An electrocardiogram (ECG or EKG) records the heart’s electrical activity, helping medical professionals assess heart health. This non-invasive test translates the heart’s electrical signals into a visual tracing. One specific finding, “ST elevation,” holds significant meaning and requires immediate medical attention due to its potential implications for cardiac well-being.
What is ST Elevation on an ECG
The heart generates electrical impulses that cause its muscles to contract and pump blood. An ECG captures these signals, displaying them as waves and segments. A typical ECG tracing includes a P wave, representing the contraction of the heart’s upper chambers, and a QRS complex, indicating the electrical activity as the heart’s main pumping chambers contract. A T wave follows, showing the recovery phase of these chambers.
The ST segment is the flat line between the end of the QRS complex and the beginning of the T wave. This segment represents the period when the heart’s lower chambers are fully contracted but not yet repolarizing. When this segment appears “elevated” above the baseline on the ECG tracing, it signifies ST elevation. This deviation from the normal baseline indicates an electrical abnormality within the heart.
ST Elevation and Heart Attack
ST elevation most commonly indicates an acute myocardial infarction, or heart attack. Specifically, it points to ST-Elevation Myocardial Infarction (STEMI), which occurs when a coronary artery becomes completely blocked. This blockage prevents oxygen-rich blood from reaching heart muscle, leading to damage.
The ST elevation occurs because affected heart muscle cells, deprived of blood flow, cannot generate enough energy to maintain their normal electrical state. This leads to an “injury current” where electrical charge differences develop between the ischemic (oxygen-deprived) and non-ischemic areas of the heart. This electrical imbalance causes the ST segment to shift upward, indicating severe myocardial injury.
A STEMI is a life-threatening condition that requires urgent intervention. Symptoms often include chest pain, which may be described as pressure, tightness, or a crushing sensation, sometimes radiating to the jaw, neck, back, or arms. Other symptoms can include shortness of breath, sweating, nausea, or dizziness. Recognizing these symptoms and the potential for ST elevation is important for timely medical response.
Other Conditions Causing ST Elevation
While a heart attack is the most concerning cause, ST elevation can also be present in other conditions. Not all ST elevation signifies a heart attack, though immediate medical evaluation remains necessary. For instance, pericarditis, an inflammation of the sac surrounding the heart, can cause widespread ST elevation.
Early repolarization, a benign variant frequently observed in healthy individuals, particularly younger, athletic people, is another common non-ischemic cause. Brugada syndrome, a rare genetic disorder affecting the heart’s electrical activity, can also manifest with specific patterns of ST elevation, primarily in certain chest leads. Other less common causes include bundle branch blocks or some neurological events. Any new ST elevation warrants prompt assessment by medical professionals to determine the underlying issue.
Next Steps After Detecting ST Elevation
When ST elevation is detected on an ECG, it triggers an emergency medical response. The immediate goal is to determine if a heart attack is occurring and, if so, to restore blood flow to the heart muscle quickly. Confirming tests often include blood tests to measure cardiac enzymes, specifically troponin, which are proteins released into the bloodstream when heart muscle is damaged. Elevated troponin levels strongly support a heart attack diagnosis.
An echocardiogram (ultrasound of the heart) may also assess heart function and identify areas of muscle damage. If a heart attack (STEMI) is confirmed, immediate interventions are typically initiated. The primary treatment often involves percutaneous coronary intervention (PCI), commonly known as angioplasty, where a catheter is used to open the blocked artery and often place a stent. In situations where immediate PCI is not feasible, clot-busting medications, called thrombolytics, may be administered to dissolve the blood clot and restore blood flow. Timely medical care is essential, as rapid intervention can limit heart muscle damage and improve patient outcomes.