dr. Prashant D. Bhave, one of the authors of the new study, also put Mr. Dufoe on an anticoagulant medication, which is used with atrial fibrillation patients to prevent clotting that can lead to strokes.
Mr. Dufoe said he was being followed closely and was relieved that his atrial fibrillation came to light.
“I’m doing very well now and I feel fine,” he said. “I go to cardiac rehab three days a week. I’m on treadmills, bicycles, all that kind of stuff.”