Evaluation of biventricular longitudinal myocardial function in normal fetuses at different gestational ages using ultrasonic velocity vector imaging.

Objective: This study aimed to evaluate biventricular myocardial function and biventricular longitudinal global myocardial function of fetuses at different gestational weeks using ultrasonic velocity vector imaging. Methods: A total of 127 pregnant women were enrolled and divided into five groups according to the gestational age of their fetuses. The velocity, strain, and strain rate of the left and right ventricles were measured, and these biventricular parameters were compared between the groups. The global parameters of the biventricular myocardium were also compared. Results: A pairwise comparison revealed that the differences in biventricular velocity and strain rate between groups in adjacent gestational weeks were not statistically significant (P > 0.05), but velocity increased with gestational age. A comparison of fetal longitudinal global myocardial parameters revealed that the global velocity, strain, and strain rate of the right ventricle were higher than those of the left ventricle, and the differences were statistically significant (P < 0.05) in all groups. Conclusion: The peak velocities of the fetal left and right ventricles increased with gestational age, but the global strain and strain rate did not, suggesting that fetal myocardial function is mature and constant in the middle and late stages of pregnancy and can more reliably reflect myocardial deformation. The peak systolic velocity, global strain, and peak strain rate of the right ventricle were higher than those of the left ventricle, suggesting that the right ventricle dominates longitudinal systolic movement from the second trimester of pregnancy.

Importance of chronotropic response and left ventricular long-axis function for exercise performance in patients with heart failure and preserved ejection fraction.

BACKGROUND: We evaluated the relationship between the degree of chronotropic incompetence and left ventricular (LV) impairment during exercise with severity of exercise intolerance in patients with heart failure and preserved ejection fraction (HFPEF). METHODS: All patients underwent exercise echocardiography during bicycle Ergometer exercise with the acquisition of long-axis tissue Doppler imaging (TDI). Peak heart rates during exercise were also recorded and the percentages of maximal age-predicted heart rate (%MPHR) and heart rate reserve (%HRR) were calculated thereby. Besides, cardiopulmonary exercise testing was performed with peak oxygen consumption (VO2) measuring averaged at the highest 30-second during exercise. RESULTS: Forty HFPEF patients (aged 65±9 years; 75% male) were divided into two groups according to the median of peak VO2: patients with peak VO2<16.5 and ≥16.5 ml/kg/min, respectively. Patients with lower peak VO2 had decreased peak heart rates, %MPHR, %HRR, stroke volume and cardiac indices (LVSI and LVCI) than those with higher peak VO2 (all p<0.05). The LV long-axis functions (TDI Sm, Em, s' and e') were reduced in patients with lower peak VO2 (all p<0.05). Moreover, peak VO2 correlated with the following parameters: peak heart rates, %MPHR, %HRR, LVSI, LVCI, TDI Sm, Em, s' and e'(all p<0.05). CONCLUSIONS: The degree of blunted chronotropic response and impaired LV long-axis function were more profound in HFPEF patients with poor exercise performance.

Left ventricular long-axis performance during exercise is an important prognosticator in patients with heart failure and preserved ejection fraction.

BACKGROUND: Although many prognostic variables have been reported, the risk stratification of patients with heart failure and preserved ejection fraction (HFPEF) has long been controversial due to considerable discordance. Ergometry stress echocardiography may provide a more clinical relevant evaluation in HFPEF. We aimed at evaluating the prognostic value of echocardiographic parameters during exercise in HFPEF patients. METHODS: Comprehensive echocardiographic examination with symptom-limited exercise testing on a semi-recumbent and tilting bicycle Ergometer (Lode BV, Groningen, the Netherlands) was performed on 80 consecutive HFPEF patients (aged 66±8years; 64% male). The exercise images for two-dimensional (2D) speckle tracking analysis were acquired with heart rate of 90-100bpm, while exercise images for tissue Doppler imaging (TDI) and M-mode echocardiography were stored with attainment of >85% of maximal age-predicted heart rate. All patients were followed up for 3years after stress echocardiography for all-cause mortality and/or heart failure (HF) hospitalization. RESULTS: During the follow-up, 43 (54%) patients reached the combined end point: 5 (6%) patients died, and another 38 (48%) patients experienced HF hospitalizations. Univariate predictors were: decreased resting left atrial ejection fraction (LAEF), lower peak heart rate, elevated E/e' ratio, reduced TDI myocardial velocities, and impaired 2D global longitudinal strain (GLS) during exercise. Only impaired GLS (hazard ratio [HR] 0.79, 95% confidence interval [CI] 0.67 to 0.91) remained independent after multivariate analysis (p=0.008). CONCLUSIONS: More than half of the HFPEF patients died or were hospitalized for HF at 3-year follow-up and this was significantly related to impaired left ventricular long-axis function during exercise.

Deterioration of left ventricular systolic function in extended Pacing to Avoid Cardiac Enlargement (PACE) trial: the predictive value of early systolic dyssynchrony.

AIMS: Biventricular (BiV) pacing was superior to right ventricular apical (RVA) pacing at extended follow-up in the Pacing to Avoid Cardiac Enlargement (PACE) trial. Early pacing-induced systolic dyssynchrony (DYS) might be related to mid-term result. However, it remains unknown whether early pacing-induced DYS can predict long-term reduction of left ventricular (LV) systolic function. METHODS AND RESULTS: Patients with standard pacing indications and normal LV ejection fraction (LVEF) were randomized either to BiV (n = 89) or RVA (n = 88) pacing. Seventy-four patients in the RVA group and 72 in the BiV pacing group completed follow-up longer than 2 years. Serial echocardiography was performed with DYS assessed by tissue Doppler imaging, and the early pacing-induced DYS was defined as >33 ms by using standard deviation of the time to peak systolic velocity (Dyssynchrony Index) in a 12-segment model of LV at 1 month. There were 46 (32%) patients having early pacing-induced DYS that was more prevalent in the RVA pacing group than that in the BiV pacing group (50.7 vs. 12.3%, χ(2) = 25.1, P < 0.001) despite the similar DYS between the two groups at baseline (30 ± 13 vs. 26 ± 11 ms, P = 0.051). At a median follow-up of 4.8 years, patients developing early DYS had lower LVEF (53.2 ± 9.4 vs. 60.9 ± 8.0%, P < 0.001) and larger LV end-systolic volume (40.3 ± 23.7 vs. 29.3 ± 13.4 mL, P < 0.001) than those without DYS. Significant EF reduction (defined as ≥5%) occurred in 71.7% (33 in 46) of patients with DYS, but only in 30% (30 in 100) in those without DYS (χ(2) = 22.4, P < 0.001). Further analysis showed that both DYS at 1 month [odds ratio (OR): 3.113, P = 0.013] and RVA pacing (OR: 7.873, P < 0.001) independently predicted the deterioration of LV systolic function with pacing period of 4.8 years. CONCLUSION: Early pacing-induced DYS is a significant predictor of reduction of LV systolic function for long-term pacing, which could be prevented by BiV pacing at relatively long-period follow-up. CLINICAL TRIAL REGISTRATION: Centre for Clinical Trials number, CUHK_CCT00037 (URL: http://www.cct.cuhk.edu.hk/Registry/publictrialrecord.aspx?trialid=CUHK_CCT00037).

Changes of ventricular and peripheral performance in patients with heart failure and normal ejection fraction: insights from ergometry stress echocardiography.

AIMS: We assessed the left ventricular (LV) and peripheral performance at rest and during exercise in healthy and heart failure subjects with normal ejection fraction (HFNEF) or with reduced ejection fraction (HFREF). METHODS: All subjects received echocardiography at rest and with bicycle Ergometer exercise. The exercise images for two-dimensional speckle tracking were acquired with submaximal heart rate of 90-100 beats/min, while images for M-mode and tissue Doppler imaging were stored with attainment of >85% of predicted heart rate. RESULTS: A total of 80 HFNEF, 50 HFREF and 50 controls were studied. There was progressive decrease of two-dimensional global circumferential, radial and longitudinal strains (GCS, GRS and GLS), M-mode and tissue Doppler imaging long-axis parameters from controls, HFNEF to HFREF patients (all P < 0.05) at rest and on exercise. The degree of exercise-induced, long-axis augmentation (GLS and M-mode long axis excursion) decreased progressively from controls, HFNEF to HFREF subjects (all P < 0.05), while the increase in GCS and GRS was similar in all groups. The ventricular-arterial coupling ratio did not change in HFREF but reduced in HFNEF and controls during exercise (P < 0.01). All subjects had a similar resting heart rate, but patients exhibited chronotropic non-competence during exercise (P < 0.001). CONCLUSIONS: Ventricular and peripheral dysfunction was evident in HFNEF at rest and deteriorated during exercise. The HFNEF patients had significantly impaired long-axis augmentation at stress that was intermediate between HFREF patients and controls. These findings have relevance to generation of symptoms on exercise in both HFNEF and HFREF.

Quantification of left ventricular performance in different heart failure phenotypes by comprehensive ergometry stress echocardiography.

BACKGROUND: We evaluated the left ventricular (LV) performance in patients with heart failure and preserved ejection fraction (HFPEF) during exercise as compared to those with heart failure and reduced ejection fraction (HFREF) and healthy subjects. METHODS: All subjects received echocardiographic (Vivid7, GE Healthcare) examination with symptom-limited exercise testing on a semi-recumbent and tilting bicycle ergometer (Lode BV, Netherlands). The exercise images for 2-dimensional (2D) speckle tracking were acquired with heart rate of 90-100 bpm, while exercise images for tissue Doppler imaging (TDI) and M-mode echocardiography were stored with attainment of >85% of maximal age-predicted heart rate. RESULTS: Stress echocardiographic examinations were performed in 40 HFPEF (aged 65 ± 9 years; 53% male), 40 HFREF (aged 62 ± 9 years; 90% male) and 30 normal controls (aged 56 ± 5 years; 33% male). Trends of progressive decline in 2D global longitudinal, circumferential and radial strains (GLS, GCS and GRS); TDI septal s' and Sm; and M-mode mitral annular plane systolic excursion (MAPSE) were observed from control, HFPEF to HFREF groups (p<0.05 for all). LV twist was preserved in HFPEF but reduced in HFREF patients as compared to normal controls (p<0.05). Diastolic function measured by TDI septal e', Em and septal E/e' progressively decreased from controls, HFPEF to HFREF patients (all p<0.05). Stroke volumes and cardiac indices (LVSI & LVCI) were preserved in HFPEF but deteriorated in HFREF than controls. CONCLUSIONS: This study provides the reference values of LV performance during exercise in HFPEF and knowledge about these changes provide important insights for future clinical studies.

Early pacing-induced systolic dyssynchrony is a strong predictor of left ventricular adverse remodeling: analysis from the Pacing to Avoid Cardiac Enlargement (PACE) trial.

BACKGROUND: Right ventricular apical (RVA) pacing is associated with adverse left ventricular (LV) remodeling and biventricular (BiV) pacing may prevent it although the mechanisms remain unclear. The current study aimed to assess the role of early pacing-induced systolic dyssynchrony (DYS) to predict adverse LV remodeling. METHODS: Patients with standard pacing indications and normal LV ejection fraction were randomized either to BiV (n=89) or RVA pacing (n=88). Pacing-induced DYS, defined as the standard deviation of the time to peak systolic velocity (Dyssynchrony Index) >33 ms in a 12-segmental model of LV, was measured by tissue Doppler echocardiography at 1 month. RESULTS: At 1 month, 59 patients (33%) had DYS which was more prevalent in RVA than BiV pacing group (52% vs. 15%, χ(2)=28.3, p<0.001), though Dyssynchrony Index was similar at baseline (30 ± 14 vs. 26 ± 11 ms, p=0.06). At 12 months, those developing DYS had significantly lower LV ejection fraction (55.1 ± 9.7 vs. 62.2 ± 7.9%, p<0.001) and larger LV end-systolic volume (35.3 ± 14.3 vs. 27.0 ± 10.4 ml, p<0.001) when compared to those without DYS. Reduction of ejection fraction ≥ 5% occurred in 67% (39 out of 58) of patients with DYS, but only in 18% (21 out of 115) in those without DYS (χ(2)=40.8, p<0.001). Both DYS at 1 month (odds ratio [OR]: 4.725, p=0.001) and RVA pacing (OR: 3.427, p=0.009) were independent predictors for reduction of ejection fraction at 12 months. CONCLUSION: Early pacing-induced DYS is a significant predictor of LV adverse remodeling and the observed benefit of BiV pacing may be related to the prevention of DYS. CLINICAL TRIAL REGISTRATION: Centre for Clinical Trials number, CUHK_CCT00037 (URL: http://www.cct.cuhk.edu.hk/Registry/publictrialrecord.aspx?trialid=CUHK_CCT00037).

Quantitative analysis of mitral valve morphology in mitral valve prolapse with real-time 3-dimensional echocardiography: importance of annular saddle shape in the pathogenesis of mitral regurgitation.

BACKGROUND: Few data exist on the relation of the 3-dimensional morphology of mitral valve and degree of mitral regurgitation (MR) in mitral valve prolapse. METHODS AND RESULTS: Real-time 3-dimensional transesophageal echocardiography of the mitral valve was acquired in 112 subjects, including 36 patients with mitral valve prolapse and significant MR (≥3+; MR+ group), 32 patients with mitral valve prolapse but no or mild MR (≤2+; MR- group), 12 patients with significant MR resulting from nonprolapse pathologies (nonprolapse group), and 32 control subjects. The 3-dimensional geometry of mitral valve apparatus was measured with dedicated quantification software. Compared with the normal and MR- groups, the MR+ group had more dilated mitral annulus (P<0.0001), a reduced annular height to commissural width ratio (AHCWR) (P<0.0001) indicating flattening of annular saddle shape, redundant leaflet surfaces (P<0.0001), greater leaflet billow volume (P<0.0001) and billow height (P<0.0001), longer lengths from papillary muscles to coaptation (P<0.0001), and more frequent chordal rupture (P<0.0001). Prevalence of chordal rupture increased progressively with annulus flattening (7% versus 24% versus 42% for AHCWR >20%, 15%-20%, and <15%, respectively; P=0.004). Leaflet billow volume increased exponentially with decreasing AHCWR in patients without chordal rupture (r(2)=0.66, P<0.0001). MR severity correlated strongly with leaflet billow volume (r(2)=0.74, P<0.0001) and inversely with AHCWR (r(2)=0.44, P<0.0001). In contrast, annulus dilatation but not flattening occurred in nonprolapse MR patients. An AHCWR <15% (odds ratio=7.1; P=0.0004) was strongly associated with significant MR in mitral valve prolapse. CONCLUSION: Flattening of the annular saddle shape is associated with progressive leaflet billowing and increased frequencies of chordal rupture and may be important in the pathogenesis of MR in mitral valve prolapse.

Acute effects of right ventricular apical pacing on left atrial remodeling and function.

BACKGROUND: The acute effects of right ventricular apical (RVA) pacing on left atrial (LA) function in patients with normal ejection fraction are not clear. METHODS: A total of 94 patients (age 68.1 ± 11.1 years, 26 men) with implanted RVA-based dual-chamber pacemakers were recruited into this study. Patients who were pacemaker-dependent, in persistent atrial fibrillation or left ventricular ejection fraction <45% were excluded. Echocardiography (iE33, Philips, Andover, MA, USA) was performed during intrinsic ventricular conduction (V-sense) and RVA pacing (V-pace) with 15 minutes between switching modes. The total maximal LA volume (LAV(max)), preatrial contraction volume (LAV(pre)), and minimal volume (LAV(min)) were assessed by area-length method. Peak systolic, early diastolic, and peak late diastolic (atrial contractile) velocity (Sm-la, Em-la, and Am-la) and strain (ɛs-la, ɛe-la, and ɛa-la) were measured by color-coded tissue Doppler imaging (TDI) in four mid-LA walls at apical four- and two-chamber views. RESULTS: During V-pace, LA volumes increased significantly compared with V-sense (LAV(max): 52.0 ± 18.8 vs 55.2 ± 21.1 mL, P = 0.005; LAV(pre): 39.8 ± 16.4 vs 41.3 ± 16.6 mL, P = 0.014; LAV(min): 27.4 ± 14.0 vs 29.1 ± 15.1 mL, P = 0.001). TDI parameters showed significant reduction in Sm-la and Em-la. Furthermore, ɛs-la, ɛe-la, and ɛa-la decreased significantly, especially in patients with preexisting diastolic dysfunction (all P < 0.01). CONCLUSIONS: RVA pacing acutely induced LA enlargement and impaired atrial contractility. Patients with preexisting diastolic dysfunction may be more vulnerable to develop LA dysfunction and remodeling after acute RVA pacing.

Atrial dysfunction and interatrial dyssynchrony predict atrial high rate episodes: insight into the distinct effects of right atrial appendage pacing.

INTRODUCTION: Right atrial (RA) appendage pacing may prolong atrial conduction time (ACT). This study aimed to investigate if RA appendage pacing can induce intra- and interatrial dyssynchrony and if atrial dysfunction and dyssynchrony can predict atrial high rate episodes (AHREs) in the first year after pacing. METHODS AND RESULTS: Patients implanted with dual-chamber pacemakers for symptomatic bradycardia were enrolled. Cumulative percentage of RA appendage pacing (Cum%AP) during 1-year follow-up and AHREs were recorded. Full Doppler echocardiography studies were performed before implantation and 1 year after pacing. ACT and peak atrial velocities (Sm-la, Em-la, Am-la) were measured. One hundred ten patients (age 70.5 ± 11 years; 53 males) were recruited and completed 1-year follow-up. ACT of both RA and left atrial (LA) were more prolonged in patients with Cum%AP > 75% than those with <25%. Intra- and interatrial dyssynchrony was more obvious in patients with Cum%AP > 75% (22.3 ± 12.2 milliseconds vs 9.5 ± 6.2 milliseconds; 53.9 ± 29.7 milliseconds vs 19.7 ± 17.3 milliseconds; both P < 0.001). AHREs occurred in 29% of patients. Atrial pump function and interatrial dyssynchrony independently predicted AHREs in multivariate analysis. Receiver operating characteristic curve provided a cutoff value of Am-la <5.3 cm/s, which predicted AHREs with a sensitivity of 71% and a specificity of 75% (area under the curve, 0.822; P < 0.001). CONCLUSION: RA appendage pacing causes atrial conduction delay with intra- and interatrial dyssynchrony. Atrial dysfunction and interatrial dyssynchrony are related to AHREs in the first year after pacing.

Impact of a dedicated training program on the reproducibility of systolic dyssynchrony measures using tissue Doppler imaging.

BACKGROUND: The reproducibility of the measurement of mechanical dyssynchrony by echocardiography including Doppler tissue imaging has recently been questioned. The aim of this study was to ascertain the role of a dedicated training program to improve skills and the reproducibility of dyssynchrony assessment. METHODS: In 70 patients with heart failure, color Doppler tissue images were acquired, and the time to peak systolic velocity of each segment and several dyssynchrony indices, including the standard deviation of time to peak systolic velocity, were measured by an expert to constitute a reference standard. The same images were then assessed by two beginners, who had only basic knowledge of dyssynchrony analysis after a 1-hour lecture, and two graduates, who had received a structured hands-on training program. Both sets of results were compared with the standard. RESULTS: For the standard deviation of time to peak systolic velocity, the linear correlations between the standard and beginner 1 (r = 0.643) and beginner 2 (r = 0.532) were only modest (P < .001 for both). When referenced to the standard, interobserver variability was 18% for beginner 1 and 19% for beginner 2. Measurements with differences of ≥10 msec were found in 24% and 22% of cases by beginners 1 and 2, respectively. In contrast, the assessments made by graduates 1 and 2 were significantly improved. The correlation coefficients were 0.935 and 0.929 (P < .001 for both), and interobserver variability values were 8% and 7%. The prevalence rates of measurements with differences ≥ 10 msec were 1.5% and 3%, respectively. CONCLUSIONS: There is a learning curve for the measurement of systolic dyssynchrony using Doppler tissue imaging, but good reproducibility can be achieved by the use of a dedicated training program.

Left atrial remodeling and reduced atrial pump function after chronic right ventricular apical pacing in patients with preserved ejection fraction.

BACKGROUND: This prospective study was to examine the impact of right ventricular apical (RVA) pacing on atrial remodeling and function. METHODS AND RESULTS: 103 patients (age 70 ± 11 years; 53 men) with preserved left ventricular (LV) ejection fraction (LVEF>45%) who received RVA pacing had Doppler echocardiography performed at baseline and after one year follow up. At one year follow up, left atrial (LA) volumes (pre-atrial contraction volume and the minimal volume) and their indexes were significantly increased with reduction in passive emptying fraction and total emptying fraction (all p<0.05). LA segmental tissue velocities - mean peak systolic (Sm-la), peak early diastolic (Em-la) and late diastolic (Am-la) - were also significantly reduced (all p<0.001). A reduction of Am-la>30% occurred in 24% of patients, and was more prevalent in patients with an elevation of LV filling pressure (E/e'>15) at one year (44.1% vs. 11.7%, χ(2)=12.75, p<0.001) as well as those with a reduction of LVEF ≥ 5% (34.0% vs. 14.3%, χ(2)=5.140, p=0.023). By multivariate regression analysis, E/e'>15 at one year (odds ratio [OR] 5.213; 95% confidence interval [CI] 1.778-15.281) and reduction of LVEF ≥ 5% (OR 3.181; 95% CI 1.045-9.686) were independent predictors of reduction of Am-la>30%. CONCLUSIONS: Chronic RVA pacing results in LA remodeling and reduced atrial function. This is related to elevated filling pressures and impairment of LV systolic function.

Deleterious effect of right ventricular apical pacing on left ventricular diastolic function and the impact of pre-existing diastolic disease.

AIMS: Right ventricular apex (RVA) pacing may have deleterious effects on left ventricular (LV) systolic function, but its impact on LV diastolic function has not been explored. METHODS AND RESULTS: Ninety-seven patients with sinus node dysfunction and ejection fraction (EF) ≥ 50% with permanent RVA pacing were randomly programmed to V-sense and V-pace modes and examined by echocardiography. Tissue Doppler imaging was employed to assess myocardial systolic velocity (S') and early diastolic velocity (E') at the mitral annulus. Systolic dyssynchrony was assessed using 12 LV segmental model (Ts-SD). Switching from V-sense to V-pace resulted in the worsening of both diastolic and systolic functions as shown by the decreased EF, reduced mean E' and S' velocities, as well as increase in LV volume and Ts-SD (all P< 0.001). Reduction of mean E' and S' of ≥ 1 cm/s occurred in 35 (36%) and 45 (46%) patients, respectively. In pre-defined subgroup analysis, only patients with pre-existing LV diastolic dysfunction had a significant reduction of mean E' and S' (both P< 0.001) even after age adjustment. Multivariate logistic regression analysis showed that independent factors for the reduction of mean E' ≥ 1 cm/s or mean S' ≥ 1 cm/s at V-pace were pre-existing LV diastolic dysfunction [odds ratio (OR): 4.735, P= 0.007 for E'; OR: 3.307, P= 0.022 for S'] and systolic dyssynchrony at V-pace (OR: 5.459, P= 0.007 for E'; OR: 2.725, P= 0.035 for S'). CONCLUSION: In patients with preserved EF, RVA pacing is associated with the deterioration of both LV diastolic and systolic functions, which is particularly obvious in those with pre-existing LV diastolic dysfunction and V-pace-induced systolic dyssynchrony.

LV mechanical dyssynchrony in heart failure with preserved ejection fraction complicating acute coronary syndrome.

OBJECTIVES: The aim of this study was to evaluate the role of left ventricular (LV) mechanical dyssynchrony in heart failure with preserved ejection fraction (HFPEF) complicating acute coronary syndrome (ACS). BACKGROUND: In systolic heart failure, LV mechanical dyssynchrony worsens cardiac function and cardiac resynchronization therapy improves clinical outcome. The role of LV mechanical dyssynchrony in HFPEF complicating ACS is unknown. METHODS: One hundred two patients presenting with ACS (ejection fraction ≥50%) and 104 healthy controls were studied using tissue Doppler imaging: group 1 (n = 55) had HFPEF on presentation and group 2 (n = 47) had no clinical HFPEF. The SD of time to peak systolic myocardial velocity and the SD of early diastolic (Te-SD) myocardial velocity of 12 LV segments were obtained for evaluation of dyssynchrony. Longitudinal mean myocardial ejection systolic velocity (mean Sm) and mean early diastolic velocity (mean Em) were measured. RESULTS: Te-SD was greater in group 1 (33 ± 13 ms) than group 2 (21 ± 9 ms) (p < 0.001), and diastolic mechanical dyssynchrony was evident in 35% of patients in group 1 but in only 9% in group 2 (p < 0.001). Conversely, the SD of time to peak systolic myocardial velocity was similar in the 2 ACS groups (34 ± 16 ms vs. 32 ± 18 ms; p = NS), showing a similar prevalence of systolic mechanical dyssynchrony (47% vs. 43%; p = NS). Worsening of the diastolic dysfunction grade was associated with a parallel increase in Te-SD (grades 0, 1, 2, and 3: 16 ± 3 ms, 21 ± 5 ms, 28 ± 9 ms, and 41 ± 17 ms, respectively; p < 0.001). Te-SD correlated negatively with mean Em (r = -0.56, p < 0.001) and positively with peak mitral inflow velocity of the early rapid-filling wave/Em (r = 0.69, p < 0.001); mean myocardial ejection systolic velocity correlated significantly with mean Em (r = 0.56, p < 0.001), SD of time to peak systolic myocardial velocity (r = -0.42, p < 0.001) and Te-SD (r = -0.23, p = 0.001). Multivariate analysis identified peak mitral inflow velocity of the early rapid-filling wave/Em as the only variable independently associated with HFPEF (odds ratio: 1.48, p = 0.001). When peak mitral inflow velocity of the early rapid-filling wave/Em was excluded from the model, Te-SD (odds ratio: 1.13, p < 0.001) and mean Em (odds ratio: 0.37, p < 0.001) became independently associated with HFPEF. CONCLUSIONS: LV diastolic mechanical dyssynchrony may impair diastolic function and contribute to the pathophysiology of HFPEF, complicating ACS.

Resting global and regional left ventricular contractility in patients with heart failure and normal ejection fraction: insights from speckle-tracking echocardiography.

UNLABELLED: OBEJCTIVE: To compare left ventricular (LV) systolic performance and contractility in patients with heart failure and normal ejection fraction (HFNEF), compared with patients with heart failure and reduced ejection fraction (HFREF) and healthy subjects using newer echocardiographic techniques. DESIGN: A case-control trial. SETTING: University teaching hospital (tertiary referral centre). PATIENTS: Sixty healthy control subjects (53 ± 10 years), 112 patients with HFNEF (74 ± 12 years) and 175 patients with HFREF (67 ± 13 years). INTERVENTIONS: All underwent standard two-dimensional, Doppler and speckle-tracking echocardiography. MAIN OUTCOME MEASURES: Effective arterial (Ea) and LV end-systolic elastance (Ees), stress-corrected mid-wall shortening, preload recruitable stroke work, two-dimensional strain and torsion. Comparisons were adjusted for age, gender and body size. RESULTS: Besides diastolic dysfunction, patients with HFNEF had impaired load-independent ventricular contractility with a progressive decrease of the corrected Ees from controls (2.9 ± 0.8 mm Hg/g) to HFNEF (2.2 ± 0.9 mm Hg/g) followed by HFREF (0.8 ± 0.3 mm Hg/g; all p<0.001). Ventricular-arterial coupling ratio was preserved in the HFNEF subgroup (normal 0.48 ± 0.09 vs 0.65 ± 0.16; p = NS) at the expense of both increased LV systolic stiffness and Ea. In addition, there was progressive decrease of global 2D circumferential, radial and longitudinal strain as well as torsion from normal, HFNEF to HFREF groups, even after adjustment for LV end-systolic wall stress or end-diastolic volume (all p<0.01). About 50% of patients with HFNEF had ≥ 1 global strain or torsion parameter depressed below normal after correction for LV end-systolic wall stress, with >85% falling below their corresponding stress-corrected mean. CONCLUSIONS: Impaired myocardial contractility is evident in many patients with HFNEF and this may contribute towards pathophysiology of HFNEF more than previously thought.

A novel multi-layer approach of measuring myocardial strain and torsion by 2D speckle tracking imaging in normal subjects and patients with heart diseases.

BACKGROUND: This study adopted a new multi-layer approach of measuring myocardial deformation by two-dimensional (2D) speckle tracking imaging to examine whether a transmural gradient exists in normal subjects and cardiac diseases. METHODS: Eighty patients were included with 20 in each group: (1) normal control; (2) acute coronary syndrome (ACS) with ejection fraction (EF) >45%; (3) right ventricular apical (RVA) pacing with EF>45%; (4) systolic heart failure (SHF) with EF<45%. Circumferential strain (ε-circum), torsion (Tor) and systolic dyssynchrony defined as the maximal difference in the time to peak circumferential strain were measured in the subendocardial and subepicardial myocardium layers (QLab 6.0, Philips). RESULTS: In all the 4 groups, a subendocardial to subepicardial gradient was present in both ε-circum (-20.7 ± 7.6 vs. -14.9 ± 5.6%, p<0.001) and Tor (12.0 ± 6.0 vs. 9.3 ± 4.7°, p<0.05), with higher values in the subendocardial layer. However, it was significantly narrowed for ε-circum (2.7 ± 1.2%) and Tor (0.8 ± 0.9°) in SHF patients (all p ≤ 0.001 vs. other groups). On the contrary, systolic dyssynchrony measured in the 2 layers showed no difference (264 ± 107 vs. 273 ± 110 ms, p = NS) and a homogenous distribution in ε-circum was observed from basal to apical planes (-17.0 ± 6.8 vs. -18.1 ± 7.4 vs. -18.1 ± 7.8%, all p = NS). CONCLUSIONS: A transmural gradient exists in circumferential strain and torsion, with higher values in the subendocardial layer. It might be reduced when systolic function is impaired. Therefore, the multi-layer approach of 2D speckle tracking imaging provides further information on assessment of myocardial diseases.

Prevalence and determinants of left ventricular systolic dyssynchrony in patients with normal ejection fraction received right ventricular apical pacing: a real-time three-dimensional echocardiographic study.

AIMS: Right ventricular apical (RVA) pacing may induce mechanical dyssynchrony. However, its impact on patients with normal ejection fraction (EF) is not fully understood. This study examined the prevalence and predictors of RVA pacing-induced systolic dyssynchrony by real-time three-dimensional echocardiography (RT3DE), and evaluated its impact on left ventricular (LV) function. METHODS AND RESULTS: Ninety-three patients with sinus node dysfunction and normal EF (>50%) received RVA-based dual-chamber pacing were assessed by RT3DE during RVA pacing (V-pace) and intrinsic conduction (V-sense). Systolic dyssynchrony was evaluated using the standard deviation of the time to minimal regional volume of 16 LV segments (Tmsv-16SD), and a cutoff value of 16 ms was determined from 93 normal controls. Systolic dyssynchrony was induced in 49.5% of patients at V-pace with significant increase in LV end-systolic volume (LVESV), decrease in EF, and worsening of Tmsv-16SD (all P < 0.001). Furthermore, patients who developed dyssynchrony had larger LVESV (P < 0.001), lower EF (P < 0.001) at V-pace mode, and higher cumulative percentage of RVA pacing in the past 6 months (P < 0.001) than those without systolic dyssynchrony. In multivariate logistic regression analysis, independent predictors of developing LV systolic dyssynchrony during V-pace included a low normal EF at V-sense, pre-existing LV hypertrophy, and cumulative RVA pacing >40% in the past 6 months. CONCLUSION: For patients with preserved EF received RVA pacing, half of them would develop systolic dyssynchrony which was associated with EF deterioration and LV enlargement. A low normal EF, a high cumulative percentage of RVA pacing, and pre-existing LV hypertrophy were predictors of developing dyssynchrony.