Alteration of left ventricular diastolic function during coronary angioplasty-induced ischemia: a color M-mode Doppler study

Invasive and noninvasive assessment of exercise-induced ischemic diastolic response using pressure transducers

Left ventricular (LV) pressure curve shows early high-magnitude changes in the presence of induced ischemia. A dramatic rise in LV and left atrial end-diastolic pressures occurs within seconds to minutes in the presence of ischemia induced by dynamic or handgrip exercise as well as pacing of 38 to 183% and during short coronary balloon occlusion of 32 to 208% of baseline. Changes in relaxation or volumetric filling rate or ejection fraction were significantly less pronounced.

Similar end-diastolic abnormalities occurring mainly in patients with coronary artery disease (CAD) have been shown in noninvasive recordings obtained by pressure transducer placed over the point of maximal LV beat (pressocardiograms). Specifically, the amplitude of the A wave to total excursion of pressocardiogram showed a similar high-magnitude increase after dynamic or handgrip exercise in average by 60 to 142% of baseline; however, changes in pressocardiographic relaxation time indexes were only slightly abnormal. A well-defined “ischemic pattern” of pressocardiographic diastolic changes with handgrip, showed a high prevalence in CAD patients.

The assessment of diastolic changes in the presence of handgrip-inducible ischemia using noninvasive pressure transducers might provide after further studies a simple complementary diagnostic tool to assist in identification of patients with atypical or asymptomatic CAD.

Wave propagation of myocardial stretch: correlation with myocardial stiffness

The mechanism of flow propagation during diastole in the left ventricle (LV) has been well described. Little is known about the associated waves propagating along the heart walls. These waves may have a mechanism similar to pulse wave propagation in arteries. The major goal of the study was to evaluate the effect of myocardial stiffness and preload on this wave transmission. Longitudinal late diastolic deformation and wave speed (Vp) of myocardial stretch in the anterior LV wall were measured using sonomicrometry in 16 pigs. Animals with normal and altered myocardial stiffness (acute myocardial infarction) were studied with and without preload alterations. Elastic modulus estimated from Vp (E VP; Moens-Korteweg equation) was compared to incremental elastic modulus obtained from exponential end-diastolic stress-strain relation (E SS). Myocardial distensibility and α- and β-coefficients of stress-strain relations were calculated. Vp was higher at reperfusion compared to baseline (2.6 ± 1.3 vs. 1.3 ± 0.4 m/s; p = 0.005) and best correlated with E SS (r2 = 0.80, p < 0.0001), β-coefficient (r2 = 0.78, p < 0.0001), distensibility (r2 = 0.47, p = 0.005), and wall thickness/diameter ratio (r2 = 0.42, p = 0.009). Elastic moduli (E VP and E SS) were strongly correlated (r2 = 0.83, p < 0.0001). Increasing preload increased Vp and E VP and decreased distensibility. At multivariate analysis, E SS, wall thickness, and end-diastolic and systolic LV pressures were independent predictors of Vp (r2 model = 0.83, p < 0.0001). In conclusion, the main determinants of wave propagation of longitudinal myocardial stretch were myocardial stiffness and LV geometry and pressure. This local wave speed could potentially be measured noninvasively by echocardiography.

Perioperative Diastolic Dysfunction

Left ventricular diastolic dysfunction (LVDD) has only recently been recognized as an important determinant of perioperative morbidity. Intraoperative echocardiographers have been slow to adopt assessment of LVDD into clinical practice. This has been partly attributable to the complex measurements required to characterize LVDD, which are in turn related to how our understanding of diastole has evolved. Additionally, the lack of effective therapeutic options has left many wondering whether it is worthwhile to characterize this pathology in the first place. However, therapies are developed more rapidly once a problem can be identified reliably. The assessment of LVDD is centered on how effectively the left ventricle can fill. Diastolic dysfunction affects intraventricular pressures and stiffness, which in turn affect the pressure relationship between the left atrium and the left ventricle thereby affecting transmitral flow. Since echocardiography can enable the measurement of flow velocities, transmitral diastolic filling flow patterns provide robust information on diastolic function. The impact of abnormal diastolic function on left atrial pressure has consequences for pulmonary venous flow, which can also be measured with echocardiography. However, given the limitations of flow velocity, direct measurement of tissue velocity can significantly improve the characterization of diastolic dysfunction. The evolution of Doppler and speckle-based methods of assessing tissue motion have vastly improved our understanding of diastolic function. With the development of simpler algorithms for categorization, and their gradual adoption by perioperative echocardiographers, LVDD should be better diagnosed and treated to improve postoperative outcomes.

NONINVASIVE ASSESSMENT OF LEFT VENTRICULAR DIASTOLIC FUNCTION BY COLOR M-MODE DOPPLER ECHOCARDIOGRAPHY

Transmitral flow velocity pattern obtained by pulsed Doppler technique reflects left ventricular (LV)diastolic function, but an increase in left atrial pressure pseudo-normalizes the flow pattern and masks diastolic dysfunction. Flow propagation velocity (FPV) measured, using color M-mode Doppler and baseline-shift technique, represents an average velocity of early diastolic LV filling flow from mitral orifice to mid-ventricle. In patients with ischemic heart disease and dilated cardiomyopathy, including those with pseudonormalized transmitral flow pattern, FPV had good correlation with the time constant of early diastolic LV pressure decay (Tau), indicating that FPV is a useful noninvasive diastolic-function parameter which does not pseudo-normalize. Unlike the conventional Doppler parameters, FPV was well correlated with Tau in patients with hypertrophic cardiomyopathy, and was distinctly decreased even in hypertensive patents without LV hypertrophy. Thus, FPV is a unique noninvasive diastolic parameter, which can sensitively and accurately detect LV diastolic impairment.

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.

Is the E/V p index useful for evaluating prognosis in chronic heart failure with atrial fibrillation? A pilot study

BACKGROUND

The ratio of transmitral peak E wave velocity to color flow propagation velocity (E/V p index) has proved to be a significant predictor of prognosis in cardiac diseases with sinus rhythm. However, its usefulness in patients with atrial fibrillation (AF) and heart failure has not yet been established. The aim of this study was to determine the feasibility of using the E/V p index for the prediction of mortality and heart failure hospitalization in this group.

METHODS

We studied 66 ambulatory patients with stable congestive heart failure (CHF) functional class I-III and AF. Patients were divided into group A and B according to an E/V p index <1.5 and ≥1.5, respectively.

RESULTS

During follow-up (average 430 days) events were more common in group B (75 vs. 17%, log rank test; hazard ratio (HR)  = 6.8). By means of multivariate logistic regression analysis, E/V p proved to be an independent predictor of events (p = 0.0012).

CONCLUSIONS

In our patients with stable CHF and AF the E/V p index is a significant predictor of clinical outcome.

Independent association of coronary flow reserve with left ventricular relaxation and filling pressure in arterial hypertension

BACKGROUND

It has been recognized that "cross-talk" occurs between coronary flow and left ventricular (LV) function. This study tested the hypothesis that impairment of coronary flow reserve (CFR) in arterial hypertension is associated with LV systolic and diastolic dysfunction, independent of abnormalities in LV geometry.

METHODS

We studied 59 newly diagnosed, never-treated hypertensive patients, using transthoracic Doppler echocardiography including pulsed Tissue Doppler of mitral annulus and CFR on left anterior descending artery (low-dose dipyridamole). The study population was divided into two groups on the basis of age-normalized relative wall thickness (RWTn): 36 patients with normal LV geometry (RWTn < or = 0.41) and 23 patients with LV concentric geometry (RWTn > 0.41).

RESULTS

Patients with LV concentric geometry (RWTn > 0.41) had significantly lower values of midwall shortening (but not of endocardial shortening), longer isovolumic relaxation time (IVRT), lower Tissue Doppler-derived early diastolic velocity (Em), higher ratio of transmitral E velocity to Em, and lower CFR as compared to patients with normal LV geometry (RWTn < or = 0.41). In the whole population, a lower CFR was significantly associated with lower values of midwall shortening and Em, longer IVRT, and higher E/Em ratio. After controlling for heart rate, mean blood pressure, and RWTn, only the relation of CFR with IVRT, Em, and E/Em ratio remained significant.

CONCLUSIONS

Reduced midwall mechanics is associated with lower CFR, a relationship that depends on LV concentric geometry. A reduced CFR is associated with both impaired relaxation and increased filling pressure, a relation that is independent of LV geometry and pressure load.

Validation of isovolumic relaxation flow propagation velocity as an index of ventricular relaxation

To test the applicability of isovolumic relaxation flow propagation velocity (IRFPV) as an indicator of relaxation, 38 patients undergoing cardiac catheterization for chest pain were included. The time constant of isovolumic left ventricular (LV) pressure decline (tau) had a significant correlation with the LV end-diastolic pressure, the peak negative dp/dt, the LV end-diastolic dimension, the fractional shortening, the late diastolic transmitral flow velocity, the early and late diastolic mitral annular velocities, the rapid filling flow propagation velocity, and the natural logarithms of heart rate, ejection fraction, LV end-systolic dimension and IRFPV (r = -0.773, p < 0.001). IRFPV was selected as the major independent determinant of tau, explaining 46% of its variance. In prediction of tau > or =42 ms, the sensitivity and specificity were 100% and 83% for IRFPV < or =104 cm/s, 77% and 67% for the rapid filling flow propagation velocity < or =50 cm/s, and 58% and 67% for the early diastolic mitral annular velocity < or =8 cm/s, respectively. In conclusion, our data suggest that IRFPV could be a better marker of LV relaxation than other parameters, as the rapid filling flow propagation velocity or the early diastolic mitral annular velocity.

New echocardiographic applications for assessing global left ventricular diastolic function

A number of promising and highly technological echocardiographic imaging tools have recently been introduced to assess left ventricular diastolic function (i.e., the capacity of the ventricle to relax and fill). They permit quantification of distinct features of intraventricular blood flow velocity and pressure fields and myocardial tissue velocities. However, accurate interpretation of the new images and clinical indices is still cumbersome, as basic knowledge about intraventricular hemodynamics and ventricular wall mechanics is often insufficient. This review article provides a comprehensive and original overview of the hemodynamical and mechanical events that occur during diastole and discusses how this new information can be used in the clinical and research setting to evaluate diastolic function in the healthy and the diseased heart. It furthermore aims to explain the underpinnings of the techniques in such a way that the underlying biomechanical concepts (fluid dynamics and wall mechanics) become less obscure to cardiologists and echocardiographers and such that the biomedical engineers are given some insights into the avalanche of diastolic performance indices that currently exist.

Effects of sevoflurane and propofol on left ventricular diastolic function in patients with pre-existing diastolic dysfunction

BACKGROUND

The effects of anaesthetics on left ventricular (LV) diastolic function in patients with pre-existing diastolic dysfunction are not well known. We hypothesized that propofol but not sevoflurane will worsen the pre-existing LV diastolic dysfunction.

METHODS

Of 24 randomized patients, 23 fulfilled the predefined echocardiographic criterion for diastolic dysfunction. They received general anaesthesia with sevoflurane 1 MAC (n=12) or propofol 4 mug ml(-1) (n=11). Echocardiographic examinations were performed at baseline and in anaesthetized patients under spontaneous breathing and under positive pressure ventilation. Analysis focused on peak early diastolic velocity of the mitral annulus (E(a)).

RESULTS

During spontaneous breathing, E(a) was higher in the sevoflurane than in the propofol group [mean (95% CI) 7.0 (5.9-8.1) vs 5.5 (4.7-6.3) cm s(-1); P<0.05], reflecting an increase of E(a) from baseline only in the sevoflurane group (P<0.01). Haemodynamic findings were similar in both groups, but the end-tidal carbon dioxide content was more elevated in the propofol group (P<0.01). During positive pressure ventilation, E(a) was similarly low in the sevoflurane and propofol groups [5.3 (4.2-6.3) and 4.4 (3.6-5.2) cm s(-1), respectively].

CONCLUSIONS

During spontaneous breathing, early diastolic function improved in the sevoflurane but not in the propofol group. However, during positive pressure ventilation and balanced anaesthesia, there was no evidence of different effects caused by the two anaesthetics.

Intraventricular Pressure Gradients in Left Ventricular Aneurysms Determined by Color M-Mode Doppler Method: An Animal Study

BACKGROUND

Left ventricular aneurysm (LVA) may affect diastolic intraventricular blood flow. Color M-mode (CMM) Doppler flow propagation patterns are abnormal in the presence of apical aneurysms. The aim of this study was to validate the accuracy of CMM echocardiography for assessing the existence and size of LVA and to determine the intraventricular pressure gradient in LVA.

METHODS

CMM of the transmitral inflow in early diastole was obtained from the apical 4-chamber view in 19 sheep. The presence of the break point where the velocity decreased abruptly in the mitral inflow (point D) was determined and the distance between the apex and point D was measured. The intraventricular pressure difference between the base and the apex was measured by a catheter while it was calculated using CMM with the Euler equation.

RESULTS

The presence of the break point D showed 84% sensitivity and 100% specificity for determining the existence of an LVA. Distance between the apex and point D correlated well with scar size. Catheter- and CMM-derived intraventricular pressure difference correlated and agreed well (y = 1.0 x -0.2, r = 0.94).

CONCLUSIONS

The point of abrupt decrease in propagation velocity of the CMM recording indicated the presence and size of LVA. Intraventricular pressure gradients were determined noninvasively by CMM echocardiography with reasonable accuracy.

Traditional and Color M-Mode Parameters of Left Ventricular Diastolic Function During Low-dose Dobutamine Stress Echocardiography: Relations to Contractility Reserve

BACKGROUND

Cross-sectional studies reported that left ventricular (LV) systolic and diastolic functions are correlated. However, whether changes in wall-motion score index (WMSI) or 2-dimensional ejection fraction (EF) predict changes of Doppler parameters of LV diastolic function is unclear.

METHODS

Patients with known or suspected history of coronary artery disease underwent assessment of LV systolic function (WMSI, EF) and diastolic function at baseline and during stress echocardiography by low-dose dobutamine (LDD) (peak infusion 10 microg/kg/min). Peak velocities of early (E) and late (A) LV filling waves and E wave deceleration time were measured according to standard protocol. E wave propagation rate (EVp) was assessed by color Doppler M-mode across the mitral valve. Tei index was calculated as: (A wave to E wave time - ejection time)/ejection time. Changes at LDD were calculated as: 100 x (value at LDD - value at baseline)/baseline.

RESULTS

The study group comprised 66 patients, mean age 61 +/- 10 years, 80% men. Worse LV systolic function was associated with more severely impaired LV diastolic function both at baseline and at LDD. However, percent change of WMSI and change in EF did not correlate with percent change of EVp and E/E wave propagation rate, but with percent change of Tei index. At LDD, patients with myocardial viability did not show greater percent change of LV diastolic function parameters but significantly lower Tei index.

CONCLUSIONS

In patients with suspected or known coronary artery disease, assessment of diastolic function reserve by LDD stress echocardiography using traditional and color M-mode Doppler may add quantitative information on myocardial function beyond traditional assessment of contractility reserve by WMSI or EF.

Color M-mode flow propagation velocity: is it really preload independent?

OBJECTIVE

This study investigates the change in flow propagation velocity (FPV) in uremic patients who undergo regular hemodialysis (H/D).

MATERIALS AND METHODS

We studied 93 uremic patients (44 men and 49 women; 59 +/- 14-years-old) receiving regular hemodialysis. Patients were separated by baseline left ventricular ejection fraction (LVEF): 71 patients with LVEF > 50% (group 1), 13 patients with LVEF 35-50% (group 2), 7 patients with LVEF < 35% (group 3). All patients were in sinus rhythm before H/D. They received complete transthoracic echocardiographic examinations. Flow propagation velocity was measured by color M-mode echocardiography in apical four chambers view. All these parameters were obtained before and after H/D. Paired data were compared. According to different H/D amounts, we viewed the FPV response after H/D in variant baseline LVEF groups.

RESULT

The baseline FPV became lower in patients with low LVEF. After H/D, obvious decrement of FPV occurred in group 1, but there were no obvious changes in groups 2 and 3. In fact, a slight increment of FPV was found in group 3. In patients with baseline LVEF > 50%, FPV after H/D was almost always lower, regardless of H/D amount. But there was different response in patients with baseline LVEF < 50%.

CONCLUSION

Flow propagation velocity is preload independent in patients with LVEF < 50%, but it is preload-dependent in patients with LVEF > 50%.

Left ventricular inflow propagation velocity at pulsed wave Doppler analysis: An index of relaxation

To test whether left ventricular inflow propagation velocity at the pulsed wave Doppler analysis (IPVpw) is a useful noninvasive index of relaxation, 21 patients under coronary angiography for chest pain were included for simultaneous catheter-based and Doppler studies. IPVpw was derived through the application of range ambiguity, and the time constant of isovolumic left ventricular pressure decline (tau) was acquired by a previously described method. At baseline status, IPVpw correlated significantly with the peak negative dP/dt and tau ( r = -0.609, P = .003), but not with the peak velocity of transmitral early flow (E) wave. Sublingual application of nitroglycerin increased heart rate, decreased the transmitral E velocity and transmitral E-to-A velocity ratio, and prolonged the deceleration time of the transmitral E wave. However, there was no significant impact on IPVpw, peak negative dP/dt, or tau. IPVpw correlated with tau ( r = -0.533, P < .001) at the combined analysis of the data before and after nitroglycerin application. In conclusion, IPVpw is a preload-independent, noninvasive index of left ventricular relaxation.

Assessment of propagation velocity by contrast echocardiography for standardization of color Doppler propagation velocity measurements

BACKGROUND

Color Doppler propagation velocity (Vp) (color-Vp) has not yet been standardized, although it should be able to specifically reflect the intraventricular movements of left ventricular (LV) inflow. Because contrast echocardiography can depict a specified flow, we used this modality to standardize measurements of color-Vp of LV inflow.

METHODS

We performed contrast echocardiographic examinations in 100 patients (70 men, 30 women; age 53 +/- 12 years). Four types of color-Vp were measured: by the flow wave front method and by aliasing method using 3 aliasing velocity levels based on the peak velocity of early diastolic flow of transmitral flow. We also determined contrast echocardiographic Vp by M-mode imaging of LV inflow (contrast-Vp).

RESULTS

Contrast-Vp and all 4 types of color-Vp could be compared in 86 patients. Contrast-Vp was significantly lower than color-Vp ( P < .01), except for color-Vp measured at the aliasing level 50% > peak velocity of early diastolic flow >/= 40% (color-Vp 40). A close relationship was observed between contrast-Vp and color-Vp 40 ( r = 0.801, P < .0001). Contrast-Vp and color-Vp 40 showed high ability to detect abnormal transmitral flow patterns according to receiver operating characteristics curves (area under curve for contrast-Vp, 0.94; for color-Vp 40, 0.90).

CONCLUSIONS

Our results should be useful in standardization of color-Vp measurement to specifically reflect propagation of the fluid elements derived from LV inflow, with ability to distinguish LV filling abnormalities.

Preload-dependent variation of the propagation velocity in patients with congestive heart failure

BACKGROUND

Although color Doppler M-mode propagation velocity (Vp) is preload-independent, the variation in Vp with the temporal variation of preload in the clinical setting has not been evaluated. Because left ventricular filling pressure changes dramatically with treatment of congestive heart failure (CHF), we hypothesized that preload-dependent variations in Vp occur with treatment of CHF.

METHODS

We performed Doppler echocardiographic and hemodynamic evaluation in 24 patients with CHF (15 men, 62 +/- 10 years) at initial presentation (baseline study) and after CHF had improved with therapy (second study).

RESULTS

The interval between the baseline and the second study was 48.6 +/- 21.5 hours. Vp decreased between the baseline study (41 +/- 5 cm/s) and the second study (28 +/- 5 cm/s, P <.0001). Only the change in pulmonary capillary wedge pressure (-8.3 +/- 3.3 mm Hg) between the baseline and second study was an independent predictor of the change in Vp (-12.5 +/- 5.9 cm/s) by stepwise linear regression (r = 0.68, P =.0002).

CONCLUSIONS

Vp decreases significantly with decreases in pulmonary capillary wedge pressure with the treatment of CHF. The preload-dependent variation should be taken into account in the assessment of Vp in patients with CHF.

Color M-mode and Doppler tissue evaluation of diastolic function in children: simultaneous correlation with invasive indices

OBJECTIVE

The purpose of this study was to explore the validity of diastolic indices derived from color M-mode Doppler and Doppler tissue imaging in a heterogeneous group of pediatric patients by comparing them with simultaneously obtained invasive indices of diastolic function.

METHODS

A total of 20 children undergoing left heart catheterization had echocardiographic images recorded simultaneously with high-fidelity left ventricular (LV) pressure tracings. Transmitral Doppler, pulmonary vein Doppler, Doppler tissue imaging, and color M-mode Doppler flow propagation velocity were recorded. LV peak negative dP/dt, the time constant of isovolumic relaxation, and LV end-diastolic pressure were compared with the echocardiographic indices.

RESULTS

The ratio of peak E-wave mitral velocity/propagation velocity correlated significantly with LV end-diastolic pressure (r = 0.71; P <.001). Propagation velocity correlated with the time constant of isovolumic relaxation (r = -0.56; P =.01) and peak negative dP/dt (r = 0.50; P <.03). Septal mitral annular myocardial velocity correlated significantly with the time constant of isovolumic relaxation (r = -0.58, P =.01).

CONCLUSION

The newer diastolic indices derived from color M-mode Doppler and Doppler tissue imaging appear to be a helpful adjunct in the noninvasive assessment of diastolic function in children.

Nonelectrocardiographic evidence that both ischemic preconditioning and adenosine preconditioning exist in humans

OBJECTIVES

The objective of this study was to use electrocardiogram (ECG)-independent parameters to determine whether preconditioning (PC) exists in humans during percutaneous transluminal coronary angioplasty (PTCA).

BACKGROUND

Several studies suggest that both ischemia and adenosine induce PC in the human heart during PTCA. However, because almost all of these studies relied on ST-segment shifts as indicators of the severity of ischemia, their conclusions continue to be questioned, and the very existence of ischemic or adenosine PC in humans remains controversial.

METHODS

Eighteen patients received either intracoronary adenosine (n = 9) or normal saline (n = 9); 10 min later, they underwent PTCA (three 2-min balloon inflations 5 min apart).

RESULTS

Compared with the first inflation, in untreated patients the second and third inflations were associated with less systolic dysfunction (two-dimensional echocardiography), less diastolic dysfunction (color M-mode echocardiography), less lactate production, and less H(+) release into the great cardiac venous blood. In adenosine-treated patients, the extent of all of these abnormalities during the first inflation was less than in untreated patients and did not change with subsequent inflations.

CONCLUSIONS

Previous exposure to a brief episode of ischemia (first balloon inflation) or to adenosine produces concordant decreases in ECG, subjective, mechanical, and metabolic manifestations of ischemia during PTCA. These data support the concept that both ischemic PC and pharmacologic PC exist in humans and that PTCA is a useful clinical setting in which to discern their mechanism.

Left ventricular inflow propagation velocity: comparisons between pulsed wave and color M-mode Doppler echocardiography

Sixty-six participants (age 58 +/- 16 years) were included for evaluation of the relationship between color M-mode and pulsed wave Doppler left ventricular inflow propagation velocity (LVIPVcmm and LVIPVpw, respectively). LVIPVpw was measured through the application of the range ambiguity phenomenon, and LVIPVcmm was obtained by manually tracing the first aliasing velocity during the early filling. The variability for LVIPVpw measurements was significantly less than that for LVIPVcmm measurements. There was a significant correlation (r = 0.678, P <.001) between LVIPVcmm and LVIPVpw for all study participants. However, LVIPVpw was greater than LVIPVcmm, especially when the inflow propagation time was relatively short. Age was the only determinant of both LVIPVcmm and LVIPVpw in the control group. As for the patients with diseases retarding inflow propagation, age remained its determinant. However, its impact decreased and the end-systolic dimension and fractional shortening of the left ventricle, instead, turned out to be its major determinant. In conclusion, LVIPVpw measurements are more reproducible than LVIPVcmm measurements. LVIPVpw correlates with LVIPVcmm and their difference significantly correlates with left ventricular inflow propagation time.

A new echocardiographic method for the assessment of the severity of aortic regurgitation: color M-mode flow propagation velocity

PURPOSE

Echocardiographic Doppler methods widely used in assessment of the severity of aortic regurgitation (AR) are considered sensitive and reliable. However, they all have limitations for quantitation of AR. The color M-mode Doppler flow propagation velocity (FPV) method has been shown to provide useful insights in the evaluation of left ventricular diastolic function and appears to be minimally affected with preload changes. Clinical data regarding the value of FPV in the determination of the significance of valvular insuffiencies are lacking. The purpose of this study was to evaluate the use of FPV in measurement of the severity of AR and to compare its reliability with angiography and other echocardiographic methods.

METHODS

Twenty-nine patients (13 male, 16 female) who had cardiac catheterization for various reasons before echocardiographic evaluation were included. The mean age was 53.6 +/- 13.4 years. At the time of cardiac catheterization, the degree of AR was assessed as mild in 10 patients, as moderate in 12, and as severe in 7. In all patients, FPV measurements of AR were obtained with color M-mode Doppler in the apical 5-chamber view. Regurgitation jet height and its ratio to left ventricular outflow obtained in the parasternal long axis with color flow Doppler, pressure half-time, and slope of AR obtained with continuous wave Doppler in apical 5-chamber view were other echocardiographic methods chosen for comparison.

RESULTS

The mean values of FPV were 93.1 +/- 18.4 cm/s, 49.8 +/- 8.0 cm/s, and 31.7 +/- 4.9 cm/s in severe, moderate, and mild AR groups, respectively (P <.001). Significant correlation was observed between angiographic grades, FPV, pressure half-time, slope, and jet height and ratio to left ventricular outflow (P <.0001, r = 0.93; P <.0001, r = -0.81; P <.0001, r = 0.76; P <.0001, r = 0.92, respectively).

CONCLUSION

FPV is a simple, practical, and reliable method for the quantification of AR.

Comparison of Doppler echocardiography, color M-mode Doppler, and Doppler tissue imaging for the estimation of pulmonary capillary wedge pressure

To overcome the limitations of mitral inflow parameters for predicting pulmonary capillary wedge pressure (PCWP), combined indices (with Doppler tissue imaging or color M-mode Doppler) have been developed. This study was aimed to compare the accuracy of these indices to predict PCWP. Sixty-one patients were studied. The best correlations with PCWP were found for indices that combined isovolumic relaxation time with flow propagation velocity (color M-mode) or early diastolic velocity of the lateral mitral annulus (Doppler tissue). Both closely tracked changes in PCWP. The color M-mode-derived index was the most accurate in patients with normal systolic function.

Echocardiographic determinants of mitral early flow propagation velocity

Transmitral color Doppler early diastolic flow propagation velocity (Vp) has been correlated with the left ventricular (LV) relaxation time constant tau in dilated cardiomyopathy and ischemic heart disease. The aim of this study was to investigate the independent influence of LV systolic function and geometry, and of LV relaxation, on Vp in an unselected outpatient population. We studied 30 normal subjects and 130 patients (hypertensive LV hypertrophy, aortic valve stenosis or prosthesis, hypertrophic cardiomyopathy, coronary artery disease, dilated cardiomyopathy, aortic or mitral valve regurgitation). In all, we noninvasively measured LV geometry, mass, systolic function, wall motion dyssynergy, and diastolic function (abnormal relaxation or restrictive LV Doppler filling patterns). The Vp was similar in normal subjects and in patients (51 +/- 14 vs 53 +/- 25 cm/s). In normal subjects, the determinants of Vp at multiple regression analysis were isovolumic relaxation time, 2-dimensional cardiac index, and mitral E-wave velocity-time integral. In all, the main determinants were LV ejection fraction, percent of segmental wall dyssynergy, and isovolumic relaxation time and age. The Vp was highest in hypertrophic (75 +/- 25 cm/s, p <0.05 vs normal subjects) and lowest in dilated (35 +/- 13 cm/s, p = NS) cardiomyopathy. During multivariate analysis of variance, percent of wall dyssynergy (but not diffuse LV hypokinesia) independently reduced Vp (p = 0.02). The latter was not influenced by the LV filling pattern. Thus, in an unselected clinical population, prolonged relaxation per se does not influence Vp if LV systolic dysfunction and/or wall dyssynergy is absent-the latter factors are important independent determinants of Vp, which is determined by multiple factors.

Color M-mode and pulsed wave tissue Doppler echocardiography: powerful predictors of cardiac events after first myocardial infarction

To assess the association between color M-mode flow propagation velocity and the early diastolic mitral annular velocity (E(m)) obtained with tissue Doppler echocardiography and to assess the prognostic implications of the indexes, echocardiography was performed on days 1 and 5, and 1 and 3 months after a first myocardial infarction in 67 consecutive patients. Flow propagation velocity correlated well with E(m) (r = 0.72, P <.0001). The ratio of peak E-wave velocity (E) to flow propagation velocity also correlated well with E/E(m) (r = 0.87, P <.0001). The positive predictive value of E/FPV > or =1.5 to identify patients with Killip class > or =II was 90%, and the negative predictive value 92%. The corresponding values for E/E(m) > or =10 were 70% and 90%. Cox proportional hazards analysis identified E/flow propagation velocity > or =1.5 (relative risk, 12.4 [95% confidence interval, 4.1-37.3]), E/E(m) > or =10 (relative risk, 11.5 [95% confidence interval, 3.8-34.7]), and Killip class > or =II (relative risk, 7.8 [95% confidence interval, 1.6-40.4]) to be predictors of the composite end point of cardiac death and readmission because of heart failure. Thus flow propagation velocity and E(m) are closely related after myocardial infarction and appear to have similar prognostic information.

Estimation of diastolic intraventricular pressure gradients by Doppler M-mode echocardiography

Previous studies have shown that small intraventricular pressure gradients (IVPG) are important for efficient filling of the left ventricle (LV) and as a sensitive marker for ischemia. Unfortunately, there has previously been no way of measuring these noninvasively, severely limiting their research and clinical utility. Color Doppler M-mode (CMM) echocardiography provides a spatiotemporal velocity distribution along the inflow tract throughout diastole, which we hypothesized would allow direct estimation of IVPG by using the Euler equation. Digital CMM images, obtained simultaneously with intracardiac pressure waveforms in six dogs, were processed by numerical differentiation for the Euler equation, then integrated to estimate IVPG and the total (left atrial to left ventricular apex) pressure drop. CMM-derived estimates agreed well with invasive measurements (IVPG: y = 0.87 x + 0.22, r = 0.96, P < 0.001, standard error of the estimate = 0.35 mmHg). Quantitative processing of CMM data allows accurate estimation of IVPG and tracking of changes induced by β-adrenergic stimulation. This novel approach provides unique information on LV filling dynamics in an entirely noninvasive way that has previously not been available for assessment of diastolic filling and function.

Pseudonormal and restrictive filling patterns predict left ventricular dilation and cardiac death after a first myocardial infarction: a serial color M-mode Doppler echocardiographic study

OBJECTIVES

We sought to assess the prognostic value of left ventricular (LV) filling patterns, as determined by mitral E-wave deceleration time (DT) and color M-mode flow propagation velocity (Vp), on cardiac death and serial changes in LV volumes after a first myocardial infarction (MI).

BACKGROUND

Combined assessment of DT and Vp allows separation of the effects of compliance and relaxation on LV filling, thereby allowing identification of pseudonormal filling. This may be valuable after MI, where abnormal LV filling is frequently present.

METHODS

Echocardiography was performed within 24 h, five days and one and three months after MI in 125 unselected consecutive patients. Normal filling was defined as DT 140 to 240 ms and Vp > or =45 cm/s; impaired relaxation as DT > or =240 ms; pseudonormal filling as DT 140 to 240 ms and Vp <45 cm/s; and restrictive filling as DT <140 ms.

RESULTS

Left ventricular filling was normal in 38 patients; impaired relaxation in 38; pseudonormal in 23; and restrictive in 26. End-systolic and end-diastolic volume indexes were significantly increased during the first three months after MI in patients with pseudonormal or restrictive filling (37+/-15 vs. 47+/-19 ml/m2, p<0.0005 and 71+/-20 vs. 88+/-24 ml/m2, p<0.0005, respectively). During a follow-up period of 12+/-7 months, 33 patients died. Mortality was significantly higher in patients with impaired relaxation (p = 0.02), pseudonormal filling (p<0.00005) and restrictive filling (p<0.00005), compared with patients with normal filling. On Cox analysis, restrictive filling (p = 0.003), pseudonormal filling (p = 0.006) and Killip class > or =II (p = 0.008) independently predicted cardiac death, compared with clinical and echocardiographic variables.

CONCLUSIONS

Pseudonormal or restrictive filling patterns are related to progressive LV dilation and predict cardiac death after a first MI.

Preload dependence of color M-mode Doppler flow propagation velocity in controls and in patients with left ventricular dysfunction

The purpose of this study was to assess the effects of preload alterations on color M-mode flow propagation velocity (Vp) in volunteers with normal left ventricular (LV) function and in patients with depressed LV function. Color M-mode Doppler echocardiography was performed during Valsalva maneuver, passive leg lifting, and after administration of nitroglycerin in 30 healthy volunteers and in 30 age- and sex-matched patients with previous myocardial infarction (MI). Mean Vp in controls was 74 +/- 15 cm/s at baseline and 46 +/- 15 cm/s in MI patients (P <.0005). In both groups, minor changes in Vp were seen during preload alterations; however, these were not significant (control P =.72, MI P =.31). In both groups, peak E-wave velocity (P <.0005), ratio of early-to-late peak velocities (P <.0005), and E-wave deceleration time (P <.0005) were found to change during preload alterations. In conclusion, we found that in controls and patients with previous MI, the color M-mode flow propagation velocity is not affected significantly by preload.

Usefulness of early diastolic flow propagation velocity measured by color M-mode Doppler technique for the assessment of left ventricular diastolic function in patients with hypertrophic cardiomyopathy

Flow propagation velocity (FPV) of left ventricular (LV) filling flow has been shown to be a useful index for the evaluation of LV diastolic function, which is relatively independent of preload in myocardial infarction and dilated cardiomyopathy, but the usefulness of FPV for hypertrophic cardiomyopathy (HCM) has not yet been determined. In 23 HCM patients and 26 control subjects, peak transmitral flow velocities in early diastole (E) and during atrial contraction (A), E/A ratio, deceleration time of E velocity, and isovolumic relaxation time were measured with the conventional Doppler technique, and FPV was measured from color M-mode Doppler images of LV filling flow. The time constant of LV isovolumic pressure decay (tau) was measured by a micro-manometer-tipped catheter in all HCM patients and 13 control subjects. Flow propagation velocity was significantly lower and deceleration time was significantly greater in HCM patients than in the control subjects, though no significant differences were observed in the other noninvasive indexes. Tau was significantly prolonged in HCM patients compared with that of control subjects (54+/-12 cm/s and 32 +/-7 cm/s, respectively; P<.0001). While the conventional indexes did not correlate with tau among the 36 patients in whom invasive studies were performed, FPV correlated well with tau (r = -0.76, P<.0001). Flow propagation velocity is a useful noninvasive index for the assessment of LV diastolic function in patients with HCM.

From digital image processing of colour Doppler M-mode maps to noninvasive evaluation of the left ventricular diastolic function: a dedicated software package

Noninvasive estimation of diastolic pressure gradients has recently been validated using the space-temporal velocity distribution available from colour Doppler M-mode (CDM). However, the methods currently applied for analysing CDM patterns of left ventricular (LV) filling have limitations, such as lack of automation, subjective variability and limited use of digital velocity map. For this reason, we have developed software able to acquire and process the CDM maps; thus, providing an easily interpretable graphical and numerical display. The pressure field is obtained by approximating the derivatives with centred finite differences via the incompressible Navier-Stokes equations. After digital filtering of the noise and the removal of the colour black spots, the velocity field is utilised to compute the pressure gradient field and the pressure values by spatial integration. It is concluded that automatic quantification of colour CDM patterns is feasible and will be a strategic tool in the investigation of one of the most intriguing topics in cardiology.

Ratio of left ventricular peak E-wave velocity to flow propagation velocity assessed by color M-mode Doppler echocardiography in first myocardial infarction: prognostic and clinical implications

OBJECTIVES

To determine the ability of the ratio of peak E-wave velocity to flow propagation velocity (E/Vp) measured with color M-mode Doppler echocardiography to predict in-hospital heart failure and cardiac mortality in an unselected consecutive population with first myocardial infarction (MI).

BACKGROUND

Several experimental studies indicate color M-mode echocardiography to be a valuable tool in the evaluation of diastolic function, but data regarding the clinical value are lacking.

METHODS

Echocardiography was performed within 24 h of arrival at the coronary care unit in 110 consecutive patients with first MI. Highest Killip class was determined during hospitalization. Patients were divided into groups according to E/Vp <1.5 and > or =1.5.

RESULTS

During hospitalization 53 patients were in Killip class > or =II. In patients with E/Vp > or =1.5, Killip class was significantly higher compared with patients with E/Vp <1.5 (p < 0.0001). Multivariate logistic regression analysis identified E/Vp > or =1.5 to be the single best predictor of in-hospital clinical heart failure when compared with age, heart rate, E-wave deceleration time (Dt), left ventricular (LV) ejection fraction, wall motion index, enzymatic infarct size and Q-wave MI. At day 35 survival in patients with E/Vp <1.5 was 98%, while for patients with E/Vp > or =1.5, it was 58% (p < 0.0001). Cox proportional hazards model identified Dt <140 ms, E/Vp > or =1.5 and age to be independent predictors of cardiac death, with Dt < 140 ms being superior to age and E/Vp.

CONCLUSIONS

In the acute phase of MI, E/Vp > or =1.5 measured with color M-mode echocardiography is a strong predictor of in-hospital heart failure. Furthermore, E/Vp is superior to systolic measurements in predicting 35 day survival although Dt <140 ms is the most powerful predictor of cardiac death.

Combined use of pulsed and color M-mode Doppler echocardiography for the estimation of pulmonary capillary wedge pressure: an empirical approach based on an analytical relation

OBJECTIVES

We sought a noninvasive estimation of pulmonary capillary wedge pressure (Pw) by means of the information obtained from transmitral pulsed Doppler and color M-mode Doppler flow propagation velocity (FPV).

BACKGROUND

Pulsed Doppler parameters have limited accuracy for the estimation of Pw because they are determined by left atrial pressure and other parameters such as ventricular relaxation. Recently, a good correlation has been found between the rate of ventricular relaxation (tau, tau) and FPV measured by color M-mode Doppler echocardiography.

METHODS

We studied 20 patients who underwent invasive hemodynamic monitoring. By multilinear regression analysis, the relationships between Pw and Doppler parameters, FPV, and a noninvasive estimate (P(est)) based on the Weiss' equation (substituting tau for 1/FPV) were determined. A simplified index based on the results obtained was then tested in an additional group of 34 patients.

RESULTS

By multiple regression analysis only isovolumic relaxation time (IVRT) (p = 0.0096) and P(est) (p = 0.0043) were related to Pw. A derived empirical index, 10(3)/([2 x IVRT] + FPV), was strongly correlated with Pw in the entire group according to the regression equation Pw = 4.5 x (10(3)/[[2 x IVRT] + FPV]) - 9 (r = 0.89, p < 0.0001, [standard error of the estimate] SEE = 3.3 mm Hg). The sensitivity and specificity for the prediction of Pw > 15 mm Hg were 90% and 100%, respectively.

CONCLUSIONS

The combined use of FPV as a surrogate for tau and IVRT permits a close prediction of Pw.