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A recent study delivers a sobering message: heat exposure can exacerbate heart stress and trigger ischemia in individuals with coronary artery disease (CAD), requiring urgent precautions for vulnerable populations.

Conducted by researchers from the Montreal Heart Institute, the study published on June 10, involved a controlled laboratory experiment encompassing healthy adults and those with CAD. The findings unveiled a concerning trend: even passive heat exposure heightened myocardial blood flow (MBF) in all participants, irrespective of age or health status, imposing significant strain on the heart.

Of particular concern was the observation of asymptomatic heat-induced myocardial ischemia in some CAD patients, underscoring the need for these individuals to prioritize cooling strategies during extreme heat events to mitigate cardiac strain. The study, published in the Annals of Internal Medicine, emphasizes the critical importance of safeguarding high-risk individuals against the adverse effects of heat exposure.

In the experimental setup, comprising 20 healthy young adults, 21 healthy older adults, and 20 older adults with CAD, participants underwent controlled heating until their core temperature rose by 1.5 degrees Celsius (C), with MBF measurements taken at incremental temperature increases.

The researchers discovered a universal increase in MBF among all participants following a 1.5-degree C temperature rise. Alarmingly, imaging evidence revealed asymptomatic heat-induced myocardial ischemia in seven CAD patients, highlighting the vulnerability of this population to heat-related cardiac complications, per Scitech Daily.

In light of these findings, an editorial from the Annals of Internal Medicine and the University of Pennsylvania Perelman School of Medicine underscores the urgency of identifying susceptible individuals, particularly those with obstructive coronary epicardial stenosis or microvascular dysfunction, amidst rising global temperatures. Heat exposure poses a significant risk of supply-demand mismatch in vessels with flow-limiting disease, potentially leading to symptomatic or silent ischemia and heightened cardiovascular events.

The editorial advocates for proactive physician counseling to educate at-risk patients about the dangers of heat exposure, emphasizing the importance of recognizing hyperthermia symptoms and adopting preventive measures to safeguard cardiovascular health.