Left Atrial Diastolic Function Research Articles

LEFT ATRIAL FIBROSIS IS ASSOCIATED WITH LEFT ATRIAL DIASTOLIC DYSFUNCTION MEASURED BY PRESSURE/VOLUME CURVES IN PATIENTS UNDERGOING ABLATION FOR ATRIAL FIBRILLATION

Atrial fibrillation (AF) is associated with left atrial (LA) systolic and diastolic dysfunction. LA diastolic functions are related with outcomes of catheter ablation for atrial fibrillation. This study is designed to correlate the diastolic functions measured by left atrial stiffness index (LASI)

Noninvasive assessment of left atrial fibrosis. Correlation between echocardiography, biomarkers, and electroanatomical mapping.

Left atrial (LA) fibrosis promotes atrial fibrillation (AF), may predict poor radiofrequency catheter ablation (RFCA) outcome, and may be assessed invasively using electroanatomical mapping (EAM). Speckle tracking echocardiography (STE) enables quantitative assessment of LA function. The aim was to assess the relationship between LA fibrosis derived from EAM and LA echocardiographic parameters as well as biomarkers of fibrosis in patients with AF. Sixty-six patients (64% males, mean age 56±10) with nonvalvular AF treated with first RFCA were prospectively studied. Seventy-three percent of patients were in sinus rhythm at the time of examination. LA geometry, systolic, and diastolic function were assessed. In STE global, peak atrial longitudinal (PALS) and contractile (PACS) strain were calculated. LA stiffness index (LAs) - the ratio of E/e' to PALS - was assessed. The EAM of LA was build using Carto System before RFCA. Low amplitude potentials area (LAPA) was quantitatively analyzed and expressed as a percentage of LA surface using the cut-off <0.5mV to detect potential sites of fibrosis. The serum concentrations of MMP-9, PIIINP, and TGFβ1were estimated before RFCA. Pearson correlation analysis showed a significant correlation between LA diastolic function parameters: PALS (-0.54, P<.001), LAs (0.65, P<.001), and LAPA in patients who were in sinus rhythm. Also LA volume significantly correlated with LAPA (0.44, P<.002). None of biomarkers correlated with LAPA. Left atrial diastolic parameters derived from STE correlate well with the extent of LA fibrosis. Thus, STE may be useful in the noninvasive assessment of LA fibrosis and selection of candidates for RFCA.

Left Atrial Diastolic Dysfunction And Pulmonary Venous Hypertension In Atrial Fibrillation: Clinical, Hemodynamic And Echocardiographic Characteristics.

Left ventricular diastolic dysfunction has been well described; diastolic abnormalities of the LA are less frequently recognized and poorly understood. The purpose of this study was to investigate the clinical, hemodynamic and echocardiographic features of left atrial (LA) diastolic dysfunction. Patients with atrial fibrillation (AF), severe LA enlargement, and pulmonary venous hypertension (PVH, Group 1) were compared to patients with pulmonary arterial hypertension (PAH), normal LA size and sinus rhythm (Group 2). All underwent right heart catheterization and transthoracic echo to evaluate hemodynamics and LA function. Mitral regurgitation was evaluated by transesophageal echocardiography. LA diastolic function was measured by comparing filling fraction, pulmonary venous flow and compliance. Right atrial, pulmonary artery systolic and mean pressures were similar. Mean wedge pressure were increased in Group 1, 20.8±2.6 versus 9.7±2.8 mm of Hg (p<0.0001). The most striking hemodynamic difference was large V wave in Group 1 without significant mitral regurgitation. LA filling fraction was abnormal in Group 1, 11.4%±8.5 compared to Group 2, 111.5%±44 (p<0.0001). LA compliance was 0.39±0.27 ml/m2/mmHg in Group 1 versus 6.8±4.54 ml/m2/mmHg in Group 2 (p=0.001). There was a strong negative correlation between the V wave and LA filling fraction (r= 0.756, p<0.001). The ratio of the height of the transmitral E wave divided by the S/D ratio (the LA diastolic dysfunction index) correlated very strongly with the V wave (r=0.907, p<0.001). LA diastolic dysfunction is present in some patients with long standing AF and PVH. LA diastolic dysfunction, in addition to left ventricular diastolic dysfunction, may contribute to the syndrome of heart failure with preserved left ventricular systolic function.

Abstract 19078: Pre-Existing Left Atrial Fibrosis and Diastolic Dysfunction is Associated With Deterioration in Diastolic Function Following Left Atrial Ablation In Patients With Recurrent Atrial Fibrillation

Background: Radiofrequency (RF) ablation for treatment of atrial fibrillation (AF) is known to induce left atrial (LA) fibrosis. LA diastolic dysfunction has been associated with AF and has shown predictive value for AF recurrence post ablation. This study is designed to evaluate the pattern of change in LA diastolic function following RF ablation. Methods: A total of 127 consecutive AF patients were enrolled in the AF Ablation MRI cohort. Fourteen underwent a repeat ablation for recurrent AF and were selected. During routine ablation procedure, LA pressures were acquired in sinus rhythm following trans-septal puncture and prior to ablation. LA diastolic function was evaluated by measuring the slope of the passive LA filling curve and was quantified using diastolic function scores defined by the ratio of change of LA pressure (as defined by invasive pressure measurements) to volume (as defined by MRI) during passive filling of LA (ΔP/ΔV) mmHg/ml and was measured prior to both ablations. The change in LA diastolic function was considered significant if &gt;25% change from baseline was observed. Percent left atrial fibrosis was quantified by using the image intensity ratio as previously described. Results: The mean diastolic function score for the 14 AF patients (62±7yrs, 79% male) was 0.76±0.28 mmHg/ml (Paroxysmal AF 0.58±0.18 and persistent AF 0.90±0.28, p=0.031). Of these, 4 (28.6%) patients had no substantial change &gt;25% in their diastolic function score (grp A) at repeat imaging. Six had improvement, 4 remained stable, grp B and 4 had deterioration-grp C. When compared with group A, group C had worse baseline LA diastolic function (0.6±0.2 v 1.1±0.3, p0.019) and greater baseline fibrosis (8.0±2.4% v 15.3±7.0, p0.042). Conclusion: Deterioration of diastolic function in patients with AF recurrence after LA ablation is associated with more extensive baseline fibrosis and worse baseline LA diastolic function.

Abstract 19158: MRI Based Non-Invasive Measures Correlates With Invasive Measurements of Left Atrial Diastolic Function in Atrial Fibrillation Patients

Background: Atrial fibrillation (AF) is associated with diminished cardiac functions. This study describes a novel methodology for non-invasive measurement of left atrial (LA) function in patients with AF. Methods: A total of 55 patients (81% male, 55% paroxysmal, 60.4±10.2 years) underwent cardiac MRI prior to AF ablation. Invasive LA pressure was measured during sinus rhythm following trans-septal puncture for AF ablation. LA pressure and volume (MRI derived) loops were prepared for all patients. LA diastolic function was defined as the ratio of the change in LA pressure to the change in LA volume during passive LA filling. Additionally, the ratio of pulmonary vein flow velocities during ventricular systole and diastole were obtained using phase contrast MRI (Figure top panel, S/D ratio). Patients with ventricular diastolic dysfunction (as seen by E/A ratio) were excluded. LA systolic functions were calculated from the active emptying fraction during atrial contraction. Diastolic dysfunction scores greater than the 90th %tile (&gt;1.6mmHg/ml) were considered to signify severe diastolic dysfunction. Results: The mean diastolic dysfunction score was 0.76±0.7 mmHg/ml. The score was higher in patients with persistent versus paroxysmal AF (1.0±0.9 vs. 0.60±0.5,p=0.02). The mean S/D ratio was 1.04±0.6; and was lower in patients with persistent versus paroxysmal AF (0.9±0.5 vs. 1.2±0.7, p=0.04). There was a negative linear association between diastolic dysfunction scores and S/D ratio measures (Figure bottom panel, p &lt;0.001). In a multivariate analysis adjusting for age, LA systolic function and CHADS2 score, the severe diastolic dysfunction was independently associated with lower S/D ratio (p-0.03). Conclusion: The non-invasive MRI derived ratio of pulmonary vein flow velocities during systole and diastole are associated with the MRI/invasive derived diastolic dysfunction score, and appear to be a fair surrogate of LA diastolic function.

Evolution of Left Atrial Systolic and Diastolic Functions in Different Stages of Hypertension: Distinct Effects of Blood Pressure Control

Background: To evaluate the left atrial (LA) volume, and LA systolic (contractile) and diastolic (expansion) functions in different stages of hypertension with or without atrial fibrillation (AF), as well as the effects of good blood pressure control. Methods: A prospective observational study. Individuals including 22 normotensive controls, 23 patients with mild hypertension, 20 with severe hypertension, and 17 with hypertension and paroxysmal AF were recruited for paired echocardiography studies at baseline and 6 months after control of hypertension. Results: With increasing severity of hypertension, left ventricular (LV) diastolic function deteriorated with decreasing LV septal E′/A′ and increasing E/E′ ratios. LA expansion index was reduced in parallel. LA expansion index was correlated positively with LV E′/A′ (r = 0.43, p = 0.022) and inversely with LV E/E′ (r = 0.49, p = 0.009). Significant improvement of LV diastolic function and LA expansion index preceded the reduction of LA volume after blood pressure control. In patients with paroxysmal AF, LA volume reduction was more evident in patients receiving angiotensin-converting enzyme inhibitors or angiotensin II type 1 receptor blockers. Conclusions: With progressive LV diastolic dysfunction in hypertension, there was a corresponding deterioration in LA diastolic function. Effective blood pressure control for 6 months improved LA diastolic function.

On-line assessment of left atrial area and function by echocardiographic automatic boundary detection.

Direct assessment of left atrial (LA) function has not been previously performed by noninvasive techniques; rather, LA function has been evaluated only indirectly via the analysis of transmitral flow velocity by Doppler. The recent development of real-time two-dimensional echocardiographic automatic boundary detection suggests that LA dimensions can be measured instantaneously to provide on-line assessment of its systolic and diastolic functions. We performed echocardiographic assessment of LA dimensions and function with automatic boundary detection in 45 patients by using the apical four-chamber view. Thirty-seven patients had structural or functional cardiac abnormalities, 35 patients were in sinus rhythm, and 10 patients had atrial fibrillation. Moderate to severe mitral regurgitation (MR) was noted in 16 patients. We also studied 10 control subjects to assess normal values of LA cavity area and indexes of function. From the instantaneously derived LA area, we derived indexes of systolic atrial expansion and diastolic atrial emptying. There were excellent correlations between the on-line-derived LA areas and those measured off line from videotaped images of conventional echocardiography (r = .91 for end-diastolic and .93 for end-systolic areas; SEE, 4.0 and 3.8 cm2, respectively). Patients in atrial fibrillation had depressed diastolic emptying index (0.17 +/- 0.05) compared with those in sinus rhythm (0.28 +/- 0.12; P < .02). Furthermore, patients with chronic MR exhibited larger LA cavity areas and depressed systolic and diastolic LA function as compared with those without MR. In addition, the Doppler-determined mitral E/A ratio was related to the ratio of early diastolic-to-late diastolic change in LA cavity area (r = .79; SEE 0.6; n = 35). Instantaneous LA cavity area measurement by echocardiographic automatic boundary detection is accurate and feasible in patients with diverse cardiac disorders. Patients with atrial fibrillation had a depressed diastolic emptying index and those with significant mitral regurgitation had depressed systolic expansion index as well. LA functional indexes in both systole and diastole can be derived providing an approach for quantitative evaluations of left atrial-left ventricular interactions based on geometric assessment noninvasively.