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PubMed2004

Racial variation in the prevalence of atrial fibrillation among patients with heart failure: the Epidemiology, Practice, Outcomes, and Costs of Heart Failure (EPOCH) study.

OBJECTIVES: This study was designed to determine the association between race and atrial fibrillation (AF) among patients with heart failure (HF). BACKGROUND: Atrial fibrillation is known to complicate HF, but whether its prevalence varies by race, and the reasons why, are not well understood. METHODS: We identified adults hospitalized with confirmed HF within a large integrated healthcare delivery system. We obtained information on demographics, comorbidity, vital signs, medications, and left ventricular systolic function status. "Atrial fibrillation" was defined as AF or atrial flutter documented by electrocardiogram or prior physician-assigned diagnoses. We evaluated the independent relationship between race and AF using multivariable logistic regression. RESULTS: Among 1,373 HF patients (223 African Americans, 1,150 Caucasians), the prevalence of AF was 36.9% (95% confidence interval [CI] 34.3% to 39.5%). Compared with Caucasians, African Americans were younger (mean age 67 vs. 74 years, p < 0.001) and more likely to have hypertension (86.6% vs. 77.7%, p < 0.01) and prior diagnosed HF (79.4% vs. 70.7%, p < 0.01). African Americans had less prior diagnosed coronary disease, revascularization, hypothyroidism, or valve replacement. Atrial fibrillation was much less prevalent in African Americans (19.7%) than Caucasians (38.3%, p < 0.001). After adjustment for risk factors for AF and other potential confounders, African Americans had 49% lower odds of AF (adjusted odds ratio 0.51, 95% CI 0.35 to 0.76). CONCLUSIONS: In a contemporary HF cohort, AF was significantly less common among African Americans than among Caucasians. This variation was not explained by differences in traditional risk factors for AF, HF etiology and severity, and treatment.

Adult↗
PubMed2001

Determinants and clinical significance of natriuretic peptides and hypertrophic cardiomyopathy.

AIMS: Atrial and brain natriuretic peptide levels closely reflect impaired left ventricular function in patients with heart failure. In the present study we assessed the determinants and the clinical significance of atrial and brain natriuretic peptide plasma levels in hypertrophic cardiomyopathy. METHODS AND RESULTS: In 44 patients with hypertrophic cardiomyopathy (40+/-15 years) we evaluated: (a) atrial and brain natriuretic peptide plasma levels; (b) left ventricular hypertrophy; (c) left ventricular ejection fraction; (d) transmitral and pulmonary venous flow velocity patterns, and left atrial fractional shortening; (e) left ventricular outflow tract gradient; (f) maximal oxygen consumption. Left ventricular hypertrophy influenced only brain natriuretic peptide levels (r=0.32;P<0.05). Atrial and brain natriuretic peptide plasma levels did not correlate with left ventricular ejection fraction, but correlated with left ventricular outflow tract gradient (r=0.35;P<0.05; and r=0.40, P=0.022, respectively) and left atrial fractional shortening (r=-0.57;P<0.001, and r=-0.35;P<0.05, respectively). Atrial but not brain natriuretic peptide plasma levels were inversely related to maximal oxygen consumption (r=-0.35;P<0.05). By stepwise multiple regression analysis, left atrial fractional shortening and left ventricular outflow tract gradient were the only predictors of atrial and brain natriuretic peptide plasma levels, respectively. CONCLUSIONS: In hypertrophic cardiomyopathy, atrial natriuretic peptide plasma levels are mainly determined by diastolic function: this explains the relationship with exercise tolerance. In contrast, brain natriuretic peptide plasma levels are mainly determined by left ventricular outflow tract gradient.

Adolescent↗
PubMedDate not supplied

Real-time three-dimensional transthoracic echocardiography.

BACKGROUND: Complex anatomy of intra-cardiac structures requires spatial orientation of image in three dimensions for better understanding and enhanced image interpretation. We evaluated the feasibility and efficacy of the emerging 'real-time three-dimensional transthoracic echocardiography' technique for comprehensive assessment of cardiac anatomy, physiology, pathomorphology and pathophysiology in patients with structural heart disease. METHODS AND RESULTS: Patients with structural heart disease (n=152) were evaluated by conventional two-dimensional transthoracic echocardiography and real-time three-dimensional transthoracic echocardiography using standard protocol. Fifty-six cases were of rheumatic etiology with multi-valvular involvement (mitral stenosis: 32; mitral regurgitation: 29; tricuspid regurgitation: 8; aortic valve disease: 11) and 21 cases of non-rheumatic valvular heart disease. A total of 38 congenital heart disease patients were examined including 23 patients with atrial septal defect. Left ventricular function (n=20) and right ventricular function (n=10) were also assessed using dedicated software. CONCLUSIONS: Results of real-time three-dimensional transthoracic echocardiography mitral valve area assessment by planimetery are comparable to two-dimensional transthoracic echocardiography with additional information about surface anatomy of leaflets and the subvalvular apparatus in real time with clear demarcation of commissural fusion and scallops of leaflets. Enface view of atrial septal defect with direct visualization of shape, size and number of defects, tricuspid valve area by planimetery, right ventricular shape, objective assessment of ventricular volumes and regurgitation vena contracta area are the fields where three-dimensional transthoracic echocardiography was of additive value to conventional two-dimensional transthoracic echcardiography. This study proves clinical feasibility of real-time three-dimensional transthoracic echocardiography but requires further validation of quantitative observations.

Adolescent↗
PubMed1992

Determinants of Doppler indexes of left ventricular diastolic function in normal subjects (the Framingham Heart Study).

Normative Doppler values and determinants of left ventricular (LV) diastolic function in healthy subjects have not been fully elucidated. Subjects from the Framingham Heart Study were examined to describe reference values and determinants of echocardiographic Doppler indexes of diastolic function. One hundred twenty-seven randomly selected, rigorously defined, normal subjects, approximately evenly distributed by sex and age from the third through the eighth decades were studied by Doppler echocardiography. Normative values for 7 frequently used Doppler indexes of LV diastolic function are presented. Doppler indexes of LV diastolic function change dramatically with age; the peak velocity of early filling divided by late filling (peak velocity E/A) ranges from a mean of 2.08 +/- 0.55 for subjects in their third decade to 0.84 +/- 0.29 for those in their eighth decade. A peak velocity E/A ratio less than 1 is abnormal in subjects aged less than 40 years, but occurs in most subjects aged greater than or equal to 70 years. The high correlations between age and Doppler indexes of LV diastolic function are not greatly attenuated after adjustment for other clinical parameters associated with diastolic function; the multivariate partial correlation coefficient between age and peak velocity E/A is -0.80 (p less than 0.0001). Heart rate, PR interval, LV systolic function, sex and systolic blood pressure are minor determinants of Doppler indexes of diastolic function. Body mass index, left atrial diameter, and LV wall thickness, internal dimension and mass have little or no association with Doppler indexes in healthy subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2003

Pulmonary venous flow in pure mitral stenosis and sinus rhythm--does pulmonary hypertension alter pulmonary venous flow velocity?

Pulmonary venous flow (PVF) is influenced by changes in left atrial (LA) pressure and function in various diseases. In mitral stenosis (MS), there is an alteration of LA hemodynamic due to the impaired ventricular filling caused by the stenotic valve and elevation of LA pressure. Although a variety of altered patterns of PVF have been described in MS, the potential influence of pulmonary hypertension, which is frequently associated with MS and has an adverse effect on the functional status and the prognosis of MS, on the PVF pattern is not clearly defined. The aim of this study is to determine the effects of pulmonary hypertension on PVF in patients with MS. Thirty-eight consecutive patients with pure MS and sinus rhythm (30 females, mean age 40 years old) underwent transthoracic and transesophageal echocardiography. Right heart and transseptal catheterization was also performed to measure pulmonary artery systolic pressure (PASP), pulmonary artery diastolic pressure (PADP), pulmonary capillary wedge pressure (PCWP), and left atrial pressure (LAP). The subjects were divided into two groups: group 1 (n = 25)included subjects with PASP < 50 mmHg, group 2(n = 13)included subjects with PASP 50 mmHg. LA size, mitral valve area (MVA), mean mitral gradient (MG), LAP, PASP, PADP, PCWP, and the peak velocity of PV systolic (PVFS), diastolic (PVFD) and atrial reversal flow (PVFAr) were also measured and compared between the two groups. There was no significant difference in age, heart rate, MVA, and LA size between the two groups. LAP, PASP, PADP, PCWP, and MG were significantly higher in group 2. However, PVFS and PVFAr were significantly lower in group2 (46.6 +/- 15.8 vs 29.9 +/- 12.8 cm/sec, P < 0.005; 22.1 +/- 6.8 vs 17.3 +/- 5.9 cm/sec, P < 0.05). There was no significant difference of PVFD between the two groups. PVFS had negative correlation to LAP, MG, PASP, PADP, and PCWP. PVFAr had negative correlation with PASP, PADP, and PCWP. There was no significant correlation between PVFAr and MVA. LA size and LAP. In conclusion, in patients with pure MS and sinus rhythm, PVF, especially PVFAr, is influenced by the presence of pulmonary hypertension.

Adult↗
PubMed1997

The effect of iron overload in the hearts of patients with beta-thalassemia.

BACKGROUND AND HYPOTHESIS: An important complication of beta-thalassemia is iron deposition in cardiac tissues resulting in fibrosis and dysfunction. Our aim was the investigation of the possible clinical effect of iron loading in the heart of patients with beta-thalassemia prior to the appearance of symptoms of depressed systolic function. METHODS: Thirty-five patients with beta-thalassemia, of whom 24 had the major type (Group 1) and 11 had the intermedia type (Group 2) were studied. Eleven age- and gender-matched controls were also studied (Group 3). All patients were evaluated echocardiographically and were shown to have normal left ventricular systolic function and dimensions. Serum ferritin, atrial natriuretic peptide (ANP), left atrial diameter (LAD), peak early mitral inflow velocity (E), peak late mitral inflow velocity (A), E/A ratio, deceleration time of the mitral inflow E wave (DT), and isovolumic relaxation time (IVRT) were measured. RESULTS: Univariate analysis showed that both groups of patients had similarly increased LAD and ANP plasma levels. Group 1 had a higher E/A ratio (2.27 +/- 0.88) SS than Group 2 (1.69 +/- 0.47, p = 0.05) and Group 3 (1.50 +/- 0.38, p = 0.01). Serum ferritin was significantly higher in Group 1 (3.526 +/- 0.352) than in Group 2 (2.808 +/- 0.288, p < 10(-5) and Group 3 (2.139 +/- 0.124, p < 10(-5). Multivariate analysis showed that ANP is a factor that is affected by the LAD and E/A ratio and that serum ferritin levels affect the LAD and E/A ratio. CONCLUSIONS: Although LAD and ANP levels are increased in patients with beta-thalassemia, the increased serum ferritin levels of patients seem to affect left atrial size and E/A ratio. ANP secretion is consecutively affected by these factors.

Adult↗
PubMed2006

Current surgical therapy for Ebstein anomaly in neonates.

OBJECTIVE: Neonates with profound heart failure resulting from Ebstein anomaly have historically had poor outcomes. We report our institutional experience with the surgical management of Ebstein anomaly in severely symptomatic neonates. METHODS: A retrospective review of all patients (n = 16) undergoing neonatal intervention for Ebstein anomaly between 1992 and 2005 has been carried out. The indications for operation were overt heart failure, cyanosis, and acidosis associated with tricuspid regurgitation, depressed right ventricular function, and severe cardiomegaly. The magnitude of cardiac enlargement was assessed by cardiothoracic ratio and Great Ormond Street ratio (area of right atrium + atrialized right ventricle/area of functional left atrium + left ventricle). The operative strategy was first to assess for the possibility of tricuspid valve repair with or without right ventricular outflow tract reconstruction. If this was not feasible, then right ventricular exclusion was performed by oversewing the tricuspid valve with a pericardial patch. A reduction atrioplasty was done and, depending on the extent of the atrialized portion of the right ventricle, plication was performed. A modified Blalock-Taussig shunt provided pulmonary blood flow. This univentricular approach (Starnes procedure) evolved to include a fenestration in the tricuspid valve patch to allow for right ventricular decompression. Analysis included overall and group-specific survival as well as the testing of perioperative clinical, morphologic, and surgical variables for correlation with mortality and morbidity. RESULTS: Mean age and weight at operation were 8 +/-10 days and 3.1 +/- 0.4 kg. Tricuspid valve repair was undertaken in 3 patients with 1 requiring conversion to right ventricular exclusion 3 months after the initial operation. In those with right ventricular exclusion, the tricuspid valve patch was fenestrated in 10 and nonfenestrated in 3. One patient had heart transplant as the initial procedure. There were 5 hospital deaths (31%) and no late deaths among the survivors. Survival in the cohort with a fenestrated tricuspid valve patch was 80% (8/10) versus 33% (1/3) for the nonfenestrated group. This difference did not reach statistical significance, although the trend seems clinically important. There was no difference in the cardiothoracic ratio (0.82 fenestrated vs 0.84 nonfenestrated: P = .802) or the Great Ormond Street ratio (1.2 fenestrated vs 1.02 nonfenestrated: P = .477) between the two groups. Among the 9 survivors of right ventricular exclusion, 3 have had completion of their Fontan, and all 9 have undergone a bidirectional Glenn procedure. All operations including homograft placement in the right ventricular outflow tract, whether during repair or during right ventricular exclusion, ended in death. CONCLUSION: Right ventricular exclusion with a fenestrated tricuspid valve patch combined with right atrioplasty and right ventriculoplasty and a Blalock-Taussig shunt (Starnes procedure) has provided effective palliation for neonates presenting with critical Ebstein anomaly and a tricuspid valve that cannot be repaired.

Cardiac Surgical Procedures↗
PubMed1992

[Doppler echocardiography in the evaluation of left ventricular diastolic function in hypertension].

Twenty-five hypertensive patients were examined using Doppler echocardiography to determine the diastolic function of the left ventricle. Twenty-two parameters were analysed and the diastolic indexes were compared with the results of a control group of ten healthy volunteers. Patients with hypertension showed significant left ventricular hypertrophy with increased left ventricular mass and dilated left atrium. Eighty-five percent of the hypertensive patients were found to have impaired diastolic function. The peak velocity of the early, and late diastolic phase and also the duration of acceleration and deceleration are considered to be necessary in the investigation of the diastolic function of left ventricle. All the other parameters can be determined using the above mentioned ones. The late diastolic transmitral flow, the atrial filling velocity, the time of deceleration and acceleration and also the time velocity integral increased significantly. However, the early diastolic filling fraction decreased significantly. The abnormalities in left ventricular diastolic function and also the atrial enlargement may be the early signs of hypertensive heart disease and therefore have a great importance in the therapy.

Diastole↗
PubMed1990

An experimental technique for heart-lung transplantation in subprimate models.

The success of heart-lung transplant experiments in subprimate models has been limited because most techniques include total pulmonary denervation, which causes respiratory problems, blood loss, and subsequent death. Using 20 subprimates (12 domestic swine and 8 mongrel dogs), we tested a heterotopic heart-single lung transplant method intended to preserve unilateral pulmonary innervation and to reduce blood loss. After native right pneumonectomy, the donor heart and right lung were transplanted en bloc. Anastomotic sites included the right primary bronchus, the superior vena cava, and the aorta. Selective left bronchial intubation and partial occlusion techniques eliminated the need for cardiopulmonary bypass and mediastinal dissection. All 10 recipient animals survived the operation, and the need for blood transfusions was minimal (1.1 +/- 0.7 [mean +/- SD] units/procedure). Donor and native lung function, assessed by selective left atrial blood gases, were similar: mean PO(2) was 229 +/- 31 mmHg and 180 +/- 25 mmHg, respectively; and mean PCO(2), 36 +/- 13 mmHg and 38+/-2 mmHg, respectively. Nine recipients were weaned from mechanical ventilation with a mean PCO(2) of 38+/-4 mmHg. Preserving unilateral pulmonary innervation allows normal respiration, and minimizing blood loss increases operative survival. Our method of heterotopic heart-single lung transplantation is reliable and could provide a functional heart-lung allograft for conducting future experimental studies of heart-lung transplantation.

Journal Article↗
PubMed1991

The spectrum of left ventricular filling in severe aortic stenosis.

To assess left ventricular diastolic filling in valvular aortic stenosis, pulsed Doppler echocardiography was used prospectively in 35 patients with severe aortic stenosis (valve area less than 1 cm2) and in 38 age-matched normal subjects. Twenty-seven patients had a normal left ventricular systolic function at rest (ejection fraction greater than 0.50) and a normal or only slightly increased mean pulmonary capillary wedge pressure (mean 11 +/- 4 mm Hg). Eight patients had a poor left ventricular systolic function (ejection fraction: 0.28 +/- 0.10) and an elevated mean pulmonary capillary wedge pressure (mean: 36 +/- 9 mm Hg). The Doppler derived filling parameters were correlated with hemodynamic data, left ventricular wall thickness derived from M-mode echocardiograms, heart rate and atrio-ventricular (A-V) conduction delay using stepwise multiple correlation. The data of this study suggest that left ventricular filling is significantly impaired in patients with severe aortic stenosis and left ventricular hypertrophy with an increase in late diastolic (A-wave) velocity, an increase in the A/E ratio, a decrease in the first one-half filling fraction and a prolongation of early diastolic deceleration time. These changes in filling hemodynamics are associated with alterations in mean pulmonary capillary wedge pressure, left ventricular wall thickness, heart rate and A-V conduction delay. When heart failure develops as a result of impaired left ventricular systolic function, an increase in left atrial filling pressure is associated with a shift of left ventricular filling towards early diastole with a 'normalisation' of the transmitral flow velocity curve. In extreme cases, a progression towards a 'restrictive' filling pattern is found with a marked shortening of the left ventricular early diastolic deceleration time. In the presence of high filling pressures, increased left atrial driving pressure (derived from the mean pulmonary capillary wedge pressure) is associated with changes in the left ventricular filling pattern irrespective of the presence and the degree of myocardial hypertrophy.

Adolescent↗
PubMed1995

Fatty acid oxidation and cardiac function in the sodium pivalate model of secondary carnitine deficiency.

Carnitine-deficiency syndromes are often associated with alterations in lipid metabolism and cardiac function. The present study was designed to determine whether this is also seen in an experimental model of carnitine deficiency. Carnitine deficiency was induced in male Sprague-Dawley rats supplemented with sodium pivalate for 26 to 28 weeks. This treatment resulted in nearly a 60% depletion of myocardial total carnitine content as compared with control hearts. When isolated working hearts from these animals were perfused with 5.5 mmol/L glucose and 1.2 mmol/L palmitate and subjected to incremental increases in left-atrial filling pressures, cardiac function remained dramatically depressed. The effects of carnitine deficiency on glucose and palmitate utilization were also assessed in hearts perfused at increased workload conditions. At this workload, function was depressed in carnitine-deficient hearts, as were rates of 1.2-mmol/L [U-14C]-palmitate oxidation, when compared with control hearts (544 +/- 37 vs 882 +/- 87 nmol/g dry weight.min, P < .05). However, glucose oxidation rates from 5.5 mmol/L [U-14C]-glucose were slightly increased in carnitine-deficient hearts. To determine whether the depressed fatty acid oxidation rates were a result of reduced mechanical function in carnitine-deficient hearts, the workload of hearts was reduced. Under these conditions, mechanical function was similar among control and carnitine-deficient hearts. Palmitate oxidation rates were also similar in these hearts (526 +/- 69 v 404 +/- 47 nmol/g dry weight.min for control and carnitine-deficient hearts, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗
PubMed2003

Congenital pulmonary-systemic collateral vein without obstructed left atrial egress is associated with conotruncal anomalies.

We present a case of congenital pulmonary systemic collateral vein associated with truncus arteriosus. Pulmonary systemic collateral vein with nonobstructed left atrial egress is different from those with obstructed left atrial egress in that it is functionally redundant. Including this case, 8 patients among 33 reported cases with pulmonary systemic collateral veins have had nonobstructed left atrial egress. Association with conotruncal anomalies in 4 of these 8 patients, as well as the reported finding that neural crest cells are distributed not only in the conotruncus but also in the cardinal vein, indicates that neural crest cells play roles in remodeling of the systemic venous system.

Collateral Circulation↗
PubMed2005

Predictors of left atrial spontaneous echocardiographic contrast or thrombus formation in stroke patients with sinus rhythm and reduced left ventricular function.

The objective of the present study was to identify predictors of left atrial spontaneous echocardiographic contrast (SEC) or thrombus in patients with stroke with sinus rhythm and left ventricular dysfunction. Of 500 consecutive patients with stroke, 48 with sinus rhythm and reduced left ventricular ejection fractions (EFs) < or =45% were examined. Ten patients presented with SEC or thrombus. The patients with SEC or thrombus had larger left atrial diameters (47 +/- 4 vs 42 +/- 6 mm, p <0.05), smaller EFs (30 +/- 9% vs 38 +/- 8%, p <0.01), and slower left atrial appendage (LAA) flow velocities (42 +/- 13 vs 61 +/- 17 cm/s, p <0.01). Multivariate analysis identified EF < or =35% and LAA flow velocity < or =55 cm/s as predictors of SEC or thrombus (p <0.05). Patients with stroke with sinus rhythm and moderate- to high-grade reduction of the left ventricular EF represent a risk group for a left atrial source of embolism and should undergo transesophageal echocardiography.

Adolescent↗
PubMed1983

Beat-to-beat left ventricular performance in atrial fibrillation: radionuclide assessment with the computerized nuclear probe.

There is wide beat-to-beat variability in cycle length and left ventricular performance in patients with atrial fibrillation. In this study, left ventricular ejection fraction and relative left ventricular volumes were evaluated on a beat-to-beat basis with the computerized nuclear probe, an instrument with sufficiently high sensitivity to allow continuous evaluation of the radionuclide time-activity curve. Of 18 patients with atrial fibrillation, 5 had mitral stenosis, 6 had mitral regurgitation, and 7 had coronary artery disease. Fifty consecutive beats were analyzed in each patient. The mean left ventricular ejection fraction ranged from 17 to 51%. There was substantial beat-to-beat variation in cycle length and left ventricular ejection fraction in all patients, including those with marked left ventricular dysfunction. In 14 patients who also underwent multiple gated cardiac blood pool imaging, there was an excellent correlation between mean ejection fraction derived from the nuclear probe and gated ejection fraction obtained by gamma camera imaging (r = 0.90). Based on beat-to-beat analysis, left ventricular function was dependent on relative end-diastolic volume and multiple preceding cycle lengths, but not preceding end-systolic volumes. This study demonstrates that a single value for left ventricular ejection fraction does not adequately characterize left ventricular function in patients with atrial fibrillation. Furthermore, both the mean beat-to-beat and the gated ejection fraction may underestimate left ventricular performance at rest in such patients.

Aged↗
PubMed2001

Clinical significance of noninvasive assessment of left ventricular diastolic function by Doppler echocardiography.

Transmitral flow velocity pattern obtained by the pulsed Doppler technique reflects left ventricular (LV) diastolic function, but an increase in left atrial pressure pseudonormalizes the flow pattern and masks diastolic dysfunction. We propose an index to assess LV diastolic function using color M-mode Doppler echocardiography and the base-line shift technique. This index, flow propagation velocity, represents the average velocity of early diastolic LV filling flow from the mitral orifice to mid-ventricle. In patients with ischemic heart disease and dilated cardiomyopathy including those with pseudonormalized transmitral flow pattern, flow propagation velocity had a good correlation with the time constant of early diastolic LV pressure decay (Tau), indicating that flow propagation velocity is a useful noninvasive parameter of diastolic function which does not pseudonormalize. We also found a significant correlation between flow propagation velocity and Tau in hypertrophic cardiomyopathy patients in contrast to inadequate or no correlation between each of the conventional parameters and Tau. In addition, our recent data suggest that flow propagation velocity was distinctly decreased even in the patients with hypertension who did not show significant increase in LV mass index. Flow propagation velocity is a unique noninvasive parameter of LV diastolic function, which can sensitively and accurately detect the diastolic impairment in patients with different types of cardiac diseases with various loading conditions.

Blood Flow Velocity↗
PubMed1989

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

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

Animals↗
PubMed2001

Transthoracic and transesophageal echocardiographic indices predictive of sinus rhythm maintenance after cardioversion of atrial fibrillation: an echocardiographic study during direct current shock.

BACKGROUND: Up to 57% of atrial fibrillation (AF) recurrences after cardioversion take place during the first 30 days following direct current shock (DCS) delivery. Previous echocardiographic studies on sinus rhythm (SR) maintenance after cardioversion have focused mainly on parameters recorded before DCS, while other studies have reported on the indices recorded soon after delivery of the shock. METHODS: Therefore, we investigated 18 patients with nonrheumatic AF, selected to undergo DCS, by both transthoracic (TTE) and transesophageal (TEE) echocardiography performed within 10 minutes before and after the electrical shock delivery. TTE was utilized for the evaluation of left atrium and left ventricle shape as well as for mitral Doppler flow sampling, while TEE was used to evaluate left atrial appendage (LAA) morphology and function, to score the LAA spontaneous echo contrast, and to evaluate the flow of left superior pulmonary vein; the transesophageal probe was left in situ during the electrical procedure. Thirty days after cardioversion, 10 (55%) patients maintained SR (Group 1) while 8 (45%) reverted to AF (Group 2). We compared the mean values of the parameters recorded in the two groups both before and after DCS. RESULTS: Although many parameters of pre- and postcardioversion analysis proved to be significantly different between the two groups, the most marked differences were exhibited by the following postcardioversion indices: Peak Doppler flow velocity of the end-diastolic mitral flow (30.10 +/- 5.24 vs. 20.50 +/- 6.32 cm/sec, P = 0.003); sum of peak velocities of the end-diastolic contraction (A) and relaxation (A(1)) of LAA (A + A(1) = 58.20 +/- 17.02 vs. 31.25 +/- 9.27 cm/sec, P = 0.001); duration of A + A(1) (162.70 +/- 27.01 vs. 133.75 +/- 5.31 msec, P = 0.002); and sum of durations of the early diastolic forward (E) and reverse (E(1)) flow of LAA (101.90 +/- 35.15 vs. 53.33 +/- 16.33 msec, P = 0.006). CONCLUSIONS: Using a single echocardiographic examination during DCS and after induction of anesthesia, without further discomfort to patients, we were able to identify useful parameters for the prediction of future electrical activity of the heart before as well as soon after DCS. Postcardioversion indices, derived by both TTE and TEE, were even more predictive of SR maintenance after 1 month than precardioversion parameters.

Adult↗
PubMed1995

Nonrheumatic atrial fibrillation: a brief overview.

OBJECTIVE: To review the effectiveness of current approaches in the treatment of patients with nonrheumatic atrial fibrillation (NRAF). DESIGN: Review of the available English-language articles on the epidemiology, clinical consequences, management and prevention of stroke in patients with NRAF. RESULTS: The incidence of atrial fibrillation increases steadily in both sexes in relation to age. The clinical independent risk factors for NRAF are diabetes mellitus, hypertension, recent heart failure, valvular heart disease and myocardial infarction. The echocardiographic predictors are left atrial enlargement, reduced left ventricular function and left ventricular wall thickness. The clinical consequences of NRAF are increased risk of stroke, mortality and left ventricular dysfunction. The management of NRAF includes correction of cause, termination of acute episode, maintenance of sinus rhythm, ventricular rate control and prevention of systemic embolism. CONCLUSION: NRAF is a common cardiac arrhythmia that is associated with high incidence of mortality and systemic embolism. Anticoagulation is effective in preventing embolism with acceptable risk of major bleeding. Acetylsalicylic acid is less effective but a reasonable alternative when anticoagulation is contraindicated.

Adult↗