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PubMed1983

The right auricle of the heart is an endocrine organ. Cardiodilatin as a peptide hormone candidate.

A new polypeptide hormone candidate regulating vascular smooth muscle function was extracted from porcine atrial tissue. The purification steps were followed by a bioassay. The hormonally active substance has been analyzed and found to be a small polypeptide exhibiting a molecular weight of about 7500 and is named "cardiodilatin" (CDD). Further chemical data on this new hormone will be published elsewhere. A partial amino acid sequence of cardiodilatin is offered and shows that among the well known hormones or neuropeptides, none exhibit a homologue partial sequence.

Amino Acid Sequence↗
PubMedDate not supplied

Relationship between left ventricular wall thickness and left atrial size: comparison with other measures of diastolic function.

We postulated that in patients with essential hypertension and normal left ventricular (LV) systolic function, left atrial (LA) size correlates with LV wall thickness by better reflecting the chronicity and duration of LA hypertension than the commonly used hemodynamic and Doppler measures of LV diastolic function. Accordingly, hemodynamic, Doppler, and two-dimensional echocardiographic measurements were performed in 30 subjects with no cardiovascular abnormalities other than essential hypertension (mean systolic blood pressure of 150 +/- 29 mm Hg). The mean LV wall thickness was 0.57 +/- 0.14 cm/m2 and the mean LV ejection fraction was 0.62 +/- 0.12. Hemodynamic and Doppler measures including pulmonary capillary wedge and LV end-diastolic pressures, isovolumic LV pressure relaxation, LV chamber elastic stiffness, and E/A ratio (E and A waves on the pulsed Doppler signal of the mitral valve) correlated poorly (r = 0.01 to -0.52) with LV wall thickness. Both E/A ratio and isovolumic LV pressure relaxation correlated better (p = 0.05) with patient age than with LV wall thickness. In contrast, LA area (in the apical four-chamber view) had a good correlation (r = 0.77 for LA area in atrial diastole and r = 0.86 for LA area in atrial systole) with LV wall thickness. Multiple regression analysis revealed LA area in atrial systole to be the best correlate of LV wall thickness. We conclude that because the left atrium is a thin-walled structure, its size may increase with an increase in LA pressure. In the absence of mitral valve disease and atrial fibrillation, LA size may reflect the chronicity and duration and thus the history of LA hypertension. LA size in the apical four-chamber view may, therefore, provide a simple noninvasive assessment of the degree of LV diastolic dysfunction.

Adult↗
PubMed2004

Determinants of cardiopulmonary functional improvement after transcatheter atrial septal defect closure in asymptomatic adults.

OBJECTIVES: We sought to evaluate the course of cardiopulmonary function after transcatheter atrial septal defect (ASD) closure and to identify the physiopathologic mechanisms leading to this change. BACKGROUND: Conflicting reports exist on cardiopulmonary functional improvement in asymptomatic adults after transcatheter closure of a secundum ASD. METHODS: Thirty-two consecutive adults (13 males; age 42.6 +/- 16.7 years) underwent maximal cardiopulmonary exercise testing and transthoracic echocardiography both on the day before and six months after transcatheter ASD closure. Mean pulmonary artery pressure, pulmonary to systemic flow ratio (Qp/Qs), and ASD diameter were measured before closure. RESULTS: Peak oxygen uptake (Vo(2)) (p < 0.001), peak oxygen pulse (p = 0.0027), and vital capacity (p = 0.0086) improved after ASD closure, although peak heart rate did not. A significant correlation was found between peak Vo(2) improvements and Qp/Qs (p = 0.0013). Left ventricular ejection fraction (LVEF) (p < 0.0001) and left ventricular end-diastolic diameter (LVEDD) (p < 0.0001) significantly increased after six months, although left ventricular end-systolic diameter did not. Right ventricular long- and short-axis dimensions decreased (both p < 0.0001). Peak Vo(2) and of peak oxygen pulse improvements correlated to both LVEF (p = 0.0009 and 0.0019, respectively) and LVEDD (p < 0.0001 and 0.032, respectively) increments. The decrease of both long- and short-axis right ventricular dimensions positively correlated to both LVEF and LVEDD improvements. The improvement in LVEF correlated to Qp/Qs (p = 0.0026). CONCLUSIONS: Transcatheter ASD closure leads to a significant improvement in cardiopulmonary function within six months, via an increase in peak oxygen pulse. An increase in both left ventricular stroke volume and cardiac output due to a positive ventricular interaction is the mechanism leading to improved peak Vo(2).

Adolescent↗
PubMed2006

[Influence of age of patients with atrial fibrillation on left atrium function].

UNLABELLED: Frequency of occurrence of atrial fibrillation (FA) increases with age. In the elderly this arrhythmia might influence the enlargement and function of left atrium (LA) and its appendage (LAA). The aim of this study was to assess the association between age of patients and selected echocardiographic parameters concerning left atrium. MATERIAL AND METHODS: 120 consecutive patients (52 women and 68 men) with FA were studied 36-89 years old (mean 68.7 +/- 10.9). Patients were divided into two groups using a cut-off value age of 70 years. Older than 70 years were 64 patients, whereas below this age were 56 persons. Duration time of arrhythmia did not differ significantly between studied groups. In all patients transthoracic (TTE) and transoesophageal (TEE) echocardiography were performed to assess selected echocardiographic parameters concerning left atrium (LA) and its appendage (LAA). During TTE were measured: LA maximal diameter in M-mode (LAmax), LA transversal diameter in 4-CH (LAtrans), LA longitudinal diameter in 4-CH (LAlong), LA circulum in 4-CH (LAcirc), LA area in 4-CH (LAarea). Consequently TEE was done to assess LAA transversal diameter (LAAtrans), LAA longitudinal diameter (LAAlong), LAA circulum (LAAcirc), LAA area (LAAarea), spontaneous echocardiographic contrast (SEC), thrombus (THR), maximal LAA outflow velocity (LAAF), maximal LAA inflow velocity (LAAB), integral of LAA outflow velocity (LAAFintg) and integral of LAA inflow velocity (LAABintg). RESULTS: LAmax (4.91 +/- 0.61 vs. 4.22 +/- 0.49), LAtrans (4.75 +/- 0.71 vs. 4.11 +/- 0.44) and LAarea (31.85 +/- 6.9 vs. 27.51 +/- 6.54) were significantly greater in older patients compared to those below 70 years old. LAlong, LAcirc, LAarea, LAA trans, LAAlong, LAAcirc did not differ between studied groups. Thrombi in LAA were detected rarely in study population and were found often in older patients (in 2 vs. 6 patients). In almost 2/3 older patients SEC in LAA was visualized, which was markedly frequent when compared to younger group. In older patients parameters characterizing LAA function had significantly lower values than in younger patients (LAAF respectively 19.8 +/- 9.16 vs. 28.57 +/- 10.7, LAAB respectively 21.6 +/- 8.12 vs. 31.81 +/- 10.88). CONCLUSIONS: In patients with atrial fibrillation left atrium and its appendage diameters are greater in the elderly. Left atrium appendage function is more deteriorated in older patients with atrial fibrillation. During atrial fibrillation thrombus formation and appearance of spontaneous echocardiographic contrast is more often in the elderly.

Adult↗
PubMed1994

Functional characterization of an ex vivo preparation of atrial myocardium from children with congenital heart defects: sensitivity to tyramine and adrenoceptor antagonists.

Small pieces of atrial tissue removed from the cannulation site before cardioplegia were used to develop a method for studying adrenergic regulation of the myocardial contractile force in children operated on for congenital heart defects (CHD). We measured the development of the isometric force of contraction dT/dtmax (T'max). Reduction in basal contractility induced by the beta-adrenoceptor antagonist timolol indicated that the myocardium was about half-maximally stimulated by endogenous norepinephrine (NE), probably released from nerve endings by the electrical stimulation. The inotropic effect of endogenous NE could be further increased by tyramine (EC50 approximately 5 microM). A maximal concentration of tyramine increased T'max by a median of 62.5% above the basal level. Sequential blockade of the beta- and alpha 1-adrenoceptors after tyramine stimulation by timolol and prazosin, respectively, indicated that a near-maximal response to combined adrenoceptor stimulation by endogenous NE was mediated by both beta-adrenoceptors (median 77%) and alpha 1-adrenoceptors (median 23%). The basal level of endogenous NE may conceal inotropic effects by exogenous alpha-agonists added to this type of preparation. This preparation is suitable for studying adrenergic regulation by reversing the effects of endogenous NE.

Adolescent↗
PubMed1998

Role of echocardiography in patients undergoing elective cardioversion of atrial fibrillation.

Echocardiography has emerged as a fundamental tool in the evaluation of patients with atrial fibrillation (AF). Transthoracic echocardiography remains a primary tool for the evaluation and management of many patients presenting with their first episode of AF, but it is not adequate for exclusion of atrial thrombi. TEE offers excellent visualization of the atria and accurate identification or exclusion of thrombi. In concert with therapeutic anticoagulation, a TEE-guided approach to early cardioversion appears to have a safety profile similar to that of conventional therapy (1 month of precardioversion warfarin). The TEE-guided approach offers the advantages of simplified anticoagulation management and shorter duration of sustained AF, thereby allowing for a more rapid recovery of atrial mechanical function. Warfarin should be continued for 1 month after cardioversion to allow for more complete recovery of atrial function and for prophylaxis should the patient revert to AF. Cost-effectiveness models demonstrate that TEE-guided cardioversion represents a cost-effective strategy, but only if the transthoracic echocardiogram is omitted. For patients with a thrombus on the initial TEE, follow-up TEE (to document thrombus resolution) is recommended before cardioversion.

Anticoagulants↗
PubMed1982

Normal left ventricular systolic function in adults with atrial septal defect and left heart failure.

Systolic left ventricular contractile function has not been extensively evaluated in patients with atrial septal defect who have symptoms of left-sided congestive heart failure. This study examined left ventricular systolic function hemodynamically and angiographically in 6 such adult patients (Group A), 12 adult patients with atrial septal defect without heart failure (Group B) and 20 normal subjects. The mean ( +/- standard error of the mean) left ventricular end-diastolic pressure was higher in patients in Group A (17 +/- 0.8 mm Hg) than in patients in group B (6.9 +/- 0.6 mm Hg) (p less than 0.001). Both right atrial pressure ( 11 +/- 1.3 versus 4.9 +/- 0.5 mm Hg) (p less than 0.001) and mean pulmonary arterial pressure (30 +/- 1.8 versus 15 +/- 1 mm Hg) were also higher in Group A than in Group B. Left ventricular cardiac index and stroke work index did not differ in the two groups. Variables of left ventricular systolic function were similar in both groups of patients and in normal subjects: Ejection fraction was 0.71 +/- 0.05 in Group A, 0.74 +/- 0.02 in Group B and 0.74 +/- 0.01 in normal subjects. Velocity of circumferential shortening was 1.38 +/- 0.14 circumferences/s in Group A, 1.38 +/- 0.07 circumferences/s in Group B and 1.27 +/-0.04 circumferences/s in normal subjects. There was no difference in left ventricular contractile function as indicated by the ratio of end-systolic wall stress to end-systolic volume index among the three groups: normal subjects, average 5.6 +/- 0.19 versus 6.1 +/- 0.5 in Group B and 6.0 +/- 0.6 dynes X 10(3)/cm(2)/(ml/m(2) in Group A. This study of patients with atrial septal defect and left heart failure indicates that abnormal left ventricular systolic contractile function is probably not the cause of the symptoms and elevated left heart filling pressures observed in this group. An abnormality in left ventricular diastolic filling, perhaps related to the volume loaded right ventricle, may explain these changes.

Adolescent↗
PubMed2004

[Concomitant treatment of atrial fibrillation in open-heart surgery patients: late rhythm and functional results].

BACKGROUND: In recent years left atrial approaches have become popular because of technical simplicity, reproducibility and minor surgical trauma compared to the standard maze procedure. We analysed mid-term results of intraoperative left radiofrequency ablation of atrial fibrillation. METHODS: From February 1998 to August 2002, 206 patients (mean age 59.1 +/- 10.2 years) scheduled for open-heart surgery underwent combined treatment of atrial fibrillation at our Institution. In 163 patients (79.1%) a standard left epicardial approach was performed while 43 patients (20.9%) needed a totally endocardial approach. RESULTS: All patients but 3 underwent mitral valve surgery (104 repair and 99 replacement). Hospital mortality was 1.9%. Actuarial freedom from atrial fibrillation was 78% at 2 years and 74% at 4 years. At 4 years survival was 94% and freedom from neurological events was 98%. All patients with stable sinus rhythm 3 months after surgery recovered biatrial contractility. CONCLUSIONS: Left radiofrequency ablation of atrial fibrillation is effective in restoring sinus rhythm and normal atrial function. Combined atrial fibrillation treatment should be considered in all patients undergoing open-heart surgery.

Actuarial Analysis↗
PubMed1993

Plasma atrial natriuretic peptide response to direct current cardioversion of atrial fibrillation in patients with mitral stenosis.

OBJECTIVES: The purpose of this study was to evaluate the effect of direct current cardioversion therapy on the plasma concentration of atrial natriuretic peptide and to determine the main factors that influence the change in plasma atrial natriuretic peptide levels in patients with atrial fibrillation. BACKGROUND: In atrial arrythmias, whether the fast atrial rate itself or the associated elevation of atrial pressure, or both, contributes to the increase in atrial natriuretic peptide is a subject of debate. METHODS: In 15 patients with mild mitral stenosis, plasma atrial natriuretic peptide levels were measured and transmitral flow pattern was obtained by continuous wave Doppler echocardiography immediately before cardioversion and at 5 min, 4 h, 24 h and 5 days after direct current cardioversion. Mean mitral pressure gradient and atrial filling fraction were calculated on the basis of transmitral flow. RESULTS: In three patients who did not have a successful return to sinus rhythm, plasma atrial natriuretic peptide levels remained elevated after cardioversion. In 12 patients who maintained sinus rhythm, plasma atrial natriuretic peptide levels were significantly reduced from 79 +/- 29 to 36 +/- 11 pg/ml 4 h after cardioversion to sinus rhythm. However, the mitral pressure gradient did not change significantly during the observation period. There were progressive increases in atrial filling fraction throughout the observation period. From 4 h to 5 days after direct current cardioversion, plasma atrial natriuretic peptide levels gradually increased concomitantly with the recovery of atrial mechanical function. CONCLUSION: The reduction of plasma atrial natriuretic peptide levels after direct current cardioversion might be due to recovery from the high rate of atrial firing and not to an alteration in the mitral pressure gradient. Direct current cardioversion itself does not seem to influence atrial natriuretic peptide secretion. The increase in atrial natriuretic peptide levels from 4 h to 5 days after cardioversion concomitantly with an increase in atrial filling fraction may be due to recovery of atrial mechanical function.

Adult↗
PubMed2005

The determinants of right ventricular function in patients with atrial septal defect.

OBJECTIVE: The purpose of this study was to ascertain the determinants of right ventricular (RV) systolic and diastolic functions in patients with atrial septal defect. METHODS: Thirty-three patients with atrial septal defect having left to right shunt were enrolled in this study. RV function parameters were assessed echocardiographically. RV systolic function was assessed using tricuspid tissue Doppler S velocity (St). With regard to RV diastolic function parameters, E/A ratio, deceleration time (DT), E/Et ratio (Et = tissue Doppler E velocity), RV isovolumetric relaxation time (RVIVRT) were assessed. RV myocardial performance index (MPI) was calculated as an index of both systolic and diastolic function. Pulmonary artery stiffness (PAS) was also calculated. After echocardiography, right and left heart catheterization was performed. Mean pulmonary artery pressure (MPAP), mean right atrial pressure (MRAP), systemic flow (Qs), pulmonary flow (Qp), systemic vascular resistance (SVR), and pulmonary vascular resistance (PVR) were obtained using the data of invasive measurements. RESULTS: In multivariate analysis, MPAP was found to be the parameter closest related to RVIVRT (r = 0.73, p < 0.001) and E/Et (r = 0.66, p < 0.001), while PAS was found to be the parameter closest related to MPI (r = 0.53, p = 0.002). In addition, St velocity was found the only parameter related to PVR (r = -0.39) in univariate analysis. There was no relationship between QP/QS and any of the RV function parameters. CONCLUSION: The pulmonary vascular bed appears to be the predictor of the RV functions in patients with atrial left to right shunts, and the amount of the shunt seems to have no direct adverse influence on the RV functions.

Adult↗
PubMed1983

Cholinergic-sympathetic interactions in the left atrium and left ventricle of conscious dogs.

The extent of cholinergic-sympathetic interaction in the heart was examined in the resting control state and after isoproterenol stimulation in eight conscious dogs. Sonomicrometer crystals and solid-state pressure transducers were implanted in the left atrium and the left ventricle to evaluate mechanical function while heart rate was held constant by atrial pacing. Edrophonium (0.5 mg/kg i.v.) was given as a single dose at rest and during increased sympathetic tone produced by continuous infusion of isoproterenol (0.08 micrograms/kg/min). In the control state, edrophonium administration caused no change in left ventricular dP/dt, fractional shortening or velocity of contraction, but produced significant (P less than .001) decreases in left atrial fractional shortening and contraction velocity. During isoproterenol infusion there were significant increases in dP/dt, the velocity of contraction and fractional shortening in both left atrium and ventricle (P less than .001). Administration of edrophonium during this increase in inotropic state produced significant (P less than .01) decreases in left ventricular dP/dt, fractional shortening and contraction velocity. Moreover, after edrophonium, left atrial fractional shortening and velocity of contraction were decreased to values that were significantly (P less than .001) less than control. Thus, cholinergic stimulation caused selective depression of left atrial systolic function at rest and depression of both left atrial and ventricular function during sympathetic stimulation.

Animals↗
PubMed2003

Left atrial and left ventricular function in healthy children and young adults assessed by three dimensional echocardiography.

OBJECTIVE: To establish normal values of left atrial and left ventricular volumes and function in children and young adults using three dimensional echocardiography (3DE). METHODS: 169 healthy subjects aged 2 to 27 years were studied by digitised 3DE. 3DE was achieved using rotational acquisition of planes at 18 degrees intervals from the parasternal view for the left atrium and from the transthoracic apical view for the left ventricle with ECG gating and without respiratory gating. Left atrial and left ventricular volumes could be calculated throughout the heart cycle, and the respective time-volume curves were reconstructed in each subject. RESULTS: For the analysis the subjects were divided into five groups according to body surface area: 0.5-0.75 m2, 0.75-1.0 m2, 1.0-1.25 m2, 1.25-1.5 m2, and over 1.5 m2. Mean (SD) left atrial maximum volume/body surface area was 19.6 (3.5), 21.7 (3.7), 22.0 (4.7), 24.5 (4.8), and 27.4 (6.4) ml/m2; left ventricular maximum volume/body surface area was 50.1 (8.8), 54.9 (10.1), 56.4 (9.9), 58.7 (11.0), and 64.4 (10.3) ml/m2. Left atrial active emptying increased from 19% to 35% with age (r = 0.34, p < 0.001) and with decreasing heart rate (r = -0.28, p < 0.001). CONCLUSIONS: Transthoracic 3DE is well suited for studying the phasic changes in left atrial and left ventricular volumes in young children as well as in adults. The data obtained from 169 healthy subjects will serve as a reference for further studies in patients with various cardiac abnormalities.

Adolescent↗