Australian study reveals that many post-COVID-19 individuals develop cardiac function impairment

Long COVID, a condition where symptoms persist or arise months after the initial COVID-19 infection, has been a growing area of concern. While respiratory symptoms like shortness of breath and fatigue are common, new research suggests that the heart may also bear the long-term brunt of the virus.
 
Researchers from several leading institutions, including the Baker Heart and Diabetes Institute, University of Melbourne, Royal Hobart Hospital, and Menzies Institute for Medical Research in Australia, conducted a groundbreaking study to investigate the cardiac function and overall fitness levels in individuals suffering from Long COVID. This Medical News report sheds light on how the heart is affected by Long COVID and what this might mean for patients’ daily lives.
 
What Did the Study Investigate?
The primary aim of the study was to compare heart function between individuals with Long COVID and a control group of non-infected individuals from the same community. To ensure accuracy, the researchers utilized advanced echocardiography to assess heart structure and function, particularly focusing on global longitudinal strain (GLS) - a measure of the heart’s systolic function.
 
Additionally, they evaluated the participants' functional capacities through both subjective methods like the Duke Activity Status Index (DASI) and objective assessments such as the 6-minute walk test (6MWT).
 
A key aspect of the research was the comparison between 190 Long COVID patients and 979 non-COVID individuals. These participants were carefully matched based on factors like age and pre-existing health conditions, such as diabetes and hypertension, to ensure that the only significant variable was the history of COVID-19 infection.
 
Heart Function in Long COVID Patients: The Results
The study revealed several important findings regarding the heart health of Long COVID patients. One of the most significant results was the discovery that individuals with Long COVID showed subtle but notable differences in heart function compared to the control group.

-Subclinical Heart Dysfunction: Researchers found that patients with Long COVID had lower global longitudinal strain (GLS), a measure of how efficiently the heart muscle contracts. On average, the GLS was 18.5%, compared to 19.3% in the control group. While these numbers might seem small, they suggest a subtle reduction in heart function.
 
-Increased Risk of Abnormal GLS: Approximately 13% of Long COVID patients had abnormal GLS readings (<16%), compared to only 8% in the control group. This means that those with Long COVID were more likely to experience impaired systolic function, a key indicator of heart disease risk. The researchers noted that this association was independent of other common risk factors like age, obesity, and diabetes.
 
-Altered Heart Dimensions: While other aspects of heart function, such as diastolic parameters (how the heart relaxes between beats), were not significantly different, the Long COVID group had noticeable differences in left ventricular (LV) dimensions. The LV mass index and posterior wall thickness were greater in the Long COVID group, suggesting a subtle structural change in their hearts.
 
Interestingly, while these heart impairments were observed, they did not fully explain the significant drop in functional capacity seen in Long COVID patients. This finding suggests that while the heart is affected, other factors, such as fatigue or lung function, might also play a critical role in the daily limitations faced by these patients.
 
Reduced Physical Fitness in Long COVID Patients
The study also explored the physical fitness of Long COVID patients compared to the control group, and the results were striking:
 
-Severe Decline in Fitness Levels: An overwhelming 72% of Long COVID patients performed below 85% of the predicted metabolic equivalent (MET) on the DASI, a measure of how well they could perform daily physical tasks. This was in stark contrast to just 5% of the control group.
 
-Shorter Walking Distance: The 6-minute walk test also showed a significant reduction in functional capacity. On average, Long COVID patients walked 506 meters, while the control group covered 561 meters in the same time. Even though both groups were walking within the normal range for their age, the difference highlighted the physical limitations experienced by Long COVID patients.
 
What’s particularly interesting is that while Long COVID patients had measurable heart impairments, the correlation between these impairments and their reduced functional capacity was weak. This suggests that other factors, such as lingering fatigue, muscle weakness, or lung dysfunction, might be contributing to their reduced ability to perform everyday tasks.
 
What Does This Mean for Long COVID Patients?
These findings are crucial because they suggest that Long COVID’s effects on the heart, though subtle, could be long-lasting. The study indicates that about one in ten Long COVID patients experience abnormal heart function, even if they did not have severe COVID-19 symptoms initially.
 
However, it’s important to note that the impaired heart function alone doesn’t seem to account for the severity of functional limitations. This finding opens the door to more complex explanations for Long COVID symptoms, possibly involving multiple organ systems, including the lungs, muscles, and nervous system.
 
The study’s authors emphasize the need for comprehensive care for Long COVID patients, including heart monitoring and rehabilitation programs. Although the heart impairments were mild, they could indicate a greater risk for future heart problems, particularly if other risk factors, such as diabetes or high blood pressure, are present.
 
Conclusion: More Than Just a Heart Problem
In conclusion, this study adds to the growing body of evidence that Long COVID affects more than just the lungs or immune system. It also shows that the heart can suffer lasting damage, even if it’s not immediately obvious. Long COVID patients are more likely to experience subtle changes in heart function, such as reduced GLS, and they tend to have lower physical fitness levels compared to their non-COVID peers.
 
However, the heart is only one piece of the puzzle. While these findings are significant, they don’t fully explain the persistent fatigue and reduced functional capacity seen in Long COVID patients. Other factors, like psychological effects (e.g., depression) and muscle weakness, may also be at play.
 
Given these complex findings, the researchers suggest that Long COVID patients should receive multidisciplinary care, including cardiology evaluations, physical rehabilitation, and mental health support. By addressing all aspects of the condition, healthcare providers can help Long COVID patients recover more fully and reduce their risk of future heart problems.
 
The study findings were published in the peer-reviewed Journal of the American Society of Echocardiography.
https://www.sciencedirect.com/science/article/pii/S0894731724004528
 
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