Testing & Diagnostics

Echocardiogram

Ultrasound imaging of the heart that shows real-time cardiac structure and function. Used to diagnose and monitor heart disease in dogs, including mitral valve disease and dilated cardiomyopathy.

An echocardiogram (echo) is an ultrasound examination of the heart that produces real-time images of cardiac structures and blood flow. It is the most informative single test for diagnosing and monitoring heart disease in dogs.

What Echocardiography Measures

A standard echocardiogram provides:

Structural assessment:

  • Chamber dimensions (left and right ventricle, left atrium)
  • Wall thickness and motion
  • Valve morphology (mitral, aortic, tricuspid, pulmonic)
  • Presence of pericardial effusion or cardiac masses

Functional assessment:

  • Ejection fraction (EF): percentage of blood ejected per contraction; normal dogs >50%
  • Fractional shortening (FS): simpler measure of systolic function; normal 25–45%
  • Left atrial to aortic ratio (LA:Ao): key measure of left atrial enlargement; >1.6 in context of MVD suggests significant disease

Doppler assessment:

  • Blood flow velocity across valves
  • Regurgitation quantification (backward flow through diseased valves)
  • Pulmonary artery pressure estimation

Clinical Applications by Disease

Mitral valve disease (MVD): Echo identifies valve thickening (myxomatous degeneration), regurgitant jet severity, and left atrial and ventricular enlargement. The ACVIM Cavalier guidelines use echo-defined LA:Ao >1.6 and vertebral heart score thresholds to trigger medication (pimobendan) initiation.

Dilated cardiomyopathy (DCM): Echo shows dilated, poorly contractile chambers — hallmark of DCM. Critical for Dobermans in the occult phase (no symptoms, but echo shows disease).

Pericardial effusion: Echo immediately confirms fluid around the heart and guides pericardiocentesis.

Frequency Recommendations by Breed

  • Cavalier King Charles Spaniel: annual from age 1–2 (MVD monitoring)
  • Doberman Pinscher: annual from age 3–4 (occult DCM screening)
  • Boxer: annual from age 3 (arrhythmogenic right ventricular cardiomyopathy monitoring)
  • Golden Retriever, Irish Wolfhound, Great Dane: breed-appropriate cardiac screening from age 3–4

Echo vs. Radiographs vs. Auscultation

Auscultation detects murmurs but cannot characterize severity or chamber changes. Radiographs show heart size and pulmonary edema but not internal structure or valve function. Echocardiography provides the definitive assessment of all three — structure, function, and hemodynamics — and is the standard of care for cardiac monitoring in dogs with known or suspected heart disease.