Effect of increasing heart rate on Doppler indices of left ventricular performance in healthy men

Exercise alters cardiac function independent of acute systemic inflammation in healthy men

Acute elevations in inflammatory cytokines have been demonstrated to increase aortic and left ventricular stiffness and reduce endothelial function in healthy subjects. As vascular and cardiac functions are often transiently reduced following prolonged exercise, it is possible that cytokines released during exercise may contribute to these alterations. The a priori aims of this study were to determine whether vaccine-induced increases in inflammatory cytokines would reduce vascular and left ventricular function, whether vascular alterations would drive cardiac impairments, and whether this would be potentiated by moderate exercise. In a randomized crossover fashion, 16 male participants were tested under control (CON) and inflammatory (INF) conditions, wherein INF testing occurred 8 h following administration of an influenza vaccine. On both days, participants underwent measures of echocardiography performed during light cycling (stress-echocardiography), carotid-femoral pulse wave velocity (cf-PWV), and superficial femoral flow-mediated dilation (FMD) before and after cycling for 90 min at ∼85% of their first ventilatory threshold. IL-6 increased significantly (Δ1.9 ± 1.3 pg/mL, P < 0.001), whereas TNFα was nonsignificantly augmented (Δ0.05 ± 0.11 pg/mL, P = 0.09), 8 h following vaccination. Vascular function was unaltered following cycling or inflammation (all P > 0.05). The use of echocardiography during light cycling revealed cardiac alterations traditionally expected to occur only with greater exercise loads, with reduced systolic (e.g., longitudinal strain CON: Δ3.3 ± 4.4%, INF: Δ1.7 ± 2.7%, P = 0.002) and diastolic function (e.g., E/A ratio CON: Δ-0.32 ± 0.34 a.u., INF:Δ-0.25 ± 0.27 a.u., P = 0.002) following cycling, independent of inflammation. The vaccine reduced stroke volume (SV) (main effect of condition P = 0.009) before-and-after cycling. These findings indicate that reduced cardiac function following exercise occurs largely independent of additional inflammatory load.NEW & NOTEWORHTHY This experimental investigation sought to determine the role of inflammation on the occurrence of cardiovascular alterations following exercise. Despite successfully stimulating systemic inflammation via vaccination, vascular and cardiac functions were largely unaltered. Prolonged exercise itself reduced cardiac function assessed via echocardiography performed during light exercise stress. This demonstrates a potential advantage to using stress-echocardiography for measuring exercise-induced cardiac fatigue, as typical resting measures following similar exercise exposures commonly suggest no effect.

Alterations in Cardiac Function Following Endurance Exercise Are Not Duration Dependent

Cardiac function has been shown to transiently decrease following prolonged exercise, with greater durations related to increased impairment. However, the prospective assessment of exercise duration on cardiac performance is rare, and the influence of relative exercise intensity is typically not assessed in relation to these changes. The aim of this study was to determine whether progressively longer running distances over the same course would elicit greater cardiac impairment. The present investigation examined cardiac alterations in 49 athletes, following trail-running races of 25, 50, 80, and 160 km, performed on the same course on the same day. Echocardiography, including conventional and speckle tracking imaging, was performed with legs-raised to 60° to mitigate alterations in preload both pre- and post-race. Race-intensities were monitored via heart rate (HR). Following the races, mean arterial pressure (Δ−11 ± 7 mmHg, P < 0.0001), and HR (Δ19 ± 14 bpm, P < 0.0001) were altered independent of race distance. Both left and right ventricular (LV and RV) diastolic function were reduced (ΔLV E/A −0.54 ± 0.49, P < 0.0001; ΔRV A’ + 0.02 ± 0.04 m/s, P = 0.01) and RV systolic function decreased (ΔTAPSE −0.25 ± 0.9 cm, P = 0.01), independent of race distance. Cardiac impairment was not apparent using speckle tracking analysis with cubic spline interpolation. While race duration was unrelated to cardiac alterations, increased racing HR was related to greater RV base dilation (r = −0.37, P = 0.03). Increased time spent at higher exercise intensities was related to reduced LV ejection fraction following 25 km (r = −0.81, P = 0.03), LV systolic strain rate following 50 km (r = 0.59, P = 0.04), and TAPSE (r = −0.81, P = 0.03) following 80 km races. Increased running duration did not affect the extent of exercise-induced cardiac fatigue, however, intensity may be a greater driver of cardiac alterations.

Transient atrial mechanical dysfunction assessed in acute phase of embolic stroke of undetermined source

BACKGROUND AND PURPOSE

Paroxysmal atrial fibrillation (PAF) has been suggested as a major cause of embolic stroke of undetermined source (ESUS). Transient atrial mechanical dysfunction (stunning) frequently occurs after conversion of atrial fibrillation to sinus rhythm. The study aim was to determine if reversible atrial mechanical dysfunction in ESUS could help elucidate the mechanism of stroke.

METHODS

Eighty-five consecutive patients with acute ischemic stroke were enrolled according to the following inclusion criteria: [1] ≥55 years old; [2] normal sinus rhythm upon admission; [3] no apparent embolic source; and [4] transthoracic echocardiographic evaluation had been performed in both the early phase (<72 h) and late phase (>7 days) after stroke onset. There were 27 patients in the lacunar or atherothrombotic infarction group (controls), 22 in the PAF group, and 36 in the ESUS group. To determine atrial stunning, transmitral flow velocity profiles (Doppler peak E- [early diastolic] and A- [atrial systolic] waves) were obtained.

RESULTS

In the early phase, an E/A velocity ratio ≥ 1.0 was less common in the control group (1 patient, 3.7%) than in the PAF group (19 patients, 86.4%; p < 0.001) and ESUS group (10 patients, 27.8%; p < 0.05). In the late phase, the E/A ratio decreased to less than 1.0 in six patients (31.6%) who had PAF and in eight patients (80.0%) who had ESUS.

CONCLUSION

Transient atrial mechanical dysfunction could be a helpful finding for elucidating the stroke mechanism in patients with ESUS, and early echocardiographic assessment could improve its detection.

Age-Dependence of Flow Homeostasis in the Left Ventricle

Background: Intracardiac flow homeostasis requires avoiding blood stasis and platelet activation during its transit through the cardiac chambers. However, the foundations of intraventricular blood washout and its exposure to shear stresses have been poorly addressed. We aimed to characterize and quantify these features in a wide population of healthy subjects and assess the relationships of these indices with age. Methods: We used color-Doppler echocardiography and custom post-processing methods to study 149 healthy volunteers from 26 days to 80 years old. From the intraventricular flow-velocity fields we obtained personalized maps of (1) the residence time of blood in the LV, and (2) the shear index, a metric accounting for the strongest occurrence of shear stresses inside the chamber. From these maps we derived quantitative indices of the overall intraventricular blood washout and shear exposure. We addressed the age-dependence of these indices and analyzed their relationship with age-related changes in filling-flow. Results: The entire intraventricular blood pool was replaced before 8 cycles. Average residence time of blood inside the LV was <3 cycles in all subjects and followed an inverse U-shape relationship with age, increasing from median (IQR) of 1.0 (0.7 to 1.2) cycles in the 1st year of life to 1.8 (1.4-2.2) cycles in young adults (17-30 years old), becoming shorter again thereafter. Shear index showed no relation with age and was bounded around 20 dyn·s/cm2. Regions with the longest residence time and highest shear index were identified near the apex. Differences in the degree of apical penetration of the filling waves and the duration of the late-filling phase explained the age-dependence of residence time (R adj 2 = 0.48, p < 0.001). Conclusions: In average, blood spends 1 to 3 beats inside the LV with very low shear stress rates. The apical region is the most prone to blood stasis, particularly in mid-aged adults. The washout of blood in the normal LV is age-dependent due to physiological changes in the degree of apical penetration of the filling waves.

Inotropic and lusitropic effects of levosimendan and milrinone assessed by strain echocardiography-A randomised trial

BACKGROUND

We compared the direct inotropic and lusitropic effects of two inodilators, milrinone and levosimendan in patients after aortic valve replacement for aortic stenosis.

METHODS

In this randomised, blinded study, 31 patients with normal LV function, were randomised to either levosimendan (0.1 and 0.2 μg/kg/min, n = 15) or milrinone (0.4 and 0.8 μg/kg/min, n = 16) after aortic valve replacement. The effects on LV performance, LV strain, systolic (SR-S) and early diastolic (SR-E) strain rate were assessed by a pulmonary artery catheter and transoesophageal two-dimensional speckle tracking echocardiography of the LV inferior wall. To circumvent the inodilator-induced hemodynamic changes on LV systolic and diastolic deformation, central venous pressure (CVP), systolic artery pressure (SAP), and heart rate were maintained constant by colloid infusion, phenylephrine-induced vasoconstriction and atrial pacing, respectively, during drug infusion.

RESULTS

Both inotropic agents induced a dose-dependent increase in cardiac index and stroke volume index by approximately 20% at the highest infusion rates with no differences between groups (P = .139 and .249, respectively). CVP, pulmonary capillary wedge pressure, SAP and heart rate were maintained constant in both groups. LV strain and SR-S increased with both agents, dose-dependently, by 17%-18% and 25%-30%, respectively, at the highest infusion rates, with no difference between groups (P = .434 and .284, respectively). Both agents improved early LV relaxation with no differences between groups (P = .637). At the higher doses, both agents increased SR-E by 30%.

CONCLUSIONS

At clinically relevant infusion rates and a certain increase in LV performance the direct inotropic and lusitropic of milrinone and levosimendan were comparable.

Early change in left atrial function in patients treated with anthracyclines assessed by real-time three-dimensional echocardiography

Real-time three-dimensional echocardiography(RT-3DE) has allowed a better assessment of LA volumes and function. We sought to assess the early change in left atrial size and function in patients treated with anthracyclines using RT-3DE. 61 patients aged 44.9 ± 11.9 years with large B-cell non-Hodgkin lymphoma treated with doxorubicin were studied. Blood collection and echocardiography were performed at baseline and 1 day after completion of the chemotherapy. Global longitudinal strain (GLS), maximum, minimum and pre-atrial contraction LA volumes were measured and reservoir, conduit and booster pump function were assessed. Despite normal LVEF, passive emptying percent of total emptying (0.51 ± 0.14 vs. 0.40 ± 0.12, P < 0.001) and passive emptying index (0.29 ± 0.10 vs. 0.23 ± 0.06, P < 0.001) were remarkably reduced compared to baseline values, while active emptying percent of total emptying (0.49 ± 0.14 vs. 0.60 ± 0.12, P < 0.001) and active emptying index (0.41 ± 0.16 vs. 0.47 ± 0.16, P = 0.048) were increased. GLS (−21.64 ± 2.83 vs. −17.30 ± 2.50) was markedly reduced, cTnT levels was elevated from 0.005 ± 0.004 to 0.020 ± 0.026 ng/mL at the completion of chemotherapy (P all  < 0.001). Early LA functional change occur after doxorubicin exposure in patients with preserved LVEF, which could be detected by RT-3DE.

Increased systemic Th17 cytokines are associated with diastolic dysfunction in children and adolescents with diabetic ketoacidosis

Diastolic dysfunction suggestive of diabetic cardiomyopathy is established in children with T1DM, but its pathogenesis is not well understood. We studied the relationships of systemic inflammatory cytokines/chemokines and cardiac function in 17 children with T1DM during and after correction of diabetic ketoacidosis (DKA). Twenty seven of the 39 measured cytokines/chemokines were elevated at 6-12 hours into treatment of DKA compared to values after DKA resolution. Eight patients displayed at least one parameter of diastolic abnormality (DA) during acute DKA. Significant associations were present between nine of the cytokine/chemokine levels and the DA over time. Interestingly, four of these nine interactive cytokines (GM-CSF, G-CSF, IL-12p40, IL-17) are associated with a Th17 mediated cell response. Both the DA and CCL7 and IL-12p40, had independent associations with African American patients. Thus, we report occurrence of a systemic inflammatory response and the presence of cardiac diastolic dysfunction in a subset of young T1DM patients during acute DKA.

Effect of Preload Augmentation on Pulsed Wave and Tissue Doppler Echocardiographic Indices of Diastolic Function After a Marathon

BACKGROUND

The mechanisms underlying alterations in left ventricular diastolic function after a marathon are unknown and may be a consequence of a reduced preload.

OBJECTIVE

We sought to assess the effect of preload augmentation through passive leg elevation (PLE) on echocardiographic indices of diastolic function after a marathon.

METHODS

Fourteen trained participants (13 male) were echocardiographically assessed before and after a marathon in the supine position and during PLE. Diastolic function was measured via conventional Doppler, color M-mode, and tissue Doppler echocardiography. Early and late transmitral filling velocities (E and A, respectively), flow propagation velocity of early filling, and basal early and late left ventricular wall velocities (E' and A', respectively) were obtained.

RESULTS

The E/A ratio, flow propagation velocity of early filling, and the E'/A' ratio decreased by 31%, 24%, and 32%, respectively (P < .05), after marathon running. Postrace PLE returned E to baseline and increased E/A compared with postrace supine (P < .05). However, E/A remained depressed compared with baseline as a result of the persistent elevation in A. Postrace PLE caused Vp to return to baseline; mean E' also increased (9%, P < .05), but did not return to resting levels. Mean A' was unaffected by postrace PLE, therefore, E'/A' was unchanged postrace despite PLE.

CONCLUSION

Postexercise alterations in Doppler indices of diastolic function can be partially explained by a reduction in preload. However, data from tissue Doppler echocardiography indicate that there is an intrinsic impairment in myocardial relaxation after marathon running.

Adaptive mechanisms of left ventricular diastolic function to the physiologic load of pregnancy

BACKGROUND

Pregnancy is associated with marked alteration in cardiovascular hemodynamics. Recent reports have characterized the effects on cardiac systolic function. Little has been written on the influences of loading conditions on Doppler measures of diastolic function during pregnancy.

HYPOTHESIS

Stage of pregnancy has an impact on Doppler indices of diastolic function independent of loading conditions, systolic function, and heart rate.

METHOD

Thirty healthy women were prospectively evaluated by serial echocardiography and Doppler examinations at six time periods: 10-12, 18-20, 28-30, 36-38 weeks gestation, 2-4 and 12-14 weeks postpartum. The related effects on indices of diastolic function and its interaction with load, heart rate, mass, and systolic function were determined.

RESULTS

Compared with the nonpregnant state, early (E) velocity increased (0.7+/-0.1-0.9+/-0.1 m/s, p = 0.0001), peaking at 18 weeks and returning to normal levels during late pregnancy. Atrial phase (A) velocity peaked at 18 weeks (0.48+/-0.12-0.60+/-0.13 m/s, p = 0.0001), remaining high throughout the rest of pregnancy. Consequently, the EWA ratio fell significantly during late pregnancy, from 1.9+/-0.4 to 1.4+/-0.3 (p = 0.02). In addition, mean acceleration was significantly increased in early pregnancy with a peak at 18 weeks (7.4+/-1.3 m/s2), returning to nonpregnant level at term (5.7+/-1.4 m/s2, p = 0.0001). Generalized estimating equation using multivariate regression analysis demonstrated that rising heart rate and stroke volume index had an independent effect on A velocity, and that contractility and preload had an independent effect on E velocity. Pregnancy itself had an independent influence on early filling, not explained by the other parameters.

CONCLUSIONS

During normal pregnancy, there is a reversible shift in transmitral flow velocities from early to late filling with a decrease in acceleration, consistent with an increase in ventricular compliance. Changes in heart rate, preload, and contractility, as well as stage of pregnancy influence this alteration.

What parameters affect left ventricular diastolic flow propagation velocity? In vitro studies using color M-mode Doppler echocardiography

BACKGROUND

Insufficient data describe the relationship of hemodynamic parameters to left ventricular (LV) diastolic flow propagation velocity (Vp) measured using color M-mode Doppler echocardiography.

METHODS

An in vitro LV model used to simulate LV diastolic inflow with Vp measured under conditions of varying: 1) Stroke volume, 2) heart rate (HR), 3) LV volume, 4) LV compliance, and 5) transmitral flow (TMF) waveforms (Type 1: constant low diastasis flow and Type 2: no diastasis flow).

RESULTS

Univariate analysis revealed excellent correlations of Vp with stroke volume (r = 0.98), LV compliance (r = 0.94), and HR with Type 1 TMF (r = 0.97). However, with Type 2 TMF, HR was not associated with Vp. LV volume was not related to Vp under low compliance, but inversely related to Vp under high compliance conditions (r = -0.56).

CONCLUSION

These in vitro findings may help elucidate the relationship of hemodynamic parameters to early diastolic LV filling.

Left ventricular diastolic function parameters in hypertensives

BACKGROUND

Hypertension is associated with left ventricular diastolic function abnormalities. There have been few studies evaluating left ventricular diastolic function in an African populace.

MATERIALS AND METHODS

Ninety-eight hypertensives (52 females, 46 males) and 99 normal controls (49 females, 50 males) were recruited for echocardiography. M-mode measurements and Doppler measurements of Mitral inflow and pulmonary venous flow were taken.

RESULTS

The hypertensives had significantly larger left ventricular wall thicknesses than the controls PWT: 0.93 (0.214) vs. 0.88 (0.130), p=0.039: septum: 0.93 (0.255) vs. 0.87 (0.131), p=0.039. The left ventricular mass indexed to the allometric power of height was larger in the hypertensives than in the controls. The Doppler parameters of peak A-wave velocity, E/A ratio, deceleration time, peak pulmonary venous S-wave, peak pulmonary venous D-wave, S/D ratio and peak pulmonary reverse flow velocity were significantly different between the hypertensives and the controls. The major determinant of left ventricular diastolic function parameters were age and the duration of hypertension. The level of the systolic blood pressure, left atrial size and ejection fraction are less important determinants.

CONCLUSION

Nigerian hypertensives have significantly different diastolic function indices when compared with normal controls.

Effects of halothane, sevoflurane and propofol on left ventricular diastolic function in humans during spontaneous and mechanical ventilation

BACKGROUND

There is limited knowledge of the effects of anaesthetics on left ventricular (LV) diastolic function in humans. Our aim was to evaluate these effects in humans free from cardiovascular disease.

METHODS

Sixty patients (aged 18-47 yr) who had no history or signs of cardiovascular disease were randomized to receive general anaesthesia with halothane, sevoflurane or propofol. Echocardiography was performed at baseline and during spontaneous respiration at 1 minimum alveolar concentration (MAC) of the inhalational agents or propofol 4 microg ml(-1) (step 1), and repeated during positive-pressure ventilation with 1 and 1.5 MAC of the inhalational agents or with propofol 4 and 6 microg ml(-1) (steps 2a and 2b). Analysis of echocardiographic measurements focused on heart rate corrected isovolumic relaxation time (IVRT(c)) and early diastolic peak velocity of the lateral mitral annulus (E(a)).

RESULTS

IVRT(c) decreased from baseline to step 1 in the halothane group (82 [95% CI, 76-88] ms and 74 [95% CI, 68-80] ms respectively; P=0.02), remained stable in the sevoflurane group (78 [95% CI, 72-83] ms and 73 [95% CI, 67-81] ms; n.s.) and increased in the propofol group (80 [95% CI, 74-86] ms and 92 [95% CI, 84-102] ms; P=0.02). E(a) decreased in the propofol group only (18.8 [95% CI, 16.5-19.9] cm s(-1) and 16.0 [95% CI, 14.9-17.9] cm s(-1); P=0.003). From step 2a to step 2b, IVRT(c) increased further in the propofol group (109 [95% CI, 99-121] ms and 119 [95% CI, 99-135] ms; P=0.04) but remained stable in the other two groups. E(a) did not change from step 2a to step 2b.

CONCLUSIONS

Halothane and sevoflurane did not impair LV relaxation, whereas propofol caused a mild impairment. However, the impairment by propofol was of a magnitude that is unlikely to cause clinical diastolic dysfunction.

The diagnostic value of Doppler echocardiographic indexes of diastolic filling for detecting demand ischemia in anesthetized patients

In awake patients, Doppler indexes of transmitral flow velocities have been shown to be more sensitive for detection of myocardial ischemia than echocardiographic evaluation of systolic wall-motion. The diagnostic value of these indexes in anesthetized patients is unknown. It might differ from that in awake patients because anesthetics and sympathomimetic drugs, which are commonly used in surgical patients with coronary artery disease (CAD), independently affect transmitral flow velocities.

METHODS

Several previously published transmitral Doppler echocardiographic indicators of ischemia (marked decreases in the ratio of peak early [E] to peak atrial [A] filling velocity [E/A], in the ratio of early to atrial time-velocity integral [E(I)/A(I)], in E, in E acceleration, and in total diastolic time-velocity integral) were compared with standard wall-motion analysis and ST-segment analysis during dobutamine stress echocardiography (DSE) in 17 anesthetized patients with CAD and 7 age-matched control patients at low risk of CAD.

RESULTS

All patients with CAD but no control patients showed new systolic wall-motion abnormalities and/or ST-segment changes. Decreases of >10% in E/A and E(I)/A(I) were found in 88% and 71% of the patients with CAD and in 71% and 100% of the control patients, respectively. These decreases were found during dobutamine infusion at as low as 10 mcg/kg/min in several control patients. None of the other studied Doppler indexes were found useful to detect ischemia.

CONCLUSIONS

Doppler echocardiography of diastolic transmitral flow velocities is of no appreciable diagnostic value for detecting ischemia in anesthetized patients who receive dobutamine at 10-40 mcg/kg/min.

825T allele of the G-protein beta3 subunit gene (GNB3) is associated with impaired left ventricular diastolic filling in essential hypertension

OBJECTIVE

Recently, a novel C825T polymorphism in the gene (GNB3) encoding for the G-protein beta3 subunit was identified. The 825T allele is associated with the generation of a novel splice variant, enhanced intracellular signal transduction, and arterial hypertension. In this study, we investigated the impact of the 825T allele on left ventricular structure and function in mild to moderate essential hypertensive subjects.

METHODS

In 34 white patients with established mild to moderate essential hypertension (World Health Organization stage I or II, mean age 52 +/- 9 years) genotype analysis of GNB3 C825T polymorphism, insertion/deletion polymorphism of the ACE gene and 1166 A/C polymorphism of the AT1 receptor gene was performed. In each patient, 24 h ambulatory blood pressure measurement (SpaceLabs 90207) and two-dimensional guided M-mode echocardiography combined with Doppler sonography were performed.

RESULTS

In our homogenous study group, the GNB3 825T allele was not associated with casual and 24 h ambulatory blood pressure (CC versus

TC/TT

144 +/- 13/92 +/- 8 versus 151 +/- 14/97 +/- 7 and 143 +/- 11/92 +/- 7 versus 150 +/- 16/ 96 +/- 9 mmHg, respectively) or parameters of left ventricular structure (relative wall thickness: CC versus TC/TT, 0.48 +/- 0.1 versus 0.46 +/- 0.1; left ventricular mass: CC versus TC/TT, 281 +/- 65 versus 299 +/- 80 g). However, transmitral flow variables reflecting left ventricular diastolic filling were impaired in patients expressing the TC/TT genotype (ratio of peak late (A) to early (E) velocities: CC versus TC/TT, 0.95 +/- 0.24 versus 1.2 +/- 0.26, P< 0.02; velocity time integrals A/E: CC versus TC/TT, 0.57 +/- 0.16 versus 0.76 +/- 0.23, P< 0.01) while all co-variables such as age, body mass index, ambulatory blood pressure, heart rate and end-diastolic volume were similar between the two groups. If patients were stratified according to the I/D polymorphism of the ACE gene and the A1166C polymorphism of the AT1 receptor gene, no differences in blood pressure, left ventricular structure or systolic and diastolic function of the left ventricle were found between different genotypes.

CONCLUSION

The GNB3 825T allele was associated with impaired left ventricular diastolic filling in hypertensive subjects in this study. Since alterations in left ventricular filling have been identified as an early marker of hypertensive heart disease, the GNB3 C825T polymorphism may influence cardiac adaptation to increased afterload.

Cardiovascular function before and after iron therapy by echocardiography in patients with iron deficiency anemia

BACKGROUND

The aim of the study was to estimate the left ventricular contractility using the ratio of left ventricular end-systolic wall stress to left ventricular end-systolic volume index in patients with iron deficiency anemia, for which there are no previous reports.

METHODS

Cardiovascular functions were evaluated using echocardiography and pulsed Doppler echocardiography in 30 children aged 3-14 years (hemoglobin 4.9-8.5 g/dL), before, during and after iron therapy. We also studied 38 healthy children as a control group.

RESULTS

The left ventricular preload was significantly higher and the left ventricular afterload was lower in the patients with anemia before iron therapy. The ratio of left ventricular end-systolic wall stress to left ventricular volume, an index of systolic function that is independent of preload and afterload, was significantly lower in the patients with anemia before iron therapy (before iron therapy 2.13 +/- 0.44, after therapy 3.52 +/- 0.76, healthy controls 3.42 +/- 0.70). Left ventricular early diastolic filling was significantly higher in the patients with anemia before iron therapy. The cardiac index was also significantly higher before therapy because of the increases in preload, heart rate and early diastolic filling, as well as the decrease of afterload. There were no significant differences in the indices of cardiovascular function between anemic patients after iron therapy compared with control subjects.

CONCLUSIONS

The ratio of left ventricular end-systolic wall stress to the left ventricular volume index and the cardiac index suggested that a hemoglobin concentration < or = 6 g/dL was associated with left ventricular dysfunction and circulatory congestion.

Left ventricular diastolic function in infants, children, and adolescents. Reference values and analysis of morphologic and physiologic determinants of echocardiographic Doppler flow signals during growth and maturation

OBJECTIVES

The aim of this study was to set up reference values for Doppler flow-derived left ventricular filling parameters and to evaluate physiologic determinants of changes in signal expression related to maturation.

BACKGROUND

In left ventricular diastolic function studies, age-related modulations in signal expression are observed. Assuming degenerative myocardial changes to be absent during childhood and adolescence, the determinants of these modulations must be different from those suspected in adults.

METHODS

Pulsed wave Doppler signals from the mitral valve tip region were recorded in 329 healthy subjects aged 2 months to 39 years. Multiple linear regression was used to evaluate statistical relations between Doppler flow signals and stroke volume in the mitral valve area.

RESULTS

Increasing early filling time velocity integral throughout maturation caused a decrease in atrial filling fraction from 0.34+/-0.06 to 0.24+/-0.04 (p < 0.005). Peak flow velocities during atrial systole decreased from infancy to adolescence (66+/-15 to 41+/-10 cm/s). Main effects on signal modulation were caused by heart rate, stroke volume and mitral ring area with a linear model fit (R2) of 0.79 for early filling phase (E)-time velocity integral, 0.6 for atrial filling phase peak velocity 0.84 for total E duration and 0.73 for E deceleration time. Atrial filling phase-time velocity integral, albeit significantly dependent on heart rate, was stable throughout growth.

CONCLUSIONS

During infancy and childhood, the stroke volume crossing the mitral valve is a main modulator for early filling phase (E)-time velocity integral and diastolic time intervals during early filling, whereas atrial filling phase parameters are mainly dependent on heart rate. This results in a more pronounced atrial filling during infancy and childhood.

Influence of Pulsed-Doppler Sample Volume Location and Upper Body Tilt on Left Ventricular Filling Indices in Healthy Persons

Doppler echocardiographic analysis of mitral flow is a noninvasive tool for analyzing left ventricular diastolic function. Changes in preload alter both normal and abnormal Doppler patterns of left ventricular filling. The velocities of mitral flow measured by transthoracic pulsed-Doppler echocardiography are different when measured at the mitral leaflet tips and at the mitral annulus. Transesophageal echocardiography provides an excellent image of cardiac anatomy whereby it is possible to place the Doppler sample volume exactly at the mitral annulus or at the tips of mitral leaflets. We studied with the use of transesophageal echocardiography how changes in preload and measurement at the annulus or valve tips affect the velocities of mitral flow. Upper body-up tilting (60 degrees ) decreased maximum E wave velocity by 16% and, hence, E/A ratio by 15%. A wave did not change by tilt. E wave velocity was 13%-15% lower at the annulus than at the tips of the mitral valve in both the supine and tilt position. E/A ratio was significantly higher at the tips than at the annulus of the mitral valve (supine, P = 0.048; tilt, P = 0.001). E/A ratio was 38% lower if the measurements were done at the annulus in the tilt position than at the tips with the patient lying horizontal. It may be important for pulsed-Doppler mitral flow-velocity measurements to be standardized for sample volume location and for body position.

Changes in Systolic and Diastolic Function Indexes Throughout Dobutamine Stress Echocardiography in Healthy Volunteers and Patients with Ischemic Heart Disease

BACKGROUND AND HYPOTHESIS: Dobutamine stress echocardiography is a well-established diagnostic method for investigating patients with suspected ischemic coronary disease. A positive test result is based on systolic parameters, but left ventricular filling parameters also are affected by myocardial ischemia. The aim of the present study was to study changes in both systolic and diastolic left ventricular variables throughout the test, including the period following it. METHODS AND RESULTS: Seven healthy control subjects (group I), 10 patients with chest pain but without significant coronary stenosis (group II), and 17 patients with significant coronary stenosis (group III) were entered in the study. Dobutamine stress echocardiography was performed according to a preset standardized protocol. Two-dimensional echocardiography and transmitral pulsed-Doppler images were stored for later analysis at rest, low dose, peak dose, and 5 minutes after termination of the dobutamine infusion. The wall motion score index increased from rest to low dose by 6.7% +/- 6.4% (P < 0.05) and to the peak dose by 39.1% +/- 9.9% (P < 0.001) in all three groups. The increase from rest to peak dose was significantly higher in groups I and II than in group III (P < 0.01). There was a significant increase in the atrial velocity-time integral (A-VTI) at peak dose in groups I and II (64.8% +/- 52.1% and 103.8% +/- 68.7%, respectively; P < 0.05 and <0.001), but no change in group III was noted. At the peak dose, A-VTI was significantly greater in groups I and II than in group III (P < 0.05). Among the 17 patients with proved coronary stenosis, 15 (88.2%) had a positive systolic response and 14 (82.3%) had a positive diastolic response, expressed as an A-VTI increase of </=2.5 cm. Among patients without significant stenosis, 9 (52.9%) had a negative systolic response, and 12 (70.6%) had a negative diastolic response. CONCLUSION: Changes in systolic parameters are the most sensitive ones to identify in a patient with significant coronary stenosis, but diastolic changes indicated by changes in A-VTI from rest to peak dose might contribute to decreasing the number of false-positive dobutamine stress echocardiography tests.

Functional and metabolic evaluation of the athlete's heart by magnetic resonance imaging and dobutamine stress magnetic resonance spectroscopy

BACKGROUND

The question of whether training-induced left ventricular hypertrophy in athletes is a physiological rather than a pathophysiological phenomenon remains unresolved. The purpose of the present study was to detect any abnormalities in cardiac function in hypertrophic hearts of elite cyclists and to examine the response of myocardial high-energy phosphate metabolism to high workloads induced by atropine-dobutamine stress.

METHODS AND RESULTS

We studied 21 elite cyclists and 12 healthy control subjects. Left ventricular mass, volume, and function were determined by cine MRI. Myocardial high-energy phosphates were examined by 31P magnetic resonance spectroscopy. There were no significant differences between cyclists and control subjects for left ventricular ejection fraction (59+/-5% versus 61+/-4%), left ventricular cardiac index (3.4+/-0.4 versus 3.4+/-0.4 L x min(-1) x m[-2]), peak early filling rate (562+/-93 versus 535+/-81 mL/s), peak atrial filling rate (315+/-93 versus 333+/-65 mL/s), ratio of early and atrial filling volumes (3.0+/-1.0 versus 2.6+/-0.6), mean acceleration gradient of early filling (5.2+/-1.4 versus 5.8+/-1.9 L/s2), mean deceleration gradient of early filling(-3.1 +/- 0.9 versus -3.2 +/- 0.7 L/s2), mean acceleration gradient of atrial filling (3.6+/-1.8 versus 4.5+/-1.7 L/s2), and atrial filling fraction (0.23+/-0.06 versus 0.26+/-0.04, respectively). Cyclists and control subjects showed similar decreases in the ratio of myocardial phosphocreatine to ATP measured with 31P magnetic resonance spectroscopy during atropine-dobutamine stress (1.41+/-0.20 versus 1.41+/-0.18 at rest to 1.21+/-0.20 versus 1.16+/-0.13 during stress, both P=NS).

CONCLUSIONS

Left ventricular hypertrophy in cyclists is not associated with significant abnormalities of cardiac function or metabolism as assessed by MRI and spectroscopy. These observations suggest that training-induced left ventricular hypertrophy in cyclists is predominantly a physiological phenomenon.

Echocardiographic evaluation of cardiac function in paediatric oncology patients treated with or without anthracycline

Using Doppler echocardiography, we studied the left ventricular systolic and diastolic function in 124 healthy control children (group C), 110 oncology patients who had received anthracycline (group A), and 76 oncology patients who had received chemotherapy not including anthracycline (group N), at rest and after supine bicycle exercise. The mean dosage of anthracycline that group A patients received was 219 +/- 95 mg/m2. Impaired systolic function was detected in 29% of the patients in group A and 4% in group N. Figures for impaired diastolic function for group A and N were 27% and 28% respectively. Abnormal diastolic function was detected more frequently in the first two years after chemotherapy in both groups. Four parameters measured at rest appeared to be specifically abnormal in group A but not in group N. These were ejection fraction, fractional shortening, rate-corrected velocity of circumferential fiber shortening (VCFC) and left ventricle peak systolic wall stress (LVWS). After exercise more parameters were abnormal in group N patients when compared to normal children, but abnormalities of VCFC and LVWS remained specific for group A. In conclusion, abnormalities of diastolic function were common among paediatric oncology patients no matter whether they had received anthracycline treatment or not. Abnormalities of systolic function were more specific to anthracycline toxicity. VCFC and LVWS were the most sensitive measurements for differentiating group N patients from group A patients.

Optimal number of beats for the Doppler measurement of cardiac output in atrial fibrillation

This study was undertaken to determine the optimum number of Doppler velocity waveforms required to calculate cardiac output in atrial fibrillation with the same degree of accuracy as that for sinus rhythm. Twenty-one patients in atrial fibrillation underwent calculations of cardiac output derived from aortic Doppler waveform velocity time integrals and RR intervals. The variability in estimates of the cardiac output was calculated with the successive addition of sequential beats and compared with that determined in a control group of 12 subjects in sinus rhythm. For the group in atrial fibrillation, a mean of 13 beats (range 4 to 17 beats) was required to achieve an estimation of cardiac output with a variability of less than 2%, compared with a mean of four beats in sinus rhythm. In atrial fibrillation, the mean number of beats required to determine cardiac output was approximately three times that necessary in sinus rhythm.

Quantitative assessment of diastolic filling function: a new Doppler echocardiographic method and in vitro validation

The effects of changes in preload and chamber compliance on the transmitral flow pattern was investigated with a fluid dynamics model. A decrease in compliance led to a steepening of the deceleration slope and a shortening of the pressure half-time in both restricted and nonrestricted valves. An increase in the preload led to a longer pressure half-time but did not affect the slope in the restricted valve. However, increased preload led to a shorter pressure half-time and a steeper slope in the nonrestricted valve. A mathematically derived method to measure the net atrioventricular compliance (-[annular area] va/[pvt [flow deceleration rate]]), where va and vt are flow velocities at the mitral anulus and the mitral tip levels) was then proposed. The values obtained by this method showed a strong correlation with true values (r2 = 0.89). A possibility of noninvasive quantitative assessment of diastolic filling function was implied.

Early effects of coronary artery bypass surgery and cold cardioplegic ischemia on left ventricular diastolic function: evaluation by computer-assisted transesophageal echocardiography

OBJECTIVE

Although left ventricular (LV) systolic function undergoes a temporary decrease after cardiopulmonary bypass (CPB) in patients undergoing coronary artery bypass grafting (CABG), data on the effects of CABG and cardioplegic arrest on LV diastolic function are contradictory. The objective of the present study was to further evaluate the effects of CABG and CPB on LV diastolic function.

DESIGN

A prospective study.

SETTING

A multi-institutional investigation at a university hospital.

PARTICIPANTS

20 patients on beta-receptor antagonists, scheduled for CABG and with a preoperative ejection fraction over 0.5.

INTERVENTIONS

Central hemodynamic measurements, transesophageal LV short-axis images, and mitral Doppler flow profiles were obtained before and after volume loading that in turn was performed both before surgical incision and after weaning from CPB.

MEASUREMENTS AND MAIN RESULTS

Heart rate, cardiac output, and peak atrial filling velocity increased; systemic vascular resistance decreased; whereas stroke volume, LV area ejection fraction, deceleration rate and slope of early diastolic filling, time-velocity integral of early diastolic filling, and the ratio between early and atrial peak filling velocity were unchanged post-CPB compared with pre-CPB. LV end-diastolic stiffness that was calculated for each patient pre-CPB and post-CPB using the formula: P = B*eS*A), where P is the LV filling pressure and A is the end-diastolic short-axis area, was unchanged post-CPB compared with pre-CPB.

CONCLUSIONS

Both the active and passive components of LV diastolic function are well maintained shortly after CABG and cardioplegic arrest in patients with a good preoperative systolic LV function.

Normal changes in left ventricular filling and hemodynamics during dobutamine stress echocardiography

During high-dose dobutamine infusion, there is a dose-dependent increase in cardiac output, a reduction in systemic vascular resistance, a reduction in left ventricular size, an increase in the mitral A wave velocity, a reduction in the E/A velocity ratio, and a reduction in the isovolumic relaxation time, with little change in the rate-corrected isovolumic relaxation time. Left ventricular cavity obliteration is common. This information may be useful in defining the mechanism of hypotension commonly seen during dobutamine stress echocardiography. It is speculated that the diastolic behavior of the left ventricle during dobutamine stress echocardiography, especially the isovolumic relaxation time, may provide an additional indicator of early myocardial ischemia, but this needs to be confirmed by larger independent studies.

Left ventricular diastolic function in children measured by Doppler echocardiography: normal values and relation with growth

OBJECTIVES

To determine normal values for variables of left ventricular diastolic function in children measured by Doppler echocardiography and their relations to body surface area (BSA).

BACKGROUND

There is increasing interest in echocardiographic assessment of left ventricular diastolic function in children but normal data for children are limited.

METHODS

Assessment of left ventricular diastolic function was performed in 130 normal participants (aged from 2.4 months to 19.6 years) from their transmitral flow patterns obtained by pulsed wave Doppler echocardiography.

RESULTS

Centile charts for commonly used left ventricular diastolic functional variables plotted against BSA are presented. Peak early diastolic filling velocity and atrial phase filling velocity integral were independent of BSA. Although most other filling indices showed strong relations with BSA, some had more curvilinear relations with BSA due to additional interactions with heart rate. The increase in left ventricular filling with growth is largely achieved by an increase in the early "passive" contribution to filling. The slower heart rates of older children are associated with lower atrial phase filling velocities but increased filling time, so the atrial contribution to filling remains relatively constant.

CONCLUSIONS

Normal values of many left ventricular diastolic function variables change with growth in children and cannot be extrapolated from adult data. The data presented are suitable for use in size matched matched comparative studies of left ventricular function in children. Careful standardisation of echocardiographic protocols is necessary to ensure the validity of any comparisons.

Left ventricular diastolic function after anthracycline chemotherapy in childhood: relation with systolic function, symptoms, and pathophysiology

OBJECTIVES

To examine left ventricular (LV) diastolic function in patients previously treated with anthracycline drugs for childhood malignancy. To consider clinical relevance, relations with systolic dysfunction, and the pathophysiology of anthracycline cardiotoxicity.

DESIGN

Cross sectional echocardiographic study of LV function.

SETTING

Supraregional centre for paediatric cardiology, principal centre for the treatment of childhood malignancy in southwest England.

PATIENTS

226 of 236 patients surviving between 6.5 months and 17 (median 5.3) years from initial anthracycline treatment for childhood malignancy attended for clinical and echocardiographic examination. Cumulative anthracycline doses were between 50 and 750 (median 300) mg/m2. 22 patients had also received cardiac irradiation.

METHODS

Detailed assessment of transmitral diastolic pulsed wave Doppler flow patterns along with LV dimensions and systolic function measured by M mode echocardiography.

MAIN OUTCOME MEASURES

Peak early (E) and atrial (A) phase filling velocities and EA ratio, time and acceleration and deceleration to and from peak E velocity, velocity integrals and ratio, isovolumic relaxation time (IVRT), and heart rate were measured. Results were examined in relation to LV cavity and posterior wall dimensions and shortening fraction (SF), and compared with paired control data matched for body surface area.

RESULTS

Eleven (5%) patients had abnormal effort tolerance. Fifty one (23%) had SF < 30% and SF was inversely correlated with cumulative dose and time from treatment. The relative risk of symptomatic cardiac failure was greatly increased by prior irradiation; > 60% of irradiated patients who received > 400 mg/m2 of anthracycline were symptomatic. Early diastolic filling was relatively normal or enhanced at low anthracycline doses or when SF was preserved, with a shorter IVRT and increased atrial phase filling. Early filling was reduced at higher doses or with reduced SF, with longer IVRT and a further increase in atrial phase filling. A more "restrictive" pattern of diastolic filling (with high E and low A velocities) was seen in some patients, particularly after cardiac irradiation.

CONCLUSIONS

Significant abnormalities of diastolic function are associated with anthracycline induced cardiac damage. These are not linearly related to anthracycline dose but appear to reflect the underlying myocardial pathophysiology associated with anthracycline toxicity, which is not demonstrated by the standard M mode echocardiogram. Although the overall clinical significance of such diastolic dysfunction is uncertain, some individual abnormalities may have significant management and therapeutic implications.

Evaluation of Doppler echocardiographic atrial pacing stress test in the detection of coronary artery disease

Doppler echocardiographic atrial pacing stress tests were performed in 23 patients with coronary artery disease (CAD) and 35 normal subjects. It was found that the peak flow velocity (PFV) through the mitral valve decreased at 160 beats per minute (BPM) during pacing in the CAD group (P less than 0.01), but no significant variation was seen in the normal group. No differences between the two groups were observed in 1/3 filling fraction (1/3 FF), total diastolic filling period (DFP) and the ratio of early diastolic filling period (EDFP) to DFP before pacing. However, 1/3 FF and DFP decreased and EDFP/DFP increased immediately following rapid pacing in the CAD group but did not change in the normal group (P less than 0.05, 0.01, and 0.001 respectively). The peak flow velocity during atrial contraction (APFV), time velocity integral during atrial contraction (ATVI) and the ratio of ATVI to total TVI (ATVI/TTVI) increased immediately following pacing in the CAD group. Using two of three indices--ATVI/TTVI more than 0.35, ATVI increase and 1/3 FF decrease immediately following pacing--as diagnostic criteria for CAD, the sensitivity was 86% and the specificity was 77%. It may be concluded that the Doppler echocardiographic atrial pacing stress test is a feasible and reliable method for detecting CAD.