Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “atrial function”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 541 records · Page 30Linked to original sources
PubMed1989

Chronotropic function in spontaneously diabetic BB rats.

In the present study, isolated atrial function in spontaneously diabetic BB Wistar rats maintained for 12 weeks on a low (BB-LI) and a high (BB-HI) dosage of insulin was examined. Basal atrial rates were unchanged in the diabetic animals, relative to nondiabetic littermates (ND-BB) or Wistar controls. The BB-HI animals were euglycemic and responded to isoproterenol in a similar manner to the ND-BB and Wistar control animals. In contrast, BB-LI animals remained hyperglycemic and exhibited lower responses to the maximum chronotropic effects of isoproterenol. Plasma thyroid hormone levels were unaltered in the BB-diabetic animals. These results therefore reveal an absence of bradycardia and hypothyroidism in spontaneously diabetic BB rats, in contrast to previous observations in streptozotocin diabetic rats. However, a decrease in chronotropic response to isoproterenol was still noted in the BB-LI animals. These findings suggest that decreased positive chronotropic effect of isoproterenol in diabetes may not be a direct consequence of altered thyroid status.

Animals↗
PubMed2001

Clinical analysis of results of a simple left atrial procedure for chronic atrial fibrillation.

BACKGROUND: We have performed a simple left atrial procedure for eliminating chronic atrial fibrillation (AF) associated with mitral valve disease. This article analyzes the midterm results of this procedure. METHODS: Thirty-two patients were enrolled in this study concomitant with mitral valve operations. Patients were divided into two groups (AF- and AF+). We examined the efficacy of this operation and atrial function for more than 12 months of follow-up. RESULTS: In a total of 98.5 patient years of follow-up, AF was absent 3 years after operation in 74%. Of preoperative and intraoperative variables, only long duration o

Aged↗
PubMed1981

[Electrophysiological properties of acute intravenous sotalol in man].

The electrophysiological properties of of 0,6 mg/Kg SOTALOL administered intravenously were studied in 15 subjects aged between 32 and 81 years. The following parameters were recorded: sinus rate (SR), corrected sinus node recovery time (SNRT), sinoatrial conduction time (SACT), PA interval, right atrial effective refractory period (ERP), right atrial functional refractory period (FRP), AH interval at rest, at 100 bpm, Luciani-Wenckebach point (LWP), AV node ERP and FRP, HV interval, His-Purkinje ERP, right ventricular ERP, corrected QT interval. At this dosage, intravenous SOTALOL displays two types of behaviour: --That common to the betablocker drugs: slowing SR by 16%, increasing the AV nodal conduction, increasing the AH interval at rest (5%), at 100 bpm (23%), increasing AV nodal ERP (26%) and FRP (20%), decreasing the LWP (18%). --Other properties: increasing intraatrial PA interval (3%), increasing right atrial ERP (II%), FRP (I7%), increasing right ventricular ERP (8%), increasing His-Purkinje ERP (when measurable) (about 6%), no change in corrected QT interval. At this dosage, SOTALOL exhibits electrophysiological behaviour similar to drugs in Class III (Touboul): those with a "wide electrophysiological spectrum".

Adult↗
PubMed2005

The left atrial appendage, a small, blind-ended structure: a review of its echocardiographic evaluation and its clinical role.

The increasing prevalence of stroke and atrial fibrillation is a stimulus for new therapeutic strategies and also warrants a review of imaging modalities of the most important source of cardiac systemic embolic events: the left atrial appendage (LAA). This blind-ended, complex structure is embryologically distinct from the body of the left atrium and is sometimes regarded as just a minor extension of the atrium. However, it should routinely be analyzed as part of a transesophageal echocardiographic (TEE) examination. A pulsed Doppler TEE analysis of LAA emptying flow should supplement a two-dimensional (2-D) analysis; these examinations have proven to be highly reproducible and to help assess thromboembolic risk. In 2-D imaging, potential thrombus and spontaneous echo contrast should be sought. In addition, LAA plays a hemodynamic role that participates in atrial function and is influenced by various hemodynamic conditions. In view of the embolic risks from a dysfunctional appendage, the LAA is often ligated during cardiac valve surgery. New devices are under evaluation for percutaneous closure of the LAA, and further studies should improve the definition, understanding, and treatment of LAA dysfunction.

Age Factors↗
PubMed2004

Mechanism of improvement in exercise capacity after the maze procedure combined with mitral valve surgery.

OBJECTIVE: To clarify the mechanism of improvement in exercise capacity after the maze procedure. DESIGN: Retrospective study. SETTING: Tertiary referral centre. PATIENTS: 26 patients (mean (SD) age 57 (9) years) with atrial fibrillation (AF) and mitral valve disease were studied with echocardiography and cardiopulmonary exercise testing before and after the maze procedure combined with mitral valve surgery. Of these, eight had persistent AF and 18 had restored sinus rhythm (SR) by the surgery. Six patients (mean (SD) age 59 (12) years) with AF undergoing mitral valve surgery without the maze procedure who had cardiopulmonary exercise testing before and after the surgery formed the control group. MAIN OUTCOME MEASURES: Echocardiographic parameters of atrial function were measured from transmitral flow recordings. Peak oxygen uptake (VO2) and the slope of the relation between VO2 and workload (ratio of DeltaVO2 to Delta work) were determined as indices of exercise capacity. RESULTS: The degree of improvements in peak VO2 and the ratio of DeltaVO2 to Delta work after the mitral valve surgery was comparable between the maze and control group. It was also comparable between patients with and those without successfully restored SR after the maze procedure. The degree of the increase in peak VO2 correlated with the change in left atrial diameter (r = -0.40, p = 0.047) but atrial contraction did not correlate with the increase. CONCLUSIONS: Improvement in exercise capacity may not be caused by restored SR and atrial contraction but may at least partly relate to the reduction of left atrial size and improvement of haemodynamic variables by the surgery.

Adult↗
PubMed2005

Reconstitution of ventricular myosin with atrial light chains 1 improves its functional properties.

Atrial light chain 1 (ALC-1) is expressed in embryonic and hypertrophied human ventricles but not in normal adult human ventricles. We investigated the effects of recombinant human atrial light chains (hALC-1) on the structure and enzymatic activity of synthetic filaments of ventricular myosin. The endogenous ventricular myosin light chain 1 (VLC-1) was partially replaced by recombinant hALC-1 yielding hALC-1 levels of 12%, 24% and 42%. This reconstitution of ventricular myosin with hALC-1 did not change the length of synthetic myosin filaments but led to more rounded myosin heads in comparison with those of control filaments. Actin-activated ATPase activity of myosin, a parameter of functional activity of molecular motor, amounted to 79.5 nmol P(i)/mg per min in control myosin filaments. Reconstitution with hALC-1 caused a profound increase of the actin-activated myosin ATPase activity in a dose dependent manner, for example, synthetic myosin filaments formed with 12%, 24% and 42% hALC-1 reconstituted myosin revealed the actin-activated ATPase activity increased by 18%, 26% and 36%, respectively, as compared to control. These results strongly suggest that in vivo expression of ALC-1 enhances ventricular myosin function, thereby contributing to cardiac compensation.

Electrophoresis, Polyacrylamide Gel↗
PubMed1985

Pre- and postoperative electrophysiologic assessment of children with secundum atrial septal defect.

Sinus node (SN) and atrioventricular node (AVN) dysfunction after repair of atrial septal defect (ASD) may be caused by inherent nodal abnormalities and not related to altered hemodynamics. To assess the preoperative prevalence and postoperative persistence of nodal dysfunction, 21 consecutive children, mean age 5.4 years, underwent electrophysiologic evaluations before ASD repair. Preoperative SN recovery time was prolonged in 11 patients and was associated with abnormal AVN response to rapid atrial pacing in 5. There were no significant differences in age, hemodynamic values or shunt size between children with normal and those with abnormal nodal function. Atrial and AVN refractory periods were normal. The ASD was repaired in 9 children with SN dysfunction. Electrophysiologic studies performed 4 to 16 months after surgical correction showed improvement in all electrophysiologic values. However, SN function remained abnormal. Significant decreases were observed in atrial (p less than 0.05) and AVN (p less than 0.05) refractory periods, with increased atrial conduction velocity (p less than 0.01) and AVN Wenckebach response to atrial pacing (p less than 0.01). ASD repair improved nodal and atrial muscle electrophysiologic function, theoretically by relieving stress on atrial impulse propagation. SN and AVN dysfunction may persist as an inherent part of the ASD complex.

Adolescent↗
PubMed1985

[Analysis of right atrium function in patients with chronic pressure overload of the right ventricle].

Right atrial function was evaluated in 16 patients with and without chronic right ventricular pressure overload. A simultaneous right atrial pressure recording using a catheter-tip-micromanometer and right atrial volume determination using cross-sectional echocardiography were performed. The pressure-volume curve of the right atrium was composed of an a-loop and a v-loop. The ratio of active atrial emptying to right ventricular stroke volume in patients with right ventricular pressure overload was significantly larger than in the control group (36 +/- 6% vs. 23 +/- 5%, p less than 0.04). The right atrial work was also significantly greater in patients with right ventricular pressure overload (6.2 +/- 2.0 mWs) than in normal subjects (4.2 +/- 2.0 mWs, p less than 0.04). The ratio of active atrial emptying to ventricular stroke volume and right atrial work were significantly related in both control group and patients with right ventricular pressure overload (r = 0.83). Right atrial work also showed a significant linear correlation with right atrial work before active atrial emptying (r = 0.92). We conclude that in patients with right ventricular pressure overload the right atrium shows more pronounced active emptying and contributes to better diastolic filling of the right ventricle.

Angina Pectoris, Variant↗
PubMed1998

Left atrial systolic and diastolic function accompanying chronic rapid pacing-induced atrial failure.

The objective of this study was to examine the hypothesis that long-term, rapid atrial pacing produces a model of atrial systolic and diastolic dysfunction but does not alter ventricular function. Eight dogs were atrially paced at 400 beats/min (3:1-5:1 ventricular response) for 6 wk and subsequently instrumented with left atrial (LA) and left ventricular (LV) sonomicrometers and micromanometers. Data were compared with those from six sham-operated controls at matched heart rates and mean LA pressures of 10 mmHg. Dogs with rapid pacing had slightly greater LA volume (10.3 +/- 4.0 vs. 7.9 +/- 4.4 ml) and reduced ejection fraction (2.2 +/- 1.4 vs. 13.0 +/- 4.0, P < 0.05), systolic ejection rate (0.3 +/- 0.1 vs. 2.8 +/- 1.2 vol/s, P < 0.05), and reservoir fraction (0.07 +/- 0.04 vs. 0.35 +/- 0.06, P < 0.05) compared with controls. LA diastolic chamber stiffness was greater after rapid atrial pacing than before (stiffness constant kc, 5.7 +/- 2.3 vs. 3.4 +/- 0.6, P < 0.05), and the ratio of transesophageal echo-determined pulmonary venous systolic to diastolic integrated flow (a measure of relative reservoir to conduit function of the LA) was less in rapidly paced dogs compared with control dogs (0.41 +/- 0.19 vs. 0.68 +/- 0.23, P < 0.05). In contrast, rapid atrial pacing did not influence LV systolic performance or lusitropy, because the LV pressure time derivative and the time constant of LV relaxation were similar in both groups. In this model of isolated atrial myopathy, increased atrial stiffness and enhanced conduit function compensate for impaired atrial booster pump and reservoir functions.

Animals↗
PubMed2001

[Sinus node functions, sinoatrial conduction, atrial conductivity after incipient paroxysms of atrial fibrillation and flutter in patients with ischemic heart disease].

AIM: Prediction of the rate of recurrent paroxysms of atrial fibrillation (AF) and flutter (AFl) after the first arrhythmia episode; determination of relevant antiarrhythmic treatment. MATERIAL AND METHODS: 157 patients with ischemic heart disease (IHD) complicated by new episodes of AF and AFl entered the study. After the initial episode and 1-2 arrhythmia recurrences all the patients have undergone assessment of hemodynamics, atrial conduction of excitation, sinus node function using transesophageal pacing. The patients were divided into two groups: group 1 consisted of 42 patients having no recurrent paroxysms of AF or AFl for at least 6 months; 115 patients of group 2 had at least one episode of recurrent arrhythmia for 6 months after the first paroxysm. RESULTS: Patients of group 2 vs those of group 1 had a significantly longer first episode, more frequent occurrence of calcinosis of mitral and/or aortic valve, more serious systolic and diastolic dysfunctions and most frequent retrograde atrial excitation conduction after the first paroxysm. CONCLUSION: In detection of only disturbed intraatrial conduction in IHD patients after the first paroxysm of AF and AFl predicted are clinical recurrences of arrhythmia with the recurrence-free period more than 6 months. In retrograde atrial conduction of excitation combined with systolic and diastolic left ventricular dysfunction, sinus node dysfunction prognosis was made of more frequent episodes of AF and AFl.

Adult↗
PubMed2003

Factors determining left atrial kinetic energy in patients with chronic mitral valve disease.

BACKGROUND: Increased left atrial (LA) work is a major contributor to LA fatigue, LA failure and atrial fibrillation in patients with mitral stenosis (MS) and mitral valvular regurgitation (MVR). The present study was undertaken to define factors that determine LA work in patients with chronic mitral valve disease. PATIENTS AND METHODS: Peak left atrial kinetic energy (LAKE)was used as an index of LA work in 14 patients with MS, 14 with MVR, and 19 normal subjects matched for age and gender with MS and MVR patients. LA stroke volume and ejection fraction were measured from the biplane area-length method using echo techniques. Peak LAKE was obtained from the formula 1/2 mv2, where m = LA stroke volume x 1.06 (blood's specific gravity) and v = transmitral Doppler A-wave velocity. RESULTS: Stepwise regression analysis often clinical and echocardiographic parameters demonstrated that in MS, mitral valve area (r2 = 0.43) and LA maximal volume (r2 = 0.62), in MVR, only LA maximal volume (r2 = 0.42) contributed independently to LAKE. LAKE was greater in MS and MVR compared to control subjects while LA ejection fraction was similar in all groups. CONCLUSIONS: It is concluded that LA work is markedly increased in patients with chronic mitral valve disease. Increased LA work in chronic mitral valve disease may contribute to LA fatigue, LA failure, and atrial fibrillation.

Adult↗
PubMed1998

Left atrial energy in normal subjects, in patients with symptomatic mitral stenosis, and in patients with advanced heart failure.

In a population consisting of 45 subjects (15 patients with mitral stenosis, 15 patients with heart failure, and 15 normal subjects), the left atrial (LA) pressure-area relation was assessed and the correlations between LA stroke work, LA kinetic energy, and LA ejection force were studied. The area of the counterclockwise A loop expressing the LA external work was measured. LA kinetic energy was obtained from the formula: 1/2 x stroke volume x 1.06 x v2, where v = transmitral Doppler A velocity. An excellent correlation was found between LA stroke work index and LA kinetic energy when data from all patients were plotted together (r = 0.95, p <0.001). The Pearson's correlation similarity coefficient between LA ejection force and kinetic energy as well as between LA ejection force and stroke work index was r = 0.54 (p <0.001). The r value of 0.54 was significantly lower than r = 0.95 (p <0.03). LA kinetic energy extends the use of transmitral flow Doppler data to include assessment of LA work. LA work can be obtained noninvasively with a high degree of accuracy.

Atrial Function↗
PubMed2002

Surgical ablation of atrial fibrillation using the epicardial radiofrequency approach: mid-term results and risk analysis.

BACKGROUND: The minor technical and time requirements with respect to the maze operation combined with a comparable efficacy has led to an increasing popularity of left atrial approaches to treat atrial fibrillation. We report our experience with a left atrial procedure based on extensive use of epicardial radiofrequency ablation in an effort to minimize cardiac arrest time. METHODS: A total of 132 consecutive patients with atrial fibrillation (121 chronic, 11 paroxysmal) undergoing open heart surgery had combined intraoperative ablation. An original set of left atrial lesions was performed using a radiofrequency linear catheter. Most of the ablations were performed epicardially before aortic cross-damping. Patients with contraindications to the epicardial approach had the whole lesion set performed endocardially. RESULTS: The mean cardiac arrest time spent for open heart ablations was significantly shorter (5.2 +/- 0.9 minutes with modem catheters) when the epicardial approach was used (107 of 132 patients, 81%). Hospital mortality was 0.8%. Freedom from atrial fibrillation was 77% 3 years after the operation. Of all the variables analyzed, only age at surgery and early postoperative arrhythmias increased the risk of recurrent atrial fibrillation. Overall 3-year survival was 94%. The 3-year actuarial freedom from stroke was 98%. No patient required implantation of a permanent pacemaker. Atrial contractility was recovered in all patients with stable sinus rhythm. CONCLUSIONS: Left atrial radiofrequency ablation allows recovery of sinus rhythm and atrial function in the great majority of patients with atrial fibrillation who undergo open heart surgery. The epicardial radiofrequency approach is a safe and effective means to cure atrial fibrillation with negligible technical and time requirements.

Atrial Fibrillation↗
PubMed2004

Cox/Maze III operation versus radiofrequency ablation for the surgical treatment of atrial fibrillation: a comparative study.

BACKGROUND: The purpose of this study was to evaluate the efficacy of radiofrequency (RF) ablation in the treatment of atrial fibrillation, by comparatively analyzing the outcomes of the patients who underwent RF ablation with those of patients who underwent Cox/Maze III surgery. METHODS: Between April 1995 and June 2002, 70 patients underwent surgery for atrial fibrillation and open-heart surgery at the Department of Cardiovascular Surgery of the University of Bologna: 30 patients underwent the surgical Cox/Maze III procedure (group 1), and 40 patients underwent the RF ablation according to the Maze III configuration at least on the left atrium (group 2). There were 14 males and 56 females, with a mean age of 61.5 +/- 12.5 years (range 22 to 80 years old). RESULTS: Groups 1 and 2 did not differ in terms of baseline characteristics. The perioperative mortality rate was not significantly different between the two groups (6.6% in group 1 vs 7.5% in group 2). The overall cumulative rates of sinus rhythm were 68.9% in group 1 and 88.5% in group 2 (not statistically significant). Biatrial contraction was assessed by transthoracic echocardiography in 70.4% of the patients in group 1 and 76.5% of the patients in group 2 (p = 0.65). CONCLUSIONS: The RF ablation procedure offers as good results as the Cox/Maze III operation, allowing recovery of the sinus rhythm and atrial function in the great majority of patients with atrial fibrillation who underwent open heart surgery; it is a safe and effective means of curing atrial fibrillation with negligible technical and time requirements.

Atrial Fibrillation↗
PubMed2003

Surgery for atrial fibrillation using radiofrequency catheter ablation.

OBJECTIVE: We present the results obtained in 40 patients with chronic atrial fibrillation using direct intraoperative radiofrequency to perform atrial fibrillation surgery. METHODS: Between April 2001 and June 2002, 40 patients underwent surgery for atrial fibrillation using radiofrequency ablation and cardiac surgery at the Department of Cardiovascular Surgery of the University of Bologna [corrected]. There were 8 men and 32 women with a mean age of 62 +/- 11.6 years (range: 20 to 80 years). RESULTS: Concomitant surgical procedures were: mitral valve replacement (n = 13), mitral valve replacement plus tricuspid valvuloplasty (n = 11), combined mitral and aortic valve replacement (n = 8), and combined mitral and aortic valve replacement plus tricuspid valvuloplasty (n = 5). Moreover, 1 patient underwent tricuspid valvuloplasty plus atrial septal defect repair, another required aortic valve replacement plus coronary artery bypass graft, and a third underwent aortic valve replacement. After the mean follow-up time of 16.5 +/- 2.5 months survival was 92.8% and the overall cumulative rate of sinus rhythm was 88.5%. CONCLUSIONS: We conclude that the radiofrequency ablation procedure is a safe and effective means of curing atrial fibrillation with negligible technical and time requirements, allowing recovery of the sinus rhythm and atrial function in the great majority of patients with atrial fibrillation who underwent cardiac surgery (88.5% of our study population).

Adult↗
PubMed1999

Role of genomic mechanisms on cAMP-dependent positive inotropism in isolated left atrium of rat.

It is well known that beta-adrenoceptor stimulation induces positive inotropism by cAMP-dependent phosphorylation of cardiac calcium channels. Furthermore, hypertrophy of different tissues including the heart have been related to the stimulation of these adrenoceptors via mechanisms coupled to activation of transcription and protein synthesis. Early effects of isoproterenol mediated via this pathway has also been associated to the stimulation of beta-adrenoceptors. However, the effects on the inotropism through genomic mechanisms have not yet been described. Isoproterenol (3 nM to 3 microM) induced a concentration-dependent positive inotropism, in isolated left atrium of male Wistar rats electrically stimulated (0.5 Hz, 5 ms, 30-50% above the threshold voltage), which was antagonized by atenolol (1 microM) and inhibited by a protein kinase A inhibitor, (R)p-cAMPS (10 microM). The inhibitor of transcription, actinomycin D (4 microM), and the protein synthesis inhibitor, cycloheximide (35.5 microM), significantly decreased the positive inotropism induced by isoproterenol. Forskolin (0.1 to 3 microM), an activator of adenylyl cyclase, induced a concentration-dependent positive inotropism which was also inhibited by (R)p-cAMPS, actinomycin D and cycloheximide. In the left atrium of rat, isoproterenol induced a positive inotropism which seems, at least in part, dependent upon intact transcription and protein synthesis, as suggested by the fact that the response was inhibited by the incubation with actinomycin D and cycloheximide. In addition, this genomic effect seems to be mediated by a cAMP-dependent mechanism. As it was inhibited by a protein kinase A inhibitor ((R)p-cAMPS) and similarly to isoproterenol, the positive inotropism induced by forskolin, which increases cytosolic cAMP, was also inhibited by actinomycin D and cycloheximide.

Adrenergic beta-Agonists↗
PubMed1999

Effects of hirsutine and dihydrocorynantheine on the action potentials of sino-atrial node, atrium and ventricle.

The effects of hirsutine, an indole alkaloid from Uncaria rhynchophylla MIQ. JACKSON with antihypertensive, negative chronotropic and antiarrhythmic activity, and its C3 structural epimer, dihydrocorynantheine, on membrane potentials of rabbit sino-atrial node and guinea-pig right ventricle and left atrium were studied with microelectrode techniques. In sino-atrial node preparations, hirsutine and dihydrocorynantheine (0.1 microM to 10 microM) concentration-dependently increased cycle length, decreased slope of the pacemaker depolarization (phase 4 depolarization), decreased maximum rate of rise and prolonged action potential duration. In atrial and ventricular preparations, both compounds (0.1 microM to 30 microM) concentration-dependently decreased maximum rate of rise and prolonged action potential duration. These results indicate that hirsutine and dihydrocorynantheine have direct effects on the action potential of cardiac muscle through inhibition of multiple ion channels, which may explain their negative chronotropic and antiarrhythmic activity.

Action Potentials↗