Abstract 2100: Left Ventricular Mechanics in Pulmonary Hypertension: A Velocity Vector Analysis of Greyscale Cardiac Images
Background: Right ventricular (RV) function influences left ventricular (LV) function in cardiac and cardiopulmonary diseases. We assessed the effect of RV function on LV peak systolic twist and rate of LV untwisting in patients with pulmonary arterial hypertension (pHTN).
Methods: We studied 35 patients with pHTN and 10 patients with normal RV and LV function. Clinical classifications included functional subgroups of pHTN: classes 1 (n=10), 2 (n=10), 3 (n=8), and 4 (n=7). Images were obtained with a Siemens Sequoia system in both basal and apical LV short axis views. RV pressures, pH, pO2 and pCO2 were obtained to confirm diagnosis and classification. Vector Velocity Imaging (VVI, Siemens) was used for offline analysis of LV twist and untwisting.
Results: At baseline, peak LV systolic twist was 10.4° ± 5° in all 10 healthy subjects, while in all pHTN patients a significant decrease in LV twist to 5.3° ± 4.6° as well as in untwisting to −1.9° ± 2.4° was found. Notably, twist and untwisting in the control group was highest in the septal and inferior area, while in all patients with pHTN twist and untwisting was most significantly decreased in the septal area. Marked dyssynchrony in septal and inferior wall twist and untwisting was seen in all pHTN patients. An inverse relationship between RV pressure and peak LV systolic twist and diastolic untwisting was found. Patients with high RV pressures showed the largest decrease in peak twist and untwisting as well as delay and loss of synchrony in untwisting of the LV.
Conclusion: In our study of pHTN patients, peak LV twist and untwisting decreased with increasing RV pressure load, and time to peak LV untwisting increased as compared to normal patients.