title: Heart rate-corrected QT interval and QT dispersion in patients with pulmonary hypertension.
abstract: OBJECTIVE
  Heart rate-corrected QT interval (QTc) and QTc dispersion (QTcd) are increased and associated with ventricular arrhythmia and an increase in sudden death in a variety of diseases. This study aimed to examine QTc and QTcd in pulmonary hypertension and assess their relationship with pulmonary arterial pressure.
  
  
  METHODS
  A total of 201 patients who had undergone right heart catheterization for a preliminary diagnosis of pulmonary hypertension between December 2003 and July 2008 were included in the study. Resting 12-lead electrocardiogram was recorded. QT interval was measured manually and corrected using Bazett's formula. Patients were divided into groups with mild-to-moderate and severe pulmonary hypertension and a control group according to mean pulmonary arterial pressure.
  
  
  RESULTS
  In all observed cases, mean QTc was higher in severe pulmonary hypertension than in controls (428.6 +/- 32.8 ms vs. 411.1 +/- 28.4 ms, P = 0.018) and QTcd was higher in mild-to-moderate (60.1 +/- 17.2 ms) and severe pulmonary hypertension (63.9 +/- 20.5 ms) than in controls (47.3 +/- 10.6 ms) (P = 0.031; P = 0.004). In men, there was no significant difference in mean QTc and QTcd. In women, mean QTc was higher in severe pulmonary hypertension than in controls (436.1 +/- 39.4 ms vs. 407.6 +/- 24.8 ms, P = 0.037) and QTcd was higher in severe pulmonary hypertension (68.5 +/- 20.9 ms) than in both the controls (45.1 +/- 12.6 ms) and patients with mild-to-moderate pulmonary hypertension (58.6 +/- 14.7 ms) (P = 0.002; P = 0.003). In addition, in women with pulmonary hypertension, mean QTc and QTcd were positively correlated to mean pulmonary arterial pressure (r = 0.207, P = 0.03; r = 0.236, P = 0.012).
  
  
  CONCLUSIONS
  In women with pulmonary hypertension, mean QTc and QTcd are positively correlated to mean pulmonary arterial pressure and are significantly increased in patients with severe pulmonary hypertension.
authors: Fuwai Hospital & Cardiovascular Institute, Chinese Academy of Medical Sciences, Beijing, China.
authors: Zhang
authors: Z
authors: Hong-liang
authors: Luo
authors: L
authors: Qin
authors: Liu
authors: L
authors: Zhi-hong
authors: Zhao
authors: Z
authors: Zhi-hui
authors: Xiong
authors: X
authors: Chang-ming
authors: Ni
authors: N
authors: Xin-hai
authors: He
authors: H
authors: Jian-guo
authors: Wei
authors: W
authors: Ying-jie
authors: Zhang
authors: Z
authors: Shu
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D015992:Body Mass Index; D002681:China; D016757:Death, Sudden, Cardiac / Q000209:etiology; D004562:Electrocardiography; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D006976:Hypertension, Pulmonary / Q000175:diagnosis / Q000503:physiopathology*; D008133:Long QT Syndrome / Q000175:diagnosis / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D011669:Pulmonary Wedge Pressure / Q000502:physiology; D012307:Risk Factors; D012737:Sex Factors; D012815:Signal Processing, Computer-Assisted; D017180:Tachycardia, Ventricular / Q000175:diagnosis / Q000503:physiopathology