Testing & Diagnostics

Cardiac Auscultation

Listening to the heart with a stethoscope to detect murmurs, arrhythmias, and abnormal heart sounds. Annual cardiac auscultation is the standard first-line screening for heart disease in all dogs.

Cardiac auscultation — listening to the heart with a stethoscope — is the simplest, most accessible tool for detecting heart disease in dogs. It should be performed at every annual wellness examination and at any appointment where cardiac disease is a concern.

What Auscultation Can Detect

  • Heart murmurs: turbulent blood flow creating an audible “whooshing” sound between normal heart sounds
  • Arrhythmias: irregular rhythms (bradycardia, tachycardia, premature beats)
  • Abnormal heart sounds: split S2, gallop rhythms — indicators of elevated filling pressures or severe myocardial dysfunction
  • Muffled sounds: suggestive of pericardial effusion

Murmur Grading (I–VI)

GradeDescription
I/VIVery soft; detectable only with careful auscultation in quiet room
II/VISoft; easily heard; no cardiac thrill
III/VIModerate intensity; no thrill
IV/VILoud; no thrill
V/VIVery loud; palpable thrill (vibration felt on chest wall)
VI/VIHeard with stethoscope held off chest; palpable thrill

Higher grades generally correlate with more significant disease, but grade alone does not determine clinical significance — echocardiography is required to assess severity.

Limitations

Auscultation cannot:

  • Determine the cause of a murmur (valvular vs. congenital vs. functional)
  • Quantify disease severity
  • Detect occult DCM (Dobermans often have no murmur until late disease)
  • Identify subtle arrhythmias (24-hour Holter monitoring is needed)

For breeds with cardiac disease risk (Cavalier, Doberman, Boxer, Irish Wolfhound, Great Dane), auscultation identifies the murmur, but echocardiography is required to determine disease stage, severity, and timing of treatment initiation.