The physiological problem is well established but often underestimated. Extreme heat is not simply a matter of discomfort; it places considerable stress on the cardiovascular system. As ambient temperatures rise, the body must dissipate heat by increasing blood flow to the skin and by sweating, which raises heart rate and cardiac output while reducing blood pressure through vasodilation. For a healthy heart this is a manageable challenge, but for a heart weakened by failure, constrained by coronary disease, or destabilised by arrhythmia, the added workload can tip the balance toward decompensation, myocardial ischaemia, dangerous rhythm disturbances or death. Dehydration thickens the blood and increases the risk of clotting, while excessive fluid intake or impaired regulation can lead to overhydration and dangerous dilution of electrolytes. Medications that many cardiac patients take, including diuretics, beta-blockers, ACE inhibitors and other antihypertensives, can further complicate how the body copes with heat, affecting sweating, blood pressure regulation and fluid balance.

Dr Georgia Chaseling of the University of Sydney, an author of the report, explained the motivation behind the work. She noted that while researchers already understand that extreme heat increases the risk of illness and death in cardiovascular patients, understanding the problem is only the first step. Doctors and other healthcare professionals, she said, need practical guidance on what they can actually do to protect their patients. The report was written to translate the scientific evidence into usable advice covering the entire pathway of care: identifying vulnerable patients, preparing them for extreme heat, managing their medications, advising on hydration and cooling, monitoring them during hot weather, adapting cardiac rehabilitation and exercise, and continuing surveillance after a heatwave has passed.

A cornerstone of the report is the concept of the individual heat plan. Because vulnerability varies enormously from patient to patient, the authors argue that clinicians should know who is at risk before periods of extreme heat occur, discuss personalised heat-management plans with them, and consider how each person’s illness, medication regimen, hydration needs and living circumstances shape their risk. An elderly heart failure patient living alone on the top floor of an uninsulated apartment building faces a very different threat profile from a younger, fitter patient with well-controlled hypertension, and the plan must reflect that reality. The report frames this as anticipatory cardiovascular care, embedding heat risk into the same preventive framework already used for smoking, diet, blood pressure and cholesterol.

The recommendations extend well beyond the clinic. Extreme heat can sharply increase demand on emergency departments, hospitals, primary care services, home care and social services, and the report argues that health systems therefore need formal heat action plans, adequate surge capacity and resilient infrastructure. Hospitals should be prepared for waves of heat-related admissions, with staffing, bed capacity and cooling arrangements that can flex when temperatures spike. Proactive outreach is essential to reach vulnerable people who may be socially isolated or have limited access to cooling, since isolation itself is a known risk factor for heat deaths. Achieving this, the authors say, will require coordination between healthcare providers, emergency services, public health agencies and local authorities, so that warnings, cooling resources and clinical follow-up reach the people who need them most.

Some of the most concrete suggestions concern home-based care. The report details the need for proactive home healthcare during heatwaves, with visiting services monitoring patients and providing cooling resources such as fans, ensuring suitable storage for medications that may degrade in high temperatures, and watching for early signs of both dehydration and overhydration in vulnerable patients. These measures may sound modest, but they target precisely the window in which deterioration can be caught and reversed before it becomes an emergency admission or a fatality. The report’s authors present such interventions as part of a spectrum of preventable harm: with the right heat plans tailored to each patient, deaths that currently occur in heatwaves need not happen.

The report also provides population-specific recommendations that clinicians can apply directly. In patients with heart failure, clinicians should carefully monitor hydration, body weight, electrolytes and medication use, since the delicate fluid balance these patients maintain can be disrupted quickly by heat and sweating. In patients with arrhythmias, particular attention should be paid to changes in the body’s salt and mineral balance, hydration status, and symptoms such as palpitations, dizziness and excessive fatigue, all of which may signal that heat stress is destabilising the heart’s electrical system. For people with hypertension, home blood pressure monitoring and the prevention of heat-related hypotension and falls become particularly important, because vasodilation and medication effects can combine to drop blood pressure to dangerous levels, increasing the risk of syncope and injury.

For patients and their families, the report carries an equally important set of messages. Co-author Professor Philip Moons of the University of Leuven in Belgium emphasised that the aim is to make preparedness for extreme heat part of routine cardiovascular care, and that as heat extremes become more frequent and intense, no one should wait until a heatwave occurs to start thinking about how to protect patients. The most important message for families, he said, is that the cardiovascular risks associated with extreme heat are at least partly preventable. People with cardiovascular disease should recognise that hot weather may require changes to their usual routines, closer attention to hydration and cooling, and careful monitoring of blood pressure and heart rate. They should also know when symptoms such as dizziness, confusion, worsening breathlessness or palpitations require medical attention. Crucially, patients should not stop or change their cardiovascular medication on their own because of hot weather, a common and potentially dangerous mistake.

The report, published on behalf of the ESC’s Association of Cardiovascular Nursing & Allied Professions, the Association for Acute CardioVascular Care, the European Association of Preventive Cardiology, the Heart Failure Association and the European Heart Rhythm Association, together with the ESC Council on Hypertension, the ESC Council on Stroke and the ESC Working Group on Cardiovascular Pharmacotherapy, is candid about the limits of current knowledge. The authors say more research is needed on why some patients appear more vulnerable to heat than others, a question with direct clinical consequences for how heat plans are targeted. They also highlight a striking gap in the evidence base: most research on how heat affects common cardiovascular medications comes from studies conducted in young, healthy individuals, rather than the typical patients who actually take these drugs, people who are often older, frailer and living with multiple other health conditions. Filling these gaps, the authors argue, is essential if guidance is to keep pace with a warming climate.

What emerges from the report is a vision of climate-adapted cardiology in which extreme heat is treated as a clinical variable as routine as blood pressure or cholesterol. The stakes are enormous: heatwaves are becoming more frequent, more intense and longer-lasting across Europe and much of the world, and the population of older adults with cardiovascular disease continues to grow. The report’s authors make clear that the tools needed to save lives already exist, from fans and medication storage advice to hospital surge planning and personalised heat plans. What has been missing is the systematic integration of these tools into everyday cardiovascular practice. If the report’s recommendations are adopted, the next heatwave could find patients prepared, clinicians vigilant and health systems ready, rather than scrambling to respond once the deaths have already begun.

Subject of Research: Protecting people with cardiovascular disease from heat-related illness and death during heatwaves

Article Title: From distributing fans to preparing hospitals for heat surges: report shows how we must protect people living with heart disease in heatwaves

Article References: From distributing fans to preparing hospitals for heat surges: report shows how we must protect people living with heart disease in heatwaves. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: heatwaves, cardiovascular disease, European Society of Cardiology, European Heart Journal, heart failure, hypertension, arrhythmias, heat plans, hospital surge capacity, dehydration, home healthcare, climate change

The European Cardiovascular Health Data and AI Network, known as CHAIN, has been launched with €20 million in funding from the EU4Health Programme and is coordinated by the European Society of Cardiology (ESC). The 36-month project brings together a consortium of 53 partners from 20 European countries, spanning universities and research centres, hospitals and clinical networks, technology companies, national ministries of health and patient organisations. Its central ambition is to build a federated ecosystem for the safe, effective and scalable adoption of AI in cardiovascular care, aligned with the European Health Data Space, the EU’s ambitious framework for cross-border health data sharing.

The problem CHAIN seeks to solve is well documented. AI models capable of detecting heart disease earlier, stratifying patient risk more accurately and supporting clinical decisions have proliferated in the scientific literature, yet their uptake in routine care remains patchy and inconsistent. Standardised validation mechanisms are largely lacking, meaning hospitals and health authorities often have no reliable way of knowing which algorithms perform as advertised, for which patient populations, and under which clinical conditions. The result is a landscape in which promising tools stall at the pilot stage while unvetted ones occasionally reach clinics without adequate scrutiny.

CHAIN’s technical answer to this challenge rests on two pillars: a federated data infrastructure and a system of validation credentials. Rather than centralising sensitive patient records, the project will securely connect hospitals, health data hubs and disease registries across Europe in a federated architecture, allowing AI solutions to be tested, validated and deployed at scale while data remain within their originating institutions. This approach, which aligns with the privacy-preserving principles underpinning the European Health Data Space, enables algorithms to be evaluated on diverse, real-world populations drawn from multiple healthcare systems, a critical step for detecting the biases and performance gaps that often emerge when models trained in one setting are applied in another.

The second pillar is a European repository of validated AI solutions, each accompanied by what the project calls an ‘AI passport’. These passports will document a model’s performance, safety and suitability for clinical use, giving healthcare authorities, hospital administrators and practicing clinicians clear, standardised evidence on which solutions work, for whom and in which settings. In an era when clinicians and patients alike are wary of opaque algorithmic tools, the passports are designed to function as a trusted seal of approval, helping decision-makers distinguish genuinely useful innovations from overhyped ones. Professor Folkert Asselbergs of Amsterdam University Medical Centre, CHAIN’s scientific coordinator and chair of the ESC AI Gateway, emphasised that in an era of misinformation, patients and healthcare professionals are looking to medical societies to provide a framework for implementing trusted solutions that add real value beyond what is currently available.

To prove the framework works in practice, CHAIN will implement six real-world use cases across 13 countries, deliberately chosen to cover the full continuum of cardiovascular care. The use cases span risk stratification, early disease detection, clinical decision support and the management of complex cardiovascular conditions, ensuring that the validation and deployment mechanisms are tested across different healthcare settings, from large academic centres to smaller regional hospitals. This breadth matters: an AI tool that performs well in a well-resourced Dutch university hospital may fail in a rural clinic in eastern Europe, and the project’s multi-country design is intended to surface such disparities before tools are scaled.

The initiative does not start from scratch. CHAIN builds on the ESC’s EuroHeart registry network, which already unifies 18 ESC member countries with standardised data on cardiovascular care and outcomes, providing tools that help countries monitor results, compare practices and drive sustainable improvements. It will also seek synergies with a constellation of existing EU projects, including EUCAIM, COMPASS AI, AI4HF, DataTools4Heart, EHDEN, JACARDI, TEHDAS2 and Xt-EHR, an effort to maximise complementarities and avoid duplicating infrastructure that Europe has already invested in. The project is explicitly positioned as a key implementation vehicle for the EU Safe Hearts Plan, in particular its flagship initiative on innovation and integration of AI and digital technologies in cardiovascular healthcare.

Timing is a central theme of the launch. CHAIN arrives just as the European Health Data Space, the EU’s landmark AI Act, and an evolving regulatory framework for medical products, spanning pharmaceutical, medical device and in vitro diagnostic legislation, are reshaping how AI is developed, evaluated and deployed across European healthcare. Navigating this regulatory landscape is one of the project’s implicit challenges: any AI tool validated through CHAIN will need to satisfy not only clinical evidence standards but also the transparency, safety and human-oversight requirements that the AI Act imposes on high-risk medical applications. By building governance, evaluation and scale-up mechanisms into its core design, the consortium hopes to create a template that regulators, industry and health systems can adopt more widely.

The political weight behind the project is considerable. Olivér Várhelyi, the EU Commissioner for Health and Animal Welfare, framed the challenge bluntly, saying the question is no longer simply what AI can do, but how to make it work safely and effectively for patients and health professionals in everyday healthcare, and that this is where CHAIN can make a real difference. Professor Cecilia Linde, President of the ESC and a cardiologist at the Karolinska Institute in Sweden, struck a similar note, arguing that the need to act is critical given that one in three deaths in Europe is caused by cardiovascular disease, and describing CHAIN as an effort to turn the promise of AI into better cardiovascular health for everyone by helping trusted innovations reach patients safely and equitably.

Over the next three years, the consortium hopes to deliver a strategic roadmap for scaling AI adoption in cardiology across Europe, one that Professor Asselbergs says will benefit research and industry through shared infrastructure and standards, while validated decision-support tools help reduce the burden on overstretched healthcare systems. The ultimate measure of success, he argues, will be clinical: trustworthy tools that translate into earlier, more accurate diagnosis and safer, more personalised care for patients. If CHAIN succeeds, it could offer something Europe has lacked so far, a coherent, continent-scale pathway for moving AI in medicine from promising publications to measurable patient impact, and a model that other fields of medicine, from oncology to neurology, may soon seek to replicate.

Subject of Research: A European initiative to validate and scale artificial intelligence for cardiovascular disease prevention, detection and treatment

Article Title: From promise to patient impact: New European initiative aims to accelerate AI in cardiovascular care

Article References: From promise to patient impact: New European initiative aims to accelerate AI in cardiovascular care. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: artificial intelligence, cardiovascular disease, CHAIN, European Society of Cardiology, EU4Health, European Health Data Space, AI validation, federated data, clinical decision support, health data infrastructure, AI passports, digital health