ST depression is a medical finding related to the heart’s electrical activity. Understanding this term can help individuals discuss heart health with their healthcare providers.
Understanding ST Depression
The ST segment is part of the heart’s electrical activity, visualized on an electrocardiogram (ECG). An ECG records electrical signals as they travel through the heart, displaying them as waves and segments. The ST segment is the flat line connecting the QRS complex (ventricular depolarization) to the T wave (ventricular repolarization).
When this segment appears “depressed,” its line is lower than the ECG baseline. This deviation often indicates the heart muscle may not be receiving sufficient blood flow and oxygen. This reduced blood flow is called myocardial ischemia. The electrical signal change reflects the heart muscle’s response to this oxygen lack.
Common Causes and Associated Symptoms
The most frequent cause of ST depression is myocardial ischemia, often resulting from coronary artery disease (CAD). In CAD, arteries supplying blood to the heart muscle narrow or block due to plaque buildup. This restricts blood flow, especially during exertion or stress, leading to oxygen deprivation and ST depression. The severity of ST depression can be influenced by the degree of narrowing and affected heart muscle.
While CAD is the primary cause, other factors can contribute to ST depression. These include certain medications, electrolyte imbalances, or very rapid heart rates. Left ventricular hypertrophy, where the heart muscle thickens, can also affect the ST segment. People with ST depression, especially due to ischemia, might report symptoms like chest pain (angina), shortness of breath, unexplained fatigue, or discomfort radiating to the arm, neck, or jaw.
Diagnostic Approaches
Medical professionals primarily detect ST depression using an electrocardiogram. While an ECG records electrical activity at rest, ST depression often becomes more apparent under stress. Physicians use stress tests to evaluate the heart’s response to increased demand. During an exercise stress test, a person walks on a treadmill or cycles a stationary bike while their ECG is continuously monitored.
If a person cannot exercise, a pharmacological stress test uses medications to simulate exercise effects. ST depression during these tests can indicate underlying issues not evident at rest. Following an initial finding, other diagnostic tools may be used. These include echocardiograms, which use sound waves to image the heart, or cardiac catheterization, an invasive procedure to visualize coronary arteries, to investigate the cause and extent of heart disease.
Interpreting Findings and Management
An ST depression finding indicates potential heart issues, but its full meaning is determined by a healthcare professional. A physician considers this finding with a patient’s health history, reported symptoms, and other diagnostic test results. The presence, magnitude, and characteristics of ST depression provide valuable information for further evaluation.
Management strategies for ST depression depend on its underlying cause and severity. If coronary artery disease is identified, treatment may involve lifestyle modifications like a heart-healthy diet and regular physical activity. Medications might also be prescribed to improve blood flow, manage cholesterol, or control blood pressure. Medical procedures like angioplasty or bypass surgery may be necessary in some instances. Individuals must consult a doctor for personalized advice and a tailored treatment plan.