Lay summary
Cardiovascular disease is a leading cause of death and illness in Aotearoa New Zealand. Heart attacks and other cardiovascular events often occur without warning, particularly in individuals classified as low or intermediate risk by existing prediction tools. This underscores the need for new, innovative biological indicators, called biomarkers, to improve these tools and better identify individuals at risk. Recent advances in detecting DNA modifications in blood have opened the door to a promising new set of potential biomarkers. Here, we will investigate oxidised mitochondrial DNA, which is released into the bloodstream when the heart is stressed or damaged. By measuring oxidised mitochondrial DNA in a heart attack model and also in blood samples from healthy volunteers who later experienced unexpected heart events, we aim to determine whether it can serve as an early warning signal to identify at-risk individuals who might otherwise be overlooked.