Possible side effects of cardiac imaging include puncture site bleeding or subcutaneous hematoma, contrast allergy, renal impairment, vascular injury, and cardiac arrhythmia. 1. Puncture site bleeding or subcutaneous hematoma: improper hemostasis at the puncture site after imaging may cause bleeding or subcutaneous hematoma at the puncture site. 2. Allergy to contrast medium: the general contrast medium is iodine-containing contrast medium, and a few patients may have allergy to contrast medium with gastrointestinal symptoms, skin rash, etc., and a very small number of patients may suffer from anaphylactic shock. 3. Kidney function damage: after the end of contrast, the contrast agent will be excreted with urine, which may cause certain damage to the kidneys, so patients with poor renal function should be comprehensively assessed to see if they can tolerate the contrast agent, in order to prevent acute kidney injury. 4. Vascular injury: The guidewire and catheter used during contrast may puncture blood vessels. 5. Arrhythmia: If the guidewire and catheter accidentally enter the atrium during imaging, there is a risk of inducing arrhythmia. If there is any discomfort, it is recommended to consult a doctor in time and standardize the treatment under the doctor’s guidance.