A 58-year-old man with a 10-year history of hypertension presents to the emergency department with acute dyspnea, orthopnea, and bilateral ankle edema. His blood pressure is 165/105 mmHg, heart rate 112 bpm, and JVP is elevated at 8 cm H₂O. Echocardiography reveals a left ventricular ejection fraction (LVEF) of 35% with global hypokinesis. Cardiac catheterization shows elevated pulmonary capillary wedge pressure (PCWP) of 28 mmHg. Which of the following mechanisms BEST explains the reduced cardiac output in this patient?