U wave inversion during attacks of variant angina.

Area of Science:

• Cardiology
• Clinical Electrophysiology

Background:

• Variant angina, characterized by coronary artery spasm, presents diagnostic challenges.
• Electrocardiogram (ECG) changes during variant angina are crucial for diagnosis but can be variable.

Purpose of the Study:

• To evaluate the diagnostic utility of U wave inversion in variant angina.
• To compare the sensitivity of U wave inversion versus ST segment elevation in diagnosing coronary artery spasm.

Main Methods:

• Sequential 12-lead ECGs were recorded during ergonovine-induced angina in 38 patients with variant angina.
• ECGs were analyzed for ST segment elevation and U wave inversion, particularly in anterior and inferior leads.
• Sensitivity of ECG findings was assessed during acute attacks and recovery phases.

Main Results:

• U wave inversion was observed in 17 patients with anterior ST elevation and 3 with inferior ST elevation.
• In left anterior descending artery spasm, U wave inversion sensitivity (71%) exceeded ST elevation sensitivity (41%) in V5.
• U wave inversion without ST elevation occurred in 35% of patients during attacks and showed high sensitivity (82% in V4, 65% in V5) during recovery.

Conclusions:

• Inverted U waves, particularly without ST segment elevation, are significant indicators in variant angina.
• U wave inversion is a sensitive marker for diagnosing variant angina, especially when monitoring lead V5 or during the recovery phase.