A new study conducted by the D-Hygea Lab of the Department of Electronics, Information and Bioengineering at the Politecnico di Milano, in collaboration with the Agenzia Regionale Emergenza Urgenza (AREU), analyzed the impact of heat waves on the cardiovascular health of Milan residents. The results show that in 18 highly vulnerable districts, home to 23% of the city's population, the risk of cardiovascular emergencies increases by 22% during extreme heat days compared to normal days. In contrast, in 20 low-vulnerability districts, the increase in risk is not significant. Among the most vulnerable neighborhoods, with a high percentage of elderly residents, are Buenos Aires - Porta Venezia and Loreto-Casoretto. Districts such as Gorla-Precotto and Porta Magenta, characterized by public drinking fountains and green spaces, on the other hand, are more resilient. A higher proportion of elderly and college-educated residents is associated with increased cardiovascular risk. Conversely, the density of public drinking fountains and a higher percentage of female residents record a lower risk of emergencies during hot weather. The study analyzed 64,881 cardiovascular emergencies recorded between 2017 and 2022, identifying 114 extreme heat days, defined as those with an apparent temperature above the 95th percentile. The hottest day was June 27, 2019, with an average temperature of 36 degrees.