Echocardiographic analysis of interatrial septal motion.
Explore the source record for details and available documents.
Atrial Function↗
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.
Prostaglandins and cyclic nucleotides in cardiac function.
Explore the source record for details and available documents.
Animals↗
Pure anterior conduction delay: a variant "fascicular" defect.
Based upon electrocardiographic studies of conduction disturbances, the human intraventricular conduction system has been considered trifascicular: a right bundle and a bidivisional left bundle. Right bundle branch block, left anterior hemiblock, and left posterior hemiblock have been described. Microscopic and endocardial mapping studies, however, do not demonstrate a corresponding anatomical basis of this useful functional concept. Atrial premature beats in our two cases resulted in ventricular aberrancy which strongly suggests an additional form of a functional conduction delay. Such delay is manifest as a narrow QRS with anterior displacement in the horizontal plane but no axis shift in the frontal plane. This aberrancy is important to recognize because it can mimic the ECG findings of true posterior myocardial infraction. We do not postulate, however, a specific fascicle of the left bundle as the anatomic substrate for this recently recognized effect.
Adult↗
Echocardiography for the evaluation of the tricuspid valve, right ventricle, and atrium.
Explore the source record for details and available documents.
Atrial Function↗
Ultrastructural alterations of atrial myocardium induced by adriamycin in chronically treated animals.
The clinical use of adriamycin (AM) is limited by a possible dose-dependent myocardiopathy. Severe lesions of ventricular myocardium widely described by electron microscopy have been correlated to irreversible congestive heart failure. On the other hand, the atrial contractile elements which differ from the ventricular ones because of the presence of the so-called specific granules have rarely been considered. In the work described in this paper, adriamycin was injected into rabbits and mice according to schedules of chronic toxicity. At the end of the treatment the atrial myocells presented diffuse ultrastructural lesions of mitochondria, sarcoplasmic reticulum and myofibrillar bundles. These alterations might be caused by the ribonucleoprotein synthesis inhibition, by a direct drug toxicity or by an energetic crisis due to early mitochondrial lesions. Besides, adriamycin produces a decrease of the specific atrial granules that play a hypothetic role in the metabolism of myocardial cells. However, lack of information about the contents and the exact function of atrial granules does not allow us to conclude that their decrease in treated animals has a pathogenetic significance in myocardiopathy induced by adriamycin.
Animals↗
Blood flow in pulmonary veins: I. Studies in dog and man.
The pattern of blood flow in the large extra parenchymal pulmonary veins is pulsatile in both dog and man. This pulsatility is dominated by the changes in left atrial pressure taking place throughout the cardiac cycle. No pulsatile component of low in the large pulmonary veins could be attributed to forward transmission of a flow pulse conducted from the lung capillaries. The findings suggest that there must be a region of considerable compliance in the pulmonary venous system which can absorb pulsations from the lung capillaries and eliminate their transmission to the left atrium.
Animals↗
Detector electrode introduced by mediastinoscopy for atrial triggered cardiac pacing. A follow-up of electrode function in 82 patients.
An atrial detector electrode was introduced by mediastinoscopy in 82 patients requiring permanent cardiac pacing. There were no complications. An adequate P wave was recorded in 80 patients. During the following week, the P wave became ineffective in 5 patients; angina occurred in 2 and atrial arrhythmias in 2. Atrially triggered ventricular pacing established in 73 patients and was followed in 71 patients for a period of 1 to 113 months. In 17 cases, it had to be terminated because of an ineffective or unstable P wave,in 6 cases because of atrial arrhythmias, and in 4 cases because of advanced age and recurrent infections. The method is technically simple and place little stress on the patient.
Adult↗
Atrial receptors in the cat.
Action potentials were recorded from slips of the cervical vagi in anaesthetized cats. Single functional units with atrial patterns of discharge (type A, B and Intermediate) were first obtained and then attempts were made to alter (i.e. convert) their patterns of discharge. Finally the points of origin of their action potentials were located. The investigations were done in five stages. 2. In the first series, thirty unselected units were investigated in thirty cats. Twenty-five of these were located in the endocardium of vein-atrial system and consisted of two type A, fifteen type B and eight Intermediate type units. The remaining five units were located elsewhere in the chest Conversion of the pattern of discharge was achieved in sixteen of the twenty-five atrial units. Both atrial type A units were converted. 3. In the second series, eight type A units were selectively studied in twelve cats. Five were located in the atrial endocardium and all were converted. Of the other three units which were located at other sites in the chest, one could not be converted. 4. In the third series, four type A units which could not be converted were selectively studied in twenty cats. All were located outside the atria. 5. In the fourth series, three type B units which could not be converted were selectively studied in six cats. These units were located in the pulmonary veins and in the lateral walls of the atria. 6. In the fifth series, fifty-five units were investigated in three anaesthetized spontaneously breathing cats. The proportion of the types of units were similar to that obtained in the artificially respired cats (first series). 7. The present study has shown that atrial receptors with a type A pattern of discharge are relatively rare in the cat and that conversion of the patterns of discharge is a common phenomenon. Evidence is presented which suggests that there is one basic type of atrial receptor whose pattern of discharge is determined by their precise location in the vein-atrial system.
Action Potentials↗
Hemodynamic evaluation of Fontan operation in tricuspid atresia.
Six patients underwent hemodynamic studies at 2 to 34 months (mean 15 months) following a modified Fontan operation. Only one patient had a valve at the inferior vena cava (IVC)-right atrium (RA) junction. Average age at surgery was 12 years (range 5-26 years). Three patients were catheterized twice. Postoperative studies showed four patients to be in sinus rhythm and two in junctional rhythm. Two patients had a RA-left pulmonary artery (LPA) gradient across the conduit of 1.5-10 mm Hg. The RA pressure was elevated an average of 17 mm Hg (10-34). All patients showed good atrial transport function regardless of their rhythm. The average arterial saturation was 92% (87%-97%), which was an improvement of 13% over preoperative values. Residual hypoxemia was due to pulmonary vein desaturation and to atrial right-to-left shunting early after surgery and to atrial right-to-left shunt alone, later. Death followed re-operation for removal of the porcine valves in the patient with two valves inserted. Macroscopically, both valves were found to have fibrous tissue ingrowth that had fixed them in a semi-open position.
Adult↗
[Studies of left ventricular function during 2-stage auricular stimulation in coronary heart disease].
Explore the source record for details and available documents.
Atrial Function↗
Fine structure of cells and their histologic organization within internodal pathways of the heart: clinical and electrocardiographic implications.
The fine structure of the normal internodal pathways was studied in 1 human and 2 canine hearts and correlated with histologic observations on more than 100 human and 10 canine hearts. From the electron microscopic studies six different kinds of myocardial cells were classified from two locations: the Eustachian ridge (posterior internodal pathway) and the Bachmann bundle (anterior internodal pathway). Five of the six kinds of cells (working myocardial cells, Purkinje-like cells, either broad or slender transitional cells and P cells, all previously described) were present in both locations. A sixth cell, pleomorphic and dark in appearance, with a special intertwined relation to P cells, is newly designated as an ameboid cell. It was found solely in the Eustachian ridge. In the same area a rare direct contact between a nerve and a myocardial cell was observed. The importance of these different kinds of cells, their respective cell connections, and their topographic locations inside the internodal pathways are discussed relative to certain functions such as rapid conduction and subsidiary pacemaking. The possible influence of these factors on clinical electrocardiographic changes is considered.
Animals↗
"Ischemic" heart disease in fire fighters with normal coronary arteries.
Near maximal stress testing conducted on a group (N = 90) of randomly selected Los Angeles City fire fighters (age 40-59 yrs.) revealed that 10% had ischemic ECG changes. These ischemic ECG responses were confirmed during a second test conducted two to four weeks after the initial test. Coronary heart disease (CHD) risk factor analysis revealed that in general the men were not at high risk for CHD. Six of the nine men elected to undergo cardiac catheterization and angiography. One patient had severe triple vessel disease and subsequently underwent aorto-coronary bypass surgery. Another had 50% obstruction in the circumflex branch of the left coronary while the other four men had no visable signs of coronary obstruction. The men with "normal" coronaries, however, did show signs of abnormal cardiac function during atrial pacing. One man had cardiac enlargement, hypokinesis, ischemic ECG and abnormal lactate metabolism. Another had abnormal lactate metabolism and ischemic ECG. A third man had moderate cardiac enlargement with anterior wall hypokinesis. The fourth had ischemic ECG changes with angina but otherwise normal cardiac function. All four of these men had pressures which were within normal limits. These data show that some fire fighters have "ischemic" heart disease with patent coronary arteries. This disease may be due to job related factors (i.e. carbon monoxide and other noxious fumes, catecholamines, etc.) which reduce myocardial oxygen supply or greatly increase myocardial oxygen demands.
California↗
Behavior of cardiac receptors with nonmyelinated vagal afferents during spontaneous respiration in cats.
Activity from left atrial and left ventricular receptors with nonmyelinated vagal afferents (mean conduction velocity, 1.2 m/sec) was recorded in 13 closed-chest spontaneously breathing cats anesthetized with alpha-chloralose. The anatomic position of each receptor was determined by probing the opened heart at the conclusion of the experiment. Three of eight left atrial receptors and four of five left ventricular receptors were silent under resting conditions. The mean discharge frequency under resting conditons for the six receptors displaying spontaneous activity was 1.0 +/- 0.15 impulse/sec. Thus cardiac receptors with vagal nonmyelinated afferent have a low resting discharge in spontaneously breathing cats. The frequency and pattern of discharge of atrial but not of ventricular receptors was altered during spontaneous respiration. The atrial receptors discharged with cardiac rhythmicity during end inspiration and early expiration when transmural pressure was greatest and were silent for the remainder of the respiratory cycle. Whe respiration was augmented by CO2 breathing or blood volume was increased, the rate of discharge was a linear function of atrial transmural pressure. Eleven ventricular receptors with nonmyelinated afferents (mean conduction velocity, 1.0 m/sec) were exposed to graded volume expansion and phenylephrine infusion in eight open-chest and three spontaneously breathing cats. Raising left ventricular end-diastolic pressure alone increased the frequency of discharge, and a concomitant increase in systolic pressure caused a further increase in firing.
Animals↗
Results following physiological repair for tricuspid atresia.
Fourteen patients underwent a physiological operation for tricuspid atresia. Seven patients survived up to 3 years after operation. Six patients underwent hemodynamic studies 2 to 34 months postoperatively (mean, 15 months). Average age at the time of operation was 14 years (range, 5 to 25 years). Postoperative studies showed 4 patients to be in sinus rhythm and 2 in junctional rhythm. Right atrial pressure was elevated an average of 17 mm Hg (range, 10 to 34 mm Hg). All patients showed good atrial transport function regardless of their rhythm. Two had a right atrium-left pulmonary artery gradient of 1.5 to 10 mm Hg across the conduit. Average arterial saturation was 92% (range, 87 to 97%), on improvement of 13% over preoperative values. Residual hypoexmia was due to pulmonary vein desaturation and to atrial right-to-left shunting early postoperatively and later, to atrial right-to-left shunting alone.
Adolescent↗
Atrial receptors in the dog and rabbit.
1. Action potentials were recorded from slips of the cervical vagi in anaesthetized dogs and rabbits. Single functional units with atrial patterns of discharge (Paintal Type A, B and intermediate) were obtained and then attempts were made to alter (i.e. convert) their patterns of discharge. Finally the points of origin of these action potentials were located.2. Thirty unselected units were investigated in thirty dogs. Twenty-seven of these were located in the endocardium of the vein-atrial system and the ratio of the type A, type B and intermediate type receptors was 1:16:10; three units were located elsewhere in the chest. Conversion of the pattern of discharge was achieved in twenty of the twenty-seven units; conversion was achieved in the single type A unit.3. In a second series of experiments in dogs, eight Paintal Type A units were selectively studied in fifteen animals. Four of these were located in the endocardium and all were converted. The remaining four were located outside the endocardium and conversion could not be achieved in two of these. Thus in the entire investigation, the ;type A' units which could not be converted were all located at sites other than the atrial endocardium.4. In the corresponding unselected study in the rabbit, eleven units were studied in eleven animals. Nine of these units were located in the atrial endocardium and the ratio of the type A, type B and intermediate type receptors was 2:1:6. Conversion was achieved in both type A units, the sole type B unit and two of the intermediate units. One of the two units found outside the atrial endocardium was a ;type A' unit and could not be converted.5. The present investigation has shown that the atrial receptors with a Paintal Type A pattern of discharge are relatively rare in both dogs and rabbits. Conversion of the pattern of discharge is a relatively common phenomenon. Evidence for the proposition that there is one basic type of atrial receptor whose pattern of discharge is determined by its precise location in the vein-atrial system is discussed.
Action Potentials↗
Electrophysiologic effects of atropine on human sinus node and atrium.
Electrophysiologic studies were conducted in 17 patients without apparent sinus node disease before and after intravenous administration of 1 to 2 mg of atropine. Mean values in milliseconds (+/- standard error of the mean) before and after administration of atropine were as follows: sinus cycle length 846 +/- 26.4 versus 647 +/- 20.0 (P less than 0.001); sinus nodal recovery time 1,029 +/- 37 versus 774 +/- 36 (P less than 0.001); mean calculated sinoatrial (S-A) conduction time 103 +/- 5.7 versus 58 +/- 3.9 (P less than 0.001); mean P-A interval 34 +/- 1.5 msec versus 31 +/- 1.5 (P less than 0.05); mean atrial effective and functional refractory periods during sinus rhythm 285 +/- 11.3 versus 238 +/- 7.9 and 331 +/0 11.6 versus 280 +/- 8.6, respectively (P less than 0.001 for both); mean atrial effective and functional refractory periods measured at equivalent driven cycle length 239 +/- 7.7 versus 213 +/- 7.4 and 277 +/- 11.4 versus 245 +/- 9.5, respectively (P less than 0.001 for both). In conclusion, atropine shortened sinus cycle length, sinus nodal recovery time and calculated S-A conduction time. The shortening of atrial refractory periods with atropine implies that vagotonia prolongs atrial refractoriness in man.
Adult↗
[On the mechanism of valve plane (author's transl)].
A detailed description of the functional sequence and mechanism of the valve plane movements is given as an extension of the studies on the functional morphology of cardiac movements. The valve plane mechanism is driven in the small, rapidly beating heart by the contraction of the external and internal spiral fibres of the myocardium which decreases the width of the chamber. The atrium is enlarged during systole by the descent of the valvular ring towards the apex. The auricular apendices must act as a compensation reservoir giving the atrial wall the necessary freedom of movement within the pericardial dome. Under these working conditions (hypovolaemia, decreased venous return pathophysiological consequences are discernible as subendocardial bleeding secondary to increased sliding movement of the inner layer of the myocardium against the middle layer. Chamber dilation as a consequence of endocardial fibrosis is explained as a result of progressive rigidity of endo-epicardial fixation. These structural changes progressively impair the systolic-diastolic changes in wall thickness.
Animals↗
An analysis of direct and indirect measurements of left atrial filling pressure.
Left ventricular function may be assessed by direct catheter measurements of left atrial pressure or by indirect measurements of pulmonary artery wedge pressure or pulmonary artery end-diastolic pressure. Controversy exists as to how closely the indirect measurements correlate with true left atrial pressure and to which is the most accurate. To clarify this probelm, we studied 43 patients undergoing cardiac surgical procedures with cardiopulmonary bypass. Both left atrial catheters for direct measurement and Swan-Ganz catheters were placed at the time of surgery. All patients were monitored continuously for 48 hours and hourly measurements were recorded. The resultant 1,620 left atrial pressure and pulmonary artery wedge pressure figures and 1,860 left atrial pressure and pulmonary artery end-diastolic wedge pressure measurements were subjected to computer analysis. The following conclusions have been found: (1) Pulmonary artery wedge pressure is a better indirect measure of left atrial pressure than is pulmonary artery end-diastolic wedge pressure (pooled correlation coefficient 0.629); (2) direct left atrial pressure measurement is more reliable and has fewer complications than indirect measurements; (3) there is no consistent correlation between left atrial pressure and central venous pressure (pooled correlation coefficient 0.3). A discussion of our results and the problems associated with left atrial catheters and Swan-Ganz catheters is presented.
Atrial Function↗