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PubMed2002

Atrial size and transport function after the Maze III procedure for paroxysmal atrial fibrillation.

BACKGROUND: The Maze procedure is a curative surgical therapy for atrial fibrillation, restoring sinus rhythm and improving quality of life. Because the procedure results in tissue scarring, the atrial transport function is most likely affected. METHODS: Seventeen patients with paroxysmal atrial fibrillation underwent the Maze III procedure without any concomitant valve operation. Atrial size and transport function were measured before and at 2, 6, and 24 months after operations with two-dimensional echocardiography and pulsed-wave Doppler. RESULTS: Fifteen patients (88%) had signs of left atrial contractions as shown by the presence of a transmitral atrial filling wave on Doppler echocardiography at 6 months follow-up. The transmitral early filling wave and atrial filling wave were measured to calculate the early filling/atrial filling wave ratio, which increased from 1.2 before to 1.9 at 2 months after the Maze procedure (nonsignificant), and further to 2.8 at 24 months (p = 0.02). A decrease in the right and left atrial size was seen at 2 months after an operation, but no further decrease occurred. CONCLUSIONS: In patients with paroxysmal atrial fibrillation, there is a progressive increase in the transmitral early filling/atrial filling wave ratio after the Maze procedure, consistent with a gradual decrease in the left atrial transport function.

Adult↗
PubMed2003

Left atrial size after cardioversion for atrial fibrillation: effect of external direct current shock.

OBJECTIVE: The aim of this study was to evaluate the effect of external direct current (DC) shock on left atrial (LA) dimension and volumes after cardioversion for atrial fibrillation, and the relation between LA size and atrial function. METHODS: We evaluated 180 patients who were randomly cardioverted with DC shock (90 patients) or drugs (90 patients). Echocardiographic evaluations included LA size and volumes. LA passive and active emptying volumes were calculated, and LA function was measured as atrial ejection force. Changes in LA diameters and volumes were correlate with atrial systolic function. RESULTS: The LA was dilated in all patients during arrhythmia and decreased after the restoration of sinus rhythm. The entity of reduction was different in the 2 groups of patients. LA maximal and minimal volumes were increased after DC shock as compared with patients treated with drugs (LA maximal volume 34 +/- 4 vs 31 +/- 5; P <.01; LA minimal volume 18 +/- 2.6 vs 15 +/- 3.6; P <.01). The atrial function was also depressed after DC shock and the delay in the recovery of atrial contractility was related to LA dilation. Patients treated with drugs had a higher atrial ejection force that was associated with a more marked reduction in LA maximal volume after the restoration of in sinus rhythm. A relationship between LA volumes and atrial ejection force was observed in the group of patients with depressed atrial mechanic function (r = -0.78; P <.001). The active emptying fraction was lower, although not significantly, in this group, whereas the conduit volume was increased. CONCLUSION: External DC shock induced a depressed atrial mechanic function in many patients and this was associated with a persistence of LA dilation.

Adult↗
PubMed2005

Doppler echocardiographic prediction of recurrent atrial fibrillation following cardioversion.

BACKGROUND: Cardioversion for atrial fibrillation (AF) is associated with impairment of left atrial mechanical function and increased risk of thrombus formation with subsequent embolisation. Measuring atrial mechanical function is of interest to determine the individual risk of thromboembolism and the risk of recurrent AF. METHODS: We included 112 consecutive patients with AF and planned cardioversion. Serial echocardiographic measurements of left atrial size and Doppler measurement of mitral valve peak A wave velocities were obtained at days 0, 1, 2, 3, and 28 following cardioversion. These measurements and clinical parameters were related to clinical events and recurrent AF within 4 weeks following cardioversion. Cardioversion was achieved in 100 patients. RESULTS: AF-recurrence within 4 weeks was 23.9% and 45.8% for patients with < or = and > 6 weeks AF-duration, respectively (p=0.04). Peak A wave velocities were significantly lower up to 2 days following cardioversion in patients with AF-recurrence. A peak A wave velocity < 52 cm/s at day 1 resulted in an odds ratio of 5.0 (95% CI: 1.4-18.6) for recurrence of AF. In multiple logistic regression analysis, peak A wave velocity at day 1 remained the only independent predictor of recurrent AF. Left atrial diameter did not correlate with recurrence of AF. CONCLUSIONS: A single measurement of mitral peak A wave velocity 1 day following cardioversion is predictive of AF recurrence. This method is feasible for risk estimation with potential therapeutic implications.

Atrial Fibrillation↗
PubMedDate not supplied

The normal pattern of pulmonary venous flow on pulsed Doppler examination of the human fetus.

The pattern of pulmonary venous flow was studied in 52 normal fetuses between 16 weeks gestation and term. A characteristic flow profile was defined. This was similar to that described in the child and adult and different from the pattern of flow in the systemic veins described in the fetus. The velocity of flow increased with gestation and was not influenced by heart rate. The velocity-time integral showed that systolic flow was 2.0 +/- 0.3 times the flow in diastole. Pulsed Doppler echocardiography demonstrates a distinctive pattern of pulmonary venous blood flow that reflects left atrial hemodynamics.

Adult↗
PubMed1989

Factors determining maintenance of sinus rhythm after chronic atrial fibrillation with left atrial dilatation.

Successful therapy of atrial fibrillation (AF) has been reportedly influenced by a variety of factors including patient age, type of underlying heart disease, duration of arrhythmia, left ventricular function and left atrial (LA) size. To determine which of these factors are associated with maintenance of sinus rhythm after conversion, 43 patients with symptomatic chronic AF in the setting of a dilated left atrium (greater than or equal to 45 mm, range 45 to 78) were followed for at least 6 months after the return of sinus rhythm. Class IA drugs, IC drugs or amiodarone were used for therapy. Life table analysis showed sinus rhythm to be maintained in 81% for 6 months, 79% for 12 months and 60% for 24 months. Factors positively associated with success were conversion with drug therapy alone, duration of chronic AF less than or equal to 1 year, absence of mitral valve disease and LA dimension less than or equal to 60 mm (all p less than 0.05). Patient age, left ventricular function and presence of coronary disease were not associated with outcome. Thus, patients with moderate LA dilatation (45 to 60 mm) and a short duration of chronic AF can often be maintained in sinus rhythm, especially if they convert with pharmacologic intervention alone.

Aged↗
PubMed1991

Hemodynamic response to intracoronary infusion of atrial natriuretic factor in patients with normal or altered left ventricular function.

To assess the effects of atrial natriuretic factor (ANF) on cardiac function, synthetic human ANF was infused directly into the left main coronary artery of eight patients with congestive heart failure (CHF) and six subjects with normal left ventricular (LV) function (controls) who underwent cardiac catheterization. ANF infusion at the incremental rates of 60, 125, 400, and 800 ng/min induced a dose-related increase in plasma ANF concentrations in the coronary sinus, from 1,223 +/- 590 to 3,923 +/- 1,123 pg/ml in patients with CHF (p less than 0.01) and from 1,041 +/- 605 to 2,710 +/- 1,741 pg/ml in controls (p less than 0.01). Peripheral plasma ANF concentrations (femoral artery) increased from 538 +/- 278 to 752 +/- 262 pg/ml (p less than 0.01) in patients with CHF and from 193 +/- 63 to 401 +/- 147 pg/ml (p less than 0.01) in controls. The increase in peripheral or coronary sinus plasma ANF concentrations did not differ between patients with CHF and controls. At the three lowest ANF infusion rates, cardiac index (CI), systemic vascular resistance (SVR), and LV contractility assessed by peak positive dP/dt remained unchanged both in patients with CHF and in controls. At the highest ANF infusion rate, CI increased from 2.18 +/- 0.53 to 2.54 +/- 0.49 L/min/m2 (p less than 0.01) and SVR decreased from 14.6 +/- 3.6 to 12.8 +/- 4.5 mm Hg.min/L (p less than 0.01) in patients with CHF. There was no associated change in heart rate (HR), mean arterial blood pressure (MAP), cardiac filling pressures, or peak positive dP/dt.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Interpretation of cardiac pathophysiology from pressure waveform analysis: the left-sided V wave.

The left-sided V wave is dependent on both left atrial and ventricular pressure/volume filling relationship. The cardiac rhythm and timing of atrial systole also influences the V wave. The morphology of the V wave can reflect the severity of mitral regurgitation with stenosis, but valve areas in this setting may be better assessed by a pressure half-time method. Finally, as queried in our first patient example, V wave alternans is a reflection of left ventricular pressure alternans in a failing heart. Other signs of poor left ventricular function in Figure 1 also included an elevated minimal diastolic pressure and markedly elevated left ventricular end diastolic pressure. Hemodynamic findings of poor left ventricular function will be addressed in detail in a later "Rounds."

Aged↗
PubMedDate not supplied

Hemodynamic response to exercise-induced myocardial ischemia detected by transmitral filling patterns derived from Doppler echocardiography.

There is still controversy as to the manner in which Doppler-derived transmitral filling patterns change because of myocardial ischemia. To evaluate the effects of exercise-induced ischemia on Doppler-derived filling patterns, 28 patients were examined at rest and during three stages of supine bicycle exercise (0.5, 1.0, and 1.5 W/kg). The peak early (E) and integrated early (Ei) and peak late (A) and integrated late (Ai) diastolic flow velocities, as well as their ratios (E/A, Ei/Ai), were compared between patients with exercise-induced ischemia but no wall-motion abnormalities at rest (ischemia group, n = 13) and those with akinetic scars from previous infarction but no exercise ischemia (scar group, n = 15). Normal subjects with no evidence of heart disease served as a control group (n = 11). At maximal workload the ischemia group showed a significantly lower peak flow velocity at atrial contraction than the control and scar group (0.74 +/- 0.18 vs 1.08 +/- 0.25 and 0.89 +/- 0.19 m/sec, respectively; p < 0.05) and also a significantly lower flow velocity integral at atrial contraction (8.24 +/- 2.2 vs 12.81 +/- 4.8 and 11.32 +/- 3.6 cm, respectively; p < 0.05). Therefore, the atrial contribution to filling was diminished during ischemia (36.2% +/- 9.2% vs 47.3% +/- 6.4% and 48.4% +/- 13.8%, respectively; p < 0.05). By maintaining the early filling rate during ischemia, the reduced atrial contribution resulted in a significantly higher E/A ratio (1.48 +/- 0.31 vs 1.05 +/- 0.15 and 1.16 +/- 0.44, respectively) and Ei/Ai ratio (2.0 +/- 1.06 vs 1.09 +/- 0.26 and 1.24 +/- 0.79, respectively). The assessment of Doppler-derived transmitral filling during exercise-induced ischemia shows mainly early diastolic filling, which is in contrast to the profile of impaired relaxation usually associated with ischemia. Evidence of exercise-induced ischemia leading to greater increases in left atrial pressure suggests that transmitral filling patterns are more closely related to hemodynamic status than to diastolic function.

Aged↗
PubMed1995

[Left ventricular hypertrophy and left atrial morphology in untreated hypertensive patients].

The level of arterial pressure is not the sole determinant of cardiac and vascular adaptation to hypertension. In order to identify other factors (such as preload) we categorized by echocardiography, 55 never treated hypertensive patients and 39 age and gender-matched normal subjects, according to values of relative wall thickness and left ventricular mass index. Normal left ventricular anatomy was found in 63% hypertensives, whereas among hypertensives 7% had "concentric left ventricular remodeling", 16% concentric left ventricular hypertrophy and 14% had eccentric left ventricular hypertrophy. Systolic left atrial area (LA) was obtained from the four-chamber views. Mitral peak early diastolic (E) and late diastolic (A) flow velocity was assessed by Doppler. Because clinical characteristics such age and sex differed among the 5 groups only results of ANCOVA were reported (means +/- SD). [table: see text] We conclude that eccentric left ventricular hypertrophy may be associated with a parallel increase of left atrial area. Thus the association of an increase of cardiac volume in hypertensive patients with normal diastolic function suggest that volume overload may modulate the effect of arterial pressure on cardiac morphology.

Adult↗
PubMed2002

Visualization of left atrial appendage and assessment of its function by transthoracic second harmonic imaging and contrast-enhanced pulsed Doppler.

BACKGROUND: Low flow velocity within the left atrial appendage, as assessed by transoesophageal echocardiography, is a predictor of thromboembolism and of a low success rate of cardioversion of atrial fibrillation. However, the semi-invasive nature does limit its serial application as a screening technique. METHODS AND RESULTS: We investigated the value of transthoracic second harmonic echocardiography and pulsed Doppler at baseline and after intravenous contrast injection to visualize the left atrial appendage and assess blood flow velocities within its cavity. We studied 51 consecutive patients undergoing transoesophageal echocardiography. After transoesophageal echocardiography, transthoracic second harmonic imaging was performed and the left atrial appendage was visualized in 46 patients. Interpretable pulsed Doppler tracings of left atrial appendage flow were obtained at baseline in 39 patients and in 45 patients during Levovist administration. The correlations between peak emptying velocity of left atrial appendage as measured by transoesophageal echocardiography and by transthoracic standard and contrast-enhanced Doppler were 0.81 and 0.91, respectively. The agreement between transoesophageal echocardiography and transthoracic contrast-enhanced pulsed Doppler echocardiography in classifying left atrial appendage flow velocity patterns was 93%. Left atrial appendage thrombus was detected by transthoracic second harmonic imaging in only one of the eight patients shown by transoesophageal echocardiography to have a thrombus. However, all but one of the patients with left atrial appendage thrombus and/or spontaneous echocardiographic contrast at transoesophageal echocardiography had <30cm/s left atrial appendage flow velocity by transthoracic Doppler. CONCLUSIONS: This study shows that left atrial appendage can be visualized by transthoracic second harmonic imaging and that the flow velocity within its cavity is reliably measured by pulsed Doppler in a substantial fraction of patients. Contrast enhancement improves the feasibility and the accuracy of transthoracic evaluation of left atrial appendage flow velocity. The practical value of these results in predicting thromboembolic risk and success of cardioversion of atrial fibrillation needs to be proved by prospective studies.

Aged↗
PubMed2006

Cardiovascular features of heart failure with preserved ejection fraction versus nonfailing hypertensive left ventricular hypertrophy in the urban Baltimore community: the role of atrial remodeling/dysfunction.

OBJECTIVES: The purpose of this study was to identify cardiovascular features of patients with heart failure with preserved ejection fraction (HFpEF) that differ from those in individuals with hypertensive left ventricular hypertrophy (HLVH) of similar age, gender, and racial background but without failure. BACKGROUND: Heart failure with preserved ejection fraction often develops in HLVH patients and involves multiple abnormalities. Clarification of changes most specific to HFpEF may help elucidate underlying pathophysiology. METHODS: A cross-sectional study comparing HFpEF patients (n = 37), HLVH subjects without HF (n = 40), and normotensive control subjects without LVH (n = 56). All subjects had an EF of >50%, sinus rhythm, and insignificant valvular or active ischemic disease, and groups were matched for age, gender, and ethnicity. Comprehensive echo-Doppler and pressure analysis was performed. RESULTS: The HFpEF patients were predominantly African-American women with hypertension, LVH, and obesity. They had vascular and systolic-ventricular stiffening and abnormal diastolic function compared with the control subjects. However, most of these parameters either individually or combined were similarly abnormal in the HLVH group and poorly distinguished between these groups. The HFpEF group had quantitatively greater concentric LVH and estimated mean pulmonary artery wedge pressure (20 mm Hg vs. 16 mm Hg) and shorter isovolumic relaxation time than the HLVH group. They also had left atrial dilation/dysfunction unlike in HLVH and greater total epicardial volume. The product of LV mass index and maximal left atrial (LA) volume best identified HFpEF patients (84% sensitivity, 82% specificity). CONCLUSIONS: In an urban, principally African American, cohort, HFpEF patients share many abnormalities of systolic, diastolic, and vascular function with nonfailing HLVH subjects but display accentuated LVH and LA dilation/failure. These latter factors may help clarify pathophysiology and define an important HFpEF population for clinical trials.

Age Distribution↗
PubMed1993

Load independence of early diastolic filling parameters in the anesthetized canine model.

To evaluate radionuclide diastolic filling indices during acute pharmacologic changes in ventricular loading, 11 atrially paced dogs underwent simultaneous micromanometer left atrial and left ventricular pressure measurements. During phenylephrine infusion, systolic blood pressure increased from 110 +/- 16 (s.d.) to 147 +/- 19 mmHg (p < 0.01), causing the atrioventricular gradient to increase from 5 +/- 2 to 8 +/- 5 mmHg (p < 0.03) with no change in the time constant of isovolumic relaxation (Tau). Absolute peak filling rate increased from 40 +/- 21 to 59 +/- 44 kcts/sec (p < 0.05), but there was no change in first-half filling fraction. During dobutamine infusion, Tau shortened from 43 +/- 13 msec to 33 +/- 5 msec (p < 0.01) and first-half filling fraction increased from 39% +/- 19% to 56% +/- 18% (p < 0.05), with no change in atrioventricular gradient or absolute peak filling rate. Absolute changes from baseline for the first-half filling fraction were inversely proportional to absolute changes in Tau (r = -0.76, p < 0.05). We conclude that the left ventricular absolute peak filling rate is a load dependent index of diastolic function. In contrast, the radionuclide first-half filling fraction is independent of loading conditions, but is sensitive to substantial alterations in the rate of left ventricular isovolumic myocardial relaxation.

Animals↗