Tehran University of Medical Sciences Case Reports in Clinical Practice 2538-2683 2 1 2017 08 26 24 26 EN Reza Hajizadeh Cardiovascular Research Center AND Department of Cardiology, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran. Bahram Sohrabi Cardiovascular Research Center AND Department of Cardiology, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran. Fariborz Akbarzadeh Cardiovascular Research Center AND Department of Cardiology, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran. Abdolmohammad Ranjbar Cardiovascular Research Center AND Department of Cardiology, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran. 2017 04 07 2017 06 07 Many cardiovascular procedures such as temporary pacemaker insertion, electrophysiological studies, and percutaneous transmitral commissurotomy are carried through inferior vena cava (IVC). Its malformations such as its interruption with azygous/hemiazygous continuation, left-sided IVC, and double IVC can make some difficulties for cardiologists during these procedures. In this case report, we present the case of a 75-year-old male with recurrent episodes of syncope and bradycardia. Due to interrupted IVC, temporary pacing lead was difficultly advanced from the IVC to the accessory hemiazygos vein, left brachiocephalic vein, superior vena cava, right atrium, and right ventricle. Temporary pacemaker insertion is an invasive procedure and should be performed under the guidance of fluoroscopy. However, rarely, IVC malformations such as interrupted IVC make it difficult to do procedure in a short period of time. Rupture of IVC and some complications due to severe bradycardia can be prevented by understanding rare IVC malformations. https://crcp.tums.ac.ir/index.php/crcp/article/view/110 https://crcp.tums.ac.ir/index.php/crcp/article/download/110/70