Introduction to Echocardiography

Introduction to Echocardiography

• Echocardiography is a non-invasive diagnostic technique used to visualize the heart and its structures.
• It employs ultrasound waves to create images of the heart's internal anatomy and function.
• Images can reveal the size, shape, and motion of the heart's chambers, valves, and great vessels.
• Different modalities exist, including transthoracic echocardiography (TTE), transesophageal echocardiography (TEE), and stress echocardiography.

Transthoracic Echocardiography (TTE)

• Performed with a transducer placed on the chest wall.
• Provides images of the heart from outside the body.
• Commonly used for initial cardiac evaluations.
• Relatively low cost and readily available.
• Limited by bone and lung interference, reducing resolution for certain deep cardiac structures.

Transesophageal Echocardiography (TEE)

• Performed with a transducer placed through the esophagus.
• Provides higher-resolution images of the heart than TTE.
• More useful for assessing anatomical detail, particularly of the heart valves and posterior structures.
• Requires patient sedation.
• Can be used to guide certain interventional procedures.
• Commonly used for detailed evaluation of valvular function and suspected structural abnormalities.

Stress Echocardiography

• Echocardiography performed during or immediately after exercise or pharmacological stress.
• Evaluates heart function during increased workload.
• Helps identify coronary artery disease by detecting myocardial ischemia.
• Shows the response of the heart to stress and its pumping ability.
• Used in patients with suspected angina or other coronary artery disease, and to assess the risks of cardiac surgery or other procedures.
• Provides a method to measure the heart's output under conditions of stress.

Echocardiographic Examinations

• Different views of the heart are generated for a complete assessment.
• M-mode: Displays motion of the cardiac structures over time.
• Two-dimensional (2D) echocardiography: Creates images of the heart in a cross-sectional manner.
• Doppler echocardiography: Measures the velocity and direction of blood flow within the heart, revealing pressure gradients across valves.
• Color Doppler: Visualizes blood flow patterns by assigning colours to different velocities (e.g. turbulent flow around diseased valves).

Echocardiographic Findings/Indications

• A variety of clinical scenarios necessitate echocardiographic evaluation, including:
  • Valvular heart disease (mitral stenosis, aortic regurgitation, etc.)
  • Cardiomyopathies (hypertrophic cardiomyopathy, dilated cardiomyopathy, etc.)
  • Congenital heart defects
  • Pericardial disorders
  • Aortic dissection
  • Cardiac tumors
  • Assessment of ventricular function (ejection fraction, left ventricular systolic function, etc.)
    • Evaluation for cardiac causes of shortness of breath or chest pain
  • Monitoring patients with heart disease already diagnosed

Applications and Significance

• Crucial tool in diagnosing and assessing various cardiac conditions.
• Forms the basis for treatment planning in many patients with heart conditions.
• Useful for monitoring the effectiveness of therapeutic interventions.
• Helps estimate the risk for future cardiac events.
• Valuable in guiding invasive procedures.

Limitations of Echocardiography

• Sensitivity and resolution can vary, depending on the type of echocardiogram being performed.
• Not suitable in all cases or for all diagnoses.
• Patient factors, such as body habitus or presence of obesity or lung conditions, can affect image quality.
• Operators skill level can influence image quality and accurate interpretations.
• Findings should be integrated with other diagnostic tools for a complete clinical picture.