Structural Heart Disease

    .

    Physical Exam

    • Generally physical exam is used to determine whether echo is needed to evaluate the finding.
    • Mild Grade 1-2/6 midsystolic crescendo-decrescendo murmurs are usually bening, do not warrant testing.
      • Turbulent flow across pulmonic or aortic valve
      • Echo is not indicated
    • i.e. Asymptomatic more intense holosystolic or diastolic murmur
      • Echo is indicated to evaluate more significant valve disease.

     

    Diagnostic Testing

    • Generally first test with suspected pathologic disease.
    • Provides lots of info: valve morphology, function, pericardial disease, PA pressures, visualized proximal great vessels (PA, Aorta).
    Diagnostic Test Major Indications Advantages Limitations
    Transthoracic Echo

    - Heart Failure

    - Cardiomyopathy

    - Valve Disease

    - Congenital Heart Disease

    - Pulmonary hypertension

    - Aortic Disease

    - Pericardial Disease

    - Presence and severity of SHD

    - Quantitation of LV size/function

      PA pressures, valves, shunts.

     

    - No known adverse effects

    - Widely available, portable

    - Image Quality limits diagnosis in 

      some patients, may require microbubble

      contrast agents.

    Transesophageal Echo

    - Endocarditis

    - Prosthetic Valve Dysfunction

    - Aortic Disease

    - Left atrial thrombus

    - High quality images (posterior shunts)

    - Most accurate for endocarditis,

      prosthetic valves, LA thrombus.

    - Requires esophageal intubation, 

      typically w/ conscious sedation

    3D Echo

    - Mitral valve disease

    - Interatrial septum (ASD)

    - Better tomographic imaging.

    - Used for device placement and other

      cardiac procedures.

    - Better assessment of LV global/

      regional systolic function

    - Adjunct, limited availability.

    Radionucleotide

    angiography

    - LV systolic function

    - Quantitative LV EF measurements.

    - Radiation exposure

    - No data on other cardiac structures.

    Cardiac Catheterization

    - Congenital Heart Disease

    - Coronary angiography

    - Direct measurement of intracardiac

      pressures

    - Contrast allows good anatomy view

    - Percutaneous interventions.

    - Invasive

    - Radiation and radiocontrast exposure

    - Images not tomographic, limits 3D

      visualization.

    CMR Imaging

    - CHD

    - Aortic Disease

    - Myocardial viability

    - Myocardial disease 

      (infiltrative, myocarditis,

       HCM)

    - RV cardiomyopathy (ARVC)

    - Quantitation of LV mass/

      function.

    - High-res tomographic imaging + flow 

      data.

    - Quantitative RV volumes, LVEF.

    - No radiation

    - 3D reconstruction of aortic and

      coronary anatomy.

    - Limited availability

     

    - May be contraindicated in: Pacemakers

      ICD, other implantable devices.

     

    - Gadolinium contraindicated in renal

      failure

    - Sinus rhythm and slower HR needed

      for good image quality

    Chest CT

    - Aortic Disease

    - Coronary Disease

    - Cardiac Masses

    - Pericardial Disease

    - High res tomographic images

    - 3D reconstruction of coronaries

    - Radiation + dye exposure

    - Better images with sinus rhythm and

      slower rate.

     

     

    Key Points

    • Transthoracic echo (TTE) is typically the first line test for SHD.
      • Sometimes TEE is first line if:
        • Endocarditis (sometimes) better special resolution (for small mobile vegetation in setting of bacteremia).
        • Prosthetic valves (poor visualization with TTE)
        • Ascending/Descending aortic disease (out of window for TTE)
        • LA thrombus (posterior structure, too far from TTE... i.e. as in pre-cardioversion for AF).
      • Echo Transpulmonary contrast:
        • Agitated saline - evaluate shunts.
          • Injected into peripheral IV, goes to R-side, and cleared by pulmonary circuit.
          • L-side should NOT have bubbles, if it does, it suggests:
            • Intracardiac shunt (i.e. ASD)
            • Pulmonary (i.e. AV malformation)
        • Microbubble
          • Croses pulmonary vessels, allows evaluation of LV endocardial borders.
          • Esp helpful if pts are large or have lung disease that LV is normally hard to visualize wall motion.
    • MUGA (radionucleotide angiography)
      • LV Function (better than echo).
    • Cardiac Cath
      • Severity of valve lesions (pressure gradients)
    • Cardiac MRI
      • Congenital heart disease.
        • Previous surgical anasthomosis in CHD is hard to see with echo.
        • CT angiography can also be used to define this anatomy.

     

    • Others:
      • Hand-held echo: Assist in acute triage, but operator dependent.  Should not be used for full studies.

     

    Trans-esopageal Echo (TEE)

    • Pt must be sedated.
    • Transducer passed into esophagus to area directly behind the LA.  
    • Can cause oropharynx or trauma to esophagus.
    • Gives excellent resolution of posterior structures: LA, and LA appendage, and mitral valve.

     

    3D Echo

    • Multiplanar reconstruction of 2D cuts.
    • Mostly used for mitral valve anatomy - defines location and cause of mitral regurg.
    • Mostly done with trans-esophageal.

     

    MRI

    • Excellent endocardial wall definition.
    • Uptake of gadolinium defines scars/fibrosis.

     

    PA Cath

    • Provides information on:
      • cardiac output
      • wedge pressure (L-sided filling pressures)
      • SVR
      • mixed venous O2 sat
      • cardiac shunts.
      • Pulmonary HTN
    • Often used in decompensated heart failure, cardiac transplant.  
    • In the past aggressively used in ICU setting, but multiple studies indicating using this to guide treatment doesn't alter outcome.
      • PA catheters no longer indicated in hemodynamically stable patients.
    • Still used in:
      • Pulmonary HTN (if considering vasodilator therapy)
      • Decompensated HF (improve hemodynamics)

    Aortic StenosisEdit section

      • Replacement is indicated for patients with severe aortic stenosis: valve gradient > 40 mmHg and
        • Symptoms such as dyspnea, chest discomfort, syncope.
        • LVEF is abnormal < 50%
        • Poor response to exercise (hypotension, symptoms).
        • Rapid AS progression (i.e. mean gradient > 60 mmHg).
        • Other cardiac surgery is planned.
      • If patient is asymptomatic: repeat physical exam in 6 months, repeat echo in 12 months. 
    • Surgical valve repair/replacement is the only definitive treatment.
    • Workup:
      • If systolic dysfunction and moderate AS --> do dobutamin stress echo to find the true severity of AS. (low flow, low gradient AS)
      • Also assesses underlying CAD.
    • Treatment options:
      • Balloon aortic valve replacement
        • Indicated for severe AS with hemodynamic compromise. (bridges to aortic valve repair).
        • Only mild improvement, and high rate of restenosis.
        • High complications (stroke, MI, death)
      • Transcatheter aortic valve replacement (TAVI)
        • Reserved for very high predicted operative mortality.
        • Superior to medical therapy.
        • Mortality equivalent to surgical replacement.
      • Surgical valve repair
        • Recommended therapy.

     

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