Tissue Doppler echocardiographic evidence of atrial mechanical dysfunction in coronary artery disease

Fine tuning contractility: atrial sarcomere function in health and disease

The molecular mechanisms of sarcomere proteins underlie the contractile function of the heart. Although our understanding of the sarcomere has grown tremendously, the focus has been on ventricular sarcomere isoforms due to the critical role of the ventricle in health and disease. However, atrial-specific or -enriched myofilament protein isoforms, as well as isoforms that become expressed in disease, provide insight into ways this complex molecular machine is fine-tuned. Here, we explore how atrial-enriched sarcomere protein composition modulates contractile function to fulfill the physiological requirements of atrial function. We review how atrial dysfunction negatively affects the ventricle and the many cardiovascular diseases that have atrial dysfunction as a comorbidity. We also cover the pathophysiology of mutations in atrial-enriched contractile proteins and how they can cause primary atrial myopathies. Finally, we explore what is known about contractile function in various forms of atrial fibrillation. The differences in atrial function in health and disease underscore the importance of better studying atrial contractility, especially as therapeutics currently in development to modulate cardiac contractility may have different effects on atrial sarcomere function.

Study the relationship between left atrial (LA) volume and left ventricular (LV) diastolic dysfunction and LV hypertrophy: Correlate LA volume with cardiovascular risk factors

Heart failure (HF) with normal ejection fraction - the isolated diastolic heart failure, depicts increasing prevalence and health care burden in recent times. Having less mortality rate compared to systolic heart failure but high morbidity, it is evolving as a major cardiac concern. With increasing clinical use of Left atrial volume (LAV) quantitation in clinical settings, LAV has emerged as an important independent predictor of cardiovascular outcome in HF with normal ejection fraction. This article is intended to review the diastolic and systolic heart failure, their association with left atrial volume, in depth study of Left atrial function dynamics with determinants of various functional and structural changes.

Heart function by M-mode and tissue Doppler in the early neonatal period in neonates with fetal growth restriction

BACKGROUND

Fetal growth restricted (FGR) neonates have increased risk of circulatory compromise due to failure of normal transition of circulation after birth.

AIM

Echocardiographic assessment of heart function in FGR neonates first three days after birth.

STUDY DESIGN

Prospective observational study.

SUBJECTS

FGR- and non-FGR neonates.

OUTCOME MEASURES

M-mode excursions and pulsed-wave tissue Doppler velocities normalised for heart size and E/e' of the atrioventricular plane day one, two and three after birth.

RESULTS

Compared with controls (non-FGR of comparable gestational age, n = 41), late-FGR (gestational age ≥ 32 weeks, n = 21) exhibited higher septal excursion (15.9 (0.6) vs. 14.0 (0.4) %, p = 0.021) (mean (SEM)) and left E/e' (17.3 (1.9) vs.11.5 (1.3), p = 0.019). Relative to day three, indexes on day one were higher for left excursion (21 (6) % higher on day one, p = 0.002), right excursion (12 (5) %, p = 0.025), left e' (15 (7) %, p = 0.049), right a' (18 (6) %, p = 0.001), left E/e' (25 (10) %, p = 0.015) and right E/e' (17 (7) %, p = 0.013), whereas no index changed from day two to day three. Late-FGR had no impact on changes from day one and two to day three. No measurements differed between early-FGR (n = 7) and late-FGR.

CONCLUSIONS

FGR impacted neonatal heart function the early transitional days after birth. Late-FGR hearts had increased septal contraction and reduced left diastolic function compared with controls. The dynamic changes in heart function between first three days were most evident in lateral walls, with similar pattern in late-FGR and non-FGR. Early-FGR and late-FGR exhibited similar heart function.

Strain and strain rate echocardiographic imaging predict occurrence of atrial fibrillation in post-coronary artery bypass grafting patients

BACKGROUND

Atrial fibrillation (AF) occurs very frequently after coronary artery bypass grafting (CABG); it occurs in about 20-edictors can be used for the dedicatio40% of patients. It is associated with several adverse events. This study aimed to extrapolate a predictor for postoperative atrial fibrillation (POAF) occurrence which is reproducible and simple to be a part of routine echocardiography screening before CABG. This study included 89 patients scheduled for isolated coronary artery bypass surgery. History, clinical examination, and complete 2D echocardiography with LA speckle tracking analysis were done preoperatively. Patients were then followed up post-surgery for incidence of AF till discharge from the hospital. The patients were divided into 2 groups according to POAF occurrence.

RESULTS

Patients who developed postoperative AF had older age (P = 0.0032) and longer hospital stay (P = 0.021) and higher stroke incidence but statistically non-significant (14.3% vs 3.3%). The POAF patients showed less peak atrial longitudinal strain (PALS) value than non-POAF patients. The left atrial strain rate values showed a significant difference with the lower left atrial systolic strain rate and less negative (higher) early diastolic strain rate and late diastolic strain rate. After multivariate logistic regression analysis, the independent predictors for POAF were PALS (OR 0.770, 95% CI 0.627-0.946), late LA diastolic strain rate (LASRa) (OR 3.476, 95% CI 1.207-12.186), and age (OR 1.181, 95% CI 1.011-1.379).

CONCLUSION

Preoperative LA global strain assessed by 2D speckle tracking analysis could be helpful as a predictor for AF post-CABG surgery, and identification of these patients may reduce its morbidity and mortality. The study suggested PALS value less than 29.8 to be a predictor for the occurrence of POAF.

Assessment of left and right atrial geometrical changes in patients with stable coronary artery disease: Left and right atrial strain and strain rate imaging study

Objective

In patients with coronary artery disease (CAD), there are several studies that assessed the left ventricular (LV) function by strain (S) and strain rate (SR) imaging. The aim of this study is to evaluate the function of both atria in patients with CAD using strain and strain rate imaging, and to correlate this with the severity of CAD.

Methods

We conducted a prospective, single center case control study for 40 consecutive patients who presented to our department with chronic stable angina and were candidates for invasive coronary angiography. We enrolled patients from December 2013 to May 2014 and each patient was subjected to echocardiographic assessment of E/e' of mitral valve, left atrial volume index (LAVI), right atrial volume index (RAVI), and peak atrial longitudinal strain (es) and strain rate (SR) during LV systole. This was followed by invasive coronary angiography for assessment of the severity of CAD using Gensini score. Patients were classified according to angiographic results into 3 groups: Group I (Gensini score = zero), Group II (Gensini score > 0 and < 20) and Group III (Gensini score ≥ 20).

Results

There was no statistically significant difference between the three groups in either LA volumes (V_min, V_max) and distensibility with p value of 0.272, 0.126, and 0.243 respectively or RA volumes and distensibility with a p value of 0.671, 0.183, and 0.259 respectively. On the other hand, LA & RA systolic S and SR were significantly lower among CAD patients in comparison with the group of normal coronaries. Mean LA S and SR was decreased in group III than group II (15.97 ± 3.73, 21.8 ± 6.75 % and 1.11 ± 0.30, 1.81 ± 1.23 s^-1) with p value of 0.005&0.041 respectively. RA systolic S and SR were significantly lower in the 2 groups with CAD than the group with normal coronaries with a p value of 0.001 and 0.002 respectively.

Conclusion

In patients with CAD and normal EF, borderline E/e' ratio and normal atrial size, there are decreased LA and RA systolic S and SR parameters with no effect on atrial volumes or distensibility. Accordingly, this could prove that atrial wall deformation occurs early in CAD even before any changes in atrial volumes or dimensions.

The transverse four-chamber view for the assessment of atrial tissue deformation in the fetus

AIMS

To determine if atrial tissue deformation (peak strain, PS) and time to peak strain (TTPS) can be assessed in the fetus, with identification of best echocardiographic plane.

MATERIALS AND METHODS

Pulsed-wave tissue Doppler study of a longitudinal and a transverse four-chamber view (FCV) in each of 20 healthy fetuses. Determination of PS and TTPS in regions of interest (ROI), viz., lateral walls of the right and left atria (RA, LA); comparison of values depending on section plane, with results-based discussion of the physiology of fetal atrial deformation and of possible clinical uses.

RESULTS

PS and TTPS could be determined on transverse FCV in 91% of subjects and in 61% on longitudinal FCV. Transverse PS and TTPS were significantly higher than longitudinal (p = 0.0001). Transverse PS was significantly higher in RA than in LA (26.9% vs. 17.3%, p = 0.034), and transverse TTPS was significantly shorter in RA than in LA (p = 0.034).

CONCLUSION

Atrial radial PS and TTPS determinations are possible in the fetus. The transverse FCV is best suited for these. The highest PS values and shortest TTPS values are found in ROI representing the RA. Our findings may contribute to detailed intrauterine assessment of atrial and ventricular myocardial function.

Decreased left atrial myocardial strain in patients with suboptimal blood pressure control

BACKGROUND

Suboptimal blood pressure (BP) control is commonly observed in patients receiving antihypertensive agents, but the relationship between uncontrolled BP and left atrial (LA) impairment remains unknown.

METHODS

This study enrolled 279 hypertensive patients who had been medicated, as well as 85 matched normal controls. The BP of systolic <140 mmHg and diastolic<90 mmHg was defined as optimal (HT1 group, n=146), otherwise as suboptimal BP control (HT2 group, n = 133). LA myocardial function was assessed by the systolic (S_Sa), early diastolic (S_Ea), and late diastolic (S_Aa) LA strains.

RESULTS

Both the HT1 group and HT2 group had higher BP reading, thicker interventricular septum, larger LA volume index, and enhanced active atrial emptying fraction than the control group (all <0.05). When compared with normal subjects, hypertensive patients displayed obvious reduction in the S_Sa (50.0 ± 10.9 vs. 35.9 ± 8.0%), S_Ea (30.1 ± 7.7 vs. 18.5 ± 7.1%) and S_Aa (19.9 ± 6.4 vs. 17.8 ± 4.2%) (all p < 0.001). In addition to a further impaired S_Ea found in the HT2 group than in the HT1 group (17.2 ± 5.3 vs. 19.8 ± 8.3%, p = 0.002), the treated BP of >140/90 mmHg appeared an independent risk factor associated with the abnormal S_Ea (odds ratio, 2.957; interval of confidence, 1.614-5.415; p = 0.001).

CONCLUSIONS

Suboptimal BP control status in hypertensive patients is related to a further reduction of LA myocardial function assessed by the novel 2DSTI free strain, and suboptimal BP might be regarded as a composite risk factor and therefore a simplified treatment target. However, the prognostic value of LA free strain in patients with inability to achieve the BP target needs to be evaluated in future prospective studies.

Early Transthoracic Echocardiography after Cardiac Surgery Predicts Postoperative Atrial Fibrillation

PURPOSE

Postoperative atrial fibrillation (POAF) is frequent after cardiac surgery. We aimed to establish a predictive model of POAF based on postoperative transthoracic echocardiography (TTE) findings.

METHODS

This study included 147 patients (aged 67 ± 11 years; 109 men) undergoing coronary artery bypass grafting and/or aortic valve replacement. TTE and Doppler tissue imaging were performed on intensive care unit arrival after surgery. All patients were continuously monitored during hospitalization. The end point was the appearance of POAF.

RESULTS

POAF appeared in 37 patients (25.2%). These patients were older (69 ± 16 vs. 65 ± 12 years; P < 0.001) and had increased long axis of the left atrium (LA) dimension (5.4 ± 1 vs. 4.8 ± 0.9 cm, P = 0.02), lower early diastolic velocity of the mitral annulus (e') (6.9 ± 2.1 vs. 8 ± 1.8 cm/sec; P < 0.01), and higher early diastolic pulsed Doppler mitral ratio (E)/e' (E/e') (17.4 ± 6.8 vs. 13.8 ± 6; P = 0.01). Left ventricle diastolic dysfunction grade (DFG) of 2 or 3 relative to grade 0 was significant: odds ratio (OR) 22.5, 95% confidence interval (CI) 4.52-57.2; P < 0.001, and OR: 23.6, 95% CI: 3.57-60.1; P = 0.001), respectively. On multivariate analysis, the independent predictors of POAF were age (OR: 1.10, 95% CI: 1.01-1.18; P < 0.05), long-axis LA dimension (OR: 6.24, 95% CI: 1.97-8.23; P = 0.0017), DFG-2 (OR: 4.1, 95% CI: 1.57-15.81; P < 0.001), and DFG-3 (OR: 8.3, 95% CI: 4.11-25.37; P < 0.001).

CONCLUSIONS

Apart from age, the simple determination by postoperative TTE of long-axis LA dimension and DFG after cardiac surgery proved to be powerful independent predictors of POAF and may be useful for risk stratification of these patients.

Improvement in left ventricular function assessed by tissue Doppler imaging after aortic valve replacement for severe aortic stenosis

INTRODUCTION

The effects of reduction of left ventricular (LV) systemic afterload following aortic valve replacement (AVR) for severe aortic valve stenosis (AS) were investigated, using echocardiography and tissue Doppler imaging (TDI).

METHODS

We compared the preoperative and postoperative echocardiographic assessments of 23 patients with severe AS who had undergone isolated AVR (n = 13) or concomitant AVR with coronary artery bypass grafting (CABG) (n = 10). Conventional echocardiographic evaluations and TDI at the lateral mitral annulus were performed.

RESULTS

Echocardiography was performed at a median of 120 (interquartile range: 66-141) days after AVR. There was significant reduction in aortic transvalvular mean pressure gradient after AVR. Although LV dimensions, mass and ejection fraction remained unchanged, LV diastolic and systolic functions improved (as observed on TDI). Early diastolic (E'), late diastolic (A') and systolic (S') mitral annular velocities increased significantly (p < 0.05). There was significant improvement in TDI-derived parameters among the patients who had isolated AVR, while among the patients who had concomitant AVR with CABG, only S' had significant improvement (p = 0.028).

CONCLUSION

TDI was able to detect improvements in LV systolic and diastolic function after AVR for severe AS. There was less improvement in the TDI-derived diastolic parameters among patients who underwent concomitant AVR with CABG than among patients who underwent isolated AVR.

Evaluation of right ventricular function in fetuses with hypoplastic left heart syndrome using tissue Doppler techniques

OBJECTIVE

The outcome of patients with hypoplastic left heart syndrome (HLHS) is influenced by right ventricular function. This study aimed to investigate whether differences in right ventricular function of fetuses with HLHS are present during gestation.

METHODS

This was a prospective study comprising 14 fetuses with HLHS (28 measurements obtained in total) and 28 normal control fetuses (31 measurements obtained in total). The two groups were matched for gestational age. Ultrasound M-mode was used to assess displacement of the tricuspid annulus. Spectral Doppler and myocardial tissue Doppler-derived inflow and outflow velocities were assessed. Tricuspid valve peak early wave to peak active wave (E/A) ratio, the early wave to early diastolic annular relaxation velocity (E/E') ratio and the tissue Doppler-derived myocardial performance index (MPI') were calculated.

RESULTS

E-wave velocity was significantly higher in fetuses with HLHS than in control fetuses (mean, 40.14 cm/s vs 35.47 cm/s; P < 0.05, respectively), and A-wave velocity in fetuses with HLHS showed a tendency for higher values in the right ventricle compared with normal control fetuses, but this did not reach statistical significance (61.16 cm/s vs 54.64 cm/s; P = 0.08). The E/A ratio increased during gestation in controls, but this increase was not seen in HLHS fetuses. Peak annular velocity during atrial contraction (A') and the E/E' ratio were significantly lower in controls than in HLHS fetuses: 9.50 cm/s vs 10.39 cm/s (P < 0.05) and 5.77 vs 7.37 (P < 0.05), respectively. There were no differences for right-ventricular MPI' or tricuspid annular plane systolic excursion between HLHS fetuses and controls.

CONCLUSION

The results of this study show that altered right ventricular function in HLHS infants may develop antenatally. It is hoped that confirmation of these findings using Doppler-independent techniques will lead to further exploration of ventricular function in HLHS fetuses. Consequently, parental counseling and postnatal management strategies could be influenced.

Principles of transthoracic echocardiographic evaluation

Transthoracic echocardiography is the most widely used imaging test in cardiology. Although completely noninvasive, transthoracic echocardiography has a well-established role in the diagnosis of numerous cardiovascular diseases, and also provides critical qualitative and quantitative information on their prognosis and pathophysiological processes. The aim of this Review is to outline the broad principles of transthoracic echocardiography, including the traditional techniques of two-dimensional, colour, and spectral Doppler echocardiography, and newly developed advances including tissue Doppler, myocardial deformation imaging, torsion, stress echocardiography, contrast and three-dimensional echocardiography. The advantages and disadvantages, clinical application, prognostic value, and salient research findings of each modality are described. Advances in complex imaging techniques are expected to continue unabated, and this Review highlights technical improvements that will influence the diagnosis and improve our understanding of cardiovascular function and disease.

NT-proBNP as early marker of subclinical late cardiotoxicity after doxorubicin therapy and mediastinal irradiation in childhood cancer survivors

Background. Childhood cancer survivors treated with anthracyclines and mediastinal irradiation are at risk for late onset cardiotoxicity. Aims of the Study. To assess the role of N-terminal pro-brain natriuretic peptide (NT-proBNP) and tissue Doppler imaging (TDI) as early predictors of late onset cardiotoxicity in asymptomatic survivors of childhood cancer treated with doxorubicin with or without mediastinal irradiation. Methods. A cross-sectional study on 58 asymptomatic survivors of childhood cancer who received doxorubicin in their treatment protocols and 32 asymptomatic Hodgkin's lymphoma survivors who received anthracycline and mediastinal irradiation. Levels of NT-proBNP, TDI, and conventional echocardiography were determined. Results. Thirty percent of survivors had abnormal NT-proBNP levels. It was significantly related to age at diagnosis, duration of follow-up, and cumulative dose of doxorubicin. TDI detected myocardial affection in 20% more than conventional echocardiography. Furthermore, abnormalities in TDI and NT-pro-BNP levels were more common in Hodgkin lymphoma survivors receiving both chemotherapy and radiotherapy. Conclusions. TDI could detect early cardiac dysfunction even in those with normal conventional echocardiography. Measurement of NT-proBNP represents an interesting strategy for detecting subclinical cardiotoxicity. We recommend prospective and multicenter studies to validate the role of NT-proBNP as an early marker for late onset doxorubicin-induced cardiotoxicity.

Left atrial geometry and pump function in ischemic cardiomyopathy

Background

Many of the factors that are known to alter left atrial (LA) contractility are present in patients with ischemic cardiomyopathy (ICM). Nevertheless, preservation of LA contractile function in this group of patients was reported in previous studies. The aim of this study was to assess the changes in LA size, geometry and contractile function in ICM.

Methods and results

60 subjects (age: 49 ± 12 years, 53% males) in sinus rhythm undergoing coronary angiography (CA), were enrolled in this study; 15 subjects as a control group, 30 patients with reduced ejection fraction (EF) and significant coronary artery disease; as the ICM group, and 15 with reduced EF and normal CA; as the dilated cardiomyopathy (DCM) group.

LA dimensions, volume, active emptying fraction (ACTEF) and eccentricity index (LAEi) as well as late diastolic velocities of the mitral annulus (a′) and LA free wall (A₃) were measured.

Compared with the control group, ICM patients had larger LA volume and reduced ACTEF, a′ and A₃, with no significant difference between patients with ICM and DCM in any of these parameters. LA eccentricity was, non-significantly, higher in both cardiomyopathy groups than in the control group.

Conclusions

Patients with ICM have increased LA volume and reduced LA contractile function in comparison with normal controls. LA enlargement, LA contractile dysfunction and LA geometric changes in ICM are similar to that occurring in DCM. LA size, contractile function and eccentricity may not be reliable in differentiating ischemic from idiopathic dilated cardiomyopathy.

Clinical and echocardiographic predicators of postoperative atrial fibrillation

BACKGROUND

Postoperative atrial fibrillation is the most common arrhythmia after coronary artery bypass grafting, with a reported incidence of 10% to 60%. Preoperative clinical and echocardiographic data, especially the atrial electromechanical interval, predict postoperative atrial fibrillation in elective coronary artery bypass patients.

METHODS

A prospective study evaluated preoperative clinical and echocardiographic data in 192 patients who underwent elective coronary artery bypass from 2010 to 2012.

RESULTS

18 (9.37%) patients developed postoperative atrial fibrillation. Compared to patients without postoperative atrial fibrillation, these 18 had significantly longer intensive care unit and hospital stays, they were significantly older (58.62 ± 10.02 vs. 53.22 ± 8.23 years; p = 0.02), with a larger left atrial volume (83.39 ± 8.31 vs. 55.47 ± 8.37 cm(3), p = 0.001), longer atrial electromechanical interval (133.67 ± 8.15 vs. 98.05 ± 6.71 ms p < 0.0001), and lower tissue Doppler imaging systolic velocity wave amplitude (6.6 ± 1 vs. 9.4 ± 2.2 cm·s(-1); p = 0.001); they also had a higher prevalence of hypertension (61.11% vs. 38.5%; p = 0.04). Using 115 ms as the cutoff value of atrial electromechanical interval enabled us to detect patients who developed postoperative atrial fibrillation with 100% sensitivity, 77% specificity, 78% positive predictive value, and 100% negative predictive value.

CONCLUSION

Older hypertensive patients are at higher risk of developing postoperative atrial fibrillation. Preoperative measurement of atrial electromechanical interval by tissue Doppler echocardiography is a useful predictor of postoperative atrial fibrillation in coronary artery bypass patients.

Evaluation of biatrial size and functions by different echocardiographic parameters in patients with acute coronary syndromes

After acute coronary syndromes (ACS), cardiac remodelling affecting not only ventricles but also both atria is an important problem associated with an increased risk for adverse cardiovascular outcomes. However, it is usually underestimated to evaluate atrial size and functions. The aim of the present study is to compare left and right atrial size and functions in ACS patients with healthy controls during transthoracic echocardiography by means of diameter, area and volume measurements, and pulsed-wave tissue Doppler imaging (TDI). 150 ACS patients (128 male, 22 female) and 25 healthy controls (19 male, 6 female) were enrolled into the study. Of the ACS patients, 75 had ST-segment elevation myocardial infarction (STEMI) and 75 had non-STEMI. Biatrial diameters, areas, and volumes were measured from different echocardiographic views. Atrial total emptying fraction and expansion index values were calculated from volume measurements. By the pulsed-wave TDI of the atrial walls; peak systolic (S'), peak early diastolic (E'), and peak late diastolic (A') velocities were measured. Almost all left atrial parameters for diameter, area, and volume measurements were higher in ACS patients. Similarly, they had higher values for the same right atrial parameters. Left and right atrial total emptying fraction and expansion index values were lower in ACS patients than controls. All left and right atrial walls had lower S' and E' velocities in ACS patients. ACS cause important alterations in the biatrial size and functions evaluated by echocardiographic diameter, area and volume measurements, and pulsed-wave TDI.

Positive end-expiratory pressure aggravates left ventricular diastolic relaxation further in patients with pre-existing relaxation abnormality

BACKGROUND

Positive end-expiratory pressure (PEEP) has been known to adversely influence cardiac output. Even though left ventricular (LV) diastolic function significantly contributes to LV performance, the effects of PEEP on LV diastolic function remains controversial. We, therefore, aimed to examine the effects of PEEP on LV diastolic function by use of pulsed wave Doppler tissue imaging in patients with pre-existing LV relaxation abnormality.

METHODS

Seventeen patients with peak early diastolic velocity of lateral mitral annulus (E') <8.5 cm s(-1) among patients who underwent coronary artery bypass graft surgery were evaluated. Echocardiographic and haemodynamic variables were measured with 0, 5, and 10 cmH2O of PEEP. E' and deceleration time (DT) of peak early transmitral filling velocity (E) were used as echocardiographic indicators of LV diastolic function.

RESULTS

Mean arterial blood pressure decreased during 10 cmH2O PEEP, compared with that during 0 cmH2O PEEP. E' showed a gradual and significant decrease with an incremental increase in PEEP (6.9 ± 0.9, 5.8 ± 0.9, and 5.2 ± 1.2 cm s(-1) during 0, 5, and 10 cmH2O PEEP, respectively), and DT of E was prolonged during 10 cmH2O PEEP, compared with that during 0 cmH2O PEEP.

CONCLUSIONS

Increasing PEEP led to a progressive decline in LV relaxation in patients with pre-existing LV relaxation abnormality.

Mitral annular velocity in patients with postoperative atrial fibrillation

BACKGROUND

Subclinical atrial stunning (AS) (left atrial dysfunction) may increase vulnerability to oxidative and inflammatory stressors, thus increasing the likelihood of postoperative supraventricular arrhythmias, especially atrial fibrillation (AF). Evaluation of mitral annular velocities by tissue Doppler imaging (TDI) may be useful in seeking subclinical AS. This prospective study aimed to evaluate the relationship between atrial fibrillation after bypass surgery and presurgical determination of subclinical AS by assessing mitral annular velocities by TDI.

METHODS

We enrolled patients who underwent coronary artery bypass graft (CABG) surgery into this prospective study. Inclusion criteria were sinus rhythm and a negative history of atrial tachycardia during the previous 3 mo. An experienced cardiologist performed transthoracic echocardiography in all patients. We recorded standard two-dimensional, mitral inflow conventional Doppler interrogation and TDI pulsed wave data from the lateral and septal annulus. All patients underwent CABG surgery at our Cardiovascular Surgery Unit. Patients were divided into two groups based on their postoperative AF status: group 1 patients had postoperative AF and group 2 patients did not.

RESULTS

This study included 44 patients. Age and the presence of chronic obstructive pulmonary disease were the only two significantly different parameters among clinical characteristics between groups. Echocardiographic findings that were statistically significantly different between groups were as follows: lateral A diastolic mitral annular velocity, group 1: 0.11 ± 0.19 ms(-1)versus group 2: 0.08 ± 0.19 ms(-1) (P = 0.001); lateral E diastolic mitral annular velocity, group 1: 0.69 ± 0.24 ms(-1)versus group 2: 0.62 ± 0.31 ms(-1) (P = 0.016); Septal E diastolic mitral annular velocity, group 1: 0.05 ± 0.01 ms(-1)versus group 2: 0.04 ± 0.01 ms(-1) (P = 0.033); septal A diastolic mitral annular velocity, group 1: 0.08 ± 0.02 ms(-1)versus group 2: 0.05 ± 0.02 ms(-1) (P = 0.005).

CONCLUSIONS

There is no relationship between AF after CABG surgery and preexisting subclinical AS determined with mitral annular velocities by TDI. Preoperative appropriate prophylactic treatment should be administered to all patients.

Functional assessment of the fetal heart: a review

The purpose of this review is to evaluate the current modalities available for the assessment of fetal cardiac function. The unique anatomy and physiology of the fetal circulation are described, with reference to the difference between in-utero and ex-utero life. M-mode, early/atrial ratio, myocardial performance index, three-dimensional and four-dimensional ultrasound, tissue Doppler including strain and strain rate, speckle tracking, magnetic resonance imaging and venous flow assessment are described. The modalities are analyzed from the perspective of the clinician and certain questions are posed. Does the modality assess systolic function, diastolic function or both? Is it applicable to both ventricles? Does it require extensive post-processing or additional hardware, or does it make use of technology already available to the average practitioner? The reproducibility and reliability of the techniques are evaluated, with reference to their utility in clinical decision-making. Finally, directions for future research are proposed.

Left atrial function: physiology, assessment, and clinical implications

The interest in the left atrium (LA) has resurged over the recent years. In the early 1980s, multiple studies were conducted to determine the normal values of LA size. Over the past decade, LA size as an imaging biomarker has been consistently shown to be a powerful predictor of outcomes, including major public health problems such as atrial fibrillation, heart failure, stroke, and death. More recently, functional assessment of the LA has been shown to be, at least as, if not more robust, a marker of cardiovascular outcomes. Current available data suggest that the combined evaluation of LA size and LA function will augment prognostication. The aim of this review is to provide a critical appraisal of current echocardiographic techniques for the assessment of LA function and the implications of such assessment for prediction and disease prevention.

The effects of spironolactone on atrial remodeling in patients with preserved left ventricular function after an acute myocardial infarction: a randomized follow-up study

OBJECTIVES

Atrial remodeling is an important part of cardiac remodeling after acute myocardial infarction (AMI). The aim of this study was to evaluate the effect of spironolactone on atria in patients with preserved left ventricular (LV) functions after AMI by using two-dimensional and tissue Doppler imaging techniques (TDI).

METHODS

The study consisted of 110 patients with AMI, successfully revascularized with percutaneous coronary intervention, ejection fraction greater than or equal to 40%, and Killip class I-II. Patients were randomized into two groups: conventional therapy (n=55) and additional spironolactone of 25 mg/day with standard conventional therapy (n=55). Echocardiography was performed in the first 48-72 h of AMI and during 6 months of follow-up. Left atrial volume index and emptying fraction were obtained. The peak regional atrial contraction velocity, the time between the onset of p-wave on the monitor ECG and the onset, peak, and the end (TE) of the atrial contraction wave on the tissue Doppler technique curve were measured.

RESULTS

The left atrial volume index and left atrium (LA) dimensions did not significantly change in either group. In the spironolactone group, left atrial emptying fraction increased compared with both baseline value (from 53.0 ± 0.16 to 57.0 ± 0.13 P=0.011) and conventional therapy group (from 50.0 ± 0.17 to 47.0 ± 0.16, P=0.013). The atrial contraction velocity did not change but the LA-TE, interatrial septum-TE, and right atrium-TE were prolonged in the conventional therapy group.

CONCLUSION

Additional spironolactone therapy provided a little benefit on LA remodeling and atrial electromechanic properties in patients with AMI and preserved LV functions.

Comparison of left atrial phasic function in hypertrophic cardiomyopathy versus systemic hypertension using strain rate imaging

The aim of this study was to determine if left atrial (LA) phasic function evaluated by Doppler tissue imaging-derived strain and strain rate would be differentially decreased in patients with hypertrophic cardiomyopathy (HC) compared to patients with hypertension and to normal controls. Thirty-seven patients with HC were compared to 44 patients with systemic hypertension (SH) and 65 normal controls using transthoracic echocardiography. Maximal and minimal LA volume and LA volume just before active atrial contraction (pre-P LA volume) were measured, and phasic LA volumes were calculated. Global and segmental systolic strain rate, early diastolic strain rate, and late diastolic strain rate (A-Sr) and strain were measured from Doppler tissue imaging. Left ventricular mass was increased in the HC and SH groups compared to normal controls, but diastolic dysfunction was greater in the HC group. LA volumes were increased in patients with HC compared to those with SH and to normal controls, with corresponding reductions in A-Sr and atrial strain in the HC group. In contrast, only early diastolic strain rate was decreased in the SH group compared to controls. A-Sr remained reduced in patients with HC compared to the SH group, even after adjusting for left ventricular mass. When left ventricular mass, parameters of diastolic function (peak E and E' velocity), and the effect of patient group (SH vs HC) were examined in a stepwise regression model, patient group (SH vs HC) was the only independent determinant of A-Sr. In conclusion, HC results in LA enlargement with reduced LA phasic function that is reflected in reductions in A-Sr and atrial strain. Atrial enlargement is a likely consequence of the greater diastolic dysfunction in the HC group.

Left atrial dysfunction and new-onset atrial fibrillation after cardiac surgery

INTRODUCTION AND OBJECTIVES

Postoperative atrial fibrillation is a common complication of carrying out cardiac surgery with extracorporeal circulation (ECC). The aim of this study was to determine whether preoperative left atrial contractile dysfunction, as assessed by tissue Doppler echocardiography, is associated with the development of postoperative new-onset atrial fibrillation (PAF).

METHODS

Transthoracic Doppler echocardiography was performed preoperatively in patients undergoing elective cardiac surgery. Left atrial contractile function was evaluated by tissue Doppler imaging (TDI) of the mitral annulus.

RESULTS

The study included 92 patients in sinus rhythm preoperatively who underwent elective cardiac surgery with ECC: 73 (79%) were male and 19 (21%) were female, and their mean age was 67 (10) years. Of these, 19 (20.6%) developed PAF 34 (12) h postoperatively. Bivariate analysis showed that PAF was associated with older age (71 [7] years vs 66 [10] years; P=.034), a large left atrial diameter (LAD), and a low peak atrial systolic mitral annular velocity (A velocity) and a high mitral E/A ratio on TDI. Logistic regression analysis showed that PAF was independently associated with a large LAD (odds ratio [OR] =2.23; 95% confidence interval [CI], 1.05-4.76; P=.033) and a low A velocity (OR=0.70; 95% CI, 0.55-0.99; P=.034).

CONCLUSIONS

Preoperative left atrial dysfunction, as assessed by TDI, was associated with an increased risk of PAF.

Differential recovery of regional atrial contraction after restoration of sinus rhythm after intraoperative linear radiofrequency ablation for atrial fibrillation

The aim of this study was to quantitate regional atrial contractility in patients with atrial fibrillation (AF) maintained in sinus rhythm after creating lines of block by intraoperative linear radiofrequency ablation for AF. We hypothesized that left atrial regional and global function remains impaired after radiofrequency ablation, despite restoration of sinus rhythm in this cohort. Patients with chronic AF maintained in sinus rhythm > or =6 months after radiofrequency ablation (n = 28) were studied and compared with a chronic AF group who, after standard electrical transthoracic cardioversion, were maintained in sinus rhythm for 6 months (n = 32) and a normal cohort (n = 32). Using color Doppler tissue imaging (CDTI), segmental atrial contraction was measured from annular, mid, and superior locations of the left atrium in both the apical 4- and 2-chamber views and of the right atrium in the apical 4-chamber view. Peak positive strain (SI) and atrial strain rate in early (E-sr) and late diastole (A-sr) were measured from mid and superior segments in both the apical 4- and 2-chamber views of the left atrium. The radiofrequency ablation group had significantly lower CDTI, SI, and A-sr values in all segments compared with both the cardioversion and normal groups. The cardioversion group had lower CDTI velocities than normal subjects. In the radiofrequency ablation group, CDTI velocities, SI, and A-sr values of the inferior and lateral segments were differentially and substantially lower than noted in other segments. In conclusion, patients with chronic AF have significant persistent left atrial dysfunction, despite restoration and maintenance of sinus rhythm. Additive global and regional atrial dysfunction was present in the radiofrequency ablation group suggestive of injury caused by the ablation process. These findings may have implications for selecting the duration of subacute and chronic anticoagulation after anatomic alteration of left atrial endocardium using radiofrequency ablation as a means of restoring sinus rhythm in chronic AF.

Approaching regional left atrial function by tissue Doppler velocity and strain imaging

Atrial function is an integral part for the proper performance of the circulatory system. Assessment of its haemodynamic and mechanical characteristics by use of non-invasive echocardiography, including tissue Doppler velocity and strain imaging, may provide a better insight into atrial function and its relationship with ventricular function. From an electromechanical perspective, this review summarizes not only the various methods for evaluating regional atrial function by tissue Doppler imaging, but also the normal findings in healthy subjects and the major clinical utilities in cardiac diseases, such as atrial fibrillation, ischaemic heart disease and heart failure.

Metabolic acidosis decreases fetal myocardial isovolumic velocities in a chronic sheep model of increased placental vascular resistance

We hypothesized that acute fetal metabolic acidosis decreases fetal myocardial motion in a chronic sheep model of increased placental vascular resistance ( Rua). Eleven ewes and fetuses were instrumented at 118–122 days of gestation. After 5 days of recovery and 24 h of placental embolization to increase Rua, longitudinal myocardial velocities of the right and left ventricles and interventricular septum (IVS) were assessed at the level of the atrioventricular valve annuli via tissue Doppler imaging (TDI). Ventricular inflow (E and A waves) and outflow velocities were obtained, and cardiac outputs were calculated. All measurements were performed at baseline and during fetal acidosis caused by epidural anesthesia-induced maternal hypotension, which decreased uterine artery volume blood flow, fetal oxygenation, arterial pH, and base excess and increased lactate. Compared with baseline, the peak isovolumic myocardial contraction and relaxation velocities of the ventricles and IVS, early relaxation velocity (E′) of the ventricles, and systolic velocity of the IVS decreased during metabolic acidosis. The proportion of isovolumic contraction time of the cardiac cycle increased but the isovolumic relaxation and ejection time proportions and the TDI Tei index did not change. The E-to-E′ ratio for both ventricles was higher during metabolic acidosis than at baseline. During metabolic acidosis, right and left ventricular cardiac outputs remained unchanged compared with baseline. In sheep fetuses with increased Rua and acute metabolic acidosis, global cardiac function was preserved. However, acute metabolic acidosis impaired myocardial contractility during the isovolumic phase and relaxation during the isovolumic and early filling phases of the cardiac cycle.

Improvement of Atrial Function and Atrial Reverse Remodeling After Cardiac Resynchronization Therapy for Heart Failure

OBJECTIVES

We sought to examine whether cardiac resynchronization therapy (CRT) improves atrial function and induces atrial reverse remodeling.

BACKGROUND

Cardiac resynchronization therapy is an established therapy for advanced heart failure with prolonged QRS duration, which improves left ventricle (LV) function and is associated with LV reverse remodeling.

METHODS

A total of 107 heart failure patients (66 +/- 11 years) who received CRT and were followed up for 3 months were studied. Atrial function was assessed by M-mode, 2-dimensional echocardiography, transmitral Doppler, tissue Doppler velocity, and strain (epsilon) imaging. Left atrial (LA) emptying fraction based on the change in areas (LAA-EF) and volumes (LAV-EF) were calculated. The LV reverse remodeling was defined by a reduction of LV end-systolic volume >10%.

RESULTS

In the responders of LV reverse remodeling (n = 62), LAA-EF and LAV-EF were significantly increased (p < 0.001). Responders also had significant decrease in LA size area and volumetric measurements, both before (p < 0.05) and after atrial systole (p < 0.001). However, these parameters were unchanged in the nonresponders (n = 45, p = NS). In the responders, tissue Doppler velocity analysis showed improvement of contraction velocity in both left (p = 0.005) and right atria (p = 0.018), whereas epsilon in both atria were increased in all the phases of cardiac cycle, namely ventricular end-systole (p < 0.001), early diastole (p < 0.001), and late diastole (p = 0.007).

CONCLUSIONS

Cardiac resynchronization therapy improves both left and right atrial pump function. The increase in atrial epsilon throughout the cardiac cycle is likely reflecting the improvement of atrial compliance. These changes lead to LA reverse remodeling with reduction of LA size before and after atrial systole.

Tissue Doppler imaging a new prognosticator for cardiovascular diseases

Tissue Doppler imaging (TDI) is evolving as a useful echocardiographic tool for quantitative assessment of left ventricular (LV) systolic and diastolic function. Recent studies have explored the prognostic role of TDI-derived parameters in major cardiac diseases, such as heart failure, acute myocardial infarction, and hypertension. In these conditions, myocardial mitral annular or basal segmental (Sm) systolic and early diastolic (Ea or Em) velocities have been shown to predict mortality or cardiovascular events. In particular, those with reduced Sm or Em values of <3 cm/s have a very poor prognosis. In heart failure and after myocardial infarction, noninvasive assessment of LV diastolic pressure by transmitral to mitral annular early diastolic velocity ratio (E/Ea or E/Em) is a strong prognosticator, especially when E/Ea is > or =15. In addition, systolic intraventricular dyssynchrony measured by segmental analysis of myocardial velocities is another independent predictor of adverse clinical outcome in heart failure subjects, even when the QRS duration is normal. In heart failure patients who received cardiac resynchronization therapy, the presence of systolic dyssynchrony at baseline is associated with favorable LV remodeling, which in turn predicts a favorable long-term clinical outcome. Finally, TDI and derived deformation parameters improve prognostic assessment during dobutamine stress echocardiography. A high mean Sm value in the basal segments of patients with suspected coronary artery disease is associated with lower mortality rate or myocardial infarction and is superior to the wall motion score.

Atrial strain rate echocardiography can predict success or failure of cardioversion for atrial fibrillation: A combined transthoracic tissue Doppler and transoesophageal imaging study

AIMS

The purpose of this study was to assess the feasibility of measuring left atrial dysfunction with tissue Doppler imaging derived strain rate and to explore its role in predicting the maintenance of sinus rhythm after cardioversion for atrial fibrillation.

METHODS AND RESULTS

Strain rate (SR) and tissue Doppler imaging (TDI) were performed with offline analysis of the basal left atrial wall (LA). SR detected a systolic (Ssr) and early diastolic (Esr) deformation induced by ventricular motion. LA dimensions and volume were measured. Left atrial appendage emptying (LAA_EV) and filling (LAA_FV) velocities were also obtained by transesophageal echocardiography. 27 healthy age-matched controls and 42 patients with AF before cardioversion were studied. Patients were grouped into (1): those who remained in sinus rhythm (group S, n=12) and (2) those who either failed cardioversion or reverted to AF within 4 weeks (group F, n=30). LA dimensions were significantly larger and atrial Esr was significantly lower in group F than group S (all p<0.01). LAA_EV and LAA_FV were not different between groups S and F. Multivariate regression analysis showed that a lower Esr and larger transverse LA diameter (LADtr) were independent predictors of failure of cardioversion (HR, 95% CI: 0.36, 0.14-0.88 and 2.85, 1.33-6.10, respectively). Esr combined with LADtr improved the sensitivity and specificity for predicting successful cardioversion.

CONCLUSIONS

SR can be measured in the basal LA wall in atrial fibrillation and the magnitude of the early diastolic SR could predict the success of cardioversion and the likelihood of maintenance of sinus rhythm.

Clinical Utility of Tissue Doppler Imaging in Prediction of Atrial Fibrillation After Coronary Artery Bypass Grafting

BACKGROUND

Atrial systolic dysfunction in patients with coronary artery disease might influence the development of atrial fibrillation after coronary artery bypass grafting (CABG). Tissue Doppler imaging of the mitral annulus during atrial systole has proved to quantify, accurately, left atrial contractile function. Therefore, the aim of the present study was to investigate the correlation between preoperative left atrial dysfunction assessed by tissue Doppler and postoperative atrial fibrillation after CABG.

METHODS

We studied a total of 96 patients (mean age 67 +/- 6 years; range, 55 to 81) undergoing CABG who were preoperatively in sinus rhythm. All patients underwent a preoperative transthoracic echocardiography with tissue Doppler evaluation. Until the day of discharge, all patients were monitored with continuous electrocardiographic telemetry.

RESULTS

There were no hospital deaths. Postoperative atrial fibrillation was recorded in 24 of 96 patients (25%). Patients with postoperative atrial fibrillation were significantly older (70 +/- 6 vs 65 +/- 8 years; p = 0.006), had a preoperative larger left atrium diameter (38 +/- 5 vs 36 +/- 4 mm; p = 0.045), a larger left atrium area (13.2 +/- 3.4 vs 11.5 +/- 2.3 cm2; p = 0.007), and a lower peak atrial systolic mitral annular tissue Doppler velocity (10 +/- 3 vs 13 +/- 5 cm/second; p = 0.01). Stepwise logistic regression analysis showed that age 70 years or greater (p = 0.02; odds ratio [OR] 2.0), preoperative medication with beta-blockers (p = 0.04; OR 0.7), left atrium area 13 cm2 or greater (p = 0.02; OR 2.5), and peak atrial systolic mitral annular tissue Doppler velocity 9 cm/second or less (p = 0.03; OR 1.8) were independently related with the incidence of postoperative atrial fibrillation.

CONCLUSIONS

Tissue Doppler is useful for assessing preoperative atrial dysfunction and predicting atrial fibrillation after CABG. Further studies are needed to confirm this finding.

Effect of Age and Heart Rate on Atrial Mechanical Function Assessed by Doppler Tissue Imaging in Healthy Individuals

BACKGROUND

The potential usefulness of Doppler tissue imaging (DTI) to assess atrial mechanical function in cardiac disease has been demonstrated. However, there are few reports on normal values of atrial function by DTI analysis.

METHODS

Echocardiography with color-coded DTI was performed in 131 healthy control subjects. The peak atrial contraction velocity (V(A)) and the timing of mechanical events were assessed offline at the left atrial (LA) and right atrial (RA) free wall and interatrial septum.

RESULTS

V(A) was higher in the RA (9.0 +/- 2.6 cm/s) than the LA (7.5 +/- 2.4 cm/s, P < .001), and both sites were higher than the interatrial septum (5.6 +/- 1.3 cm/s, both P < .001). The interatrial delay was 24 +/- 21 milliseconds. V(A) at the LA was higher in the participants aged 60 years or older than those who were younger than 60 years (8.1 +/- 2.7 vs 6.7 +/- 1.4 cm/s, P < .001), as was the velocity at the RA (9.6 +/- 2.8 vs 8.0 +/- 2.1 cm/s, P < .01). V(A) at the LA was higher in the participants with heart rate of 60/min or higher than those with lower heart rate (7.9 +/- 2.5 vs 6.8 +/- 1.8 cm/s, P < .05). Sex difference had no effect on V(A) and timings of atrial events.

CONCLUSIONS

Assessment of atrial mechanical function by DTI is feasible in healthy individuals. The V(A) is the highest at the RA, followed by LA, and the lowest at the interatrial septum. Older age and faster heart rate seems to augment V(A) in the atrial walls.