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PubMed2002

Effect of haemodialysis on left atrial mechanical function in patients with chronic renal failure.

OBJECTIVE: The aim of this study was to investigate the potential effects of haemodialysis on left atrial (LA) mechanical functions in patients with chronic renal failure. METHODS: Thirty-two patients with chronic renal failure (mean age 42.8 +/- 19.6 years) were included in this study. LA volumes were determined echocardiographically at the time of mitral valve opening (maximal,Vmax), at the onset of atrial systole (p wave at the electrocardiography = Vp) and at the mitral valve closure (minimal, Vmin) according to the biplane area-length method in apical 4-chamber and 2-chamber view. All volumes were corrected to the body surface area, and the following left atrial emptying functions were calculated. LA passive emptying volume = Vmax - Vp, LA passive emptying fraction = LA passive emptying volume/Vmax. Conduit volume = LV stroke volume-(Vmax - Vmin), LA active emptying volume = Vp Vmin. LA active emptying fraction = LA active emptying volume/Vp, LA total emptying volume = (Vmax - Vmin), LA total emptying fraction = LA total emptying volume/Vmax. RESULTS: Mean fluid removal was 1,875 +/- 812 milliliter. There was no difference between in the LA passive emptying volume before and after dialysis (10.83 +/- 7.44 vs. 11.47 +/- 7.73 cm3/m2, p > 0.05). Conduit volume (from 15.30 +/- 10.68 to 10.31 +/- 6.83 cm3/m2, p < 0.05), LA active emptying volume (from 12.61 +/- 6.39 to 9.25 +/- 4.40 cm3/m2, p < 0.005), LA total emptying volume (from 23.44 +/- 8.52 to 20.72 +/- 8.58 cm3/m2, p < 0.05), LA maximal volume (from 39.44 +/- 14.07 to 28.89 +/- 11.80 cm3/m2, p < 0.001), LA minimal volume (from 15.99 +/- 9.70 to 8.17 +/- 4.52 cm3/m2, p < 0.001), and the volume at the onset of atrial systole (from 28.61 +/- 10.36 to 17.42 +/- 7.20 cm3/m2, p < 0.001) decreased significantly after the haemodialysis session, whereas LA passive emptying fraction (from 0.27 +/- 0.14 to 0.38 +/- 0.14%, p < 0.001), LA active emptying fraction (from 0.46 +/- 0.18 to 0.53 +/- 0.17%, p < 0.05), LA total emptying fraction (from 0.61 +/- 0.14 to 0.72 +/- 0.09%, p < 0.001) increased significantly after haemodialysis. CONCLUSION: The results of this study suggest that left atrial mechanical functions improve after haemodialysis in patients with chronic renal failure.

Adult↗

PubMed1992

Functional capacity of patients with atrial fibrillation and controlled heart rate before and after cardioversion.

OBJECTIVE: To measure exercise duration (which frequently is diminished by atrial fibrillation) and to compare the gain in exercise duration achieved by heart rate control with the gain after cardioversion. METHODS AND RESULTS: Eighteen patients (10 with structural heart condition and eight with lone atrial fibrillation) did the treadmill exercise stress test using the Bruce protocol. Resting supine heart rate was lowered below 100 beats/min by verapamil (initial exercise stress test). An exercise stress test was then repeated as often as needed to achieve 'heart rate control' (less than 130 beats/min at the end of a 3 min walk at 10 degrees elevation and 2.74 km/h speed). This heart rate control was obtained by gradual increases in verapamil dose. Subsequently, the patients were converted to normal sinus rhythm chemically (seven patients) or electrically (11 patients) and an exercise stress test was repeated. At cardioversion, patients were on antiarrhythmic therapy and verapamil was discontinued in most. All patients had left atrial size measured by echocardiogram before and after cardioversion, and all were followed for four months. Upon achieving controlled heart rate, exercise duration increased in 16 patients (average gain was 164 s). After cardioversion to normal sinus rhythm, exercise duration further increased in 13 cases with an average additional gain of 90 s. The total increase in exercise duration after cardioversion was 254 s. Post cardioversion, all patients with lone atrial fibrillation improved. A decline in exercise performance occurred in four patients with fixed cardiac output. Average gain in exercise duration was independent of drugs used. Left atrial size remained increased post cardioversion (50.4 mm before and 52 mm after). During four months of follow-up, only eight patients could continue on the same medication given for cardioversion. Three patients did not maintain normal sinus rhythm. CONCLUSIONS: Conversion to normal sinus rhythm in patients with atrial fibrillation is associated with improved exercise tolerance except in cases with fixed cardiac output. Restoration of mechanical atrial function appears to be responsible for improved exercise performance following cardioversion.

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PubMed1970

Left atrial booster function in valvular heart disease.

This study was designed to assess atrial booster pump action in valvular heart disease and to dissect booster pump from reservoir-conduit functions. In five patients with aortic stenosis and six with mitral stenosis, sequential atrioventricular (A-V) pacing was instituted during the course of diagnostic cardiac catheterization. Continuous recording of valvular gradient allowed estimation of flow for each cardiac cycle by transposition of the Gorlin formula. Left ventricular ejection time and left ventricular stroke work in aortic stenosis or left ventricular mean systolic pressure in mitral stenosis were also determined. Control observations were recorded during sequential A-V pacing with well-timed atrial systole. Cardiac cycles were then produced with no atrial contraction but undisturbed atrial reservoir function by intermittently interrupting the atrial pacing stimulus during sequential A-V pacing. This intervention significantly reduced valvular gradient, flow, left ventricular ejection time, and left ventricular mean systolic pressure or stroke work. Cardiac cycles were then produced with atrial booster action eliminated by instituting synchronous A-V pacing. The resultant simultaneous contraction of the atrium and ventricle not only eliminated effective atrial systole but also placed atrial systole during the normal period of atrial reservoir function. This also significantly reduced all the hemodynamic measurements. However, comparison of the magnitude of change from these two different pacing interventions showed no greater impairment of hemodynamic state when both booster pump action and reservoir function were impaired than when booster pump action alone was impaired. The study confirms the potential benefit of well placed atrial booster pump action in valvular heart disease in man.

Adolescent↗

PubMed2001

Left atrial systolic function in relation to electrical and mechanical remodeling in a canine model.

Rapid atrial activation causes electrical remodeling that promotes the occurrence and maintenance of atrial fibrillation. The aim of this research was to compare the relationship between mechanical remodeling and atrial electrophysiology. Eight dogs (beagles) were subjected to rapid atrial pacing (AP) at 400 beats/min for 16 days. After a complete recovery of electrical variables and left ventricular function evaluated by echocardiography, they underwent high-rate ventricular pacing (VP) at 240 beats/min of equal duration. In half of them, the study was started by VP and in the other half by AP. Left atrial systolic function was assessed by transesophageal echocardiography. Atrial effective refractory period (AERP) at a basic cycle length of 400 ms decreased significantly after either type of pacing (AP: 115 +/- 17 ms, VP: 136 +/- 22 ms) compared with baseline values (153 +/- 23 ms); the difference between tachycardias was significant too (p < 0.02). Significant increases (p < 0.05) in left atrial dimensions (LA-A) (AP: 2.41 +/- 0.23 cm ,VP: 2. 43 +/- 0. 34 cm vs. basal: 2. 16 +/- 0. 21 cm) indicated atrial dilatation after either type of pacing, the differences between two groups being insignificant. Atrial reversal pulmonary venous flow (AR velocity) decreased in AP (-0.13 +/- 0. 02 m/s) and VP (-0. 17 +/- 0. 04 m/s). The difference was highly significant as compared to basal values (-0.25 +/- 0.05 m/s) and also with respect to both tachycardias (p < 0.01). In both groups, atrial remodeling occurred in a relatively short period of time. The echocardiographic findings suggested that left atrial systolic function was significantly more disturbed in the AP group than in the VP group. Mechanical changes are an important substrate of electrical remodeling, yet the deterioration of electrical variables was more pronounced in AP than in VP.

Animals↗

PubMed2000

Efficacy of single lead VDD pacing in patients with impaired and normal left ventricular function.

Atrial synchronous ventricular pacing seems to be the best pacing mode for patients with advanced AV block and impaired LV function. The long-term follow-up of single lead VDD pacing was studied in 33 patients with impaired LV function and compared to 42 patients with normal LV function. All patients received the same VDD lead and VDDR pacemaker. The lead model with 13-cm AV spacing between the atrial and ventricular electrode was implanted in 89% of the patients. Follow-ups were 1, 3, 6, and 12 months after implantation. The percentage of atrial sensing and the P wave amplitude were determined at each follow-up. Minimal P wave amplitude at implantation was 2.0 +/- 1.4 mV in patients with impaired and 1.7 +/- 0.9 mV with normal LV function (not significant). At the 12-month follow-up, 33 patients with normal and 23 patients with depressed LV function remained paced in the VDD mode. The remaining patients died in five (impaired LV function) and seven cases (normal LV function) or their pacemakers were programmed to the VVI/VVIR pacing mode in four (impaired LV function) and three cases (normal LV function). P wave amplitude did not differ in the two groups (e.g., at month 12: impaired: 1.17 +/- 0.42 mV; normal: 1.09 +/- 0.49 mV). The atrial sensitivity was programmed in most patients to sensitive settings with no differences between the two groups (e.g., at month 12: impaired: 0.13 +/- 0.06 mV; normal: 0.13 +/- 0.05 mV). The diagnostic counters indicated nearly permanent atrial sensing (e.g., at month 12: impaired: 99.3 +/- 2.2%; normal: 99.0 +/- 1.0 mV). In conclusions, single lead VDD pacing restored AV synchronous ventricular pacing in patients with normal and with impaired LV function indicating that it could be an alternative to DDD pacemakers, but not to dual-chamber pacing.

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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↗

PubMed2004

Comparison of left atrial volume and function after linear ablation and after cardioversion for chronic atrial fibrillation.

Several techniques for treatment of atrial fibrillation (AF) have been developed, including the direct placement of radiofrequency for lesions at open heart surgery. Detailed evaluation of left atrial (LA) function has not been performed after these procedures and has not been compared in patients with chronic AF. We compared the atrial function of patients with sustained sinus rhythm (SR) after linear ablation with a group who underwent direct-current cardioversion and a group of normal controls to investigate the measurable deleterious effects, if any, on atrial function after the surgical procedure. Twenty-one consecutive patients who had maintained SR for >6 months after a linear radiofrequency ablation (LRFA) procedure were studied. As control subjects, we examined 33 patients with chronic AF successfully restored to SR by cardioversion who maintained SR for >6 months and 42 age-matched normal subjects. LA function was decreased in both the LRFA and cardioverted AF groups compared with normal controls. The parameters of LA function, atrial fraction, LA ejection fraction, and the A' velocity were lowest in the LRFA group, intermediate in the cardioverted AF group, and highest in the normal controls (LA function: 15.8 +/- 10%, 26 +/- 10%, 33 +/- 7%; p = 0.0001; LA ejection fraction: 31 +13%, 41 +/- 12%, 51 +/- 9%; p = 0.0001; A' velocity: 4.2 +/- 1.4, 7.6 +/- 2.2, 9.5 +/- 1.9 cm/s; p = 0.0001). LA volumes were increased in the LRFA and cardioverted AF groups compared with normals (62.8 +/- 22 vs 70.6 +/- 17 vs 38.7 +/- 9.8 ml; p = 0.0001). Thus, although LA function is restored and maintained after LRFA has been performed during open heart surgery, LRFA use is associated with a measurable decrease in LA function over and above that found after conventional cardioversion.

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PubMed1998

"Stunning" of the left atrium after spontaneous conversion of atrial fibrillation to sinus rhythm: demonstration by transesophageal Doppler techniques in a canine model.

OBJECTIVES: This study compared left atrial and left atrial appendage contraction velocities in sinus rhythm before and after a brief period of atrial fibrillation in a canine model. BACKGROUND: In patients, left atrial appendage contraction velocities measured during sinus rhythm after cardioversion from atrial fibrillation are depressed relative to left atrial appendage emptying velocities measured during atrial fibrillation, suggesting that the left atrial appendage is mechanically "stunned." METHODS: This phenomenon was studied in a canine model of acute (60 min) pacing-induced atrial fibrillation followed by spontaneous reversion to sinus rhythm using epicardial and transesophageal pulsed wave Doppler. Unique features of the model include: 1) comparison of left atrial function postconversion to baseline sinus rhythm rather than to measurements during atrial fibrillation, 2) control of the duration of atrial fibrillation and 3) elimination of the extraneous influences of direct current shock and antiarrhythmic agents, which may independently depress left atrial function. RESULTS: Hemodynamic conditions (heart rate, mean arterial pressure, cardiac output, mean pulmonary artery pressure, mean right atrial pressure and mean left atrial pressure) at baseline, during 60 min of atrial fibrillation and after reversion to sinus rhythm were constant throughout the study period. Peak left atrial contraction velocities (measured from the transmitral flow velocity profile) were significantly (p < 0.02) reduced to 64+/-22% of baseline values upon spontaneous conversion of atrial fibrillation to sinus rhythm and recovered to basal values by 20 min after resumption of sinus rhythm. Peak left atrial appendage contraction velocities were significantly (p < 0.001) reduced to 49+/-24% of baseline values upon spontaneous conversion of atrial fibrillation to sinus rhythm and recovered to basal values by 40 min after reversion to sinus rhythm. CONCLUSIONS: Even brief (60 min) periods of atrial fibrillation in normal canine hearts result in marked depression of global left atrial systolic function and regional left atrial (left atrial appendage) systolic function upon resumption of sinus rhythm. This "mechanical stunning" of left atrial systolic function appears to be more profound and of longer duration for the left atrial appendage compared with the left atrium as a whole, which may predispose the appendage to blood stasis and thrombus formation. Chronic models of atrial fibrillation need to be developed to examine the impact of longer periods of atrial fibrillation upon the magnitude and duration of postconversion left atrial "stunning."

Animals↗

PubMed2000

Clinical and echocardiographic characteristics of left atrial spontaneous echo contrast in sinus rhythm.

OBJECTIVES: In this study we attempt to define the clinical and echocardiographic characteristics of patients with left atrial spontaneous echo contrast (LASEC) in sinus rhythm (NSR). BACKGROUND: Left atrial spontaneous echo contrast in atrial fibrillation (AF) is associated with increased risk of thromboembolism. Little is known about its significance in NSR. METHODS: We reviewed reports of 1,288 transesophageal echocardiogram (TEE) studies done with a 5 MHz probe. Patients with swirling LASEC who were in NSR during TEE were analyzed. We compared them with a control group of 45 age matched patients selected to have NSR, left atrium (LA) > 4.0 cm but no SEC. RESULTS: Spontaneous echo contrast in NSR was noted in 24 patients (2%) and formed our study group. All patients with SEC had enlarged LA, mean 5.6 cm +/- 0.6 cm. There was a higher prevalence of cerebrovascular accident (CVA) in patients with SEC when compared with controls with no SEC, 83% versus 56%, p = 0.02. Patients with SEC had larger LA, 5.6 versus 4.9 cm, p < 0.0001 and lower mean peak left atrial appendage emptying velocity (LAAEV), 38 versus 56 cm/s, p = 0.001. Thirteen percent of patients with SEC had LA thrombus as compared with none in the control group, p = 0.02. By multivariate analysis, SEC in NSR was found to be associated with CVA, larger LA size and decreased mean LAAEV. Even after adjusting for LA size, patients with SEC had a higher prevalence of CVA than controls, p = 0.03. CONCLUSIONS: Spontaneous echo contrast in NSR occurs in patients with significantly dilated LA and depressed atrial function. Left atrial thrombus is noted in 13% of such patients despite NSR. Spontaneous echo contrast in NSR is associated with a higher prevalence of CVA. Further, SEC is found to be an independent and more powerful correlate of CVA than reduced LAAEV or atrial size. These data indicate that LASEC in NSR is a prothombotic condition.

Aged↗

PubMedDate not supplied

Two-dimensional echocardiographic assessment of the feline left atrium.

Atrial size determined by echocardiography provides a surrogate measure of the hemodynamic burden of cardiac disease. Linear atrial dimensions often are indexed to aortic diameter. Whereas quantitative variables obtained from healthy cats, using 2-dimensional echocardiography (2DE), have been reported, indices from 2DE, have not. Using 2DE and M-mode echocardiography, we calculated indices of left atrial size and a single index of atrial function, left atrial fractional shortening, in 17 healthy cats. Specifically, left atrial dimensions from short- and long-axis 2DE planes were indexed to aortic diameter and also to end-diastolic left ventricular dimension. Additionally, left atrial circumference and area were indexed to aortic circumference and area, respectively. The same variables were obtained from 20 cats with hypertrophic cardiomyopathy (HCM), so that agreement between 2DE indices and indices from M-mode echocardiography could be evaluated over a clinically relevant range of atrial sizes. Atrial dimensions and indices of atrial size from cats with HCM exceeded those of healthy cats. Left atrial dimension from 2D short-axis images indexed to aortic diameter generally was less than the analogous index obtained from M-mode (mean bias, [95% limits of agreement] -0.13, [-0.42, 0.17]). Left atrial dimension from 2D long-axis images indexed to aortic diameter generally was greater than the index obtained from M-mode (0.15, [-0.28, 0.58]). We conclude that ratios of left atrial size and aortic diameter, from 2DE and M-mode echocardiography, are not interchangeable. Normative data that may serve as reference intervals for 2DE assessment of atrial size are presented.

Animals↗

PubMed1998

Right ventricular function in orthotopic total atrioventricular heart transplantation.

BACKGROUND: Total orthotopic heart transplantation was recently introduced into clinical practice as an alternative technique of orthotopic heart transplantation, adding bicaval and left and right pulmonary vein anastomoses to pulmonary artery and ascending aorta connection (total technique). The conventional technique (ventricular transplantation with atrioplasty) is compared with the total technique with particular emphasis on right ventricular performance. METHODS: Forty-eight mongrel dogs (23 to 31 kg) were used for 12 total and 12 standard orthotopic heart transplantations. Right ventricular (RV) function and atrial systole were analyzed with the use of micromanometry, sonomicrometry, and ultrasonic flow probes (preload-independent RV recruitable stroke work, RVPRSW). Fourier analysis was used to calculate RV power and pulmonary vascular impedance. RESULTS: There was no significant difference in cardiac ischemic and bypass times between the two groups. After transplantation, sinus rhythm was preserved after all total transplantations and after only one standard transplantation; no significant hemodynamic differences were observed. RVPRSW in the total group was conserved after transplantation; however, RVPRSW decreased by 39% (+/-8, p < .05) in the standard group. There was also a significant decrease in the rate of RV filling in the standard group after transplantation, suggesting decreased right atrial function. Pulmonary vascular impedance and RV power output were not significantly different after transplantation between the two groups. CONCLUSIONS: Total atrioventricular transplantation is a feasible alternative and conserves normal sinus rhythm. Ischemic and bypass times were not significantly different when the superior vena cava anastomosis is performed last after the release of the aortic cross-clamp. The insignificant decrease in the rate of RV filling with the use of the total technique suggests conserved RV diastolic function after transplantation with less decreased RV function in the total group.

Animals↗

PubMed2004

Color Doppler tissue imaging to evaluate left atrial appendage function in patients with mitral stenosis in sinus rhythm.

Two-dimensional color Doppler tissue imaging (CDTI) has so far been used, in general, to evaluate ventricular function. In this study, the left atrial appendage (LAA) tissue velocity was measured by CDTI. LAA function in 38 patients with mitral stenosis in sinus rhythm (SR) and 19 healthy subjects undergoing transesophageal echocardiography were examined by CDTI. Systolic tissue appendage velocity (SaV, m/s) was measured at the tip of the LAA in the basal short-axis view. LAA emptying (LAAEV) and filling (LAAFV) velocities (m/s) were also recorded 1 cm below the orifice of the appendage. LAA ejection fraction was also measured. In addition, two-dimensional imaging was used to determine the presence of thrombus and/or spontaneous echo contrast (SEC). Patients with mitral stenosis in SR had significantly decreased LAAEV, LAAFV, SaV, and LAA ejection fraction compared to controls (0.34 +/- 0.15 vs 0.72 +/- 0.17, 0.37 +/- 0.13 vs 0.63 +/- 0.19, 0.050 +/- 0.015 vs 0.071 +/- 0.093, and 39 +/- 14% vs 69 +/- 13%, respectively, P < 0.001, P < 0.001, P < 0.001, and P < 0.001). Among the patients with mitral stenosis in SR, 10 patients had SEC and one had LAA thrombus. Compared with patients without SEC, patients with SEC had decreased LAAEV, LAAFV, SaV, and LAA ejection fraction (0.24 +/- 0.05 vs 0.37 +/- 0.16, 0.29 +/- 0.05 vs 0.39 +/- 0.14, 0.039 +/- 0.087 vs 0.055 +/- 0.015, and 28 +/- 14% vs 43 +/- 12%, respectively, P = 0.01, P = 0.02, P = 0.01, and P = 0.006). In conclusion, these results suggest that the LAA dysfunction may occur in patients with mitral stenosis in SR and CDTI can successfully be used for the quantification of contraction at the tip of the LAA.

Adult↗

PubMed1995

Atrial and ventricular function after cardioversion of atrial fibrillation.

OBJECTIVE: Previous studies on atrial recovery after cardioversion of atrial fibrillation have not taken into account new knowledge about the pathophysiology of transmitral and transtricuspid flow velocity patterns. It is possible to shed further light on this problem if atrioventricular inflow velocity, venous filling pattern, and atrioventricular annulus motion are recorded and interpreted together. DESIGN: Prospective examinations of mitral and tricuspid transvalvar flow velocities, superior caval and pulmonary venous filling, and mitral and tricuspid annulus motion were recorded using Doppler echocardiography. Examinations were performed before and 24 hours, 1 month, and 20 months after cardioversion. SETTING: Tertiary referral centre for cardiac disease with facilities for invasive and non-invasive investigation. PATIENTS: 16 patients undergoing cardioversion of atrial fibrillation in whom sinus rhythm had persisted for 24 hours or more. RESULTS: Before conversion there was no identifiable A wave in transvalvar flow recordings. The total motion of the tricuspid and mitral annulus was subnormal and there was no identifiable atrial component. Venous flow patterns in general showed a low systolic velocity. After conversion, A waves and atrial components were seen in all patients and increased significantly (P < 0.01) with time. There was a similar time course for the amplitude of annulus atrial components, an increased systolic component of venous inflow, an increased A wave velocity, and a decreased E/A ratio of the transvalvar velocity curves. The ventricular component of annulus motion was unchanged. Changes in general occurred earlier on the right side than the left. CONCLUSIONS: This study indicates that, in addition to the previously known electromechanical dissociation of atrial recovery that exists after cardioversion of atrial fibrillation, there may also be a transient deterioration of ventricular function modulating the transvalvar inflow velocity recordings. Function on the right side generally becomes normal earlier than on the left. Integration of information from transvalvar inflow curves, annulus motion, and venous filling patterns gives additional insight into cardiac function.

Aged↗

PubMed2006

Effect of percutaneous mitral balloon valvuloplasty on left atrial appendage function: a Doppler tissue study.

The aim of this study was to compare left atrial appendage (LAA) functions by Doppler tissue imaging (DTI) before and after percutaneous balloon mitral valvuloplasty (PBMV). Twenty patients with symptomatic rheumatic mitral stenosis who underwent PBMV were included in this study. LAA functions were measured before and after PBMV. To determine LAA functions, LAA late filling (LAALF) velocity, LAA late emptying (LAALE) velocity, and area change of LAA percent were measured. In the DTI records, the first positive wave identical to the LAALE wave after the P wave was accepted as LAA late systolic wave, and the second negative wave identical to the LAALF flow was accepted as late diastolic wave. There was no difference in LAALF velocity and area change of LAA percent after PBMV. LAALE velocity increased after PBMV compared with baseline (P = .005). Late emptying, systolic, and diastolic wave values measured by DTI were found to be increased after PBMV compared with baseline (P = .023, P = .002, and P = .002, respectively). LAALE velocity measured by standard Doppler was increased after PBMV compared with baseline (P = .005), but there was no change in area change of LAA percent or LAALF. Spontaneous echocontrast was present in 7 of the 20 patients before procedure. It completely disappeared (4 patients) or decreased (3 patients) after procedure. In patients with spontaneous echocontrast, LAALE and late emptying, systolic, and diastolic wave values measured by DTI were found to be increased after PBMV compared with baseline. Our results suggest that PBMV improves LAA functions and, thereby, may have a favorable influence on future thromboembolic complications.

Adult↗

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↗

PubMed1999

Atrial and ventricular pressures in atrial flutter.

The hemodynamic effects of atrial flutter (AF) are unknown. The purpose of the present study was to investigate the changes in atrial and ventricular pressures after induction of AF. In 23 patients with paroxysmal AF (age 59 +/- 9 years), a hemodynamic study was performed both during sinus rhythm and after induction of the tachyarrhythmia. During AF, 13 patients showed a fixed 2:1 AV conduction and 10 patients showed variable conduction. Mean right and left atrial pressures increased (P < 0.001) and right and left ventricular end-diastolic pressures decreased (P < 0.001) after induction of AF. Both the increase in mean atrial pressures and the decrease in ventricular end-diastolic pressures were present either in the patients with fixed 2:1 AV (heart rate: 133 +/- 15 beats/min) or in those with variable conduction (heart rate 96 +/- 15 beats/min), but were more marked in the former. AF produces an impairment of atrial function, as evidenced by the increase in mean atrial pressures and reduction in ventricular end-diastolic pressures in the absence of an elevated heart rate. The mechanisms responsible for the increase in mean atrial pressures are unknown; however, atrial contractions against closed AV valves seem to play an important role.

Atrial Flutter↗

PubMed2005

Biplane assessment of left ventricular function during atrial fibrillation at beats with equal subsequent cycles.

BACKGROUND: Prior study has demonstrated that the biplane single-beat method could be used to assess left ventricular function during atrial fibrillation at a beat with equal subsequent cycles. The study was to test whether we could improve the method by measuring a few beats with equal subsequent cycles and cycle-length limits. METHODS: In 75 patients with atrial fibrillation, stroke volume and ejection fraction were determined from simultaneous biplane views of left ventricle for 20 beats using a matrix-array transducer and a biplane Simpson's rule. The influence of cycle lengths on the values of systolic parameters at beats with equal subsequent cycles was examined from the plot of normalized parameters (measured values/average values) against cycle lengths. The values of 1 to 3 beats with equal subsequent cycles and cycle-length limits were averaged and compared with the average values over 20 beats by Bland-Altman and mean percentage difference analysis. The variability of repeat measurements was evaluated in 10 patients. RESULTS: The systolic parameters measured at beats with cycle lengths shorter than 500 ms were usually far below the average values. Agreement and mean percentage difference analysis revealed improved accuracy when 2 or 3 beats with cycle-length limits (>500 ms) were used for assessment. As the variability of averaging 2 or 3 beats is no greater than that of repeat measurements, both methods are equally good. CONCLUSIONS: Accurate assessment of left ventricular systolic function in atrial fibrillation can be obtained by averaging 2 beats with equal subsequent cycles and cycle-length limits (>500 ms).

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PubMed1998

Influence of altered loading conditions on left atrial appendage function in vivo.

This study sought to examine the influence of heart failure treatment on left atrial (LA) appendage function in 10 patients with left ventricular dysfunction. After treatment of heart failure, LA appendage function markedly improved, less dependent on LA and left ventricular functions, which suggests that with altered loading conditions, LA appendage function changes chiefly through its intrinsic contractile property.

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