Pre-operative left atrial strain predicts post-operative atrial fibrillation in patients undergoing aortic valve replacement for aortic stenosis

Post-operative atrial fibrillation (AF) is a common and serious complication in patients undergoing aortic valve replacement (AVR). Speckle tracking echocardiography (STE) has recently enabled the quantification of longitudinal myocardial left atrial (LA) deformation dynamics. Our aim was to investigate LA preoperative mechanical function in patients undergoing AVR for aortic stenosis using STE and determine predictors of post-operative AF. 76 patients with aortic stenosis in sinus rhythm, undergoing AVR, were prospectively enrolled. Conventional echocardiographic parameters, and peak atrial longitudinal strain (PALS) were measured in all subjects the day before surgery. PALS values were obtained by averaging all segments in the 4- and 2-chamber views (global PALS). All patients received biological valve prostheses and a standard postoperative care. Postoperative AF occurred in 15 patients (19.7 %). On univariate analysis among all clinical and echocardiographic variables, global PALS showed the highest diagnostic accuracy (HR 6.55 p < 0.0001; AUC of 0.89) with a cut-off value <16.9 %, having sensitivity and specificity of 86 and 91 %, respectively, in predicting postoperative AF. LA volume indexed and E/e’ ratio had lower diagnostic accuracy (AUC 0.76 and 0.51, respectively). On multivariate analysis global PALS remains a significant predictor of postoperative AF (p < 0.0001). STE analysis of LA myocardial deformation is considered a promising tool for the evaluation of LA subclinical dysfunction in patients undergoing AVR, giving a potentially better risk stratification for the occurrence of postoperative AF.     

Left atrial volume computed by 3D rotational angiography best predicts atrial fibrillation recurrence after circumferential pulmonary vein isolation

Left atrium (LA) size is a well-studied predictor of atrial fibrillation (AF) recurrence after pulmonary vein isolation (PVI). Yet, there is still little agreement on the best imaging technique to size the LA, and on the most appropriate sizing parameter. Volumetric assessment of LA with three-dimensional rotational angiography (3DRA LA volume index) might be a valid alternative to the commonly used transthoracic echocardiography (TTE LA volume index). The aim of our study was to investigate whether LA volume by 3DRA at the time of PVI is able to predict the risk of atrial fibrillation recurrence. We analysed 352 consecutive patients with symptomatic paroxysmal or persistent atrial fibrillation referred for PVI to our Institution. In all patients, LA volume index (LAVI) was assessed by TTE and by 3DRA. Sinus rhythm was restored after PVI in 348 patients (99%). Average TTE-LAVI and 3DRA-LAVI were 37?±?12 and 83?±?18 ml/m2, respectively. At a median follow-up of 19 (12, 24) months, 27% of patients had AF recurrence after the first PVI. At the univariate analysis, persistent AF (p?<?0.01), use of anti-arrhythmic drugs (AAD) (p?<?0.05) and 3DRA-LAVI (p?<?0.01) were significantly associated with AF recurrence. In contrast, none of the echocardiographic parameters considered, including TTE-LAVI, was associated with AF recurrence (p?=?0.29). At the multivariate analysis, 3DRA-LAVI was the only independent predictor for AF recurrence (HR 1.01 [1.00–1.03], p?=?0.017). Left atrial volume measured with 3DRA is superior to TTE assessment and to AF history in predicting atrial fibrillation recurrence after PVI.     

Aortic stiffness is related to left ventricular diastolic function in patients with diabetes mellitus type 1: assessment with MRI and speckle tracking strain analysis

Diabetes mellitus type 1 (DM1) is associated with aortic stiffening and left ventricular (LV) diastolic dysfunction, however the relationship between aortic stiffness and LV diastolic dysfunction in DM1 patients is still largely unknown. The purpose of this study was to evaluate whether an increased aortic stiffness, expressed by increased aortic pulse wave velocity (PWV), is associated with subclinical LV diastolic dysfunction and decreased left atrial (LA) compliance as assessed with speckle tracking strain analysis in patients with DM1. Aortic PWV was assessed with cardiovascular magnetic resonance in 41 DM1 patients. Patients underwent echocardiography for assessment of conventional LV diastolic function indices and LV and LA longitudinal strain and strain rate (SR) assessed with speckle tracking strain analysis. LV SR during the isovolumic relaxation period (SRIVR) and LA strain were recorded and the E-wave velocity to SRIVR velocity ratio (E/SRIVR) was calculated. Independent samples t test and multivariate linear regression analyses were used for statistical analyses. Aortic PWV significantly correlated with SRIVR (β = ?0.71, p < 0.001), E/SRIVR (β = 0.61, p = 0.002) and LA strain (β = ?0.47, p = 0.014), but not with conventional echocardiographic markers of diastolic function (all p > 0.10). In DM1 patients, aortic stiffness is inversely associated with sensitive markers of LV diastolic function and decrease in LA compliance as measured with echocardiographic speckle tracking strain analysis.     

Assessment of left and right atrial 3D hemodynamics in patients with atrial fibrillation: a 4D flow MRI study

Atrial fibrillation (AF) is associated with embolic stroke due to thrombus formation in the left atrium (LA). Based on the relationship of atrial stasis to thromboembolism and the marked disparity in pulmonary versus systemic thromboembolism in AF, we tested the hypothesis that flow velocity distributions in the left (LA) versus right atrium (RA) in patients with would demonstrate increased stasis. Whole heart 4D flow MRI was performed in 62 AF patients (n = 33 in sinus rhythm during imaging, n = 29 with persistent AF) and 8 controls for the assessment of in vivo atrial 3D blood flow. 3D segmentation of the LA and RA geometry and normalized velocity histograms assessed atrial velocity distribution and stasis (% of atrial velocities <0.2 m/s). Atrial hemodynamics were similar for RA and LA and significantly correlated (mean velocity: r = 0.64; stasis: r = 0.55, p < 0.001). RA and LA mean and median velocities were lower in AF patients by 15–33 % and stasis was elevated by 11–19 % compared to controls. There was high inter-individual variability in LA/RA mean velocity ratio (range 0.5–1.8) and LA/RA stasis ratio (range 0.7–1.7). Patients with a history of AF and in sinus rhythm showed most pronounced differences in atrial flow (reduced mean velocities, higher stasis in the LA). While there is no systematic difference in LA versus RA flow velocity profiles, high variability was noted. Further delineation of patient specific factors and/or regional atrial effects on the LA and RA flow velocity profiles, as well as other factors such as differences in procoagulant factors, may explain the more prevalent systemic versus pulmonary thromboembolism in patients with AF.     

Increased pericardial adipose tissue is correlated with atrial fibrillation and left atrial dilatation

Introduction

Pericardial adipose tissue (PAT), a visceral fat depot surrounding the heart, serves as an endocrine active organ and is associated with inflammation. There is growing evidence that atrial fibrillation (AF) is linked with inflammation, which in turn can be a promoter of left atrial remodeling. The aim of this study was to evaluate a potential correlation of PAT to AF and left atrial structural remodeling represented by LA size.

Methods

PAT was measured in 1,288 patients who underwent coronary artery calcium-scanning for coronary risk stratification. LA size was determined by two independent readers. Patients were subdivided into patients without AF, patients with paroxysmal and persistent AF.

Results

PAT was independently correlated with AF, persistent AF, and LA size (all p values <0.001). No association could be observed between paroxysmal AF and PAT. These associations persisted after multivariate adjustment for AF risk factors such as age, hypertension, valvular disease, heart failure, and body mass index (AF: OR 1.52, 95 % CI 1.15–2.00, p = 0.003; persistent AF: OR 2.58, 95 % CI 1.69–3.99, p = 0.001; LA size: regression coefficient 0.15 with 95 % CI 0.10–0.20, p < 0.001).

Conclusion

PAT is associated with AF, in particular with persistent AF and LA size. These findings suggest that PAT could be an independent risk factor for the development of AF and for LA remodeling.     

Speckle tracking echocardiography derived 2-dimensional myocardial strain predicts left ventricular function and mass regression in aortic stenosis patients undergoing aortic valve replacement

Regression of left ventricular (LV) mass in severe aortic stenosis (AS) following aortic valve replacement (AVR) reduces the potential risk of sudden death and congestive heart failure associated with LV hypertrophy. We investigated whether abnormalities of resting LV deformation in severe AS can predict the lack of regression of LV mass following AVR. Two-dimensional speckle tracking echocardiography (STE) was performed in a total of 100 subjects including 60 consecutive patients with severe AS having normal LV ejection fraction (EF > 50 %) and 40 controls. STE was performed preoperatively and at 4 months following AVR, including longitudinal strain assessed from the apical 4-chamber and 2-chamber views and the circumferential and rotational mechanics measured from the apical short axis view. In comparison with controls, the patients with AS showed a significantly lower LV longitudinal (p < 0.001) and circumferential strain (p < 0.05) and higher apical rotation (p < 0.001). Following AVR, a significant improvement was seen in both strains (p < 0.001 for each respectively), however, apical rotation remained unchanged (p = 0.14). On multivariate analysis, baseline LV mass (odds ratio 1.02; p = 0.011), left atrial volume (odds ratio 0.81; p = 0.048) and circumferential strain (odds ratio 0.84; p = 0.02) independently predicted LV mass regression (>10 %) following AVR. In conclusion, STE can quantify the burden of myocardial dysfunction in patients with severe AS despite the presence of normal LV ejection fraction. Furthermore, resting abnormalities in circumferential strain at LV apex is related with a hemodynamic milieu associated with the lack of LV mass regression during short-term follow up after AVR.     

Left atrial functional reservoir: predictive value for outcome of catheter ablation in paroxysmal atrial fibrillation

Left arial (LA) function, defined according to conduit, reservoir and booster functions, is closely linked to left ventricular (LV) mechanics, particularly during diastole. Right ventricular pacing (RVP) is thought to impair LA diastolic restoring forces through alteration of ventricular activation. The aim of this study was to determine whether the LA functional reservoir estimated as the change in mean LA ejection fraction (EF) immediately after RVP, and for the second and for the third beats after RVP, predicts clinical outcome in patients with paroxysmal atrial fibrillation (AF) who have undergone catheter ablation (CA). Data from 155 patients with paroxysmal AF (56.0 ± 10.6 years, M:F = 114:41) were analyzed. All patients underwent LA angiography during RVP. LA EFs were measured at the immediate first (LA EF₁), second (LA EF₂) and third beats (LA EF₃) after RVP, using a right anterior oblique 30° view. During follow-up, AF recurred in 35 patients (22.6 %). Mean LA EF₁ was 37.9 ± .8 % in the AF recurrence group and 48.0 ± 8.6 % in the non-recurrence group (P < 0.001). Mean LA EF₂ and LA EF₃ were also lower in the AF recurrence group than in the non-recurrence group (P < 0.001, respectively). Mean percent changes from LA EF₂ to LA EF₃ were ?0.4 ± 3.4 in the AF recurrence group and 5.2 ± 4.9 in the non-recurrence group (P = 0.041). The change in mean EF from LA EF₁ to LA EF₃ in the non-recurrence group was significantly greater than in the recurrence group (P = 0.001). Cox regression analysis showed that predictors of AF recurrence were LA EF₂, LA EF₃ and accompanied obstructive sleep apnea (OSA) (P < 0.001, respectively). Decreased functional LA reservoir (LA EF after RVP) and OSA are significantly related to recurrence of AF following CA in patients with paroxysmal AF.     

CMR findings in patients with hypertrophic cardiomyopathy and atrial fibrillation

Objectives

We sought to evaluate the relation between atrial fibrillation (AF) and the extent of myocardial scarring together with left ventricular (LV) and atrial parameters assessed by late gadolinium-enhancement (LGE) cardiovascular magnetic resonance (CMR) in patients with hypertrophic cardiomyopathy (HCM).

Background

AF is the most common arrhythmia in HCM. Myocardial scarring is also identified frequently in HCM. However, the impact of myocardial scarring assessed by LGE CMR on the presence of AF has not been evaluated yet.

Methods

87 HCM patients underwent LGE CMR, echocardiography and regular ECG recordings. LV function, volumes, myocardial thickness, left atrial (LA) volume and the extent of LGE, were assessed using CMR and correlated to AF. Additionally, the presence of diastolic dysfunction and mitral regurgitation were obtained by echocardiography and also correlated to AF.

Results

Episodes of AF were documented in 37 patients (42%). Indexed LV volumes and mass were comparable between HCM patients with and without AF. However, indexed LA volume was significantly higher in HCM patients with AF than in HCM patients without AF (68 ± 24 ml·m^-2 versus 46 ± 18 ml·m^-2, p = 0.0002, respectively). The mean extent of LGE was higher in HCM patients with AF than those without AF (12.4 ± 14.5% versus 6.0 ± 8.6%, p = 0.02). When adjusting for age, gender and LV mass, LGE and indexed LA volume significantly correlated to AF (r = 0.34, p = 0.02 and r = 0.42, p < 0.001 respectively). By echocardiographic examination, LV diastolic dysfunction was evident in 35 (40%) patients. Mitral regurgitation greater than II was observed in 12 patients (14%). Multivariate analysis demonstrated that LA volume and presence of diastolic dysfunction were the only independent determinant of AF in HCM patients (p = 0.006, p = 0.01 respectively). Receiver operating characteristic curve analysis indicated good predictive performance of LA volume and LGE (AUC = 0.74 and 0.64 respectively) with respect to AF.

Conclusion

HCM patients with AF display significantly more LGE than HCM patients without AF. However, the extent of LGE is inferior to the LA size for predicting AF prevalence. LA dilation is the strongest determinant of AF in HCM patients, and is related to the extent of LGE in the LV, irrespective of LV mass.     

Left atrial remodelling in patients undergoing transcatheter aortic valve implantation: a speckle-tracking prospective, longitudinal study

Aortic stenosis (AS) results in several left ventricular (LV) disturbances as well as progressive left atrial (LA) enlargement and dysfunction. Transcatheter aortic valve implantation (TAVI) reverses LV remodelling and improves overall systolic function but its effect on LA function remains undetermined. The aim of this prospective, longitudinal study was to investigate the effects of TAVI on LA structure and function. We studied thirty-two patients with severe symptomatic AS who underwent TAVI, using standard and 2-dimensional speckle-tracking echocardiography before, at 40-day and at 3-month follow-up. Following TAVI, mean transvalvular gradient decreased (p < 0.001). Both LA area index and LA volume index decreased at 40-day follow-up (16.2 ± 6.4 vs. 12.5 ± 2.9 cm²/m², and 47.3 ± 12.0 vs. 42.8 ± 12.5 mL/m², respectively, p < 0.05) and values remained unchanged at 3 months. The reduction of LA size was accompanied by a significant increase in global peak atrial longitudinal strain (14.4 ± 3.9 vs. 19.1 ± 4.7 %, p < 0.001) and in global peak atrial contraction strain (8.4 ± 2.5 vs. 11.0 ± 4.1 %, p < 0.05) at 3-month follow-up. LA stiffness measurements significantly decreased 3 months after TAVI (0.93 ± 0.59 vs. 0.65 ± 0.37, respectively, p < 0.001). Trans-aortic mean gradient change and pre-procedural LA volume were identified as predictors of global peak atrial longitudinal strain increase (β = ?0.41, β = ?0.35, respectively, p < 0.0001) while pre-procedural LA volume and trans-aortic mean gradient change as predictor of LA volume index reduction 3 months after TAVI (β = ?0.37, β = ?0.28, respectively, p < 0.0001). TAVI is associated with significant recovery of LA structure and function suggesting a reverse cavity remodelling. Such functional recovery is primarily determined by the severity of pre-procedural valve stenosis.     

Left atrial expansion index is an independent predictor of diastolic dysfunction in patients with preserved left ventricular systolic function: a three dimensional echocardiography study

In the absence of mitral valve disease left atrial (LA) volume is a marker of diastolic dysfunction and its severity. This study investigated the relationship between left ventricular (LV) end diastolic pressure (LVEDP) and LA volumes and phasic atrial functions detected by real-time full volume three-dimensional echocardiography (RT3DE), in a patient population with preserved LV systolic function. Seventy-two (39 female and 33 male; mean age 56.1 ± 9.0 years) stable patients with normal LV ejection fraction (EF) undergoing cardiac catheterization were studied. All patients underwent comprehensive echocardiographic examination just before catheterization and LVEDP was obtained. In addition to conventional echocardiographic measurements and Doppler indices; by using RT3DE LA maximum, minimum and pre-a-wave volumes were measured; LA total, passive and active emptying volumes and fractions were calculated. LV systolic function was assessed by EF and global longitudinal strain by speckle tracking. RT3DE minimum LA volume index, RT3DE active LAEF and LA expansion index (EI) were statistically significant univariate predictors of LVEDP ≥ 16 mmHg. When age and hypertension adjusted multivariate analysis was performed EI [β = ?1.741, p = 0.015; OR 0.175; 95 % CI (0.043–0.717)] was an independent predictor of elevated LVEDP. RT3DE evaluation of LA function during entire cardiac cycle has incremental value for the diagnosis of diastolic dysfunction in patients with preserved EF. We suggest that RT3DE evaluation of LA may find clinical application in this field.     

Relationship between left atrial appendage emptying and left atrial function using cardiac magnetic resonance in patients with atrial fibrillation: comparison with transesophageal echocardiography

To compare cardiac magnetic resonance (CMR) quantifications of left atrium (LA) function and left atrial appendage (LAA) emptying depending on the presence of LA spontaneous echogenic contrast (LA-SEC) on transesophageal echocardiography (TEE) in patients with atrial fibrillation (AF). A total of 48 patients with AF underwent sequential CMR examination and TEE in preparation for catheter ablation. The CMR protocol included cine and velocity encoding (VENC) sequences for evaluation of both LA function and LAA emptying. The peak blood velocity of LAA just before left ventricle systole was defined as the LAA emptying velocity (LAA-EV). Depending on the presence of LA-SEC on TEE, patients were divided into two groups, the SEC group (n?=?15) and the non-SEC group (n?=?33). Mean LAA-EV was significantly greater in the non-SEC group than in the SEC group (54.5?±?24.8 ml/s vs. 26.0?±?22.6 ml/s, P?<?0.01). LAA-EV had a significant positive relationship (P?<?0.05) with LAA backflow velocity, as assessed using TEE. Use of an optimal LAA-EV cutoff value of 35 ml/s to predict LA-SEC yielded a sensitivity of 80.0?%, a specificity of 75.7?%, and positive and negative predictive values of 58.8 and 83.9?%, respectively. Using VENC-CMR, LAA-EV is associated with LA function and can be useful for predicting LA-SEC in patients with AF.     

Left atrial deformation as a potent predictor for paroxysmal atrial fibrillation in patients with end-stage renal disease

It is widely known that various factors contribute to left atrial (LA) mechanical dysfunction in patients with end stage renal disease (ESRD). However, the connection between atrial dysfunction and arrhythmic events such as paroxysmal atrial fibrillation (PAF), in this group of patients, remains unclear. The purpose of our study was to evaluate prospectively the association between LA deformation indices and PAF in ESRD patients. 79 patients (41 men, mean age 57?±?17) with ESRD and preserved left ventricular systolic function comprised the study population. All patients underwent a baseline comprehensive echocardiography study and were followed for a mean period of 16?±?5 months. PAF episodes, first and the following events, were reported. LA longitudinal strain reflecting LA reservoir function and LA longitudinal strain rate reflecting LA pump function were specifically evaluated as LA deformation indices of interest, using 2D speckle tracking echocardiography. At the end of follow up period nine patients died. 15 of the rest 70 reported one or more episodes of PAF. LA indexed volumes were significantly higher in patients with PAF (32?±?26 vs. 21.5?±?9 ml/m², p?=?0.002), mean LA strain was significantly reduced (17?±?7 vs. 27?±?9%, p?<?0.001) as well as mean LA stain rate (??1.19?±?0.5 vs. ??1.95?±?0.5 1/s, p?<?0.001). Multivariate analysis showed that LA strain rate when adjusted with age together with PAF history remained the single most significant echocardiographic parameter for PAF prediction. Impaired LA strain and LA strain rate are associated with PAF in ESRD patients. LA strain rate might be a better independent predictor of PAF, compared to standard echocardiographic indices. Further prospective studies are needed to validate its relevance in routine clinical practice.     

Left atrial appendage: morphology and function in patients with paroxysmal and persistent atrial fibrillation

The anatomical and functional characteristics of the left atrial appendage (LAA) and its relationships with anatomical remodeling and ischemic stroke in patients with atrial fibrillation (AF) have not been clearly established. The purpose of this study was to determine whether functional and morphological features of the LAA independently predict clinical outcome and stroke in patients with AF who underwent catheter ablation (CA). Two hundred sixty-four patients with AF, including 176 with paroxysmal AF (PAF, 54.0 ± 11.4 years old, M:F = 138:38) and 88 with persistent AF (PeAF, 56.4 ± 9.6 years old, M:F = 74:14) were studied. Of these patients, 31 (11.7 %) had a history of stroke/TIA (transient ischemic attack). The LA and LAA volumes were 124.0 ± 42.4 and 24.9 ± 4.3 ml in PeAF, these values were greater than those in PAF (81.2 ± 24.8 ml and 21.2 ± 5.1 ml, P < 0.001). The AF type (P = 0.016) and AF duration (P = 0.005), and anti-arrhythmic drugs use (P < 0.001) were significant predictors of AF recurrence after CA in all patients. Compared with patients without history of stroke, stroke patients had larger LA volume (106.9 ± 23.0 vs. 94.0 ± 38.9 ml, P = 0.004) and had lower LAA EF (50.0 ± 11.0 vs. 65.7 ± 13.4 %, P < 0.001). The independent predictors of stroke were age (P = 0.002) and LAA EF (P < 0.001) in PAF patients and that was only age (P = 0.001) in PeAF patients. In anatomical and morphological parameters of the LA and LAA, only depressed systolic function of the LAA was significantly related to stroke/TIA and recurrence of AF after CA in paroxysmal AF patients. Further large scaled prospective study is required for validation.     

The impact of atrial fibrillation ablation on left atrial function: association with baseline left atrial function

Background: The effect of atrial fibrillation (AF) ablation on left atrial (LA) function has not been sufficiently determined. Methods: We enrolled 115 consecutive patients with paroxysmal or persistent AF that underwent AF ablation. Multidetector computed tomography was performed in sinus rhythm before and 3 months after ablation to evaluate LA volume (LAV) and function. Estimates of maximum and minimum LAV were used to calculate LA emptying fraction (LAEF) ([maximum–minimum LAV]/maximum LAV × 100). Results: AF ablation significantly decreased maximum LAV (59.0 ± 20.4 to 53.3 ± 16.7 cm³, P = 0.001), and maintained LAEF (44.5 ± 13.1% to 43.7 ± 10.9%, P = 0.49). The larger the baseline maximum LAV, the greater the decrease in LAV after ablation, and a smaller baseline LAEF was associated with a larger recovery of LAEF after ablation (regression coefficient =−0.45 and −0.56, respectively, P < 0.0001). Multivariable analyses revealed that an impaired baseline LAEF was an independent predictor of an improvement in LA function (an increase in LAEF of >10%; odds ratio [OR] = 0.88, P < 0.0001), while an older age and preserved baseline LAEF were independently associated with a deterioration of LA function (a decrease in LAEF of >10%; OR = 1.06, P = 0.03; and OR = 1.10, P = 0.0001). Conclusions: AF ablation appears to have a beneficial effect on LA function in patients with impaired LA function at baseline. However, it may reduce LA function in patients with an older age and preserved baseline LAEF. (PACE 2011;1–8)     

Relevance of transthoracic left atrial appendage wall velocity measurement in addition to left atrial volume for noninvasive and quantitative assessment of left atrial thrombogenesis in patients with atrial fibrillation and normal D-dimer levels

Purpose

This study examined the role of left atrial (LA) appendage wall velocity (LAAWV) measurement in addition to LA size for the noninvasive assessment of thrombogenesis in patients with atrial fibrillation (AF) and normal plasma D-dimer levels.

Methods

In 58 non-valvular AF patients, LAAWV and the LA volume index (LAVI) were determined by transthoracic echocardiography. LA appendage flow velocity and severity of spontaneous echo contrast (SEC) were determined by transesophageal echocardiography.

Results

LAAWV was strongly correlated with LA appendage flow velocity (r = 0.82), and LAVI was weakly correlated with LA appendage flow velocity (r = ?0.37). As SEC severity increased, LAAWV decreased (p < 0.001) and LAVI increased (p < 0.001). Among 52 patients with normal D-dimer levels, LAAWV < 10 cm/s had 71 % sensitivity and 94 % specificity for diagnosing severe SEC. Severe SEC was not found in 18/32 large LAVI patients (>34 mL/m²), but 17 of the 18 patients (94 %) had LAAWV < 10 cm/s. Severe SEC was found in 3/20 patients with normal LAVI, but all of them showed LAAWV < 10 cm/s.

Conclusion

The noninvasive measurement of transthoracic LAAWV in addition to LA volume is clinically relevant for quantitatively assessing thrombogenesis in AF patients with normal D-dimer levels.

     

Left atrial strain after maximal exercise in competitive waterpolo players

Left atrial (LA) function is a determinant of left ventricular (LV) filling. It carries out three main functions: reservoir, conduit, contractile. Aim of this study was to evaluate the role of LA and its deformation properties on LV filling at rest (R) and immediately after a maximal exercise (ME) through the speckle tracking echocardiography. Population enrolled was composed by 23 water polo athletes who performed a ME of six repeats of 100 m freestyle swim sets. At ME peak atrial longitudinal strain was reduced but all strain rate (SR) parameters increased, respectively positive peak SR at reservoir phase, SR negative peak at rapid ventricular filling (SRep) and SR negative peak at late ventricular filling (SRlp), that corresponds to atrial contraction phase. We showed a parallel increase in E and A pulsed Doppler wave and SRep and SRlp; particularly at ME, A wave and SRlp increased more respectively than E wave and SRep. SRlp was related to ejection fraction (EF) (r = ?0.47; p < 0.01). At multivariate analysis SRlp was an independent predictor of EF (β: ?0.47; p = 0.016). The increased sympathetic tone results into increased late diastolic LV filling with augmented atrial contractility and a decrease in diastolic filling time. During exercise LV filling was probably optimized by an enhanced and rapid LA conduit phase and by a vigorous atrial contraction during late LV filling.     

Effect of atrial fibrillation ablation on myocardial function: insights from cardiac magnetic resonance feature tracking analysis

Restoration of sinus rhythm may result in an improvement of left heart function in patients with atrial fibrillation (AF). Cardiovascular magnetic resonance (CMR) feature tracking (FT) technique may help detect subtle wall-motion abnormalities. Consequently this study aimed to analyse existence and reversibility of subclinical cardiac dysfunction following atrial fibrillation ablation. 28 consecutive patients (mean age 61 years) with paroxysmal AF underwent pulmonary vein isolation. CMR imaging was done 3 (±3) days before and 3.4 (±1.1) months after ablation. Left heart function was determined by performing FT analysis. Statistical analysis included paired student’s t test, random effects metaanalysis to assess the cohort’s health status and Bland–Altman analysis. 17 patients (61 %) were free from AF at follow-up. Bland–Altman analysis showed good coefficients of variation. Of all 195 parameters, 27 changed (14 %):9 improved significantly (5 %), 12 worsened significantly (6 %), whereas 6 parameters worsened not significantly (3 %). 18 of 120 systolic parameters changed (15 %), 14 worsened (12 %), 4 improved (3 %). In 9 of 75 diastolic parameters, values changed (12 %): 5 improved (7 %) and 4 worsened (5 %). Meta-analysis revealed that our collective’s FT values at baseline didn’t differ significantly from healthy volunteers’ values [Q values of 0.01 (p value 0.921) and 1.499 (p value 0.221)]. AF patients undergoing ablation appear to have near normal cardiac wall motion, which does not improve following successful ablation. Feature tracking analysis is a reliable tool to determine treatment effects but is more likely to show positive findings if the population is unhealthy.     

Pulmonary vein vestibule ablation for the control of atrial fibrillation in patients with impaired left ventricular function

INTRODUCTION: Congestive heart failure (CHF) and atrial fibrillation (AF) are frequently linked, and when associated produce additive deleterious effects. In this prospective study, the effects of catheter ablation for AF in patients with impaired left ventricular (LV) function are presented. METHODS: Baseline data and clinical outcome have been prospectively collected in 105 consecutive patients who underwent pulmonary vein ablation for the control of AF. We evaluated 40 patients affected by LV dysfunction with ejection fraction (EF)<40% and compared them to the remaining 65 patients with normal ventricular function in terms of changes in LV function, maintenance of sinus rhythm, and quality of life during follow-up. RESULTS: After a mean follow-up of 14+/-2 months, 87% of patients with impaired LV function and 92% of patients with normal ventricular function were in sinus rhythm, with or without antiarrhythmic therapy (P=NS). A significant improvement in LVEF and fractional shortening was documented in patients with CHF (33+/-2% vs 47+/-3%, and 19+/-4% vs 30+/-3%, P<0.01 for both comparisons). Evaluation of exercise capacity and quality of life documented better improvements in patients with CHF compared to patients without CHF. CONCLUSIONS: Catheter ablation in patients with LV dysfunction is feasible, not associated with higher procedural complications, and provides a significant improvement in LV performance, symptoms, and quality of life during follow-up.     

Double-contrast,single-phase computed tomography angiography for ruling out left atrial appendage thrombus prior to atrial fibrillation ablation

Prior to atrial fibrillation (AF) ablation, computed tomography angiography (CTA) is increasingly used for left atrial appendage (LAA) thrombus detection. LAA filling defects on CTA may represent thrombus or incomplete contrast mixing with blood. A pre-bolus of contrast material with delay before the CTA contrast bolus can help distinguish between thrombus and incomplete contrast mixing. We present results from a double-contrast, single-phase CTA protocol used in our daily clinical practice. In patients who underwent AF ablation between 2011 and 2015, double-contrast, single-phase CTA was performed prior to ablation. Two contrast boluses (30 and 70 ml) with 25-s interbolus delay were administered followed by prospectively triggered cardiac CTA. Only patients with left atrial (LA) or LAA filling defects underwent transesophageal echocardiography (TEE) to rule out thrombus. Prior to ablation, 605 CTA-scans were performed (median radiation dose: 3.1 mSv). In 579 CTA-scans (95.7?%), the LA and LAA completely filled with contrast. In 26 CTA-scans (4.3?%) the LAA showed a filling defect whereby thrombus could not be excluded. In 2 of those 26 patients (7.7?% and 0.3?% of the total population), TEE verified LAA thrombus. Low-risk LAA filling defects on CTA (n?=?7/26) with an inhomogeneous aspect, Houndsfield Unit values >100, and an indefinite border were all caused by incomplete contrast mixing. No thromboembolic complications occurred perioperatively or during 6 months follow-up. Prior to AF ablation, incidence of LAA filling defects on double-contrast, single-phase CTA is low. TEE remains warranted in all but low-risk filling defects to rule out thrombus.     

Acute conversion of persistent atrial fibrillation during dofetilide initiation

BACKGROUND: Dofetilide (D) is a highly selective blocker of the rapid component of the delayed rectifier potassium current and was approved for the treatment of atrial fibrillation (AF) based on a satisfactory safety/efficacy profile from trials in patients with left ventricle (LV) dysfunction or heart failure. The dose-dependant acute conversion rates (<72 hours) were reported to be in the range of 6-30%. We hypothesized that the acute pharmacological conversion rate of D is higher than previously reported if used in a healthier cohort of patients with persistent AF. METHODS AND RESULTS: Eighty consecutive patients received D dosing per Cockroft-Gault adjustment for creatinine clearance and QTc intervals. Patients were 61 +/- 10 years, 79% male, ejection fraction (EF) 53 +/- 13%, coronary artery disease 20%, and left atrial dimension 4.1 +/- 0.2 cms. The duration of the treated AF episode was a median of 19 days (range 10-113 days). All patients received D while on telemetry for at least six dosing intervals. After 2.2 +/- 1.2 doses, 77% of patients converted to sinus rhythm (SR) and 23% did not and required direct current (DC) cardioversion. Acute pharmacological conversion rates were: 20% for D 125 mcg bid, 44% for 250 mcg bid, and 85% for 500 mcg bid. None of the patients had torsade de pointes and none had to stop D for intolerance. Failure to convert to SR on D alone was associated with larger left atrium (LA) diameter (P = 0.04), longer duration of AF (P = 0.02), and use of lower dosages of D (P = 0.04). CONCLUSIONS: D had an unusually high pharmacological conversion rate, demonstrated an incremental dose response, and was well tolerated and safe, in a relatively healthy adult cohort with persistent AF. In addition to D dose, pharmaco-conversion was predicted by LA size and AF duration. D is a desirable alternative for conversion of AF in a variety of clinical settings.