Diastolic Intraventricular Pressure Gradients Research Articles

Non-invasive assessment of left ventricular relaxation property using color M-mode-derived intraventricular pressure gradients in cats

IntroductionDiastolic dysfunction is an early clinical feature of feline hypertrophic cardiomyopathy (HCM). The left ventricular filling in early diastole is facilitated by the diastolic intraventricular pressure gradient (IVPG). The study objectives were to evaluate color Doppler M-mode-derived IVPG calculation in cats as a non-invasive assessment of the left ventricular relaxation property to determine the normal ranges of peak IVPG in cats and investigate the influence of left ventricular function and heart rate (HR). AnimalsOne hundred and six client-owned apparently healthy cats. MethodsProspective cross-sectional study. Quantitative analysis of color Doppler M-mode images was used to estimate total and segmental IVPGs non-invasively. ResultsThe total IVPG was 0.76 mmHg (95% reference interval (RI): 0.28–1.29 mmHg), the basal IVPG 0.34 mmHg (95% RI: 0.07–0.63 mmHg), and the mid-apical IVPG 0.42 mmHg (95% RI: 0.15–0.71 mmHg). Total and segmental IVPG increased with HR (P < 0.003), while segmental percent IVPG was HR independent. A short isovolumic relaxation time (IVRT) and a high mitral annular velocity in early diastole were associated with an increase in total IVPG (P = 0.008 and P = 0.009, respectively) adjusted for HR. An increase in IVPG was associated with an increase in mitral inflow velocity (P < 0.001). ConclusionsFeline IVPGs increase with HR and a short IVRT, which was believed to be a normal physiologic adrenergic response associated with an increased sympathetic tone. Future studies of segmental IVPG changes in feline HCM are needed to evaluate the clinical applicability of color Doppler M-mode estimated IVPGs in feline cardiology.

Noninvasive estimation of impaired left ventricular untwisting velocity by peak early diastolic intra-ventricular pressure gradients using vector flow mapping.

Introduction of vector flow mapping (VFM) based on the combination of color Doppler and speckle-tracking echocardiography provides noninvasive assessment of early diastolic intra-ventricular pressure gradient (ED-IVPG). The purpose of this study was to evaluate the value of peak ED-IVPG measurement just after aortic valve closure using VFM for noninvasive estimation of impaired LV untwisting velocity as the index of LV relaxation in the clinical setting. The study included 65 consecutive patients in whom echocardiography was performed for the assessment of LV function. We assessed peak ED-IVPG between LV apex and base by VFM analysis software. We also measured peak LV untwisting velocity and LV twisting by speckle-tracking strain analysis. Peak ED-IVPG was successfully and quickly assessed in all the study patients. Peak ED-IVPG was significantly reduced in patients with impaired peak LV untwisting velocity (< 70 degrees/s) compared with patients without impaired peak LV untwisting velocity. The receiver operating characteristic analysis showed the best cut-off value of peak ED-IVPG for determining impaired peak LV untwisting velocity was 0.40mmHg (sensitivity 81%, specificity 74%, and area under the curve 0.81). There was a well correlation between peak ED-IVPG and peak LV untwisting velocity (r = 0.64, p < 0.0001). The present results suggest that peak ED-IVPG just after aortic valve closure measured by VFM may be used as noninvasive index for estimation of impaired LV untwisting velocity in the clinical setting.

Effects of Individual and Coexisting Diabetes and Cardiomyopathy on Diastolic Function in Rats (Rattus norvegicus domestica).

The goal of this study was to evaluate diastolic intraventricular pressure gradients (IVPG) and 2-dimensional tissue tracking (2DTT) patterns during diabetes and cardiomyopathy. Rats (n = 60) were induced to become diabetic (DM group, n = 15) by using streptozotocin, to become cardiomyopathic (CM group, n = 15) by using isoproterenol, and to become both diabetic and cardiomyopathic (DMCM group, n = 15); control rats (CT group, n = 15) were injected with saline. Two months after induction, all rats underwent conventional echocardiography, IVPG, and 2DTT and then were euthanized for microscopic examination of cardiac fibrosis. Compared with the controls, all 3 treated groups showed diastolic dysfunction and delayed cardiac relaxation. DMCM rats showed the most pronounced cardiac abnormalities. In addition, CM and DMCM groups had showed decreased middle IVPG, whereas DMCM rats had decreased midapical IVPG. Although the overall IVPG of the CM group was normal, the middle segment was significantly decreased. 2DTT results showed that the DMCM group had a delay in relaxation compared with other groups. IVPG and 2DTT can be used to overcome the limitation of conventional echocardiographic methods and reveal diastolic dysfunction. DM worsened diastolic function during cardiac disease.

Analysis of inter-system variability of systolic and diastolic intraventricular pressure gradients derived from color Doppler M-mode echocardiography

Assessment of intraventricular pressure gradients (IVPG) using color Doppler M-mode echocardiography has gained increasing interest in the evaluation of cardiac function. However, standardized analysis tools for IVPG quantification are missing. We aimed to evaluate the feasibility, the test-retest observer reproducibility, and the inter-system variability of a semi-automated IVPG quantification algorithm. The study included forty healthy volunteers (50% were men). All volunteers were examined using two ultrasound systems, the Philips Epiq 7 and the General Electric Vivid 6. Left ventricular diastolic (DIVPG) and systolic (SIVPG) intraventricular pressure gradients were measured from the spatiotemporal distribution of intraventricular propagation flow velocities using color Doppler M-mode in standard apical views. There was good feasibility for both systolic and diastolic IVPG measurements (82.5% and 85%, respectively). Intra and inter-observer test-retest variability measured with the intraclass correlation coefficient were 0.98 and 0.93 for DIVPG respectively, and 0.95 and 0.89 for SIVPG respectively. The inter-system concordance was weak to moderate with Lin’s concordance correlation coefficient of 0.59 for DIVPG and 0.25 for SIVPG. In conclusion, it is feasible and reproducible to assess systolic and diastolic IVPG using color Doppler M-mode in healthy volunteers. However, the inter-system variability in IVPG analysis needs to be taken into account, especially when using displayed data.

Echocardiographic evidence of left ventricular untwisting-filling interplay

BackgroundLeft ventricular untwisting generates an early diastolic intraventricular pressure gradient (DIVPG) than can be quantified by echocardiography. We sought to confirm the quantitative relationship between peak untwisting rate and peak DIVPG in a large adult population.MethodsFrom our echocardiographic database, we retrieved all the echocardiograms with a normal left ventricular ejection fraction, for whom color Doppler M-Mode interrogation of mitral inflow was available, and left ventricular untwisting rate was measurable using speckle tracking. Standard indices of left ventricular early diastolic function were assessed by Doppler (peaks E, e’ and Vp) and speckle tracking (peak strain rate Esr). Load dependency of DIVPG and untwisting rate was evaluated using a passive leg raising maneuver.ResultsWe included 154 subjects, aged between 18 to 77 years old, 63% were male. Test-retest reliability for color Doppler-derived DIVPG measurements was good, the intraclass correlation coefficients were 0.97 [0.91–0.99] and 0.97 [0.67–0.99] for intra- and inter-observer reproducibility, respectively. Peak DIVPG was positively correlated with peak untwisting rate (r = 0.73, P < 0.001). On multivariate analysis, peak DIVPG was the only diastolic parameter that was independently associated with untwisting rate. Age and gender were the clinical predictive factors for peak untwisting rate, whereas only age was independently associated with peak DIVPG. Untwisting rate and DIVPG were both load-dependent, without affecting their relationship.ConclusionsColor Doppler-derived peak DIVPG was quantitatively and independently associated with peak untwisting rate. It thus provides a reliable flow-based index of early left ventricular diastolic function.

P3365Relationship between early diastolic intra-ventricular pressure gradient shortly after aortic valve closure estimated by vector flow mapping and left ventricular diastolic untwisting rate in humans

Abstract Background Early diastolic suction is an important determinant of early diastolic function. Previous studies using color Doppler M-mode and speckle-tracking echocardiography have shown left ventricular (LV) early diastolic LV untwisting rate is directly related to LV intra-ventricular pressure gradient (IVPG) between LV base and apex during early diastole. Recent introduction of vector flow mapping (VFM) using combination of color Doppler and speckle-tracking echocardiography provides noninvasive and feasible assessment of early diastolic IVPG shortly after aortic valve closure including isovolmic relaxation period (ED-IVPG) in humans. However, relationship between VFM–derived ED-IVPG and early diastolic LV untwisting rate has not been well investigated. Purpose The purpose of this study was to examine relationship between ED-IVPG estimated by VFM and LV untwisting rate by speckle-tracking echocardiography. Methods The study population consists of 66 patients without segmental wall motion abnormality, significant valvular diseases, and atrial fibrillation who underwent echocardiography for evaluation of LV function (age: 60±15 years, LVEF: 49±16%). From the apical long-axis views by color Doppler echocardiography, we analyzed peak ED-IVPG between LV base and apex just after aortic valve closure (figure) using commercially available VFM analysis software (DAS-RS1, Hitachi). We assessed peak early diastolic LV untwisting rate and LV torsion from LV basal and apical short-axis view by speckle-tracking echocardiography. We evaluated correlation between ED-IVPG and LV untwisting rate. We also evaluated correlation between ED-IVPG and peak systolic LV torsion, LV end-diastolic (EDV) and end-systolic volumes (ESV), ejection fraction (EF), early diastolic velocity (E) of LV inflow, average early diastolic velocity (e') of mitral annulus, and average E/e'. Results In all the study patients, ED-IVPG was successfully and quickly evaluated. 1) ED-IVPG correlated well with peak LV untwisting rate (r=0.64, p&lt;0.0001). 2) ED-IVPG significantly correlated with LV torsion, LVEDV, LVESV, and LVEF (r=0.47, r=−0.48, r=−0.46, and r=0.48, respectively, p&lt;0.001). 3) There were no significant correlations between ED-IVPG and other indexes including E, average e', and average E/e'. According to receiver operating characteristic analysis, the best cut-off value of ED-IVPG for determining impaired LV untwisting rate (&lt;80 degrees/s) was found at 0.42 mmHg (sensitivity 81%, specificity 76%, and area under the curve 0.86) ED-IVPG measurement by VFM Conclusions The present results showed that noninvasive VFM-derived peak ED-IVPG shortly after aortic valve closure is related to early diastolic peak LV untwisting rate. ED-IVPG easily and quickly estimated by VFM may be used as an additional index for LV diastolic function.

Assessment of early diastolic intraventricular pressure gradient in the left ventricle among patients with repaired tetralogy of Fallot

Assessment of left ventricular (LV) dysfunction is vital in patients with repaired tetralogy of Fallot (rTOF). The early diastolic intraventricular pressure gradient (IVPG) in the LV plays an important role in diastolic function. IVPG is calculated as the intraventricular pressure difference divided by the LV length, which allows to account for differences in LV size and therefore calculate IVPG in children. We aimed to investigate the mechanisms of LV diastolic dysfunction by measuring mid-to-apical IVPG as an indicator of the active suction force sucking blood from the left atrium into the LV. We included 38 rTOF patients and 101 healthy controls. The study population was stratified based on age group into children (4-9years), adolescents (10-15years), and adults (16-40years). IVPGs were calculated based on mitral inflow measurements obtained using color M-mode Doppler echocardiography. Although total IVPGs did not differ between rTOF patients and controls, mid-to-apical IVPGs in adolescents and adults were smaller among rTOF patients than among controls (0.15±0.05 vs. 0.21±0.06mmHg/cm, p<0.05; 0.09±0.07 vs. 0.17±0.05mmHg/cm, p<0.001; respectively). Additionally, only mid-to-apical IVPG correlated linearly with peak circumferential strain (ρ=0.217, p=0.011), longitudinal strain (ρ=-0.231, p=0.006), torsion (ρ=-0.200, p=0.018), and untwisting rate in early diastole (ρ=-0.233, p=0.006). In rTOF, the mechanisms underlying diastolic dysfunction involve reduced active suction force, which correlates with reduced LV deformation in all directions.

MRI Assessment of Diastolic and Systolic Intraventricular Pressure Gradients in Heart Failure

A deep phenotypic characterization of heart failure (HF) is important for a better understanding of its pathophysiology. In particular, novel noninvasive techniques for the characterization of functional abnormalities in HF with preserved ejection fraction are currently needed. While echocardiography is widely used to assess ventricular function, standard echocardiographic techniques provide a limited understanding of ventricular filling. The application of fluid dynamics theory, along with assessments of flow velocity fields in multiple dimensions in the ventricle, can be used to assess intraventricular pressure gradients (IVPGs), which in turn may provide valuable insights into ventricular diastolic and systolic function. Advances in imaging techniques now allow for accurate estimations of systolic and diastolic IVPGs, using noninvasive methods that are easily applicable in clinical research. In this review, we describe the basic concepts regarding intraventricular flow measurements and the derivation of IVPGs. We also review existing literature exploring the role of IVPGs in HF.

0157: Echo-based diastolic intraventricular pressure difference as a surrogate of left ventricular untwisting

Left ventricular (LV) early diastolic filling is related to an active process of LV relaxation, caused by its rapid untwisting. The untwisting rate (UR) has been reported to be a robust marker of diastolic function but is technically hard to assess in practice. The untwisting phenomenon generates a diastolic intraventricular pressure gradient (IVPGd), which can be assessed by colour Doppler M-Mode. Previous studies showed a close temporal relation between the UR and the IVPGd peaks, but the relation between their magnitudes as well as their load dependency remain unclear. We developed our own Matlab software for IVPGd assessment by colour Doppler M-Mode based on Bernoulli equation. From our research database, we retrieved all echocardiograms where ejection fraction was normal, the colour M-Mode tracing was available and UR was measurable using speckle tracking. Passive leg raising was used in 19 healthy volunteers to study the impact of preload on the IVPGd measurement. We included 104 echocardiograms (83% males, median age 23y [19-69]). The median peak IVPGd was 3.1mmHg [1.6-7.8] and correlated to the peak UR (r=0.57, P<0.0001, figure). There was also a significant correlation between the IVGPd peak and E’ (r=0.62, P<0.0001). For peak IVPGd, correlations between inter- and intra-observer measures were calculated on 10 randomly selected subjects and were 0.83 and 0.99 (P<0.05). Compared to UR and E’, IVPGd was also significantly increased with leg lifting (2.7±0.8mmHg vs 3.3±0.8mmHg, P<0.001). Peak IVPGd based on colour Doppler M mode echocardiography is positively correlated to the LV UR. Despite the observation that IVPGd is not less load-dependent than other parameters, it requires only an echo loop easily obtained during routine clinical studies and is highly reproducible using a semi-automatic software algorithm. This new tool could easily become a new practical echo index for diastolic function assessment. Abstract 0157 - Figure

Does the Intraventricular Pressure Gradient Increase following Acute High Intensity Interval Exercise in Heart Failure?

An increase in the diastolic intraventricular pressure gradient (IVPG) is an important mechanism that aids in left ventricular filling during exercise. Prior work has shown that individuals with severe heart failure have impairment in IVPG at peak exercise (Am J Physiol Heart Circ Physiol 2005; 289: H2081-H2088). We have previously shown in the present study cohort (J Appl Physiol 2011; 110: 398-406) that left ventricular peak twist reserve is blunted, but that left ventricular peak untwisting rate, due to an increase in peak basal rotation rate and not peak apical rotation rate, is enhanced following acute high intensity interval (HIT) exercise in patients with mild heart failure. It is unclear whether regional differences in rotational properties of the ventricle in heart failure (i.e., base versus apex) that we have observed affect the IVPG post-HIT. PURPOSE: To determine if the IVPG immediately following acute HIT would be increased despite impaired apical contribution to left ventricular untwisting. METHODS: Nine patients (49 ± 16 years; 6 male) with mild heart failure (NYHA Class I/II = 7/2; left ventricular ejection fraction = 36 ± 7%; peak VO2 = 27 ± 9 ml/kg/min) performed 1 session of HIT (4 × 4 min at 96 ± 10% peak heart rate with a 3 min recovery period between bouts). Cardiac MRI (1.5 T scanner) was performed at rest prior to HIT and 6 ± 2 min following HIT. Rotational mechanics and IVPG were analyzed using in-house techniques with custom software. Analyses were performed using 2-tailed paired t-testing with p<0.05 being significant. RESULTS: Our novel finding is that the IVPG from pre-HIT (1.8 ± 1.0 mmHg) to post-HIT (1.6 ± 0.7 mmHg) remained effectively unchanged (p>0.05), despite a significant 24% increase in untwisting rate (p<0.05) that was modulated primarily by an increase in peak basal and not peak apical rotation rate. CONCLUSION: The maintenance of, but not the increase in, IVPG may aid in diastolic filling following HIT in patients with mild heart failure. Impairment in apical rotational mechanics likely account for the poor IVPG reserve of the left ventricle in mild heart failure.

Effect of organic nitrates on intraventricular pressure gradients in heart failure patients with preserved ejection fraction

Introduction. Patients with Heart Failure (HF) and preserved ejection fraction (HFpEF) show high mortality, yet not all its causes are fully understood. The aim of this study was to assess the hemodynamic response in HFpEF patients to an acute dose of sublingual nitro-glycerine (SL-NTG) during chronic vasodilator therapy. Methods. Colour M-mode Doppler (CMM) is a non-invasive ultrasound technique used to obtain left ventricular (LV) blood flow velocities during early filling and to calculate intra ventricular pressure gradients (IVPG). CMM recordings of 20 patients (HFpEF) during pre and post SL-NTG were obtained and processed with a specific algorithm to extract an IVPG map and related parameters. Average values from the available files were calculated and a Wilconox test was performed to compare the values during pre and post therapy, assuming a difference of p<0.05 as significant and of p<0.001 as highly significant. Results. The most relevant parameters identified as significantly different for pre and post treatment were reversal (p=0.03) and late (p=0.03) diastolic IVPG, E-wave velocity (p=0.003) and heart rate (HR)(p=0.02). Conclusion. Results are in accordance to the expecting effects for an acute SL-NTG dose: an increase in HR and myocardial contractility (late diastolic IVPG is directly related to atrial contraction) and a decrease in peak E-wave velocity, supporting the possible use of CMM technique as a follow up tool in the research of a more effective therapy for the HFpEF pathology.

Intraventricular Pressure Gradients in Heart Failure

The aim of the present study was to characterize intraventricular pressure gradients (IVPGs) in an animal model of chronic heart failure. New Zealand rabbits were treated with doxorubicin (heart failure group, n=5) or saline (control group, n=5) and instrumented with pressure catheters placed in the apex and outflow-tract of left ventricle (LV) and with sonomicrometer crystals placed in the apex and base of the LV free wall. In heart failure animals, ventricular filling was delayed and slower when compared with control animals. Moreover, the physiological nonuniformity observed between apical and basal segments in normal hearts was abolished in failing hearts. Simultaneously, physiological IVPGs observed during normal ventricular filling were entirely lost in heart failure animals. During ventricular emptying physiological nonuniformity between apical and basal segments observed in control animals was also abolished in heart failure animals. In failing hearts minimal length occurred later and almost at same time both in apical and in basal myocardial segments. Simultaneously, the characteristic IVPG pattern observed in healthy hearts during systole, which promotes ventricular emptying, was not observed in failing hearts. The present study showed that diastolic IVPGs, a marker of normal ventricular filling, and systolic IVPGs, a marker of normal ventricular emptying, are abolished in heart failure.

Intraventricular pressure gradients: the often ignored question of how and why does the ventricle suck

Intraventricular pressure gradients: the often ignored question of how and why does the ventricle suck

Left intraventricular diastolic and systolic pressure gradients

To describe left ventricular (LV) function comprehensively, it is crucial to characterize precisely transmitral, intraventricular and transaortic pressure-flow relations. The site of measurement is important; as the measurement location is moved from the mitral valve toward the apex and the outflow tract, important regional pressure differences are recorded inside the LV. These intraventricular pressure gradients (IVPGs) play an important role in ventricular filling in the normal heart and may be abolished by systolic or diastolic dysfunction. Despite their apparent importance in ventricular filling and diastolic function, IVPGs have never been utilized in clinical cardiology, due to the complexity of their acquisition. The application of Doppler echocardiography allows the reconstruction of diastolic IVPGs completely non-invasively, thus avoiding the risk and expense of a cardiac catheterization. Regional pressure gradients are also present during ventricular emptying but their correlation with systolic function is not so clear. The current minireview highlights theories and experimental data on invasive and non-invasive assessment of diastolic and systolic IVPGs and their role in LV filling and emptying. We also review the pathophysiological modulation of regional gradients, their importance in understanding and evaluating the complex phenomena underlying ventricular filling, as well as their potential clinical application.

Evaluation of LV Diastolic Function From Color M-Mode Echocardiography

this study evaluated early diastolic filling dynamics using a semiautomated objective analysis of filling velocities obtained from color M-mode echocardiography. diastolic function can be evaluated from color M-mode echocardiography by measuring the early diastolic flow propagation velocity (Vp) from the slope of a single linear approximation of an isovelocity contour. However, this method has limitations and may not accurately represent diastolic filling. we used a semiautomated objective analysis of color M-mode echocardiograms from a development cohort of 125 patients with varying diastolic function to quantify left ventricular filling velocities. Early diastolic filling was not accurately described with a single propagation velocity; instead, the rapid initial filling velocity abruptly decelerated to a slower terminal velocity. Then, we evaluated a new measure of diastolic function in a separate group of 160 patients. compared with normal filling, diastolic dysfunction with restricted filling had a lower initial velocity (53 ± 21 cm/s vs. 87 ± 29 cm/s, p < 0.001), and the deceleration point occurred closer to the mitral annulus (2.4 ± 0.6 cm vs. 3.1 ± 0.7 cm, p < 0.05). The product of the initial velocity and the distance to the deceleration point from the mitral annulus, indicating the strength of the early filling (Vs), was progressively reduced with diastolic dysfunction. In a separate validation cohort of 160 patients, Vs better recognized diastolic dysfunction (classified by reduced diastolic intraventricular pressure gradient, elevated pulmonary capillary wedge pressure, or elevated B-type natriuretic peptide) than Vp did. early diastolic flow propagation occurs with an initial rapid velocity that abruptly decelerates to a terminal velocity. With diastolic dysfunction, the initial velocity is slower and the deceleration point occurs closer to the mitral annulus than with normal filling. A new parameter that combines these 2 effects (Vs) provides a more accurate assessment of diastolic function than the conventional propagation velocity.

Comments on Point:Counterpoint: Left ventricular volume during diastasis is/is not the physiological in vivo equilibrium volume and is/is not related to diastolic suction

Comments on Point:Counterpoint: Left ventricular volume during diastasis is/is not the physiological in vivo equilibrium volume and is/is not related to diastolic suction

Echocardiographic Evaluation of Diastolic Function Can Be Used to Guide Clinical Care

For normal cardiac performance, the left ventricle (LV) must be able to eject an adequate stroke volume at arterial pressure (systolic function) and fill without requiring an elevated left atrial (LA) pressure (diastolic function). These systolic and diastolic functions must be adequate to meet the needs of the body both at rest and during stress. Response by Tschope and Paulus on p 809 Systolic function is conveniently (although not always accurately) measured as the ejection fraction (EF), calculated as stroke volume divided by end-diastolic volume.1 The LV EF is easily interpreted. The lower limit of normal is ≈50%. The lower the EF is, the greater the reduction in systolic function. Diastolic function has been more difficult to evaluate.2 Traditionally, invasive measures of LV diastolic pressure-volume relations and the rate of LV pressure fall during isovolumetric relaxation have been used. However, these methods are not practical for routine clinical use and do not adequately evaluate all aspects of diastolic filling.3 Comprehensive echocardiographic evaluation of the dynamics of LV filling using blood pool and tissue Doppler has now progressed so that it provides clinically important information that can be used to direct patient care. We present data that support the use of echocardiographic evaluation of diastolic function to recognize cardiac dysfunction in patients with heart failure, especially those with preserved EF; to guide the management of patients by identifying those with and without elevated left filling pressures regardless of underlying EF; and to determine prognosis in a wide variety of patient populations. Although the LV end-diastolic pressure-volume relation describes the passive properties of the LV, LV filling is not a passive or slow process.3 In fact, the peak flow rate across the mitral valve is equal to or greater than the peak flow rate across the aortic valve. …

Relationship Between Ventricular Contractility and Early Diastolic Intraventricular Pressure Gradients: A Diastolic Link to Systolic Function

Early diastolic intraventricular pressure gradient (IVPG), as derived by color M-mode echocardiography, has been proposed to correlate with left ventricular (LV) elastic recoil. However, any relationship to quantifiable indices of LV contractility is poorly defined. To relate IVPG with invasive and noninvasive indices of contractility, 6 closed-chest dogs each had a high-fidelity conductance catheter placed into the LV for continuous determination of end-diastolic pressures, volumes, +dP/dt(max), and the time constant of LV relaxation (tau) under baseline conditions and 4 different stages of beta-receptor modulation. At each stage, IVPGs were determined from color M-mode echocardiography images. Doppler-derived strain rate (epsilon') and myocardial systolic myocardial velocities (S(m)) were also measured. E(max) was obtained from the slope of the end-systolic pressure-volume relationship during caval occlusion. Results of contractility indices were compared to IVPG with regression analysis. IVPG ranged from 0.72 to 3.95 mm Hg whereas E(max) ranged from 0.66 to 14.9 mm Hg/mL and end-systolic volume ranged from 1.9 to 59.7 mL. IVPG correlated with epsilon' (r = 0.71), S(m) (r = 0.67), end-systolic volume (r = 0.53), and invasive indices (+dP/dt(max), r = 0.71, and E(max), r = 0.82). Early diastolic IVPGs are associated with LV contractility. These findings may explain the proposed mechanism in which potential energy stored during systole is released during diastole to provide for adequate ventricular filling, even under low filling pressures.

Role of Tissue Doppler and Color M‐Mode Imaging for Evaluation of Diastolic Function in Ambulatory Patients with LV Systolic Dysfunction

Tissue Doppler imaging (TDI) and color M-mode (CMM) indices provide assessment of left ventricular (LV) relaxation when combined with pulse-wave Doppler (PWD)-derived transmitral inflow, allows for estimation of LV filling pressures. However, use of these indices in patients with LV systolic dysfunction (LVSD) has not been well characterized. The study included 115 patients (age 58 +/- 11 years, 67% male) with LVSD (LV ejection fraction [LVEF] < 55%). Patients were grouped according to the diastolic LV filling pressure assessed by E/Em(septal) ratio as follows: 1) Normal (NFP), E/Em(septal) < 8; 2) Intermediate (IFP), E/Em(septal): 8-15; and 3) High (HFP), E/Em(septal) >15. Age-, gender-, and LVEF-adjusted analyses were performed. LV volumes and LVEF were significantly different between the groups (P < 0.01). PWD-derived E-wave velocity showed a significant stepwise increase across the three groups and the Em(septal) velocity demonstrated a stepwise decrease (P < 0.01 for both). CMM-derived diastolic intra-ventricular pressure gradient (IVPG) was significantly lower in the HFP compared to the other 2 groups (P < 0.01 for both); Vp was increased in the HFP compared to the other 2 groups (P < 0.01 for both), and Vp exhibited a U-shape relationship to LVEF. In patients with LVSD, abnormal LV relaxation is uniformly observed regardless of LV filling pressure. PWD-derived E-wave velocity and the TDI-derived Em velocity are important measurements to identify elevated LV filling pressures. CMM-derived Vp and IVPG were of limited incremental value for the evaluation of diastolic function in patients with LVSD.

Issue Highlights

HomeCirculationVol. 113, No. 21Issue Highlights Free AccessIn BriefPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessIn BriefPDF/EPUBIssue Highlights Originally published30 May 2006https://doi.org/10.1161/circ.113.21.2473Circulation. 2006;113:2473IMPACT OF TRANSFORMING GROWTH FACTOR-β1 ON ATRIOVENTRICULAR NODE CONDUCTION MODIFICATION BY INJECTED AUTOLOGOUS FIBROBLASTS IN THE CANINE HEART, by Bunch et al.Pharmacological treatment of atrial fibrillation using antiarrhythmic agents or ventricular rate control is challenging because of variable success and medication side effects. Catheter ablation also is not 100% successful and carries the risk of procedural complications. In this issue of Circulation, Bunch and colleagues describe a technique of percutaneously injecting cultured fibroblasts from skin biopsies to modulate atrioventricular (AV) nodal conduction and rate control in a canine model. Using electroanatomic mapping and intracardiac echocardiography to guide delivery, they injected fibroblasts (with or without transforming growth factor-β1) through a NOGA catheter at several AV nodal input regions. Regulation of AV nodal conduction and ventricular rate reduction during induced atrial fibrillation was observed and was more pronounced in dogs receiving transforming growth factor-β1–treated fibroblast injections. There were no major complications or long-term high-grade AV block. Local cell delivery may eventually be a potential therapeutic option, perhaps combined with medication and/or device therapy to modulate ventricular rate control during atrial arrhythmias. See p 2485 (and editorial on p 2474).ENHANCED VENTRICULAR UNTWISTING DURING EXERCISE: A MECHANISTIC MANIFESTATION OF ELASTIC RECOIL DESCRIBED BY DOPPLER TISSUE IMAGING, by Notomi et al.Classical concepts of myocardial function learned by all cardiologists center around pressure-volume relationships in the right and left ventricles. It is important to realize, however, that the sequence and pattern of contraction of the 2 ventricles is different: The right ventricle contracts more like a bellows, but the left ventricle undergoes a complex cycle of twisting and untwisting in systole and diastole. Notomi et al provide a detailed analysis of left ventricular (LV) untwisting both at rest and during exercise using Doppler tissue imaging. Although healthy volunteers enhance the rate of untwisting during exercise, thus increasing the diastolic intraventricular pressure gradient (facilitating LV “suction”), patients with hypertrophic cardiomyopathy have a blunted untwisting response to exercise. The new insights into the dynamic relationship between LV systolic and diastolic function described in this paper offer new tools for evaluating diastolic LV function in a variety of cardiovascular disease states and potentially monitoring the response to therapy. See p 2524.PERCUTANEOUS TREATMENT WITH DRUG-ELUTING STENT IMPLANTATION VERSUS BYPASS SURGERY FOR UNPROTECTED LEFT MAIN STENOSIS: A SINGLE-CENTER EXPERIENCE, by Chieffo et al.Coronary artery bypass grafting (CABG) is the preferred revascularization strategy for left main coronary artery (LMCA) disease. Improvements in results with percutaneous coronary intervention (PCI) with drug-eluting stents (DES) have led interventional cardiologists to perform unprotected LMCA procedures. Clinical trial evidence supporting such an approach is lacking, however. In this issue of Circulation, Chieffo et al report the single-center retrospective experience in patients with LMCA stenosis treated with PCI and DES (n=107) or CABG (n=142). At 1 year, there was no difference in the degree of protection against death, stroke, myocardial infarction, and revascularization between PCI with DES and CABG for LMCA disease. These results support the need for randomized trials with longer clinical follow-up to define optimal revascularization strategies for LMCA disease. See p 2542.Visit http://circ.ahajournals.org:Images in Cardiovascular MedicineUntreated 37-Year-Old Homozygous Familial Hypercholesterolemic Smoker. See p e777.Near Sudden Death From Cardiac Lipoma in an Adolescent. See p e778.Left Ventricular Pseudoaneurysm: A Late Complication of Low-Energy DC Ablation. See p e780. Download figureDownload PowerPointCorrespondenceSee p e782. Previous Back to top Next FiguresReferencesRelatedDetails May 30, 2006Vol 113, Issue 21 Advertisement Article InformationMetrics https://doi.org/10.1161/circ.113.21.2473 Originally publishedMay 30, 2006 PDF download Advertisement