Heart Failure Linked to a Decline in Thinking and Memory, Study Finds

Cognitive decline is a common side effect of heart failure, new research published in Circulation: Heart Failure found.

Specifically, researchers discovered a link between a heart failure diagnosis and having problems with a broad range of mental processes, such as memory, paying attention, and planning.

“Knowing this will help caregivers and patients prepare better and get involved earlier if the patient is struggling,” said Supriya Shore, MBBS, a clinical assistant professor of cardiology at the University of Michigan, who led the study.

Here’s a closer look at the study’s findings—and why the heart and the brain are so closely connected.

Heart failure happens when the heart cannot pump enough blood and oxygen to other organs. Nearly 7 million people in the United States live with it.

High blood pressure and coronary artery disease, a condition in which cholesterol buildup narrows the arteries and reduces blood flow to the heart, are common causes of heart failure. 

Although its name might suggest otherwise, having heart failure doesn’t mean your heart suddenly stops beating. Instead, you might experience symptoms like shortness of breath, weight gain, and fatigue that develop gradually.

Shore got the idea to investigate the connection between brain health and thinking issues while interviewing caregivers of people with heart failure for a separate research project. “They universally were saying they noticed their loved ones were having cognitive decline,” she told Health, and that no one had discussed that side effect with them.

When Shore reviewed the research, she found little on the connection between cognitive decline and heart failure.

To better understand the link, Shore and her colleagues used data from six U.S. studies that included nearly 30,000 people whose cognitive abilities researchers followed between 1971 and 2019. None of the participants had a diagnosis of heart failure, stroke, or dementia when they started the studies. A little more than half were women, and 70% were white.

After following up with participants, researchers discovered that 1,407 received a heart failure diagnosis. Having heart failure was associated with a drop in several areas of cognition around the time of diagnosis:

• Global cognition, which includes a broad range of mental processes, like thinking, attention, language, and learning
• Executive function, or the ability to engage in higher-level cognitive skills, such as planning, problem-solving, and adapting to new situations
• Memory

Having fuzzy thinking around this time makes sense, considering people are typically diagnosed with heart failure after a big event, such as hospitalization, or when other symptoms become noticeable, said Hannah Rosenblum, MD, an assistant professor of medicine and cardiologist at Columbia University Irving Medical Center and Vagelos College of Physicians and Surgeons.

“Your whole immune system is ramped up; there are all these cytokines that are leaked into your bloodstream, and that can affect your cognitive function,” Rosenblum told Health. “The blood-brain barrier may also be breaking down as a result, and that can impact your cognitive function.”

Interestingly, the memory decline didn’t remain significant the longer people with heart failure lived with it. That wasn’t the case with global cognition and executive function, which decreased steadily as time passed.

It’s becoming clear that heart disease in general, including stroke, coronary artery disease, and heart failure, all affect cognition. While physicians don’t have a definitive answer as to why heart failure typically causes cognitive decline, the following factors may play a role:

• Changes to the heart. Heart failure weakens the heart muscle, reducing its ability to pump enough blood and oxygen to the brain, Johanna Contreras, MD, director of heart failure at Mount Sinai Hospital in New York, told Health. 
• Conditions that occur alongside heart issues. Cognitive decline may be amplified by other conditions associated with heart failure that also affect cognition, Contreras added. As many as 40% of people with heart failure also have diabetes, research shows, and growing evidence suggests diabetes alone can cause cognitive decline. Persistent high blood pressure, which is a common cause of heart failure, can also cause many tiny ischemias, or points where there is reduced blood flow, in the brain, Contreras said. These underlying conditions also lead to widespread inflammation in the body, according to Rosenblum.
• Slowing down. As heart failure—a pro-inflammatory disease in and of itself—progresses, new impairments further affect cognitive function. “During the end stages of heart failure, you become more frail. When you do less, the body gets used to doing less, and it sets up a vicious cycle, and that also affects cognition,” Shore said. 

Experiencing issues with planning and thinking can be especially problematic for people with heart failure, given the complex self-care required to manage the condition.

“Everything about managing heart failure is so patient-centered. You have to monitor your weight every day; you have to take at least five medications, sometimes multiple times a day,” Shore said. “This requires so much care coordination that requires cognitive function.”

She hopes that the study findings not only help patients prepare and take action sooner, but empower caregivers to do the same.

“Heart failure affects two people,” Shore said. “It’s not just the patient, but the caregiver that will also have an increased burden as the disease progresses.”