Editorials
Usefulness of Tissue Doppler Imaging-Derived Atrial Conduction Time for Prediction of Atrial Fibrillation
2016 Volume 80 Issue 1 Pages 58-59
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2016 Volume 80 Issue 1 Pages 58-59
Vulnerability to atrial fibrillation (AF) associates the atrial condition with the critical number of wavelets and multiple reentrant circuits resulting in delayed intra-atrial conduction.1,2 Total atrial conduction time (TACT), representing the total time required for atrial electrical activation, can be evaluated as the maximal P-wave duration using single-averaged electrocardiogram (SA-ECG), and is reported to be a powerful predictor of AF.3,4 However, this method of measuring TACT is difficult to use in clinical practice because of its time-consuming technique and requirement for special hardware. Merckx et al described an alternative echocardiographic measurement using tissue Doppler imaging (TDI) to estimate TACT. They measured the time from the initiation of atrial depolarization represented by the onset of the P-wave on the 12-lead surface ECG (lead II) until the last atrial depolarization represented by the peak of TDI A’ wave at the left atrial (LA) lateral wall (Figure). They also demonstrated that this TDI-derived atrial conduction time (PA-TDI duration) using echocardiography equipment5 had the best correlation with TACT measured by SA-ECG. Furthermore, PA-TDI duration also enables practical and better prediction of new-onset AF,6 recurrence after AF ablation7 and AF after acute myocardial infarction8 compared with LA volume or other parameters.
Measurement of tissue Doppler imaging-derived atrial conduction time (PA-TDI duration).
Article p 101
Postoperative AF is one of the most common complications after cardiac surgery,9 and 94% of cases are prone to occur up till postoperative day 6.10 Recently, the prediction of AF after off-pump coronary artery bypass grafting (CABG),11 and aortic valve replacement (AVR) for aortic valve stenosis (AS) using PA-TDI duration was reported.12
In this issue of the Journal, Takahashi et al13 investigate the prediction of postoperative AF after mitral valve surgery (MVS) for mitral valve regurgitation (MR) using TDI-derived atrial conduction time. MR is one of the representative valvular heart diseases associated with a large LA. Therefore, new-onset AF after MVS and disappearance of the MR jet may facilitate the formation of LA thrombosis and increase the risk of stroke compared with other cardiac surgery. The important findings from their study are as follows.
Firstly, the overall incidence of postoperative AF was 60% (44 of 73 patients) and a relatively high incidence. The criteria of postoperative AF in this study was AF lasting >5 min. All patients were monitored with continuous ECG telemetry for ≥2 weeks following MVS. The current study was able to detect new-onset of AF without fail compared with previous reports.6–8 Secondly, under univariate analysis of prediction for postoperative AF, a degenerative MR, the duration of MR, A-wave peak velocity, PA-TDI duration and preoperative CVP were significant predictors of postoperative AF. Multivariate analysis demonstrated that degenerative MR (95% confidence interval (CI): 1.41–15, P=0.0112) and PA-TDI duration (95% CI: 1.01–1.07, P=0.0048) were significant and independent predictors of postoperative AF. The reason for the poor association of LA volume parameters and postoperative AF in this study was the larger LA volume in both the AF and non-AF groups (LA volume index, AF 58.7±20.6 ml/m2 vs. Non-AF 53.4±16.2 ml/m2 P=0.27).
The current results were a little different from previous reports analyzing patients after off-pump CABG11 or AVR.12 Multivariate analysis demonstrated that postoperative AF after off-pump CABG was significantly associated with the LA volume index (95% CI: 1.02–1.20, P=0.01) and PA-TDI duration (95% CI: 1.06–1.16, P=0.0001). On the other hand, postoperative AF after AVR for AS had a significant association with age (95% CI: 1.03–1.28, P=0.016) and PA-TDI duration (95% CI: 1.02–1.13, P=0.0072).
PA-TDI duration has been proven to be a predictor of postoperative or new-onset AF in various situations (Table). Previous and current studies each show their cut-off value of PA-TDI duration for predicting AF. The current study would also contribute to the clinical utility of PA-TDI duration as a predictor for postoperative AF in patients after MVS for MR.
| No. of patients | PA-TDI duration (ms) | ||||
|---|---|---|---|---|---|
| Postoperative (new-onset) |
AF | Non-AF | Cut-off (AUC) | ||
| AF (%)/ non-AF | |||||
| de Vos et al6 (2009) | New-onset AF 680±290 days follow-up |
15 (6)/234 | 172±25 | 150±20* | 165 (0.74) |
| Antoni et al8 (2010) | New-onset AF after AMI 21±13 months follow-up |
38 (6)/575 | 138±29 | 109±16† | 127 (0.84) |
| den Uijl et al7 (2011) | Recurrence after AF ablation 13±3 months follow-up |
74 (35)/139 | 146±20 | 124±23† | − (0.765) |
| Fujiwara et al11 (2014) | AF after cardiac surgery (Off-pump CABG) 1 week follow-up |
35 (40)/53 | 156±20 | 128±15‡ | 141 (0.85) |
| Takahashi et al12 (2014) | AF after cardiac surgery (AVR for AS), ≥1 week follow-up |
41 (65)/22 | 155±19 | 137±13§ | 147.3 (0.804) |
| Takahashi et al13 (2015) | AF after cardiac surgery (MVS for MR), ≥2 weeks follow-up |
44 (60)/29 | 159±22 | 141±20† | 159.4 (0.737) |
*P=0.001, †P<0.001, ‡P=0.0001, §P<0.01 vs. new-onset AF. AF, atrial fibrillation; AMI, acute myocardial infarction; AS, aortic stenosis; AUC, area under curve; AVR, aortic valve replacement; CABG, coronary artery bypass grafting; MR, mitral valve regurgitation; MVS, mitral valve surgery.
