An approximately 7-yr-old male dusky pygmy rattlesnake (Sistrurus miliarius barbouri) developed marked depression in mentation shortly after restraint in an acrylic tube during a preventative health evaluation. Radiographs taken during the examination demonstrated a constrictive lesion due to the restraint tube at the level of the heart. A presumptive diagnosis of iatrogenic pseudo-pericardial tamponade was made, and the animal was immediately removed from the restraint tube. The snake's mentation returned to normal within a few minutes. Plasma collected during the examination was tested for cardiac troponin I (cTnI), which measured 0.06 ng/ml. Re-evaluation of the snake 6 wk later revealed the snake had continued to eat and behave normally. During the reassessment, the snake's plasma cTnI was found to have decreased to 0.00 ng/ml. The snake has continued to do well for the last year, before writing this case report. This is the first description of pseudo-pericardial tamponade in a venomous snake due to restraint in a tube. This is also the first description of elevated plasma cTnI associated with a cardiogenic disorder in a reptile.