Value of dual Doppler echocardiography for prediction of atrial fibrillation recurrence after radiofrequency catheter ablation.

BACKGROUND: Increasing evidence has been presented which suggests that left ventricular (LV) diastolic dysfunction may play an important role in the development of atrial fibrillation (AF). However, the potential for LV diastolic dysfunction to serve as a predictor of AF recurrence after radiofrequency catheter ablation remains unresolved. METHODS: Dual Doppler and M-PW mode echocardiography were performed in 67 patients with AF before ablation and 47 patients with sinus rhythm. The parameters measured within identical cardiac cycles included, the time interval between the onset of early transmitral flow peak velocity (E) and that of early diastolic mitral annular velocity (e') (TE-e'), the ratio of E to color M-mode Doppler flow propagation velocity (Vp)(E/Vp), the Tei index, the ratio of E and mitral annular septal (S) peak velocity in early diastolic E/e'(S) and the ratio of E and mitral annular lateral (L) peak velocity E/e'(L). A follow-up examination was performed 1 year after ablation and patients were divided into two groups based on the presence or absence of AF recurrence. Risk estimations for AF recurrence were performed using univariate and multivariate logistic regression. RESULTS: TE-e', E/Vp, the Tei index, E/e'(S) and E/e'(L) were all increased in AF patients as compared with the control group (p <  0.05). At the one-year follow-up examination, a recurrence of AF was observed in 21/67 (31.34%) patients. TE-e' and the Tei index within the recurrence group were significantly increased as compared to the group without recurrence (p <  0.001). Results from multivariate analysis revealed that TE-e' can provide an independent predictor for AF recurrence (p = 0.001). CONCLUSIONS: Dual Doppler echocardiography can provide an effective and accurate technique for evaluating LV diastolic function within AF patients. The TE-e' obtained within identical cardiac cycles can serve as an independent predictor for the recurrence of AF as determined at 1 year after ablation.

In situ ultrasound imaging of silk hydrogel degradation and neovascularization.

Ultrasound (US) is a useful technique to monitor morphological and functional changes of biomaterial implants without sacrificing the animal. Contrast-enhanced ultrasound (CEUS) along with two-dimensional (2D) US were used to characterize the biodegradation and neovascularization of silk protein (8 wt%) hydrogel implants in rats. Cylinder-shaped silk hydrogel plugs were implanted into the space between the hind limb thigh muscles in Wistar rats (n = 6). The increase of echogenicity in 2D US revealed tissue-ingrowth-accompanied gel degradation over 18 weeks. The shape and size of the implanted gels remained qualitatively unchanged until week 15, as confirmed by Bland and Altman analysis and visualization of retrieved samples. Using CEUS, neovascularization was monitored by the presence of microbubbles in the gel area, and the dynamic vascularization process was indicated by the contrast enhancement values, which showed a relatively low level (< 5 dB) during weeks 1-8 and significantly increased levels (around 20 dB at week 15 and > 35 dB at week 18), suggesting that major vascularization had occurred in the gel implants by this time point. Histological and scanning electron microscopic analysis of explants revealed time-dependent increases in the pore size of the gel matrix, the presence of endothelial and red blood cells and the number of blood vessels in the gel implants, indicating that degradation and vascularization did occur in silk gel implants during the time period. The present study demonstrates the use of US imaging for monitoring of in vivo degradation and vascularization of silk implants in a non-destructive way. Copyright © 2015 John Wiley & Sons, Ltd.

Three-Dimensional Speckle-Tracking Echocardiographic Monitoring of Acute Rejection in Heart Transplant Recipients.

OBJECTIVES: This study assessed the use of 3-dimensional (3D) speckle-tracking echocardiography for noninvasive monitoring and diagnosis of acute rejection in heart transplant recipients. METHODS: Fifteen heart transplant recipients underwent 32 endomyocardial biopsies; echocardiography was performed within 3 hours before biopsy. Twenty-four biopsies (acute rejection-negative group) showed grade 0 or 1A rejection, and 8 biopsies (acute rejection-positive group) showed grade 1B or higher rejection (based on the International Society for Heart and Lung Transplantation criteria). Two-dimensional, M-mode, pulsed Doppler, and tissue Doppler echocardiography were performed to assess conventional heart structure and function, and 3D full-volume echocardiography was recorded and analyzed. RESULTS: Global peak longitudinal strain was significantly lower in the acute rejection-negative group compared to the positive group (mean ± SD, -7.38% ± 1.34% versus -10.88% ± 3.81%; P = .017). Differences in left ventricular global peak radial strain (28.79% ± 10.79% versus 24.32% ± 5.24%; P= .272), global peak circumferential strain (-12.16% ± 4.87% versus -12.61% ± 2.38%; P = .806), and ejection fraction (49.42% ± 12.17% versus 50.68% ± 7.26%; P = .824) between the negative and positive groups were not significant. Significant correlations were observed between the left ventricular ejection fraction and global peak longitudinal, global peak radial, and global peak circumferential (r = -0.72; P < .001; r = 0.60; P < 0.001; and r = -0.69; P < 0.001, respectively). Receiver operating characteristic curve analysis showed that a global peak longitudinal strain cutoff value of less than -9.55% could predict grade 1B or higher rejection with sensitivity of 87.50% and specificity of 54.17%. CONCLUSIONS: Three-dimensional speckle-tracking echocardiography-derived global peak longitudinal strain is a useful parameter for detecting acute rejection; thus, 3D speckle-tracking echocardiography can monitor dynamic and acute rejection (≥1B) in heart transplant recipients.

Three-dimensional transesophageal echocardiographic study of aortic-mitral valve coupling after coronary artery bypass grafting.

AIMS: To observe the geometric changes in aortic-mitral valve coupling (AMC) on three-dimensional transesophageal echocardiography and the factors leading to decreased mitral regurgitation (MR) after coronary artery bypass grafting (CABG). METHODS AND RESULTS: This study included 23 patients undergoing CABG for coronary artery disease. Fifteen patients with moderate to severe MR were separately analyzed to determine whether the severity of MR influences the geometric change in AMC. Echocardiographic examinations were performed pre- and post-CABG, and the studied parameters were obtained using Siemens Auto Valve Analysis software. The effective mitral regurgitant orifice area, left ventricular ejection fraction (LVEF), end-diastolic volume (EDV), and end-systolic volume (ESV) were measured pre- and post-CABG using Philips QLAB software. Ischemic MR, EDV, and ESV significantly decreased (all P < 0.05) and LVEF significantly improved (P < 0.05) after CABG. There were no significant differences between the pre- and post-CABG mitral valve (MV) parameters, aortic valve parameters, aortic-mitral annular angle, or centroid distance (all P > 0.05). Patients with moderate to severe MR exhibited the same results. CONCLUSION: The results of this study show that CABG does not cause an acute change in the geometry of AMC. Improved left ventricular function might increase the closing force of the MV, leading to decreased MR after CABG alone. MR significantly improved after CABG alone without MV treatment in the present study. This result may help to guide surgeons in choosing the optimal surgical methods for individual patients.