BACKGROUND: Cardiovascular diseases remain the foremost global cause of death. The COVID-19 pandemic has strained health-care systems, leading to delays in essential medical services, including treatment for cardiovascular diseases. We aimed to examine the impact of the pandemic on delayed cardiovascular care in Europe. METHODS: In this systematic review, we searched PubMed, Embase, and Web of Science for peer-reviewed and published quantitative studies in English from Nov 1, 2019, to Sept 18, 2022, that addressed pandemic-induced delays in cardiovascular disease care for adult patients in Europe. Data appraisal, extraction, and quality assessment were done by two reviewers using the 14-item QualSyst tool checklist. We extracted summary patient-level data from the studies, including around 3·5 million patients. Evaluated outcomes included changes pre-March 2020 and during the COVID-19 pandemic in hospital admissions, mortality rates, medical help-seeking delays post-symptom onset, treatment initiation delays, and treatment procedure counts. The protocol is registered on PROSPERO (CRD42022354443). FINDINGS: Of the 132 included studies (20% from the UK), all were observational retrospective, with 87% focusing on the first wave of the pandemic. Results were categorised into five disease groups: ischaemic heart diseases, cerebrovascular diseases, cardiac arrests, heart failures, and others. Hospital admissions showed significant decreases around the ranges of 12-66% for ischaemic heart diseases, 9-40% for cerebrovascular diseases, 9-66% for heart failures, 27-88% for urgent and elective cardiac procedures, and an increase between 11-56% for cardiac arrests. Mortality rates were significantly higher during the pandemic, ranging between 1-25% (vs 16-22% before the pandemic) for ischaemic heart diseases and 8-70% (vs 8-26% before the pandemic) for cerebrovascular diseases. Only one study ranked low in quality. INTERPRETATION: The pandemic led to reduced acute CVD hospital admissions and increased mortality rates. Delays in seeking medical help were observed, while urgent and elective cardiac procedures decreased. Policymakers and health-care systems should work together on implementing adequate resource allocation strategies and clear guidelines on how to handle care during health crises, reducing diagnosis and treatment initiation delays, and promoting a healthy lifestyle. Future studies should evaluate the long-term impact of pandemics on delayed CVD care, and the health-economic impact of COVID-19. FUNDING: Belgian Science Policy Office.