Document Type

Conference Proceeding

Publication Date

5-2-2025

Abstract

A persistent left-sided superior vena cava (PLSVC) is a rare vascular anomaly where the left superior cardinal vein fails to regress during embryogenesis, resulting in an additional venous structure that drains into the right atrium, often via the coronary sinus. It is usually asymptomatic but may be discovered incidentally during imaging or procedures, but its presence can have implications for central venous access and pacemaker placement. Our case features an 82-year-old male with a past medical history of coronary artery disease, remote esophageal cancer, hypertension, hyperlipidemia, and tobacco use disorder, referred to the emergency department from his primary care doctor’s office asymptomatic bradycardia during a routine clinical visit. On arrival, he remained asymptomatic with notable vitals showing hypertension (150/60 mmHg) and bradycardia (heart rate in the 30s). ECG revealed a third-degree heart block, and his physical exam and laboratory findings, including complete blood counts, renal function, and cardiac markers, were unremarkable. Due to the high risk of deterioration, a temporary transvenous pacer (TVP) was placed via the right internal jugular vein, confirmed by chest X-ray, and he was admitted to the cardiac intensive care unit for evaluation by electrophysiology for permanent pacemaker placement. Overnight, the patient accidentally dislodged the TVP wire while scratching his neck. A new TVP was inserted in the right internal jugular vein, but it began losing capture within hours, despite confirmation of correct positioning by chest X-ray and repeated threshold testing. The patient’s complete heart block persisted, raising concerns of lead malfunction or impedance. Transcutaneous pacer pads were used as a backup, but the patient experienced a five-second episode of asystole and cardiac arrest. ACLS protocol was initiated, achieving return of spontaneous circulation within three minutes after one round of CPR and epinephrine. Following this event, a new TVP was successfully placed via the left internal jugular vein, restoring rhythm with overdrive pacing. Interestingly, a follow-up chest X-ray revealed the TVP wire’s anomalous course, confirming placement through a persistent left-sided superior vena cava. The wire traveled via the left-sided SVC into the coronary sinus, then the right atrium, and finally into the right ventricle. Recognizing a PLSVC is crucial due to its implications for central venous access, device placement, and procedural safety. It can alter the expected anatomy, leading to difficulties in advancing catheters or pacemaker leads and increasing the risk of misplacement or vessel injury. Failure to recognize PLSVC can result in procedural complications, such as arrhythmias, venous perforation, or inadequate pacing. Understanding its presence allows clinicians to tailor their approach, use appropriate imaging for guidance, and mitigate potential risks during interventional procedures.

Comments

American College of Physicians Michigan Chapter and Society of Hospital Medicine Michigan Chapter Resident and Medical Student Day, May 2, 2025, Troy, MI

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