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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↗
PubMed1986

Radionuclide left ventricular function curve during atrial pacing in normal subjects and in patients with coronary artery disease.

We used radionuclide angiography during right atrial pacing to assess left ventricular function in 7 normal subjects and 20 patients with coronary artery disease. A left ventricular function curve relating stroke volume to end-diastolic volume was plotted for each patient. The normal pacing ventricular function curve was a straight line passing through the origin of axes. The pacing ventricular function curve was abnormal in 18 of the 20 patients with coronary artery disease, and three different shaped curves were obtained, reflecting decreased contractile force for the same end-diastolic volume during ischemia. Cardiac output and blood pressure do not change during atrial pacing, thus the Frank-Starling relationship is evaluated by this method during almost experimentally controlled conditions. Relating stroke volume to end-diastolic volume, and not end-diastolic pressure, distinguishes between overall left ventricular systolic function and left ventricular compliance.

Adult↗
PubMed2000

Left ventricular function, cardiac dysrhythmias, atrial activation, and volumes in nondipper hypertensive individuals with left ventricular hypertrophy.

BACKGROUND: Arrhythmic patterns and left ventricular geometric adaptations to pressure overload were investigated in 76 patients with untreated borderline-to-moderate sustained essential hypertension studied by 2-dimensional and M-mode echocardiography, 12-lead, Holter, and signal-averaged electrocardiography, and ambulatory blood pressure monitoring. METHODS AND RESULTS: Sixty-two age- and sex-matched normal adults were chosen for data comparison. Hypertrophic hypertensive patients were subdivided into 2 subgroups: 44 patients with nocturnal blood pressure reduction (dippers) and 32 patients without it (nondippers). Common afterload and diastolic function indexes were found to be lower in combined nondipper and dipper groups, but only fractional shortening decreased in nondippers. The number of premature atrial and ventricular contractions per hour was high in dippers and nondippers, with no statistically significant differences between them; atrial and ventricular complex dysrhythmias were similar. Signal-averaged electrocardiography showed a prolonged P-wave duration in dipper and nondipper patients with high atrial volumes but no late ventricular potentials and no difference in quantitative P-wave analysis. Left atrial volumes, P-wave duration, and premature atrial contractions were found to be positively linked to left ventricular hypertrophy. In nondipper patients a linear correlation was observed between left atrial volume and P-wave duration, although supraventricular ectopic activity was connected to left atrial volume enlargement both in dipper and nondipper patients. CONCLUSIONS: These data suggest that the nondipper pattern is not linked to a worse arrhythmogenic substrate; only atrial volume increase may be related to significant supraventricular activity and prolonged atrial activation in nondipper patients, but late ventricular potentials are uncommon in hypertrophic hypertensive patients.

Arrhythmias, Cardiac↗
PubMed2002

Atrial mechanical performance after internal and external cardioversion of atrial fibrillation: an echocardiographic study.

OBJECTIVES: To compare the time course of resumption of mechanical performance of the left and right atrium after the novel method of internal low-energy cardioversion (CV) and conventional external CV of atrial fibrillation (AF). BACKGROUND: Right atrial performance has been shown to normalize before the left atrium after external CV. However, no data on atrial function after internal CV are available. PATIENTS AND INTERVENTIONS: Sixty-three patients with chronic AF were randomized to participate in either external or internal CV. MEASUREMENTS: Echocardiographic examinations were carried out before as well as immediately after CV (day 0), and at days 1, 7, and 28 thereafter for the determination of cardiac dimensions, volumes, and transvalvular flow patterns. RESULTS: After randomized internal CV or external CV, stable sinus rhythm was restored in 59 patients. Irrespective of the mode of CV, the right atrium resumed its mechanical function immediately after CV, whereas the left atrium was stunned beyond day 7. The mode of CV, internal or external, had no influence on the recovery of atrial mechanical function. CONCLUSIONS: The right atrium resumes its normal function immediately after internal as well as external CV, whereas left atrium function is delayed. In contrast to the assumption that low-energy internal CV would impact less on atrial mechanical recovery, the type of method of CV used has no effect on such recovery.

Aged↗
PubMed1996

Right and left atrial phasic volumetric function in mildly symptomatic dilated and hypertrophic cardiomyopathy: cine MR imaging assessment.

PURPOSE: To characterize biatrial phasic volumetric function in dilated and hypertrophic cardiomyopathy with cine magnetic resonance (MR) imaging. MATERIALS AND METHODS: Eight patients with dilated cardiomyopathy (mean age, 47 years), eight with hypertrophic cardiomyopathy (mean age, 39 years), and eight healthy subjects (mean age, 41 years) underwent cardiac-gated long-axis cine MR imaging of both atria. RESULTS: Left atrial minimum volume averaged 94 mL +/- 37 (standard deviation) in dilated cardiomyopathy, 86 mL +/- 40 in hypertrophic cardiomyopathy, and 51 mL +/- 14 in control subjects (P = .04). Left atrial ejection fraction averaged 16% +/- 6 in dilated cardiomyopathy, 19% +/- 12 in hypertrophic cardiomyopathy, and 28% +/- 7 in control subjects (P = .03). Right atrial minimum volume and ejection fraction were not altered in either form of cardiomyopathy. The normalized filling and emptying rates of either atrium were decreased in both forms of cardiomyopathy. CONCLUSION: In mildly symptomatic dilated and hypertrophic cardiomyopathy, and left atrium is enlarged and its relative cyclic volume changes are reduced. The right atrium is of normal size, but its reservoir function is compromised particularly in dilated cardiomyopathy. Three-dimensional volume measurements with cine MR imaging enable the exposure of altered atrial volumetric function.

Adult↗
PubMed2000

[Non-invasive evaluation of the hemodynamic profile in patients with heart failure: estimation of left atrial pressure].

The management of patients with heart failure requires an accurate and non-invasive estimation of left ventricular filling pressures. This is essential in order to optimize unloading treatment, interpret equivocal symptoms, assess disease severity (and prognosis), and follow up the hemodynamic effect of long-term treatments. Since Doppler technique was implemented, several non-invasive methods to estimate left ventricular filling pressures were developed. Among these, a method based on the calculation of the left ventricular-atrial pressure gradient and its subtraction from systolic arterial blood pressure can be used in patients with significant mitral regurgitation and well-defined continuous wave Doppler signal of the regurgitant flow. Mitral and pulmonary venous flow velocities, as assessed by pulsed Doppler, are closely related to left atrial pressures, and several derived indices can be used to qualitatively estimate left ventricular filling pressures in patients with heart failure due to left ventricular systolic dysfunction who are in sinus rhythm. Furthermore, the combination of these indices in multivariable equations can improve this relationship and allows for a quantitative estimation of filling pressures, even in patients with significant mitral regurgitation and atrial fibrillation. There are, however, several groups of patients with heart failure in whom pulsed Doppler of mitral and pulmonary venous flow provides limited hemodynamic information. These include those with a) sinus tachycardia and/or prolonged P-R interval; b) normal left ventricular systolic function (and "pure" diastolic heart failure); c) primarily abnormal left atrial dysfunction (such as patients who had undergone heart transplantation), and d) technically inadequate Doppler recordings of pulmonary venous flow. To assess left ventricular filling pressures in these patients, two new methods which combine pulsed Doppler mitral flow indices with load-independent indices of left ventricular relaxation (either early diastolic velocity of mitral annulus, as assessed by tissue Doppler, or propagation velocity of mitral inflow, as assessed by color M-mode) can be used.

Atrial Function, Left↗
PubMed1995

Quantification of the voltage-response relationship between punctate and field electrical stimulation and the function of isolated rat left atria and papillary muscles.

The effects of varying the electrical stimulation voltage on the noradrenergic tone and systolic and diastolic cardiac function of isolated rat cardiac preparations is unknown. If a wide range of voltages substantially alters the basal noradrerengic tone of isolated cardiac preparations, highly variable responses may complicate the interpretation of the cardiac effects of interventions, such as drugs or toxins. This study was designed to determine whether field or punctate electrode stimulation altered systolic and diastolic cardiac function of isolated rat atrial and ventricular muscle preparations through a beta-adrenergic receptor-mediated mechanism. Isolated left atria and right ventricular papillary muscles from adult Sprague-Dawley rats were stimulated to contract isometrically in Krebs bicarbonate buffer (30 degrees C, pH 7.4, 0.5 Hz). Cardiac muscle function was assessed by determining cardiac contractility (dF/dt), relaxation (80% relaxation time), and muscle stiffness (changes in resting force). Muscles were electrically stimulated to contract using either punctate or field electrodes. Basal values of cardiac function were determined at threshold voltages, and voltage was increased in stepwise fashion, over a wide range, to obtain a voltage response-relation to cardiac function. In left atrial preparations, both punctate and field electrical stimulation caused a 200% increase in cardiac contractility. The greatest changes in contractility occurred at near threshold voltages (less than 5 volts for punctate and 19 volts for field stimulation). The voltage-dependent increases in cardiac contractility were attenuated or abolished by pretreatment with atenolol (10 micromol/L; selective beta 1-antagonist) or reserpine (5 mg/kg i.p., 24 hr before euthanasia). In contrast to left atrial preparations, neither field or punctate electrical stimulation had any effect on the cardiac contractility of papillary muscle preparations. Neither field or punctate electrical stimulation had any effect on cardiac relaxation (80% relaxation time) or muscle stiffness (changes in resting force) of left atrial or papillary muscle preparations. This study demonstrates that punctate and field electrical stimulation can significantly increase cardiac contractility of rat left atrial preparations at near threshold voltages by increasing noradrenergic tone. Thus, control of the voltage range may be required to reduce variation in cardiac function of isolated rat left atrial preparations.

Animals↗
PubMed1988

A mathematical model of left ventricular function in atrial fibrillation.

Sixty patients with atrial fibrillation (AF) have been studied with Doppler ultrasound to establish the relationship between the duration of R-R intervals and subsequent left ventricular stroke outputs, assessed as stroke distance. Using multiple regression analysis, most of the beat-to-beat variation of stroke distance could be explained in terms of the two preceding R-R intervals (Mean R = 0.82). The relative contribution of these two intervals to the variation of stroke distance was assessed in each patient. In all patients there was a positive correlation between stroke distance and the preceding R-R interval, largely due to the influence of this interval on diastolic filling or preload. In all but one patient the correlation with the second previous R-R interval was negative, the mechanism being changing contractility due to operation of the force-frequency effect. On average, 58% of the variance in stroke distance could be explained by alteration of the previous R-R interval and 10% by alteration of the second previous R-R interval. The relative contribution of the previous R-R interval (preload) falls as left ventricular function declines, and also as mean ventricular rate rises. However, there is a wide individual variation in the pattern of left ventricular function, which may be represented graphically as the haemodynamic profile.

Aged↗
PubMed1984

Left ventricular function during atrial pacing: a radionuclide angiographic study.

Multigated radionuclide angiography was performed at rest and during atrial pacing in 10 normal subjects. Left ventricular volumes in diastole and systole were measured by total counts in the region of interest of the left ventricle. Stroke volume, cardiac output, ejection fraction, and rates of ejection for each heart rate were calculated. As heart rate increased, there was a gradual decrease in end-diastolic, end-systolic, and stroke volumes without a significant change in cardiac output and ejection fraction. Ejection fraction rate increased and the uncorrected ejection rate decreased with the increase in heart rate. The normal response to tachycardia induced by atrial pacing was a decrease in ventricular volumes without a change in ejection fraction or cardiac output.

Adult↗
PubMed1985

Furosemide during sustained left atrial hypertension in functionally anephric dogs: intravascular and extravascular pulmonary fluid volumes. V.

The response of intravascular (PBV) and extravascular (EVLW) pulmonary fluid volume was examined using double-indicator techniques (thermal-green dye) in 11 open-chest anesthetized dogs during the production of sustained left atrial (LA) hypertension by a LA balloon over a period of 195 min. In 6 of these animals data were also acquired after the intravenous administration of furosemide (1 mg/kg). The renal effects of the diuretic were blocked by tying off the ureters and the vascular supply of both kidneys. Left atrial pressure (N = 11) was abruptly increased from 2.2 +/- 2.1 mm Hg to 30.2 +/- 4.0 mm Hg (P less than 0.01) and maintained at that level for 120 min. Data were obtained prior to pressure elevation, immediately upon pressure elevation, and then every 60 min for a total of 120 min. At that point EVLW had increased (8.1 +/- 0.8 cc/kg at control to 21.7 +/- 2.0 cc/kg at 120 min, P less than 0.001), as had PBV (6.2 +/- 2.1 cc/kg to 9.1 +/- 3.1 cc/kg P less than 0.01). After furosemide injection (N = 6), LA pressure declined (mean peak reduction of approximately 6 mm Hg at 60-75 min, P less than 0.01), aortic and pulmonary arterial pressure both declined (P less than 0.01). However, EVLW remained unchanged, though PBV decreased significantly (peak decrease at 75 min after furosemide administration of 2.0 +/- 0.4 cc/kg, P less than 0.01). In the untreated dogs, EVLW continued to climb (P less than 0.05 vs treated dogs at 75 min postfurosemide).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1999

Evaluation of left atrial wall elasticity using acoustic microscopy.

Left atrial wall elasticity is one of the important factors regulating left atrial stiffness and functions. The authors evaluated left atrial wall elasticity by measuring the sound speed through the left atrial wall, based on the hypothesis that high elasticity tissues will yield larger sound speed values through the tissue, and examined age-associated changes in left atrial wall elasticity. Left atrium specimens were obtained from 30 normal subjects (age, 15-95 years) at autopsy. An acoustic microscope, operating at 450 MHz, was used to measure the sound speed in the endocardium and the myocardium of the left atrium. The sound speeds in endocardium and myocardium demonstrated significant correlation with age (r = 0.74, p<0.0001 and r = 0.47, p<0.01, respectively). These findings indicate that left atrial wall elasticity increased with advancing age. These changes may lead to deterioration of left atrial compliance and eventual left atrial failure in older subjects.

Adolescent↗
PubMed2002

Left ventricular function in atrial fibrillation during overdrive pacing.

OBJECTIVE: Our purpose was to measure the effect of ventricular pacing in patients with atrial fibrillation (AF) on stroke volume and cardiac output. BACKGROUND: Unceasing variation in cycle length in AF decreases stroke volume and cardiac output. Because ventricular-inhibited pacing after atrioventricular node ablation has been reported to improve left ventricular performance, we tested the hypothesis that overdrive pacing would produce a similar benefit by regularizing cycle length. METHODS AND RESULTS: We studied 18 patients with chronic AF and permanent pacemakers. The aortic time velocity integral (TVI) was measured with continuous-wave Doppler and was used as a surrogate measure of stroke volume (stroke volume = TVI x aortic valve area, and aortic valve area is constant whether in AF or during pacing). For each patient, the linear relation between preceding cycle length and TVI in AF was used to estimate relative stroke volume (TVI compared within each patient) at a preceding cycle length of 666 ms in AF, and a similar comparison between AF and pacing was made at the minimum allowable pacing rate. Relative stroke volume in AF was then compared with relative stroke volume at both the fixed cycle (666 ms) and the minimum allowable rate. During pacing at 666 ms, relative stroke volume increased significantly by 18% (t = 2.8, P =.048), but there was no difference in cardiac output during pacing at the minimum possible rate and the corresponding preceding cycle length in AF. CONCLUSION: Our data suggest that regularization of ventricular rhythm by overdrive pacing in patients with AF only improves stroke volume (and by extension, cardiac output) at pacing rates at the outer limit of and above the normal physiologic range.

Adult↗
PubMed1998

Left atrial "stunning" following radiofrequency catheter ablation of chronic atrial flutter.

OBJECTIVES: This study examined the effect of radiofrequency ablation (RFA) on left atrial (LA) and left atrial appendage (LAA) function in humans with chronic atrial flutter (AFL). BACKGROUND: Atrial stunning and the development of spontaneous echocardiographic contrast (SEC) is a consequence of electrical cardioversion of AFL to sinus rhythm. This phenomenon has been termed "stunning" and is associated with thrombus formation and embolic stroke. Radiofrequency ablation is now considered to be definitive treatment for chronic AFL, but whether this procedure is complicated by LA stunning is unknown. METHODS: Fifteen patients with chronic AFL undergoing curative RFA underwent transesophageal echocardiography to evaluate LA and LAA function and SEC before and immediately, 30 minutes and 3 weeks after RFA. To control for possible direct effects of RFA on atrial function, seven patients undergoing RFA for paroxysmal AFL were also studied. In this group, RF energy was delivered in sinus rhythm and echocardiographic parameters were assessed before and immediately and 30 minutes following RFA. RESULTS: Chronic AFL: Mean arrhythmia duration was 17.2 +/- 13.3 months. Twelve patients (80%) developed SEC following RF energy application and reversion to sinus rhythm. LAA velocities decreased significantly from 54.0 +/- 14.2 cm/s in AFL to 18.0 +/- 7.1 cm/s in sinus rhythm after arrhythmia termination (p < 0.01). These changes persisted for 30 minutes. Following 3 weeks of sustained sinus rhythm, significant improvements in LAA velocities (68.9 +/- 23.6 vs. 18.0 +/- 7.1 cm/s, p < 0.01) and mitral A-wave velocities (49.8 +/- 10.3 vs. 13.4 +/- 11.2 cm/s, p < 0.01) were evident and SEC had resolved in all patients. Paroxysmal AFL: Radiofrequency energy delivered in sinus rhythm had no significant effect on any of the above indexes of LA or LAA function and no patient developed SEC following RFA. CONCLUSIONS: Radiofrequency ablation of chronic AFL is associated with significant LA stunning and the development of SEC. Left atrial stunning is not secondary to the RF energy application itself. Sustained sinus rhythm for 3 weeks leads to resolution of these acute phenomena. Left atrial stunning occurs in the absence of direct current shock or antiarrhythmic drugs, suggesting that its mechanism may be a function of the preceding arrhythmia rather than the mode of reversion.

Atrial Flutter↗
PubMed1995

Left atrial appendage contractile function in atrial fibrillation. Influence of heart rate and cardioversion to sinus rhythm.

BACKGROUND: A high incidence of embolic phenomena is associated with atrial fibrillation (AF) and the left atrial appendage (LAA) is frequently the source of the emboli. Thrombus formation may be due to stasis within the fibrillating and inadequately emptying LAA. Because LAA emptying in AF may be the result of mechanical compression by the adjacent left ventricle, it is possible that left ventricular diastolic filling duration will importantly influence passive emptying of the LAA. We hypothesized that the magnitude of emptying of the LAA in AF is related to the duration of left ventricular diastolic filling which is determined by the ventricular response rate in AF. OBJECTIVE: The objective of our study was to determine the relationship of ventricular response rate in AF to LAA emptying and to assess the influence of sinus rhythm and heart rate on LAA emptying immediately after direct current cardioversion to sinus rhythm. METHODS: To study this, we used transesophageal echocardiography to measure LAA ejection fraction ([LAAmax-LAAmin]/LAAmax x 100%) and evaluated its relationship to left ventricular response rate (VRR) in 26 patients with AF (mean age, 65 +/- 7 [1 SD] years). RESULTS: There was a strong inverse relationship between LAA ejection fraction and VRR in AF (r = -0.73; p < 0.001). LAA ejection fraction during AF was 26 +/- 10%, and immediately after successful cardioversion, it increased to 46 +/- 12% (p < 0.001). However, during sinus rhythm there was no relationship between LAA ejection fraction and VRR (r = 0.06; p = NS) in the subgroup of patients who were successfully converted to sinus rhythm. There were poor relationships between LAA ejection fraction and peak transmitral flow velocity (r = -0.41; p = NS) or pulmonary venous flow velocity (r = -0.03; p = NS) in AF. CONCLUSION: These results indicate that the magnitude of LAA emptying in AF is strongly and inversely influenced by ventricular rate. Direct current cardioversion to sinus rhythm is associated with an increase in the magnitude of LAA emptying that is not influenced by heart rate. The magnitude of LAA emptying may be an important factor in the formation of thromboemboli in AF. The extent to which controlling the VRR in chronic AF will prevent stasis and LAA thrombus formation remains to be determined.

Aged↗
PubMed1992

[Left atrial ejection performance in heart failure as assessed by transesophageal Doppler echocardiography].

To investigate the left atrial ejection performance in heart failure, we observed both the transmitral (TMF) and pulmonary venous flow waves (PVF) by transesophageal Doppler echocardiography in 20 patients with heart failure (16 males, 4 females, 56 +/- 13 years old). In 7 of 20 patients, pulmonary capillary wedge pressures (PC) were also obtained within 72 hours after the transesophageal Doppler echocardiographic examinations. A reversal flow on PVF during atrial systole (atrial backward ejection flow) was observed in all of the 20 patients. Corrected atrial pre-ejection period correlated significantly with PC (r = -0.76, p < 0.05), indicating that the period was shortened in accordance with left atrial Starling's law. This period correlated significantly with both the duration and the time velocity integral of atrial backward flow (r = -0.72, p < 0.005; r = -0.55, p < 0.05, respectively), but not with the atrial ejection time nor with the time velocity integral of atrial systole. These results suggest that in some cases of heart failure, left atrial contractile function is preserved despite the marked augmentation of left atrial afterload, resulting in a decrease of the left atrial forward ejection and an increase of the left atrial backward ejection. Thus, the observations of TMF and PVF by transesophageal Doppler echocardiography are useful for assessing the left atrial ejection performance in patients with heart failure.

Adult↗
PubMed2005

Strain rate imaging for noninvasive functional quantification of the left atrium: comparative studies in controls and patients with atrial fibrillation.

Strain rate (SR) imaging enables quantitative measurement of left ventricular (LV) function independent of cardiac translation. However, whether SR imaging is applicable for detection of left atrial (LA) dysfunction remains unknown. The purpose of this study was to assess the feasibility of measuring LA function by SR imaging, focusing on the effects of aging and LA dilatation during atrial fibrillation (AF). Echocardiographic evaluation including SR imaging was performed in 50 controls (29 males and 21 females; mean age, 41 +/- 14 years) and in 27 patients with AF (15 males and 12 females; mean age, 62 +/- 12 years; 8 with persistent AF and 19 with paroxysmal AF) from 3 apical views and analyzed off-line. Peak SR was measured at each LA segment (septum, lateral, posterior, anterior, and inferior), and mean peak systolic SR (SR-LAs), early diastolic SR (SR-LAe), and late diastolic SR (SR-LAa) were calculated by averaging the results for each segment. LA dimension, peak mitral and pulmonary velocities at late diastole, LA fractional shortening, and atrial filling fraction were calculated as parameters of LA function. Normal values for mean SR-LAs, SR-LAe, and SR-LAa were 3.4 +/- 1.0 s -1 , -3.9 +/- 1.7 s -1 , and -3.1 +/- 1.0 s -1 , respectively, and they were successfully measured in more than 95% of the LA segments. In controls, both mean SR-LAs and mean SR-LAe correlated with age, LA dimension, and early to late diastolic mitral flow velocity ratio. Conversely, mean SR-LAa did not show significant correlation with age or parameters of LA function. In AF patients, mean SR-LAs was correlated inversely with age. The mean SR-LAs was significantly lower in persistent AF patients than in age-matched controls (1.7 +/- 0.8 vs 2.9 +/- 0.9 s -1 ; P < .01). Based on our findings, we conclude that noninvasive quantification of LA function using SR imaging enables evaluation of LA dysfunction due to aging and LA dilatation.

Adult↗
PubMed1996

[Stratification of the thromboembolic risk in patients with non-rheumatic atrial fibrillation: assessment of left atrial dysfunction].

BACKGROUND: Patients with non rheumatic atrial fibrillation (NRAF) have an increased risk for thromboembolic complications. Recent evidence suggests that left atrial appendage function (contraction, filling dynamics) may provide clues to the thrombogenic potential of this structure. The aim of this study was to identify left atrial spontaneous echocontrast and thrombus between patients with NRAF and their relationship with left atrial appendage function. METHODS: Transthoracic (TTE) and biplane or multiplane transesophageal echocardiography (TEE) were performed in 143 patients with chronic NRAF enrolled in the Trieste Area Study on non rheumatic Atrial Fibrillation (TASAF), an ongoing prospective community study with a follow-up period of 2 years. The maximal and minimal areas of the left atrial appendage were measured during three cardiac cycles and the peak emptying and filling velocities profile were obtained by pulsed wave Doppler at the orifice of the left atrial appendage. The left atrium and appendage were inspected for thrombus and spontaneous echocontrast. RESULTS: Left atrial appendage thrombus was present in 37 patients (26%) and spontaneous echocontrast in 60 patients (42%), 45% of patients with spontaneous echocontrast had thrombus. Univariate analysis identified positive correlation of thrombus with duration of atrial fibrillation (p = 0.05), hypertension (p = 0.01), left atrial area (p = 0.005), mitral annular calcification (p = 0.01), left ventricular dysfunction (p = 0.03) and a non significant correlation with the mitral valve prolapse (p = 0.08) in the TTE. The presence of mitral regurgitation did not demonstrate a protective effect (p = 0.73) against thrombosis. The variables of left atrial appendage function identifying a subgroup of patients with increased risk of thrombus formation were: shortening fraction of the area in the horizontal and vertical sections (p = 0.0001 and p = 0.002 respectively), the peak filling and emptying velocity in horizontal (p = 0.0001 equal for both) and vertical sections (p = 0.0001 equal for both). In summary these patients have a larger left atrial maximal area (p = 0.004) and a lower flow velocity profile (p < 0.00001) and more intense spontaneous echocontrast (p < 0.00001) than the others. Spontaneous echocontrast was correlated with left ventricular dysfunction (p = 0.008), left atrial area (p = 0.02) and there was a non-significant correlation with mitral annular calcification (p = 0.09) and lower left ventricular shortening fraction (p = 0.06). Transesophageal echocardiography variables have identified the subgroup of patients with an increased risk of echocontrast formation. This was positively associated with a low flow velocity profile (p = 0.0001), a left atrial appendage low shortening fraction in horizontal section (p = 0.001) and in vertical section (p = 0.05) and a low peak filling velocity in horizontal section (p = 0.003) and in vertical section (p = 0.004) and a low peak emptying velocity in horizontal section (p = 0.003) and in vertical section (p = 0.001). Prophylactic therapy with anticoagulant or antiplatelet agents has little benefits in our experience. CONCLUSIONS: Spontaneous echocontrast and low flow profile velocity (low peak emptying and filling velocity) and increased area of left atrial appendage were strongly associated with left atrial and/or appendage thrombus in patients with NRAF. The assessment of left atrial appendage function by TEE is an important component of the comprehensive evaluation of potentially increased risk of thrombus formation.

Aged↗
PubMed2002

Usefulness of phased-array intracardiac echocardiography for the assessment of left atrial mechanical "stunning" in atrial flutter and comparison with multiplane transesophageal echocardiography(*).

We compared transesophageal and phased-array intracardiac echocardiography (TEE/ICE) for the 2-dimensional and spectral Doppler assessment of left atrial (LA) mechanical function. TEE is commonly used to assess LA body and LA appendage mechanical function in patients who are undergoing radiofrequency ablation of typical atrial flutter. Fifteen patients underwent TEE and ICE imaging before and after ablation of typical atrial flutter. The following parameters were measured: (1) LA appendage emptying velocity and fractional area change, (2) severity of LA spontaneous echo contrast (graded 0 to 4), (3) maximal inflow velocity of the left and right upper pulmonary veins, and (5) maximal mitral valve E- and A-wave inflow velocities in sinus rhythm. Diagnostic quality imaging was achieved in all patients with TEE and ICE. Comparing TEE and ICE, the following absolute values and linear correlation coefficient (R) were obtained: preablation LA appendage emptying velocity: 0.45 +/- 0.21 versus 0.44 +/- 0.21 m/s (r = 0.95, p = <0.001); postablation LA appendage velocity: 0.33 +/- 0.24 versus 0.34 +/- 0.24 m/s (r = 0.97, p <0.001); LA appendage fractional area change: 35.3 +/- 13.7 versus 35.9 +/- 17.1% (r = 0.81, p <0.001); left upper/right upper pulmonary vein inflow velocity: 0.50 +/- 0.17/0.49 +/- 0.18 versus 0.51 +/- 0.17/0.47 +/- 0.20 m/s (r = 0.93/0.90, p <0.001); mitral valve E/A wave: 0.66 +/- 0.14/0.31 +/- 0.14 versus 0.69 +/- 0.17/0.35 +/- 0.23 (r = 0.84/0.97, p <0.002); LA spontaneous echo contrast (pre- and postablation): 1.1 +/- 1.2/1.3 +/- 1.2 versus 1.2 +/- 1.3/1.4 +/- 1.3 (r = 0.92/0.90, p <0.001). No patients were identified with LA appendage thrombus. Thus, TEE and phased-array ICE provided equivalent imaging data with high statistical correlation. ICE may be an imaging alternative to TEE in the evaluation of a "stunned" left atrium.

Adult↗