Modulation of left atrial function by ventricular filling impairment

Predictors of Progression of Tricuspid Regurgitation in Patients with Persistent Atrial Fibrillation

Previous studies have shown that tricuspid regurgitation (TR) can be developed in patients with atrial fibrillation (AF) due to annular dilatation. This study aimed to investigate the incidence and predictors of the progression of TR in patients with persistent AF. A total of 397 patients (66.9±11.4 years, 247 men; 62.2%) with persistent AF were enrolled between 2006 and 2016 in a tertiary hospital, and 287 eligible patients with follow-up echocardiography were analyzed. They were divided into two groups according to TR progression (progression group [n=68, 70.1±10.7 years, 48.5% men] vs. non-progression group [n=219, 66.0±11.3 years, 64.8% men]). Among 287 patients in the analysis, 68 had worsening TR severity (23.7%). Patients in the TR progression group were older and more likely to be female. Patients with left ventricular ejection fraction <50% were less frequent in the progression group than those in the non-progression group (7.4% vs. 19.6%, p=0.018). Patients with mitral valve disease were more frequent in the progression group. Multivariate analysis with COX regression demonstrated independent predictors of TR progression, including left atrial (LA) diameter >54 mm (HR 4.85, 95%CI 2.23-10.57, p<0.001), E/e' (HR 1.05, 95%CI 1.01-1.10, p=0.027), and no use of antiarrhythmic agents (HR 2.20, 95%CI 1.03-4.72, p=0.041). In patients with persistent AF, worsening TR was not uncommon. The independent predictors of TR progression turned out to be greater LA diameter, higher E/e', and no use of antiarrhythmic agents.

Negative Inotropic Effect of BGP-15 on the Human Right Atrial Myocardium

Cardiovascular morbidity and mortality carry great socioeconomic burden worldwide that mandates the development of new, efficacious therapeutic agents with limited adverse effects. O-(3-piperidino-2-hydroxy-1-propyl) nicotinic acid amidoxime (BGP-15) is a known, well-tolerable drug candidate that exerts beneficial effects in several disease models. As BGP-15 has a significant structural similarity with propranolol, it arose that BGP-15 might also have a direct effect on the heart. Thus, in the present work, we investigated the effect of BGP-15 and propranolol on the contractility of isolated, paced, human right atrial samples (obtained from patients undergone open-heart surgery), with or without previous isoproterenol (ISO) stimulation (evoking an indirect or direct effect, respectively). We found that both BGP-15 and propranolol exerted direct as well as indirect negative inotropic effects on the atrial myocardium, reaching similar maximal response. However, BGP-15 had considerably smaller potency than propranolol regarding both types of negative inotropy. In addition, BGP-15, in contrast to propranolol, had a significantly greater indirect negative inotropic effect on samples exhibiting strong response to ISO. Moreover, the indirect negative inotropic effect of BGP-15 was significantly greater on samples derived from diabetic patients than on samples obtained from non-diabetic ones. Our results suggest that the enhanced ISO sensitivity is associated with the diabetic state, and BGP-15 exerts greater negative inotropic effect on the human atrial myocardium in both conditions (as compared to the atrial tissue that is not ISO oversensitive and/or diabetic). Additionally, the negative inotropic effects of BGP-15 and propranolol seem to be mediated by in part different molecular pathways in the atrial myocardium.

Changes in ductus venosus flow profile in twin-twin transfusion syndrome: role in risk stratification

OBJECTIVES

To evaluate changes in ductus venosus (DV) waveforms and the timing of these changes in twin-twin transfusion syndrome (TTTS), to relate these to disease severity and to assess the clinical applicability of the suggested measurements in the prediction of TTTS.

METHODS

DV time intervals and velocity-time integrals (VTI) normalized to cardiac cycle and total VTI, respectively, as well as velocity ratios were analyzed in 149 monochorionic diamniotic (MCDA) twin pairs. Pregnancies were assigned to the following groups: uncomplicated MCDA (n = 29); TTTS Stages I+II (n = 50); TTTS Stages III+IV (n = 49); and pre-TTTS (n = 21), of which 14 remained stable and seven progressed to TTTS. Intertwin differences were calculated as larger/recipient minus smaller/donor and related to disease severity. Receiver-operating characteristics curve analysis was used to distinguish TTTS vs uncomplicated MCDA and pre-TTTS progressing to TTTS vs non-progressing pre-TTTS. Intra- and interobserver reliability of measurement of DV parameters were evaluated using intraclass correlation coefficients (ICCs).

RESULTS

No intertwin differences in DV parameters were found in uncomplicated MCDA pregnancies. Diastolic VTIs and filling times were significantly shorter in recipient twins in TTTS cases and in larger pre-TTTS twins in comparison with their cotwins. Time intervals, VTIs and velocity ratios correlated significantly with Quintero stages. An intertwin difference in early filling time (eT) normalized to cardiac cycle, eT (%) ≤ -3.6%, could differentiate TTTS from uncomplicated MCDA pregnancies (82.8% sensitivity; 79.8% specificity) and eT (%) ≤ -2.8% predicted progression to TTTS (73.1% sensitivity; 67.4% specificity).

CONCLUSIONS

DV flow profiles and timing of waveform events are already altered in pre-TTTS and early-stage disease, reflecting abnormal ventricular filling and circulatory imbalance. Intertwin comparison of filling times and VTI may allow prediction of evolving TTTS in MCDA pregnancies. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Atrial conduction time, and left atrial mechanical and electromechanical functions in patients with polycystic ovary syndrome: interatrial conduction delay

Background

Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders of women during the reproductive period. Cardiovascular risk factors are more frequent in patients with PCOS. We aimed to investigate the P-wave dispersion (Pd), inter- and intra-atrial conduction time and mechanical functions of the left atrium (LA) in patients with PCOS.

Methods

Forty-eight patients with PCOS and 38 normal healthy women were enrolled in this study. A 12-lead surface electrocardiogram was used to evaluate Pd. Left ventricular (LV) functions were measured using conventional and tissue Doppler imaging (TDI) methods. Inter- and intra-atrial conduction times were measured by TDI. LA volumes were measured echocardiographically with the biplane area–length method from the apical four-chamber view.

Results

Heart rate (82.02 ± 13.15 vs 74.24 ± 11.02 bpm, p = 0.014) and Pd were significantly increased in the PCOS patients [27 ± 5 vs 24 ± 6 ms, p = 0.035]. Transmitral E/A ratio was significantly lower in the PCOS patients than in the controls (1.5 ± 0.3 vs 1.7 ± 0.4 m/s, p = 0.023). Passive emptying volume (12.54 ± 4.39 vs 15.28 ± 3.85 ml/m², p = 0.004) and passive emptying fraction [54.4 (21–69) vs 59.1% (28–74), p = 0.008] were significantly decreased in PCOS patients. Total emptying volume was significantly decreased (17.9 ± 5.49 vs 20.67 ± 4.29 ml/m2, p = 0.018) in PCOS patients. Interatrial (19 ± 7.4 vs 15 ± 6.4 ms, p = 0.035) and intra-atrial [8.5 (1–19) vs 5 ms (1–20), p = 0.026] electromechanical delays were found to be significantly higher in PCOS patients.

Conclusion

This study showed that patients with PCOS had increased inter- and intra-atrial conduction delays, and decreased LA passive emptying volumes and fractions.

Left Atrial Function in Patients with Chronic Chagasic Cardiomyopathy

BACKGROUND

Chagas disease is a cause of dilated cardiomyopathy, and information about left atrial (LA) function in this disease still lacks.

OBJECTIVE

To assess the different LA functions (reservoir, conduit and pump functions) and their correlation with the echocardiographic parameters of left ventricular (LV) systolic and diastolic functions.

METHODS

10 control subjects (CG), and patients with Chagas disease as follows: 26 with the indeterminate form (GI); 30 with ECG alterations (GII); and 19 with LV dysfunction (GIII). All patients underwent M-mode and two-dimensional echocardiography, pulsed-wave Doppler and tissue Doppler imaging.

RESULTS

Reservoir function (Total Emptying Fraction: TEF): (p <0.0001), lower in GIII as compared to CG (p = 0.003), GI (p <0.001) and GII (p <0.001). Conduit function (Passive Emptying Fraction: PEF): (p = 0.004), lower in GIII (GIII and CG, p = 0.06; GI and GII, p = 0.06; and GII and GIII, p = 0.07). Pump function (Active Emptying Fraction: AEF): (p = 0.0001), lower in GIII as compared to CG (p = 0.05), GI (p<0.0001) and GII (p = 0.002). There was a negative correlation of E/e' (average) with the reservoir and pump functions (TEF and AEF), and a positive correlation of e' (average) with s' wave (both septal and lateral walls) and the reservoir, conduit and pump LA functions.

CONCLUSION

An impairment of LA functions in Chagas cardiomyopathy was observed.

Left atrium function in patients with coronary artery disease

PURPOSE OF REVIEW

The left atrial cavity has recently been identified as a potential biomarker for cardiac and cerebrovascular accidents. This review examines the potential of left atrial size and function in predicting cardiovascular disease in the general population and outcomes in coronary artery disease (CAD) patients.

RECENT FINDINGS

The atrium is perfused primarily by branches of the proximal left circumflex coronary artery (LCx), and depression of the cavity mechanical performance has been demonstrated in experimental studies during LCx occlusion. Thus, left atrial volume and function assessment may have prognostic relevance, particularly in CAD patients. Such a line of thinking, however, is challenged by the widespread notion that the contribution by left atrial chamber morphology and functional quantitation to the risk stratification process after a first cardiovascular event is not adequately considered. However, a number of studies have shown that left atrial volume predicts survival and major adverse events after an acute myocardial infarction. Left atrial remodeling also provides an important overall prognostic information and correlates with brain natriuretic peptide after primary percutaneous coronary interventions.

SUMMARY

Evaluation of left atrial size and function is currently of great interest and it will be more so in the very near future, given its potential for insights into the pathophysiology of the ischemic heart, which makes it an important clinical risk identifier in CAD patients.

Left Atrial Longitudinal Speckle Tracking Echocardiography in Healthy Aging Heart

Background:

Left atrial volume (LAV) and function are connected to the left ventricular (LV) haemodynamic patterns. To define the changes of LAV and functions to counterbalance age-related LV diastolic impairment, this study was undertaken.

Methods:

2D-Left Atrial Speckle Tracking Echocardiography (2D-LASTE) was used to define both LAV and functions in an aged healthy population (group II) respect to adult healthy controls (group I).

Results:

Results showed an increasing of left atrial volume indices (LAVI) (maximum, minimum, pre-a) in old subjects in comparison with those obtained in adult healthy controls. On the contrary, LAVI passive emptying unchanged and LAVI passive fraction reduced with advanced age. Finally, LAVI active emptying increased with advancing age to compensate the age-dependent left ventricular diastolic dysfunction. The values of global systolic strain (S); systolic strain rate (SrS); early diastolic strain rate (SrE), and late diastolic strain rate (SrA) were also calculated. With reference to the function, our study confirmed that LA conduit function deteriorates with age while booster pump increases respect to adult controls and reservoir phase is maintained.

Conclusions:

The echocardiographic findings obtained with conventional and tissue Doppler confirmed the connection between LA functions and volumes and age-related LV dysfunction. Conclusively, 2D-LASTE appears to be a reliable tool to evaluate the role of LA to compensate the derangement of left ventricle happening with ageing.

Cardiac function after repair of tetralogy of fallot: how are the atria performing? pilot study by cardiac magnetic resonance imaging

The atria of the heart function as reservoir, conduit, and active pump and are critical for ventricular filling and cardiac output. We sought to evaluate right (RA) and left atrial (LA) function in patients after tetralogy of Fallot (TOF) repair by using cardiovascular magnetic resonance. Twelve TOF patients, age 16.7 ± 6.1 years, weight 50.9 ± 14.9 kg, were compared to 10 healthy volunteers, age 18.8 ± 6.8 years, weight 52.3 ± 20.8 kg. Both atria and both ventricles were imaged in short-axis planes by Steady State Free Precession. Volume changes and all derived atrial functional parameters were calculated from the volume/time curves obtained after segmentation on the cine images. Blood flow across the AV valves was used to define ventricular diastolic dysfunction. TOF patients showed similar maximal RA volume compared to controls, but increased volumes at mid-diastole (p < 0.05), resulting in a decreased cyclic volume change and atrial filling fraction (p < 0.01), and a decreased passive emptying volume and fraction (p < 0.01). In patients with diastolic dysfunction, conduit volume was increased (p < 0.05), and active emptying volume and fraction tended to be increased, respectively. No significant changes were found in LA, except for a decreased passive emptying fraction (p < 0.05). RA function and particularly reservoir function are impaired in TOF patients. The RA conduit/reservoir ratio is increased and reflects the lost of the ability of the atrium to fill the ventricle by pulsatile flow.

Metabolic syndrome is associated with atrial electrical and mechanical dysfunction

OBJECTIVE

In this study, we aimed to investigate the left atrial (LA) electrical and mechanical functions in patients with metabolic syndrome (MetS).

SUBJECTS AND METHODS

The study population consisted of 87 patients with MetS and 67 controls. Intra-atrial and interatrial electromechanical delays (EDs) were measured with tissue Doppler imaging. P-wave dispersion (Pd) was calculated from the 12-lead electrocardiograms. LA volumes were measured echocardiographically by the biplane area-length method.

RESULTS

Intra-atrial and interatrial EDs and Pd were significantly higher in patients with MetS (10.3 ± 6.3, 21.0 ± 11.5 and 41.7 ± 10.8) than in controls (7.4 ± 5.5, 12.3 ± 10.4 and 29.2 ± 7.4; p = 0.003, p < 0.001 and p < 0.001, respectively). The LA preatrial contraction volume and active emptying volumes were higher in this population, but the LA passive emptying fraction was lower. In the multivariate linear regression analysis, the presence of MetS, LA active emptying volume and left ventricular early diastolic (E) wave velocity/late diastolic (A) wave velocity (E/A) ratios were independent correlates of interatrial ED (p = 0.002, p = 0.001 and p = 0.025, respectively).

CONCLUSIONS

This study showed that intra-atrial and interatrial EDs and Pd were prolonged and LA mechanical functions were impaired in patients with MetS.

The relationship between atrial electromechanical delay and left atrial mechanical function in stroke patients

OBJECTIVE

The aim of this study was to evaluate the relationship between atrial electromechanical delay (EMD) measured with tissue Doppler imaging (TDI) and left atrial (LA) mechanical functions in patients with ischemic stroke and compare them with healthy controls.

METHODS

Thirty patients with ischemic stroke were enrolled into this cross-sectional, observational study. The control group consisted of 35 age- and gender-matched apparently healthy individuals patients. Acute cerebral infarcts of probable embolic origin were diagnosed via imaging and were confirmed by a neurologist. Echocardiographically, time intervals from the beginning of P wave to beginning of A wave from the lateral and septal mitral and right ventricular tricuspid annuli in TDI were recorded. The differences between these intervals gave the mechanical delays (inter- and intra-atrial). Left atrial (LA) volumes were measured using the biplane area-length method, and LA mechanical function parameters were calculated. Statistical analysis was performed using student's t-test, chi-squared test, and Pearson's test.

RESULTS

The laboratory and clinical characteristics were similar in the two groups. Increased left atrial EMD (21.36±10.38 ms versus 11.74±6.06 ms, p<0.001), right atrial EMD (13.66±8.62 ms versus 9.66±6.81 ms, p=0.040), and interatrial EMD (35.03±9.95 ms versus 21.40±8.47 ms, p<0.001) were observed in stroke patients as compared to controls. Active LA emptying volume and fraction and passive LA emptying volumes and fraction were similar between controls and stroke patients. Total LA emptying volumes were significantly increased in stroke patients as compared to healthy controls (33.19±11.99 mL/m2 versus 27.48±7.08 mL/m2, p=0.021).

CONCLUSION

According to the results of our study, interatrial electromechanical delay may be a new predictor for ischemic stroke.

Left atrial dysfunction detected by speckle tracking in patients with systemic sclerosis

BACKGROUND

Cardiac involvement is a relevant clinical finding in systemic sclerosis (SSc) and is associated with poor prognosis. Left atrial (LA) remodeling and/or dysfunction can be an early sign of diastolic dysfunction. Two-dimensional speckle tracking echocardiography (STE) is a novel and promising tool for detecting very early changes in LA myocardial performance.

AIM

To assess whether STE strain parameters may detect early alterations in LA function in SSc patients.

METHODS

Forty-two SSc patients (Group 1, age 50 ± 14 years, 95% females) without clinical evidence for cardiac involvement and 42 age- and gender-matched control subjects (Group 2, age 49 ± 13 years, 95% females) were evaluated with comprehensive 2D and Doppler echocardiography, including tissue Doppler imaging analysis. Positive peak left atrial longitudinal strain (ϵ pos peak), second positive left atrial longitudinal strain (sec ϵ pos peak), and negative left atrial longitudinal strain (ϵ neg peak) were measured using a 12-segment model for the LA, by commercially available semi-automated 2D speckle-tracking software (EchoPac PC version 108.1.4, GE Healthcare, Horten, Norway).

RESULTS

All SSc patients had a normal left ventricular ejection fraction (63.1 ± 4%). SSc patients did not differ from controls in E/A (Group 1 = 1.1 ± 0.4 vs Group 2 = 1.3 ± 0.4, p = .14) or pulmonary arterial systolic pressure (Group 1 = 24.1 ± 8 mmHg vs Group 2 = 21 ± 7 mmHg, p = .17). SSc patients did not show significantly different indexed LA volumes (Group 1 = 24.9 ± 5.3 ml/m2 vs Group 2 = 24.7 ± 4.4 ml/m2, p = .8), whereas E/e' ratio was significantly higher in SSc (Group 1 = 7.6 ± 2.4 vs Group 2 = 6.5 ± 1.7, p<0.05), although still within normal values. LA strain values were significantly different between the two groups (ϵ pos peak Group 1 = 31.3 ± 4.2% vs Group 2 = 35.0 ± 7.6%, p < .01, sec ϵ pos peak Group 1 = 18.4 ± 4 vs Group 2 = 21.4 ± 7.6, p < 0.05).

CONCLUSION

2D speckle-tracking echocardiography is a sensitive tool to assess impairment of LA mechanics, which is detectable in absence of changes in LA size and volume, and may represent an early sign of cardiac involvement in patients with SSc.

Paricalcitol and endothelial function in chronic kidney disease trial

Altered vitamin D metabolism and low levels of the active form of this vitamin, 1,25-dihydroxy-vitamin D, is a hallmark of chronic kidney disease (CKD), but there is still no randomized controlled trial testing the effect of active forms of vitamin D on vascular function in patients with CKD. Paricalcitol and ENdothelial fuNction in chronic kidneY disease (PENNY) is a double-blinded randomized controlled trial (ClinicalTrials.gov, NCT01680198) testing the effect of an active form of vitamin D, paricalcitol (2 μg/d×12 weeks) on endothelium-dependent and endothelium-independent vasodilatation in 88 patients with stage 3 to 4 CKD and parathormone >65 pg/mL (paricalcitol, n=44; placebo, n=44). Paricalcitol treatment reduced parathormone (-75 pg/mL; 95% confidence interval, -90 to -60), whereas parathormone showed a small rise during placebo (21 pg/mL; 95% confidence interval, 5-36). Blood pressure did not change in both study arms. Baseline flow-mediated dilation was identical in patients on paricalcitol (3.6±2.9%) and placebo (3.6±2.9%) groups. After 12 weeks of treatment, flow-mediated dilation rose in the paricalcitol but not in the placebo group, and the between-group difference in flow-mediated dilation changes (the primary end point, 1.8%; 95% confidence interval, 0.3-3.1%) was significant (P=0.016), and the mean proportional change in flow-mediated dilation was 61% higher in paricalcitol-treated patients than in placebo-treated patients. Such an effect was abolished 2 weeks after stopping the treatment. No effect of paricalcitol on endothelium-independent vasodilatation was registered. Paricalcitol improves endothelium-dependent vasodilatation in patients with stage 3 to 4 CKD. Findings in this study support the hypothesis that vitamin D may exert favorable effects on the cardiovascular system in patients with CKD.

Association of left atrial myocardial function with left ventricular diastolic dysfunction in subjects with preserved systolic function: a strain rate imaging study

BACKGROUND

The purpose of this study was to investigate the relationship between left atrial (LA) myocardial function and left ventricular (LV) diastolic dysfunction in subjects with preserved LV ejection fraction (LVEF).

METHODS

The study included a group of 118 hypertensive patients and normal subjects. LV diastolic dysfunction was classified into 4 groups: none, mild, moderate, and severe. Peak strain rates in systole (S-Sr), early diastole (E-Sr), and late diastole (A-Sr) were obtained from Doppler-derived strain rate imaging to evaluate LA myocardial deformation.

RESULTS

No significant difference in LA dimension was observed in subjects with different degrees of LV diastolic dysfunction, although LA myocardial strain rate parameters were all significantly different across the 4 groups (all with P < 0.001). Compared with patients of normal diastolic function, the mild diastolic dysfunction group had significantly lower E-Sr (0.62 ± 0.18 s⁻¹ vs 1.20 ± 0.38 s⁻¹, P < 0.001) and S-Sr (0.78 ± 0.16 s⁻¹ vs 0.94 ± 0.22 s⁻¹, P < 0.001) but increased A-Sr (1.14 ± 0.29 s⁻¹ vs 1.00 ± 0.23 s⁻¹, P = 0.05).

CONCLUSIONS

By using strain rate imaging, significant changes of LA deformation in response to different stages of LV diastolic dysfunction were detected in subjects with preserved LVEF. Quantification of LA myocardial function rather than LA size may have the potential to predict early LV diastolic dysfunction in subjects with preserved LVEF.

Assessment of left atrial function in diabetes mellitus by left atrial volume tracking method

The value of the left atrial volume tracking (LAVT) method in the evaluation of left atrial (LA) function in patients with diabetes mellitus (DM) was examined in this study. Fifty-eight DM patients as DM group and 40 healthy people as normal control group were enrolled in this study. EUB-6500 echocardiographic imaging system with LAVT was applied to display and analyze the LA volume curve imaging on LV apical two and four chamber views. The maximal LA volume at end-systole (LAV(max)), LA volume at the onset of ECG-P wave (LAV(p)), the minimal LA volume at end-diastole (LAV(min)) from the LA volume curve were acquired and recorded. All values above were standardized by body surface area (BSA). Then the passive, active and total LA volume (LAVIpass, LAVIact, LAVItotal) and empting rate (%LAVIpass, %LAVIact, %LAVItotal), effective passive and active empting rate (%eLAVIpass, %eLAVIact), and the proportionality of passive empting volume and active empting volume were calculated. The LAVIp, LAVIact, LAVItotal, %LAVIact, %LAVItotal and %eLAVIact were significantly higher in the DM group than those in the control group, whereas the LAVIpass, %LAVIpass, %eLAVIpass and LAVIpass/act were lower (all P<0.05). For the LA volume change in DM, the active empting volume was enhanced at end-diastole. It was concluded that LAVT is a potentially useful tool to evaluate the function of LA.

Two-dimensional speckle tracking echocardiography for the assessment of atrial function

Echocardiography is the most common diagnostic method for assessing atrial function but the technique has some limitations. Traditionally, assessment of left atrial function has been performed by measuring volumes with 2D echocardiography. Additionally, it can be assessed with transmitral Doppler and pulmonary vein Doppler. Recently, an alternative method has been incorporated, namely, measurement of myocardial deformation with color tissue Doppler-derived strain. However, this method has several limitations, such as suboptimal reproducibility, angle-dependence, signal artifacts and the fact that it only measures regional strain and does not obtain information about the curved portion of the atrial roof. To overcome these limitations in the quantification of atrial function, the use of speckle tracking echocardiography (STE) strain has been proposed. This technique is not derived from Doppler but rather from 2D echocardiography; it is angle-independent and allows one to measure global as well as regional atrial strain. In this editorial, we describe the physical and pathophysiological concepts of STE and underline the clinical usefulness of this new technique.

Methods and reliability of echocardiographic assessment of left atrial size and mechanical function in horses

OBJECTIVE

To assess the feasibility, describe the techniques, and determine the reliability of transthoracic echocardiography for characterization of left atrial (LA) size and LA mechanical function in horses.

ANIMALS

6 healthy adult horses.

PROCEDURES

Repeated echocardiographic examinations were performed independently by 2 observers in standing, unsedated horses by use of 2-dimensional echocardiography, pulsed-wave flow Doppler, and tissue Doppler imaging (TDI) techniques. Test reliability was determined by estimating measurement variability, within-day interobserver variability, and between-day inter- and intraobserver variability of all echocardiographic variables. Variability was expressed as the coefficient of variation (CV) and the absolute value below which the difference between 2 measurements will lie with 95% probability.

RESULTS

Most echocardiographic variables of LA size had low overall variability (CV, < 15%). Among the 2-dimensional indices of LA mechanical function, area-based and volume-based ejection phase indices had moderate between-day variability (CV usually < 25%). Transmitral Doppler flow indices were characterized by low to high between-day variability (CV, 6% to 35%). The TDI wall motion velocities had high between-day variability (CV, > 25%), whereas most TDI-derived time intervals had low variability (CV, < 15%).

CONCLUSIONS AND CLINICAL RELEVANCE

LA size and mechanical function can be reliably assessed in standing, unsedated horses by use of 2-dimensional echocardiography, transmitral blood flow velocity profiles, and analyses of LA wall motion by use of TDI. These results may provide useful recommendations for echocardiographic assessment of LA size and function in horses.

Left atrial stiffness and its implications for cardiac function

Proper atrial function is essential for overall cardiovascular performance, mainly by its four major functions, namely, bioelectrical, hormonal, metabolic and hemodynamic. With regard to the latter, atria modulate ventricular filling by smoothing the transformation of the continuous venous return to the intermittent filling pattern of the ventricles during diastole through three main components: a phase of reservoir mainly during ventricular systole, a conduit phase during ventricular diastole and an active phase in late ventricular diastole. Although the atria assume a dynamic role in ventricular filling progression, atrial function and emptying pattern is, conversely, highly influenced by the ventricular diastolic wall stress, underlying the close connection observed between these chambers. This review focuses essentially on left atrial mechanical role, particularly on the physiological and clinical consequences of disturbed atrial compliance.

Analysis of Atrial and Ventricular Performance by Tissue Doppler Imaging in Patients with Atrial Septal Defects before and after Surgical and Catheter Closure

OBJECTIVE

To compare the effects of surgical and device closure of atrial septal defects on atrial and ventricular performance assessed by the novel tissue Doppler derived strain rate.

BACKGROUND

Despite the increasing number of transcatheter closures, there is no information comparing the effect of the transcatheter closure technique on atrial performance with that of conventional surgery. Tissue Doppler derived strain rate can effectively quantify local myocardial function independent of the overall heart motion.

DESIGN AND PATIENTS

Twenty-four patients [aged 21.5 (6-70) years] with isolated atrial septal defect of the secondum type before and 1 week after surgical (n = 12) or Amplatzer Septal Occluder closure (n = 12) and 30 healthy controls [aged 26.0 (2-58) years] were studied. Atrial and ventricular strain rate curves were assessed in the middle of their corresponding lateral walls in an apical four-chamber view. The systolic, early diastolic, and late diastolic strain rates peaks were measured.

RESULTS

Compared to preclosure condition, the right atrial late diastolic (P < 0.01), right ventricular systolic (P < 0.01), right ventricular early diastolic (P < 0.01), and left atrial late diastolic peak (P < 0.01) strain rates were reduced after surgery but not after Amplatzer Septal Occluder closure. The LV parameters did not significantly differ before and after atrial septal defect closure by either technique.

CONCLUSIONS

In contrast to surgery, transcatheter closure of atrial septal defect preserves atrial and right ventricular function. Tissue Doppler derived strain rate can be applied to provide quantitative analysis of regional atrial and ventricular performance.

The effect of pulmonary hypertension on left atrial mechanical functions in chronic obstructive lung disease

BACKGROUND

Left atrial (LA) function is an important determinant of left ventricular (LV) filling. However, the effect of pulmonary hypertension (PH) on LA mechanical function in chronic obstructive lung disease (COLD) has not been studied, yet.

METHODS

49 patients with COLD and 25 controls were included in this study. Patients were divided into two subgroups: patients without PH (group 1, n=21) and with PH (group 2, n=28). LA volumes were determined at mitral valve opening (Vmax), at onset of atrial systole (Vp) and at mitral valve closure (Vmin) according to biplane area-length method. The following LA parameters were calculated: passive emptying volume (PEV=Vmax-Vp), conduit volume [CV=LV stroke volume-(Vmax-Vmin)], passive emptying fraction (PEF=PEV/Vmax), active emptying volume (AEV=Vp-Vmin), active emptying fraction (AEF=AEV/Vp), total emptying volume (TEV=Vmax-Vmin), percent contribution of PEV, CV and AEV to LV stroke volume.

RESULTS

Vmax (p<0.01), PEV (p<0.001) and TEV (p<0.05) were lower in group 2 than in the controls, and the differences between group 1 and control group were insignificant (p>0.05). Vp, Vmin, CV and AEV did not differ among three groups. Percent contribution to LV filling of the PEV was decreased in group 2 when compared to group 1 (p<0.05) and the controls (p<0.01). Percent contribution to LV filling of the AEV was increased in group 2 when compared to the controls (p<0.05). There were inverse correlations between pulmonary artery pressure and the following parameters: LV stroke volume (r=-0.43, p<0.01), mitral E/A (r=-54, p<0.001), Vmax (r=-0.35, p<0.05), PEV (r=-40, p<0.01) and PEF (r=-0.43, p<0.01).

CONCLUSION

This study shows that the alterations of LA mechanical functions in patients with COLD are closely correlated to PH levels. Furthermore, these results underline the importance of maintaining a sinus rhythm in these patients.

Quantitative analysis of right atrial performance after surgical repair of tetralogy of Fallot

We aimed to assess the right atrial performance in patients after surgical correction of tetralogy of Fallot, and to clarify the relationship between the pump function of the right atrium and right ventricular systolic function. We included in the study 50 asymptomatic patients following corrective surgery of tetralogy of Fallot, comparing them to 30 normal subjects. Right atrial areas were measured by echocardiography, and the active fractional area of emptying was expressed, in percentages, as the area measured at the onset of atrial contraction, minus the minimal area, divided by the area at the onset of atrial contraction. We used this value to assess the atrial pump function. Right atrial peak strain rates were measured by tissue Doppler imaging. Compared to controls, patients with tetralogy of Fallot had a significantly reduced right atrial active fractional area of emptying (p = 0.005), along with a reduced peak late diastolic strain rate (p = 0.002). Among 20 patients who underwent magnetic resonance tomographic examination, a relatively higher right atrial peak late diastolic strain rate was shown in patients with a right ventricular ejection fraction of less than 50% (p = 0.021). Right atrial performance is reduced in patients after surgical correction of tetralogy of Fallot. When facing right ventricular systolic dysfunction, nonetheless, the right atrial pump function may be relatively enhanced. Tissue Doppler derived strain rate can provide quantitative analysis of regional right atrial performance.