What does a TTE (Treadmill Test or Exercise) show?

What Does a TTE (Transthoracic Echocardiogram) Show?

A transthoracic echocardiogram (TTE) is a comprehensive cardiac imaging test that visualizes cardiac structure, function, and hemodynamics, including chamber sizes, wall motion, valve anatomy and function, ejection fraction, diastolic function, and intracardiac pressures. 1

Core Structural Assessment

Cardiac Chamber Evaluation:

• Left ventricular (LV) size, wall thickness, and mass to detect hypertrophy or dilation 1
• Right ventricular (RV) size and function, including assessment for RV dysfunction 1
• Atrial dimensions, particularly left atrial (LA) size and volume, which provide prognostic information in heart failure and valvular disease 1
• Ventricular septal thickness and interventricular septal motion 1

Myocardial Function:

• Left ventricular ejection fraction (LVEF) to differentiate heart failure with reduced ejection fraction (HFrEF, LVEF <40%) from heart failure with preserved ejection fraction (HFpEF, LVEF ≥50%) 1
• Regional wall motion abnormalities that may indicate ischemia or prior infarction 1
• Global longitudinal strain using speckle tracking, which detects subtle systolic dysfunction and provides prognostic information in HFpEF 1
• Diastolic function parameters, including mitral inflow patterns (E/A ratio), tissue Doppler velocities (e'), and E/e' ratio to estimate LV filling pressures 1

Valvular Assessment

Comprehensive Valve Evaluation:

• Valve anatomy and morphology, including leaflet thickness, calcification, and structural abnormalities 1
• Mitral valve area in mitral stenosis using pressure half-time method, with severe stenosis defined as valve area <1.5 cm² 1
• Aortic valve area and gradients in aortic stenosis, with severe stenosis defined as valve area <1.0 cm² or mean gradient >40 mmHg 1
• Regurgitation severity for all four valves using color Doppler, vena contracta width, and regurgitant volume 1
• Mitral valve apparatus, including papillary muscle position and chordal structure, particularly important in hypertrophic cardiomyopathy (HCM) 1

Hemodynamic Parameters

Pressure Measurements:

• Left ventricular outflow tract (LVOT) gradients at rest and with provocation (Valsalva), critical for diagnosing obstructive HCM (gradient ≥50 mmHg indicates obstruction) 1
• Pulmonary artery systolic pressure estimated from tricuspid regurgitation velocity, with exercise-induced elevation >60-70 mmHg suggesting significant pulmonary hypertension 1
• Mean mitral gradient in mitral stenosis, with severe stenosis showing mean gradient >10 mmHg 1
• Transmitral flow velocities to assess diastolic function and estimate LA pressure 1

Specialized Applications

Hypertrophic Cardiomyopathy:

• Distribution and magnitude of LV hypertrophy, particularly asymmetric septal hypertrophy (wall thickness ≥15 mm) 1
• Systolic anterior motion (SAM) of the mitral valve causing dynamic LVOT obstruction 1
• Mitral regurgitation secondary to SAM 1

Heart Failure Evaluation:

• LA reservoir strain, which is a powerful prognostic factor in HFpEF and superior to conventional parameters 1
• LA longitudinal systolic and diastolic function, which correlates with reduced functional capacity in HFpEF 1
• RV function assessment, as RV dysfunction predicts worse outcomes 1

Exercise/Stress Echocardiography Capabilities

When combined with exercise (stress TTE), additional information includes:

• Exercise-induced LVOT obstruction in HCM patients without resting gradients, using treadmill or bicycle protocols 1
• Exercise-induced changes in mitral gradient and pulmonary artery pressure when resting findings don't match symptoms in mitral stenosis 1
• Functional capacity assessment through exercise duration and hemodynamic response 1
• Provocation of valvular gradients when there is discrepancy between resting echocardiographic severity and clinical symptoms 1

Common Pitfalls to Avoid

Technical Limitations:

• Poor acoustic windows in obese patients or those with lung disease may require contrast enhancement or alternative imaging (CMR) 1
• Underestimation of LVOT gradients in HCM if only resting measurements are obtained—provocative maneuvers or exercise testing may be needed 1
• Overreliance on single parameters for valve assessment—comprehensive evaluation requires multiple measurements 1

Clinical Interpretation Errors:

• E/e' ratio has limited accuracy in tracking filling pressures in individual HFpEF patients and should not be used to titrate therapy 1
• Normal LVEF does not exclude HFpEF—diastolic dysfunction parameters and strain imaging are essential 1
• Exercise-induced pulmonary hypertension (RV systolic pressure >60-70 mmHg) should prompt careful symptom assessment even without formal guideline thresholds 1

When TTE is Insufficient

Indications for Advanced Imaging:

• Inconclusive TTE findings warrant CMR for definitive diagnosis of HCM or assessment of hypertrophy distribution 1
• Discrepancy between symptoms and resting TTE requires exercise echocardiography or invasive hemodynamic assessment 1
• Apical HCM or apical infarction may require contrast echocardiography or CMR when standard TTE is inadequate 1