Echocardiography

Overview of the Procedure

Cardiac ultrasound (Echocardiography) is a non-invasive imaging technique that uses high-frequency sound waves to produce real-time images of the heart's structure and function. It is primarily used to assess myocardial performance, valvular function, atrial and ventricular function, and blood flow dynamics. This examination involves no radiation exposure and is suitable for all age groups, including pregnant women and infants.

The core value lies in providing dynamic three-dimensional visualization data to assist in diagnosing the causes and severity of heart diseases. Physicians can observe ventricular contractility, valvular stenosis or regurgitation through imaging, and evaluate the effectiveness of treatments. Results are often combined with other diagnostic tools such as electrocardiograms and magnetic resonance imaging to form a comprehensive cardiac assessment system.

Types and Mechanisms of the Examination

Cardiac ultrasound is divided into three main types:

• Static Ultrasound (2D Echo): Displays heart structure and size
• Doppler Ultrasound: Analyzes blood flow velocity and direction

The device emits 2-5MHz sound waves, which are reflected by the chest wall and converted into three-dimensional images by a computer.

Advanced technologies include:

• Myocardial Doppler Imaging: Evaluates myocardial motion velocity
• 3D Ultrasound: Precisely measures ventricular volume

Different types can be combined to obtain comprehensive diagnostic information.

Indications

Common symptoms include:

• Chest pain or shortness of breath
• Follow-up of congenital heart disease

Applicable syndromes include:

• Assessment of ventricular function post-myocardial infarction
• Grading of severity in heart failure
• Monitoring of artificial heart valves

Suitable for evaluating congenital heart defects, cardiomyopathies, pericardial diseases, etc. It is also an important tool for preoperative assessment of cardiac surgical risks and tracking the impact of cancer treatments on the heart.

Usage and Dosage

The examination usually takes 30-60 minutes, during which the patient needs to expose the chest and apply gel. Static examinations can be performed on an outpatient basis, while stress ultrasound requires the patient to cycle or receive dobutamine injection. Transesophageal procedures require local anesthesia and hospitalization.

Control of dosage mainly pertains to sound wave intensity and examination duration. In adults, the sound wave frequency is typically set between 2-5MHz. Special cases, such as children or obese patients, may require adjustments in probe angle and frequency settings.

Benefits and Advantages

The main advantages include:

• Real-time dynamic imaging of cardiac operation
• No radiation exposure, allowing for repeated assessments
• Evaluation of blood flow dynamics and structural abnormalities

It is particularly valuable for diagnosing valvular regurgitation and ventricular systolic dysfunction.

Compared to other examinations:

• Provides more detailed anatomical information than electrocardiograms
• Safer and less costly than cardiac catheterization

It is one of the preferred tools for diagnosing heart diseases.

Risks and Side Effects

Traditional transthoracic ultrasound has almost no side effects; a few patients may experience skin irritation from gel. Transesophageal ultrasound has a 0.5% chance of causing throat discomfort or minor esophageal mucosal abrasions.

Serious risks include: Induction of angina during stress ultrasound or blood pressure fluctuations after drug injection. Very rarely, prolonged examination may cause rib discomfort, but overall risks are below 0.1%.

Precautions and Contraindications

Contraindications include:

• Severe coagulation disorders
• Acute phase of upper gastrointestinal ulcers
• Tracheal stenosis preventing endoscope insertion

Patients should inform the physician of devices such as pacemakers or artificial heart valves before the examination.

Preparation before the examination:

• Fasting for 6 hours before transesophageal ultrasound
• Discontinuing certain cardiac medications before stress testing

Pregnant women should inform the medical staff to adjust probe angles and avoid direct radiation to the fetus.

Interactions with Other Treatments

Interactions with other examinations:

• Complementary information from cardiac catheterization for dynamic and anatomical data
• Interval between nuclear cardiac perfusion scans should be >48 hours

Interactions with medications:

• Beta-blockers may affect ventricular function assessment
• Diuretics may alter cardiac filling status

Medications used during the examination, such as dobutamine, should be coordinated with the patient's routine medications to avoid significant blood pressure fluctuations. There are no direct interactions with radiotherapy, but other invasive procedures may need to be delayed post-examination.

Treatment Efficacy and Evidence

According to the American College of Cardiology guidelines, cardiac ultrasound has a sensitivity of 89-95% for diagnosing heart failure and over 90% specificity for valvular disease assessment. Meta-analyses show a diagnostic accuracy of up to 97% for congenital heart disease.

Clinical studies confirm:

• Stress ultrasound has a positive predictive value of 85% for coronary artery disease
• 3D ultrasound reduces diagnostic errors by 20% compared to traditional 2D scans

It is recommended as a first-line diagnostic tool by the global cardiology societies.

Alternatives

Alternative examinations include:

• Electrocardiogram: Cannot provide anatomical information
• Magnetic Resonance Imaging: Not suitable for patients with implants
• Cardiac catheterization: Invasive and more costly

However, these methods have limitations and cannot fully replace the real-time dynamic assessment provided by ultrasound.

In special cases:

• Obese patients may require high-frequency probes
• Pulmonary interference may necessitate transesophageal approaches

But in most cases, cardiac ultrasound remains the primary diagnostic method.

 

Frequently Asked Questions

Do I need special preparations before a cardiac ultrasound?

Usually, fasting or special preparations are not required. It is recommended to wear clothing that allows easy chest exposure or change into a gown during the exam. For stress tests, avoid eating 2 hours before and bring comfortable athletic shoes. Inform the medical staff if you have skin wounds or are overly sensitive to cold.

Will the procedure cause discomfort?

The procedure is painless and non-invasive, requiring lying flat and remaining still. Gel is applied to the skin for sensor contact; some may find the temperature of the gel or maintaining the position uncomfortable, but generally tolerable. If chest pain or shortness of breath occurs during the exam, notify the technician immediately.

How soon can I receive the results?

Results are typically interpreted by a physician on the same day or the next day. Complex cases may take 1-3 business days. In emergency situations (such as suspected heart failure), the doctor may provide immediate verbal feedback of key findings. The report will detail cardiac structure, blood flow velocities, and clinical significance.

When should a repeat echocardiogram be performed?

If the initial images are unclear (due to obesity or thoracic deformity) or to evaluate treatment effects (such as in heart failure), repeat examinations may be necessary. For suspected endocarditis or artificial valve dysfunction, follow-up scans may be scheduled to monitor changes.

Does an abnormal result always require surgery?

Abnormal findings should be interpreted in conjunction with clinical symptoms and other tests. For example, mild valvular regurgitation without symptoms may only require regular follow-up; severe stenosis or heart failure may need medication or surgery. The physician will develop a personalized treatment plan based on cardiac function indices (such as EF) and blood flow data.