Heart Failure: The Silent Villain Behind Brain Shrinkage

Heart failure can affect the brain, increasing the risk of memory problems and dementia. This study looked at more than 10,000 people and found that the worse the heart function, the smaller the volume of some brain regions, such as the hippocampus, which is essential for memory. This suggests that keeping the heart healthy may help protect the brain against aging and cognitive decline.

Heart failure is a condition in which the heart cannot pump blood efficiently to the body. This can affect several organs, including the brain. Previous research has shown that people with heart failure are at increased risk of memory problems, cognitive difficulties and even dementia.

Depending on the criteria used, between 25% and 70% of patients with heart failure have some degree of cognitive impairment, which can make treatment and quality of life more difficult.

Scientists still don’t fully understand why heart failure harms the brain, but some hypotheses include:

1. Reduced blood flow to the brain (hypoperfusion), leading to damage to nerve cells.

   
   

2. Inflammatory processes, which can affect the health of neurons.

   
   

3. Repetitive mini strokes (thromboembolic events), causing small, cumulative damage to the brain.

   
   

4. Production of substances by the heart, such as natriuretic peptides, which can affect the brain.

Animal studies have shown that a lack of blood supply to the brain can cause memory impairment, loss of neurons, and a decrease in the size of the hippocampus, a region crucial for learning and memory.

Some human studies have shown smaller brains and a higher risk of damage to the brain's small blood vessels, while others have found no such relationship.

Faced with this uncertainty, researchers decided to conduct a large study to understand how heart failure and other heart problems are linked to structural changes in the brain.

Researchers from Erasmus MC in the Netherlands analyzed data from 7 large international studies conducted in the United States and Europe. In total, 10,889 people with an average age of 66.8 years participated. The idea was to compare the results of heart and brain scans to see if there was a relationship between heart function and brain changes.

Steps of the study:

- Collecting heart data: Tests such as echocardiograms (heart ultrasounds) and cardiac magnetic resonance imaging were used to assess how well the heart was pumping blood. The scientists mainly analyzed:

• Ejection fraction (the percentage of blood that the heart pumps with each beat).

• Blood flow and relaxation of the heart (important to know if the heart fills and empties correctly).

• Presence or absence of heart failure.

- Brain data collection: Participants underwent brain MRIs to measure total brain volume (a smaller brain can be an early sign of neurodegeneration). They also measured the volume of the hippocampus (a region crucial for memory) and the amount of white matter lesions (spots in the brain that indicate damage to small blood vessels).

The researchers compared the heart and brain data using advanced statistical models, taking into account factors such as age, sex and other medical conditions. They used a meta-analysis to combine the results of all the studies and ensure that the findings were reliable.

The researchers found that the worse the heart function, the smaller some brain regions were. Specifically, people with moderate to severe heart dysfunction had smaller brains than those with healthy hearts.

Problems with heart relaxation (diastolic dysfunction) were associated with a smaller hippocampus, which can affect memory and increase the risk of dementia.

People with diagnosed heart failure had reduced brain volume, especially in the hippocampus. However, no clear link was found between heart dysfunction and damage to the white matter (an area of ​​the brain associated with communication between neurons).

The results suggest that heart problems can lead to changes in the brain even before cognitive symptoms appear. This means that maintaining a healthy heart may be essential to protecting the brain from aging and dementia.

The researchers recommend that future studies examine whether early treatment of heart failure can prevent cognitive decline. In addition, it would be interesting to follow participants over time to better understand how these brain changes develop.

This study reinforces the idea that the heart and brain are deeply connected and that taking care of cardiovascular health can have benefits for brain function.

READ MORE:

Clinical and Imaging Markers of Cardiac Function and Brain Health: A Meta-Analysis of Community-Based Studies

Amber Yaqub, Joshua C. Bis, Stefan Frenzel, Marisa Koini, Djass Mbangdadji, Gina M. Peloso, Rajesh Talluri, Alvaro Alonso, Martin Bahls, Robin Bülow, Marcus Dörr, Stephan Felix, Alison Fohner, Nele Friedrich, Edith Hofer, Maryam Kavousi, Lenore J. Launer, Tran Le, Will Longstreth, Thomas H. Mosley, Meike W. Vernooij, Henry Völzke, Katharina Wittfeld, Alexa S. Beiser, Hans J. Grabe, Vilmundur Gudnason, Mohammad Arfan Ikram, Bruce M. Psaty, Reinhold Schmidt, Jeannette Simino, Sudha Seshadri and Frank J. Wolters as Cross-Cohort Collaboration

Neurology. Volume 104 | Number 8. April 22, 2025

DOI: 10.1212/WNL.0000000000213421

Abstract: 

Cardiac dysfunction and heart failure are linked to cognitive impairment, but the underlying brain pathology remains undetermined. We investigated associations between cardiac function (measured by echocardiography or cardiac MRI), clinical heart failure, and structural markers on brain MRI, including volumes of gray and white matter (WM), the hippocampus, and white matter hyperintensities (WMHs). We leverage data from 7 prospective, community-based cohorts across Europe and the United States, all part of the Cross-Cohort Collaboration. The included cohorts were the Age, Gene/Environment Susceptibility-Reykjavik Study, Atherosclerosis Risk in Communities study, Austrian Stroke Prevention Study, Cardiovascular Health Study, Framingham Heart Study, Rotterdam Study, and Study of Health in Pomerania (SHIP-START and SHIP-TREND). Each cohort performed cross-sectional multivariable linear regression analyses, after which estimates were pooled through random-effects meta-analysis. Heterogeneity was assessed by the I2 index (%). Among 10,889 participants (mean age: 66.8 years, range 52.0–76.0; 56.7% women), markers of systolic dysfunction were consistently associated with smaller total brain volume (TBV) (e.g., adjusted standardized mean difference for moderate to severe dysfunction −0.19, 95% CI −0.31 to −0.07, I2 = 20%). Impaired relaxation and restrictive diastolic dysfunction were also associated with smaller TBV (e.g., for impaired relaxation −0.08, 95% CI −0.15 to −0.01, I2 = 32%) and hippocampal volume (−0.18, 95% CI −0.33 to −0.03, I2 = 0%), with similar results for the E/A-ratio. Systolic and diastolic dysfunction was not consistently associated with volume of WMHs. Among 5 cohorts with available data, 302 (3.4%) participants had clinical heart failure, which was associated with smaller brain volumes, particularly in the hippocampus (−0.13, 95% CI −0.23 to −0.02, I2 = 1%). In this large study among community-dwelling adults, subclinical cardiac dysfunction was associated with brain imaging markers of neurodegeneration. These findings encourage longitudinal investigations on the effect of maintaining cardiac function on brain health.