A novel tool to assess systolic asynchrony and identify responders of cardiac resynchronization therapy by tissue synchronization imaging.
ABSTRACT This study was designed to investigate if tissue synchronization imaging (TSI) is useful to identify regional wall delay and predict left ventricular (LV) reverse remodeling after cardiac resynchronization therapy (CRT).
Echocardiographic assessment of systolic asynchrony is helpful to predict a positive response to CRT. Tissue synchronization imaging is a new imaging technique that allows quick evaluation of regional systolic delay.
Tissue synchronization imaging was performed in 56 heart failure patients at baseline and three months after CRT. Regional wall delay was identified on TSI images and the time to regional peak systolic velocity (Ts) in LV was measured by the six-basal-six-mid-segmental model. Eight TSI parameters of systolic asynchrony were computed when Ts was measured in ejection phase or also included postsystolic shortening.
Severe lateral wall delay occurred in 17 patients, which predicted LV reverse remodeling (chi-square = 8.13, p = 0.004). Among the eight quantitative parameters of asynchrony, the predictive values were higher for parameters that measured Ts in ejection phase than in postsystolic shortening. The standard deviation of Ts of 12 LV segments in ejection phase (Ts-SD-12-ejection) was most powerful to predict reverse remodeling (r = -0.61, p < 0.001) and gain in ejection fraction (r = 0.53, p < 0.001). The area of the receiver-operating characteristic (ROC) curve was the largest for Ts-SD-12-ejection (0.90, p < 0.001), with a sensitivity of 87% and specificity of 81% at a cutoff of 34.4 ms. The combination of lateral wall delay with Ts-SD-12-ejection gave a sensitivity and specificity of 82% and 87%.
Tissue synchronization imaging allows quick evaluation of regional wall delay, and combined with Ts-SD-12-ejection provides a reliable way of predicting reverse remodeling after CRT.
Article: A modified echocardiographic protocol with intrinsic plausibility control to determine intraventricular asynchrony based on TDI and TSI.[show abstract] [hide abstract]
ABSTRACT: Established methods to determine asynchrony suffer from high intra- and interobserver variability and failed to improve patient selection for cardiac resynchronization therapy (CRT). Thus, there is a need for easy and robust approaches to reliably assess cardiac asynchrony. We performed echocardiography in 100 healthy subjects and 33 patients with left bundle branch block (LBBB). To detect intraventricular asynchrony, we combined two established methods, i.e., tissue synchronization imaging (TSI) and tissue Doppler imaging (TDI). The time intervals from the onset of aortic valve opening (AVO) to the peak systolic velocity (S') were measured separately in six basal segments in the apical four-, two-, and three-chamber view. Color-coded TSI served as an intrinsic plausibility control and helped to identify the correct S' measuring point in the TDI curves. Next, we identified the segment with the shortest AVO-S' interval. Since this segment most likely represents vital and intact myocardium it served as a reference for other segments. Segments were considered asynchronous when the delay between the segment in question and the reference segment was above the upper limit of normal delays derived from the control population. Intra- and interobserver variability were 7.0% and 7.7%, respectively. Our results suggest that combination of TDI and TSI with intrinsic plausibility control improves intra- and interobserver variability and allows easy and reliable assessment of cardiac asynchrony.Cardiovascular Ultrasound 09/2009; 7:46. · 1.26 Impact Factor
Article: Circumferential myocardial strain in cardiomyopathy with and without left bundle branch block.[show abstract] [hide abstract]
ABSTRACT: Cardiac resynchronization therapy (CRT) has been shown to decrease mortality in 60-70% of advanced heart failure patients with left bundle branch block (LBBB) and QRS duration > 120 ms. There have been intense efforts to find reproducible non-invasive parameters to predict CRT response. We hypothesized that different left ventricular contraction patterns may exist in LBBB patients with depressed systolic function and applied tagged cardiovascular magnetic resonance (CMR) to assess circumferential strain in this population. We determined myocardial circumferential strain at the basal, mid, and apical ventricular level in 35 subjects (10 with ischemic cardiomyopathy, 15 with non-ischemic cardiomyopathy, and 10 healthy controls). Patterns of circumferential strain were analyzed. Time to peak systolic circumferential strain in each of the 6 segments in all three ventricular slices and the standard deviation of time to peak strain in the basal and mid ventricular slices were determined. Dyskinesis of the anterior septum and the inferior septum in at least two ventricular levels was seen in 50% (5 out of 10) of LBBB patients while 30% had isolated dyskinesis of the anteroseptum, and 20% had no dyskinesis in any segments, similar to all of the non-LBBB patients and healthy controls. Peak circumferential strain shortening was significantly reduced in all cardiomyopathy patients at the mid-ventricular level (LBBB 9 +/- 6%, non-LBBB 10 +/- 4% vs. healthy 19 +/- 4%; both p < 0.0001 compared to healthy), but was similar among the LBBB and non-LBBB groups (p = 0.20). The LBBB group had significantly greater dyssynchrony compared to the non-LBBB group and healthy controls assessed by opposing wall delays and 12-segment standard deviation (LBBB 164 +/- 30 ms vs. non-LBBB 70 +/- 17 ms (p < 0.0001), non-LBBB vs. healthy 65 +/- 17 ms (p = 0.47)). Septal dyskinesis exists in some patients with LBBB. Myocardial circumferential strain analysis enables detailed characterization of contraction patterns, strengths, and timing in cardiomyopathy patients with and without LBBB.Journal of Cardiovascular Magnetic Resonance 01/2010; 12:2. · 3.72 Impact Factor
Article: Assessment of Left Ventricular Dyssynchrony in Heart Failure Patients Regarding Underlying Etiology and QRS Duration.[show abstract] [hide abstract]
ABSTRACT: Left ventricular (LV) dyssynchrony is a prevalent feature in heart failure (HF) patients. The current study aimed to evaluate the prevalence of inter and intraventricular dyssynchrony in HF patients with regard to the QRS duration and etiology. The available data on the tissue Doppler imaging (TDI) of 230 patients with refractory HF were analyzed. The patients were divided into three groups according to the QRS duration: QRS duration < 120 ms; 120-150 ms; and ≥ 150 ms and the patients were re-categorized into two subgroups depending on the underlying etiology: ischemic cardiomyopathy (ICM) or dilated cardiomyopathy (DCM). The time-to-peak myocardial sustained systolic velocity (Ts) in six basal and six middle segments of the LV was measured manually using the velocity curves from TDI. LV dyssynchrony was defined as interventricular mechanical delay ≥ 40 ms and tissue Doppler velocity all segments delay ≥ 105 ms; standard deviation (SD) of all segments ≥ 34.4 ms; basal segments delay ≥ 78 ms; SD of basal segments ≥ 34.5 ms; and opposing wall delay ≥ 65 ms. After adjustment for the possible confounders, interventricular dyssynchrony was more prevalent in the patients with QRS duration ≥ 150 ms than in those with QRS duration 120-150 ms and < 120 ms. The patients with DCM also had a higher percentage of interventricular dyssynchrony than those with ICM in the wide QRS groups. Turning to the intraventricular dyssynchrony indices, the patients with QRS duration ≥ 150 ms and 120-150 ms revealed a significantly greater delay between Ts at the basal and all segments than did those with QRS duration < 120 ms, while etiology did not influence the frequency of these indices in each QRS group. The prevalence of both inter and intraventricular dyssynchrony indices was greater in the patients with wide QRS than in those with narrow QRS duration. The underlying etiology may affect the frequency of interventricular but not intraventricular dyssynchrony indices.Journal of Tehran University Heart Center 11/2011; 6(4):193-201.