An echocardiogram, often called an echo, uses sound waves to create moving pictures of the heart. This non-invasive test helps assess the heart’s structure and how well it functions. While an echocardiogram is a valuable tool for evaluating heart health, it does not directly visualize blocked arteries. Instead, it can reveal the effects blockages might have on the heart muscle and its pumping ability.
What an Echocardiogram Shows
An echocardiogram provides detailed insights into the heart’s internal components, offering a comprehensive view of its mechanics. It visualizes the heart’s four chambers and the valves that regulate blood flow between them, assessing their size and thickness for any enlargement or weakening.
Beyond structure, an echo evaluates the heart’s pumping strength, known as ejection fraction, which indicates how much blood is pumped out with each beat. It also identifies wall motion abnormalities, areas of the heart muscle that do not move or contract properly. Such abnormalities can indirectly suggest reduced blood flow, potentially due to coronary artery blockages. The test can also detect problems with heart valves, such as narrowing or leaking, and fluid accumulation around the heart.
Why Echocardiograms Don’t Directly Show Blockages
Standard echocardiograms do not directly show blockages within the coronary arteries because these arteries are typically small and located on the surface of the heart. The ultrasound technology used in a standard echo is designed to image larger heart structures like the chambers and valves, and to assess blood flow patterns within them. Visualizing the narrow, winding coronary arteries with sufficient detail to detect plaque buildup presents a significant challenge for this imaging modality.
While an echo can show the impact of blockages on the heart muscle, such as areas of weakened contraction or damage from a prior heart attack, it cannot directly display the plaque causing the narrowing. It focuses on the heart’s functional response to issues rather than directly imaging the coronary arteries. This distinction is important for understanding the specific diagnostic capabilities and limitations of an echocardiogram.
Diagnosing Blocked Arteries
When blocked arteries are suspected, specific tests directly visualize the coronary arteries. A coronary angiogram, also known as cardiac catheterization, is a definitive test for identifying narrowed or blocked coronary arteries. This invasive procedure involves inserting a thin, flexible tube into a blood vessel, typically in the wrist or groin, and guiding it to the heart. A contrast dye is injected, and X-ray images reveal blood flow through the arteries and pinpoint blockages.
Computed Tomography Angiography (CT Angiography or CCTA) is a non-invasive option. This test uses specialized X-ray technology and contrast dye to create detailed, 3D images of the heart and its blood vessels, showing plaque buildup and narrowing. CT angiography is useful for detecting coronary artery disease and evaluating its extent.
Stress tests assess blockages by evaluating the heart’s response to demand. These tests involve physical exercise or medication to simulate exercise. A stress echocardiogram takes ultrasound images before and immediately after exercise. Comparing these images identifies heart muscle areas that do not function properly under stress, suggesting reduced blood flow due to narrowed arteries.
Other stress tests, like nuclear stress tests, inject radioactive material to visualize blood flow at rest and during activity. Test choice depends on individual symptoms, risk factors, and diagnostic needs.