Comparison of ST segment changes on standard and Holter electrocardiogram during exercise testing

Area of Science:

• Cardiology
• Diagnostic Imaging
• Exercise Physiology

Background:

• Standard electrocardiogram (ECG) and Holter monitoring are crucial for diagnosing cardiac ischemia.
• Exercise testing is a common method to elicit ST segment changes indicative of myocardial ischemia.
• Simultaneous comparison of ST segment changes between Holter and standard ECG during exercise is valuable for assessing diagnostic accuracy.

Purpose of the Study:

• To compare ST segment changes recorded simultaneously by Holter monitoring and standard ECG during exercise testing.
• To evaluate the sensitivity of Holter lead CM5 versus standard ECG lead V5 in detecting exercise-induced ST segment depression.

Main Methods:

• 22 patients with chest discomfort and normal resting ECG underwent exercise testing.
• Simultaneous recordings were made using a Del Mar Avionics 445B Holter recorder (lead CM5 and modified lead II) and a standard ECG (lead V5 and modified lead II).
• Bifurcating electrodes ensured identical electrode placement for both systems.

Main Results:

• Seven patients had positive exercise tests by both systems.
• Holter lead CM5 showed greater ST segment depression amplitude than standard ECG lead V5 in 6 of 7 positive cases (mean difference 0.7 mm).
• ST segment depression in lead CM5 ranged from 1-3.5 mm (mean 2.2 mm), while in lead V5 it ranged from 1-2.5 mm (mean 1.5 mm).

Conclusions:

• Holter monitoring with lead CM5 demonstrates higher amplitude ST segment depression compared to standard ECG lead V5 during exercise testing.
• Lead CM5 may offer enhanced sensitivity for detecting exercise-induced myocardial ischemia.
• These findings support the utility of Holter monitoring with specific leads for improved diagnosis of coronary artery disease.