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QT interval prolongation and torsades de pointes unmasked by intracoronary acetylcholine administration
M Chinushi1, I Nakagawa, T Hori
1First Department of Internal Medicine, Niigata University School of Medicine, Japan. chinushi@med.niigata-u.ac.jp
Pacing and Clinical Electrophysiology : PACE
|November 15, 2001
Insights
Intracoronary acetylcholine challenge revealed a prolonged QT interval and torsades de pointes in a patient. This occurred despite a normal QT interval at rest, highlighting a potential diagnostic challenge.
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.
Abstract:
Intracoronary acetylcholine administration, which was performed to exclude vasospasms, unmasked an abnormal QT interval prolongation and initiated torsades de pointes in a patient with normal QT interval at rest.