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PubMed2000

Lipoprotein(a), left atrial appendage function and thromboembolic risk in patients with chronic nonvalvular atrial fibrillation.

Lipoprotein(a) (Lp(a)) has a prothrombotic effect by modulating the fibrinolytic system. The purpose of the present study was to determine whether serum Lp(a) levels are associated with an increased risk of thromboembolism in chronic nonvalvular atrial fibrillation (NVAF). Clinical, laboratory and transesophageal echocardiographic data were collected in 172 consecutive, non-anticoagulated patients with chronic NVAF. Thirty-four patients (thromboembolic group) had a recent (<1 month) embolic event and/or a left atrial thrombus on transesophageal echocardiography. The thromboembolic group had a higher frequency of spontaneous echo contrast (94 vs. 58%, p<0.0001), increased concentrations of Lp(a) (median: 31.5 vs. 15.5 mg/dl, p<0.0001) and fibrinogen (median: 352 vs. 314 mg/dl, p = 0.0015), larger left atrial dimensions (median: 5.1 vs. 4.8cm, p = 0.0078), and reduced left atrial appendage (LAA) flow velocities (median: 9.5 vs. 21.2 cm/s, p<0.0001) than the nonthromboembolic group. Multivariate analysis identified 3 independent predictors of thromboembolism: Lp(a) level > or =30 mg/dl (odds ratio (OR) 9.5, 95% confidence interval (CI) 4.4-20.4, p<0.0001), LAA flow velocity of <20 cm/s (OR 8.7, 95% CI 3.3-23.0, p = 0.0003) and a fibrinogen concentration of <377mg/dl (OR 3.2, 95% CI 1.5-6.9, p = 0.0201). The Lp(a) elevations and reduced LAA flow velocities are independently associated with thromboembolism in chronic NVAF.

Aged↗
PubMed2001

Assessment of left atrial appendage function and its relationship to pulmonary venous flow pattern by transesophageal echocardiography.

We evaluated left atrial appendage function and its relationship to pulmonary venous flow in 53 patients divided into four groups. Group 1 consisted of 10 normal subjects. Group 2 included 15 patients with significant pure mitral stenosis in sinus rhythm. In group 3, there were 13 patients with pure significant mitral stenosis and atrial fibrillation. Group 4 consisted of 15 patients with normal mitral valve and atrial fibrilltion. We found significant decrease in left atrial appendage ejection fraction and maximum emptying flow velocity, velocity time integral of systolic pulmonary venous flow in Groups 2, 3 and 4 in comparison with normal subjects. Systolic pulmonary venous flow velocity was significantly decreased in Groups 3 and 4. There was significant correlation between left atrial appendage ejection fraction and peak emptying flow velocity (r = 0.62, P < 0,001). Systolic peak pulmonary venous flow velocity was significantly correlated with left atrial appendage ejection fraction and maximum emptying flow velocity (r = 0.67, P = 0,01; r = 0.58, P < 0,001, respectively). There was also significant correlation between systolic pulmonary venous flow velocity time integral and left atrial appendage ejection fraction (r = 0.66, P = 0.001). When normals were excluded from analysis, all the correlations were still significant. We concluded that left atrial appendage is a contractile structure, and that systolic pulmonary venous flow velocity is influenced by left atrial appendage dysfunction. Therefore left atrial appendage function needs to be considered when interpreting Doppler transmitral and systolic pulmonary venous flow patterns.

Adult↗
PubMed1975

Left atrial transport function in myocardial infarction. Importance of its booster pump function.

After myocardial infarction (MI), left ventricular (LV) end-diastolic pressure (EDP) is higher than mean pulmonary artery wedge pressure because of powerful atrial contraction. To evaluate the significane of atrial contraction to left ventricular function we studied 10 control (C) patients without cardiac disease and 17 patients from three to six weeks after acute myocardial infarction. Cardiac catheterization with simultaneous left ventricular diastolic pressure (DP) and left ventricular cineangiograms were obtained. Left ventricular volumes and pressure were (mean +/- SD): (SEE ARTICLE). Although left ventricular stroke volume was lower in the patients with myocardial infarction than in the control subjects (46 versus 56 ml/m2), atrial contraction contributed more to left ventricular filling during diastole (which is the same as left ventricular stroke volume) in the patients with myocardial infarction than in the controls (16 versus 10 ml/m2). The average atrial contribution to left ventricular end-diastolic volume was 11.9 per cent (C), 15.4 per cent (MI); to left ventricular end-diastolic pressure 20 per cent (C), 38.7 per cent (MI); and to left ventricular stroke volume 21.7 per cent (C), 35.1 per cent (MI). Atrial contribution to left ventricular stroke volume was 56 per cent in patients with a cardiac index less than or equal to 2.0 liters/min/m2 and 31 per cent in those with a cardiac index greater than 2 liters/min/m2 (p less than 0.01). Atrial contraction contributed 35 per cent to left ventricular stroke volume in patients with normal end-diastolic volume and in those with increased end-diastolic volume and 10 per cent to end-diastolic volume in patients with increased end-diastolic volume (p less than 0.001). In patients with myocardial infarction, atrial contraction made a large contribution to left ventricular filling and stroke volume irrespective of the type of left ventricular functional derangement that was present. The "booster pump" function of the atrium cannot be ignored in assessing left ventricular performance.

Adolescent↗
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↗
PubMedDate not supplied

Left atrial mechanical function in the healthy elderly: new insights from a combined assessment of changes in atrial volume and transmitral flow velocity.

To assess left atrial mechanical function in the elderly, 35 old (age > 70 years) and 18 sex-matched young (age < 50 years) healthy subjects were studied. Transmitral flow velocities were recorded with pulsed Doppler echocardiography. Left atrial volumes were measured echocardiographically at mitral valve opening (maximal) and closure (minimal) and at onset of atrial systole (P wave of the electrocardiogram) according to the biplane area-length method. Left atrial passive emptying was assessed with the passive emptying volume (maximal-volume at onset of atrial systole) and fraction (passive emptying volume/maximal). Left atrial active emptying was assessed with the active emptying volume (volume at onset of atrial systole-minimal) and fraction (active emptying volume/volume at onset of atrial systole) and with left atrial ejection force = 0.5.blood density.volume at onset of atrial systole.active emptying fraction.(A velocity)2/A integral. Left atrial volumes were greater in old compared with young subjects (maximal: 31 +/- 10 cm3/m2 vs 24 +/- 8 cm3/m2, p = 0.02; at onset of atrial systole: 23 +/- 8 cm3/m2 vs 15 +/- 5 cm3/m2, p = 0.0002; minimal: 13 +/- 5 cm3/m2 vs 9 +/- 4 cm3/m2, p = 0.001). Passive emptying volume and fraction were lower (7.8 +/- 1.7 cm3/m2 vs 9.2 +/- 3.2 cm3/m2 [p = 0.04] and 26.4% +/- 9.8% vs 37.9% +/- 11.2% [p = 0.003], respectively), whereas atrial ejection force and active emptying volume were greater in old compared with young subjects (6.8 +/- 3.3 kdynes/m2 vs 4.2 +/- 2.8 kdynes/m2 [p = 0.007] and 9.2 +/- 4.1 cm3/m2 vs 5.7 +/- 2.9 cm3/m2 [p = 0.002], respectively). The active emptying fraction was similar in the two groups (39.7% +/- 11% vs 38.4% +/- 13%; difference not significant). Thus advanced age is associated with depressed left atrial passive emptying function and increased left atrial volume. Left atrial dilation contributes to an increase in atrial ejection force and the amount of blood ejected during left atrial systole and may represent an important compensatory mechanism in this age population.

Adult↗
PubMed1997

[Echocardiographic factors predicting the maintenance of sinus rhythm one year after cardioversion for non-valvular atrial arrhythmias].

Echocardiographic factors predictive of the maintenance of sinus rhythm after successful cardioversion were investigated in 94 patients with non-valvular atrial arrhythmias of recent onset. Seventy-five patients with atrial fibrillation and 19 with atrial flutter admitted for reduction of their arrhythmias underwent transthoracic and transoesophageal echocardiography. After excluding a thrombus in the left atrial appendage or checking that it had disappeared (5 patients), and electrical (n = 74) or pharmacological (n = 20) cardioversion was successfully performed. The maintenance of sinus rhythm (n = 44) or recurrence of arrhythmia (n = 50) were controlled every 3 months for one year. The mean value of the peak positive blood flow in the left atrial appendage was 38 +/- 20 cm/s for the whole group. It was not possible to identify an echocardiographic parameter predictive of maintenance of sinus rhythm at one year either in the whole group or in the subgroups with atrial flutter or atrial fibrillation. In the group in atrial flutter, the mean value of the peak positive blood flow in the left atrial appendage was significantly greater than in the group with atrial fibrillation: 49 +/- 22 cm/s vs 35 +/- 18 cm/s, respectively; p < 0.05. The peak of positive flow in the left atrial appendage was statistically related to indirect parameters of left atrial function and of left ventricular function in the group with atrial fibrillation but only with parameters of left ventricular function in the smaller group with atrial flutter.

Aged↗
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↗
PubMed2000

[Restoration of the left atrial mechanical function after successful electrical cardioversion].

Some papers indicate that restoration of the left atrial mechanical function (LAMF) can be delayed to even 7 days after successful electrical cardioversion. The goals of the paper include the estimation of delay in restoration of LAMF and factors that influence it. 75 patients (53 males and 22 females, av. age 56.5 +/- 10.8) after elective electrical cardioversion underwent daily echocardiography to determine LAMF, taking A/E ratio > 1/3 as a criterion. The patients were divided into 2 subgroups: G1--with restoration of LAMF < 24 h after cardioversion and G2: the remaining ones. The analysed parameters were: left atrium diameter, rheumatic valvular disease, duration of atrial fibrillation, global and segmental contractility disorders. The data were analysed with ANOVA. The restoration of LAMF < 24 h was found in 53 patients; on the 2nd day in 6 patients, on the 3rd-8th day in 14 patients. In 2 patients no LAMF could be found on the 14th day after cardioversion. Failure to restore LAMF on the cardioversion day was related to: left atrium enlargement, rheumatic valvular disease, duration of atrial fibrillation > 14 days and contractility disorders.

Atrial Fibrillation↗
PubMed1996

[Left atrial contractility function in hypertension].

UNLABELLED: The purpose of this study was the assessment of the left systolic atrial function (LSAF) in 45 hypertensive subjects (HS) with left ventricular hypertrophy (LVH). (LV mass index) (LVMI) (> 134 g/m2 for men, > 110 g/m2 for women) and in 32 normal subjects (NS). The both groups were matched for age, body surface, heart rate and LV fractional shortening. Left atrial volume (LAV) was calculated by the formula: LAV = 8 A1 x A2/3 pi l in which A1 is the area of the four-chamber view, A2 is the area of the two-chamber view and L is common length in the two views. The atrial function contractility was evaluated by the following parameters: 1. LA stroke volume (LASV) = LAV - LAMV where LAV is the volume before atrial systole and LAMV is the LA minimal volume. 2. LA ejection fraction (LAEF) = LASV/LAV. 3. Atrial ejection force (AEF) = peak A/MOA in which peak A wave is the maximal late diastolic velocity and MOA is the mitral orifice area. 4. Atrial transport (AT) = A/M in which M area is under the mitral velocity curve and A-area under the late diastolic velocity curved assessed by Doppler echo. [table: see text] Thus all above parameters are significantly increased in HS. In HS, LASV is correlated to LAV (r = 0.84; p < 0.001) and to LVMI (r = 0.32; p < 0.05). LAEF is correlated to peak A (r = 0.90; p < 0.001) and LVMI (r = 0.34; p < 0.05). CONCLUSIONS: In HS with LVH in comparison with N, the increase of the LA contractility is considered to be urged by the increase of LAV (Frank-Starling's law). These data could be explained by the less distensibility of LV chamber in relation to LVH.

Adolescent↗
PubMed1997

Left atrial appendage function during DDD and VVI pacing.

OBJECTIVE: To examine, using transoesophageal echocardiography, the possible disturbances of left atrial appendage function during VVI and DDD pacing in patients with a normal atrium paced with a dual chamber system. DESIGN: Randomised controlled trial. SETTING: Tertiary care centre. PATIENTS: 22 patients (mean age 68 (SD 6) years) who had been paced with dual chamber pacemakers for at least six months. Exclusion criteria were valvar disease, cardiomyopathy, hypertension, and diabetes mellitus. INTERVENTIONS: All patients underwent a transoesophageal echocardiographic evaluation of left atrial appendage function under DDD and VVI modes in random order. Measurements were made after at least two months' pacing in each mode. MAIN OUTCOME MEASURES: Echocardiographic indices of left atrial appendage flow under both pacing modes. RESULTS: All 22 patients had higher emptying and filling flow velocities under DDD than under VVI mode. The filling and emptying flow velocity integrals were also significantly higher under DDD mode (P < 0.001, P = 0.019). CONCLUSIONS: Left atrial appendage function, as reflected in indices of emptying and filling assessed by transoesophageal echocardiography, is significantly different with DDD than with VVI pacing. This may explain the higher incidence of thromboembolic episodes in patients paced under VVI mode.

Aged↗
PubMed2000

Transesophageal echocardiography assessment of left atrial appendage function in untreated systemic hypertensive patients in sinus rhythm.

To assess left atrial appendage (LAA) function in hypertensive patients without treatment, transesophageal echocardiography (TEE) was performed in 46 hypertensive patients in sinus rhythm, aged 40 to 55 years, and in 16 control subjects (group I) without cardiovascular disease, aged 41 to 54 years. The hypertensive patients were divided into 2 groups according to left ventricular (LV) systolic function: group II, the group with normal LV systolic function (ejection fraction 0.63 +/- 0.08), and group III, the group with LV systolic dysfunction (ejection fraction 0.39 +/- 0.05). The LAA late emptying velocities (EVs) were significantly reduced in the hypertensive subgroups compared with the control group (P <.001), but no significant difference in the LAAEV was found between groups II and III. The LAAEV in the hypertensive patients had a significant negative correlation with diastolic blood pressure, systolic blood pressure, and left atrial (LA) diameter. The maximal LAA areas were significantly larger in the hypertensive subgroups than in the control group (P <.05). No significant difference in LAA maximal area existed between groups II and III. The maximal LAA area in the hypertensive patients had a significant positive correlation with diastolic blood pressure, systolic blood pressure, and LA diameter, but a significant negative correlation with LV ejection fraction. With TEE, LA spontaneous echocardiographic contrast (SEC) was present in 6 (43%) of 14 patients in group III (P <.01) and in 7 (22%) of 32 patients in group II (P <.05). No significant difference in the occurrence of LASEC was found between groups II and III. Left atrial appendage thrombi by TEE were observed in 4 (29%) of 14 patients in group III (P <.05) and in 4 (13%) of 32 patients in group II (P = not significant). No significant difference in the occurrence of LAA thrombus existed between groups II and III. In conclusion, in patients with untreated hypertension, marked elevation of afterload imposed on the left atrium may involve both the left atrium and the LAA, resulting in impairment of LAA function. This condition may worsen with subsequent occurrence of SEC and later, thrombus formation. Therefore assessment of LAA function may be important even in the hypertensive patient in sinus rhythm.

Adult↗
PubMed1993

Left atrial appendage smoke-like echo in dilated cardiomyopathy: its clinical significance and relation to left atrial appendage function.

To elucidate the clinical significance and pathogenesis of left atrial appendage smoke-like echo in dilated cardiomyopathy (DCM), clinical history and transesophageal echocardiographic assessment of left atrial appendage (LAA) anatomy and function were studied in 18 DCM patients with smoke-like echo (SE), 34 patients with DCM but no smoke-like echo and in 14 age-matched normal subjects. Patients with SE had a larger left atrial appendage area, a lower peak LAA systolic flow velocity (PLAAV), a greater incidence of atrial fibrillation, with both left atrial appendage thrombi and a history of arterial embolic episodes, than did patients without SE. Patients in sinus rhythm with SE had a minimal LAA area (5.0 +/- 3.0 cm2) larger than that in the no SE group (3.0 +/- 1.6 cm2) (p < 0.05), and LAA ejection fraction (18 +/- 10%) and PLAAV (24 +/- 9 cm/sec) less than that in the no SE group (40 +/- 11% and 39 +/- 16 cm/sec, respectively) (P < 0.05). Patients with atrial fibrillation (AF) and SE had PLAAV (15 +/- 6 cm/sec) less than that in AF patients without SE (30 +/- 12 cm/sec) (p < 0.05). It is concluded that smoke-like echo in LAA is an indicator of DCM patients with an increased thromboembolic risk usually associated with dilated and poorly contractile LAA.

Adult↗
PubMed1999

Left atrial systolic time interval in hyperthyroidism.

The author noninvasively examined effects of thyroid hormone on left atrial function by using the left atrial systolic time intervals (LASTI) with its parameters as left atrial ejection time (LAET), left atrial preejection period (LAPEP), and LAET/LAPEP, as measured by pulsed Doppler echocardiography. The hyperthyroid (HTH) and normal control (NC) groups consisted of 21 and 25 subjects, respectively. He also considered serum triiodothyronine (T3) concentrations, age, heart rate, systolic blood pressure, left ventricular preload, afterload, contractility, diastolic function, P wave duration, PR interval, and left ventricular preejection period (LVPEP) as factors that might influence LASTI. LAET, LAET/LAPEP, and LVPEP in the HTH group were significantly shorter than in the NC group. LAET showed no significance with serum T3 concentration, but did with LVPEP in partial correlation analysis. These results demonstrated that a short LAET in the hyperthyroid state is controlled by a rapid rise in the left ventricular pressure.

Adult↗
PubMed1993

Preload dependency of left atrial pump function in hypertrophic cardiomyopathy.

In our previous study, we reported that the left atrial contribution to left ventricular filling was decreased to a greater extent in patients with hypertrophic cardiomyopathy than in those with myocardial infarction or normal subjects during lower body negative pressure (LBNP)-induced preload reduction. To clarify the factors responsible for this difference in response, we examined changes in left atrial hemodynamic and M-mode echocardiographic indices during LBNP in patients with hypertrophic cardiomyopathy and myocardial infarction. The same degree of decrease in left atrial preload and afterload was found in both groups. Moreover, we detected no change in the left atrial fractional shortening during left atrial systole (%LAFS) in patients with hypertrophic cardiomyopathy, in contrast to a significant increase found in patients with myocardial infarction. These results showed that the greater decrease in the left atrial contribution in hypertrophic cardiomyopathy during LBNP could not result from differences in changes in left atrial preload or afterload, suggesting that it may be closely related to limitations in the compensatory augmentation of left atrial contractility.

Atrial Function, Left↗