QT interval prolongation and torsades de pointes unmasked by intracoronary acetylcholine administration

Area of Science:

• Cardiology
• Clinical Electrophysiology
• Pharmacology

Background:

• Coronary artery vasospasm is often diagnosed using intracoronary acetylcholine testing.
• The QT interval, a measure of ventricular repolarization, is crucial for assessing arrhythmia risk.

Observation:

• Intracoronary acetylcholine administration was performed to rule out vasospasms.
• The patient exhibited a normal QT interval prior to the acetylcholine challenge.

Findings:

• Acetylcholine administration unmasked significant QT interval prolongation.
• The unmasked QT prolongation triggered episodes of torsades de pointes, a life-threatening ventricular arrhythmia.

Implications:

• Intracoronary acetylcholine testing can reveal latent cardiac electrical abnormalities.
• This case underscores the importance of monitoring the QT interval during provocative pharmacologic testing.
• Consideration of QT prolongation during acetylcholine challenge is vital for preventing potentially fatal arrhythmias.