Changes In Left Atrial Dimension Research Articles

Clinical implications of left atrial changes after optimization of medical therapy in patients with heart failure.

Limited data exist regarding the prognostic relevance of changes in left atrial (LA) dimensions in patients with heart failure (HF). We assessed changes in LA dimension and their relation with outcomes after optimization of guideline-directed medical therapy (GDMT) in patients with new-onset or worsening HF. Left atrial diameter was assessed at baseline and 9 months after GDMT optimization in 632 patients (mean age 65.8 ± 12.1 years, 22.3% female) enrolled in BIOSTAT-CHF. LA adverse remodelling (LAAR) was defined as an increase in LA diameter on transthoracic echocardiography between baseline and 9 months. After the 9-month visit, patients were followed for a median of 13 further months. LAAR was observed in 247 patients (39%). Larger baseline LA diameter (odds ratio [OR] 0.90; 95% confidence interval [CI] 0.87-0.93; p < 0.001) and up-titration to higher doses of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers (ACEi/ARBs) (OR 0.56; 95% CI 0.34-0.92; p = 0.022) were independently associated with lower likelihood of LAAR. LAAR was associated with an increased risk of the composite of all-cause mortality or HF hospitalization (log-rank p = 0.007 and adjusted hazard ratio 1.73, 95% CI 1.22-2.45, p = 0.002). The association was more pronounced in patients without a history of atrial fibrillation (p for interaction = 0.009). Among patients enrolled in BIOSTAT-CHF, LAAR was associated with an unfavourable outcome and was prevented by ACEi/ARB up-titration. Changes in LA dimension may be a useful marker of response to treatment and improve risk stratification in patients with HF.

P326 Changes in left atrial dimensions during stress echocardiography: linear vs planimetric methods

Abstract OnBehalf On behalf of the Stress Echo 2020 study group of the Italian Society of Echocardiography and Cardiovascular Imaging (SIECVI) Background The measurement of left atrium (LA) can be obtained with simple linear or more complex biplane disk summation Simpson (S) method at rest and during stress echocardiography (SE). Although planimetric methods are mandatory to accurately assess resting LA volume, we sought to study if linear (L) methods can be equally valuable in assessing dynamic changes during SE. Purpose To assess accuracy of LA- SE with S compared to L method. Methods SE was performed in 34 patients (age 59 ± 16 years, 18 females) with known or suspected coronary artery disease. All had acceptable acoustic window at rest and were referred for clinically-driven SE (dobutamine in 21, dipyridamole in 13). LA was measured at rest and peak stress with both methods: 1- S biplane method from 4- and 2-chamber views; 2- L method with measurement of anteroposterior diameter from 2-D targeted M-mode in parasternal long-axis view. Two independent observers measured a set of 20 clips and repeated the measurements after 1 month on the same images. Stress-rest differences of L and S were compared with Spearman non-parametric correlation. Results LA measurement was obtained in all patients with L, 34/42 with S (feasibility 100%, and 80%, respectively). The off-line analysis time at each step (rest and stress) measured by stop-clock was 22.3 sec for L and 93 sec for S method (p &amp;lt; 0.001). The intra-rater intra-class correlation coefficient for L was 0.965 for single measures and 0.982 for average measures. For S, it was 0.830 in single measures and 0.907 for average measures. The inter-rater correlation coefficient for L was 0.920 for single measures and 0.958 for average measures. For S, it was 0.901 for single measures and 0.948 for average measures. Absolute LA dimensions were moderately correlated between S and L at rest (r = 0.61, p &amp;lt; 0.01), and during stress (r = 0.476, p &amp;lt; 0.01). Rest-stress variations were not correlated (r = 0.004, p = NS). Conclusion LA measurement is highly feasible during SE with L and S methods. Absolute values with both are only moderately correlated at rest, less at peak stress, and not correlated when only rest-to-stress variations are considered. Although L is more feasible, less time-consuming, and more reproducible, S should be the first choice for more accurate assessment of rest-stress LA dimensions in pharmacologic SE. Abstract P326 Figure. Correlation of LA rest-stress

Long‐Term Follow‐up Impact of Dual‐Chamber Pacing on Patients with Hypertrophic Obstructive Cardiomyopathy

Pacing has been proposed as a treatment for patients with hypertrophic obstructive cardiomyopathy (HOCM), but there are few studies with long-term follow-up. We evaluated the long-term effects of dual-chamber pacing therapy for patients with HOCM, and to identify the most prognosis-specific factors for predicting outcome in such treating methods. A total of 37 HOCM patients implanted with dual-chamber pacemakers were enrolled consecutively and followed-up. Thirty-seven cases were followed for 1 year, 26 cases for 2 years, 10 cases for 3 years, and eight cases for 4 years. At each annual point of follow-up after pacemaker implantation, the pacing frequency, pacing threshold, impedance, atrioventricular delay, and cumulative percentage of atrial and ventricular pacing were tested, respectively. In addition, left atrial dimension (LAD), left ventricular end diastolic dimension (LVEDd), left ventricular posterior wall thickness (LVPW), interventricular septum thickness (IVS), left ventricular outflow tract dimension (LVOTd), peak velocity of left ventricular outflow tract (VLVOT), left ventricular outflow tract pressure gradient (LVOTPG), left ventricular ejection fraction (LVEF), and pulmonary artery systolic pressure (PASP) were measured. Mitral valve systolic anterior motion (SAM) was also observed. Pacing parameters and echocardiography indexes before and after pacemaker implantation were dynamically compared. Pacing frequency and atrioventricular delay were adjusted to 60-70 beats per minute and 90-180 ms, respectively, in order to ensure the ratio of ventricular pacing was more than 98%. Pacing threshold and pacing impedance were kept in normal ranges. The differences of various pacing parameters were of no statistical significance within the 4 years of follow-up (P > 0.05). Compared with prior to pacing, it was observed that the IVS, VLVOT, and LVOTPG declined significantly (P < 0.01), the LVOTd widened significantly (P < 0.01), and the SAM phenomenon improved obviously (P < 0.01) at 1, 2, 3, and 4 years after pacemaker implantation. Additionally, the changes in LAD, LVEDd, LVPW, LVEF, and PASP were statistically insignificant (P > 0.05). The cardiac structural reconstruction in patients with HOCM can be chronically improved by dual-chamber pacing therapy. The IVS, LVOTd, VLVOT, and LVOTPG can be used as sensitive and specific factors in evaluating the long-term effects of dual-chamber pacing therapy for HOCM.

Randomized trial of angiotensin II-receptor blocker vs. dihydropiridine calcium channel blocker in the treatment of paroxysmal atrial fibrillation with hypertension (J-RHYTHM II Study)

Atrial fibrillation (AF) is a common arrhythmia frequently associated with hypertension. This study was designed to test the hypothesis that lowering blood pressure by angiotensin II-receptor blockers (ARB) has more beneficial effects than by conventional calcium channel blockers (CCB) on the frequency of paroxysmal AF with hypertension. The Japanese Rhythm Management Trial II for Atrial Fibrillation (J-RHYTHM II study) is an open-label randomized comparison between an ARB (candesartan) and a CCB (amlodipine) in the treatment of paroxysmal AF associated with hypertension. Using daily transtelephonic monitoring, we examined asymptomatic and symptomatic paroxysmal AF episodes during a maximum 1 year treatment. The primary endpoint was the difference in AF frequency between the pre-treatment period and the final month of the follow-up. The secondary endpoints included cardiovascular events, development of persistent AF, left atrial dimension, and quality-of-life (QOL). The study enrolled 318 patients (66 years, male/female 219/99, 158 in the ARB group and 160 in the CCB group) treated at 48 sites throughout Japan. At baseline, the frequency of AF episodes (days/month) was 3.8 ± 5.0 in the ARB group vs. 4.8 ± 6.3 in the CCB group (not significant). During the follow-up, blood pressure was significantly lower in the CCB group than in the ARB group (P < 0.001). The AF frequency decreased similarly in both groups, and there was no significant difference in the primary endpoint between the two groups. There were no significant differences between the two groups in the development of persistent AF, changes in left atrial dimension, occurrence of cardiovascular events, or changes in QOL. In patients with paroxysmal AF and hypertension, treatment of hypertension by candesartan did not have an advantage over amlodipine in the reduction in the frequency of paroxysmal AF (umin CTR C000000427).

Left atrial wall tension directly affects the restoration of sinus rhythm after Maze procedure

The surgical treatment of permanent atrial fibrillation (AF) continues to be a clinical challenge. Increased left atrial (LA) wall tension affected by LA wall thickness and volume has been associated with poor restoration of sinus rhythm after the Maze procedure. This study was designed to investigate the impact of conversion rates to sinus rhythm using LA wall tension reduction techniques in conjunction with aggressive postoperative pharmacological therapy in comparison to a modified Maze procedure alone. From 1999 to 2008, 322 patients with permanent AF and biatrial enlargement, who required mitral valve ± tricuspid valve surgery were exactly randomized into two groups: The study group used biatrial reduction with reef-imbricate suture technique concomitant with the Maze procedure and aggressive postoperative pharmacological therapy; the control group was treated with the Maze procedure alone. LA dimension was measured by transesophageal echocardiogram (TEE) or transthoracic echocardiography (TTE); LA wall thickness was measured by TEE and manually during surgery. Pulmonary artery (PA) pressures were measured by PA catheter or TTE, BNP test and clinical follow-up at discharge, 3 months, 6 months and 1 year. There were 187 woman (58%) and 135 men (42%). Their mean age was 45 ± 9.5 years. Overall restoration of sinus rhythm was significantly improved in the group with aggressive reduction of LA wall tension during 1-year clinical follow-up (89.3% vs 67.2%, p < 0.001). Calculated LA wall tension was significantly reduced at discharge in the study group versus control group (4.012 ± 1.650 dyn cm(-1) vs 20 384 ± 3313 dyn cm(-1) (p < 0.001)) and at 1-year follow-up (1059 ± 1161 dyn cm(-1) vs 17 139 ± 3170 dyn cm(-1) (p < 0.001)), respectively. Significant differences in changes in LA dimension were detected at discharge and 1-year follow-up in the study group versus control group (43 ± 7 vs 61 ± 11, p < 0.001). LA wall (3.9 ± 1.3 vs 2.3 ± 0.9) thickness also significantly differed at the 1-year follow-up. An aggressive approach to reduce LA wall tension significantly improves restoration of sinus rhythm after the Maze procedure. LA wall tension directly affects sinus conversion. Further studies using pharmacologic intervention to reduce LA wall tension for maintenance of sinus rhythm need to be evaluated.

Changes in left atrial dimension and function and left ventricular geometry in newly diagnosed untreated hypertensive subjects

It is known that a spectrum of changes in structure, size and function of the different chambers of the heart occur in individuals with hypertension. The earliest changes and the sequence of these changes are still being studied. The present study aimed to assess early changes in the left atrial size and function in hypertension, and its relationship with left ventricular geometry and other factors that may influence left atrial size. One hundred consecutive subjects who were newly diagnosed with hypertension and 50 apparently normal individuals were recruited into the study. Standard M-mode, two-dimensional and Doppler echocardiography were performed. The endocardial border of the left atrium was traced to obtain the atrial area and left atrial volumes and emptying fractions were derived from measured areas. The hypertensive patients and the controls were comparable by age, sex and body mass index. Thirty-seven (37%) of the hypertensive subject had increased left ventricular mass versus eight subjects (16%) in the normal controls. The patients with hypertension had a higher linear left atrial dimension (3.5 +/- 0.48 cm versus 3.1 +/- 0.47 cm, P < 0.0001), longer pre-atrial contraction length (3.8 +/- 0.56 cm versus 3.6 +/- 0.45 cm; P = 0.02) and higher peak late mitral inflow velocity (0.64 +/- 0.19 m/s versus 0.56 +/- 0.15 m/s; P = 0.010). Changes in the geometry of the left ventricle occur early in hypertension and precede deterioration in left ventricular systolic function. The corresponding left atrial changes are marginal and are indicative of increased left atrial length and accentuated atrial systolic function.

Mechanisms of release of atrial natriuretic factor in vivo.

The aim of the study was to define the relationship between the concentration of immunoreactive atrial natriuretic factor (ANF) in the plasma and atrial stretch, atrial pressure and atrial wall stress during changes in blood volume within the physiological range. Advantage was taken of the potentiation of the release of ANF, in response to blood volume expansion, in the anaesthetized rabbit, by section of the carotid sinus, aortic depressor and vagus nerves. Mean arterial pressure and right and left atrial pressures were measured. Right and left atrial dimensions were measured by sonomicrometry. Blood volume was expanded by 20% and then decreased at 1% of the blood volume per minute for 40 min, before and after section of the nerves. Plasma ANF did not change significantly in response to either the increase or decrease in blood volume in the presence of intact nerves. After the nerves were sectioned, blood volume expansion significantly increased IR-ANF (34.6 +/- 12 to 260.6 +/- 89.8 pg/ml). The relationship between ANF and the changes in left atrial dimensions (extension ratio) was exponential. A significant linear correlation was found between ANF and left atrial pressure and left atrial wall stress. Over a range of atrial pressures from 1-10 cm H2O the atrial wall was extremely distensible, but there were only minor changes in ANF. At higher atrial pressures there was little further extension of the atrial wall but there were much larger increases in plasma ANF. In response to changes in blood volume within the physiological range cardiovascular reflexes normal maintain atrial dynamic function within a narrow range and there is little stimulus for the release of ANF. In conditions in which the cardiovascular reflexes are unable to maintain atrial function constant then there will be changes in the release of ANF and there will be an exponential relationship between atrial wall stretch and plasma ANF.

Effect of dynamic exercise on left atrial function in conscious dogs.

1. Dynamic changes in left atrial (LA) function during treadmill exercise were studied in ten conscious dogs instrumented to measure left ventricular (LV) pressure and diameter, LA pressure and diameter, and pulmonary venous blood flow (PVF, transit time flowmeter). 2. Systolic PVF volume (reservoir volume; a measure of LA reservoir function) increased from 38 +/- 4% of total PVF volume at baseline to 52 +/- 8% of total PVF volume during exercise, and diastolic PVF volume (conduit volume; a measure of LA conduit function) decreased from 62 +/- 5% at baseline to 48 +/- 8% during exercise (P < 0.005). 3. The increases in reservoir volume and the decrease in conduit volume were due not only to a greater decrease in diastolic interval than systolic interval but were also caused by a significantly greater increase (P < 0.05) in the mean systolic filling rate (93%) than in the mean diastolic filling rate (51%). 4. During exercise the pattern of LV filling derived from changes in LV diameter showed that a greater percentage of LV filling occurred during the second half of diastole at the time of atrial contraction (P < 0.05), suggesting that LA booster function was enhanced. 5. Changes in LA dimension revealed that during exercise more blood volume was reserved in the LA during systole and that this change was associated with an increase in the LA dimension at the beginning of LA contraction (r = 0.61, P < 0.05). 6. We conclude that LA reservoir and booster functions were augmented during exercise, whereas conduit function was not. Increased reservoir function may play an important role in accelerating LV filling by helping to maintain an enhanced atrioventricular pressure gradient during diastole and also by increasing LA booster function through an increase in LA preload.

Aortic root and left atrial wall motion. An echocardiographic study.

The echocardiographically recorded movement of the aortic root was studied by analysing the relation between posterior aortic wall motion and other intracardiac events. The systolic anterior movement of the aortic root continued beyond aortic valve closure and in cases with mitral regurgitation began significantly earlier than in normal subjects. The diastolic rapid posterior movement began after mitral valve opening but did not occur in patients with mitral stenosis. The total amplitude of aortic root motion was increased in patients with mitral regurgitation, diminished in cases of mitral stenosis, and was normal with aortic regurgitation. In patients with atrioventricular block an abrupt posterior movement followed the P wave of the electrocardiogram irrespective of its timing in diastole. These observations correlate with the expected changes in left atrial volume during the cardiac cycle both in the normal subjects and patients with heart disease. The results support the hypothesis that phasic changes in left atrial dimension are largely responsible for the echocardiographically observed movement of the aortic root and indicate a potential role for echocardiography in the analysis of left atrial events.

Echocardiographic abnormalities in acute rheumatic fever

The echocardiographic velocity of circumferential fiber shortening and left atrial dimension were measured serially in two groups of children with acute rheumatic fever: Group I, six patients with valve regurgitation without congestive heart failure, and Group II, seven patients with regurgitation and congestive heart failure. In Group I, the initial velocity of circumferential fiber shortening was increased to 1.90 ± 0.31 circumferences per second (circ/sec) (mean ± standard deviation). In Group II, it was decreased (1.18 ± 0.25 circ/sec). In Group I velocity of circumferential fiber shortening subsequently decreased but remained above the normal level; in Group II it increased to exceed the expected normal value. Concurrent changes in left atrial dimension were observed in both groups. The initial left atrial dimension of Group I (2.2 ± 0.75 cm/m 2) was slightly increased and returned to normal (1.70 ± 0.32) on follow-up study. The left atrial dimension of Group II was greatly increased initially (2.70 ± 0.81 cm/m 2) and remained large (2.50 ± 0.67). Three patients in Group II experienced rebound during corticosteroid withdrawal. In each the velocity of circumferential fiber shortening decreased, suggesting impaired cardiac contractility. The echocardiogram thus facilitates serial assessment of the severity of carditis in acute rheumatic fever.