title: Time From the Beginning of the Right Ventricle Isovolumetric Contraction to the Peak of the S Wave: A New TDI Indicator for the Non-Invasive Estimation of Pulmonary Hypertension.
abstract: BACKGROUND
  Echocardiography is a key screening tool in the diagnostic algorithm of pulmonary hypertension (PH). In addition, tissue doppler imaging (TDI) is a promising method for the noninvasive estimation of pulmonary artery pressure (PAP).
  
  
  OBJECTIVE
  The aim of this study was to validate the accuracy of measuring the time from the beginning of the right ventricular isovolumetric contraction time (RV IVRT) to the peak of the S wave in the TDI of the base of the RV free wall (time to peak or TTP), as an indicator for the non-invasive estimation of pulmonary hypertension.
  
  
  METHODS
  In this diagnostic test study, 60 consecutive patients referred for right heart catheterization (RHC) were enrolled. A pulse-wave TDI was performed before the cardiac catheterization, with a mean interval of 1 hour between the two measurements. The TDI variables, such as the RV IVRT, myocardial performance index (MPI), and the new "time to peak" parameter, were measured at the lateral basal RV free wall. The patients were divided into two sub-groups according to the RHC findings: no-PH (mean PAP < 25 mmHg) and PH (mean PAP ≥ 25 mmHg) groups. Then, we calculated the specificity and sensitivity of the TDI parameters (including the TTP) for the diagnosis of PH.
  
  
  RESULTS
  In our study, the TTP showed a significant inverse relationship with the PAP. Based on our results, a TTP of less than 127 ms could be used to predict PH, with a sensitivity and specificity of about 70% (AUC = 0.746 ± 0.064).
  
  
  CONCLUSIONS
  Based on the results of this study, we suggest the use of a novel "time from the beginning of isovolumetric contraction to the peak of the S wave" (TTP) parameter in the TDI of the base of the RV free wall to predict PH with acceptable accuracy in comparison with RHC.
authors: Echocardiography Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, IR Iran.
authors: Mozhgan
authors: M
authors: Parsaee
authors: Department of Cardiovascular Medicine, Echocardiography laboratory, Atherosclerosis Prevention Research Center, School of Medicine, Mashhad University of Medical Sciences, Mashhad, IR Iran.
authors: Fereshteh
authors: F
authors: Ghaderi
authors: Echocardiography Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, IR Iran.
authors: Azin
authors: A
authors: Alizadehasl
authors: Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, IR Iran.
authors: Hooman
authors: H
authors: Bakhshandeh
keywords: Hypertension; Pulmonary; Pulmonary Artery Pressure; Right Heart Catheterization; Tissue Doppler Imaging