What Are the Typical ECG Findings During an Angina Attack?

During an episode of angina, the most characteristic electrocardiogram (ECG) finding is dynamic ST-T segment changes. These changes are typically transient, meaning they do not last for a long time, and may involve either ST-segment elevation or depression. The specific ECG pattern can vary depending on whether the angina is occurring or subsiding, which means the appearance of the ECG can change as the patient's symptoms evolve.

Understanding ST-T Segment Changes

One of the key features of angina-related ECG changes is their dynamic nature. For example, during an angina attack, the ST segment may shift—either upwards or downwards—reflecting the heart's response to reduced blood flow. Once the episode resolves and blood flow returns to normal, the ECG often reverts to its baseline pattern. This transient behavior makes it difficult to detect angina-related abnormalities when the patient is not experiencing symptoms.

Special Considerations in Patients with Pre-existing T-Wave Inversion

In patients who have a history of T-wave inversion, an angina episode can sometimes produce a phenomenon known as pseudonormalization. This occurs when the previously inverted T-waves appear upright during the attack, mimicking a normal ECG pattern. This misleading change underscores the importance of understanding a patient's baseline ECG and medical history when interpreting results during an angina episode.

Diagnostic Challenges During Angina-Free Periods

Because angina-related ECG changes are often fleeting, they can be difficult to capture during periods when the patient is asymptomatic. To overcome this diagnostic challenge, healthcare providers may use alternative testing methods. These include stress testing, Holter monitoring (continuous ECG recording), coronary angiography, and coronary computed tomography angiography (CTA). These tools help identify underlying coronary artery disease and confirm the presence of angina even when the resting ECG appears normal.