Mitral valve regurgitation and endocarditis triggered by a needle

BACKGROUND: Cardiac foreign bodies are extremely rare in clinical patients, especially when foreign bodies damage the internal structure of the heart coincidentally after they penetrate the heart. CASE PRESENTATION: Here, we report the case of a two-year-old girl whose heart was penetrated by a needle, which triggered mitral valve regurgitation and endocarditis. After a comprehensive inspection, accurate judgment and surgical preparation, we removed the needle and repaired her mitral valve. Fortunately, she recovered postoperatively. CONCLUSION: From this case, we can know that when cardiac foreign bodies are suspected, ultrasound is an important inspection method. Moreover, the approaches for handling each such case are different depending on the associated injuries. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12872-021-02109-z.