Name: Max
Age: 10 years old
Sex: Male, neutered
Breed: German Shepherd

Please review Max’s clinical history.

Max is presented to your clinic today for evaluation of acute collapse on this morning’s walk. The owner notes that he has been progressively lethargic over the last few weeks. Max is quiet, alert and responsive on exam and reluctant to stand. His heart sounds are difficult to auscultate. His pulses are weak in quality and vary with his respiration. His gums are pale with a prolonged capillary refill time.  

View Max’s electrocardiogram (the black bar represents one second)

 

 
Discussion: 
Electrical alternans in pericardial effusion is caused by the swinging of the heart within the pericardial sac towards and away from the recording electrodes. Electrical alternans is reported in approximately a third of dogs with pericardial effusion, usually more common in dogs with large volume effusion. Treatment/management:
This dog has clinical findings of cardiac tamponade (episode of collapse, weakness, weak pulses, pale gums with prolonged CRT). The variable pulses with respirations are indicative of pulses paradoxus – another finding suggestive of cardiac tamponade. Cardiac imaging (either point-of-care ultrasound or echocardiogram) is recommended to confirm suspected pericardial effusion and cardiac tamponade. Urgent treatment with pericardiocentesis is the recommended to relieve the cardiac tamponade.