The revival of the electrocardiogram in the stress imaging era: what European Society of Cardiology 2024 guidelines say (and don’t say)

An electrocardiogram (ECG) is a vital diagnostic tool used during cardiac imaging stress testing to evaluate the heart’s electrical activity under stress conditions. This combination of ECG and stress imaging testing provides comprehensive insights into cardiac function, particularly in detecting coronary artery disease (CAD) and assessing overall heart health. An ECG continuously monitors the heart’s electrical signals, capturing data on heart rate, rhythm, and electrical conduction patterns. The value of the ECG in this context lies in its ability to detect ischemic changes, which occur when there is insufficient blood flow to the heart muscle due to narrowed or blocked coronary arteries, but also for coronary vasospasm or coronary microvascular disease. Specific ECG changes, such as ST-segment depression or elevation, and the appearance of arrhythmias, can indicate myocardial ischemia. These findings, when correlated with symptoms like chest pain or shortness of breath during the test, may provide strong evidence for CAD even in the absence of diagnostic abnormality of cardiac imaging with regional wall motion or perfusion changes. Additionally, the ECG helps identify other conditions that may manifest under stress, such as arrhythmias or conduction abnormalities, which might not be apparent at rest. The ECG’s role extends beyond diagnosis. It helps stratify patients based on their risk of adverse cardiac events. For example, an abnormal ECG during a negative cardiac stress imaging test can suggest an increased likelihood of coronary calcification or abnormal coronary flow reserve and increased risk in the long term for cardiac events. In summary, the ECG is a valuable component of cardiac imaging stress testing. It provides real-time, non-invasive monitoring of the heart’s electrical activity under stress, aiding in the diagnosis and risk assessment of CAD and other cardiac conditions. This enhances patient management by guiding treatment decisions and preventive strategies.