Q. A 53-year-old woman comes to the emergency department because of severe right lower limb pain that started 2 hours ago. The patient’s medical history is significant for breast cancer, and she is currently on chemotherapy. Her vital signs are normal except for tachycardia. Upon examination, her right lower limb appears red and swollen. The dorsalis pedis pulses are palpable, bilaterally. A provisional diagnosis of deep venous thrombosis is made, and the patient is scheduled for an urgent venous duplex. On her way to the sonography room, she suddenly reports weakness in her left arm and leg. Which of the following is most likely present on cardiac auscultation?