Investigation of Dysynchrony in Patients With Pulmonary Hypertension

The second part of the study will include patients with pulmonary hypertension \>5 who are scheduled for a cardiac catheterization for clinical reasons. We will at the conclusion of the routine catheterization, place two pacing catheters within the right atrium and right ventricle and pace the heart at a rate approximately 10% higher than sinus rhythm for 5 minutes. We will then measure dP/dT max in the ventricles, blood pressure and cardiac output using a Fick equation to assess hemodynamics. We will repeat this 3 times using different sites in the right ventricle while simultaneously obtaining echoes to assess mechanical synchrony.