In recent decades, the increasing frequency, intensity, and duration of heatwaves generated by climate change has posed significant challenges to public health, particularly in urban areas. Despite extensive research on the impacts of heatwaves on human health, there is still a need for enhanced understanding of how, and to what extent, the spatial attributes of urban environments exacerbate these effects at the very local scale. This research addresses this gap and emphasises the importance of analysing the relationship among urban form, climate and health through high resolution geo-spatial data. By investigating the spatial correlations between geolocated cardiovascular and respiratory emergency calls, the modelled universal thermal climate index (UTCI) and selected socio-demographic factors during the summer of 2022 in Milan, this study aims to enhance our understanding of the complex interaction among heat, the built environment, and specific health outcomes. The findings identify geographical locations where emergency calls occur more frequently and where health concerns emerge during hot spells. Morphological and socio-demographic factors both play a critical role in determining vulnerability to heat stress. The results provide valuable insights for identifying high-risk areas, where tailored interventions in terms of planning, governance and urban design may be implemented to address heat-resilience and health-equity in cities.