PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Atrial Function”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

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

At least 55 records · Page 3Linked to original sources
PubMed1978

Clinical value of tests of sino-atrial function.

Sinus node recovery times and the premature atrial stimulus test were studied in 36 patients, seven with gross sinus node disease, 25 with possible sinus node disease and four with no clinical evidence of sinus node disease. The corrected sinus node recovery time proved of most value in predicting which patients needed and would benefit from permanent pacemaker implantation, though there was one false negative diagnosis and two patients with abnormal corrected sinus node recovery times were asymptomatic. The premature atrial stimulus test usually proved to be of no practical value once severe sinus node disease was present and, in the group of patients with suspected sino-atrial disease, only 13 of 25 graphs could be analysed due to gross "scatter" in the others. When patients with symptoms have unequivocal evidence of sino-atrial dysfunction, invasive study seems unnecessary. With lesser degrees of sino-atrial disease, premature atrial stimulation may provide confirmatory evidence; but when sinus arrhythmia, atrial escape beats, or more marked dysfunction are present, one is likely to encounter useless "scatter" graphs. In the absence of regular sinus rhythm on the ECG, overdrive sinus node suppression in the only invasive study worth attempting.

Adolescent↗
PubMedDate not supplied

Remnant atrial function in human and animal recipients of a total artificial heart.

The native atria remains intact after total artificial heart (TAH) implantation. The electrical activity of the recipient's atria can be recorded from wires placed during TAH implantation. Regulating TAH heart rate by coupling it with native atrial activity has the potential for a more physiologically responsive TAH. The reactivity of the atrial impulse rate is a critical component of this link, but little is known about atrial responsiveness after TAH placement. Two human and three animal TAH recipients had recordable atrial electrical activity. Human atrial impulse rate after TAH was relatively constant at rest but unresponsive to physiologic stimuli. Analysis of human atrial contraction provided no discernable effect on ventricular filling. Animal atrial impulse rate at rest was more rapid than calves without a TAH. The bovine TAH recipients had an atrial impulse rate that responded to catecholamine stimulation and blockade. Isoproterenol caused a significant rise in atrial impulse rate (152 +/- 16 impulses per minute to 216 +/- 24 impulses per minute; p < 0.05) and propranolol caused a decrease in atrial impulse rate (142 +/- 20 impulses per minute to 122 +/- 19 impulses per minute; p > 0.05). Despite beta blockade, the atrial impulse rate remained abnormally elevated secondary to unknown factors. Animal atrial contraction did appear to intermittently augment TAH ventricular filling. These data indicate that the atria remains electrically intact after TAH implantation. The human atrial impulse rate was unresponsive to physiologic stimuli although the animal atrial impulse rate was affected by exogenous catecholamine administration, but the rate remained abnormally rapid.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Significance of right atrial function during right sided inotropic stimulation of pig hearts in situ.

Cardiac adjustments to inotropic stimulation of the right side of the heart were examined in anaesthetised, open chest pigs by calcium chloride infusion (80 mumol.min-1) into the right coronary artery. At stable haemodynamic conditions and at constant heart rate, right ventricular (RV) pre-ejection segment length increased by 4.6 (2.7-7.2) % (median, 95 % confidence interval) (p less than 0.01), RV end diastolic pressure rose from 5.3 (3.4-7.7) to 6.0 (3.6-8.8) mm Hg (p less than 0.05), and stroke volume rose by 6.8 (4.2-10.8) % (p less than 0.001). When the effect of right atrial contraction on RV filling was excluded by simultaneous pacing of atria and ventricles, the RV pre-ejection segment length no longer increased, and stroke volume rose by only 3.5 (0.1-9.5) % (p less than 0.05) during right side inotropic stimulation. Right atrial inotropic stimulation improves right ventricular filling, and may cause redistribution of blood from the systemic to the pulmonary circulation. This redistribution would raise the pulmonary vascular pressures, and thereby also improve left ventricular filling. The improved right ventricular filling partly accounts for the rise in RV output.

Animals↗
PubMed1991

Renal excretory function, atrial natriuretic peptide (ANP) and plasma renin activity (PRA) during long-term sodium loading in rats.

The effect of chronic sodium loading on the level of plasma atrial natriuretic peptide (ANP) and on plasma renin activity (PRA), as well as on the renal excretory function was studied. Fifty-six standardly bred Long Evans rats were divided into three experimental groups: controls, rats drinking 170 mmol NaCl/l solution instead of water, and rats consuming food with high sodium content (850 mmol NaCl/kg) for 21 days. During the study, we measured the amount of fluid intake, the parameters of the renal function: diuresis (VU); sodium, potassium and cloride excretion (UNa V, UKV and UClV), and the dynamics of body mass. On the 21st day the animals were sacrificed by decapitation. Plasma ANP and PRA were determined radioimmunologically. Packed cells volume and plasma Na and Cl concentrations were measured. The data showed a full compensation in sodium balance: the body mass dynamics in the three groups was similar; no changes in packed cells volume and plasma electrolytes were seen; UNaV and UClV were significantly increased in the groups with high sodium intake. PRA was significantly depressed in the two groups while ANP did not show any real changes. We concluded that it is PRA and not ANP that might participate in the regulation of chronic sodium balance.

Animals↗
PubMed1978

[Evaluation of sino-atrial function using the method of extrasystole induced by constant-relative premature impulses. 2. Application in 50 normal and abnormal studies].

The total immediate sino-atrial conduction time (SACT) as calculated by constant relative pacing, 40 or 50% of the immediate sinus cycle (SC), normally varies inversely with the SC. 50 patients were investigated by this method. In 38 patients without sino-atrial block (SAB) on the surface ECG, it was found that the mean slope of correlation between SACT and SC varied with the shape of the curve of Strauss and with the presence or absence of a post-pacing depression. The smallest slope was found in the group in which the curve of Strauss was horizontal in zone II, and in which there was no depression. In the groups with a rising zone II, comparative use of pacing with a fixed relationship in milliseconds suggested a phenomenon of decreasing retrograde conduction. In cases with sinus arrhythmia and a Strauss curve with scattered coordinates, the relationship between SACT and SC was maintained. 1st degree right-sided SAB should therefore be defined as a function of the immediate SC. In 12 other patients with SAB on the surface ECG, the immediate SACT was greatly lengthened so as to be immeasurable, and bore no relationship to the SC.

Adolescent↗
PubMed1981

Left atrial function in acute mitral regurgitation. Factors which modify the regurgitant volume.

Dynamic geometry of the left atrium was studied in open-chest dogs instrumented with ultrasonic dimension gauges for the measurement of the transverse diameter together with left ventricular dimensions and left atrial and ventricular pressures. Three definite phasic changes of the left atrial diameter were observed during the cardiac cycle at the control state; shortening of left atrial diameter with atrial contraction, continuous chamber expansion during ventricular ejection, and either a reduction in the diameter or a plateau during mitral valve opening to onset of the next atrial contraction. Acute onset of mitral regurgitation initially induces a remarkable augmentation of atrial shortening with chamber dilation as a result of an optimal use of the Frank-Starling mechanism of the atrial muscle. When mitral regurgitation is progressively increased, the extent of the atrial shortening and expansion is diminished despite the geometrical advantage of a further increase in atrial diameter, indicating that this extreme dilation no longer provokes the Frank-Starling response and the atrial myocardium is made to operate on a descending limb of function. The amount of regurgitation is highly dependent on the geometry of the mitral orifice and a decrease in regurgitation with vasodilator therapy or with positive inotropic agents may be largely related to a decrease in the size of the left heart cavity, which brings closer together components of the mitral apparatus and increases its competence.

Animals↗
PubMed1983

Effect of the ouabain-quinidine interaction on left ventricular and left atrial function in conscious dogs.

The effect of the ouabain-quinidine interaction was examined in 10 conscious dogs. Left ventricular (LV) pressure, LV dP/dt, LV diameter and left atrial (LA) diameter were measured with high-fidelity micromanometers and sonomicrometer crystals. Ouabain, 0.025 mg/kg, significantly (p less than 0.05) increased LV dP/dt, LV and LA fractional shortening and LV and LA velocity of circumferential fiber shortening (Vcf). In a separate experiment, quinidine was administered as a bolus dose, 3.85 mg/kg, followed by an infusion, 0.28 mg/kg/min. This resulted in steady-state quinidine concentrations that produced no change in wall motion or hemodynamics. When ouabain was given 1 hour into the quinidine infusion, only LV dP/dt increased significantly (p less than 0.05). Ouabain alone increased LV dP/dt 26.4 +/- 3.5%, whereas ouabain during the quinidine infusion increased it by 9.5 +/- 2.3%. Similar differences were seen in the responses to ouabain in the absence and presence of quinidine: LV Vcf, 22.4 +/- 4.9% vs 6.0 +/- 2.1%, LV fractional shortening, 23.1 +/- 4.6% vs 5.8 +/- 2.1%, LA Vcf, 22.7 +/- 5.9 vs 4.6 +/- 2.0% and LA fractional shortening, 21.8 +/- 7% vs 7.8 +/- 3.3%. Thus, in the presence of quinidine the increase in intropy usually seen with ouabain was markedly attenuated. These data suggest that the quinidine-induced increase in digoxin serum concentrations is accompanied by a decrease in the contractile response of the heart to digoxin.

Animals↗
PubMed1995

[Stroke in pacemaker users for sinus node disease. Relevance of atrial function and clinical characteristics].

Several studies reported that the annual incidence of stroke in patients with sick sinus syndrome ranges from 6 to 10% while the incidence of stroke in patients with atrial fibrillation is about 2-4% and about 0.1% in the normal population. We evaluated the prevalence of cerebral ischemia and peripheral embolism and investigated the predictor factors in a population of 80 patients paced for sick sinus syndrome. The implanted pacemakers were 40 ventricular and 40 physiological stimulation mode was based on the physicians judgement. All patients had cerebral computed tomography scan at the time of implant and after 24 months. Statistical analysis included log-rank test and actuarial curve calculated with Mantel-Haenszel method. At the end of follow-up the end-point occurred in 15 patients: 2 patients had asymptomatic cerebral infarction, 2 had fatal stroke, 2 developed peripheral embolysm, 1 to the lower limb and 1 abdominal; in 4 patients a transient ischemic attack occurred, in 2 a minor stroke and in 3 a non invalidant stroke. No statistically significant difference was found among the subgroups; with different pacing modality. In conclusion, multivariate analysis underlines the role of age > 65 years, history of cerebral ischemia, low atrial ejection force and spontaneous echo contrast in the development of embolic episodes.

Aged↗
PubMed1981

Experimental evaluation of atrial function in right atrium--pulmonary artery conduit operation for tricuspid atresia.

Right ventricular bypass operations were performed in dogs by right atrium--pulmonary artery (RA-PA) conduits with closure of the tricuspid valve. Atrial fibrillation (AF) was induced in prebypass (control) and postbypass (postconduit) studies. Six dogs tolerated the procedure and had postoperative sinus rhythm (SR). In the postconduit studies, AF resulted in significant decline in both mean arterial pressure (73 +/- 2 to 65 +/- 2 mm Hg [mean +/- SEM], p less than 0.05) and pulmonary blood flow (1,050 +/- 160 to 880 +/- 110 ml/min, p less than 0.05). However, there were no significant differences between the magnitude of these changes and those during control studies. Mean right atrial pressure was markedly elevated (17.3 +/- 1.3 mm Hg) during SR after the conduit operations, but it did not increase significantly with AF. In volume load studies, pulmonary blood flow increased in proportion to rises between 15 and 30 mm Hg in mean right atrial pressure. The results suggest that right atrial contraction is not critical to the maintenance of pulmonary blood flow following RA-PA conduit operations.

Animals↗
PubMed1988

Bovine adrenal medullary cells contain functional atrial natriuretic peptide receptors.

The recent report that bovine adrenal chromaffin cells synthesized and secreted atrial natriuretic peptide, ANP, suggested that the peptide may have binding sites in the gland itself. Studies in bovine adrenal medulla membranes did reveal a single class of high affinity [125I]-ANP binding sites with a KD of 94 pM and a density of 1.7 pmol/mg protein. Binding was very rapid (association half-time: 2.5 min), and specific in that only unlabelled ANP displaced bound [125I]-ANP. Application of ANP to bovine chromaffin cells in culture, resulted in a concentration-dependent increase in cGMP synthesis. The data suggest the presence of biologically functional ANP receptors in adrenal chromaffin cells.

Adrenal Cortex↗
PubMed1984

Echocardiographic evaluation of atrial function after Senning and Mustard correction for transposition of the great arteries.

Two groups of six children who had undergone either Senning or Mustard repair for uncomplicated transposition of the great arteries were studied with M mode echocardiography derived from a phased array sector scanner picture. The newly created atria were visualised from the subxiphoid region and the upper systemic venous inflow was selected for a simultaneous M mode registration with a subsequent wall motion analysis with a commercially available computer. In the Mustard group of patients the atrial walls seemed to move passively with the overall heart movements, while abrupt atrial wall excursions of both atria synchronous with heart action were noted in all patients after Senning repair. In this group also slow cyclic changes followed respiration. The atrial wall movements were significantly superior (p = 0.001) in the Senning group of patients. It is concluded that, in contrast to the Mustard method, the Senning operation seems to lead to a viable atrium with the capability of increasing and diminishing atrial diameter and with subsequent potential for growth.

Adolescent↗