Total Isovolumic Time Research Articles

Echocardiographic evaluation of ventricular performance in VA-ECMO weaning: results from a observational monocentric prospective study

Abstract Background Although temporary mechanical circulatory support (MCS) devices are increasingly used in the management of cardiogenic shock (CS), several open question regarding the kind of support and timing of institution/weaning remains open. Echocardiography is widely applied to drive the weaning process and decision although there are no standardized protocols for the trial nor accordance on the parameters to apply. Purpose We sought to evaluate the overall accuracy of echocardiographic indices in predicting successful weaning from VA ECMO in patients with CS. Specifically, we tested total isovolumic time (tIVT), an index of ventricular performance, and longitudinal function (MAPSE) on top of the commonly used parameters (left ventricular ejection fraction, LVEF; left ventricular velocity time integral, LV VTI; TAPSE; right ventricular S’ at tissue Doppler imaging, RV S’). Methods Monocentric prospective study on adults receiving VA-ECMO due to refractory CS and/or cardiac arrest (CA) from 2012 to 2020. Echocardiography was performed at VA-ECMO placement and during the weaning trials. Weaning trials were performed daily, starting 48 hours after VA-ECMO institution, when patients were hemodynamically stable: mean arterial pressure >65 mmHg, no or minimum adrenergic support (vasoactive inotropic score <10), heart rate <110 bpm, lactate <2 mmol/L, and no signs of respiratory distress. Weaning trials were performed with a stepwise decrease of VA-ECMO blood flow until reaching 1 or 1.5 L/min under adequate anticoagulation. Successful weaning was defined as removal of VA-ECMO with no requirement for further MCS in the following 30 days. Results 76 patients were enrolled (23.8% female, 54.2±10.6 years-old), 52.6% due to CA. Median duration of VA-ECMO was 58 hours; 47 (61.8%) had intra-aortic balloon pump (IABP) inserted upfront. In-hospital mortality was 62.4% overall, 40% for CS without CA. 6 of the 32 weaned patients died for multiorgan failure due to septic shock. The baseline echocardiographic parameters associated with successful weaning were (table): stroke volume >13.9 mL (p 0.002), tIVT >23.6 min/sec (p 0.053), LV VTI >6.6 cm (p<0.001), MAPSE >6.15 mm (p 0.001), TAPSE >11 mm (p 0.023), RV S’ >10 cm/s (p 0.012). LVEF did not reach the statistical significance. Figure shows Kaplan-Meier analysis on echocardiographic indices collected at time of cannulation (panel A) and during the last weaning trial (panel B). Conclusions Echocardiography is pivotal in defining cardiac recovery and monitoring the weaning trial. Indices reflecting ventricular performance and delivered flow from LV were associated with weaning success both at VA-ECMO institution and throughout the weaning trials. Considering the known limitations of LVEF (heart rate, loading and left ventricular dyssynchrony dependence), tIVT and MAPSE should be introduced in the standard evaluation of patients in the acute setting.TableFigure

Echocardiographic parameters for weaning from Extracorporeal Membrane Oxygenation - the role of longitudinal function and cardiac time intervals.

Limited data exist on echocardiographic predictors of weaning from veno-arterial extracorporeal membrane oxygenation (V-A ECMO). We aimed to test the performance of different echocardiographic indices to predict weaning from V-A ECMO. and free survival after weaning. Observational study including patients with cardiogenic shock submitted to V-AECMO. Echocardiography was performed after V-AECMO placement and daily during the weaning trial to assess cardiac recovery. Echocardiography data after V-A ECMO implantation and during the last weaning-trial before V-A ECMO removal were analyzed. Besides traditional parameters, total isovolumic time (t-IVT, a left ventricular performance index) and mitral annular plane systolic excursion (MAPSE) were also tested.76 patients were included. A greater ventricular velocity-time integral (LVOT VTI) at baseline was associated with a 5-fold increase in weaning success (p < 0.001) as MAPSE lateral >6.15 mm (p 0.001) did. TAPSE and S' at tricuspid annulus showed an analogous association. During the weaning trial t-IVT, LVEF, MAPSE, LVOT VTI and TAPSE all improved significantly (p <0.001 for all). At regression analysis t-IVT <14.4second/minute (<0.001), LVOT VTI >12.3cm (p <0.001), MAPSE >8.9mm (p < 0.001), TAPSE> 16mm (<0.001) and E/e' <15.5 (p 0.001) were associated with weaning success and free survival after weaning. LVEF did not predict the weaning success and survival at any time-point (p 0.230). Longitudinal function, t-IVT and native ejection, measured with LVOT VTI, are reliable parameters to predict weaning success in V-A ECMO whereas the LVEF, although dynamically changing during weaning trial, it is not.

Echocardiographic evaluation of ventricular performance in VA-ECMO weaning: results from a observational multicentric prospective study

Abstract Funding Acknowledgements None. Background Although temporary mechanical circulatory support devices are increasingly used in the management of cardiogenic shock (CS), several open question regarding the kind of support and timing of institution/weaning remains open. Echocardiography is widely applied to drive the weaning process from VA-ECMO although there are no standardized protocols. Purpose We sought to evaluate the accuracy of echocardiographic indices in predicting successful weaning from VA-ECMO in CS patients. We tested total isovolumic time (tIVT), an index of ventricular performance(1,2), and longitudinal function (MAPSE) on top of the commonly used parameters (left ventricular ejection fraction, LVEF; E/e’ at mitral valve; left ventricular velocity time integral, LV VTI; TAPSE; right ventricular S’ at tissue Doppler imaging, RV S’). Methods Multicentric prospective study on adults receiving VA-ECMO due to refractory CS and/or cardiac arrest (CA) from 2012 to 2020. Echocardiography was performed at VA-ECMO placement and during the weaning trials. Waning trials were performed daily starting from 48 hours after VA-ECMO institution. A stepwise decrease of VA-ECMO blood flow was applied, until reaching 1 or 1.5 L/min. Successful weaning was defined as removal of VA-ECMO with no requirement for further MCS in the following 30 days. Results 76 patients were enrolled (23.8% female, 54.2±10.6 years-old), 52.6% due to CA. Median duration of VA-ECMO was 58 hours; 47 (61.8%) had intra-aortic balloon pump (IABP) inserted upfront. In-hospital mortality was 62.4% overall, 40% for CS without CA. 6 of the 32 weaned patients died in hospital for multiorgan failure due to septic shock. The baseline echocardiographic parameters associated with successful weaning were (Figure 1-A): stroke volume (SV) &amp;gt;13.2 ml (HR 4.12 [1.71-9.95], p 0.002), tIVT &amp;gt;23.6 min/sec (HR 0.14 [0.02-1.03], p 0.053), LV VTI &amp;gt;6.6 cm (HR 4.99 [1.94-12.87], p&amp;lt;0.001), MAPSE &amp;gt;6.15 mm (HR 4.42 [1.90-10.24], p 0.001), TAPSE &amp;gt;11 mm (HR 10.13 [1.37-7.02], p 0.023), RV S’ &amp;gt;7 cm (HR 5.40 [1.45-20.12], p 0.012). LVEF, E/e’ and S’ at mitral valve did not reach the statistical significance. Figure 1-B shows Kaplan-Meier analysis on echocardiographic indices collected during the last weaning trial; figure 2 details HR of all these parameters. Conclusions Echocardiography is pivotal in defining cardiac recovery and monitoring the weaning trial. Indices reflecting ventricular performance and delivered flow from LV were associated with weaning success both at VA-ECMO institution and throughout the weaning trials. Parameters reflecting ventricular activation and systo-diastolic interaction already demonstrated superiority in defining ventricular performance. Considering the known limitations of LVEF (HR, loading and LV dyssynchrony dependence), tIVT and MAPSE should be introduced in the standard evaluation in the acute setting.

Echocardiographic assessment of right ventricular performance in COVID-19 related acute respiratory distress syndrome: the importance of systo-diastolic interaction.

The cardiac manifestations of COVID-19 have been described in patients with acute respiratory distress syndrome (ARDS) admitted to intensive care unit (ICU). The presence and impact of right ventricular (RV) diastolic function and performance has not been studied in this population yet. We describe the prevalence of RV diastolic dysfunction, assessed by the pulmonary valve pre-ejection A wave (PV A wave), and the RV systo-diastolic interaction, using the RV total isovolumic time (t-IVT), in COVID-19 ARDS. Prospective observational study enrolling patients with moderate to severe COVID-19 ARDS admitted to ICU who underwent a transthoracic echocardiogram within 24h of ICU admission and at least a second one during the ICU stay. Respiratory, hemodynamic and biochemistry parameters were collected. 163 patients (age 61.0 ± 9.3years, 72% males) were enrolled. 36 patients (22.1%) had RV dysfunction, 45 (27.1%) LV systolic dysfunction. 73 patients (44.7%) had PV A wave. The RV t-IVT correlated with TAPSE at ICU admission (p < 0.002; r -0.61), presence of PV A wave (p < 0.001; r 0.78), peak inspiratory pressure (PIP) (p < 0.001; r 0.42), PEEP (p < 0.001; r 0.68), dynamic driving pressure (DDP) (p < 0.001; r 0.58), and PaO2/FiO2 ratio (p < 0.01; r -0.35). The presence of PV A wave was associated with higher PIP (p < 0.001; r 0.45), higher PEEP (p < 0.001; r 0.56), higher DDP (p < 0.01, r 0.51), and lower PaO2/FiO2 ratio (p < 0.001; r -0.49). RV t-IVT and the presence of PV A wave are non-invasive means to describe a significant RV diastolic dysfunction and may be consider descriptive signs of RV performance in COVID-19 ARDS.

Left Ventricular Myocardial and Cavity Velocity Disturbances Are Powerful Predictors of Significant Coronary Artery Stenosis.

Background and Aim: Dobutamine stress echocardiography (DSE) is a well-established noninvasive investigation for significant coronary artery disease (CAD). The aim of this study was to evaluate the accuracy of cardiac Doppler parameters in predicting CAD. Methods: We prospectively studied 103 consecutive patients with suspected CAD based on typical symptoms; 59 proved to have CAD, and 44 patients proved to have no-CAD (n = 44). All patients underwent a complete stress Doppler echocardiographic examination. Total isovolumic time (T-IVT) as a marker of cavity dyssynchrony and wall motion score index (WMSI) were also calculated. Results: At peak dobutamine stress, the compromised LV longitudinal excursion (MAPSE), systolic septal and lateral velocities (s’), and diastolic indices were more pronounced in the CAD patients compared with those without CAD, but LV dimension did not differ between groups (p > 0.05). The WMSI was higher and t-IVT more prolonged in patients with CAD (p < 0.01 for both). Similarly, the changes were more pronounced in patients with significant CAD compared with insignificant CAD. On multivariate model, Δ mean s’, OR 2.016 (1.610 to 3.190; p < 0.001), Δ E velocity OR 2.502 (1.179 to 1.108; p < 0.001), Δ t-IVT 2.206 (1.180 to 2.780; p < 0.001) and Δ WMSI OR 1.911 (1.401 to 3.001; p = 0.001) were the most powerful independent predictors of the presence of CAD, particularly when significant (>75%). Δ mean s’ < 5.0 was 85% sensitive, 89% specific with AUC 0.92. Respective values for Δ E velocity <6.0 cm/s were 82%, 90% and 0.91; for Δ t-IVT > 4.5, 78%, 77% and 0.81 and for Δ FT ≥ 150 ms, 76%, 78% and 0.84 in predicating significant CAD. WMSI ≥ 0.7 was 75% sensitive, 77% specific with AUC of 0.81 in predicting significant CAD. The accuracy of DSE was higher in significant CAD compared to insignificant CAD (80% vs. 74%; p = 0.03). Conclusions: Compromised LV longitudinal systolic function, lower delta E wave, prolonged t-IVT, and increased WMSI were the most powerful independent predictors of the presence and significance of CAD. These finding strengthen the role of comprehensive DSE analysis in diagnosing ischemic disturbances secondary to significant CAD.

Left ventricular myocardial and cavity velocity disturbances are stronger predictors of stress induced ischaemia in patients with significant coronary artery disease

Abstract Background and aim Dobutamine stress echocardiography (DSE) is a well-established non-invasive investigation for significant coronary artery disease (CAD). The aim of this study was to evaluate the accuracy of cardiac Doppler parameters in predecting CAD. Methods We prospectively studied 103 consecutive patients with suspected CAD based on typical symptoms, 59 proved to have CAD and 44 patients proved to have no-CAD (n=44). All patients underwent a complete stress Doppler echocardiographic examination, including tissue Doppler, long axis velocities and total isovolumic time (T-IVT) as a marker of cavity dyssynchrony, determined as [60 − (total ejection time (ET) + total filling time (FT))]. The wall motion score index (WMSI) was also calculated. Results CAD patients were older, had less females, less prevalent cardiac risk factors and higher CT calcium score compared to patients with no-CAD (p&amp;lt;0.05, for all). At peak dobutamine stress the compromised LV longitudinal excursion (MAPSE), systolic septal and lateral velocities (s'), TAPSE and diastolic indices were more pronounced in the CAD patients compared to those without CAD, but LV dimension did not differ between groups (p&amp;gt;0.05). The WMSI was higher and t-IVT more prolonged in patients with CAD (p&amp;lt;0.01, for both). Similarly, the changes were more pronounced in patients with significant CAD compared to insignificant CAD. On multivariate model, delta mean s' OR 2.016 (1.610–3.490, p&amp;lt;0.001), delta E velocity OR 1.822 (1.179–2.360, p&amp;lt;0.001), delta t-IVT OR 1.406 (1.180–2.180, p&amp;lt;0.001), and delta FT OR 1.911 (1.401–2.710, p=0.001), were the most powerful independent predictors of the presence of CAD, particularly when significant (&amp;gt;50%). Delta mean s' &amp;lt;5.0 was 85% sensitive, 89% specific with AUC 0.92. Respective values for delta E velocity &amp;lt;6.0 cm/s were 82%, 90% and 0.91; for delta t-IVT &amp;gt;4.5, 78%, 77% and 0.81 and for delta FT ≥150ms, 76%, 78% and 0.84 in predicating significant CAD. WMSI≥0.7 was 75% sensitive, 77% specific with AUC of 0.81 in predicting significant CAD. The accuracy of DSE was higher in significant CAD compared to insignificant CAD (80% vs 74%; p=0.03). Conclusions Compromised LV longitudinal systolic function, lower delta E wave, prolonged t-IVT and increased WMSI were the most powerful independent predictors of the presence and significance of CAD. These finding strengthen the role of comprehensive DSE analysis in diagnosing ischaemic disturbances secondary to significant CAD. Funding Acknowledgement Type of funding sources: None.

Diastolic Dysfunction in Neonates With Hypoxic-Ischemic Encephalopathy During Therapeutic Hypothermia: A Tissue Doppler Study.

Diastolic dysfunction often complicates myocardial ischemia with increased mortality rates. However, less is known about diastolic function after perinatal asphyxia in neonates with hypoxic-ischemic encephalopathy (HIE) during therapeutic hypothermia (TH) and rewarming.AimThe aim of this study was to assess diastolic function with tissue Doppler imaging (TDI) in neonates with moderate–severe HIE during TH and rewarming.MethodNewborns at >36 weeks' gestation with moderate–severe HIE treated with TH were evaluated with targeted neonatal echocardiography (TNE), including TDI, within 24 h of TH initiation (T1), at 48–72 h of treatment (T2), and after rewarming (T3). These retrospective data were collected and compared with a control group of healthy babies at >36 weeks' gestation that was prospectively evaluated following the same protocol.ResultsA total of 21 patients with HIE + TH and 15 controls were included in the study. Myocardial relaxation before the onset of biventricular filling was prolonged in the HIE + TH group during TH with significantly longer isovolumic relaxation time (IVRT') in the left ventricle (LV), the septum, and the right ventricle (RV). This was associated with slower RV early diastolic velocity (e') and prolonged filling on T1. Total isovolumic time (t-IVT; isovolumic contraction time [IVCT'] + IVRT') and myocardial performance index (MPI') were globally increased in asphyxiated neonates. All these differences persisted after correction for heart rate (HR) and normalized after rewarming. TDI parameters assessing late diastole (a' velocity or e'/a' and E/e' ratios) did not differ between groups.ConclusionTDI evaluation in our study demonstrated a pattern of early diastolic dysfunction during TH that normalized after rewarming, whereas late diastole seemed to be preserved. Our data also suggest a possible involvement of impaired twist/untwist motion and dyssynchrony. More studies are needed to investigate the impact and therapeutic implication of diastolic dysfunction in these babies, as well as to clarify the role of TH in these findings.

Right ventricular time intervals - Comparison between pulsed wave Doppler and tissue Doppler imaging.

Cardiac time intervals are used as indices of systolic and diastolic function. Echocardiographic assessment of these intervals is based on either pulsed wave Doppler (PWD) or tissue Doppler imaging (TDI). We investigated the agreement between the two techniques in the evaluation of right ventricular (RV) time intervals in healthy adults. In 123 healthy volunteers we used both PWD and TDI to assess RV time intervals (filling time - RVFT, ejection time - RVET), heart rate-corrected intervals (total filling time - t-FT, total ejection time - t-ET) and RV performance indices (total isovolumic time - t-IVT, myocardial performance index - MPI). Intraclass correlation coefficient (ICC) and Pearson analysis (r coefficient) were used to evaluate the agreement and correlation between the two techniques. PWD and TDI had excellent agreement and correlation in measuring RVFT (ICC 0.94 [95% CI 0.85 - 0.97], r 0.91) whereas a good agreement was found for RVET (ICC 0.63[95% CI - 0.14 - 0.84]; r 0.68). Good agreement and strong correlation were found for both t-FT (ICC 0.67 [95% CI 0.36 - 0.82]; r 0.59) and t-ET (ICC 0.71 [95% CI - 0.06-0.88]; r 0.74). The two methods had lower agreement in assessing RV t-IVT (ICC 0.52 [95% CI 0.3187-0.6622]; r 0.57) and MPI (ICC 0.36 [95% CI - 0.05-0.43]; r 0.50). In healthy adults, PWD and TDI are interchangeable in measuring RVFT, RVET, RV t-FT and RV t-ET. Lower agreement between the two techniques was found for RV t-IVT and MPI.

Exercise induced worsening of mechanical heterogeneity and diastolic impairment in Long QT syndrome

Abstract Funding Acknowledgements Type of funding sources: None. Background Left ventricular (LV) mechanical dispersion and prolonged myocardial contraction are associated with symptoms in long QT syndrome (LQTS) mutation carriers. Sub-clinical LV diastolic impairment has also been reported in this group. Purpose To investigate at rest and during exercise the combined effect of prolonged myocardial contraction and increased mechanical dispersion on myocardial diastolic function and symptoms in LQTS subjects. Methods 47 LQTS patients (36 LQT1, 11 LQT2) underwent a bicycle exercise test in semi-supine position. ECG and echo parameters were recorded at rest, peak exercise (p.e) and were compared with 35 healthy individuals. Results No difference was seen between LQTS and control subjects for age (45 ± 15 vs 47 ± 13 years, p = 0.2), gender (53 vs 54% females, p = 0.3) or LV Ejection Fraction (65 ± 6 vs 67 ± 7%, p = 0.3). LQTS subjects, compared to controls, had not only prolonged QTc interval, but also longer contraction duration (tGLS), total isovolumic time (t-IVT), delayed early relaxation phase (tESR) and markedly decreased filling time (FT) at rest and p.e. Unlike controls, these electromechanical disturbances deteriorated further with exercise, during which additional decrease of the LV systolic (GLS) and diastolic myocardial function (ESR) and attenuated LV stroke volume response (Δ SV: +2 ± 0.5 vs +4 ± 1 vs +32 ± 4%, p&amp;lt; 0.0001) were noted. Such abnormal response to exercise was of greater degree in symptomatic patients and in the LQT1 subgroup and appeared to be amplified by b-blocker therapy (p &amp;lt; 0.05). Worsening myocardial contraction dispersion (SD-tGLS) at p.e was the strongest discriminator for previous clinical events (AUC 0.960, 95% CI 0.020 - 0.995, p &amp;lt; 0.0001) and its discriminating power excelled further by adding early relaxation delay. Conclusions Our findings suggest that in LQTS subjects prolonged and dyssynchronous mechanical contraction during exercise may be associated with inadequate cardiac output increase and symptoms. Table 1. REST PEAK LQT CONTROL p- LQT CONTROL p- QTc (ms) 453 ± 42 413 ± 17 &amp;lt; 0.0001 455 ± 44 390 ± 19 &amp;lt; 0.0001 GLS (%) 17.3 ± 4.3 18.7 ± 1.3 0.05 19.1 ± 32.6 23.5 ± 11.6 0.0001 tGLS (%) 47 ± 7.2 42 ± 6.3 0.0001 58.7 ± 10 40.1 ± 5.8 &amp;lt; 0.0001 ESR (%) 1 ± 0.3 2 ± 0.3 &amp;lt; 0.0001 1.1 ± 0.4 2.8 ± 0.4 &amp;lt; 0.0001 tESR (%) 61.4 ± 6.8 58.7 ± 4.1 0.03 69.7 ± 5.9 56.1 ± 2.9 &amp;lt; 0.0001 SD TGLS (ms) 58 ± 8 31 ± 8 &amp;lt; 0.0001 61 ± 8 24 ± 10 &amp;lt; 0.0001 Exercise response in long QT syndrome patients and controls

P.851Differences in healthcare resource utilization across oral atypical antipsychotic treatments in patients with schizophrenia

The echocardiographic indices have not been validated in critically ill population. The authors investigated the correlation between some echocardiographic and hemodynamic parameters.Prospective, spontaneous, noninterventional observational study.Adult cardiothoracic intensive care unit, single center (Royal Brompton Hospital, London, United Kingdom).Consecutive adult patients admitted to the cardiothoracic intensive care unit for severe respiratory failure, primary cardiocirculatory failure, and post-aortic surgery.Clinical hemodynamic parameters (stroke volume [SV], cardiac output [CO], mean arterial pressure [MAP], and cardiac power index [CPI]) and echocardiographic indices of ventricular function (left ventricular total isovolumic time [t-IVT], mitral annular plane systolic excursion [MAPSE], and left ventricular fraction [LVEF]) were evaluated offline.The study comprised 117 patients (age 57.2 ± 19; 60.6% male). The t-IVT showed an inverse correlation with SV, CO, MAP, and CPI (r –67%; –38%; –45%; –51%, respectively). MAPSE exhibited a positive correlation with SV, CO, MAP, and CPI (r 43%; 44%; 34%; 31%, respectively). LVEF did not show any correlation. In the multivariate analysis the association between t-IVT and hemodynamics was confirmed for SV, CO, MAP, and CPI, with the highest partial correlation between t-IVT and MAP (R = –58%).MAPSE and t-IVT are 2 reproducible and reliable echocardiographic indices of systolic function and ventricular efficacy associated with hemodynamic variables in cardiothoracic critically ill patients, whereas LVEF did not show any correlation.

Correlation Between Echocardiographic and Hemodynamic Variables in Cardiothoracic Intensive Care Unit

The echocardiographic indices have not been validated in critically ill population. The authors investigated the correlation between some echocardiographic and hemodynamic parameters. Prospective, spontaneous, noninterventional observational study. Adult cardiothoracic intensive care unit, single center (Royal Brompton Hospital, London, United Kingdom). Consecutive adult patients admitted to the cardiothoracic intensive care unit for severe respiratory failure, primary cardiocirculatory failure, and post-aortic surgery. Clinical hemodynamic parameters (stroke volume [SV], cardiac output [CO], mean arterial pressure [MAP], and cardiac power index [CPI]) and echocardiographic indices of ventricular function (left ventricular total isovolumic time [t-IVT], mitral annular plane systolic excursion [MAPSE], and left ventricular fraction [LVEF]) were evaluated offline. The study comprised 117 patients (age 57.2 ± 19; 60.6% male). The t-IVT showed an inverse correlation with SV, CO, MAP, and CPI (r -67%; -38%; -45%; -51%, respectively). MAPSE exhibited a positive correlation with SV, CO, MAP, and CPI (r 43%; 44%; 34%; 31%, respectively). LVEF did not show any correlation. In the multivariate analysis the association between t-IVT and hemodynamics was confirmed for SV, CO, MAP, and CPI, with the highest partial correlation between t-IVT and MAP (R = -58%). MAPSE and t-IVT are 2 reproducible and reliable echocardiographic indices of systolic function and ventricular efficacy associated with hemodynamic variables in cardiothoracic critically ill patients, whereas LVEF did not show any correlation.

P895 Relationship between left ventricular function components and cardiovascular risk factors in asymptomatic individuals

Abstract Funding Acknowledgements none Background and Aim Coronary artery disease is commonly related to conventional cardiovascular (CV) risk factors. The exact role of those risk factors in early development of CV disease or left ventricular (LV) dysfunction before the development of sign and symptoms remains debated. We studied the relationship between conventional risk factors and LV systolic, diastolic and synchronous function in a population sample of asymptomatic individuals. Methods All participants underwent a detailed echocardiographic examination as part of a cross-sectional survey for the prevalence of coronary risk factors in randomly selected individuals from general population. LV end-systolic and end-diastolic dimensions, and LV volumes and ejection fraction (EF) were all calculated. From the spectral Doppler flow, LV early diastolic (E wave) and atrial systolic (A wave) velocities were measured and E/A ratio calculated. LV filling time (FT) was also measured from the onset of E wave to the end of A wave, and LV ejection time (ET) from the onset to the end of aortic Doppler velocity. Global LV dyssynchrony was assessed using total isovolumic time (T-IVT) as 60 – (total filling time + total ejection time), and Tei index was also calculated. Results The study population comprised 184 individuals (96 male and 88 female, mean age 55.9 (11.3), range 25-78 years). There was no relationship between systolic LV function expressed by EF and CV risk factors. Markers of diastolic function: LV filling velocities and E/A ratio, were correlated with age (r= -0.36, p &amp;lt; 0.000, r= -0.57, p &amp;lt; 0.000, respectively), with glycemia (r= -0.21, p &amp;lt; 0.000, r= -0.14, p = 0.004,) and with systolic blood pressure (r= -0.31, p &amp;lt; 0.000, r= -0.34, p &amp;lt; 0.000). Markers of LV dyssynchrony, in the form of prolonged T-IVT, and raised Tei index, directly correlated with age, glycemia and systolic blood pressure (r = 0.58, p &amp;lt; 0.000, r = 0.18, p &amp;lt; 0.000, r = 0.33, p &amp;lt; 0.000, respectively). However, when these correlations were adjusted for age in a multivariate analysis, the statistical significance was strongly reduced (LV filling) or completely lost (IVT and E/A). Conclusions In normal asymptomatic population, age, rather than CV risk factors, is the main determinant of changes in diastolic and synchronous function.

Right ventricular total isovolumic time: Reference value study.

There is lack of noninvasive indices to detail the right side cardiovascular physiology. Total isovolumic time (tIVT) is a sensitive marker of left ventricular electromechanical efficiency and systolic-diastolic interaction. The aim of the study was to evaluate normal reference value of the right ventricular tIVT with increasing age. One hundred and eighty-one healthy volunteers (51% male) underwent transthoracic echocardiography. The population was divided into four categories according to age: A<30years; B 30-39years; C 40-49years; and C≥50years old. tIVT was computed in seconds/minutes as: 60-(tET+tFT). tET and tFT are the total ejection and filling time adjusted by the heart rate, measured, respectively, from the onset to the end of the right ventricle (RV) forward flow through the pulmonary valve and from the onset of the E-wave and the end of the A-wave at the level of the tricuspid valve. The mean RV tIVT was 7±1.1s/min and increased significantly with age, from a 3.4 to 9.7s/min(P<0.0001). Significant correlation was found between tIVT and trans-tricuspid E/E' (P<0.0001; 0.78 (95% CI: 0.715-0.831) while weaker between tIVT and E/A (P=0.001; -0.283 95% CI: -0.413 to -0.143). The normal values of RV tIVT increase with age and correlate significantly with Doppler diastolic parameters.

The impact of age on cardiac electromechanical function in asymptomatic individuals.

Whether aging affects left ventricular (LV) filling and ejection and the LV electric function is not well established. We investigated the effect of normal aging on echocardiographic measurements of LV morphology and function, LV electric function and the relationship between LV electric and mechanical function in asymptomatic individuals. As part of a cross-sectional survey for the prevalence of coronary risk factors in the general population in Caltanissetta, Italy, individuals without signs or symptoms of coronary artery disease or heart failure were randomly selected and underwent electrocardiographic and echocardiographic examination. QRS duration and amplitude, PR, QT and QTc intervals, were automatically measured. Echocardiographic examination included the measurement of LV systolic and diastolic dimensions, volumes and ejection fraction (EF). From the spectral Doppler flow LV early diastolic (E wave) and atrial systolic (A wave) velocities, isovolumic relaxation time (IVRT) and isovolumic contraction time (IVCT) were measured. Global LV dyssynchrony was assessed using the total isovolumic time (T-IVT) and the Tei index. Aging reduced LV long-axis function, LV filling time and E wave velocity and prolonged T-IVT, IVRT and Tei index. It did not affect LV dimensions, ejection fraction, IVCT or QRS amplitude and duration. QRS duration correlated with LV dimensions, wall thickness and left atrial area. QRS amplitude and QTc interval correlated with the markers of LV dyssynchrony T-IVT and Tei index. Overall, systolic and electric LV function are not affected by age, whereas subendocardial function, diastolic and synchronous function are significantly influenced.

Heart Rate Modification of Cardiac Output Following Cardiac Surgery: The Importance of Cardiac Time Intervals.

Inadequate cardiac output is associated with a poor outcome following cardiac surgery and is generally modified by the use of positive inotropic agents, volume resuscitation, and pacing. Echocardiography-guided pacemaker optimization is used in the outpatient setting, using different variables including total isovolumic time and the Tei index. We sought to determine the acute impact of heart rate on cardiac electromechanics, cardiac output, and stroke volume in the perioperative setting. Observational study. Cardiothoracic adult intensive care department. Twenty-four sequential patients admitted after cardiac surgery. Patients with pacemaker set by the treating anesthesiologist using hemodynamic parameters in theatre, within 4 hours of returning to intensive care, they were reassessed using transthoracic echocardiography. A comprehensive baseline echocardiographic study was performed at the clinician set RR interval and at heart rates from 70 to 110 beats/min, in increments of 10 beats/min. Pearson correlation coefficients were used to assess relationships between the measurements. Cardiac output and cardiac index were increased significantly in 79% patients using echocardiography-guided pacemaker optimization (2.21 L/min [± 0.97] and 1.2 L/min/m [± 0.52]). The echocardiography-driven cardiac output optimization protocol led to a significant reduction of total isovolumic time with concurrent increase of cardiac output and cardiac index in the overall population (p < 0.001). There was no consistent correlation between changes in RR interval and stroke volume, cardiac output, or cardiac index in the overall population. A strong negative correlation was found between the left ventricular total isovolumic time and stroke volume, cardiac output, and cardiac index in all groups. Echocardiography-guided heart rate optimization results in a significant increase in cardiac output when compared with clinically derived pacing settings in the postoperative period. The optimal heart rate should be individualized for each patient, and total isovolumic time is the echocardiographic index with the highest sensitivity to determine the optimal hemodynamic profile.

Dyssynchrony and electromechanical delay are associated with focal fibrosis in the systemic right ventricle — Insights from echocardiography

BackgroundSystemic right ventricular (RV) dysfunction and sudden cardiac death remain problematic late after Mustard operation for transposition of the great arteries. The exact mechanism for that relationship is likely to be multifactorial including myocardial fibrosis. Doppler echocardiography gives further insights into the role of fibrosis shown by late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) in late morbidity. Methods and resultsTwenty-two consecutive patients, mean age 28±8years, were studied with 2D echocardiography, and also assessed by LGE CMR. The presence of LGE in 13/22 patients (59%) was related to delayed septal shortening and lengthening (P=0.002 &P=0.049), prolonged systemic RV isovolumic contraction time (P=0.024) and reduced systemic RV free wall and septal excursion (P=0.027 &P=0.005). The systemic RV total isovolumic time was prolonged but not related to extent of LGE. LGE extent was related to markers of electromechanical delay and dyssynchrony (delayed onset of RV free wall shortening and lengthening; r=0.73 &P=0.004 and r=0.62 &P=0.041, respectively, and QRS duration r=0.68, P<0.01) and was inversely related to systolic RV free wall shortening velocity (r=−0.59 &P=0.042). The presence of LGE was also related to lower exercise capacity, ≥mild tricuspid regurgitation and more arrhythmia (P=0.008, P=0.014 and P=0.040). RV free wall excursion and systolic tissue Doppler velocity were related to CMR derived RV ejection fraction (r=0.51, P=0.015, and r=0.77, P=<0.001, respectively). ConclusionPost Mustard repair, myocardial fibrosis is related to dyssynchrony, RV long axis dysfunction and tricuspid regurgitation. Echocardiographic measurements of systemic RV function can be confidently used in serial follow-up following Mustard operation.

Effect of Age on Left Ventricular Global Dyssynchrony in Asymptomatic Individuals: A Population Study.

Left ventricular (LV) segmental dyssynchrony is common in patients with heart failure or myocardial activation abnormalities and is associated with increased cardiovascular risk. Total isovolumic time (t-IVT) and Tei index are sensitive indexes of global ventricular dyssynchrony. The aim of this study was to investigate the effect of age on t-IVT and Tei index. We evaluated 410 individuals with no evidence for coronary heart disease or activation abnormalities. T-IVT was calculated as 60 - (total ejection time + total filling time) and Tei index as t-IVT/total ejection time. The relationship between age, LV systolic and diastolic function parameters as well as t-IVT and Tei index was studied. Ejection fraction and stroke volume did not change with age, whereas early diastolic filling velocity fell and atrial systolic velocity increased, reducing the E/A ratio. Isovolumic contraction time (IVCT) and isovolumic relaxation time (IVRT) lengthened. With every 10 years of age, total LV ejection time shortened by 1.5 sec/min and total filling time by 2.1 sec/min. T-IVT and Tei index increased with age and strongly correlated with IVCT and E/A, but not with ejection fraction or QRS duration. Normal aging is associated with worsening of LV global dyssynchrony shown by prolongation of isovolumic times resulting in shortening of filling and ejection times. Age also affects diastolic function as shown by E/A but not systolic function parameters, ejection fraction or stroke volume. Worsening of global dyssynchrony correlates with that of diastolic function but not with QRS duration.

Global dyssynchrony correlates with compromised left ventricular filling and stroke volume but not with ejection fraction or QRS duration in HFpEF

Background and Aim: Mechanical global left ventricular (LV) dyssynchrony reflected as prolonged total isovolumic time&lt;br /&gt;(t-IVT) has been introduced as a potential mechanism behind compromised stroke volume in heart failure (HF). It has also&lt;br /&gt;been shown to be superior to other markers of dyssynchrony in predicting response to cardiac resynchronization therapy&lt;br /&gt;(CRT), but its application in HF with preserved ejection fraction (HFpEF) remains unknown. The aim of this study was to&lt;br /&gt;assess the role of t-IVT in explaining symptoms in HFpEF.&lt;br /&gt;Methods: In 55 symptomatic HFpEF patients (age 60±9 years, NYHA class II-IV; LV EF ≥45%) and 24 age and gender&lt;br /&gt;matched controls, a complete Doppler echocardiographic study was performed including mitral annulus peak systolic&lt;br /&gt;excursion (MAPSE) and myocardial velocities as well as LV filling, outflow tract velocity time integral (VTI) and stroke volume&lt;br /&gt;measurements. Global LV dyssynchrony was assessed by t-IVT [in s/min; calculated as: 60 - (total ejection time + total filling&lt;br /&gt;time)], Tei index (t-IVT/ejection time) and pre-ejection time difference between LV and RV.&lt;br /&gt;Results: Patients had reduced lateral and septal MAPSE (p=0.009 and p=0.01, respectively) lower lateral and septal s’&lt;br /&gt;(p=0.002 and p=0.04, respectively) and e’ (p&amp;lt;0.001, for both) velocities and higher E/e’ ratio (p=0.01) compared to controls.&lt;br /&gt;They also had longer t-IVT (p&amp;lt;0.001), higher Tei index (p=0.04), but similar pre-ejection time difference and LVEF to controls.&lt;br /&gt;T-IVT correlated with LV filling time (r=0.44, p&amp;lt;0.001), stroke volume (r=-0.41; p=0.002), MAPSE (lateral: r=-0.36, p=0.007 and&lt;br /&gt;septal: r=-0.31; p=0.02), but not with LV mass index, LVEF, E/e’ ratio or QRS duration.&lt;br /&gt;Conclusion: Patients with HFpEF have exaggerated global mechanical dyssynchrony shown by prolonged t-IVT, compared&lt;br /&gt;with healthy age and gender matched controls. The relationship between t-IVT, LV filling and stroke volume suggests an&lt;br /&gt;association, more important than with ejection fraction or electrical dyssynchrony. These results support the importance of&lt;br /&gt;the individualistic approach for optimum HFpEF patient management.

Predictors of exercise capacity in heart failure

&lt;p&gt;Background and Aim: Compromised exercise capacity is a major symptom in patients with heart failure (HF) and reduced left ventricular (LV) ejection fraction (EF). Six-minute walk test (6-MWT) is popular for the objective assessment of exercise capacity in these patients but is largely confined to major heart centres. The aim of this study was to prospectively examine functional parameters that predict 6-MWT in patients with HF and reduced LVEF.&lt;/p&gt;&lt;p&gt;&lt;span&gt;Methods: &lt;/span&gt;In 111 HF patients (mean age 60Å}12 years, 56% male), a 6-MWT and an echo-Doppler study were performed in the same day. In addition to conventional ventricular function measurements, global LV dyssynchrony was indirectly assessed by total isovolumic time - t-IVT [in s/min; calculated as: 60 – (total ejection time – total filling time)], and Tei index (t-IVT/ejection time). Also, LV and right ventricular function were assessed by mitral and tricuspid annular plane systolic excursion (MAPSE and TAPSE, respectively). Based on the 6-MWT distance, patients were divided into 2 groups: Group I: ≤300m and Group II: &amp;gt;300m.&lt;/p&gt;&lt;p&gt;&lt;span&gt;Results: &lt;/span&gt;The 6-MWT distance correlated with t-IVT and Tei index (r=-0.37, p&amp;lt;0.001, for both), lateral and septal e’ velocities (r=0.41, p&amp;lt;0.001, and r=0.46, p&amp;lt;0.001, respectively), E/e’ ratio (r=-0.37, p&amp;lt;0.001) and TAPSE (r=0.45, p&amp;lt;0.001), but not with the other clinical or echo parameters. Group I patients had longer t-IVT, lower E/e’ratio, TAPSE and lateral e’ (p&amp;lt;0.001 for all) compared with Group II. In multivariate analysis, TAPSE [0.076 (0.017-0.335), p=0.001], E/e’ [1.165 (1.017-1.334), p=0.027], t-IVT [1.178 (1.014-1.370), p=0.033] independently predicted poor 6-MWT performance (&amp;lt;300m). Sensitivity and specificity for TAPSE ≤1.9 cm were 66% and 77%, (AUC 0.78, p&amp;lt;0.001); E/e’ ≥10.7 were 66% and 62% (AUC 0.67, p=0.002) and t-IVT ≥13 s/min were 64% and 60% (AUC 0.68, p=0.002) in predicting poor 6-MWT. Combined TAPSE and E/e’ had a sensitivity of 68% but specificity of 92% in predicting 6-MWT. Respective values for combined TAPSE and t-IVT were 71% and 85%.&lt;/p&gt;&lt;p&gt;&lt;span&gt;Conclusion: &lt;/span&gt;In patients with HF, the limited exercise capacity assessed by 6-MWT, is multifactorial being related both to the severity of right ventricular systolic dysfunction as well as to raised LV filling pressures and global dyssynchrony.&lt;/p&gt;

Left ventricular global dyssynchrony is exaggerated with age

&lt;p&gt;Background and Aim: Total isovolumic time (t-IVT) and Tei index both reflect global left ventricular (LV) dyssynchrony. They have been shown to be sensitive in responding to myocardial revascularization and in predicting clinical outcome in heart failure patients. Since most these patients are senior, determining the exact effect of age on such parameters remains mandatory. The aim of this study was to investigate the effect of age on LV t-IVT and Tei index compared with conventional systolic and diastolic parameters in normal individuals.&lt;/p&gt;&lt;p&gt;&lt;span&gt;Methods: &lt;/span&gt;We studied 47 healthy individuals, mean age 62+/-12 years (24 female), who were arbitrarily classified into three groups: M (middle age), S (seniors), and E (elderly), using spectral Doppler echocardiography and tissue-Doppler imaging. We studied the interrelation between age, LV systolic and diastolic function parameters as well as t-IV [60 – (total ejection time + total filling time) in s/min], and Tei index (T-IVT/ejection time).&lt;/p&gt;&lt;p&gt;&lt;span&gt;Results: &lt;/span&gt;LV ejection fraction was 68+/-6%, E/A ratio 1+/-0.4, filling time 538+/-136ms, ejection time 313+/-26ms, t-IVT 7.7+/-2.6 s/min and Tei index 0.41+/-0.14. Age strongly correlated with t-IVT (r=0.8, p&amp;lt;0.001) and with Tei index (r=0.7, p&amp;lt;0.001) but not with QRS duration. Age also correlated with E/A ratio (r=-0.6, p&amp;lt;0.001), but not with global or segmental systolic function measurements. Mean values for t-IVT were 5.5 (95% CI, 4.6-6.3 s/min) for M, 6.9 (95% CI, 6.0-7.8 s/min) for S and 9.5 (95% CI, 8.4-10.6 s/min) for E groups. The corresponding upper limit of the t-IVT 95% normal CI (calculated as mean +/-2SD) for the three groups was 8.3 s/min, 10.5 s/min and 14.5 s/min, respectively. The upper limit of normal t-IVT 95% CI was significantly shorter in the S compared with the E group (p=0.001). T-IVT correlated with A wave (r=0.66, p&amp;lt;0.001), E/A ratio (r=-0.56, p&amp;lt;0.001), septal e’ (r=-0.49, p=0.001) and septal a’ (r=0.4, p=0.006), but not with QRS.&lt;/p&gt;&lt;p&gt;&lt;span&gt;Conclusion: &lt;/span&gt;In normals, age is associated with exaggerated LV global dyssynchrony and diastolic function disturbances, but systolic function remains unaffected. The strong relationship between age and t-IVT supports its potential use as a marker of global LV dyssynchrony. In addition, variations in the upper limit of normal values, particularly in the elderly may have significant clinical applications in patients recommended for CRT treatment.&lt;/p&gt;