Zafar H, Hassanzai FU, Mansoor F, Hussain SS. Persistent left superior vena cava draining into the left atrium presenting as secondary polycythaemia: a case report. J Pak Med Assoc [Internet]. 2026 Nov. 1 [cited 2026 Nov. 1];76(11):1947-9. Available from: https://www.jpma.org.pk/index.php/public_html/article/view/30312