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At least 217 records · Page 12Linked to original sources
PubMed2001

Predictors for atrial transport function after mini-maze operation.

BACKGROUND: Restoration of atrial transport function (ATF) is a major goal of the maze procedure. This prospective study was undertaken to evaluate predictors of left atrial transport function in patients undergoing a mini-variant of the maze III procedure 3 and 12 months postoperatively. METHODS: Mini-maze operation was performed in 72 patients with a mean age of 64 +/- 8.7 years during a 5-year period. Seventy of 72 (97%) had combined procedures. Clinical and electrophysiologic examination was carried out before surgery, and 3 and 12 months postoperatively. RESULTS: Early mortality was 1.4% (1 of 72 patients) and late death occurred in 5.6% (4 of 71 patients). After 3 months, 54 of 68 (80%) patients showed sinus rhythm, and 48 of 60 (80%) after 12 months. ATF was restored in 87% (echocardiography) and 82% (magnetic resonance imaging) after 3 months, and in 86% (echocardiography) and 78% (magnetic resonance imaging) after 12 months. Independent predictors for ATF restoration after 12 months were better preoperative left ventricular function (p = 0.02), and smaller preoperative left atrial diameter (p = 0.005). Correlation between echocardiography and magnetic resonance imaging was 80% after 12 months. CONCLUSIONS: Restoration of ATF after mini-maze procedure is achieved in over 80%. Independent predictors for ATF restoration are smaller preoperative left atrial diameter and better preoperative left ventricular ejection fraction.

Adult↗
PubMed1993

Atrial ejection force: a noninvasive assessment of atrial systolic function.

OBJECTIVES: The purpose of this study was to define atrial ejection force and to develop a method for its noninvasive measurement from echocardiographic data. BACKGROUND: Assessment of diastolic function through measurement of the components of ventricular filling has largely neglected the vigor of atrial systole, in part because this has been difficult to quantify. However, atrial ejection force, defined as that force exerted by the left atrium to accelerate blood into the left ventricle during atrial systole, can be assessed noninvasively by combined two-dimensional imaging and Doppler echocardiography. This index of atrial function, based on classic newtonian mechanics, provides a physiologic assessment of atrial systolic function. METHODS: To evaluate the usefulness of atrial ejection force, we studied the return of left atrial ejection force in 29 patients after elective cardioversion for atrial fibrillation. Transmitral Doppler inflow patterns at rest were assessed immediately after cardioversion and at 24 h, 1 week, 1 month and > 3 months later. A healthy adult group (n = 10) served as control subjects. RESULTS: After successful cardioversion, atrial ejection force was significantly depressed compared with that in the control group (5.2 +/- 6.8 vs. 16.3 +/- 4.7 kdynes; p < 0.0001). Over successive weeks, atrial ejection force improved in the subgroup of patients who remained in sinus rhythm (n = 18), whereas no improvement was seen during the period of maintained sinus rhythm in the patients with subsequent reversion to atrial fibrillation (n = 11). CONCLUSIONS: Atrial ejection force provides a physiologic assessment of atrial systolic function and is a potentially useful index for assessing atrial contribution to diastolic performance. In patients who successfully underwent cardioversion from atrial fibrillation, atrial ejection force improved over several weeks only in the subgroup in which sinus rhythm was maintained.

Adult↗
PubMed2000

Left atrial appendage function in patients with cardioembolic stroke in sinus rhythm and atrial fibrillation.

The purpose of this study was to determine the left atrial appendage (LAA) function in patients with stroke. The study group consisted of 61 patients with stroke and 37 control subjects. Patients with stroke were divided into 2 groups on the basis of the presence of atrial fibrillation (group 1) or sinus rhythm (group 2). Group 1 showed a significant reduction of LAA flow velocities (13.2 +/- 6.4 cm/s versus 27.5 +/- 8 cm/s, P <.05) and significant increase in LAA areas (minimum area: 360.5 +/- 204 mm(2) versus 217.7 +/- 113.9 mm(2), P =.004). Group 2 showed a decrease in LAA flow velocities (17.7 +/- 8.2 cm/s versus 27.5 +/- 8 cm/s, P <.05), but no significant change was found in LAA areas. No significant difference was found in other parameters related to LAA. These findings show that a decreased LAA flow velocity is a risk factor for stroke in patients in sinus rhythm without LAA enlargement. Left atrial appendage area was increased in size only in patients with atrial fibrillation.

Adult↗
PubMed1997

[Pharmacological cardioversion of isolated atrial fibrillation: recovery of atrial mechanical function and correlation with duration of arrhythmia].

To evaluate how the duration of atrial fibrillation before cardioversion affects the recovery of atrial systolic function, serial transthoracic pulsed Doppler echocardiographic studies were performed within 2 hours and at 2 days, 7 days, 1 month and 2 months after chemical cardioversion to sinus rhythm. Peak A wave velocity (A), velocity time integral of A wave (A-VTI) and percent A-wave filling (A/VTI-tot) were assessed in 60 patients with lone atrial fibrillation of brief (> or = 12 to < or = 72 hours, 20 patients), moderate (> 72 hours to < or = 4 weeks, 20 patients) or prolonged (> 4 to < or = 24 weeks, 20 patients) duration. The three groups were well matched for age and left atrial size and none of the patients underwent antiarrhythmic therapy during follow-up. Atrial mechanical function is greater immediately and at 2 and 7 days after cardioversion in patients with brief atrial fibrillation, as compared moderate and prolonged atrial fibrillation (A and A/VTI-tot values: p < 0.05, p < 0.005 and p < 0.05, respectively). In addition, at 7 days after cardioversion, atrial systolic function is greater in patients with moderate atrial fibrillation as compared to prolonged atrial fibrillation (A value, p < 0.005 and A/VTI-tot value, p < 0.05). In all groups, atrial mechanical function increases over time and ultimately achieves similar levels. Full recovery of atrial mechanical function is achieved within 2 days in patients with brief atrial fibrillation, within 7 days in patients with atrial fibrillation of moderate duration and within 1 month in patients with prolonged atrial fibrillation. Recovery of the mechanical function of the left atrium is related to the duration of atrial fibrillation before cardioversion. These findings have important implications for assessing the early hemodynamic benefits of successful cardioversion.

Adult↗
PubMed1991

Mechanism of augmented left atrial pump function in myocardial infarction and essential hypertension evaluated by left atrial pressure-dimension relation.

To analyze left atrial (LA) pump function in normal subjects, in patients with essential hypertension and in patients with a healed myocardial infarction, LA dimension (aortic-root echogram) and pressure (catheter-tip manometer) were simultaneously recorded in 25 patients (8 normal subjects, 7 with hypertension and 10 with myocardial infarction). The pressure-dimension relation of the left atrium was composed of 2 loops: the A loop (expressing the pump function of the left atrium) and the V loop. LA dimension at the beginning of active LA shortening was significantly greater in hypertensive subjects (33 +/- 3 mm) and in those with myocardial infarction (32 +/- 4 mm) than in normal subjects (28 +/- 3 mm) (p less than 0.01, p less than 0.05, respectively). The area of the A loop significantly increased in subjects with hypertension (48 +/- 3 mm Hg.mm, p less than 0.01) and in subjects with myocardial infarction (29 +/- 10 mm Hg.mm, p less than 0.05), compared with normal subjects (20 +/- 8 mm Hg.mm). The mean fractional shortening velocity of the left atrium significantly increased in subjects with hypertension, compared with normal subjects and those with myocardial infarction (p less than 0.05 for both). LA peak wall tension during the LA active contraction period significantly increased with hypertension and with myocardial infarction, compared with normal subjects (p less than 0.01, p less than 0.05, respectively). The area of the A loop was directly proportional to the LA dimension at the beginning of active LA shortening (r = 0.53), p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

[Endocrine function of the heart. Structure and biological properties of peptides secreted by the heart atrium].

Apart from the generally known functions, the heart has also an endocrine function. Atrial cardiocytes, being typical secretory cells, release peptide hormones into the blood stream: atrial natriuretic peptide containing 28 amino acids and cardiodilatin. The structure of atrial peptides was determined. It was shown that both peptides were derived from their common precursor, a protein containing 151 amino acids. The presence of specific receptors is demonstrated on plasmatic membranes of cells of kidney epithelium, arterial smooth muscle, arterial endothelium, kidney cortex and hypophysis. The interaction of atrial peptides with these receptors activates the guanylate cyclase system. The biological action of atrial peptides manifests itself in the quick, massive and instantaneous increase of diuresis and electrolyte excretion, elevated clearance of creatinine, decrease of kidney vascular resistance, intensification of glomerular filtration, inhibition of stimulated secretion of aldosterone, relaxation of blood vessels, elimination of arterial and intestinal spasm induced by various endogenous and exogenous vasoconstrictors and in correction of kidney hypertension. Various radioimmunoassays for the presence of atrial peptides in human plasma were developed; it was shown that in patients with congestive heart failure the content of atrial peptides is increased.

Amino Acid Sequence↗
PubMed1985

The role of the atria in fluid volume control.

Neural reflexes from the heart, in particular the atria, are well documented and are involved in sodium and water excretion. Current work also indicates that the atria have an important endocrine function. Atrial peptides, which have been recently characterized and synthesized, may play a significant role in the homeostasis of body fluids.

Animals↗
PubMed1989

Atrial wall function and plasma atriopeptin during volume expansion in conscious dogs.

Mean left atrial pressure is believed to be an accurate estimate of atrial stretch in vivo and is used to assess the stimulus for atriopeptin release in both animals and humans. However, for a number of years it has been known that atrial stretch receptor discharge occurs during specific phases of the atrial cycle and that B-receptor discharge correlates with the passive filling of the atrium, which occurs during the V wave. The purpose of this study was to develop the concept that phase-specific changes in atrial wall stress are responsible for atriopeptin secretion. In chronically instrumented conscious dogs, volume expansion (1,000 ml of saline in 5 min) increased left atrial pressure and dimensions and caused a 663 +/- 189% increase in plasma immunoreactive atriopeptin from 44 pg/ml. At this time, mean left atrial pressure increased only 202 +/- 36% (mean +/- SE), whereas A wave pressure increased 146 +/- 19% and V wave pressure increased 290 +/- 67%. A and V wave dimensions increased only a few percent. After developing atrial wall thickness constants for diastole (KCl fixation) and systole (BaCl2 fixation), calculated atrial A wave wall stress increased 163 +/- 25%, and V wave wall stress increased 346 +/- 85%. Minute wall stress (wall stress times heart rate) gave an even better correlation with changes in plasma atriopeptin. V wave minute wall stress increased 690 +/- 168%, whereas A wave wall stress increased 366 +/- 56%.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1998

Left atrial and left atrial appendage functional abnormalities in patients with cardioembolic stroke in sinus rhythm and idiopathic atrial fibrillation.

Thrombogenesis in the left atrial appendage (LAA) has been related to the special morphology of this cavity and to its size and degree of dysfunction. However, no study has focused on LAA function in conjunction with left atrial (LA) function in both sinus rhythm (SR) and nonrheumatic idiopathic atrial fibrillation (AF) in relation to clinical status (cardioembolic stroke). Forty-three patients in SR (14 patients with stroke, 29 control subjects) and 45 patients in AF (27 patients with stroke, 18 control subjects) were examined by transthoracic and transesophageal echocardiography. Baseline clinical characteristics and standard transthoracic and transesophageal measurements of the LA and LAA (size, fractional area change, flow measurements, spontaneous echo contrast, and thrombus) were recorded and compared in relation to cardiac rhythm. Patients in the stroke-SR group showed a significant decrease of fractional area change in the LA (32%+/-15%) and LAA (34%+/-15%) in relation to control subjects (43%+/-10%, p = 0.035, 49%+/-13%, p = 0.006, respectively). Patients in the stroke-AF group showed significant reduction of appendage flow measurements (outward velocity = 22+/-13 vs 33+/-19 cm/sec, p = 0.036), whereas no differences were detected in the center of the LA. In multiple regression analysis, the presence of cardioembolic stroke was positively associated with the presence of spontaneous echo contrast (p = 0.0253) and spontaneous echo contrast negatively associated with appendage inward flow velocity (p<0.001). Cardioembolic stroke in patients in SR is associated with a global decrease of shortening in both cavities and in patients with AF, with a reduction of LAA flow parameters. Patients with spontaneous echo contrast, thrombus, or both showed further reduction of shortening and flow velocities in both cavities, indicating a more advanced stage of dysfunction.

Aged↗
PubMed1998

Left atrial appendage function assessed by transesophageal echocardiography before and on the day after elective cardioversion for nonvalvular atrial fibrillation.

We investigated left atrial appendage function by transesophageal echocardiography, on the day after external electrical cardioversion to sinus rhythm, in 41 patients with nonvalvular atrial fibrillation. After cardioversion, appendage contraction synchronized with the electrical and mechanical activity of the atrium, which was restored in about 70% of the patients.

Adult↗
PubMed1998

Severely reduced left atrial appendage function: a cause of embolic stroke in patients in sinus rhythm?

Recently, attention has been focused on transesophageal echocardiographic detection of left atrial appendage function to assess of risk of thrombus formation because of potential benefit of anticoagulation therapy. However, most of these studies have been conducted in patients with atrial fibrillation or mitral valve disease. In this article we review cases of 2 patients without valvular disease who had embolic stroke in sinus rhythm. Transesophageal echocardiography revealed thrombi in the left atrial appendage in both patients. The left atrial appendage function in these patients was compared with that in patients with chronic atrial fibrillation and a control group in sinus rhythm. Left atrial appendage function in the patients with stroke and sinus rhythm was significantly lower than that of patients in the control group in sinus rhythm (P < .001) and was similar to the appendage function in patients with chronic atrial fibrillation. These observations provide further evidence that the finding of reduced left atrial appendage function can be a cause of stroke in patients with sinus rhythm even in the absence of mitral valve disease. Reduced left atrial appendage function may identify patients with unexplained stroke who should receive anticoagulation therapy even in the absence of detectable appendage thrombi.

Adult↗
PubMed1998

Restoration of atrial mechanical function after maze operation in patients with structural heart disease.

BACKGROUND: The maze operation is effective for the restoration of sinus rhythm; however, restoration of atrial mechanical function has not been demonstrated in all patients. METHODS: Maze operations were performed in 32 patients (13 men, 19 women; mean age 47.1 +/- 9.0 years) combined with valvular surgery (n = 25), coronary artery bypass graft (CABG) (n = 3), and others (n = 4). At 1 week, 3 months, 6 months, and 1 year after the operation, prospective serial Doppler echocardiographic examination was carried out to determine the presence of atrial mechanical function. RESULTS: Sinus rhythm was restored and maintained during the follow-up period in 26 (81%) patients; in 22 patients this was due solely to the operation, whereas in four patients an antiarrhythmic agent was needed to maintain sinus rhythm. Another four patients showed paroxysmal atrial fibrillation (AF) despite treatment with an antiarrhythmic agent. Right atrial mechanical function was restored in all 30 patients with sinus rhythm or paroxysmal AF; in 19 (63%) of these, left atrial mechanical function was restored. In patients with restored left atrial mechanical function, peak A velocity (A) and A/E ratio (A/E) of mitral inflow were significantly lower than in the 16 postoperative control patients (A: 0.46 +/- 0.14 m/sec vs 0. 75 +/- 0.29 m/sec, p < 0.01; A/E: 0.40 vs 0.80, p < 0.01). In patients with left atrial mechanical function, the duration of AF was significantly shorter than in patients without left atrial mechanical function (1.9 +/- 2.9 years vs 7.1 +/- 3.0 years, p < 0. 01), but there were no significant differences in left atrial size and volume. CONCLUSIONS: The maze operation could be safely added to standard open heart surgery for the correction of underlying structural heart disease. The rate of conversion to sinus rhythm resulting solely from the operation might be lower than the rates previously reported with only the duration of AF adversely affecting the restoration of left atrial mechanical function. Considering the fact that not all patients converted to sinus rhythm show atrial mechanical function, the role of the maze operation in the prevention of systemic embolism, with subsequent improvement in survival, requires further study.

Adult↗
PubMed2000

Noninvasive indexes of left atrial diastolic function in hypertrophic cardiomyopathy.

OBJECTIVES: Our goal was to noninvasively assess left atrial diastolic function and its relation to the impaired left ventricular filling in patients with hypertrophic cardiomyopathy. METHODS AND RESULTS: We studied 34 patients with hypertrophic cardiomyopathy, 26 patients with secondary forms of left ventricular hypertrophy (aortic stenosis, fixed subaortic stenosis, hypertension), and 21 control subjects. Left atrial diastolic function was assessed by measuring acceleration time (SAT), deceleration time (SDT), and the EF (mean deceleration rate) slope of the pulmonary venous flow systolic wave (SW). Left ventricular diastolic function assessed by transmitral Doppler included peak early left ventricular and peak atrial filling velocities, the ratio of early-to-late peak velocities, isovolumic relaxation time, deceleration time, and EF slope. In patients with hypertrophic cardiomyopathy, acceleration time was significantly reduced (P<.05), deceleration time was significantly prolonged (P<.0001), and EF slope was significantly reduced (P<.01). These indexes were similar among the other two groups. No statistically significant difference existed between the subgroups of hypertrophic cardiomyopathy in the above indexes. Patients with hypertrophic cardiomyopathy and secondary forms of left ventricular hypertrophy had evidence of left ventricular diastolic dysfunction. In patients with hypertrophic cardiomyopathy, no correlation existed between left atrial and left ventricular diastolic function indexes (r = -0.26 to 0.33). CONCLUSIONS: Echocardiographic indexes of left atrial relaxation and filling are abnormal in patients with hypertrophic cardiomyopathy but not in secondary forms of left ventricular hypertrophy. These indexes are abnormal in all forms of hypertrophic cardiomyopathy irrespective of left ventricular outflow tract obstruction and distribution of hypertrophy; they are not solely attributable to left ventricular diastolic dysfunction. The above may imply that hypertrophic cardiomyopathy is a cardiac myopathic disease that involves the heart muscle as a whole, irrespective of distribution of hypertrophy and obstruction.

Adolescent↗
PubMed1996

Transesophageal echocardiographic evaluation of left atrial appendage function and spontaneous contrast formation after chemical or electrical cardioversion of atrial fibrillation.

Changes in left atrial (LA) appendage pulsed-wave Doppler velocities and changes in grades of spontaneous contrast occur immediately after electrical cardioversion of atrial fibrillation (AF) using transesophageal echocardiography (TEE). The effect of sequential ineffective electrical cardioversion attempts or chemical cardioversion on these parameters is unknown. TEE was performed in 23 patients with chronic AF. Doppler velocities and grades of spontaneous contrast were assessed before and after each cardioversion attempt until sinus rhythm was achieved. Doppler emptying and filling velocities were significantly decreased after electrical (0.39 +/- 0.14 vs 0.27 +/- 0.16 [p = 0.01] and 0.43 +/- 0. 18 vs 0.30 +/- 0.14 m/s [p = 0.01]) or chemical cardioversion to sinus rhythm (0.65 +/- 0.18 vs 0.31 +/- 0.06 [p = 0.03] and 0.64 +/- 0.22 vs 0.44 +/- 0.17 m/s [p = 0.04]). Spontaneous contrast developed in 1 of 3 patients after chemical conversion to sinus rhythm and was present in 11 of 20 patients before electrical cardioversion, developing in 4 patients and intensifying in 2 patients immediately after successful cardioversion. These phenomena were not seen after ineffective electrical or chemical cardioversion attempts. This suggests that restoration of sinus rhythm is in itself responsible for these phenomena, not the method by which sinus rhythm is achieved.

Aged↗
PubMed1995

[The rate of recovery of left atrial contractile function after the transition to sinus rhythm in patients with paroxysmal atrial fibrillation].

In the examination of 120 patients without valvular heart disease suffering from atrial fibrillation paroxysms mechanical function of the left atrium (LA) was assessed using Doppler echocardiography. The majority of the examinees had dilated LA which is thought to be arrhythmogenic. The recovery of the sinus rhythm is accompanied by electromechanical dissociation the longest duration of which took place in subjects exposed to electrical defibrillation. An inverse relationship was established between the time of the last fibrillation and recovery of LA mechanical function. The duration of the electromechanical dissociation of the atria holds prognostic importance in relation to recurrent fibrillation.

Adult↗
PubMed1996

Dependence of atrial sensing function on posture in a single-lead atrial triggered ventricular (VDD) pacemaker.

The influence of body posture on atrial sensing was examined in a single-lead VDD pacemaker in 16 patients. At implantation, a position was searched for the floating atrial bipolar sensor to obtain an adequate atrial signal amplitude. After 1-12 months the atrial signals were measured by programming the sensitivity in five postures: supine, sitting, and standing and lying on the right and left sides. The group mean amplitudes of the atrial signal were equal in all postures, and comparable to the supine value (1.01 +/- 0.51 mV). However, the values within each individual varied considerably according to position, by a range of 0.46 +/- 0.41 mV on average. Testing only supine did not always predict decent sensing when upright, e.g., in 3 patients the atrial signal decreased more than 0.5 mV. In 24-hour ambulatory electrocardiography, with the sensitivity (0.15-0.30 mV) set to cover all postures, atrial beats were undersensed not at all in 4 patients, < 0.01% in 6 patients, and < 0.1% in the remaining 6 patients. Thus, with a floating atrial electrode, sensitivity testing in various postures is advisable to ascertain proper sensing function.

Aged↗
PubMed1998

Effect of direct current shocks on left atrial mechanical function in patients with structural heart disease.

OBJECTIVES: This study examined the effect of endocardial and transthoracic direct current (DC) shocks on left atrial and left atrial appendage function in humans with structural heart disease. BACKGROUND: DC cardioversion of atrial fibrillation (AF) to sinus rhythm is associated with transient left atrial and left atrial appendage dysfunction and the development of spontaneous echo contrast (SEC). This phenomenon has been termed atrial "stunning" and may be associated with thrombus formation and embolic stroke. To what extent the shock itself contributes to atrial stunning is unclear. METHODS: Thirteen patients in sinus rhythm undergoing implantation of a ventricular implantable cardioverter defibrillator (ICD) were prospectively evaluated. All patients had significant structural heart disease. To evaluate the effects of DC shocks on left atrial and left atrial appendage function, biphasic R wave synchronized endocardial shocks of 1, 10 and 20 J were delivered between the right ventricular electrode and the left pectoral generator of the ICD in sinus rhythm. R wave synchronized transthoracic shocks of 360 J were also delivered between anteriorly and posteriorly positioned chest electrodes. Transesophageal echocardiography was performed to evaluate left atrial appendage velocities, mitral inflow velocities and the presence of SEC before and immediately after each DC shock. RESULTS: There were no significant changes in left atrial or left atrial appendage function after endocardial or transthoracic DC shocks. Left atrial SEC did not develop after endocardial or transthoracic DC shocks. CONCLUSIONS: Endocardial and transthoracic DC shocks are not directly responsible for left atrial and left atrial appendage stunning and do not contribute to the stunning that is observed after the cardioversion of AF to sinus rhythm.

Aged↗