WEDNESDAY, Nov. 2, 2005 (HealthDay News) -- Add dyspnea, or difficulty breathing, to the growing list of risk factors that could signal heart trouble.
A study of nearly 18,000 people who had standard stress tests found that those with dyspnea but no other signs of heart problems were at more than twice the risk of death from cardiac causes (or any other reason) than those with angina, the chest pain that's typically regarded by doctors as a significant sign of risk.
The lesson for people when they visit a doctor is to be sure to mention any shortness of breath, said senior researcher Dr. Daniel S. Berman, director of cardiac imaging at Cedars-Sinai Medical Center in Los Angeles.
"The patient often doesn't think of it as a symptom," Berman noted. But when signs of a heart problem are discovered, "and we ask whether there is shortness of breath, they say 'yes,'" he noted.
The findings appear in the Nov. 3 issue of the New England Journal of Medicine.
Dyspnea has many causes, and physicians routinely ask people if they have trouble breathing, said Dr. Alan Rozanski, director of nuclear cardiology at St. Luke's-Roosevelt Hospital in New York City, and another member of the research team. He said trouble breathing is often a tip-off to the physician that a patient may have some underlying lung disease, maybe even heart failure.
But until now, only a few studies, most with a limited number of participants, have looked at whether dyspnea is a predictor of cardiac events, Rozanski said.
The New York team divided their 17,991 patients into five groups based on the number and type of symptoms: no symptoms, two different forms of angina, chest pain not caused by angina, and dyspnea alone.
After an average follow-up of nearly three years, the death rate among patients with dyspnea was significantly higher than for those with any other symptom or no symptoms -- even in patients with no known history of coronary artery disease.
The risk of sudden death was also four times higher for patients with dyspnea and coronary artery disease than for people with no symptoms, the researchers noted.
The bottom line: "People who have developed shortness of breath without any obvious lung problem should consider whether it is of cardiac origin," Berman said.
The fact that dyspnea is a greater indicator of cardiac risk than angina -- which has traditionally been regarded as the most ominous symptom of heart disease -- highlights the importance of letting doctors know about any shortness of breath, Berman said.
The findings could influence cardiologists' decisions in sending patients for cardiac stress tests, Rozanski said.
"For years, cardiologists have focused on chest pain as the primary symptom," he said. "They consider a variety of other factors as well, including depression, lack of sleep and fatigue. This study increases interest in looking at other factors."
"We should think of shortness of breath not only in terms of lung disease," Rozanski added. "We might need to screen a little more deeply for coronary artery disease. Someone with dyspnea might have a heightened need to undergo stress testing or other screening."
Rozanski said the study is already affecting decisions on stress testing in his practice. Now, when evaluating the need for an individual to have the test, he includes such factors as age, chest pain and gender (men are more likely to be referred for the test). "If someone has an intermediate risk, the presence of shortness of breath might tip me over," he said.
But Rozanski added there is "one important caveat."
"This study was done in a population of middle- to upper-class white individuals," he said. "We know that cardiac risk can vary by gender, ethnicity and other factors. To see whether dyspnea is as predictive in African-Americans or Hispanics, another population study has to be done."
An overview of dyspnea is provided by the National Library of Medicine.