Cardiac resynchronization therapy reduces T-wave alternans in patients with heart failure.
OBJECTIVE
T-wave alternans (TWA) represents myocardial instability. The present study was to determine the impact of cardiac resynchronization therapy (CRT) on TWA and left ventricular ejection fraction (LVEF) in heart failure patients.


RESULTS
T-wave alternans was analysed using a spectral method in 27 CRT-ICD patients. Ambulatory device electrograms were collected and LVEF and New York Heart Association (NYHA) classification were assessed at baseline prior to CRT and 3 months following CRT. Patients were followed for 6 months to monitor cardiac events. Spectral TWA of device electrograms was measured during AAI and CRT pacing tests. Each pacing mode had the up-titration pacing rate from 90 to 105 b.p.m. with 90 s for each pacing rate. At baseline, 20 (76.9%) patients had TWA during AAI pacing tests and 13 (50%) during CRT pacing tests (P = 0.044 between two pacing modes). Following 3-month CRT, TWA was identified in 11 patients (45.8%) during AAI pacing tests (a 31.1% reduction from the baseline value, P = 0.023) and 7 patients (28%) during CRT pacing tests (a 22% reduction, P = 0.108). Six of seven patients who had cardiac events had TWA (three patients had arrhythmic events, two died of heart failure, one received heart transplant). Overall, LVEF improved from 27.3 ± 5.8 to 35.9 ± 10.5% (P < 0.001) and NYHA classification improved from 2.8 ± 0.6 to 1.6 ± 0.6 after 3-month CRT (P < 0.001).


CONCLUSIONS
In heart failure patients who receive a CRT-ICD, CRT reduces TWA that is associated to cardiac events, suggesting that CRT promotes clinically significant reverse electrical and mechanical remodelling.
Arrhythmic Center and Clinical EP Lab, Beijing Fuwai Hospital and National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, 167 Beilishilu, Beijing 100037, China.
Wei
W
Hua
Arrhythmic Center and Clinical EP Lab, Beijing Fuwai Hospital and National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, 167 Beilishilu, Beijing 100037, China.
Keping
K
Chen
CRDM, Medtronic (Shanghai) Management Co., Ltd., Blk 11, No. 3000 Long Dong Ave, Shanghai 201203, China.
Xiaohong
X
Zhou
Arrhythmic Center and Clinical EP Lab, Beijing Fuwai Hospital and National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, 167 Beilishilu, Beijing 100037, China.
Yan
Y
Dai
Arrhythmic Center and Clinical EP Lab, Beijing Fuwai Hospital and National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, 167 Beilishilu, Beijing 100037, China.
Ruohan
R
Chen
Arrhythmic Center and Clinical EP Lab, Beijing Fuwai Hospital and National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, 167 Beilishilu, Beijing 100037, China.
Jing
J
Wang
Arrhythmic Center and Clinical EP Lab, Beijing Fuwai Hospital and National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, 167 Beilishilu, Beijing 100037, China.
Ligang
L
Ding
Arrhythmic Center and Clinical EP Lab, Beijing Fuwai Hospital and National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, 167 Beilishilu, Beijing 100037, China.
Zhiming
Z
Liu
Arrhythmic Center and Clinical EP Lab, Beijing Fuwai Hospital and National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, 167 Beilishilu, Beijing 100037, China.
Tianjie
T
Feng
Arrhythmic Center and Clinical EP Lab, Beijing Fuwai Hospital and National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, 167 Beilishilu, Beijing 100037, China.
Jun
J
Yu
CRDM, Medtronic (Shanghai) Management Co., Ltd., Blk 11, No. 3000 Long Dong Ave, Shanghai 201203, China.
Jianwei
J
Cheng
CRDM, Medtronic (Shanghai) Management Co., Ltd., Blk 11, No. 3000 Long Dong Ave, Shanghai 201203, China.
Cherry
C
Liu
Arrhythmic Center and Clinical EP Lab, Beijing Fuwai Hospital and National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, 167 Beilishilu, Beijing 100037, China zsfuwai@vip.163.com.
Shu
S
Zhang
D000368:Aged; D058406:Cardiac Resynchronization Therapy / Q000379:methods*; D058409:Cardiac Resynchronization Therapy Devices; D015331:Cohort Studies; D017147:Defibrillators, Implantable; D004562:Electrocardiography; D015716:Electrocardiography, Ambulatory; D005260:Female; D006333:Heart Failure / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D013318:Stroke Volume; D017180:Tachycardia, Ventricular / Q000503:physiopathology; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000503:physiopathology / Q000628:therapy*; D014693:Ventricular Fibrillation / Q000503:physiopathology
Cardiac resynchronization therapy; Chronic heart failure; Implantable cardioverter-defibrillator; T-wave alternans; Ventricular tachyarrhythmia