Increases in repolarization heterogeneity predict left ventricular systolic dysfunction and response to cardiac resynchronization therapy in patients with left bundle branch block

Abstract

Introduction This study aimed to investigate the association between T‐wave morphology and impaired left ventricular ejection fraction (LVEF) in patients with complete left bundle branch block (cLBBB), and the predictive value of T‐wave morphology for response to cardiac resynchronization therapy (CRT). Methods and Results We enrolled 189 patients with cLBBB on electrocardiogram performed between January 2007 and December 2011 who underwent standard echocardiography. Repolarization parameters, including the QRS‐to‐T angle (TCRT), T‐wave morphology dispersion (TMD), T‐wave loop area (PL), and T‐wave residuum (TWR), were reconstructed from digital standard 12‐lead electrocardiograms by T‐wave morphology analysis. CRT response was defined as ≥15% reduction in left ventricular end‐systolic volume at 12 months after CRT implantation. The clinical outcome endpoint was a composite of heart failure hospitalization, heart transplantation, or death during follow up (mean, 5.8 years). On logistic regression, a higher heart rate, longer QRS duration, increased TMD, and larger TWR were all independently associated with LVEF < 40%. Among 40 patients who underwent CRT, those with a larger TMD (P = .007), larger PL (P = .025), and more negative TCRT (P = .015) had better response to CRT. A large TMD (P = .018) and large PL (P = .003) were also independent predictors of the clinical outcome endpoint. Conclusions Increases in repolarization heterogeneity in patients with cLBBB are associated with impaired LVEF. A large TMD and large PL may be useful as additional predictors of response to CRT, improving patient selection for CRT.

Changes of repolarization parameters after left bundle branch area pacing and the association with echocardiographic response in heart failure patients

“…Sauer et al reported an independent relationship between TpTe and radial SD-tPkS (measuring contraction duration heterogeneity on echocardiography) ( Sauer et al, 2014 ). In addition, DVR was found to be significantly correlated with impaired LVEF ( Huang H. C. et al, 2020 ). However, whether repolarization parameters were associated with LBBAP response remains unclear.…”

Use of T-wave duration and Tpeak-Tend interval as new prognostic markers for patients treated with cardiac resynchronization therapy

“…For this reason, the T-wave and Tp-e interval, easily measurable ECG parameters, were taken into consideration. Despite the fact that there is no certain evidence that the increased T-wave duration implies an unfavorable CRT response, it was reported in the literature that the T-wave area and its morphology have been associated with prognosis in patients with HFrEF who underwent CRT [18,19]. In addition, new measurement methods that utilize automatic ECG programs such as absolute T-wave residuum, T-wave morphology dispersion and T-wave loop area, have been found to be effective in predicting the CRT response [19].…”

“…Despite the fact that there is no certain evidence that the increased T-wave duration implies an unfavorable CRT response, it was reported in the literature that the T-wave area and its morphology have been associated with prognosis in patients with HFrEF who underwent CRT [18,19]. In addition, new measurement methods that utilize automatic ECG programs such as absolute T-wave residuum, T-wave morphology dispersion and T-wave loop area, have been found to be effective in predicting the CRT response [19]. Nonetheless, these complex measurement methods need special computer programs and are difficult to be performed during the daily clinical practice when evaluating the CRT response at the bedside.…”

“…Engels et al demonstrated that in patients with LBBB morphology, a larger baseline T-wave area is a significant independent predictor of LVEF increase following CRT [18]. Huang et al demonstrated that HF patients with LBBB, larger T-wave morphology dispersion, larger T wave loop area, and more negative QRS-to-T angle had a better echocardiographic response to CRT [19]. Flore et al found that the absence of any changes in QRS duration and broader electrical remodeling (including the measurements of the angles between spatial QRS and T vectors before, during, and after CRT) are associated with notably better survival rates [23].…”

Outcomes with T‐wave discordance of left bundle branch block and preserved or mildly reduced ejection fraction

“…18 Ventricular repolarization heterogeneity has an important role in the development of HF, and several repolarization heterogeneity markers like the T-wave area, increased QRS-T angle, and T-wave morphology dispersion have been reported to have a prognostic impact on clinical outcomes. 19,20 Maffessanti et al found that discordant T waves in LBBB patients are explained by interventricular dispersion in repolarization by electro-anatomic mapping. 21 In our study, the presence of dLBBB was associated with a higher risk of cardiovascular death or non-fatal HF hospitalization.…”