A 58-year-old man from Delhi presents to the emergency department with acute onset chest pain radiating to the left arm for 2 hours. On examination, his blood pressure is 145/92 mmHg, heart rate 102/min, and JVP is elevated at 8 cm H₂O. Auscultation reveals an early diastolic decrescendo murmur at the left sternal border. Chest X-ray shows pulmonary edema. Echocardiography demonstrates a dilated left ventricle with an ejection fraction of 35%. Which of the following best explains the elevated JVP in this patient?