Arterial Pressure Respiratory Variation. Model-generated distal arterial pressure for the right (pulmonary arterial pressure (PPA)) and left (aortic pressure (PAO)) heart. In the control case for the left heart with respiratory excursion of -1 to -10 mmHg, 7.3% variation exists (Panel G). With the same breathing pattern, aortic pressure drops and an 11.8% pressure variation exists (Panel H), indicating pulsus paradoxus. For the right heart, pressure elevates and variation decreases with effusion (compare Panels D-E). With a deeper breathing pattern (-1 to -15 mmHg), variation increases in both cases (Panels F and I).