Chinami Miyazaki

Left Ventricular Torsion by Two-Dimensional Speckle Tracking Echocardiography in Patients with Diastolic Dysfunction and Normal Ejection Fraction

BACKGROUND Left ventricular torsion (LVtor) and subsequent untwisting play an important role in diastolic filling. There is, however, limited information about how LVtor and untwisting are related to the severity of diastolic dysfunction. The aim of this study was to assess LVtor and untwisting in the progressive severity of diastolic dysfunction. METHODS We studied 148 subjects (116 with diastolic dysfunction, 32 healthy controls). Apical and basal short-axis rotations were measured by 2-dimensional speckle tracking echocardiography. LVtor was defined as the instantaneous net difference of the basal and apical rotation. Patients were divided into 3 groups according to diastolic dysfunction grade and their underlying disease, such as hypertension, hypertrophic cardiomyopathy, and amyloidosis. RESULTS Age, gender, and ejection fraction were similar in the 3 groups and control. Mitral annulus early diastolic velocity was reduced by design in all 3 groups. Peak LVtor was significantly greater in mild diastolic dysfunction (n = 45; 29.7 +/- 9.0 degrees) compared with control (n = 32: 15.6 +/- 4.0 degrees) and then normalized in moderate (n = 49; 19.3 +/- 4.8 degrees) and severe diastolic dysfunction (n = 22; 17.3 +/- 9.3 degrees). The twisting and untwisting rates were significantly higher in mild diastolic dysfunction group. CONCLUSION Systolic torsion and diastolic untwisting are significantly increased in patients with mild diastolic dysfunction. In patients with advanced diastolic dysfunction with increased filling pressure, they are normalized or reduced. Whether increased LVtor is a compensatory mechanism for reduced myocardial relaxation or a consequence of reduced filling in the early stage of diastolic dysfunction requires further investigation. Analysis of LVtor with speckle tracking echocardiography should be further explored to elucidate the role of torsion in patients with diastolic dysfunction.

Comparison of Echocardiographic Dyssynchrony Assessment by Tissue Velocity and Strain Imaging in Subjects With or Without Systolic Dysfunction and With or Without Left Bundle-Branch Block

Background— Several echocardiographic dyssynchrony indexes have been proposed to identify responders to cardiac resynchronization therapy using tissue velocity and strain. The present study aimed to compare tissue velocity–derived and strain-derived dyssynchrony indexes in patients with or without systolic dysfunction and left bundle-branch block. Methods and Results— Tissue Doppler imaging was performed in 120 subjects divided into 4 groups: group 1 (n=40), normal subjects; group 2 (n=20), normal left ventricular ejection fraction and left bundle-branch block; group 3 (n=20), left ventricular ejection fraction <35% and normal conduction; and group 4 (n=40), left ventricular ejection fraction <35% and left bundle-branch block. Dyssynchrony indexes based on time to peak tissue velocity (septal-lateral delay, anteroseptal-posterior delay, and SD in time to peak systolic velocity in the 12 left ventricular segments) and strain (SD of time to peak strain in 12 segments) were measured. The SD in time to peak systolic velocity in the 12 left ventricular segments was greater in group 4 (54 ms; 25th and 75th percentiles, 46 to 64 ms) than group 1 (44 ms; 25th and 75th percentiles, 28 to 53 ms; P=0.006), but there was a considerable overlap of all tissue velocity–derived indexes among 4 groups, with 40% to 68% of group 1 having values proposed for predicting the responders of cardiac resynchronization therapy. The SD of time to peak strain in 12 segments distinguished these groups with much less overlap (P<0.01 for all pairwise comparisons). Conclusions— A substantial proportion of normal subjects have tissue velocity–derived dyssynchrony indexes higher than the cutoff value proposed for predicting beneficial effect of cardiac resynchronization therapy. Strain-derived timing index appears to be more specific for dyssynchrony in patients with systolic dysfunction and left bundle-branch block. Identifying an optimal tissue velocity– or strain-derived dyssynchrony index requires a large prospective clinical trial.

Patient Selection and Echocardiographic Assessment of Dyssynchrony in Cardiac Resynchronization Therapy

Appropriate cardiac resynchronization therapy (CRT) enhances quality of life and improves survival in patients with refractory heart failure due to systolic dysfunction and mechanical dyssynchrony. On the assumption that the main therapeutic mechanism of CRT is the correction of dyssynchronous myocardial contraction, imaging-based measures of dyssynchrony have been intensely investigated with the aim of predicting response to therapy. Numerous echocardiographic dyssynchrony parameters have been proposed, but no large prospective trial have been published to prove the clinical utility of any of these indexes. Moreover, the methodology to derive the proposed dyssynchrony indexes has not been standardized. Therefore, the purpose of this article is to critically review the current status of proposed dyssynchrony indexes by echocardiography for patient selection and to recommend future investigations in this area. The adverse effects of dyssychronous activation1 and the ability to correct these abnormalities with biventricular stimulation2 were described long ago, but the potential therapeutic application was not realized until an unprecedented study in 1990 reported recovery from intractable heart failure in 16 patients implanted with conventional dual-chamber pacemakers programmed to a short atrioventricular (AV) delay.3 Although these results could not be reproduced in prospective studies4,5 and improvements could only be demonstrated short-term in highly selected patients,6 the race to find a pacing therapy for heart failure had begun. On the hypothesis that the disappointing results of dual-chamber pacing in prospective studies were due to cancelling or overcoming the beneficial effects of AV synchronisation by the adverse effect of RV pacing-induced dyssynchrony,7,8 Cazeau and colleagues proposed a 4-chamber pacing mode and reported the first successful permanent implant in 1994.9 Early randomized controlled trials confirmed short-term improvements in functional capacity and quality of life for patients.10–13 However it was the Comparison of Medical Therapy, Pacing, and Defibrillation in …

Evidence of Impaired Left Ventricular Systolic Function by Doppler Myocardial Imaging in Patients With Systemic Amyloidosis and No Evidence of Cardiac Involvement by Standard Two-Dimensional and Doppler Echocardiography

We examined the potential role of Doppler myocardial imaging for early detection of systolic dysfunction in patients with systemic amyloidosis (AL) but without evidence of cardiac involvement by standard echocardiography. We identified 42 patients without 2-dimensional echocardiographic or Doppler evidence of cardiac involvement. These patients had normal ventricular wall thickness and normal velocity of the medial mitral annulus. Myocardial images were obtained in these patients and in 32 age- and gender-matched healthy controls. Peak longitudinal systolic tissue velocity (sTVI), systolic strain rate (sSR), and systolic strain (sS) were determined for 16 left ventricular segments. Radial and circumferential sSR and sS were also measured. Compared with controls in this group of patients with AL, peak longitudinal sSR (-1.0 +/- 0.2 vs -1.4 +/- 0.2, p <0.001) and peak longitudinal sS (-15.6 +/- 3.3 vs -22.5 +/- 2.0 p <0.001) were significantly decreased. In conclusion, the mean sS from all 6 basal segments, or from all 16 left ventricular segments differentiated patients with AL with normal echocardiography from controls, with similar accuracy for the mean sSR from the 6 basal segments. This distinction was not apparent from peak longitudinal sTVI or from radial or circumferential sSI or sSR.

Independent Predictors of Survival in Primary Systemic (AL) Amyloidosis, Including Cardiac Biomarkers and Left Ventricular Strain Imaging: An Observational Cohort Study

BACKGROUND The prognostic value of Doppler myocardial imaging, including myocardial velocity imaging, strain, and strain rate imaging, in patients with primary (AL) amyloidosis is uncertain. The aim of this longitudinal study was to identify independent predictors of survival, comparing clinical data, hematologic and cardiac biomarkers, and standard echocardiographic and Doppler myocardial imaging measures in a cohort of patients with AL amyloidosis. METHODS A total of 249 consecutive patients with AL amyloidosis were prospectively enrolled. The primary end point was all-cause mortality, and during a median follow-up period of 18 months, 75 patients (30%) died. Clinical and electrocardiographic data, biomarkers (brain natriuretic peptide and cardiac troponin T) and standard echocardiographic and longitudinal systolic and diastolic Doppler myocardial imaging measurements for 16 left ventricular segments were tested as potential independent predictors of survival. RESULTS Age (hazard ratio [HR], 1.03; P = .03), New York Heart Association class III or IV (HR, 2.47; P = .01), the presence of pleural effusion (HR, 1.79; P = .08), brain natriuretic peptide level (HR, 1.29; P = .01), ejection time (HR, 0.99; P = .13), and peak longitudinal systolic strain of the basal anteroseptal segment (HR, 1.05; P = .02) were independent predictors in the final model. CONCLUSIONS Multivariate survival analysis identified independent predictors of clinical outcome in patients with AL amyloidosis: New York Heart Association class III or IV, presence of pleural effusion, brain natriuretic peptide level > 493 pg/mL, ejection time < 273 ms, and peak longitudinal systolic basal anteroseptal strain less negative than or equal to -7.5% defined a high-risk group of patients.

Dyssynchrony Indices To Predict Response to Cardiac Resynchronization Therapy A Comprehensive Prospective Single-Center Study

Background—Whether mechanical dyssynchrony indices predict reverse remodeling (RR) or clinical response to cardiac resynchronization therapy (CRT) remains controversial. This prospective study evaluated whether echocardiographic dyssynchrony indices predict RR or clinical response after CRT. Methods and Results—Of 184 patients with heart failure with anticipated CRT who were prospectively enrolled, 131 with wide QRS and left ventricular ejection fraction <35% had 6-month follow-up after CRT implantation. Fourteen dyssynchrony indices (feasibility) by M-mode (94%), tissue velocity (96%), tissue Doppler strain (92%), 2D speckle strain (65% to 86%), 3D echocardiography (79%), and timing intervals (98%) were evaluated. RR (end-systolic volume reduction ≥15%) occurred in 55% and more frequently in patients without (71%) than in patients with (42%) ischemic cardiomyopathy (P=0.002). Overall, only M-mode, tissue Doppler strain, and total isovolumic time had a receiver operating characteristic area under the curve (AUC) greater than the line of no information, but none of these were strongly predictive of RR (AUC, 0.63 to 0.71). In nonischemic cardiomyopathy, no dyssynchrony index predicted RR. In ischemic cardiomyopathy, M-mode (AUC, 0.67), tissue Doppler strain (AUC, 0.79), and isovolumic time (AUC, 0.76) -derived indices predicted RR (P<0.05 for all), although the incremental value was modest. No indices predicted clinical response assessed by Minnesota Living with Heart Failure Questionnaire, 6-minute walk distance, and peak oxygen consumption. Conclusions—These findings are consistent with the Predictors of Response to CRT study and do not support use of these dyssynchrony indices to guide use of CRT.

Assessment of Coronary Flow Velocity With Transthoracic Doppler Echocardiography During Dobutamine Stress Echocardiography

OBJECTIVES The purpose of this study was to evaluate the feasibility of measuring coronary flow velocity (CFV) by transthoracic Doppler echocardiography (TTDE) in the left anterior descending coronary artery (LAD) during contrast-enhanced dobutamine stress echocardiography (DSE). We also assessed the value of TTDE for detecting stress-induced myocardial ischemia in the LAD territory. BACKGROUND Noninvasive assessment of both CFV and wall motion during DSE would enhance the diagnostic accuracy of DSE. METHODS One hundred forty-four consecutive patients underwent CFV recording in the distal LAD by TTDE during contrast-enhanced DSE. Regional wall motion score index (WMSI) in the LAD territory and CFV ratio at peak stress (CFV ratio peak), defined as a ratio of CFV at peak stress to basal CFV, were obtained. RESULTS Coronary flow velocity was successfully recorded in 129 patients (90%) at baseline and during dobutamine infusion. Mean value of CFV ratio peak was 2.39 +/- 0.83 (range: 0.84 to 4.40). There was good correlation between WMSI at peak stress and CFV ratio peak (r = 0.62, p < 0.001). Coronary flow velocity ratio peak was significantly lower in patients who developed stress-induced wall motion abnormality (WMA) in the LAD territory than it was in those patients without WMA (1.51 +/- 0.51 vs. 2.76 +/- 0.65, p < 0.001). A CFV ratio peak <2.1 had a sensitivity of 92% and a specificity of 86% for detecting the presence of stress-induced WMA. CONCLUSIONS Assessment of CFV in the distal LAD during DSE is feasible in the majority of cases and provides a CFV ratio for detecting stress-induced myocardial ischemia in the LAD territory.

Echocardiographic Parameters of Mechanical Synchrony in Healthy Individuals

Definition and validation of the ranges of normal values and agreement among echocardiographic measures of mechanical synchrony in healthy subjects are mostly lacking. The aims of this study were (1) to assess the ranges of normal values for 5 tissue Doppler imaging parameters, real-time 3-dimensional echocardiographic measures, and speckle-tracking measures of mechanical synchrony; (2) to evaluate interinstitutional variability; (3) to compare the ranges of normal values with those reported in previous research; and (4) to analyze the agreement among all parameters in the same healthy subject. Time to peak systolic velocity (Ts), the delay between Ts at the basal septal and lateral segments, peak velocity difference, strain derived by tissue Doppler imaging, Ts derived by tissue synchronization imaging, systolic synchrony index (SSI) derived by real-time 3-dimensional echocardiography, and longitudinal and radial strain derived by speckle tracking were prospectively collected and analyzed at 2 different institutions in 160 consecutive healthy subjects. The ranges of normal values, expressed as means +/- 2 SDs, were 30.32 +/- 29.36 ms for the SD of Ts, 15.51 +/- 99.88 ms for septal-lateral delay, 60.75 +/- 81.62 ms for peak velocity difference, 33.07 +/- 29.96 ms for tissue synchronization imaging, 34.16 +/- 23.26 ms for the SD of strain, 2.74 +/- 2.16% for SSI, 28.91 +/- 23.02 ms for the SD of longitudinal strain, and 10.4 +/- 6.31 ms for radial strain. There was large interinstitutional variability for all parameters. Three-dimensional SSI and radial strain were within the published upper range limit for healthy subjects. Ninety percent of healthy subjects were consistently classified to be synchronous by 1 parameter. With a composite index, more subjects than expected showed dyssynchrony (10% vs 2.5%). In conclusion, 3-dimensional SSI and radial strain were the most reproducible parameters and consistently discriminated normal healthy subjects from the cardiac resynchronization therapy volume responders.

Dyssynchrony Indices To Predict Response to Cardiac Resynchronization Therapy

Background—Whether mechanical dyssynchrony indices predict reverse remodeling (RR) or clinical response to cardiac resynchronization therapy (CRT) remains controversial. This prospective study evaluated whether echocardiographic dyssynchrony indices predict RR or clinical response after CRT. Methods and Results—Of 184 patients with heart failure with anticipated CRT who were prospectively enrolled, 131 with wide QRS and left ventricular ejection fraction <35% had 6-month follow-up after CRT implantation. Fourteen dyssynchrony indices (feasibility) by M-mode (94%), tissue velocity (96%), tissue Doppler strain (92%), 2D speckle strain (65% to 86%), 3D echocardiography (79%), and timing intervals (98%) were evaluated. RR (end-systolic volume reduction ≥15%) occurred in 55% and more frequently in patients without (71%) than in patients with (42%) ischemic cardiomyopathy (P=0.002). Overall, only M-mode, tissue Doppler strain, and total isovolumic time had a receiver operating characteristic area under the curve (AUC) greater than the line of no information, but none of these were strongly predictive of RR (AUC, 0.63 to 0.71). In nonischemic cardiomyopathy, no dyssynchrony index predicted RR. In ischemic cardiomyopathy, M-mode (AUC, 0.67), tissue Doppler strain (AUC, 0.79), and isovolumic time (AUC, 0.76) -derived indices predicted RR (P<0.05 for all), although the incremental value was modest. No indices predicted clinical response assessed by Minnesota Living with Heart Failure Questionnaire, 6-minute walk distance, and peak oxygen consumption. Conclusions—These findings are consistent with the Predictors of Response to CRT study and do not support use of these dyssynchrony indices to guide use of CRT.

Cardiac Sympathetic Reserve and Response to Cardiac Resynchronization Therapy

Background— The objective of the present study was to investigate the effect of cardiac resynchronization therapy (CRT) on cardiac autonomic function. Methods and Results— This prospective study included 45 consecutive patients with heart failure who received CRT devices with defibrillator and 20 age-matched, healthy control subjects. At baseline and 3 months and 6 months after CRT, we assessed New York Heart Association (NYHA) class, 6-minute walk distance, plasma sympathetic biomarker nerve growth factor, echocardiography, heart rate variability and cardiac presynaptic sympathetic function determined by iodine 123 metaiodobenzylguanidine scintigraphy. After CRT, NYHA class improved by 1 class (P<0.001), and left ventricular ejection fraction increased by 8% (P<0.001). Along with improvement in the standard deviation of all normal-to-normal R-R intervals (85.63±31.66 ms versus 114.79±38.99 ms; P=0.004) and the standard deviation of the averaged normal-to-normal R-R intervals (82.62±23.03 ms versus 100.50±34.87 ms; P=0.004), the delayed heart/mediastinum (H/M) ratio increased (1.82 [0.58] versus 1.97 [0.59]; P=0.03), whereas the mean (SD) H/M washout rate was reduced (48% [19%] versus 37% [22%]; P=0.01). Twenty-two of 45 study patients responded to CRT, with a reduction of left ventricular end-systolic volume index >15%. Compared with nonresponders, responders had a higher delayed H/M ratio (2.11 versus 1.48; P=0.003) and lower H/M washout rate (37% versus 62%; P=0.003) at baseline. Conclusions— CRT improved sympathetic function. Cardiac sympathetic reserve may be a marker for the reversibility of failing myocardial function.