Women with breast cancer are known to have heart problems related to treatment, and now a new study shows their odds of developing an abnormal heart rhythm known as atrial fibrillation (A-fib) may increase in the wake of a breast cancer diagnosis.
Women who develop A-fib within a month of a breast cancer diagnosis are more likely to die from heart- or blood vessel-related problems within a year, the new research suggests.
A-fib occurs when the upper chambers of the heart quiver chaotically, causing a fast and irregular heartbeat. Symptoms may include heart palpitations, breathlessness, dizziness, and/or extreme fatigue. When left undiagnosed or untreated, A-fib dramatically raises the risk for stroke and heart failure.
Exactly why these two conditions travel together is not fully understood yet.
"Traditional risk factors such as age, cardiovascular risk factors remain risk factors for A-fib after a breast cancer diagnosis," said study author Dr. Avirup Guha, an assistant professor of medicine at Case Western Reserve University in Cleveland. But "surgery, chemotherapy, inflammation and imbalances in the body's normal processes caused by the cancer may be implicated," he said.
Stress can also contribute to A-fib, and the emotional stress that often accompanies a new breast cancer diagnosis may play a role, but the researchers didn't look at stress in this study.
For the study, the researchers analyzed data on more than 85,000 women aged 66 or older who were diagnosed with breast cancer between 2007 and 2014. These women, along with their cancer-free counterparts, were followed for one year to see who developed A-fib.
The incidence of women with breast cancer who developed new-onset A-fib was 3.9%, and this risk peaked in the two months following their diagnosis. By contrast, just 1.8% of women without breast cancer developed A-fib during one year of follow-up.
Women with more advanced breast cancer had a higher risk for developing A-fib, regardless of their treatment plan, the study showed.
A-fib was also more common in women who underwent complex surgeries such as a mastectomy.
There was no increased risk of dying within one year of breast cancer diagnosis for women in the study who had A-fib first, possibly because they were already seeing a cardiologist, Guha noted.
More research is needed to determine if prescribing heart medication to all new breast cancer patients can reduce the risk of A-fib and death, and/or if all people with newly diagnosed breast cancer should be monitored to rule out this dangerous heart rhythm.
The study did have its limitations. The findings may not apply to younger women. In addition, follow-up was only one year, and chronic heart problems caused by radiation treatment tend to show up much further down the road.
The findings were published Nov. 14 in the European Heart Journal.
Outside experts point out that people with breast cancer are known to be at a higher risk for heart-related problems.
"Breast cancer and cardiovascular disease are known to share several common risk factors, and the current work further extends our current knowledge base by highlighting the increased incidence of atrial fibrillation among breast cancer patients," said Dr. Anthony Yu, a cardiologist at Memorial Sloan Kettering Cancer Center in New York City.
"Optimization of cardiovascular risk factors and management of preexisting or newly diagnosed cardiovascular conditions should be prioritized for breast cancer patients and may help to improve overall clinical outcomes," Yu said.
Breast cancer patients undergoing treatment are already screened for decline in heart function since it is a well-known side effect, added Dr. Aeshita Dwivedi, a cardiologist at Lenox Hill Hospital in New York City.
"Patients with breast cancer tend to develop risk factors that may cause atrial fibrillation, for example, high blood pressure or heart failure," she said. "Moreover, treatment of breast cancer including surgery, chemotherapy and radiation, all increase the risk of developing conditions that give rise to atrial fibrillation."
Breast cancer as well as its treatments can lead to inflammation and silent damage of the heart muscle, which may also increase risk for heart disease and A-fib, Dwivedi said.
These findings are "hypothesis-generating and may alert clinicians to maintain heightened awareness of the link between these two conditions and be more proactive about evaluating these patients, especially if they are symptomatic," she said.
Still, it's too early to make any sweeping recommendations about how and when to screen these women. "Further studies are needed to better understand the mechanism of this association and evaluate the need for regularly screening breast cancer patients for atrial fibrillation," Dwivedi said.