Noninvasive estimation of the instantaneous first derivative of left ventricular pressure using continuous-wave Doppler echocardiography

Performance of the Hypotension Prediction Index with non-invasive arterial pressure waveforms in non-cardiac surgical patients

An algorithm derived from machine learning uses the arterial waveform to predict intraoperative hypotension some minutes before episodes, possibly giving clinician’s time to intervene and prevent hypotension. Whether the Hypotension Prediction Index works well with noninvasive arterial pressure waveforms remains unknown. We therefore evaluated sensitivity, specificity, and positive predictive value of the Index based on non-invasive arterial waveform estimates. We used continuous hemodynamic data measured from ClearSight (formerly Nexfin) noninvasive finger blood pressure monitors in surgical patients. We re-evaluated data from a trial that included 320 adults ≥ 45 years old designated ASA physical status 3 or 4 who had moderate-to-high-risk non-cardiac surgery with general anesthesia. We calculated sensitivity and specificity for predicting hypotension, defined as mean arterial pressure ≤ 65 mmHg for at least 1 min, and characterized the relationship with receiver operating characteristics curves. We also evaluated the number of hypotensive events at various ranges of the Hypotension Prediction Index. And finally, we calculated the positive predictive value for hypotension episodes when the Prediction Index threshold was 85. The algorithm predicted hypotension 5 min in advance, with a sensitivity of 0.86 [95% confidence interval 0.82, 0.89] and specificity 0.86 [0.82, 0.89]. At 10 min, the sensitivity was 0.83 [0.79, 0.86] and the specificity was 0.83 [0.79, 0.86]. And at 15 min, the sensitivity was 0.75 [0.71, 0.80] and the specificity was 0.75 [0.71, 0.80]. The positive predictive value of the algorithm prediction at an Index threshold of 85 was 0.83 [0.79, 0.87]. A Hypotension Prediction Index of 80–89 provided a median of 6.0 [95% confidence interval 5.3, 6.7] minutes warning before mean arterial pressure decreased to < 65 mmHg. The Hypotension Prediction Index, which was developed and validated with invasive arterial waveforms, predicts intraoperative hypotension reasonably well from non-invasive estimates of the arterial waveform. Hypotension prediction, along with appropriate management, can potentially reduce intraoperative hypotension. Being able to use the non-invasive pressure waveform will widen the range of patients who might benefit.

Clinical Trial Number: ClinicalTrials.gov NCT02872896.

Influence of changes in ventricular systolic function and loading conditions on pulse contour analysis-derived femoral dP/dtmax

BACKGROUND

Femoral dP/dt_max (maximum rate of the arterial pressure increase during systole) measured by pulse contour analysis has been proposed as a surrogate of left ventricular (LV) dP/dt_max and as an estimator of LV systolic function. However, femoral dP/dt_max may be influenced by LV loading conditions. In this study, we evaluated the impact of variations of LV systolic function, preload and afterload on femoral dP/dt_max in critically ill patients with cardiovascular failure to ascertain its reliability as a marker of LV systolic function.

RESULTS

We performed a prospective observational study to evaluate changes in femoral dP/dt_max, thermodilution-derived variables (PiCCO2-Pulsion Medical Systems, Feldkirchen, Germany) and LV ejection fraction (LVEF) measured by transthoracic echocardiography during variations in dobutamine and norepinephrine doses and during volume expansion (VE) and passive leg raising (PLR). Correlations with arterial pulse and systolic pressure, effective arterial elastance, total arterial compliance and LVEF were also evaluated. In absolute values, femoral dP/dt_max deviated from baseline by 21% (201 ± 297 mmHg/s; p = 0.013) following variations in dobutamine dose (n = 17) and by 15% (177 ± 135 mmHg/s; p < 0.001) following norepinephrine dose changes (n = 29). Femoral dP/dt_max remained unchanged after VE and PLR (n = 24). Changes in femoral dP/dt_max were strongly correlated with changes in pulse pressure and systolic arterial pressure during dobutamine dose changes (R = 0.942 and 0.897, respectively), norepinephrine changes (R = 0.977 and 0.941, respectively) and VE or PLR (R = 0.924 and 0.897, respectively) (p < 0.05 in all cases). Changes in femoral dP/dt_max were correlated with changes in LVEF (R = 0.527) during dobutamine dose variations but also with effective arterial elastance and total arterial compliance in the norepinephrine group (R = 0.638 and R = - 0.689) (p < 0.05 in all cases).

CONCLUSIONS

Pulse contour analysis-derived femoral dP/dt_max was not only influenced by LV systolic function but also and prominently by LV afterload and arterial waveform characteristics in patients with acute cardiovascular failure. These results suggest that femoral dP/dt_max calculated by pulse contour analysis is an unreliable estimate of LV systolic function during changes in LV afterload and arterial load by norepinephrine and directly linked to arterial waveform determinants.

Outflow Cannula Systolic Slope in Patients With Left Ventricular Assist Devices: A Novel Marker of Myocardial Contractility

Left ventricular (LV) unloading with a LV assist device (LVAD) reverse remodels the heart and may lead to favorable changes in cellular architecture and LV geometry promoting myocardial recovery. Currently, there are no standardized methods for evaluating myocardial recovery. This study assesses the systolic slope of the LVAD outflow cannula as a marker for myocardial contractility. Doppler echocardiography (transthoracic echocardiogram [TTE]) of the LVAD outflow cannula and TTE of the LV cavity were prospectively collected in 57 patients with LVADs. Systolic acceleration of the LVAD outflow cannula was measured in each patient as the peak change of velocity over time (dv/dt) during systole from continuous-wave Doppler signal acquired from the LVAD outflow cannula. Ventricular volumes were concurrently measured by TTE. In a subset of 10 patients, the systolic slope was measured during each stage of a ramp study to study the properties of this parameter across a variety of loading conditions. The systolic slope of the LVAD outflow cannula was successfully measured in 53 of 57 patients (93%). Systolic slope strongly correlated with ejection fraction (EF) (R = 0.92). Analysis of systolic slope stratified by EF (EF >30%, EF 20-30%, EF 10-20%, and EF <10%) revealed systolic slopes that were significantly different between the groups (1,371 cm/s ± 324; 983 cm/s ± 122; 578 cm/s ± 139; and 495 cm/s ± 107, respectively; p < 0.001). Systolic slope did not change significantly across variable preload and afterload conditions during a ramp study. Systolic slope of the LVAD outflow cannula strongly correlates with EF and can be used to assess underlying myocardial contractility across a variety of LVAD loading conditions.

IN-SILICO MODELING OF LEFT VENTRICLE TO SIMULATE DILATED CARDIOMYOPATHY AND CF-LVAD SUPPORT

Numerical modeling of the left ventricle dynamics plays an important role in testing different physiological scenarios and treatment techniques before the in vitro and in vivo assessments. However, utilized left ventricle model becomes vital in the simulations because validity of the results depends on the response of the numerical model to the parameter changes and additional sub-models for the applied treatment techniques. In this study, it is aimed to evaluate different numerical left ventricle models describing healthy and failing ventricle dynamics as well as the response of these models under continuous flow left ventricular assist device support. Six different numerical left ventricle models which include time varying elastance and single fiber contraction approaches are selected and applied in combination with a closed loop electric analogue of the circulation to achieve this purpose. The time varying elastace models relate ventricular pressure and volume changes in a simplistic way while the single fiber contraction models combine different scales ranging from protein to organ level. Change of the hemodynamic signals at the organ level for healthy, failing and CF-LVAD supported left ventricle models shows functionality of these models and helps to understand usability of them for different purposes.

Usefulness of the maximum rate of pressure rise in the central and peripheral arteries after weaning from cardiopulmonary bypass in pediatric congenital heart surgery: A retrospective analysis

The maximum rate of pressure rise (dP/dtmax) in radial artery has been proposed as a noninvasive surrogate of aortic dp/dtmax, reflecting left ventricular (LV) contractility in children. The aim of this study was to investigate relationship between aortic and radial dp/dtmax at weaning from cardiopulmonary bypass (CPB) and usefulness of these indices for estimating postoperative outcomes in pediatric congenital heart surgery.Aortic and radial arterial pressure waveforms were analyzed simultaneously during weaning from CPB in 29 congenital heart surgery. The maximum first derivatives of aortic and radial arterial waveforms were calculated and averaged from 3 consecutive respiratory cycles. We obtained the maximum vasoactive inotropic score during the first 36 postoperative hours, LV ejection fraction, and fractional shortening on transthoracic echocardiography performed within postoperative day 7.A significant difference between aortic and radial dP/dtmax was observed (mean difference 356 mm Hg/s, 44% of averages), and radial dP/dtmax was weakly correlated with aortic dP/dtmax (r =0.373, P = 0.047). Aortic dP/dtmax was significantly associated with the maximum vasoactive inotropic score (P < 0.001), postoperative LV ejection fraction (P = 0.018), and fractional shortening (P = 0.015); however, radial dP/dtmax was not. On Receiver operating characteristic analysis, aortic dP/dtmax had a greater area under the curve than radial dP/dtmax in predicting higher vasoactive inotropic score (0.827 vs 0.673).Immediately after CPB in pediatric congenital heart surgery, radial dP/dtmax may not replace aortic dP/dtmax because of a discrepancy between central and peripheral arterial waveforms. In this critical period, aortic dP/dtmax can be useful to estimate postoperative ventricular function rather than peripherally derived dP/dtmax.

A single strain-based growth law predicts concentric and eccentric cardiac growth during pressure and volume overload

Adult cardiac muscle adapts to mechanical changes in the environment by growth and remodeling (G&R) via a variety of mechanisms. Hypertrophy develops when the heart is subjected to chronic mechanical overload. In ventricular pressure overload (e.g. due to aortic stenosis) the heart typically reacts by concentric hypertrophic growth, characterized by wall thickening due to myocyte radial growth when sarcomeres are added in parallel. In ventricular volume overload, an increase in filling pressure (e.g. due to mitral regurgitation) leads to eccentric hypertrophy as myocytes grow axially by adding sarcomeres in series leading to ventricular cavity enlargement that is typically accompanied by some wall thickening. The specific biomechanical stimuli that stimulate different modes of ventricular hypertrophy are still poorly understood. In a recent study, based on in-vitro studies in micropatterned myocyte cell cultures subjected to stretch, we proposed that cardiac myocytes grow longer to maintain a preferred sarcomere length in response to increased fiber strain and grow thicker to maintain interfilament lattice spacing in response to increased cross-fiber strain. Here, we test whether this growth law is able to predict concentric and eccentric hypertrophy in response to aortic stenosis and mitral valve regurgitation, respectively, in a computational model of the adult canine heart coupled to a closed loop model of circulatory hemodynamics. A non-linear finite element model of the beating canine ventricles coupled to the circulation was used. After inducing valve alterations, the ventricles were allowed to adapt in shape in response to mechanical stimuli over time. The proposed growth law was able to reproduce major acute and chronic physiological responses (structural and functional) when integrated with comprehensive models of the pressure-overloaded and volume-overloaded canine heart, coupled to a closed-loop circulation. We conclude that strain-based biomechanical stimuli can drive cardiac growth, including wall thickening during pressure overload.

Effects of continuous-flow versus pulsatile-flow left ventricular assist devices on myocardial unloading and remodeling

BACKGROUND

Continuous-flow left ventricular assist devices (LVAD) are increasingly used for patients with end-stage heart failure (HF). We analyzed the effects of ventricular decompression by continuous-flow versus pulsatile-flow LVADs on myocardial structure and function in this population.

METHODS AND RESULTS

Sixty-one patients who underwent LVAD implantation as bridge-to-transplant were analyzed (pulsatile-flow LVAD: group P, n=31; continuous-flow LVAD: group C, n=30). Serial echocardiograms, serum levels of brain natriuretic peptide (BNP), and extracellular matrix biomarkers (ECM) were compared between the groups. Myocardial BNP and ECM gene expression were evaluated in a subset of 18 patients. Postoperative LV ejection fraction was greater (33.2±12.6% versus 17.6±8.8%, P<0.0001) and the mitral E/E' was lower (9.9±2.6 versus 13.2±3.8, P=0.0002) in group P versus group C. Postoperative serum levels of BNP, metalloproteinases (MMP)-9, and tissue inhibitor of MMP (TIMP)-4 were significantly lower in group P compared with group C (BNP: 552.6±340.6 versus 965.4±805.7 pg/mL, P<0.01; MMP9: 309.0±220.2 versus 475.2±336.9 ng/dL, P<0.05; TIMP4: 1490.9±622.4 versus 2014.3±452.4 ng/dL, P<0.001). Myocardial gene expression of ECM markers and BNP decreased in both groups; however, expression of TIMP-4 decreased only in group P (P=0.024).

CONCLUSIONS

Mechanical unloading of the failing myocardium using pulsatile devices is more effective as indicated by echocardiographic parameters of systolic and diastolic LV function as well as dynamics of BNP and ECM markers. Therefore, specific effects of pulsatile mechanical unloading on the failing myocardium may have important implications for device selection especially for the purpose of bridge-to-recovery in patients with advanced HF.

Relationship of maximum rate of pressure rise between aorta and left ventricle in pediatric patients. Implication for ventricular-vascular interaction with the potential for noninvasive determination of left ventricular contractility

BACKGROUND

The maximum rate of the ventricular pressure rise (dp/dt(max)) provides a reliable measure of ventricular contractility. However, its estimation requires invasive measurement of left ventricular (LV) pressure, limiting its bedside clinical applicability. In the present study, 2 hypotheses were tested: (1)that the ratio of dp/dt(max) between the aorta (Ao) and LV is consistent among patients despite marked differences in underlying cardiac disease, contractile state and heart rate when vascular mechanical and loading properties are taken into account, and (2)that using such a relationship, LV dp/dt(max) can be estimated from Ao dp/dt(max), potentially providing a method of noninvasive determination of LV contractility.

METHODS AND RESULTS

Data from 30 control children and 45 pediatric patients with various cardiovascular diseases revealed that the characteristic impedance (Zc) and mean arterial pressure were significant determinants of the Ao-LV dp/dt(max) relationship in both control and disease groups. LV dp/dt(max) estimated using the regression obtained in the control children (Ao dp/dt(max/)LV dp/dt(max) = 0.64+1.45*10(-4)*Zc-3.73*10(-3)*MAP, r=0.87) correlated well with the measured LV dp/dt(max) in the disease group, including measurements taken after dobutamine and atrial pacing (r=0.89).

CONCLUSIONS

Ao dp/dt(max) and LV dp/dt(max) are closely correlated through the vascular loading properties and LV dp/dt(max) can be derived from Ao dp/dt(max), which has potential as a noninvasive method of determining LV contractility.

Evaluation of left ventricular short- and long-axis function in severe mitral regurgitation using 2-dimensional strain echocardiography

BACKGROUND

Few data exist on the changes in left ventricular (LV) short- and long-axis function and their usefulness as markers of LV contractile function in patients with chronic, severe mitral regurgitation (MR).

METHODS

We studied 59 patients who had severe MR with an ejection fraction > or =50% and 34 healthy controls. Speckle tracking imaging was performed to measure peak systolic radial (SR(R)), circumferential (SR(C)), and longitudinal strain rates (SR(L)). In all patients, the peak rate of LV pressure rise (peak dP/dt) was measured using a micromanometer-tipped catheter. The patients were subdivided into patients with preserved (group 1, peak dP/dt > or =1,300 mm Hg/s [n = 30]) and depressed (group 2 [n = 29]) contractile function.

RESULTS

SR(L) was significantly depressed in groups 1 and 2 when compared with the control group, but there was no difference between groups 1 and 2. In contrast, SR(R) and SR(C) were depressed only in group 2, whereas there were no differences between the control group and group 1. SR(R) and SR(C) correlated well with peak dP/dt (r = 0.71, P <.001 and r = -0.63, P <.001, respectively), whereas SR(L) did not. These findings suggest that LV long-axis function becomes depressed earlier than short-axis function in the chronic remodeling process.

CONCLUSIONS

Left ventricular short-axis function is a useful marker of LV contractility in patients with chronic, severe MR. Left ventricular long-axis function becomes depressed earlier in the chronic remodeling process. Therefore, evaluation of short-axis as well as long-axis function might be important for better assessment of LV contractile function in these patients.

C-type natriuretic peptide and its relation to non-invasive indices of left ventricular function in patients with chronic heart failure

C-type natriuretic peptide (CNP) significantly increases in chronic heart failure (CHF) patients as a function of clinical severity. Aim of this study was to evaluate in CHF patients the relationship between circulating CNP concentrations and echo-Doppler conventional indices of left ventricular (LV) function as well as less load independent parameters as dP/dt. LV ejection fraction (EF), left ventricular end-diastolic dimension (LVEDD) and LV dP/dt were evaluated together with plasma CNP levels in 38 patients with CHF and in 63 controls. CNP levels resulted significantly higher in CHF patients than in controls (7.19+/-0.59 pg/ml vs. 2.52+/-0.12 pg/ml, p<0.0001). A significant correlation between dP/dt and CNP levels (r=-0.61, p<0.0001) was observed. A good correlation with EF (r=-0.55, p<0.001) and a less significant relation with LVEDD (r=0.316, p<0.05) were also reported. When patients were divided according to dP/dt values a very significant difference in CNP levels was observed: Group I (<600, n=25) vs. Group II (>600, n=13): 8.46+/-0.69 and 4.75+/-0.75 pg/ml, respectively, p<0.001. This is the first study that reports a correlation between CNP and dP/dt in CHF patients, thus suggesting a possible role on cardiac contractility.

Echocardiographic evaluation of hemodynamic parameters

Hemodynamic assessment is a constant and common task in critically ill and injured patients. Correct interpretation of this data is vital to implement the appropriate intervention, if any. It can be difficult to properly interpret derived and measured data from a pulmonary artery catheter for optimal care of these difficult patients. Catheter use remains controversial because some researchers believe there is no clear benefit to the mortality rate. This conundrum will never be settled without a prospective blinded study. However, echocardiography is a vital and reliable monitoring tool to interrogate pressures, ventricular function, ventricular volumes, ventricular interactions, and diastolic compliance. In some institutions, it is used to construct a pressure/volume curve to measure contractility, which is load-dependent. Echocardiography easily can measure intracardiac pressures accurately but in a static fashion, which is one of its major benefits.

Impaired contractile reserve in severe mitral valve regurgitation with a preserved ejection fraction

BACKGROUND

Impaired contractile reserve in chronic MR results from load-independent, myocyte contractile abnormalities.

AIMS

Investigate the mechanisms of contractile dysfunction in chronic mitral valve regurgitation (MR).

METHODS

Mild MR was produced in eight dogs followed by pacing induced left ventricular (LV) dilatation over eight months. In-vivo LV dP/dt was measured at several pacing rates. Contractile function was measured in isolated LV trabeculae and myocytes at several stimulation rates and during changes in extracellular [Ca2+]. Identical studies were performed with six control dogs.

RESULTS

Chronic MR resulted in a preserved ejection fraction with decreased dP/dt (p<0.01). LV trabeculae demonstrated significantly lower developed force and a negative force-frequency relation with chronic MR (p<0.05). Myocytes exhibited a negative shortening-frequency relationship in both groups with a greater decline with chronic MR (p<0.001) paralleled by decreases in peak [Ca2+](i) transients. Increases in extracellular [Ca2+] abrogated the defects in force generation in trabeculae from animals with chronic MR.

CONCLUSION

Even with a preserved EF, chronic severe MR results in a significant reduction in intrinsic contractile function and reserve. Functional impairment was load-independent reflecting a predominant defect in calcium cycling rather than impaired peak force generating capacity due to myofibrillar attenuation.

Atrioventricular delay optimization by doppler-derived left ventricular dP/dt improves 6-month outcome of resynchronized patients

BACKGROUND

Atrioventricular (AV) interval optimization, ensuring the best filling and the abolishment of presystolic mitral regurgitation, is crucial for the efficacy of cardiac resynchronization therapy (CRT). The methods proposed to optimize AV delay have many limitations. The maximum left ventricular pressure derivative (LV dP/dt)--an index of cardiac performance--could provide a clue for AV optimization. DP/dt can be calculated by the Doppler curve of mitral regurgitation jet and it is related to micromanometer-derived dP/dt.

AIM

The aim of this study was to assess whether optimal AV delay, defined as the highest noninvasive dP/dt, may provide clinical and functional benefits in CRT patients.

METHODS

Of 41 consecutive patients, 23 echo Doppler recordings were obtained at AV delays of 60, 80, 100, 120, 140, 160, 180 ms (Group I). Three patients were discarded because of suboptimal Doppler signal. In 15 patients an empiric AV delay of 120 ms was chosen (Group II). Both groups were programmed to atriosynchronous pacing mode and synchronous VV stimulation.

RESULTS

In Group I optimal AV delay was 60 ms in one patient, 80 ms in 6, 100 in 6, 120 in 8, 140 in 2. At 6 months follow-up, Group I showed a significantly lower NYHA class (2.1 +/- 0.1 vs 3 +/- 0.2 P < 0.01) and higher LV ejection fraction (LVEF): 32.1 + 1 versus 27.5 +/- 1.6% (P < 0.05) as compared to Group II.

CONCLUSIONS

Doppler-derived dP/dt for AV delay optimization determines better functional class and LVEF at 6 months follow-up relative to an empiric AV delay program.

Echocardiographic measurement of ventricular function

PURPOSE OF REVIEW

We review new findings concerning ventricular function in patients in intensive care units with shock or unexplained respiratory distress syndrome analyzed using echocardiography.

RECENT FINDINGS

Bedside echocardiography is not only an imaging technique but should be considered as a hemodynamic method. Left-ventricular systolic function can be assessed in daily clinical practice by measuring shortening fraction, fraction area change and ejection fraction. But these indices are dependent on load conditions. Index of myocardial performance can be also used. Rate of left-ventricular pressure increase may be measured from mitral regurgitation. Other indices such a maximal elastance and preload-adjusted maximal power were developed to evaluate myocardial systolic function but are not still used in clinical practice in patients in intensive care. Cardiac output measurement can be calculated easily from aortic annulus diameter and the velocity time integral of aortic blood flow. To complete the assessment of ventricular function, left-ventricular diastolic function and pressure as well as right ventricular size, septal movement and right pressures should be analyzed.

SUMMARY

Using echocardiography the intensivist can examine both the mechanism and the cause of shock or pulmonary edema. It is time to increase the use of this technique in intensive care units.

Improved Papillary Muscle Function Attenuates Functional Mitral Regurgitation in Patients with Dilated Cardiomyopathy After Cardiac Resynchronization Therapy

BACKGROUND

Functional mitral valve regurgitation attenuation after cardiac resynchronization therapy (CRT) in patients with severe heart failure has been attributed to both the increased rate of left ventricular systolic pressure increase and to papillary muscle (PM) recoordinated contraction. We hypothesized that an increase in systolic deformation of the PMs or the adjacent myocardial wall may in part account for this effect, by preventing their outward displacement during systole.

METHODS

We studied by echocardiography 22 patients with moderate/severe functional mitral valve regurgitation and a mean ejection fraction of 18 +/- 4% at baseline and after implantation of a CRT system.

RESULTS

CRT induced a significant reduction of the effective regurgitant orifice area (0.18 +/- 0.11 vs 0.35 +/- 0.17 mm2, P < .001). Strain improved in both PMs and their adjacent walls, although this improvement was significant only in anterolateral PM (-16 +/- 4.7 vs -11 +/- 4.3%, P = .02) and posteromedial PM adjacent wall (-16 +/- 10 vs -8 +/- 4.6%, P = .01).

CONCLUSIONS

CRT acutely reduces the severity of functional mitral valve regurgitation in patients with heart failure and this effect may be in part attributed to improved strain of PM or adjacent wall.

Plasma adrenomedullin relation with Doppler-derived dP/dt in patients with congestive heart failure

BACKGROUND

Increased circulating adrenomedullin (AM) concentration has been reported in congestive heart failure (HF) and considered as a possible marker of cardiac dysfunction.

HYPOTHESIS

The study was undertaken to assess the relationship between circulating AM concentration and left ventricular (LV) functional state, estimated by echo-Doppler techniques in patients with mild to moderate HF and different degrees of LV dysfunction.

METHODS

Plasma AM, B-type natriuretic peptide (BNP), and N-terminal (NT) proBNP levels were measured in 55 patients with HF (New York Heart Association [NYHA] I n = 8, II n = 26, III n = 21) and in 20 controls; dP/dt was calculated by the Doppler tracing of the mitral regurgitation jet.

RESULTS

The study was completed in 51 patients. Adrenomedullin levels were higher than in controls (19.2 +/- 1.4 vs. 13.3 +/- 0.7, p < 0.005) and elevated in proportion to NYHA functional class. B-type natriuretic peptide and NT-proBNP were 344 +/- 67 vs. 12 +/- 2 pg/ml and 2196 +/- 623 vs. 52 +/- 4 pg/ml, respectively (p < 0.0001); dP/dt was better related to AM (r = 0.582, p < 0.001) than to the other peptides. Adrenomedullin was significantly (p < 0.001) different between patients grouped according to the dP/dt cut-off predictive of event-free survival.

CONCLUSIONS

The combination of depressed contractility and increased AM may provide a clue for further characterization of the severity of LV dysfunction in HF, independent of baseline LV ejection fraction.

Acute effects of cardiac resynchronization therapy on functional mitral regurgitation in advanced systolic heart failure

OBJECTIVES

We studied the acute effects of cardiac resynchronization therapy (CRT) on functional mitral regurgitation in heart failure (HF) patients with left bundle branch block (LBBB).

BACKGROUND

Both an decrease [corrected] in left ventricular (LV) closing force and mitral valve tethering have been implicated as mechanisms for functional mitral regurgitation (FMR) in dilated hearts. We hypothesized that an increase in LV closing force achieved by CRT could act to reduce FMR.

METHODS

Twenty-four HF patients with LBBB and FMR were studied after implantation of a biventricular CRT system. Acute changes in FMR severity between intrinsic conduction (OFF) and CRT were quantified according to the proximal isovelocity surface area method by measuring the effective regurgitant orifice area (EROA). Results were compared with the changes in estimated maximal rate of left ventricular systolic pressure rise (LV+dP/dt(max)) and transmitral pressure gradients (TMP), both measured by Doppler echocardiography.

RESULTS

Cardiac resynchronization therapy was associated with a significant reduction in FMR severity. Effective regurgitant orifice area decreased from 25 +/- 19 mm(2) (OFF) to 13 +/- 8 mm(2) (CRT). The change in EROA was directly related to the increase in LV+dP/dt(max) (r = -0.83, p < 0.0001). Compared with OFF, TMP increased more rapidly during CRT, and a higher maximal TMP was observed (OFF 73 +/- 24 mm Hg vs. CRT 85 +/- 26 mm Hg, p < 0.01).

CONCLUSIONS

Functional mitral regurgitation is reduced by CRT in patients with HF and LBBB. This effect is directly related to the increased closing force (LV+dP/dt(max)). The results support the hypothesis that an increase in TMP, mediated by a rise in LV+dP/dt(max) due to more coordinated LV contraction, may facilitate effective mitral valve closure.

Estimation of left ventricular performance through temporal pressure variations measured by MR velocity and acceleration mappings

PURPOSE

To describe a method for assessing pressure variation vs. time (dp/dt) using blood flow acceleration measured by MRI, and to demonstrate its applicability in estimating left ventricular (LV) function.

MATERIALS AND METHODS

The method was tested in vitro using a pulsatile phantom, and a strong correlation was found between transducer and MRI determinations of dp/dt (r = 0.98). Selected aortic flow parameters were then measured in 10 patients and the results were compared with transducer measurements of the LV dp/dt.

RESULTS

The correlation coefficients for the reference estimations of global myocardial function and MRI were 0.59 for aortic velocity, 0.74 for aortic acceleration, and 0.86 for aortic dp/dt.

CONCLUSION

MR measurements of velocity and acceleration within the ascending aorta offer a noninvasive method for determining indices, such as the aortic dp/dt, that are closely correlated with the global myocardial contractility function.

Right ventricular dP/dt/P(max), not dP/dt(max), noninvasively derived from tricuspid regurgitation velocity is a useful index of right ventricular contractility

BACKGROUND

Although right ventricular (RV) contractility is important in determining functional capacity, few quantification methods are clinically available. RV dP/dt(max) can be assessed by Doppler echocardiography by using tricuspid regurgitation (TR) but is not routinely used because of its dependency on a Doppler incident angle and preload. Doppler-derived dP/dt/P(max) is relatively insensitive to preload and theoretically independent of the incident angle. We investigated the clinical feasibility of this index as an RV contractility index.

METHODS

We computed RV dP/dt(max) and dP/dt/P(max) from the TR-derived RV pressure in 68 patients with dominant RV failure (13 in New York Heart Association [NYHA] class I, 33 in class II, 17 in class III, and 5 in class IV). Peak oxygen consumption (peak VO(2)) was measured in 20 patients during a maximal bicycle ergometer test.

RESULTS

dP/dt(max) did not significantly correlate with NYHA class. In contrast, dP/dt/P(max) decreased monotonically with the functional class (r = -0.49, P <.0001), and correlated with peak VO(2) (r = 0.66, P <.002).

CONCLUSION

TR-derived dP/dt/P(max), not dP/dt(max), is a clinically useful index of RV contractility, allowing researchers to account for the functional capacity.

Dicoumarol toxicity in cattle associated with ingestion of silage containing sweet vernal grass (Anthoxanthum odoratum)

A diagnosis of dicoumarol toxicity in a herd of Friesian cattle was made following investigation of the deaths of three mature cows and eleven yearling heifers. Affected stock had been fed wrapped, bailed silage containing approximately 90% sweet vernal grass (Anthoxanthum odoratum). Sweet vernal grass contains coumarin, which can be converted to dicoumarol, a vitamin K antagonist, through the action of moulds. Most deaths were preceded by lethargy, severe anaemia and subcutaneous and internal haemorrhage. Dicoumarol toxicosis was suspected based on clinical signs, necropsy findings and prolonged prothrombin and activated partial thromboplastin times. Dicoumarol analysis of blood from affected animals and silage confirmed the diagnosis. Activated partial thromboplastin time Haemoglobin Packed cell volume Prothrombin time Red cell count

Noninvasive estimation of cardiac systolic function using continuous-wave Doppler echocardiography in dogs with experimental mitral regurgitation

OBJECTIVE

To evaluate the feasibility of noninvasive estimation of cardiac systolic function using transthoracic continuous-wave Doppler echocardiography in dogs with mitral regurgitation.

PROCEDURE

Seven mongrel dogs with experimental mitral regurgitation were used. Left ventriculography and measurement of pulmonary capillary wedge pressure were performed under inhalational anaesthesia. A micromanometer-tipped catheter was placed into the left ventricle and transthoracic echocardiography was carried out. The peak rate of left ventricular pressure rise (peak dP/dt) was derived simultaneously by continuous-wave Doppler and manometer measurements. The Doppler-derived dP/dt was compared with the catheter-measured peak dP/dt in the dogs.

RESULTS

Classification of the severity of mitral regurgitation in the dogs was as follows: 1+, 2 dogs; 2+, 1 dog; 3+, 2 dogs; 4+, 1 dog; and not examined, 1 dog. We were able to derive dP/dt from the transthoracic continuous-wave Doppler echocardiography in all dogs. Doppler-derived dP/dt had a significant correlation with the catheter-measured peak dP/dt (r = 0.90, P < 0.0001).

CONCLUSION

It was demonstrated that transthoracic continuous-wave Doppler echocardiography is a feasible method of noninvasive estimation of cardiac systolic function in dogs with experimental mitral regurgitation and may have clinical usefulness in canine patients with spontaneous mitral regurgitation.

Effects of acute decrease in systemic afterload on accuracy of Doppler-derived left ventricular rate of pressure rise measurement in anesthetized patients

OBJECTIVES

This study was designed to describe exactly the effects of acute decrease in systemic afterload on the accuracy of Doppler-derived left ventricular rate of pressure rise (LV DeltaP/Delta(t)) measurements compared with other routinely used indices of systolic function.

METHODS

Twelve patients scheduled for coronary artery bypass grafting were studied. After induction of anesthesia (T0), afterload was modified by incremental administrations of nicardipine (T1-4). At each step of the procedure, thermodilution-derived cardiac index, left ventricular (LV) fractional area change, and LV DeltaP/Delta(t) were measured, and systemic vascular resistances were calculated.

RESULTS

During the procedure, the systemic vascular resistances decrease averaged 13.4%. Systemic vascular resistances were correlated with LV DeltaP/Delta(t) (r = 0.843, P =.003) but inversely correlated with cardiac index (r = -0.782, P =.005) and LV fractional area change (r = -0.887, P =.003).

CONCLUSION

In conclusion, and inversely to cardiac index or LV fractional area change, LV DeltaP/Delta(t) does not overestimate LV contractility in the presence of an acute decrease in systemic afterload.

Noninvasive assessment of left ventricular isovolumic contraction and relaxation with continuous wave Doppler aortic regurgitant velocity signals: an in vivo validation study

The purpose of this study was to provide fundamental in vivo validation of a method with the use of aortic regurgitant (AR) jet signals recorded with continuous wave (CW) Doppler for assessing left ventricular (LV) isovolumic contraction and relaxation. Preliminary studies have suggested that analysis of CW Doppler AR velocity signals permits the estimation of LV positive and negative dP/dt. We studied 19 hemodynamically different states in 6 sheep with surgically induced chronic aortic regurgitation. CW AR velocity spectra and high-fidelity LV and aortic pressures were recorded simultaneously. Rates of LV pressure rise and fall (RPR and RPF) were calculated by determining the time interval between points at 1 m/s and 2.5 m/s in the deceleration and acceleration slopes of the CW Doppler AR velocity envelope (corresponding to a pressure change of 21 mm Hg). RPR and RPF calculated by CW Doppler analysis for each state were compared with the peak positive dP/dt and negative dP/dt, obtained from the corresponding high-fidelity LV pressure curve, respectively. The LV peak positive and negative dP/dt derived by catheter ranged from 817 to 2625 mm Hg/s and from 917 to 2583 mm Hg/s, respectively. Multiple regression analysis showed that Doppler RPR correlated well with catheter peak positive dP/dt (r = 0.93; mean differences, -413 +/- 250 mm Hg/s). There was also good correlation and agreement between Doppler RPF and the catheter peak negative dP/dt (r = 0.89; mean difference, -279 +/- 239 mm Hg/s). Both Doppler-determined RPR and RPF underestimated their respective LV peak dP/dt. CW Doppler AR spectra can provide a reliable noninvasive estimate of LV dP/dt and could be helpful in the serial assessment of ventricular function in patients with aortic regurgitation.

Relationship between doppler-derived left ventricular diastolic function and exercise capacity in patients with myocardial infarction

Doppler echocardiographic indices of left ventricular (LV) diastolic function are widely used to evaluate the cardiac function of patients with cardiac disease. However, there have been few reports about the relationship between Doppler indices and exercise capacity and so 44 patients with myocardial infarction were investigated by cardiopulmonary exercise testing and 2-D and Doppler echocardiography. Diastolic performance was assessed using Doppler transmitral flow velocity and pulmonary venous flow velocity. The ratio of peak E wave velocity and peak A wave velocity (E/A) correlated with peak oxygen consumption (peak Vo2) (R=0.72), and there was a negative correlation between the deceleration time of E velocity (Dct) and peak Vo2 or anaerobic threshold (AT) (R=-0.65, -0.62, respectively). The ratio of peak S wave velocity and peak D wave velocity (S/D) negatively correlated with peak Vo2 (R=-0.58). Left ventricular ejection fraction did not correlate to exercise capacity. These results suggest that the Doppler echocardiographic indices of LV diastolic function correlate with exercise capacity in patients with mild cardiac dysfunction.

Doppler-derived dP/dt and -dP/dt predict survival in congestive heart failure

OBJECTIVES

The purpose of this study was to evaluate the ability of novel Doppler indices of left ventricular (LV) systolic and diastolic function to predict survival in patients with congestive heart failure (CHF).

BACKGROUND

Congestive heart failure is associated with an increased risk of death or cardiac transplantation, yet techniques to predict survival are limited.

METHODS

Doppler-derived dP/dt and - dP/dt were determined prospectively from the continuous-wave Doppler spectrum of the mitral regurgitation jet (dP/dt = 32/time between 1 and 3 m/s; -dP/dt = 32/time between 3 and 1 m/s) in 56 patients with chronic CHF (age, 60 +/- 15 years; LV ejection fraction, 23 +/- 9%). Baseline clinical and echocardiographic variables were also obtained, and clinical follow-up was performed in all patients.

RESULTS

Twenty-four patients experienced a primary event of cardiac death (n = 15), United Network for Organ Sharing status I (inotrope-dependent) heart transplant (n = 3) or urgent implantation of a LV assist device (n = 6). Doppler-derived dP/dt (dichotomized to > or = or <600 mm Hg/s; p = 0.0002) and -dP/dt (trichotomized to <450, 450 to 550 and >550 mm Hg/s; p = 0.0001) predicted event-free survival, as did Doppler-derived risk groups determined by the combination of the two (low risk, dP/dt > or = 600; intermediate risk, dP/dt < 600 and -dP/dt > or = 450; high risk, dP/dt < 600 and -dP/dt < 450; p = 0.0001). Multivariable analysis revealed Doppler-derived risk groups, intravenous inotrope requirement and blood urea nitrogen as significant independent predictors of outcome.

CONCLUSION

New Doppler indices of dP/dt, - dP/dt and risk groups defined by the combination of dP/dt and -dP/dt predict event-free survival in patients with CHF.

Transthoracic and transesophageal echocardiography in the hemodynamic assessment of patients with congestive heart failure

All methods for estimating the severity of heart failure, such as clinical and radiographic examination, measures of ventricular performance, and exercise capacity, when used independently, have major limitations. Echocardiography can be used, not only to assess left-ventricular ejection fraction but also other determinants of prognosis (i.e., left-ventricular size and shape, estimation of left atrial and pulmonary artery pressures, right side involvement). The availability of continuous-wave Doppler has permitted us to evaluate pulmonary artery systolic pressure from tricuspid regurgitation, and this contributes to additional powerful data. In long-standing heart failure, pulmonary artery wedge pressure is a predictor of survival, and aggressive therapy to reduce wedge pressure improves survival. Noninvasive estimation of left-atrial pressure and left-ventricular filling pressure have been attempted by continuous-wave Doppler echocardiography in patients with heart failure and mitral regurgitation and by tissue Doppler imaging at the mitral annulus level. A significant relation has been reported between profiles of pulmonary venous flow and left-atrial pressure, but pulmonary venous flow indexes can be better assessed by transesophageal echocardiography (TEE) in terms of detection rate. It has recently been recognized that TEE can provide valuable information on intracardiac hemodynamics and ventricular function. Two-dimensional evaluation of ventricular function and pulsed- and continuous-wave Doppler recordings from the pulmonary artery, pulmonary vein, and mitral inflow are combined to provide these data, which are both qualitative and quantitative, and permit estimation of ventricular ejection fraction, left-atrial pressure, and cardiac output. It would be important to be able to stratify patients with congestive heart failure according to groups with the highest risk for early death because heart transplantation or aggressive medical treatment could be specifically applied to this population. Serial echocardiographic evaluations of the classic variables of systolic left-ventricular function as well as Doppler transmitral flow may be useful in monitoring the progression of the disease and the effects of medical treatment. The degree of pulmonary hypertension is independently associated with the restrictive left-ventricular diastolic filling pattern and with the degree of functional mitral regurgitation. Future studies on the impact of these hemodynamic variables on the outcome of patients with left-ventricular dysfunction are desirable.

Doppler-derived left ventricular rate of pressure rise determination in presence of severe acute mitral regurgitation in pigs

Doppler-derived left ventricular (LV) rate of pressure rise (Dop LV DeltaP/Deltat) is described as an index of LV performance in the presence of mitral regurgitation (MR). This study was designed to define more accurately the accuracy of the method in the presence of severe MR. Ten pigs were anesthetized and monitored. MR was gradually created. At each grade of MR, preload was manipulated with the intent of modifying LV end-diastolic area value within a range of +/-20%. Concurrently, the mean left atrial pressure (LAP) was recorded, MR was quantified by the mitral to aortic velocity-time integral ratio (mitroaortic VTI ratio), Dop LV DeltaP/Deltat was calculated, and peak LV dP/dt was derived from LV catheterism data. During the procedure Dop LV DeltaP/Deltat gradually underestimated peak LV dP/dt. This difference was correlated to the mean LAP (P < 10(-5)) and mitroaortic VTI ratio (P < 10(-5)) and became clinically significant when the mean LAP was superior to 21 mm Hg.

Mechanism of dynamic regurgitant orifice area variation in functional mitral regurgitation: physiologic insights from the proximal flow convergence technique

OBJECTIVES

We used the Doppler proximal flow convergence technique as a physiologic tool to explore the effects of the time courses of mitral annular area and transmitral pressure on dynamic changes in regurgitant orifice area.

BACKGROUND

In functional mitral regurgitation (MR), regurgitant flow rate and orifice area display a unique pattern, with peaks in early and late systole and a midsystolic decrease. Phasic changes in both mitral annular area and the transmitral pressure acting to close the leaflets, which equals left ventricular-left atrial pressure, have been proposed to explain this dynamic pattern.

METHODS

In 30 patients with functional MR, regurgitant orifice area was obtained as flow (from M-mode proximal flow convergence traces) divided by orifice velocity (v) from the continuous wave Doppler trace of MR, transmitral pressure as 4v(2), and mitral annular area from two apical diameters.

RESULTS

All patients had midsystolic decreases in regurgitant orifice area that mirrored increases in transmitral pressure, while mitral annular area changed more gradually. By stepwise multiple regression analysis, both mitral annular area and transmitral pressure significantly affected regurgitant orifice area; however, transmitral pressure made a stronger contribution (r2 = 0.441) than mitral annular area (added r2 = 0.008). Similarly, the rate of change of regurgitant orifice area more strongly related to that of transmitral pressure (r2 = 0.638) than to that of mitral annular area (added r2 = 0.003). A similar regurgitant orifice area time course was observed in four patients with fixed mitral annuli due to Carpentier ring insertion.

CONCLUSIONS

In summary, the time course and rate of change of regurgitant orifice area in patients with functional MR are predominantly determined by dynamic changes in the transmitral pressure acting to close the valve. Thus, although mitral annular area helps determine the potential for MR, transmitral pressure appears important in driving the leaflets toward closure, and would be of value to consider in interventions aimed at reducing the severity of MR.

Doppler echocardiography. I. Pulsed-wave and continuous-wave examinations

Doppler echocardiography is a specialized processing of cardiac ultrasound that is characterized by a continuously updated display of blood velocity during the cardiac cycle. Doppler examinations, which include color-coded Doppler echocardiography, pulsed-wave examination, and continuous-wave studies, are readily applicable to veterinary patients.

[A simplified method of continuous-wave Doppler noninvasive assessment of ventricular relaxation in mitral insufficiency]

INTRODUCTION AND OBJECTIVES

The minimum value of dP/dT is a parameter of diastolic function that can be estimated noninvasively by analyzing the profile of velocity of the mitral regurgitant jet, recorded by continuous-wave Doppler. This estimation requires a complex analysis of the curves that impedes its practical use. Our objective was to validate a simplified method to estimate noninvasively the value of dP/dTmin when mitral regurgitation exists. We calculated the pendient of the profile of velocity of the curve of mitral regurgitation during its deceleration, between 3 and 1.5 m/s, an interval that defines a difference in pressure using the formula delta p = (4v2(1) - 4v2(2)). We divided this interval by the time needed by the jet to decelerate from 3 to 1.5 m/s, obtaining the rate of pressure decay, in mmHg/s.

METHODS

We provoked mitral regurgitation in five pigs and registered dP/dT and the curve velocity of mitral regurgitation simultaneously, by micromanometer-tipped catheter and continuous-wave Doppler, respectively. The rate of pressure decay was calculated on the mitral regurgitation curve.

RESULTS

We obtained 29 simultaneous registers. The coefficient for the correlationship between dP/dT and the rate of pressure decay was with an r value of 0.62 (p < 0.0001). The rate of pressure decay underestimated systematically the value of dP/dT. Intra and interobserver variability of TDP was 9 and 11%, respectively.

CONCLUSIONS

This study validates a simplified method to estimate dP/dT noninvasively, with acceptable correlation with invasive measurements and adequate reproducibility.

Doppler echocardiographic assessment and cardiac gene expression analysis of the left ventricle in myocardial infarcted rats

The purpose of this study was to examine cardiac geometry and function by Doppler echocardiography and to analyze mRNA expression of cardiac phenotype and extracellular matrix in myocardial infarcted rats. Doppler echocardiograms and hemodynamics were measured 2 weeks after myocardial infarction (MI). mRNA levels in the non-infarcted left ventricle (LV) and infarct site were measured by Northern blot analysis. LV internal diastolic dimension was greater in infarcted (MI) than in sham-operated rats (control) (MI 7.2+/-0.3 mm vs control 4.6+0.3 mm, p<0.01). The fractional shortening decreased in MI rats (MI 32+4% vs control 61+/-3%, p<0.01). Peak early filling velocity increased in MI rats (MI 91+/-5 cm/sec vs control 72+/-4 cm/sec, p<0.05), and deceleration rate of the early filling wave was more rapid in rats with MI (MI 25.1+/-2.8 m/sec2 vs control 12.4+/-1.7 m/sec2, p < 0.01). Late filling velocity decreased (MI 16+/-3 cm/sec vs control 35+/-6 cm/sec, p <0.05), resulting in a marked increase in the ratio of early filling to late filling (MI 7.1+/-1.2 vs control 2.5+/-0.4, p<0.01). mRNA levels for beta-myosin heavy chain (beta-MHC), a-skeletal actin, atrial natriuretic polypeptide (ANP), collagen types I and III, and matrix metalloproteinase 2 (MMP-2) in the non-infarcted LV increased significantly by 1.8-, 2.4-, 4.7-, 2.6-, 2.1- (all p<0.01) and 1.4-fold (p<0.05), respectively, compared with sham-operated myocardium. In the infarct site, mRNA levels for transforming growth factor (TGF)-beta1, collagen types I and III, and MMP-2 significantly increased by 3.2-, 11.0-, 9.7-, and 6.3-fold (all p<0.01), respectively, compared with sham-operated myocardium. Myocardial infarcted rat was characterized by cavity dilation and marked abnormalities of systolic and diastolic function, accompanied by a shift of myocytes to fetal phenotype and activation of collagen genes in the non-infarcted myocardium.

Preload and incident angle independent index of left ventricular contractility determined by continuous wave Doppler echocardiography

Although left ventricular dP/dtmax can be accurately assessed using Doppler echocardiography, the fact that Doppler-derived dP/dtmax depends both on preload and Doppler incident angle limits its clinical value. We investigated the clinical usefulness of Doppler-derived (dP/dtmax)/IP (IP, isovolumic pressure), which is known to be relatively insensitive to preload and theoretically independent of the incident angle in 9 subjects. We conclude that Doppler-derived (dP/dtmax)/IP is relatively insensitive to both the incident angle and preload. In addition to its noninvasiveness, these unique features makes it very attractive as a clinical index of ventricular contractility.

Rates of left ventricular isovolumic pressure rise and fall from the aortic regurgitation velocity signal: description of the method and validation in human beings

BACKGROUND

Aortic regurgitation results from a pressure gradient across the aortic valve during left ventricular (LV) isovolumic relaxation, LV filling, and isovolumic contraction periods. Assuming the applicability of the simplified Bernoulli equation to this pressure-flow relation and constancy of aortic pressure during LV isovolumic relaxation and contraction periods, one can theoretically obtain estimates of the rates of LV isovolumic pressure fall and rise (deltaP/delta t) from the aortic regurgitation (AR) velocity signal.

METHODS AND RESULTS

Mitral regurgitation (MR) and AR signals were recorded by using the continuous wave Doppler technique in 26 patients with combined mitral and aortic regurgitant lesions. The LV negative deltaP/delta t was obtained by dividing the time taken for the AR velocity to rise from 1 m/sec to 2.5 m/sec into 21 mm Hg, which is the estimated LV pressure drop between these points. In a similar fashion, the LV positive deltaP/delta t was obtained between 2.5 m/sec and 1 m/sec of the fast decelerating portion of the AR signal. The LV negative deltaP/delta t by the AR method ranged from 420 to 3500 mm Hg/sec and correlated well with that obtained by the MR method obtained in a blinded fashion (r = 0.95, p < 0.0001). The mean (SD) difference between the two methods was 30 (129) mm Hg/sec. Similarly, the LV positive deltaP/delta t by the AR method (range 420 to 2625 mm Hg/sec) correlated closely with that obtained by the MR method (r = 0.93, p < 0.0001), with the mean (SD) difference between the two methods being 38 (138) mm Hg/sec.

CONCLUSIONS

Preliminary data presented in this study indicate the feasibility of obtaining a reliable estimate of LV positive and negative deltaP/delta t from the AR velocity profile. Thus the examination of the AR signal may give valuable insights into both LV systolic and diastolic functions.

Assessment of left ventricular systolic wall motion velocity with pulsed tissue Doppler imaging: comparison with peak dP/dt of the left ventricular pressure curve

To assess the usefulness of the tissue Doppler imaging variables for the evaluation of left ventricular (LV) systolic function, we compared variables obtained by the pulsed Doppler method with the LV ejection fraction (%EF) and the maximum value for the first derivative of LV pressure (peak dP/dt). We examined 65 patients, including 15 patients with noncardiac chest pain, 15 with ischemic heart disease, 15 with dilated cardiomyopathy, 10 with hypertensive heart disease, and 10 with asymmetric septal hypertrophic cardiomyopathy. The subendocardial systolic wall motion velocity patterns were recorded for LV posterior wall and ventricular septum in the parasternal LV long-axis view. The peak dP/dt was significantly lower in the hypertensive heart disease, hypertrophic cardiomyopathy, and dilated cardiomyopathy groups. The peak systolic velocity was lower and the time from the electrocardiographic Q wave to the peak of the systolic wave for the posterior wall was longer in the hypertensive heart disease (5.9 +/- 0.5 cm/sec and 215 +/- 21 msec, respectively), hypertrophic cardiomyopathy (6.2 +/- 0.9 cm/sec and 217 +/- 17 msec, respectively), and dilated cardiomyopathy (5.2 +/- 0.8 cm/sec and 235 +/- 26 msec, respectively) groups than in the noncardiac chest pain (7.7 +/- 0.9 cm/sec and 187 +/- 24 msec, respectively) and the ischemic heart disease (7.6 +/- 0.8 cm/sec and 184 +/- 22 msec, respectively) groups. In all groups, the peak systolic velocity and the time from the electrocardiographic Q wave to the peak of the systolic wave for the posterior wall correlated directly and inversely, respectively, with the %EF (r = 0.59, p < 0.0001; r = -0.59, p < 0.0001) and the peak dP/dt (r = 0.75, p < 0.0001; r = -0.68, p < 0.0001). Both tissue Doppler variables for the ventricular septum did not correlate with the %EF but roughly correlated with peak dP/dt. We conclude that the systolic LV wall motion velocity parameters obtained by pulsed tissue Doppler imaging may be useful for noninvasive evaluation of global LV systolic function in patients with no regional asynergy.

Accurate noninvasive estimation of left ventricular end-diastolic pressure: comparison with catheterization

We evaluated the accuracy of a new Doppler-based method using the mitral regurgitant velocity at the time of aortic valve opening for the noninvasive estimation of left ventricular end-diastolic pressure. Sixty unselected patients were studied immediately before routine catheterization. Invasive left ventricular end-diastolic pressure was obtained using a fluid-filled pig-tail catheter. Noninvasive estimation of left ventricular pressure at aortic valve opening was taken as systemic diastolic pressure using an automated cuff. Noninvasive left ventricular end-diastolic pressure was calculated as diastolic blood pressure--4 x (mitral regurgitant velocity at aortic opening)2. Those making noninvasive determinations were blinded to catheterization results. An adequate mitral regurgitant Doppler recording was obtained in 24 patients (40%). In patients with a left ventricular end-diastolic pressure greater than 15 mm Hg the yield was 65%. Left ventricular end-diastolic pressures ranged from 4 mm Hg to 30 mm Hg. Bland and Altman analysis revealed no systematic bias and close agreement was found, with individual discrepancies not exceeding 5 mm Hg.