Medical Bulletin 07/Jul/2025

Hypertrophic cardiomyopathy, one of the most common inherited heart conditions, affects 1 in every 200 to 500 people worldwide and is a leading cause of sudden cardiac death, particularly among young individuals and athletes.

The AI model changes that by harnessing a wide range of patient data, including long-overlooked contrast-enhanced MRI images and full-spectrum electronic health records. These images, while difficult for human doctors to interpret in detail, contain critical patterns of fibrosis—or heart scarring—that are strongly associated with cardiac arrest risk.

Tested against real-world patient data from Johns Hopkins Hospital and the Sanger Heart & Vascular Institute in North Carolina, MAARS achieved 89% overall accuracy and 93% accuracy in patients aged 40 to 60—those most vulnerable to sudden cardiac death. Importantly, the AI model also explains why a patient is high risk, enabling doctors to tailor treatment more precisely.

“Currently we have patients dying in the prime of their life because they aren't protected and others who are putting up with defibrillators for the rest of their lives with no benefit,” said senior author Natalia Trayanova. “We have the ability to predict with very high accuracy whether a patient is at very high risk for sudden cardiac death or not.”

Reference: Changxin Lai, Minglang Yin, Eugene G. Kholmovski, Dan M. Popescu, Dai-Yin Lu, Erica Scherer, Edem Binka, Stefan L. Zimmerman, Jonathan Chrispin, Allison G. Hays, Dermot M. Phelan, M. Roselle Abraham, Natalia A. Trayanova. Multimodal AI to forecast arrhythmic death in hypertrophic cardiomyopathy. Nature Cardiovascular Research, 2025; DOI: 10.1038/s44161-025-00679-1

Can Even Low Levels of Air Pollution Scar the Heart?

A new study published in Radiology, the journal of the Radiological Society of North America (RSNA), has found that prolonged exposure to fine particulate air pollution is associated with early signs of heart damage. Using advanced cardiac MRI, researchers discovered that even low levels of air pollution may contribute to diffuse myocardial fibrosis, a form of scarring in the heart muscle that often precedes heart failure.

Cardiovascular disease remains the leading cause of death worldwide, and while prior research has linked poor air quality to increased risk of heart attacks and other cardiovascular issues, the biological mechanisms behind this risk have remained unclear.

To explore this, the researchers used cardiac MRI, a noninvasive imaging method, to quantify myocardial fibrosis in relation to long-term exposure to PM2.5—fine particulate matter less than 2.5 micrometers in diameter, commonly emitted from vehicle exhaust, industrial activity, and wildfire smoke. The study included 201 healthy participants and 493 individuals with dilated cardiomyopathy, a condition that weakens the heart's ability to pump blood.

The findings revealed that both healthy individuals and patients with heart disease who had higher long-term exposure to PM2.5 showed increased levels of myocardial fibrosis. The strongest associations were found in women, smokers, and individuals with hypertension

The study suggests that integrating a patient’s air pollution exposure history into clinical evaluations could improve risk assessments and help address related health disparities.

“Public health measures are needed to further reduce long-term air pollution exposure,” said senior author Dr. Kate Hanneman, from the Department of Medical Imaging at the University of Toronto and University Health Network, emphasizing that current pollution levels—even those within global guidelines—may still pose health risks. The research also highlights the vital role radiologists can play in identifying environmental impacts on human health through imaging.

Reference: Jacques Du Plessis, Chloe DesRoche, Scott Delaney, Rachel C. Nethery, Rachel Hong, Paaladinesh Thavendiranathan, Heather Ross, Felipe Castillo, Kate Hanneman. Association between Long-term Exposure to Ambient Air Pollution and Myocardial Fibrosis Assessed with Cardiac MRI. Radiology, 2025; 316 (1) DOI: 10.1148/radiol.250331

Decades After Diagnosis, Childhood Cancer Survivors Still Vulnerable to Severe COVID

A new study from Karolinska Institutet, published in The Lancet Regional Health – Europe, reveals that individuals who survived cancer during childhood are at a significantly higher risk of developing severe COVID-19 even decades after their diagnosis and treatment.

In this large registry-based study, researchers set out to examine how adult survivors of childhood cancer in Sweden and Denmark were affected during the COVID-19 pandemic.

The study included data from more than 13,000 people who were diagnosed with cancer before the age of 20 and were at least 20 years old when the pandemic began. Their outcomes were compared with siblings and randomly selected individuals from the general population matched by gender and year of birth.

The results showed that survivors of childhood cancer were less likely to contract COVID-19, possibly due to more cautious behavior. However, if they did become infected, they were 58% more likely to develop severe illness. Severe COVID-19 was defined in the study as hospitalization, admission to intensive care, or death related to the infection.

The elevated risk was especially pronounced during waves driven by highly transmissible variants like Alpha and Omicron. Differences in public health responses also played a role—Sweden’s strategy of relying on recommendations, rather than strict restrictions like those seen in Denmark, appeared to correlate with higher risks for survivors.

“Our results suggest that childhood cancer survivors should be considered a risk group in future pandemics or other health crises. This could involve prioritising them for vaccination or offering special protection during periods of high transmission,” said Javier Louro, postdoctoral researcher at the Institute of Environmental Medicine at Karolinska Institutet and first author of the study.

Reference: “COVID-19 infection and severity among childhood cancer survivors in Denmark and Sweden: a register-based cohort study”, Javier Louro, Christina-Evmorfia Kampitsi, Hanna Mogensen, Friederike Erdmann, Karin Modig, Anna Nilsson, Mats Heyman, Henrik Hasle, Anja Krøyer, Line Kenborg, Henrik Hjalgrim, Maria Feychting, Giorgio Tettamanti, The Lancet Regional Health – Europe, online July 4, 2025, doi: 10.1016/j.lanepe.2025.101363