Persistent second-degree atrioventricular block following adenosine infusion for nuclear stress testing

Area of Science:

• Cardiology
• Nuclear Medicine

Background:

• Nuclear stress testing (NST) utilizes pharmacologic agents like adenosine, dobutamine, and dipyridamole to assess myocardial perfusion.
• These agents are generally well-tolerated, with a low incidence of serious complications during NST.

Observation:

• Adenosine is a potent atrioventricular (AV) nodal inhibitor, capable of inducing transient conduction defects.
• In patients with underlying conduction system disease, adenosine administration during NST may precipitate significant bradyarrhythmias, including heart block.

Findings:

• This report details a case of a 79-year-old male who developed second-degree AV block requiring permanent pacemaker implantation after adenosine infusion for NST.
• Literature review supports an association between adenosine-induced NST and the occurrence of AV block, particularly in susceptible individuals.

Implications:

• Clinicians should exercise caution when administering adenosine for NST in patients with known or suspected conduction system disease.
• Careful patient selection and monitoring are crucial to mitigate the risk of serious cardiac complications during pharmacologic stress testing.