What causes shortness of breath with left ventricular failure?

Shortness of breath in left ventricular failure occurs primarily due to pulmonary congestion. When the left ventricle fails to pump blood effectively, blood backs up into the pulmonary circulation, increasing pressure in the lungs. This leads to fluid leakage into the lung tissues and alveoli, causing pulmonary edema and resulting in difficulty breathing. Additionally, reduced cardiac output can impair oxygen delivery to tissues, further contributing to the sensation of breathlessness.