Timing and magnitude of regional right ventricular function: a speckle tracking-derived strain study of normal subjects and patients with right ventricular dysfunction.

摘要

BACKGROUND: The aim of this study was to evaluate the timing and magnitude of global and regional right ventricular (RV) function by means of speckle tracking-derived strain in normal subjects and patients with RV dysfunction. METHODS: Peak longitudinal systolic strain (PLSS) and time to PLSS in 6 RV segments (the basal, mid, and apical segments of the RV free wall and septum) were obtained in 100 healthy volunteers and 76 patients with RV dysfunction by tracking speckles inside the myocardium using grayscale images. Global PLSS and time to PLSS were based on the average of the 6 regional values. RESULTS: There was a significant and close correlation between RV contractility as measured by PLSS and tricuspid annular plane systolic excursion (r = -0.83, P < .001). In normal subjects, PLSS was significantly greater in the free wall than in the septum (-28.7 + or - 4.1% vs -19.8 + or - 3.4%, P < .001), whereas time to PLSS was similar in the different regions of the right ventricle. In patients with RV dysfunction, global and regional PLSS was significantly less than in normal subjects (-13.7 + or - 3.6% vs -24.2 + or - 2.9%, P < .001), and a global PLSS cutoff value of -19% was helpful in distinguishing the two groups. Furthermore, time to PLSS in all of the RV septal segments and dispersion in RV contraction timing were significantly longer. Global PLSS in the patients with RV dysfunction was also significantly less in the presence of moderate to severe pulmonary hypertension (-12.7 + or - 3.6% vs -14.4 + or - 3.4%, P = .038). CONCLUSIONS: Speckle tracking not only makes it possible to quantify global RV function but also illustrates the physiology of RV contraction and the pattern of activation at regional level. Speckle tracking-derived strain could become an important new means of assessing and following up patients with impaired RV function and increased pulmonary pressure.