# Cardiac Arrest During a Ferric Derisomaltose Infusion Followed by Complete Heart Block: A Case Report

## TL;DR

An elderly man experienced cardiac arrest during a ferric derisomaltose infusion, leading to complete heart block and requiring a pacemaker.

## Contribution

This is the first reported case linking ferric derisomaltose infusion to acute cardiac events requiring pacing.

## Key findings

- A patient developed cardiac arrest and complete heart block six minutes into a ferric derisomaltose infusion.
- The patient required transcutaneous pacing and vasopressor administration during stabilization.
- A permanent pacemaker was successfully implanted, and the patient was discharged without complications.

## Abstract

Ferric derisomaltose is the newest available parenteral iron formulation. Studies have demonstrated a good safety profile with improved tolerability compared to alternative parenteral iron formulations. To date there have been no reported acute, life-threatening cardiac events associated with ferric derisomaltose.

An 86-year-old male who had previously tolerated routine iron infusions received a first dose of ferric derisomaltose at an outpatient infusion clinic. Six minutes into the infusion the patient became unresponsive with no palpable pulse. Return of spontaneous circulation was achieved after two minutes of chest compressions. Electrocardiogram showed complete heart block requiring transcutaneous pacing and vasopressor administration. The patient was transferred to the emergency department for stabilization and then admitted to the cardiac intensive care unit. During admission, the patient received a dual-chamber, permanent pacemaker without complication and was ultimately discharged.

It may be reasonable to consider parenteral iron as a toxicological etiology for patients presenting with complete heart block temporally associated with parenteral iron administration, particularly in patients with underlying conduction abnormalities.