Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Atrial Function, Left”

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 1,405 records · Page 78Linked to original sources
PubMed2005

Endocardial radiofrequency ablation during mitral valve surgery: effect on cardiac rhythm, atrial size, and function.

BACKGROUND: Restoration of sinus rhythm is thought to lead to a reduction in left atrial size and to recovery of atrial contraction. We aimed to investigate changes in atrial size and function in patients undergoing radiofrequency ablation for atrial fibrillation during mitral valve surgery. METHODS: In a prospective study, 70 patients (64 +/- 10 years) with mitral valve disease and atrial fibrillation underwent mitral surgery and left atrial endocardial radiofrequency ablation. Evaluation was achieved before surgery, at 7 days, 5 months, and 22 months after surgery. Maximal right and left atrial areas, left atrial diameter, and volume were measured. Atrial filling fraction (ventricular filling related to atrial contraction to total ventricular filling ratio) was used as an index of atrial contraction. RESULTS: At the end of follow-up (22 +/- 10 months) most patients (91%) were in sinus rhythm. Actuarial freedom from atrial fibrillation recurrence was 62.5% after 2 years. Atrial size decreased, with a significant improvement in right (36 +/- 15 vs 10 +/- 20% preoperatively, p < 0.0001) and left (25 +/- 12 vs 7 +/- 14%, p < 0.0001) atrial filling fraction. Despite similar preoperative atrial size, at the end of follow-up atrial fibrillation recurrence was associated with a higher left atrial volume than in patients free of recurrence (41 +/- 14 vs 32 +/- 9 mL/m2, p = 0.004). Independent predictors of atrial fibrillation recurrence were previous mitral procedure (p = 0.029), left ventricular ejection fraction (p = 0.033), and mitral rheumatic lesion (p = 0.034). CONCLUSIONS: Left atrial radiofrequency ablation for atrial fibrillation during mitral surgery is an effective procedure restoring sinus rhythm. Right and left atrial size was significantly reduced, with a recovery in atrial contraction.

Adult↗
PubMed1995

Primary neural involvement in renal haemodynamic and functional responses to prolonged stimulation of atrial receptors in anaesthetized dogs.

To determine the precise contributory role of neural and humoral factors in the efferent mechanism of the atrial receptor-renal reflex, we have examined the effects of prolonged (45 min) stimulation of left atrial receptors on renal haemodynamics and function simultaneously in both kidneys (right kidney intact and left kidney denervated) of anaesthetized dogs. Aortic pressure in these dogs was held constant by means of an arterial reservoir connected to the aorta; heart rate changes were prevented by blocking beta 1-adrenoceptor activity with atenolol (2 mg kg-1 i.v.). Localized stimulation of atrial receptors in six dogs increased renal blood flow (6 +/- 2%), creatinine clearance (11 +/- 4%), urine flow (9 +/- 3%), sodium excretion (14 +/- 7%) and osmolal excretion (10 +/- 4%), and decreased free water clearance (14 +/- 7%) in intact kidneys, but led to no changes in denervated kidneys. In an additional four dogs, cooling the vagus nerves to 6-7 degrees C or cutting them in the neck abolished the renal responses to stimulation of atrial receptors in these stabilized preparations. These data clearly demonstrate that the renal responses to prolonged stimulation of atrial receptors are primarily mediated via myelinated vagal afferents and renal sympathetic efferents.

Animals↗
PubMed1978

Human atrial noradrenaline content, hypothermic ischaemic arrest and parameters of left ventricular function.

The noradrenaline (NA) content in tissue excised from the right atrium before and after hypothermic ischaemic arrest and subsequent coronary reperfusion was estimated biochemically and histochemically. The series consisted of 22 patients suffering from aortic valve disease. The NA concentration in the preoperative and postoperative samples was similar in all instances and it was clear that the right atrial myocardial NA content remained unchanged under conditions typical of an aortic valve replacement operation. The mean NA contents (microgram/g +/- SD) of the whole series before and after procedure were 2.0 +/- 1.1 and 2.2 +/- 1.5, respectively (p greater than 0.1 NS). Additionally, left heart catheterization was performed preoperatively in 11 patients with aortic valve disease, and certain left ventricular cardiocirculatory variables of contractility and failure were recorded. No statistically significant correlation could be found between the right atrial myocardial NA content and the left ventricular contractile state. However, left ventricular end-diastolic pressure presented a significant positive correlation with the NA content of right atrial myocardium (r = 0.65, p less than 0.02, n = 11). The problems encountered in weaning the heart off perfusion after aortic surgery can hardly be explained in terms of altered myocardial NA stores.

Adult↗
PubMed2003

Obstructive sleep apnea and the recurrence of atrial fibrillation.

BACKGROUND: We tested the hypothesis that patients with untreated obstructive sleep apnea (OSA) would be at increased risk for recurrence of atrial fibrillation (AF) after cardioversion. METHODS AND RESULTS: We prospectively obtained data on history, echocardiogram, ECG, body mass index, hypertension, diabetes, NYHA functional class, ejection fraction, left atrial appendage velocity, and medications in patients with AF/atrial flutter referred for DC cardioversion. Forty-three individuals were identified as having OSA on the basis of a previous sleep study. Data regarding the use of continuous positive airway pressure (CPAP) and recurrence of AF were obtained for 39 of these patients. Follow-up data were also obtained in 79 randomly selected postcardioversion patients (controls) who did not have any previous sleep study. Twenty-seven of the 39 OSA patients either were not receiving any CPAP therapy (n=25) or were using CPAP inappropriately (n=2). Recurrence of AF at 12 months in these 27 patients was 82%, higher than the 42% recurrence in the treated OSA group (n=12, P=0.013) and the 53% recurrence (n=79, P=0.009) in the 79 control patients. Of the 25 OSA patients who had not been treated at all, the nocturnal fall in oxygen saturation was greater (P=0.034) in those who had recurrence of AF (n=20) than in those without recurrence (n=5). CONCLUSIONS: Patients with untreated OSA have a higher recurrence of AF after cardioversion than patients without a polysomnographic diagnosis of sleep apnea. Appropriate treatment with CPAP in OSA patients is associated with lower recurrence of AF.

Aged↗
PubMed1989

Prevalence and mechanisms of mitral regurgitation in the absence of intrinsic abnormalities of the mitral leaflets.

Two hundred nineteen consecutive patients referred for echocardiography were analyzed to determine the occurrence of mitral regurgitation (MR) in the absence of intrinsic abnormalities of the mitral leaflets. MR was assessed by means of the pulsed-Doppler technique. There was a higher incidence of MR associated with absence of mitral leaflet abnormalities compared to the presence of these abnormalities (59% vs 41%, p less than 0.01). The most common causes of MR were mitral annular calcification (MAC) and incomplete mitral leaflet closure (IMLC). The extent of calcific deposit in patients with MAC and the distance from the mitral leaflet coaptation point to the mitral annular plane in systole patients with IMLC correlated well with the severity of MR by Doppler technique (rho = 0.91 and 0.71, respectively). To determine the mechanisms of MR in these two conditions, 29 consecutive patients with MAC and 28 with IMLC were referred to the echocardiography laboratory, and 10 age-matched control subjects were prospectively analyzed. Patients with MAC had a 50% reduction in the sphincteric action of the mitral anulus in systole compared to control subjects. All patients with IMLC had poor left ventricular systolic function; most had left ventricular, mitral annular, and left atrial dilation, and only eight had regional wall motion abnormalities. When discriminant function analysis was used, poor left ventricular systolic function was the principal variable that separated patients with IMLC from normal subjects (F = 81.6, p less than 0.0001). We conclude that: (1) MR in adults occurs most commonly in the absence of intrinsic abnormalities of the mitral leaflets, primarily those resulting from MAC and IMLC; (2) MR in patients with MAC results from a reduced sphincteric action of the mitral anulus in systole; and (3) IMLC results from poor left ventricular systolic function, irrespective of the cause.

Aged↗
PubMed2000

How the left and right sides of the heart, as well as pulmonary venous drainage, adapt to an increasing degree of head-up tilting in hypertrophic cardiomyopathy: differences from the normal heart.

OBJECTIVES: We aimed to assess the differences in the adaptive response of patients with hypertrophic cardiomyopathy (HCM) compared with normal subjects, as well as any association with increased susceptibility to the test. BACKGROUND: Diastolic function contributes importantly in the adaptation of the normal heart to head-up tilting. This mechanism may be disturbed by an impaired relaxation in HCM. METHODS: Twenty-one male patients with HCM (46 +/- 6 years old) and 22 healthy men (44 +/- 8 years) were studied using Doppler echocardiography after 1 and 10 min of head-up tilting at 20 degrees, 40 degrees and 60 degrees. RESULTS: In control subjects, tilting was associated with 1) a predominance of diastolic pulmonary venous flow and early left ventricular (LV) filling (atrium functioning as an open conduit); 2) right ventricular (RV) shrinkage; and 3) no LV dimensional variations. In patients with HCM, tilting was associated with 1) a prevalence of systolic pulmonary venous flow (atrium functioning as a reservoir in which filling depends on atrial relaxation and compliance) and late diastolic transmitral flow (atrium working as a booster pump); 2) LV shrinkage; and 3) no RV dimension variations. These mechanisms did not prevent stroke volume (SV) from decreasing at 40 degrees and 60 degrees in both groups. Because of a lower increase in heart rate (HR), a reduction in cardiac output (CO) was greater in patients with HCM. The responses were similar after 1 and 10 min of tilting in control subjects, whereas in patients, blood pressure (BP), SV and LV dimension fell more after 10 min. CONCLUSIONS: Adaptation of the normal heart to tilting is based on a ventricular interaction and LV diastolic properties; HCM relies on left atrial diastolic and systolic functions. An inadequate HR reaction to a fall in BP and SV in HCM (depressed reflexogenic activity) contributes to making CO more vulnerable by greater and more prolonged displacements.

Adaptation, Physiological↗
PubMed2003

Percutaneous transvenous mitral commissurotomy in juvenile mitral stenosis.

OBJECTIVE: To determine the efficacy and safety of percutaneous transvenous mitral commissurotomy (PTMC), using multi-track double balloon technique in juvenile mitral stenosis. DESIGN: Open non-randomised intervention. SETTING: Cardiac catheterisation laboratories of The Mater Hospital, The Nairobi Hospital and Kenyatta National Hospital from 1996 to 2001. PATIENTS: Forty five consecutive patients aged less than 21 years with severe pure mitral stenosis and suitable mitral valve apparatus (leaflets, chordae and papillary muscles) for successful commissurotomy. INTERVENTION: Percutaneous transvenous mitral commissurotomy under local anaesthesia. Standard left and right heart catheterisation for mitral valve disease. Trans-septal left atrial entry using standard septal puncture technique and left ventricular position secured by super-stiff guide-wire. Double-balloon mitral valvotomy on single guide-wire using multi-track balloon catheters. MAIN OUTCOME MEASURES: Mitral valve area, left atrial pressures, mitral regurgitation grade, NYHA functional class. RESULTS: Mitral valve area increased from 0.6 +/- 0.19 cm2 to 1.9 +/- 0.19 cm2 (p<0.001), left atrial pressures from 30.5 +/- 3.9 mmHg to 11.5 +/- 3.8 mmHg (p<0.001). Most patients NYHA functional class immediately improved from class III-IV to class I-II. There was no significant changes in grades of mitral regurgitation or significant complications related to the procedure. CONCLUSIONS: PTMC in juvenile mitral stenosis using the multi-track technique is safe and effective yielding satisfactory immediate results.

Adolescent↗
PubMed1998

Effects of propionyl-L-carnitine on cardiac dysfunction in streptozotocin-diabetic rats.

The effects of orally administered propionyl-L-carnitine on cardiac dysfunction in rats with streptozotocin-induced diabetes were investigated. Wistar male rats were divided into four groups: untreated normal, propionyl-L-carnitine (daily for 4 weeks with 3 g/kg orally) -treated normal, untreated diabetic, propionyl-L-carnitine-treated diabetic. Four weeks after streptozotocin administration, plasma lipid levels were increased and myocardial carnitine content was decreased in untreated diabetic rats. These changes were significantly reversed by the propionyl-L-carnitine treatment. Assessment of cardiac function with isolated perfused working hearts revealed a depression of left ventricular developed pressure as well as both maximum positive and negative dP/dt in untreated diabetic as compared with that in normal hearts. Cardiac function at the higher left atrial filling pressures in the propionyl-L-carnitine-treated diabetic rats was improved significantly compared to that in untreated hearts. The data thus suggest that oral administration of propionyl-L-carnitine can reduce abnormalities of cardiac function, correlated with a significant increase in myocardial carnitine content and improved lipid metabolism in terms of lowered plasma lipids.

Administration, Oral↗
PubMed1995

Mechanism of mitral leaflet excursion.

The factors that influence the extent of mitral leaflet opening (MLO) and closure (MLC) have not been defined. We hypothesized that left ventricular (LV) systolic function determines the rate of increase of the early diastolic left atrial (LA)-LV pressure gradient, which is responsible for the extent of MLO, and also the rate of change of the early systolic LV-LA pressure gradient, which determines the degree of MLC. Accordingly, global LV function was changed by altering left main coronary artery flow with LA pressure held relatively constant. LV end-systolic dimension and peak positive LV rate of pressure development (dP/dt) correlated best with the degrees of MLO and MLC, with average correlation coefficients of 0.88 and 0.68, and 0.86 and 0.72, respectively. Although transsecting the submitral apparatus resulted in flailing of the mitral leaflets during normal LV systolic function, the extents of MLO and MLC during LV systolic dysfunction were still influenced by LV systolic function. It is concluded that LV systolic function determines the extent (both opening and closure) of mitral leaflet excursion.

Animals↗
PubMed1996

Long-term cardiovascular effects of growth hormone treatment in GH-deficient adults. Preliminary data in a small group of patients.

OBJECTIVE: The long-term cardiovascular effects of GH administration in adults are of major clinical importance, given the increasing use of such treatment. We have evaluated long-term cardiovascular effects of recombinant human GH (rhGH) substitution in GH deficient men. DESIGN: S.c. rhGH 0.5 U/kg/week or placebo was administered in a 6-month double-blind, cross-over study, followed (after a year without substitution) by a 42-month period of open GH substitution. PATIENTS: We evaluated 7 GH-deficient men serially and compared the results with 21 men matched in terms of age and height. MEASUREMENTS: Investigations included exercise tests and Doppler-echocardiography to determine exercise capacity and cardiovascular performance. RESULTS: Heart rate and systolic blood pressure at rest increased with GH substitution to the level of the controls, as did diastolic blood pressure after an initial reduction. Age-adjusted exercise capacity increased during the study and we found no evidence of ischaemic heart disease on exercise ECG. Stroke volume increased with GH substitution, thereby normalizing the initially reduced cardiac index. There was no significant change in left atrial or ventricular internal dimensions, systolic function as measured by fractional shortening, or diastolic function as measured by isovolumic relaxation time and left ventricular filling (A/E ratio). However, a lower atrial emptying index than that seen among controls might indicate some diastolic disturbance and there was a definite increase in left ventricular wall thickness compared with controls (to 25.1 +/- 1.5 vs 19.7 +/- 0.4 mm, P < 0.001). CONCLUSIONS: We found that GH substitution in GH-deficient adults had a beneficial effect on physical performance and cardiac output. The concomitant increase in left ventricular mass index might be an effect of an excessive substitution dose.

Adult↗
PubMed2004

Randomized trials for selective site pacing: do we know where we are going?

Clinical evidence is accumulating that pacing from traditional right-sided sites (right ventricular apex and right atrial appendage) may be associated with long-term detriment to left ventricular function and promotion of atrial arrhythmias. Large numbers of small studies, some randomized, have addressed the effects of pacing from nontraditional or alternate sites, but the studies have varied in design such that comparison of results is often difficult. Many studies show data from acute studies only, although more recently longer-term data have started to become available; definition and description of pacing site also varies, adding further to the difficulties in comparing data. This article attempts to examine the randomized studies available to date, and to consider how future studies may contribute to our understanding of the effects of pacing from traditional and selected, specific sites on the right side of the heart.

Cardiac Pacing, Artificial↗
PubMed1993

Transesophageal echocardiography in congenital heart disease in the adult.

Progress achieved during the last three decades in medical and surgical treatment of infants and children with congenital heart disease has resulted in a significant number of patients surviving to adulthood. The complexity of the basic malformations in addition to the superimposed surgical interventions makes accurate diagnostic imaging essential. The scope of information obtainable from high-quality TEE supports its use in the follow-up of operated and unoperated adult patients, as well as in surgical and interventional procedures. Application of the segmental analysis of anatomy is as important during TEE as it is during TTE. Supplemental transthoracic 2-D and spectral Doppler flow measurements may be needed when poor beam alignment during TEE precludes accurate gradient determinations. Although, to date, most reports of TEE in patients with congenital heart disease have involved children and adolescents, the informational advantage is potentially greater in older adolescents and adults in whom transthoracic windows are frequently limited. In our experience with 125 TEE studies in adult patients with congenital heart disease (the majority using a biplane probe), horizontal plane TEE imaging provided important additional information concerning pulmonary venous connections, atrial baffle function, atrioventricular anatomy and function, left ventricular outflow tract lesions, and great artery positional relationships. Vertical plane TEE enhances imaging of systemic and pulmonary venous connections, atrial situs, venosus atrial septal defects, atrioventricular anatomy and function, and the ventricular septum and outflow tracts and is essential for complete assessment of complex right ventricular outflow tract anatomy, ventriculoarterial alignment, and the sizing of all aortic segments in coarctation of the aorta.

Adult↗
PubMed1989

[Changes in the level of plasma atrial natriuretic factor in patients with chronic renal failure].

Changes of plasma atrial natriuretic factor (ANF) levels in 89 patients with different kinds of renal diseases (including 39 patients treated with hemodialysis) were studied. The results showed: 1. The mean value of plasma ANF level was significantly increased in patients with renal diseases than that in healthy subjects. The increase was positively correlated with the change of creatinine, serum potassium, mean arterial pressure and ptfV1. The plasma ANF level was markedly decreased after hemodialysis. 2. The right atrial pressure of 8 patients with chronic renal failure measured by right heart catheterization was normal. No significant changes occurred after hemodialysis. 3. Impedance cardiogram and mechanical cardiogram showed that left heart function was significantly improved after hemodialysis. 4. ANF was detected in ultrafiltration liquid. 5. There was no difference of the ANF content between the serum of the first and maintenance hemodialysis. The authors thought that the main causes of increase of plasma ANF level are decrease of catabolic metabolism in renal failure, stimulation of ANF secretion by left heart failure and increased loading of left atrium and increased production of ANF by body compensation as the result of mean arterial pressure increase. The decrease of ANF after hemodialysis was mainly due to improvement of renal and cardiac function, lessening of the left atrial loading, the reduced mean arterial pressure and its direct elimination by hemodialysis.

Adolescent↗
PubMed1987

[Effects of the level of polyunsaturated fatty acids of the diet on the functioning and depletion of energy substrates in the rat heart during perfusion by left atrial route].

The effects of semi-liquid diets containing 6.6% in weight of refined sunflower seed oil (SSO) or hydrogenated coconut oil (HCO) on cardiac endogenous substrates and functional parameters of rats hearts were compared to a standard laboratory chow during seven days. No difference appeared for cardiac glycogen and lipid constituents. Cardiac performance, measured through left atrial perfusion was enhanced by SSO diet and HCO one altered it. A significative phospholipid depletion appeared during the 45 minutes perfusion only in the HCO group.

Animals↗
PubMed1991

Echocardiography of dilated cardiomyopathy in children.

Echocardiography is useful and reliable in the diagnosis and management of children with dilated cardiomyopathy. M-mode echocardiography provides quantitative information of left ventricular and left atrial dimensions and left ventricular wall thickness. Left ventricular function including shortening fraction, mean velocity of circumferential fiber shortening (V cf), systolic time intervals, left ventricular wall thickening and thinning rate, isovolumic contraction time, and wall stress can be derived from M-mode study. Left ventricular and left atrial dimensions are usually 1.5 times normal. Left ventricular systolic function is markedly reduced. Shortening fraction can be easily obtained and is the most informative index for assessing the severity of illness. Very low shortening fraction at presentation and follow-up (12-15%) is a poor prognostic sign. Two-dimensional echocardiography is valuable for excluding valvular lesion or coronary artery anomaly and detection of intracardiac thrombus. The left ventricular free wall is usually more severely affected than the ventricular septum as seen by two-dimensional echocardiography.

Cardiomyopathy, Dilated↗
PubMed2001

The prognostic significance of atrial arrhythmias recorded early after cardioversion for atrial fibrillation.

In a substantial number of patients, AF recurs after successful electrical cardioversion. The purpose of this study was to investigate if the atrial arrhythmias recorded immediately after cardioversion are associated with the risk of recurrence of the arrhythmia and to compare the prognostic significance of this parameter with that of other established risk factors. In a series of 71 patients, the risk factors for recurrence of AF during the first year after successful electrical cardioversion were analyzed. A new parameter that was investigated was the frequency of atrial premature beats and the presence of runs of supraventricular tachycardia in the Holter recording started immediately after the cardioversion. Age, left atrial size, left ventricular systolic function, duration of the arrhythmia before cardioversion, underlying cardiac disease, or medication taken were not found to be predictive of recurrence of the arrhythmia. However, the natural logarithm of the number of atrial premature complexes per hour of the Holter recording in the 37 patients in whom AF recurred was higher compared to that of the 34 patients who maintained sinus rhythm (P < 0.0005). The same was true if only the first 6 hours of the recording were analyzed (P < 0.0005). There was a trend for more frequent arrhythmia recurrence if runs of supraventricular tachycardia were present. The finding of > 10 atrial premature complexes per hour in the recording had a relative risk of 2.57 (1.51-4.37), a positive predictive accuracy of 76.5%, and a negative predictive accuracy of 70.3% for subsequent arrhythmia recurrence. We can conclude that frequent (> 10/hour) atrial premature complexes in the Holter recording after electrical cardioversion for AF is a significant risk factor for recurrence of the arrhythmia.

Arrhythmias, Cardiac↗