Case Studies

These case studies contain detailed information on the diagnostic and treatment process for each individual animal.

Chloe

Chloe

Case Background

Name: Chloe
Age: 14 months
Sex: Female, intact
Breed: Golden retriever

Clinical History

Please review Chloe’s clinical history.

Chloe had an abnormal heart rhythm heard on exam.  She also has a loud left basilar systolic murmur and weak femoral pulse quality.    

ECG

View Chloe’s electrocardiogram (the black bar represents one second)
What abnormalities are present on this ECG?
Relevant Findings: The heart rate averages 130 bpm, which is a normal rate for a dog. Every P wave is followed by a QRS; however, there is a single QRS in the middle of the recording (circled) that is wide, abnormal in morphology, and does not have a P wave preceding it. This is consistent with a premature ventricular complex, or PVC. The predominately negative QRS polarity of this PVC in lead II suggests a left ventricular origin. The amplitude of the R wave (double headed arrow) in lead II is 36 mm, which at this calibration (10 mm/mV) equates to an R wave amplitude of 3.6 mV. This is higher than normal for a dog, and is a finding consistent with left ventricular hypertrophy or enlargement. Finally, the ST segment (downward facing arrow) is depressed 2 to 3 mm from the resting baseline, which is compatible with subendocardial ischemia of the left ventricle. View an annotated image of Chloe’s ECG highlighting the relevant findings.

 

Diagnosis & Treatment

 
Discussion:  These changes suggest a disease process affecting the left ventricle. In a young golden retriever with a left basilar heart murmur and weak pulse quality, subaortic stenosis would be the top differential diagnosis, which would require echocardiographic evaluation for confirmation and to assess disease severity. Treatment/management: A single PVC may not require treatment; if signs of syncope are noted or longer ECG recordings (e.g., a 24-hour Holter monitor) show more malignant runs of ventricular ectopy, then antiarrhythmic therapy would be considered. If subaortic stenosis is confirmed on echocardiography with a moderate or severe gradient, atenolol therapy may be considered for cardioprotection and potential antiarrhythmic effects.

    The CEG is funded through an educational grant from Boehringer Ingelheim Vetmedica, Inc., IDEXX Laboratories, Inc. and Nestle Purina PetCare.

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