To explore the predictive value of microvolt T-wave alternation (MTWA) for long-term ventricular tachyarrhythmia (VTA) after cardiac resynchronization therapy (CRT) .

This research was a diagnostic test research. This study enrolled 45 patients with chronic heart failure (CHF) who were successfully implanted with cardiac resynchronization therapy pacing (CRT-P) or cardiac resynchronization therapy defibrillator (CRT-D) from May 2010 to January 2015 in department of cardiology in the First Affiliated Hospital of Nanjing Medical University[mean age: (59.5±12.3) years old], including 33 males (73.3%, 33/45) . All patients underwent echocardiography and electrocardiogram preoperatively and 6 months postoperatively. MTWA values ​​were measured at a biventricular (BiV) pacing rate of 110 beats per minute within one week and six months after device implantation using modified moving average analyses. VTA events, including sustained ventricular tachycardia, ventricular fibrillation, anti-tachycardia pacing (ATP) or cardioversion (CV) or shock therapy were collected from the device. The average follow-up time was (55.3±34.2) months. According to the presence or absence of VTA events, all patients were divided into VTA group (Group A) and non-VTA group (Group B) .

①The effect of CRT on left ventricular ejection fraction (LVEF) and MTWA in CHF patients: a.The LVEF ​​of two groups were significantly improved at six-month follow-up than baseline[Group A: (36.8%±9.8%) vs. (30.0%±7.1%) , P=0.004; Group B: (44.1%±12.7%) vs. (31.5%±7.6%) , P<0.001]. ｂ. The MTWA value at six-month (MTWA2) decreased compared to the baseline MTWA (MTWA1) in two groups, but there was no statistical difference. ②The predictive value of MTWA for long-term VTA: a.The MTWA of Group A at baseline and six months was significantly higher than that of Group B[MTWA1: (26.6±21.0) μV vs. (11.4±6.8) μV,P=0.002; MTWA2: (19.0±15.4) μV vs. (9.8±10.0) μV, P=0.02) . b.Using 22 μV and 13 μV as the cut-off point for MTWA1 and MTWA2 respectively, all patients were divided into MTWA positive group and negative group. The probability of VTA in the MTWA positive group at baseline and six months was significantly greater than that in the MTWA negative group (baseline: P=0.002; six months after surgery: P=0.012) . The sensitivity of MTWA1 for predicting VTA events was 47.6%, and the specificity is 95.8%. The sensitivity of MTWA2 for predicting VTA events was 61.9 %, and the specificity was 75.0%. c.Log rank method was used to test the difference in time distribution of VTA occurrence. The time of occurrence of VTA in the MTWA1 positive group and MTWA2 positive group was significantly shorter than that of the negative group. d.Two-category Logistic regression was used to evaluate the effects of MTWA1, MTWA2 and LVEF on the occurrence of VTA. Both Logistic models showed that compared with LVEF, MTWA indicators had a better prediction for VTA.

MTWA has a good predictive value for the occurrence of long-term VTA in CRT patients.

Cardiac resynchronization therapy; Microvolt T-wave alternation; Ventricular tachyarrhythmia; Long-term follow-up; Chronic heart failure