What do echocardiogram measurements assess?

Echocardiogram Measurements and Their Clinical Assessment

Echocardiogram measurements comprehensively assess cardiac structure, function, and hemodynamics, providing crucial information for diagnosing cardiovascular conditions, guiding treatment decisions, and monitoring disease progression to reduce morbidity and mortality.

Chamber Quantification and Structure Assessment

Left Ventricle (LV) Measurements

• Dimensions and Volumes:
  • LV diameters (end-diastolic and end-systolic)
  • LV volumes (end-diastolic and end-systolic volumes)
  • LV mass calculation and indexing to body surface area (BSA)
  • Sphericity index (LV short-to-long-axis dimension ratio at end-diastole) with cut-off value of 0.76 1

Systolic Function Assessment

• Global Function Parameters:
  • Left ventricular ejection fraction (LVEF) - percentage of blood ejected per contraction
  • Fractional shortening (M-mode measurement)
  • Stroke volume and cardiac output calculations
  • Global longitudinal strain (GLS) - detects subclinical dysfunction before LVEF reduction 1

Regional Function Assessment

• Wall Motion Analysis:
  • Regional wall thickening and endocardial excursion
  • Segmental wall motion abnormalities (critical for ischemic disease detection) 1
  • Distribution patterns of regional strain (valuable for specific cardiomyopathies, e.g., apical sparing in cardiac amyloidosis) 1

Diastolic Function Assessment

• Key Parameters:
  • E/A ratio (ratio of early to late diastolic filling velocities)
  • E/e' ratio (ratio of early mitral inflow velocity to early diastolic mitral annular velocity)
  • Deceleration time of early filling
  • Isovolumic relaxation time
  • Left atrial volume index

Right Heart Assessment

Right Ventricle (RV) Measurements

• Dimensions:
  • RV basal diameter (normal range: 25-41 mm)
  • RV mid diameter (normal range: 19-35 mm)
  • RV longitudinal diameter (normal range: 59-83 mm) 1
  • RV wall thickness (normal range: 1-5 mm)

RV Function Parameters

• Systolic Function:
  • Tricuspid annular plane systolic excursion (TAPSE)
  • RV fractional area change (FAC)
  • RV ejection fraction (via 3D echocardiography)
  • S' velocity by tissue Doppler imaging

Valvular Assessment

Valve Structure and Function

• Morphological assessment of valve leaflets/cusps
• Valve orifice area measurements
• Regurgitation quantification (vena contracta, PISA method)
• Stenosis severity assessment (pressure gradients, valve area)

Hemodynamic Assessment

• Pressure Measurements:
  • Estimated pulmonary artery systolic pressure (sPAP)
  • Estimated right atrial pressure
  • Transvalvular gradients
  • E/e' ratio for left ventricular filling pressures 1

Clinical Applications and Disease-Specific Assessments

Cardiomyopathies

• Dilated Cardiomyopathy:

  • Ventricular dilation with normal wall thickness and reduced systolic function 1
  • Assessment for intracardiac thrombi

• Hypertrophic Cardiomyopathy:

  • Wall thickness measurements (septal morphology and hypertrophy localization)
  • Assessment of dynamic outflow tract obstruction
  • 3D assessment of LVOT recommended in obstructive cases when septal reduction therapy is indicated 1

• Restrictive Cardiomyopathy:

  • Normal ventricular size and systolic function with atrial enlargement
  • Characteristic inflow velocity profiles with shortened deceleration time 1

Valvular Heart Disease

• Comprehensive Assessment:
  • LV remodeling in chronic valve diseases
  • LV total and effective stroke volume
  • Regurgitant volumes calculation
  • Tricuspid annular diameter in mid-systole (cut-off for annuloplasty = 40 mm) 1

Pericardial Disease

• Key Findings:
  • Pericardial effusion detection and quantification
  • Signs of tamponade (right atrial collapse, diastolic RV collapse)
  • Constrictive pericarditis features (pericardial thickening, respiratory variation in flow velocities) 1

Advanced Techniques

Three-Dimensional Echocardiography

• Provides accurate assessment of:
  • LV and RV volumes and ejection fraction
  • LV mass in abnormally shaped ventricles
  • LVOT area in aortic stenosis (avoiding underestimation from geometric assumptions) 1
  • Valve anatomy and function

Strain Imaging

• Detects subclinical myocardial dysfunction
• Helps differentiate various cardiomyopathies
• Predicts postoperative recovery of LV function in valvular disease 1

Clinical Pitfalls and Considerations

• Technical Limitations:

  • M-mode measurements are prone to errors in patients with inadequate acoustic access, abnormally shaped ventricles, or segmental wall motion abnormalities 1
  • RV quantification is challenging due to complex shape and heavy trabeculation 1

• Interpretation Challenges:

  • Diastolic function indices are load-dependent and require careful interpretation 1
  • Right heart measurements require multiple acoustic windows for accurate assessment 1

• Indexing Importance:

  • Linear and volumetric measurements should be indexed to BSA to avoid misdiagnosis 1
  • In overweight/obese patients, indexing LV mass to height powered to 2.7 or 1.7 may better identify LV hypertrophy 1

Echocardiography remains the cornerstone of non-invasive cardiac assessment, providing critical information for diagnosis, risk stratification, treatment decisions, and monitoring of cardiovascular diseases, ultimately improving patient outcomes through early detection and appropriate management.