Final answer:
Based on the health record, the true statement D.) regarding Mrs. Short's condition is that she has shortness of breath and an irregular heartbeat, most likely due to the operation.
Step-by-step explanation:
The excerpt from the patient's health record helps us determine which statement is true about Mrs. Short's condition. The statement in the record that her chest x-ray is normal suggests that there is no postoperative pericardial effusion, as this would likely show up on the radiograph. Since Mrs. Short is mentioned as afebrile (without fever), the doctor does not believe she has endocarditis, which is an inflammation of the heart's inner lining. The record indicates that Mrs. Short's shortness of breath and tachycardic episodes are 'most likely postoperative atrial flutter.' Therefore, the true statement given the health record information is D. Mrs. Short has shortness of breath and an irregular heartbeat, most likely due to the operation.