Echocardiographic analysis of interatrial septal motion.

Interatrial septal motion was analyzed in 12 normal subjects and 19 patients with right or left atrial overloading using a new method for recording echograms of the mid portion of the interatrial septum through each cardiac cycle. In normal subjects, septal motion was characterized by eight distinct points that were identified and designated on the septal echogram. The septum showed gradual anterior motion (toward the right atrium) in mid and end systole and in early diastole. After reaching the most anterior point, it moved posteriorly (toward the left atrium). During mid diastole it showed very little motion. After the P wave of electrocardiogram it showed slight posterior and then anterior motion.In all eight patients with mitral stenosis, the motion of the interatrial septum was diminished. In all seven patients with mitral regurgitation due to chordal rupture, the septal motion was increased. Systolic fluttering of the septum was observed in four of seven patients. In two patients with Ebstein's anomaly, paradoxical motion of the interatrial septum (posterior motion in systole) was observed. In two patients with primary pulmonary hypertension, septal motion was very much decreased. Interatrial septal motion was thought to result from the interatrial pressure gradient through each cardiac cycle. This method of recording the motion of the interatrial septum seems to be useful for diagnosing right or left atrial overloading and for studying hemodynamic events in both atria.     

The valve of the foramen ovale in interatrial right-to-left shunt: Echocardiographic cineangiocardiographic and hemodynamic observations

In postpartum persistent right-to-left shunt at the atrial level, the valve of the foramen ovale fails to close. As a thin valve-flap the septum primum is pushed to the left during the phases of right atrial pressure predominance and closes to the septum secundum, when left atrial pressure exceeds right atrial pressure. Thus, it performs a marked movement during the cardiac cycle, reflecting the interatrial pressure-flow dynamics. With use of M-mode echocardiography, this movement pattern was studied in 24 patients: 13 with cyanotic heart disease (age 2 days to 21 years) and 11 newborns with persistent transatrial right-to-left shunt due to noncardiac disease. Cardiac defects were confirmed by cardiac catheterization and cineangiocardiography. Interatrial right-to-left shunts were proved by M-mode and 2-dimensional contrast echocardiography. The comparison of the M-mode echocardiographic findings in our patient groups with normal atrial septal movement studied in 20 healthy infants and children revealed considerable differences. The characteristic movement of the valve of the foramen ovale also was compared with results obtained by cineangiography and 2-dimensional echocardiography. Analysis of interatrial blood pressure difference provided a pathophysiologic explanation of the septum primum movement in transatrial right-to-left shunt.     

Inversion of the normal interatrial septum convexity in acute myocardial infarction: incidence, clinical relevance and prognostic significance

Inversion of the normal interatrial septum convexity has been described in patients with right atrial pressure or volume overload, but there is no reference to this abnormality in acute myocardial infarction. A group of 576 consecutive patients with acute infarction and serial echocardiographic studies were prospectively evaluated during a mean follow-up period of 406 days. Inverted interatrial septum convexity was found in 30 patients (5.2%); 29 of the 30 presented with inferior infarction with right ventricular involvement (29 [24.4%] of 119) and the remaining presented with cardiac tamponade secondary to heart rupture. The incidence of inverted interatrial septum convexity rapidly decreased, and after 3 months it was present in only five patients. All patients with inverted interatrial septum convexity had a right atrial pressure greater than or equal to pulmonary capillary pressure, a relation found in only 2 of 43 patients with right ventricular involvement and normal septal convexity. In patients with right ventricular infarction, right atrial pressure was higher in the presence of inverted septal convexity (15.9 +/- 4.1 versus 10.5 +/- 4.1 mm Hg, p less than 0.0001) and the incidence of hypotension (10 [34.4%] of 29 versus 15 [17.4%] of 90, p = 0.04) and third degree atrioventricular block (10 [34.4%] of 29 versus 11 [12.2%] of 90, p = 0.006) as well as the mortality rate after 3 months (9 [31%] of 29 versus 11 [12.2%] of 90, p = 0.04) were higher in the presence of inverted convexity than in patients with normal septal convexity.(ABSTRACT TRUNCATED AT 250 WORDS)     

Attenuation of interatrial conduction using right atrial septal catheter ablation

OBJECTIVES: We sought to characterize a method of attenuating interatrial conduction using radiofrequency ablated lesions applied to the right atrial septum. BACKGROUND: Interatrial conduction occurs in specific zones. Recent data suggest that interatrial conduction can be important in triggering and sustaining atrial fibrillation. Therefore, a method for attenuating interatrial conduction may have therapeutic value. METHODS: In 13 healthy pigs, interatrial conduction was evaluated before and after sequential ablation of the right atrial septum, targeting interatrial conduction zones. In six animals, zone 1 (crista terminalis and limbus) was ablated first, followed by ablation of zone 2 (fossa ovalis and coronary sinus ostium). In the other seven animals, the order of ablation was reversed. Electrophysiologic and pathologic findings were correlated. RESULTS: After ablation of zone 1, interatrial conduction was slowed, but there was no block. After ablation of zone 2, conduction was unchanged. After ablation of both zones, complete block was observed in four animals, and there was left atrial quiescence. In the remaining nine animals, incomplete block was observed, with marked conduction slowing or block during sinus rhythm and pacing. Ablation did not adversely affect atrioventricular node conduction, nor did it facilitate sustenance of an atrial arrhythmia. Pathologic analysis revealed that complete interatrial conduction block was associated with confluent ablation of both targeted zones. CONCLUSIONS: Catheter ablation of the right atrial septum attenuated interatrial conduction without disturbing atrioventricular conduction.     

Transesophageal echocardiographic demonstration of distinct mechanisms for right to left shunting across a patent foramen ovale in the absence of pulmonary hypertension

The optimal visualization of the atrial septum and fossa ovalis by transesophageal echocardiography was utilized to demonstrate saline contrast transit across the atrial septum and to relate it to the motion of the flap valve (septum primum) of the fossa ovalis. In three cases, three distinct mechanisms of right to left interatrial shunting in the absence of right ventricular systolic hypertension were identified: 1) transient spontaneous reversal of the left to right atrial pressure differential with each cardiac cycle; 2) sustained elevation of right atrial pressure above left atrial pressure induced by respiratory maneuvers; and 3) aberrant flow redirection across the foramen ovale due to a large right atrial mass. Any of these three mechanisms may be operative during paradoxic embolism in the absence of elevation of right ventricular pressures.     

Frequency and direction of interatrial shunting in valvular pulmonic stenosis with intact ventricular septum and without left ventricular inflow or outflow obstruction: An analysis of 127 patients treated by valvulotomy

This report summarizes observations in 127 patients who underwent pulmonic valvulotomy for valvular pulmonic stenosis with intact ventricular septum and without obstruction to left ventricular inflow or outflow. Of the 127 patients, 30 (24%) preoperatively by dye dilution curves had shunting at the atrial level: in 19 (63%), the shunt was right-to-left, and in the other 11 (27%), entirely left-to-right. The patients with right-to-left interatrial shunts had severe pulmonic valve stenosis (average peak systolic pressure gradient = 120 ± 11 mm. Hg) and small (average diameter 1.1 ± 0.1 cm.) sized defects in the atrial septum (patent foramen ovale). In contrast, the patients with left-to-right shunts had mild to moderate pulmonic valve stenosis (average peak systolic pressure gradient = 60 ± 5 mm. Hg) and relatively large (average diameter = 2.8 ± 0.1 cm.) defects in the atrial septum (true atrial septal defect). The patients with right-to-left interatrial shunts had no significant differences in right versus left atrial pressures. The patients with left-to-right interatrial shunts, however, had left atrial pressures significantly greater than right atrial pressures (7 ± 0.5 vs 5 ± 0.5, p < 0.05). No significant differences were found in ventricular end-diastolic pressures.     

Atrial septal aneurysm--a potential cause of systemic embolism. An echocardiographic study

Atrial septal aneurysm is an uncommon condition. Between 1981 and 1984 10 cases of atrial septal aneurysm were diagnosed by real time cross sectional echocardiography performed in 4840 patients. The aneurysm was associated either with mitral valve prolapse (three patients) or with atrial septal defect (three patients) or occurred in isolation (four patients, two of whom had had a previous embolic event leading to the diagnosis of atrial septal aneurysm by cross sectional echocardiography). During cross sectional echocardiography the aneurysm appeared as a localised bulging of the interatrial septum, which was best seen in the subcostal four chamber view and in the parasternal short axis view at the level of the aortic root. The aneurysm either protruded into only the right atrium (five patients) or moved backwards and forwards between the right and the left atria during the cardiac cycle (five patients). This motion pattern might be related to changes in the interatrial pressure gradient. The two patients who had had a systemic embolism were given anticoagulant treatment, but none underwent surgery. It is concluded that the true prevalence of atrial septal aneurysm might have been underestimated before the routine use of cross sectional echocardiography, that cross sectional echocardiography enables definitive diagnosis of this condition by a non-invasive technique, and that an atrial septal aneurysm should be suspected and looked for by cross sectional echocardiography after an unexplained systemic embolism.     

Giant interatrial septal aneurysm mimicking a right atrial tumor

We report the case of a patient with a giant interatrial septum aneurysm who was admitted to our hospital for analysis of palpitations. Transthoracic echocardiography was not contributive and cardiac magnetic resonance imaging demonstrated a small interatrial septal aneurysm. In our study, only transesophageal echocardiography provided the correct diagnosis, showing a giant interatrial septal aneurysm protruding far away into the right atrium and mimicking a right atrial cystic tumor.     

Rare postsurgical complication of atrial septal defect closure: right inflow obstruction due to inadvertent suturing of eustachian valve to interatrial septum

We report the case of a 20-year-old woman who received corrective surgery for a secundum atrial septal defect, during which right atrial inflow obstruction developed because of inadvertent suturing of the eustachian valve to the interatrial septum. Although reliable cardiac surgical techniques are available, this rather rare complication may have deleterious results for patients. If a previously absent murmur is detected in the lower left parasternal border after atrial septal defect surgery, right atrial inflow obstruction caused by the eustachian valve should be kept in mind and further careful examination undertaken.     

Patency of the interatrial septum in children undergoing cardiac catheterization

Catheter passage into the left atrium from the right atrium greatly facilitates invasive cardiovascular evaluation and reduces the risks attendant on cardiac catheterization studies. We reviewed 371 consecutive cardiac catheterizations to establish the presence of natural interatrial communications. Catheter course, pressure equalization, and left-to-right atrial shunt on recirculation angiography were considered to determine intact interatrial septum (IIS), patent foramen ovale (PFO) or atrial septal defect (ASD). During the first year of life, 88% of infants had PFO or ASD; in 12%, the interatrial septum was intact. In children 1–10 years old, 49% had IIS, 27% had PFO, and 24% had ASD. In children 10–21 years old, 24% had PFO, or ASD. Though there seems to be a greater likelihood of ISS in those with left heart obstruction, hemodynamic factors did not completely explain the timing of closure of the foramen ovale. Presence of an interatrial communication allows catheter entrance into all left heart structures including the aorta; therefore, in patients with PFO or ASD, retrograde arterial procedure or transseptal puncture technique can be avoided when performing left heart catheterization. This appears possible in 88% of those under 1 year of age, in 51% of those 1–10 years old, and in 24% of children 10–21 years old.     

Subxiphoid two-dimensional imaging of the interatrial septum in infants and neonates with congenital heart disease.

The interatrial septum (IAS) was studied by subxiphoid two-dimensional echocardiography (S2DE) in 88 infants under 12 months of age who weighed 1.2-9.1 kg. The IAS was adequately displayed in 87 of 88 patients. The morphology, presence and localization of defects in the IAS were evaluated by S2DE and retrospectively related to the findings at cardiac catheterization. In seven patients with no interatrial communication at cardiac catheterization, the IAS was straight, with an area of central thinning corresponding to the veil-like cover of the septum primum over the foramen ovale. The morphology of the IAS with a stretched, patent foramen ovale (56 patients) indicated the coexistence of a right or left ventricular volume or pressure overload, and was readily distinguishable from the IAS with a secundum type communication (13 patients). In patients with a stretched, patent foramen ovale and left ventricular overload lesions, the IAS was a nearly homogenous, curvilinear structure bowing into the right atrium, with a small area of septal dropout at the superior rim of the septum primum. In the presence of right ventricular overload lesions, the central defect of the foramen ovale was associated with a redundant flap valve of the septum primum billowing into the left atrium. In secundum type communications, the centrally located defect represented a deficiency rather than a redundancy of the septum primum. Balloon atrial septostomy (BAS) in 17 patients produced a secundum-type defect bordered by the flail remnants of the torn septum primum. Blalock-Hanlon septectomy (two patients) resulted in a large, posterior, sinus venosus-type communication which incorporated the preexisting BAS. Ostium primum defects (seven patients) were distinguished from the secundum lesions by their eccentric position in the IAS adjacent to the atrioventricular ring.     

Echography in aneurysm of the interatrial septum

Atrial septal aneurysm can be detected by subcostal echocardiography as a bulge of the intermediate interatrial septum, ballooning toward the right atrium. We retrospectively revised 5412 echo examinations, consecutively performed in our laboratory, and we found 14 cases of atrial septal aneurysm (0.26%), mean age 36 +/- 15 years, 9 males and 5 females. In 7 patients atrial septal aneurysm was wide, including the whole atrial septum; in 5, only cranial two-thirds of the septum were involved and in 2, it regarded only the intermediate septum. No patients referred to arrhythmias, syncope, embolism, endocarditis or transient ischemic neurologic disorders. Cardiac abnormalities or defects were associated to atrial septal aneurysm in 12/14 patients: they consisted of atrial septal defect, mitral valve prolapse, false ventricular tendons or persistent Chiari network. Atrial left-to-right shunt was detected in all 6 cases with atrial communication. Considering each single associated cardiac abnormality, the prevalence of atrial septal aneurysm was 7% in patients with atrial septal defect, 1.7% in those with mitral valve prolapse, 6.6% in persistent Chiari network and 0.9% in false ventricular tendons. In conclusion, echocardiography is the first-choice technique to detect atrial septal aneurysm and other related cardiac defects.     

Atrial septal aneurysm--a potential cause of systemic embolism. An echocardiographic study.

Atrial septal aneurysm is an uncommon condition. Between 1981 and 1984 10 cases of atrial septal aneurysm were diagnosed by real time cross sectional echocardiography performed in 4840 patients. The aneurysm was associated either with mitral valve prolapse (three patients) or with atrial septal defect (three patients) or occurred in isolation (four patients, two of whom had had a previous embolic event leading to the diagnosis of atrial septal aneurysm by cross sectional echocardiography). During cross sectional echocardiography the aneurysm appeared as a localised bulging of the interatrial septum, which was best seen in the subcostal four chamber view and in the parasternal short axis view at the level of the aortic root. The aneurysm either protruded into only the right atrium (five patients) or moved backwards and forwards between the right and the left atria during the cardiac cycle (five patients). This motion pattern might be related to changes in the interatrial pressure gradient. The two patients who had had a systemic embolism were given anticoagulant treatment, but none underwent surgery. It is concluded that the true prevalence of atrial septal aneurysm might have been underestimated before the routine use of cross sectional echocardiography, that cross sectional echocardiography enables definitive diagnosis of this condition by a non-invasive technique, and that an atrial septal aneurysm should be suspected and looked for by cross sectional echocardiography after an unexplained systemic embolism.     

Atrial septal aneurysm with right-to-left interatrial shunting

Interatrial shunting in the presence of an atrial septal aneurysm is an uncommon but well recognized abnormality. Previous case reports have demonstrated that elevated right atrial pressure secondary to pulmonary embolism or right ventricular infarction may cause right-to-left interatrial shunting in the presence of an atrial septal aneurysm. We describe a unique situation in which an atrial septal aneurysm was associated with a right-to-left shunt secondary to severe systemic hypotension and normal right atrial pressure. In this patient, we used midodrine, an oral alpha-1 agonist, to increase systemic arterial pressure, decrease the severity of the shunt, and treat the severe hypoxemia. This case establishes that right-to-left interatrial shunting can result from a decrease in left ventricular afterload with normal right atrial pressure. Oral alpha-1 agonist therapy can be used successfully to treat patients such as ours and possibly others with similar functional abnormalities.     

A simple technique for detecting small defects of the atrial septum

A sensitive technique for detecting small defects of the atrial septum is described. A Valsalva maneuver is used to cause right atrial pressure to exceed left atrial pressure. This reversal of the normal interatrial pressure gradient causes a transient right to left shunt across the defect. The right to left shunt is detected by noting an early appearance deflection in standard indicator-dilution curves performed by injecting indocyanine green dye into the inferior vena cava during the Valsalva maneuver. By means of this technique, 7 of 8 surgically induced defects, from 1 to 12 mm in diameter, were detected. There were no false positive results among 9 control animals with an intact atrial septum. This technique presents a sensitive and simple method for detecting small atrial septal defects. The only equipment required is that used to perform standard indicator-dilution curves.     

Identification of atrial septal defects by cross-sectional contrast echocardiography.

Cross-sectional echocardiography, combined with injections of contrast into peripheral arm veins, has been used to study 15 patients with atrial septal defects and 10 patients with an intact interatrial septum. Of 11 patients with ostium secundum or sinus venosus atrial septal defects and left-to-right shunts a defect could be visualised in all, and in eight some degree of transfer of contrast from right atrium to left atrium was seen. In three of four patients with a dominant right-to-left shunt a defect was seen and in all there was free transfer of contrast from right atrium to left atrium. Though there may be variable loss of echoes in the septal image in patients with an intact interatrial septum, in general no fixed defect is seen an there is no transfer of contrast from right atrium to left atrium. This is a potentially valuable technique in the assessment of patients in whom an atrial septal defect is suspected.     

Single and two dimensional echocardiographic features of the interatrial septum in normal subjects and patients with an atrial septal defect.

The interatrial septum is one of the least studied structures in M mode echocardiography. Two dimensional echocardiography has made it possible to record simultaneous M mode and two dimensional echocardiograms. Such studies were performed in 10 normal subjects and in 9 patients with a secundum atrial septal defect. In the short axis view of the base of the heart, the interatrial septum was visualized in the two dimensional studies as a linear echo running from the posterior aortic wall to the posterior atrial wall and in the M mode records as a series of dense echoes posterior to the aorta. The great variability in echo dropout of the interatrial septum made it impossible to distinguish the normal subjects from the patients with atrial septal defect. The dense echoes of the interial septum in the M mode records gave the false impression that they were filling the left atrium. These data indicate that (1) a secundum atrial septal defect cannot be reliably differentiated from a normal septum using these echocardiographic methods, and (2) the medial location of the interatrial septum should be appreciated so that it will not be confused with a left atrial mass.     

Atrial septal pacing to resynchronize atrial contraction and improve atrial transport function

OBJECTIVES: Atrial septal pacing via a trans-septal breakthrough site within the right atrial septum can shorten global atrial activation time, resulting in significant reduction of recurrence of atrial fibrillation events. This study examined whether this pacing method will lead to resynchronization of atrial contraction and its benefit on hemodynamic function can be maintained for 24 months. METHODS: Thirty patients with atrial fibrillation and delayed atrial conduction were enrolled (17 males, 13 females, mean age 73 +/- 7 years). Trans-septal breakthrough site within the right atrial septum was identified through pacing from the dorsal left atrium. Continuous atrial septal pacing at the trans-septal breakthrough site was performed for 24 months. Time difference (TD) between right and left atrial contractions was measured during atrial septal pacing and sinus rhythm by pulse Doppler echocardiography of the trans-tricuspid (P-At) and mitral (P-Am) blood flows (TD = P-Am - P-At). RESULTS: The atrial lead was screwed near the fossa ovalis in 29 of 30 patients. Atrial septal pacing yielded significantly shorter P wave duration (101.9 +/- 10.4 vs 139.6 +/- 14.7 msec, p < 0.001), leading to significant reduction of TD in atrial contraction (-8.8 +/- 10.0 vs 29.8 +/- 13.6 msec, p < 0.001)as compared to sinus rhythm. Both shorter P wave duration and reduced TD during atrial septal pacing remained statistically significant during the follow-up period as compared to sinus rhythm. Both left atrial diameter and A to E ratio of filling waves at mitral valve were significantly decreased at 12 months and remained decreased at 24 months. CONCLUSIONS: Atrial septal pacing at the trans-septal breakthrough site can resynchronize atrial contraction and results in improved hemodynamic effects during 24 months of follow-up.     

Diagnosis of atrial septal defect using magnetic resonance imaging

We studied the morphological features of defects of the interatrial septum using magnetic resonance imaging (MRI) to determine the sizes of defects and other abnormalities. MR images were obtained in 28 patients with atrial septal defect, including five cases with complicated anomalies (two with Ebstein's anomaly, one pentalogy of Fallot, and one anomalous pulmonary vein connection and azygos continuation). Images were also obtained in the control subjects including seven normal volunteers and 142 patients with various acquired heart diseases. The diagnosis of atrial septal defect was established by cardiac catheterization, angiography and two-dimensional echocardiography prior to the MRI studies, and in 14 patients, the diagnosis was confirmed by surgery. The MRI unit had a superconducting magnet and operated at 0.25 or 0.50 Tesla. A spin echo pulse sequence was used with an echo time of 40 or 60 msec. At the beginning of this study, non-gated MRI images were obtained in the 28 controls and in three patients with atrial septal defect. Nongated MRI could not image the anatomical structure of the interatrial septa of 12 of the 28 controls, or any of the three patients with atrial septal defect. Nongated MRI was, therefore, inadequate for visualizing cardiac anatomy. Gated MRI images were obtained in 141 controls and in 25 patients with atrial septal defect. Gated MRI revealed the interatrial septum, interventricular septum, atrioventricular septum, mitral valve, tricuspid valve and other intracardiac structures in most subjects. In 17 control subjects (12%), however, there was a very faint signal from the central portion of the interatrial septum. In these instances, there was a gradual fading of the signal of the interatrial septum, so that they could be distinguished from the atrial septal defect. The sudden disappearance of the signal from the interatrial septum was observed by gated MRI in all 25 patients with atrial septal defect. The sizes of the defects by MRI coincided with the findings at surgery in all 14 patients. MRI showed right atrial dilatation, right ventricular hypertrophy and dilatation, and pulmonary artery dilatation in most of the patients having atrial septal defect. Complex anomalies associated with atrial septal defect were also clearly shown by MRI, such as displacement of the tricuspid leaflets in two patients with Ebstein's anomaly, and anomalous pulmonary venous connection and persistent left superior vena cava in one patient. These results indicated that gated MRI is a valuable noninvasive method of diagnosing atrial septal defect and complicating anomalies.     

Atrial septal aneurysm: a report of three cases

Three cases of isolated atrial septal aneurysm are reported. Case 1: A 66-year-old man visited our hospital for detailed examination and evaluation of premature ventricular contractions and left ventricular hypertrophy previously detected. Echocardiography revealed an atrial septal aneurysm protruding into the left atrium in the early systolic phase and into the right atrium during the mid-systolic to diastolic phase. Subxiphoid M-mode echocardiography showed triphasic movement of the wall of the atrial septal aneurysm toward the left atrium during the end-diastolic to systolic phase, which was enhanced during inspiration. No abnormalities were found by Doppler echocardiography. Cardiac catheterization revealed normal intracardiac pressures and oxygen saturations, but a right arteriogram revealed a defect in the right atrium. Case 2: A five-month-old male infant was referred to our hospital for detailed examination and evaluation of a heart murmur. Echocardiography revealed an atrial septal aneurysm in which a part of the interatrial septum protruded into the right atrium. Case 3: A one-day-old female infant was admitted to our hospital for detailed cardiac examination. Echocardiography revealed that the entire interatrial septum protruded into the right atrium. In Cases 2 and 3 the morphology of the aneurysms did not show cyclic or respiratory change. These two cases had no other abnormalities on echocardiography or Doppler echocardiography. The mechanism of the wall movement in Case 1 seemed to be attributed to differences in pressures between the right and left atria and in properties of the aneurysmal walls. Enhancement of the protrusion of the aneurysmal wall toward the left atrium during inspiration was considered due to inspiratory increase of right atrial pressure.