A 40-year-old male farmer presents with 3 days of irregular fever accompanied by headache, low back pain, and blurred vision to a rural clinic. Physical exam shows facial and upper chest congestion, conjunctival edema, petechiae, and scattered pinpoint hemorrhages in the axilla and back. BP is 90/60 mmHg. As similar cases were reported in his village, he was transferred to a city hospital with suspected epidemic hemorrhagic fever (febrile phase). On the first night, he suddenly developed dyspnea and orthopnea. Examination reveals heart rate 140 bpm, gallop rhythm, and bilateral rales/crackles, suggesting acute left-sided heart failure (HF). The most likely mechanism is: