Pulmonary venous hypertension is pulmonary hypertension resulting from elevated left sided filling pressures. This may result from chronic elevation of left atrial pressures from heart failure; either heart failure with reduced ejection fraction (HFrEF) or heart failure with preserved ejection fraction (HFpEF) or from valvular heart disease. This is classified as Group 2 pulmonary hypertension in the Dana point classification. Pulmonary hypertension due to left heart disease is defined as mean pulmonary arterial pressure (mPAP) greater than or equal to 25 mm Hg, pulmonary capillary wedge pressure (PCWP) of greater than or equal to 15 mm Hg and pulmonary vascular resistance (PVR) greater than 3WU. Chronic elevation of left ventricular end diastolic pressures will result in increased left atrial pressures, initially causing passive congestion and rise in pulmonary venous pressures and resulting pulmonary arterial hypertension. This usually reverses readily with diuresis and lowering the left atrial pressures.