Assessment of Atrial Function

Echocardiography predictors of sustained sinus rhythm after cardioversion of supraventricular arrhythmia in patients with septic shock

PURPOSE

The echocardiography parameters may predict the maintenance of sinus rhythm after cardioversion of a supraventricular arrhythmia (SVA).

MATERIALS AND METHODS

Patients in septic shock with onset of an SVA, normal to moderately reduced LV systolic function (EF_LV˃̳35%) and on a continuous noradrenaline of <1.0 μg/kg.min were included. Echocardiography was performed at the arrhythmia onset, 1 h and 4 h post cardioversion on an infusion of propafenone or amiodarone.

RESULTS

Cardioversion was achieved in 96% of the 209 patients within a median time of 6(1.8-15.6)h, 134(64.1%) patients experienced at least one SVA recurrence after cardioversion. At 4 h the left atrial emptying fraction (LA_EF, cut-off 38.4%, AUC 0.69,p˂0.001), and transmitral A wave velocity-time-integral (Avti, cut-off 6.8 cm, AUC 0.65,p = 0.001) showed as limited predictors of a single arrhythmia recurrence. The LA_EF 44(36,49)%, (p = 0.005) and the Avti 8.65(7.13,9.50)cm, (p < 0.001) were associated with sustained sinus rhythm and decreased proportionally to increasing numbers of arrhythmia recurrences (p < 0.001 and p = 0.007, respectively). The enlarged left atrial end-systolic diameter at the arrhythmia onset (p = 0.04) and elevated systolic pulmonary artery pressure at 4 h (p = 0.007) were weak predictors of multiple(˃3) recurrences.

CONCLUSION

The LA_EF and Avti are related to arrhythmia recurrences post-cardioversion suggesting potential guidance to the choice between rhythm and rate control strategies.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03029169, registered on 24th of January 2017.

Five-Year Outcomes of Concomitant Maze Procedure Using Nitrous Oxide versus Argon-Based Cryoablation

BACKGROUND

Cryoablation is effective for ablating the myocardium but maintaining the structure of the ablated tissue. However, data comparing nitrous oxide (N₂O)-based and argon gas-based cryoprobes are limited.

METHODS

This study was a follow-up study of a single-center, prospective, randomized controlled trial in which 60 patients were randomly allocated to either the N₂O group or the argon group. The primary endpoint of this study was sinus rhythm maintenance, and the key secondary endpoint was a composite of major adverse cardiovascular and cerebrovascular events (MACCEs) (i.e., cardiac death, stroke, major bleeding, and readmission for heart failure).

RESULTS

The baseline and operative characteristics of the patients in the N₂O and argon groups were comparable. At the 5-year follow-up, the rate of sinus rhythm maintenance was 81.8% in the N₂O group, whereas it was 78.5% in the argon group (p > 0.999). No significant differences in the rate of freedom from MACCEs (80.6% in the N₂O group vs. 81.9% in the argon group; P = .978) was observed at the 5-year follow-up. The left atrial volume index decreased over time from 114.65 mL/m² to 65.74 mL/m² (P < .0001) and reached similar values in the two groups (P = .279) at the 5-year follow-up.

CONCLUSIONS

Both N₂O- and argon gas-based cryoprobes showed similar rates of sinus rhythm maintenance and freedom from MACCEs at the 5-year follow-up. Both cryoprobes might have similar efficacy and safety in the arrested heart in the long term.

Role of speckle tracking echocardiography in detecting early left atrial dysfunction in hypertensive patients

Background

Arterial hypertension adversely affects left atrial (LA) size and function, effect on function may precede effect on size. Many techniques were used to assess LA function but with pitfalls.

Objectives

Early detection of left atrial dysfunction with speckle tracking echocardiography in hypertensive patients with normal left atrial size.

Patients and methods

The study was conducted on 50 hypertensive patients and 50 age matched normotensive controls, all with normal LA volume index and free from any other cardiovascular disease that may affect the LA size or function. They were all subjected to history taking, clinical examination and echocardiographic study with assessment of LA functions [total LA stroke volume, LA expansion index by conventional 2D echocardiography and Global peak atrial longitudinal strain by speckle tracking (PALS)], left ventricular (LV) systolic and diastolic functions, and LV mass.

Results

Different indices of LA dysfunction (Total LA stroke volume, LA expansion index and global PALS) were significantly lower in the hypertensive group despite the normal LA volume index in all the studied subjects. The presence of diabetes mellitus (DM) and higher grade of LV diastolic dysfunction were significantly associated with lower global PALS. The higher age, systolic blood pressure (BP), body mass index (BMI), LA volume index, and LV mass index and the lower LA expansion index were associated with lower global PALS.

Conclusion

Speckle tracking echocardiography is a useful novel technique in detecting LA dysfunction in hypertension even before LA enlargement occurs.

The mitral annular displacement by two-dimensional speckle tracking: a new tool in evaluating the left atrial function

BACKGROUND

The methods used to characterize the volume change and the deformation of the left atrium are highly dependent on technical factors and difficult to use in a clinical environment. The aim of this study was to demonstrate that mitral annular displacement by speckle tracking can be an alternative method to studying the longitudinal left atrial function.

METHODS

Ninety study participants (54% men), with a mean age of 53(±15) years, underwent a complete echocardiographic examination, comprising two-dimensional, three-dimensional and tissue Doppler imaging (TDI). They were divided into normal individuals (35) and patients having an abnormal echocardiography (55).

RESULTS

There was a very strong correlation between three-dimensional volumetric function and mitral annular displacement, both for the reservoir (r = 0.78; P < 0.0001) and contractile (r = 0.76; P < 0.0001) functions. The correlation with the longitudinal strain displayed an r = 0.87, P > 0.0001 for the reservoir and r = 0.81, P < 0.0001 for the contractile function. The systolic speed in pulsed TDI and the systolic displacement had an r = 0.83, P < 0.0001. Mitral annular displacement was a very good discriminator for normal versus abnormal participants [area under the curve (AUC) for reservoir = 0.872 and for contractile = 0.843; P < 0.0001], performing less well than three-dimensional (AUC reservoir = 0.892 and contractile = 0.915; P < 0.0001) or deformation (AUC = 0.921 and 0.903 respectively; P < 0.0001), but better than pulsed TDI (AUC = 0.807; P < 0.0001). The percentage error was ±15% for interobserver and ±12% for intraobserver variability. The time taken for displacement analysis was 9 ± 3 s for an experienced cardiologist and 12 ± 4 s for a beginner.

CONCLUSION

Mitral annular displacement by speckle tracking is a reliable and fast method to evaluate left atrial function. Given the strength of the correlations with strain parameters, it could be used as a surrogate measure of the deformation of left atrium.

Evaluating functional capacity, and mortality effects in the presence of atrial electromechanical conduction delay in patients with systolic heart failure

Objective:

Atrial functions are relatively suppressed in heart failure (HF). We aimed to investigate the associations of intra- and inter-atrial electromechanical conduction delay (EMCD) with functional class and mortality over a 12-month follow-up period.

Methods:

The prospective study included 65 patients with systolic HF and 65 healthy subjects with normal sinus rhythm. Left ventricular (LV) systolic functions and left atrial (LA) dimensions and volumes were evaluated by transthoracic echocardiography. Tissue Doppler imaging (TDI) signals at the lateral border of the mitral annulus (lateral PA’), septal mitral annulus (septal PA’), and tricuspid annulus (tricuspid PA’) were measured. Intra- and inter-atrial EMCD were calculated.

Results:

Mitral inflow velocities were studied using pulsed-wave Doppler after placing the sample volume at the leaflets’ tips. The peak early (E wave) and late (A wave) velocities were measured. The septal annular E/E’ ratio was relatively higher and lateral, septal, and right ventricular S, E’, and A’ waves were significantly lower in the HF group than in the control group (12.49±6.03 – 7.16±1.75, pE/E’ <0.0001). Intra-atrial EMCD was detected as 117.5 ms and inter-atrial EMCD as 127.5 ms in patients with prolonged atrial EMCD. A significant increase was found in prolonged intra- and inter-atrial EMCD according to functional capacity increase (p=0.012 and p=0.031, respectively). The incidence of mortality was significantly higher in patients with prolonged atrial EMCD (p=0.025), and 5 patients in the HF group died during the study over the 12-month follow-up period.

Conclusions:

In this study, we found a relationship between prolonged atrial conduction time and increased functional class and mortality in patients with systolic HF. (Anatol J Cardiol 2016; 16: 579-86)

Quantitative description of the 3D regional mechanics of the left atrium using cardiac magnetic resonance imaging

The left atrium (LA) plays an important role in the maintenance of hemodynamic and electrical stability of the heart. One of the conditions altering the atrial mechanical function is atrial fibrillation (AF), leading to an increased thromboembolic risk due to impaired mechanical function. Preserving the regions of the LA that contribute the greatest to atrial mechanical function during curative strategies for AF is important. The purpose of this study is to introduce a novel method of regional assessment of mechanical function of the LA. We used cardiac MRI to reconstruct the 3D geometry of the LA in nine control and nine patients with paroxysmal atrial fibrillation (PAF). Regional mechanical function of the LA in pre-defined segments of the atrium was calculated using regional ejection fraction and wall velocity. We found significantly greater mechanical function in anterior, septal and lateral segments as opposed to roof and posterior segments, as well as a significant decrease of mechanical function in the PAF group. We suggest that in order to minimize the impact of the AF treatment on global atrial mechanical function, damage related to therapeutic intervention, such as catheter ablation, in those areas should be minimized.

Early detection of left atrial strain abnormalities by speckle-tracking in hypertensive and diabetic patients with normal left atrial size

BACKGROUND

Systemic hypertension and type 2 diabetes mellitus are associated with impaired left atrial (LA) function, but whether LA functional abnormalities also occur in patients with hypertension and diabetes who have normal LA sizes is unknown. The aim of this study was to explore LA strain using speckle-tracking echocardiography in patients with hypertension or diabetes and normal LA size.

METHODS

LA strain was studied by speckle-tracking echocardiography in 155 patients with hypertension or diabetes with LA volume indexes < 28 mL/m(2) (83 with hypertension, 34 with diabetes, and 38 with both diabetes and hypertension) and 36 age-matched controls. The following indexes were measured: peak atrial longitudinal strain, time to peak atrial longitudinal strain, atrial longitudinal strain during early diastole and late diastole, and peak LA strain rate during ventricular systole, early diastole, and late diastole.

RESULTS

Peak atrial longitudinal strain was lower in patients with hypertension (29.0 ± 6.5%) and those with diabetes (24.7 ± 6.4%) than in controls (39.6 ± 7.8%) and further reduced in patients with diabetes and hypertension (18.3 ± 5.0%) (P < .0001). Similar results were found for atrial longitudinal strain during early diastole, atrial longitudinal strain during late diastole, and peak LA strain rate during ventricular systole and early diastole (P < .0001 for all). An inverse trend was found for time to peak atrial longitudinal strain, whereas no differences in peak LA strain rate during late diastole were observed. Two-way analysis of variance showed no interactions between hypertension and diabetes. In multivariate analyses, hypertension and diabetes were both independently associated with decreases in all LA strain and strain rate indexes, with the exception of peak LA strain rate during late diastole.

CONCLUSIONS

LA deformation mechanics are impaired in patients with hypertension or diabetes with normal LA size. The coexistence of both conditions further impairs LA performance in an additive fashion. Speckle-tracking echocardiography may be considered a promising tool for the early detection of LA strain abnormalities in these patients.

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.

Managing catheter ablation for atrial fibrillation: the role of echocardiography

Atrial fibrillation (AF) is a common arrhythmia associated with the serious clinical consequences of systemic thrombo-embolism and heart failure. Catheter ablation for AF is an evolving treatment option for patients with drug-refractory paroxysmal and persistent AF. The ablation procedure relies on precise knowledge of the left atrium, left atrial appendage, and pulmonary venous anatomy and function. Echocardiography is an integral component of multiple imaging modalities which contribute to its success. Both transoesophageal echocardiography and transthoracic echocardiography provide essential anatomical and functional information to guide all aspects of management. This article reviews the role of echocardigraphy in AF ablation, from appropriate patient selection and pre-procedural screening, to evaluating complications and determining the need for long-term anticoagulation.

Comparison of left atrial volumes and function by real-time three-dimensional echocardiography in patients having catheter ablation for atrial fibrillation with persistence of sinus rhythm versus recurrent atrial fibrillation three months later

Real-time 3-dimensional echocardiography (RT3DE) can provide a unique combination of accurate left atrial (LA) volume quantification and rapid, automatic assessment of LA function. The aim of the study was to evaluate the changes in LA volumes and function in patients with atrial fibrillation (AF) undergoing radiofrequency catheter ablation (RFCA) using RT3DE; 57 consecutive patients referred for RFCA were studied. Paroxysmal AF was present in 43 patients (75%) and persistent AF in 14 (25%). After a mean follow-up of 7.9 +/- 2.7 months, patients were divided into 2 groups: successful RFCA (SR group) and recurrence of AF (AF group). RT3DE was performed before, within 3 days, and 3 months after RFCA to assess LA volumes (maximum, minimum, and preA) and LA functions (passive, active, and reservoir). A total of 38 patients (67%) had successful RFCA (SR group). Immediately after RFCA, no significant changes in LA volumes and function were observed. After 3 months, a significant reduction in LA volumes (maximum: 26 +/- 8 to 23 +/- 7 ml/m(2), p <0.01) was noted only in the SR group, with a significant improvement in LA active (22 +/- 8% to 33 +/- 9%, p <0.01) and reservoir functions (116 +/- 45% to 152 +/- 54%, p <0.01). Conversely, the AF group showed a trend towards a deterioration of LA volumes and function. In conclusion, in patients who maintain sinus rhythm after RFCA, a significant reverse remodeling and functional improvement of the left atrium is observed using RT3DE.