title: [Effects of cardiac resynchronization therapy on  time-domain T wave alternans in patients with  chronic heart failure].
abstract: OBJECTIVE
  To study the effects of cardiac resynchronization therapy (CRT) with different pacing rates and modes on MTWA.
  
  
  METHODS
  From March, 2012 to October, 2014, 43 patients who received CRT or CRT-D implantation in the first affiliated hospital, Nanjing Medical University were studied. Time-domain MTWA test were assessed following CRT implantation. MTWA was measured at 90 min(-1) and 110 min(-1) by treadmill exercise test with GE CASE 8000 during CRT-on (BIV biventricular) and CRT-off (RA right atrial) pacing modes. The comparsion of MTWA values between different pacing mode and pacing rates were analyzed. According to the heart function classification the patients were divided into 3 groups. The correlation between MTWA and cardiac function was analyzed.
  
  
  RESULTS
  MTWA-AAI was significantly increased compared to MTWA-BIV at the pacing rate of 90 min(-1) [(11.27±9.94) µV vs (7.09±7.16) µV, P=0.001]. The value of MTWA at pacing rate of 110 min(-1) was nonsignificantly higher than MTWA during AAI pacing [(16.91±12.51) µV vs (15.58± 10.97) µV, P=0.517]. The value of MTWA at pacing rate of 110 min(-1) was higher than MTWA at pacing rate of 90 min(-1) during AAI or BIV (P<0.05). MTWA-AAI and MTWA-BIV in group of NYHA IV were higher than those in group of NYHA II (P<0.05).
  
  
  CONCLUSIONS
  Biventricular pacing mode at lower pacing rates can significantly attenuate MTWA. The value of MTWA is associated with the severity of CHF.
authors.affiliation: Department of Cardiology, First Affiliated Hospital, Nanjing Medical University, Nanjing 210029; Department of General Medicine, Jiangsu Province Hospital of Traditional Chinese Medicine, Nanjing University of Chinese Medicine, Nanjing 210029, China.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Tang
authors.affiliation: Department of Cardiology, First Affiliated Hospital, Nanjing Medical University, Nanjing 210029; Department of Cardiology, Taixing People's Hospital, Taixing Jiangsu 225400, China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Department of Cardiology, First Affiliated Hospital, Nanjing Medical University, Nanjing 210029, China.
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Hou
authors.affiliation: Department of Cardiology, First Affiliated Hospital, Nanjing Medical University, Nanjing 210029, China.
authors.forename: Quanpeng
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Department of Cardiology, First Affiliated Hospital, Nanjing Medical University, Nanjing 210029, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Zhang
authors.affiliation: Department of Cardiology, First Affiliated Hospital, Nanjing Medical University, Nanjing 210029, China.
authors.forename: Jiangang
authors.initials: J
authors.lastname: Zou
mesh_terms: D001145:Arrhythmias, Cardiac / Q000628:therapy*; D058406:Cardiac Resynchronization Therapy; D005080:Exercise Test; D006333:Heart Failure / Q000628:therapy*; D006801:Humans