Global Peak Circumferential Strain Research Articles

Ventricular strain is compromised outside of the coronary autoregulatory range – assessment by cardiovascular magnetic resonance

Introduction Coronary autoregulation maintains near-constant myocardial blood flow in a range of approximately 60-140 mmHg of mean arterial pressure (MAP). Using oxygenation-sensitive (OS) cardiovascular magnetic resonance (CMR), we showed that myocardial oxygenation is compromised at MAP levels below the lower limit of this range. Above its upper limit we observed luxury perfusion and mild oxygen excess. There is a lack of data exploring the relationship between coronary autoregulation, myocardial oxygenation and ventricular function. CMR feature tracking software allows to quantify myocardial deformation and strain in OS images. Our aim was to explore our data from an animal study for associations between myocardial function, myocardial oxygenation and coronary blood flow (CBF) over a wide range of MAP levels. Methods In ten anaesthetized swine a flow probe was surgically attached to the proximal left anterior descending coronary artery before the animals were placed into a 3 Tesla MRI scanner. Starting from a baseline of 70 mmHg, MAP was varied in steps of 10-15 mmHg using phenylephrine and urapidil, respectively. At each MAP level, OS cine images and CBF readings of the anterior descending coronary artery were obtained, as well as arterial and coronary sinus blood gas samples to determine myocardial oxygen extraction ratio. Using feature tracking-software, strain data were acquired from images by tracing endo- and epicardial contours in end-diastole, from which peak global circumferential strain (GCS) was calculated for both ventricles. The relationships of peak GCS to MAP, CBF and myocardial oxygenation were established. Results We analysed 101 MAP levels, which ranged between 35 and 196 mmHg. Oxygenation as assessed by OS-CMR showed a curvi-linear relationship to MAP, with a steeper decrease below the lower limit of the autoregulatory range and an increase above its upper limit. Peak GCS of both ventricles became progressively impacted when MAP was forced from its baseline (70 mmHg) towards and beyond the lower and upper autoregulatory limit (dashed yellow lines in figure). There was no apparent association between changes of peak GCS and CBF. GCS of left ventricular myocardium decreased linearly with increasing myocardial oxygen extraction ratio (r=0.261, p=0.026), and in a non-linear fashion with decreasing myocardial tissue oxygenation. Discussion In a porcine model with non-diseased hearts, biventricular systolic function becomes compromised when MAP reaches levels either below or above coronary autoregulatory limits. Contractile dysfunction at pressures below the lower limit appears to be caused by myocardial deoxygenation. Conversely, hypertension-induced systolic dysfunction is associated with increased coronary flow and oxygen excess, which points to high afterload rather than O2 demand/supply imbalance as the most likely mechanism. We conclude that in hearts without coronary disease, global strain abnormalities elicited by hypotensive or hypertensive stress also differ in their underlying pathophysiological mechanisms.

Effects of normoxic versus hyperoxic hyperventilation followed by apnea on right ventricular strain in patients with multi-vessel coronary artery disease

Introduction Hypocapnia and hyperoxia are coronary vasoconstrictors, whereas hypercapnia acts as a coronary vasodilator. Prior to anaesthetic induction, patients receive a FiO2 of 1.0 and are asked to take deep breaths. Resulting hyperoxic hypocapnia may be aggravated by excessive manual ventilation. Subsequent apnea during intubation increases paCO2. So far it remains unclear whether and how such rapid blood gas alterations impact right ventricular (RV) function, especially so in the presence of coronary artery disease (CAD). Cardiovascular magnetic resonance (CMR) imaging is useful to assess subtle changes of myocardial function and constitutes the gold standard for RV imaging. The objective of this CMR study is to compare RV function of healthy persons and patients with CAD during a typical hyperventilation-apnea maneuver. Methods Ten healthy participants and 25 patients with stable, well-defined multi-vessel CAD underwent a CMR study. After baseline imaging at room air, subjects hyperventilated for 60 seconds (HV) and then maintained apnea for 30s. Cine images of two ventricular short axis slices were acquired at baseline and from the end of HV throughout the breath-hold. After reequilibration, participants breathed oxygen (10L/min) for 5 minutes via a non-rebreathing mask and repeated the same respiratory maneuver under oxygen inhalation. CMR cine images were analyzed for RV global peak circumferential strain (RVGCS) for each group and condition. Results Healthy participants showed no significant RVGCS changes within or between normoxic or hyperoxic respiratory maneuvres, although HV enhanced strain numerically. CAD patients showed significant attenuation of RVGCS at the end of the hyperoxic HV-apnea sequence (baseline, -13.5±4.7 % vs. hyperoxic apnea, -11.8±4.9 %; p= 0.047), but not after the respective sequence at room air (-13.8±4.1%, p=0.611). In 20% of the CAD patients the hyperoxic HV-apnea sequence attenuated RVGCS by more than 5% from normoxic baseline. The figure shows RVGCS of both groups during the maneuver (more negative numbers representing better systolic contractile function, i.e., circumferential shortening). Discussion At the conclusion of an induced respiratory maneuver, which resembles a hyperoxic anaesthesia induction sequence, awake CAD patients exhibit significant attenuation of RV peak circumferential strain. This response could be haemodynamically relevant during anaesthesia induction in high-risk CAD patients and needs to be investigated further in a scenario of general anaesthesia.

Strain analysis using feature tracking cardiac magnetic resonance (FT-CMR) in the assessment of myocardial viability in chronic ischemic patients.

The purpose of this study is totest the capability of a commercially available feature tracking-cardiac magnetic resonance (FT-CMR) strain analysis software module in differentiating between viable and non-viable myocardium in chronic ischemic patients. Thirty chronic ischemic patients and 10 healthy volunteers were enrolled. Cine images were used for peak circumferential and radial strains quantification using dedicated FT-CMR software. Global strain was compared between patients and controls. In patients, segmental strain was compared in viable and non-viable myocardium determined by late gadolinium enhancement (LGE); and in segments with wall abnormalities. Among 480 myocardial segments analyzed in patients, 76 segments were non-viable on LGE. The mean left ventricular ejection fraction (LVEF) of the patients (87% males, mean age 55 ± 12years) was 40 ± 12% vs. 61 ± 5% for the controls (80% males, mean age 39 ± 11years). Peak global circumferential strain (GCS) and global radial strain (GRS) were significantly impaired in patients compared to controls (-13.89 ± 4.12% vs. -19.84 ± 1.47%), p < 0.001 and (23.11 ± 6.59% vs. 31.72 ± 5.52%), p = 0.001. Segmental circumferential strain (SCS) and segmental radial strain (SRS) were significantly impaired in non-viable compared to viable segments (-9.47 ± 7.26% vs. -14.72 ± 7.5%), p < 0.001 and (15.67 ± 12.11% vs. 24.51 ± 16.22%), p < 0.001. Cut-off points of -9.36% for the SCS (AUC = 0.7, 95% CI = 0.63-0.77) and 19.5% for the SRS (AUC = 0.67, 95%CI = 0.61-0.73) were attained above which the segment is considered viable.SCS was able to discriminate between normokinetic, hypokinetic and akinetic segments (mean = 27.6 ± 17.13%, 18.66 ± 12.88% and 15.24 ± 10.70% respectively, p < 0.001). Circumferential and radial segmental strain analysis by FT-CMR was able to discriminate between viable and non-viable segments of the myocardium defined by LGE and between normokinetic, hypokinetic and akinetic segments, using routinely acquired cine images, and thus can provide a more objective metric for risk stratification in chronic ischemic patients.

Associations of B-type natriuretic peptide (BNP) and dialysis vintage with CMRI-derived cardiac indices in stable hemodialysis patients with a preserved left ventricular ejection fraction.

To assess left ventricular myocardial native T1/T2 values and systolic strain and their associations with B-type natriuretic peptide (BNP) and dialysis vintage in hemodialysis (HD) patients with a preserved left ventricular ejection fraction (LVEF). Forty-three HD patients with end-stage renal disease (ESRD) but a preserved LVEF (≥ 50%) and 28 healthy volunteers were enrolled. BNP was measured at the time of cardiac magnetic resonance (CMR) measurements. Global native T1 and T2 values were significantly higher in the HD patients (native T1: 1056 ± 32ms vs. 1006 ± 25ms, p < 0.001; T2: 50 ± 3ms vs. 46 ± 2ms, p < 0.001) than in the controls. The mean peak global circumferential strain (GCS) and global longitudinal strain (GLS) were both significantly reduced in the HD patients compared with the controls (GCS: - 13 ± 3 vs. - 16 ± 3, p < 0.001; GLS: - 12 ± 4 vs. - 15 ± 3, p = 0.001). In the HD patients, the global native T1 value showed a positive correlation with the global T2 value (r = 0.311, p = 0.042) and significant correlations with GCS (r = 0.564, p < 0.001) and GLS (r = 0.359, p = 0.018). Significant positive correlations were found between lg BNP levels and T2 values (r = 0.569, p < 0.0001) and the left atrial volume index (LAVI) (r = 0.536, p = 0.012). GLS showed significant positive correlations with the LVMI (r = 0.354, p = 0.020) and dialysis vintage (p = 0.026; r = - 0.339) in the HD patients. HD patients with a preserved LVEF have increased native T1/T2 values and decreased strain compared to controls. T2 values and the LVAI were positively associated with BNP in HD patients.

Evaluation of left ventricular strain in patients with arrhythmia based on the 3T MR temporal parallel acquisition technique

Most of the current studies on myocardial strain are mainly applied in patients with sinus rhythm because the image quality of arrhythmias obtained with conventional scanning sequences does not meet diagnostic needs. Here, we intend to assess left ventricular (LV) global myocardial strain in patients with arrhythmias with 3 Tesla magnetic resonance (MR) and a new cine sequence. Thirty-three patients with arrhythmia and forty-eight subjects with sinus rhythm were enrolled in the study. LV myocardial thickness, cardiac function, myocardial strain and the apparent contrast-to-noise ratio (CNR) were all measured and compared using images generated by the real-time temporal parallel acquisition technique (TPAT) and the conventional cine sequence. In the arrhythmia group, the image quality of real-time TPAT was significantly better than that of the conventional cine sequence. In the arrhythmia group, the LV global peak radial strain and global peak circumferential strain values of real-time TPAT were significantly different from those of the conventional technique (radial strain, conventional: 20.27 ± 15.39 vs. TPAT: 24.14 ± 15.85, p = 0.007; circumferential strain, conventional:−12.06 ± 6.60 vs. TPAT: −13.71 ± 6.31, p = 0.015). There was no significant difference in global peak longitudinal strain between real-time TPAT and the conventional technique (−10.94 ± 4.66 vs. −10.70 ± 5.96, p = 0.771). There was no significant difference in the cardiac function parameters between the two techniques (p > 0.05), but there was a significant difference in 12 segments of the LV wall thickness between the two sequences (p < 0.05). In the sinus rhythm group, image quality using real-time TPAT was comparable to that using the conventional technique, and there was no significant difference in any of the indices (p > 0.05). Real-time TPAT is an effective method for detection of left ventricular myocardial deformation in patients with arrhythmia.

Cardiac Magnetic Resonance Feature Tracking: A Novel Method to Assess Left Ventricular Three-Dimensional Strain Mechanics After Chronic Myocardial Infarction

This study was designed to assess left ventricular deformation after chronic myocardial infarction (CMI) using cardiac magnetic resonance feature tracking (CMR-FT) technology, and analyze its relationship with left ventricular ejection fraction (LVEF) and infarcted transmurality. Ninety-six patients with CMI and 72 controls underwent 3.0 T CMR scanning. Strain parameters were measured by dedicated software, including global peak longitudinal strain (GPLS), global peak circumferential strain (GPCS), global peak radial strain (GPRS), segmental peak longitudinal strain (PLS), peak circumferential strain (PCS), and peak radial strain (PRS). All enhanced myocardium segments were divided into subendocardial infarction (SI) and transmural infarction (TI) group. Pearson, intraclass correlation coefficient and receiver operating characteristic analysis were performed to compare the parameters' mean values between SI and TI groups. GPLS, GPRS, and GPCS in CMI group were significantly decreased comparing with control group. PRS and PCS in TI group were significantly lower than those in SI group, whereas no statistical difference was observed in PLS. In Pearson correlation analysis, LVEF was strongly correlated with GPLS, GPRS, and GPCS in CMI patients. Additionally, excellent reproducibility of all strain parameters was observed. In receiver operating characteristic analysis, segmental PRS and PCS might differentiate SI from TI with higher diagnostic efficiency (p < 0.05), while PLS was less valuable (p > 0.05). CMR-FT could noninvasively and quantitatively assess global and regional myocardial strain in CMI patients with excellent reproducibility and strong correlation with LVEF. Additionally, segmental myocardial strain parameters indicate potential clinical value in differentiating myocardial infarction subtype.

The prognostic value of right ventricular deformation derived from cardiac magnetic resonance tissue tracking for all-cause mortality in light-chain amyloidosis patients.

Early detection of right ventricular (RV) dysfunction is vital for determining the prognosis of light-chain amyloidosis (AL) patients. While few studies focused on RV deformation due to the limitation of research methods. The aim of this study was to determine the prognostic significance of RV myocardial strain in AL patients assessed by cardiac magnetic resonance (CMR) tissue tracking. Sixty-four AL patients (28 females and 36 males, mean age 58±12.8 years old; range 25-81 years old) were enrolled from 1 October 2014 through 31 March 2017 and compared with 20 age- and sex-matched controls. Fifty-one AL patients met the criteria for cardiac amyloidosis (CA). Deformation parameters of both RV and left ventricle (LV) were measured by the CMR tissue tracking technique including myocardial global radial peak strain (GRPS), global circumferential peak strain (GCPS), and global longitudinal peak strain (GLPS). The follow-up time was 20 months or until the occurrence of death. Thirty-two (50%) had preserved RV ejection fraction (RVEF ≥45%). AL patients had significantly lower RV-GRPS (20.3±2.12 vs. 31.31±7.61), GCPS (-2.12±0.88 vs. -13.71±2.53), and GLPS (-5.33±0.64 vs. -14.239±2.99) than controls even RVEF remain preserved (all P<0.001). Compared with controls and patients without CA, RV-GRPS (12.26±1.26 vs. 29.72±3.54, P<0.001) and RV-GLPS (-3.78±2.25 vs. -5.66±2.08, P<0.05) were significantly lower in patients with CA. Cox multivariate analyses demonstrated that RV-GRPS [hazard ratio (HR) =0.93, 95% CI: 0.88-0.98, P=0.007] and Mayo stage were (HR =3.11, 95% CI: 1.30-7.41, P=0.01) predictors of mortality in AL patients. CMR tissue tracking is a feasible and highly reproducible technique for the analysis of RV deformation and could aid in the early diagnosis of RV involvement in AL patients. RV-GRPS of RV strain and Mayo stage provides prognostic information about mortality in AL patients.

Speckle-tracking echocardiography combined with imaging mass spectrometry assesses region-dependent alterations

Left ventricular (LV) contraction is characterized by shortening and thickening of longitudinal and circumferential fibres. To date, it is poorly understood how LV deformation is altered in the pathogenesis of streptozotocin (STZ)-induced type 1 diabetes mellitus-associated diabetic cardiomyopathy and how this is associated with changes in cardiac structural composition. To gain further insights in these LV alterations, eight-week-old C57BL6/j mice were intraperitoneally injected with 50 mg/kg body weight STZ during 5 consecutive days. Six, 9, and 12 weeks (w) post injections, echocardiographic analysis was performed using a Vevo 3100 device coupled to a 30-MHz linear-frequency transducer. Speckle-tracking echocardiography (STE) demonstrated impaired global longitudinal peak strain (GLS) in STZ versus control mice at all time points. 9w STZ animals displayed an impaired global circumferential peak strain (GCS) versus 6w and 12w STZ mice. They further exhibited decreased myocardial deformation behaviour of the anterior and posterior base versus controls, which was paralleled with an elevated collagen I/III protein ratio. Additionally, hypothesis-free proteome analysis by imaging mass spectrometry (IMS) identified regional- and time-dependent changes of proteins affecting sarcomere mechanics between STZ and control mice. In conclusion, STZ-induced diabetic cardiomyopathy changes global cardiac deformation associated with alterations in cardiac sarcomere proteins.

Quantification of regional myocardial mean intracellular water lifetime: A nonhuman primate study in myocardial stress.

Heart failure with preserved ejection fraction (HFpEF) is typically associated with early metabolic remodeling. Noninvasive imaging biomarkers that reflect these changes will be crucial in determining responses to early drug interventions in these patients. Mean intracellular water lifetime (τi ) has been shown to be partially inversely related to Na, K-ATPase transporter activity and may thus provide insight into the metabolic status in HFpEF patients. Here, we aim to perform regional quantification of τi using dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) in the nonhuman primate (NHP) heart and evaluate its region-specific variations under conditions of myocardial stress in the context of perturbed myocardial function. Cardiac stress was induced in seven naïve cynomolgus macaques using a dobutamine stepwise infusion protocol. All animals underwent 3 T cardiac dual-bolus DCE and tagging MRI experiments. The shutter-speed model was employed to quantify regional τi from the DCE-MR images. Additionally, τi values were correlated with myocardial strains. During cardiac stress, there was a significant decrease in global τi (192.9 ± 76.3 ms vs 321.6 ± 70 ms at rest, P < 0.05) in the left ventricle, together with an increase in global peak circumferential strain (-15.4% ± 2.7% vs -10.1% ± 2.9% at rest, P < 0.05). Specifically, slice-level analysis further revealed that a greater significant decrease in mean τi was observed in the apical region (ΔτI = 182.4 ms) compared with the basal (Δτi = 113.2 ms) and midventricular regions (Δτi = 108.4 ms). Regional analysis revealed that there was a greater significant decrease in mean τi in the anterior (Δτi = 243.9 ms) and antero-lateral (Δτi = 177.2 ms) regions. In the inferior and infero-septal regions, although a decrease in τi was observed, it was not significant. Whole heart regional quantification of τi is feasible using DCE-MRI. τi is sensitive to regional changes in metabolic state during cardiac stress, and its value correlates with strain.

P5288Slice position vulnerability in the basal and apical parts for right ventricular circumferential strain measurement with feature tracking cardiac magnetic resonance

Abstract Background Strain is a more sensitive and precise parameter than ejection fraction (EF) for detection and characterization of subclinical left ventricular (LV) dysfunction and remodeling. Similar relationship is expected for right ventricle (RV); however RV functional parameters are less validated. Feature tracking strain analysis based on standard cardiac magnetic resonance (CMR) cine imaging is available for both ventricles. We experience a large slice-to-slice variation for RV global circumferential strain (GCS), possibly making the parameter vulnerable to minute position changes. Purpose To evaluate slice-to-slice differences in RV GCS for identification of the least variation region in a patient group without regional RV disease, in order to achieve a robust method for measurement. Hypothesis The slice-to-slice difference in peak GCS is lower in the mid-ventricular part of the RV than in the basal and apical parts. Methods 50 patients 6–72 months after pulmonary embolism without other major cardiopulmonary disease were included; mean age 60 years (range: 18–75 years); 68% men. Standard 2D cine CMR was obtained in longitudinal planes and in 10–12 consecutive 10 mm short axis planes for complete coverage of the RV. RV free wall and the inner contour of the septum were manually segmented on every end-diastolic and end-systolic slice from the pulmonary valve to the apex for feature tracking strain analysis. Peak RV GCS for every short axis slice and GCS difference (absolute percentage points) between adjacent slices were calculated. RV EF and peak RV GLS from the 4-chamber image were measured for correlation to RV GCS. Wilcoxon signed rank test and Pearson correlation were performed. Confidence intervals of means are based on 1000 bootstrap samples. Results RV EF was 46.6% (95% CI: 44.3; 48.8), RV peak GLS was −17.6% (95% CI: −18.6; −16.6). RV mid-ventricular GCS was −10.9% (95% CI: −12.0; −9.9). RV peak GCS slice-to-slice difference was 6.8 absolute percentage points (95% CI: 6.0; 7.6) in the basal part, 2.7 (95% CI: 2.4; 3.0) in the mid-ventricular part and 4.6 (95% CI: 3.9; 5.3) apically. Difference was significantly lower in mid-ventricular (p&lt;0.001) compared to both basal and apical. RV EF correlated to RV peak GLS (r: −0.397, p=0.004) and mid-ventricular peak GCS (r: −0.356, p=0.01) but not to basal or apical peak GCS. RV peak GLS correlated to basal and mid-ventricular peak GCS (r: 0.313, p=0.03 and r: 0.301, p=0.03 respectively) but not to apical peak GCS. Figure 1 shows slice-to-slice difference (expressed in absolute percentage points) in right ventricular peak GCS. Conclusion Slice-to-slice difference in RV peak GCS was significantly lower in the mid-ventricular region. Large differences in the basal and apical parts indicate that measurements largely depend on slice positioning.

Cardiac magnetic resonance feature tracking for quantifying right ventricular deformation in type 2 diabetes mellitus patients

To determine the feasibility of deformation analysis in the right ventricle (RV) using cardiovascular magnetic resonance myocardial feature tracking (CMR-FT) in type 2 diabetes mellitus (T2DM) patients. We enrolled 104 T2DM patients, including 14 with impaired right ventricular ejection fraction (RVEF) and 90 with preserved RVEF, and 26 healthy controls in this prospective study. CMR was used to determine RV feature-tracking parameters. RV strain parameters were compared among the controls, patients with preserved and reduced RVEF. Binary logistic regression was used to predict RV dysfunction. Receiver operating characteristic analysis was used to assess the diagnostic accuracy. The agreement was tested by Bland–Altman analysis. Compared with controls, longitudinal and circumferential global peak strain (PS) and PS at mid-ventricular, apical slices were significantly decreased in T2DM patients with or without reduced RVEF (p < 0.05). Within the T2DM patients, the global longitudinal PS (GLPS) and the longitudinal PS at mid-ventricular segments were significantly reduced in the reduced RVEF group than in preserved RVEF groups (p < 0.05). GLPS was an independent predictor of RV dysfunction (odds ratio: 1.246, 95% CI: 1.037–1.496; p = 0.019). The GLPS demonstrated greater diagnostic accuracy (area under curve: 0.716) to predict RV dysfunction. On Bland-Altman analysis, global circumferential PS and GLPS had the best intra- and inter-observer agreement, respectively. In T2DM patients, CMR-FT could quantify RV deformation and identify subclinical RV dysfunction in those with normal RVEF. Further, RV strain parameters are potential predictors for RV dysfunction in T2DM patients.

The early diagnosis of MYH7 gene mutation carriers of hypertrophic cardiomyopathy using multi-parameter analysis model by conventional two-dimensional echocardiography and three-dimensional speckle tracking imaging

Objective To create multi-parameter analysis model by conventional two-dimensional echorcardiography(2DE) and three-dimensional speckle tracking imaging(3D-STI) in order to improve the early diagnosis in MYH7G+ P- mutation carriers of familiar hypertrophic cardiomyopathy(HCM). Methods Twenty-eight MYH7 mutation carriers without left ventricular hypertrophy (MYH7G+ P-) were enrolled as the research group, while 27 MYBPC3 mutation carriers without left ventricular hypertrophy (MYBPC3G+ P-) were selected as the control group. The clinical data, conventional 2DE and tissue Doppler imaging(TDI) parameters of the two groups were acquired, including the maximum of the thickness of interventricular septum(IVS) and left ventricular posterior ventricular wall thickness(LVPWT) in end of diastole, mitral flow E and A velocities, E peak deceleration time(EDT), atrioventricular filling time, mitral annulus velocity of interventricular septum IVS-e′ and lateral wall L-e′, interventricular septum IVS-a′ and lateral wall L-a′ peak in diastole, calculate mean value e′ and a′, and calculate E/ e′, E/A, left atrial volume index(LAVI), left ventricular mass index(LVMI), left ventricular ejection fraction(LVEF) and isovolumic relaxation time(IVRT), isovolumic contraction time(IVCT). The global longitudinal peak strain(GLS), global radial peak strain(GRS), global circumferential peak strain(GCS) and global area peak strain(GAS) were acquired by 3D-STI. All parameters were compared between research group and control group. Results Compared with the control group, research group significantly increased in LAVI, maximum IVS and LVPWT, LVMI and GAS(P 0.05). For single parameter, the area under ROC curve(AUC) were successively LVPWT>LAVI>IVS>LVMI>GAS(0.772, 0.738, 0.733, 0.719, 0.714, respectively). AUC of multi-parameters was 0.912, the sensitivity and specificity were 85.2% and 96.3%, respectively. Conclusions Multi-parameter analysis model by conventional 2DE and 3D-STI can significantly improve the recognition efficiency of early diagnosis MYH7G+ P- of familiar HCM. With further, maximum LVPWT is an independent predictor of distinction MYH7G+ P- and MYBPC3G+ P-. Key words: Echocardiography; Cardiomyopathy, hypertrophic; MYBPC3; MYH7; Speckle tacking imaging, three-dimensional

Combined myocardial deformation to predict cardiac resynchronization therapy response in nonischemic cardiomyopathy.

20-30% of patients do not benefit from cardiac resynchronization therapy (CRT) when the established selection criteria were applied. We hypothesized that a combined assessment of mechanical dyssynchrony, myocardial deformation, and diastolic function would identify patients who would benefit most from CRT. In 36 CRT patients, clinical evaluation and echocardiography were performed before and after CRT. Patients were classified into three subgroups according to their amount of response: echocardiographic responders, clinical responders, and nonresponders. Radial dyssynchrony and left ventricular (LV) global longitudinal, radial, and circumferential peak strain was assessed by speckle-tracking image. Diastolic function was quantified by conventional echocardiography. In addition to left bundle branch block, nonspecific intraventricular conduction disturbance with intraventricular dyssynchrony could also improve LV remodeling. Echocardiographic responders had better global longitudinal strain, global circumferential peak strain, and global radial strain at baseline which significantly increased at 12-month follow-up. An improvement in estimates of LV filling pressure and a decrease in mitral regurgitation and left atrial dimensions were observed only in echocardiographic responders to CRT. Patients with clinical but without echocardiographic response showed a significant improvement in atrioventricular (AV) synchrony and a nonsignificant improvement in other parameters. The nonresponder group did not improve the AV and intraventricular dyssynchrony. CRT could not improve restrictive filling pattern with normal filling time. Overall, those patients with AV and intraventricular dyssynchrony and those with best contractile function and short diastolic filling time of restrictive filling pattern at baseline demonstrated the greatest benefit from CRT. Mechanical dyssynchrony, contractile function, and filling pattern are important determinants of the benefits in CRT.

Evaluation of left ventricular strain in patients with dilated cardiomyopathy.

ObjectiveDilated cardiomyopathy (DCM) can cause structural and functional changes in the left ventricle (LV). In this study, we evaluated whether cardiac magnetic resonance tissue-tracking (MR-TT) can be applied to the detection of LV abnormalities in patients with DCM.MethodsWe used MR-TT to analyze the global peak radial strain (GPRS), global peak circumferential strain (GPCS), and global peak longitudinal strain (GPLS) in every segment of the LV in 23 patients with DCM and 25 controls. The LV ejection fraction was also measured as a function indicator.ResultsCompared with the controls, the GPRS, GPCS, and GPLS were significantly reduced in patients with DCM, indicating global LV function impairment in all directions. We also identified a significant linear correlation between the GPRS, GPCS, and GPLS and the LV ejection fraction, indicating that LV function relies on coordinated wall motion from all directions. Moreover, we found that patients with DCM had a significantly reduced magnitude of the PRS, PCS, and PLS in most segments at different levels, indicating impaired myocardial function in most LV regions.ConclusionsOur results demonstrate that LV myocardial strain in patients with DCM can be sensitively detected by MR-TT (not only the global LV function changes but also the segmental strain), which can help to identify the injured segment at an early stage and guide clinical treatment.

Assessment of left ventricular deformation in patients with Ebstein’s anomaly by cardiac magnetic resonance tissue tracking

PurposeThe aim of this study was to clarify the feasibility of myocardial strain using cardiovascular magnetic resonance (CMR) for the evaluation of left ventricular (LV) deformation in patients with Ebstein’s anomaly (EA). Materials and methodsWe recruited 32 patients with EA and 30 controls for CMR examination and measured LV function, dimension and tissue tracking parameters (the global and regional radial, circumferential and longitudinal peak strain), together with the right ventricle (RV) dimension. LV strain parameters were compared among the controls, patients with preserved LV ejection fraction (LVEF; ≥55%), and patients with reduced LVEF (<55%). Pearson’s correlation was used to evaluate relationships between tissue tracking parameters with the RVEDD/LVEDD index and LVEF. An ROC analysis was also performed to determine whether the cut-off values for PS could be used to differentiate LV dysfunction between patients with EA and controls. The intraclass correlation coefficient (ICC) was used to assess the inter- and intra-observer variability. ResultsThe global strain parameters all decreased significantly in the EA group compared with the control group (all P<0.05). Furthermore, the global radial and circumferential peak strain (PS) were obviously even lower in the reduced LVEF group than the strain measured in preserved LVEF groups (28.64% vs. 37.39%, p<0.05; and −8.20% vs. −17.89%; p<0.05; respectively). The regional strain abnormalities in EA patients were mainly involved in basal and middle segments. The results also demonstrated a significant correlation between the ratio of the RV end-diastolic dimension to the LV end-diastolic dimension (RVEDD/LVEDD index) with the global circumferential PS (r=0.508) and the longitudinal PS (r=0.474), as well as a good correlation between radial PS and LVEF (r=0.465). The ICCs for intra- and inter-observer variability were 0.797–0.904 and 0.701–0.896. ConclusionsLV strain serves an earlier and more comprehensive measurement of LV dysfunction than LVEF in EA, which could potentially be included as a supplementary diagnostic procedure in the evaluation of EA.

Novel cardiac nuclear magnetic resonance method for noninvasive assessment of myocardial fibrosis in hemodialysis patients

Left ventricular hypertrophy and myocardial fibrosis frequently occur in patients with end-stage renal disease receiving hemodialysis therapy and are associated with poor prognosis. Native T1 mapping is a novel cardiac magnetic resonance imaging technique that measures native myocardial T1 relaxation, a surrogate of myocardial fibrosis. Here we compared global and segmental native myocardial T1 time and global longitudinal, circumferential and segmental strain, and cardiac function of 35 hemodialysis patients and 22 control individuals. The median native global T1 time was significantly higher in the hemodialysis than the control group (1270 vs. 1085 ms), with the septal regions of hemodialysis patients having significantly higher median T1 times than nonseptal regions (1293 vs. 1252 ms). The mean peak global circumferential strain and global longitudinal strain were both significantly reduced in hemodialysis patients compared with controls (-18.3 vs. -21.7 and -16.1 vs. -20.4, respectively). Systolic strain was also significantly reduced in the septum compared with the nonseptal myocardium in hemodialysis patients (-16.2 vs. -21.9) but not in control subjects. Global circumferential strain and longitudinal strain significantly correlated with global native T1 values (r= 0.41 and 0.55, respectively), and the septal native T1significantly correlated with the septal systolic strain (r= 0.46). Thus, myocardial fibrosis may be assessed noninvasively with native T1 mapping; the interventricular septum appears to be particularly prone to the development of fibrosis in hemodialysis patients.

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

This study assessed the use of 3-dimensional (3D) speckle-tracking echocardiography for noninvasive monitoring and diagnosis of acute rejection in heart transplant recipients. 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. 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%. 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.

Left and right ventricular dyssynchrony and strains from cardiovascular magnetic resonance feature tracking do not predict deterioration of ventricular function in patients with repaired tetralogy of Fallot.

BackgroundPatients with repaired tetralogy of Fallot (rTOF) suffer from progressive ventricular dysfunction decades after their surgical repair. We hypothesized that measures of ventricular strain and dyssynchrony would predict deterioration of ventricular function in patients with rTOF.MethodsA database search identified all patients at a single institution with rTOF who underwent cardiovascular magnetic resonance (CMR) at least twice, >6 months apart, without intervening surgical or catheter procedures. Seven primary predictors were derived from the first CMR using a custom feature tracking algorithm: left (LV), right (RV) and inter-ventricular dyssynchrony, LV and RV peak global circumferential strains, and LV and RV peak global longitudinal strains. Three outcomes were defined, whose changes were assessed over time: RV end-diastolic volume, and RV and LV ejection fraction. Multivariate linear mixed models were fit to investigate relationships of outcomes to predictors and ten potential baseline confounders.ResultsOne hundred fifty-three patients with rTOF (23 ± 14 years, 50 % male) were included. The mean follow-up duration between the first and last CMR was 2.9 ± 1.3 years. After adjustment for confounders, none of the 7 primary predictors were significantly associated with change over time in the 3 outcome variables. Only 1–17 % of the variability in the change over time in the outcome variables was explained by the baseline predictors and potential confounders.ConclusionsIn patients with repaired tetralogy of Fallot, ventricular dyssynchrony and global strain derived from cine CMR were not significantly related to changes in ventricular size and function over time. The ability to predict deterioration in ventricular function in patients with rTOF using current methods is limited.Electronic supplementary materialThe online version of this article (doi:10.1186/s12968-016-0268-8) contains supplementary material, which is available to authorized users.

Abstract 11125: Increasing Stimulus Strength of Coronary Sinus Pacing Improved Left Ventricular Mechanical Dyssynchrony and Contractile Function in Patients With Reduced Ejection Fraction

Introduction: Increasing stimulus strength of left ventricular (LV) coronary sinus pacing decreases QRS duration and inter-ventricular conduction time. Hypothesis: Increasing stimulus strength of LV coronary sinus pacing improves LV mechanical dyssynchrony and myocardial function. Methods: We studied 36 patients with 6±4 months after cardiac resynchronization therapy (LV ejection fraction: 39±11%). The LV pacing lead was positioned in lateral or posterolateral coronary sinus vein. We measured standard deviation (SD) of time to negative peak circumferential strain (time-CircS) in 6 segments and peak global circumferential strain value (CircS) using two-dimensional speckle-tracking echocardiography to evaluate LV mechanical dyssynchrony and myocardial contractile function, respectively. Low (1.3±0.6V), clinical (2.6±1.0V), and high (7.3±1.1V) voltage conditions of LV coronary sinus pacing were performed under right ventricular pacing-off. Results: SD of time-CircS and global CircS under high voltage LV coronary sinus pacing was significantly better than those under low and clinical voltage (78±38 vs. 90±48 and 92±43msec, p=0.014 and 0.016; 5.7±3.4 vs. 5.4±3.3 and 5.4±3.4%, p=0.007 and 0.003). Moreover, global CircS significantly correlated with SD of time-CircS (r= -0.54, p&lt;0.001, n=108). Conclusions: Increasing stimulus strength of LV coronary sinus pacing improved LV mechanical dyssynchrony and LV contractile function, leading clinical implication for better management of heart failure patients with cardiac resynchronization therapy.

Comparison of strain measurement from multimodality tissue tracking with strain-encoding MRI and harmonic phase MRI in pulmonary hypertension

BackgroundPixel-based multimodality tissue tracking (MTT) is a new noninvasive method for the quantification of cardiac deformation from cine image of MRI. The aim of this study is to validate bi-ventricular strain measurement by MTT compared to strain-encoding (SENC) MRI and harmonic phase (HARP) MRI in pulmonary hypertension (PH) patients. MethodsIn 45 subjects (30 PH patients and 15 normal subjects), RV and LV peak global longitudinal strains (Ell) were measured from long axis 4 chamber view using MTT. LV peak global circumferential strains (Ecc) by MTT were measured from short axis. For validation, RV and LV Ell by MTT were compared to measures by SENC-MRI from short axis, and LV Ecc by MTT was compared to measures by short axis tagged MRI analysis (HARP). Reproducibility of MTT was also determined. ResultsMTT quantified RV Ell correlated closely to those of SENC (r=0.72, p<0.001), with good limits of agreement. LV Ell quantified by MTT showed moderate correlation with SENC (r=0.57, p=0.001), and LV Ecc by MTT also showed moderate correlation with HARP (−16.9±4.1 vs −14.3±3.5, p<0.001 for all, r=0.60, p<0.001). RV Ell negatively correlated with RVEF (r=−0.53, p=0.001) and also positively correlated with mean PAP in PH patients (r=0.60, p=0.001). Strain measurement by MTT showed high reproducibility. ConclusionsWe demonstrate that MTT is a reproducible tool for quantification of cardiac deformation using cine images in PH patients. Hence, it could serve as a new rapid and comprehensive technique for clinical assessment of regional cardiac function.