Left Outflow Research Articles

The effect of aortic valve replacement on N-terminal natriuretic propeptides in patients with aortic stenosis.

Increased plasma concentrations of natriuretic peptides have been demonstrated to be associated with increased intracardiac pressure and left ventricular (LV) hypertrophy. After aortic valve replacement (AVR) in aortic stenosis patients, there is a relief of the left outflow obstruction with a substantial hemodynamic improvement. This is followed by a gradual regression of the LV hypertrophy. After AVR, reduction in LV filling pressure is expected to occur rapidly, while regression of LV hypertrophy will take place over a longer time period. On this basis we hypothesized that the plasma levels of N-terminal proatrial natriuretic peptide (NT-proANP) would be reduced early in the postoperative period, while N-terminal probrain natriuretic peptide (NT-proBNP), through its closer reflection of LV hypertrophy, would be sustained for a longer period. Two groups of patients with aortic stenosis undergoing AVR were followed for 4 and 12 months, respectively. Plasma concentrations of NT-proANP and NT-proBNP were measured before and after AVR and related to preoperative findings and changes in the aortic valve area index. Before AVR, the patients had significantly increased plasma levels of NT-proANP and NT-proBNP. After AVR, NT- proANP was decreased at 4 and 12 months but remained elevated compared with controls. N-terminal-proBNP tended to decrease, but did not change significantly. When the patients were followed for 12 months, only those with elevated preoperative pulmonary capillary wedge pressure had decreased peptide levels (NT-proANP: p = 0.017, NT-proBNP: p = 0.058). There was no regression of LV hypertrophy. The patients with the largest postoperative valve area index [1.27 (1.10-1.55) cm2/m2] had the largest reduction of NT-proBNP (47%). Those with the smallest valve area index [0.67 (0.54-0.73) cm2/m2] had no decrease in NT-proBNP. Our study suggests that a reduction in left atrial pressure is the main factor causing the change of NT-proANP level after AVR. A small prosthetic valve orifice area with a high aortic valve gradient might prevent regression of LV hypertrophy, thus representing a stimulus for increased cardiac secretion of NT-proBNP.

Ventricular tachycardias arising from the aortic sinus of valsalva: an under-recognized variant of left outflow tract ventricular tachycardia

OBJECTIVESTo describe a normal heart left bundle branch block, inferior axis ventricular tachycardia (VT), that could not be ablated from the right or left ventricular outflow tracts.BACKGROUNDWhether these VTs are epicardial and can be identified by a specific electrocardiographic pattern is unclear.METHODSTwelve patients with normal heart left bundle branch block, inferior axis VT and previously failed ablation were included in this study. Together with mapping in the right and left ventricular outflow tracts, we obtained percutaneous epicardial mapping in the first five patients and performed aortic sinus of Valsalva mapping in all patients.RESULTSNo adequate pace mapping was observed in the right and left ventricular outflow tracts. Earliest ventricular activation was noted in the epicardium and the aortic cusps. All patients were successfully ablated from the aortic sinuses of Valsalva (95% CI 0% to 18%). The electrocardiographic pattern associated with this VT was left bundle branch block, inferior axis and early precordial transition with Rs or R in V2or V3. Ventricular tachycardia from the left sinus had rS pattern in lead I, and VT from the noncoronary sinus had a notched R wave in lead I. None of the patients had complications and all remained arrhythmia-free at a mean follow-up of 8 ± 2.6 months.CONCLUSIONSNormal heart VT with left bundle branch block, inferior axis and early precordial transition can be ablated in the majority of patients from either the left or the noncoronary aortic sinus of Valsalva.

Grown-up congenital heart disease--medical demands look back, look forward 2000.

A new medical community, the grown-up congenital heart patients--GUCH--has resulted from successes of cardiac surgery over 30-40 years. Many survivors have complicated problems, medical and surgical, demanding experience and expertise neither provided nor organised in most countries. Islands of good care exist with difficulty. The experience of one specialist GUCH unit established for 25 years shows that 55-60% admissions are for complex lesions, particularly after complicated surgery. The patients' overall costs are at least twice those of other cardiac patients. GUCH admissions are about 5-8% of the total, varying according to the population/region served. Supervised medical care for GUCH is equally important in outpatient services, involving 3 times the secretarial time of other cardiac patients, an accessible database and a "helpline" for doctors and patients. This may be life-saving in patients with complex conditions. The GUCH population is ageing, with increasing numbers of complex patients. 30% of admissions now are over 40 years old, and 5% are over 60, confirming that this is an adult medical speciality, not paediatric. Invasive investigations and arrhythmias provide the most frequent reasons for admissions--atrial flutter is the commonest arrhythmia, needing experts when it occurs in Fontan, transposition, etc. Routine coronary arteriography is also important. In cardiac surgery, one in five admissions presents organisational problems. Reoperation, now as many as 9 or 10 times, has to be optimised. Reoperation on left and right outflow tracts-for changing valves and conduits--is more common than first operations. GUCH patients represent a relatively small portion of the whole population. Such patients in a population of 7-8 million need to be concentrated in 1-2 centres, depending on culture, religion, geography, language etc., to provide necessary experience, expertise and education.

Left Atrial Appendage Outflow Velocity Index is Superior to Conventional Criteria for Prediction of Maintenance of Sinus Rhythm after Cardioversion. An Echocardiographic Study in Patients with Atrial Fibrillation of a Few Months' Duration

Objective - To investigate whether left atrial appendage outflow velocity alone or in relation to left atrial diameter is a superior predictor of sinus rhythm maintenance after cardioversion compared with traditional clinical or echocardiography parameters. Design - Sixty-two patients with their first episode of atrial fibrillation were examined using echocardiography before DC-cardioversion. At one month's follow-up, 42 patients had maintained sinus rhythm (group A), and 20 had relapsed into atrial fibrillation (group B). There were no differences in arrhythmia duration or antiarrhythmic therapy between the groups. Results - Left atrial diameter measured by echocardiography was smaller in group A (42 mm, 95% CI 40.9-44.1 mm) compared with group B (46 mm, 95% CI 43.4-48.2, p < 0.05). Patients in group A had a higher left atrial appendage outflow velocity at 0.44 m/s (95% CI 0.39-0.49) compared with 0.34 m/s (95% CI 0.30-0.37) in group B (p < 0.01). The ratio of left atrial appendage flow to left atrial diameter was 0.011 (95% CI 0.009-0.012) in group A compared with 0.008 (95% CI 0.007-0.009) in group B, and 63% (95% CI 33-78) of the patients in group A had velocity ratio >0.009 compared with 20% (95% CI 2-38) in group B, (p < 0.01). Stepwise multiple logistic regression analysis showed that a velocity ratio >0.009 was the only predictor for maintenance of sinus rhythm one month after cardioversion with an odds ratio of 6.4 (95% CI 1.9-23.8), (p = 0.004). Conclusion - The ratio of left atrial appendage outflow velocity to left atrial diameter is superior to the traditionally used criteria for prediction of maintenance of sinus rhythm following DC-conversion of first-episode atrial fibrillation.

Invited commentary

Invited commentary

Transoesophageal echocardiography-guided cardioversion of atrial fibrillation or flutter. Selection of a low-risk group for immediate cardioversion

Despite exclusion of left atrial thrombi by transoesophageal echocardiography, cardioversion-related thromboembolism has been reported in atrial fibrillation or flutter. To define a low-risk group for cardioversion without previous anticoagulation, patients were selected for immediate cardioversion if there were no thrombi, no echo spontaneous contrast and the outflow velocity of the left atrial appendage was greater than 0.25 m. s(-1)on transoesophageal echocardiography. Two hundred and forty-two consecutive patients referred for cardioversion of atrial fibrillation or flutter with a duration of more than 2 days and no anticoagulation therapy were examined with transoesophageal echocardiography. After the transoesophageal echocardiography examination, patients who were eligible for immediate cardioversion were anticoagulated with low molecular weight heparin (dalteparin) subcutaneously, together with warfarin prior to cardioversion. Dalteparin treatment was continued until the patient had reached therapeutic prothrombin values. Based on the transoesophageal echocardiographic findings the patients were divided into two groups: immediate cardioversion, group A, with a mean age of 62+/-13 years (n=162); or conventional warfarin treatment before cardioversion, group B, with a mean age of 67+/-10 years (P<0.05) (n=80). In group A, lone atrial fibrillation or flutter was more common (53%; 95% CI: 45-61) compared to group B (34%; 95% CI: 23-44, P<0.05), while heart disease was more common in group B (45%; 95% CI: 34-56) compared to group A (31%; 95% CI: 24-39, P<0.05). Echocardiography revealed thrombi in 5% (95% CI: 2.6-8) of the patients, left atrial size was larger, fractional shortening lower, and a higher proportion had impaired left ventricular function in group B. No thromboembolic event occurred at or after cardioversion in any of the patients; however, before planned cardioversion one transitory ischaemic attack, one lethal stroke and one cardiac death occurred in three of the patients with thrombi despite warfarin therapy. One-month follow-up maintenance of sinus rhythm was 75% in group A compared to 45% in group B (P<0.01). After using our transoesophageal echocardiographic exclusion criteria (no thrombi, no spontaneous echo contrast and left atrial appendage outflow velocity > or = 25 m. s(-1)) cardioversion can safely be performed in 2/3 of patients with atrial fibrillation or flutter without previous anticoagulation therapy. These patients maintained sinus rhythm significantly better after 1 month compared to patients with prolonged warfarin therapy before cardioversion.

Molecular determinants of left and right outflow tract obstruction.

Congenital heart defects represent the most common group of human birth defects; they occur in 0.8-1% of live births and in 10% of spontaneously aborted fetuses. Heart defects seen in newborns typically represent specific morphogenetic defects of individual chambers or regions of the heart, with the remaining portions of the heart developing relatively normally. These developmental defects are commonly compatible with the intrauterine circulation, where the pulmonary circulation and systemic circulation work in concert, resulting in adequate embryonic growth and development. After delivery, however, significant cardiac symptoms develop. In many of these disorders, cyanosis is the earliest feature, while in others, cardiovascular collapse occurs before diagnosis. In this review, obstruction of the left and right sides of the heart are discussed. In these disorders, ventricular hypoplasia resulting in single ventricle physiologic characteristics is typical. The unaffected ventricle in these cases is usually morphologically and physiologically normal. These conditions include hypoplastic left heart syndrome and aortic coarctation on the left side, pulmonary stenosis, tetralogy of Fallot, and other complex right ventricle obstructive disorders. Many of these disorders occur in association with genetic syndromes identifiable by dysmorphic features. In some cases, the gene(s) has been identified or the genetic pathway has been defined. The purpose of this review is to discuss the molecular determinants of these obstructive disorders.

Prenatal diagnosis of heart defects and associated chromosomal aberrations

According to epidemiological studies on newborns, the association of congenital heart defects with chromosomal anomalies varies between 4 and 12%. Prenatally this rate is probably higher, due to antenatal death occurring in fetuses with chromosomal aberrations. The aim of the study was therefore to determine the rate and the distribution of chromosomal aberrations in prenatally detected heart defects. Within a period of 7 years fetal echocardiography was performed on 2716 fetuses at high risk for CHD. The analysis of the fetal heart was achieved by the visualization of different planes. Once a heart defect was detected, karyotyping was performed after amniocentesis, cordocentesis or chorion villous sampling, or in a few cases postnatally from cord blood. Prenatal ultrasound findings were confirmed postnatally by ultrasound examination or, in case of abortion, stillbirth or neonatal death, by autopsy. A total of 203 fetal heart malformations were detected and 46 of them (22%) had associated chromosomal anomalies. 60% of all cases and 80% of the study group had extracardiac anomalies. Only eight out of the 46 pregnant women (17.5%) were older than 35 years. Eight out of the 15 fetuses with trisomy 18 had a ventricular septal defect, 9/13 fetuses with trisomy 21 had an atrioventricular septal defect and all 5 fetuses with monosomy X had a left heart outflow obstruction. No typical cardiac defects were found in the remaining 13 fetuses (5 trisomy 13, 2 triploidies, 6 miscellaneous). Of the 13 live births (23 terminations of pregnancy and 10 intrauterine deaths) 6 children survived (46% and overall survival rate 13%). The following rates of associations with aneuploidies were found: atrioventricular septal defect 55%, ventricular septal defect and aortic coaction both 43%, tetralogy of Fallot and double outlet right ventricle both 36%. In comparison, fetuses with isomerism, transposition of the great arteries and pulmonary atresia or stenosis had normal chromosomes. We conclude that the rate of association of heart defects and chromosomal abnormalities is higher prenatally than in the neonatal period and is approximately 22%. After detecting a fetal cardiac malformation, karyotyping is mandatory for the further management of pregnancy. The likelihood of detection of an aneuploidy increases when some typical heart defects are detected or when an association with extracardiac anomalies is found.

Pattern of pulmonary venous blood flow in the hypoplastic left heart syndrome in the fetus

OBJECTIVETo determine whether restriction at the atrial septum in the newborn with hypoplastic left heart syndrome can be predicted accurately by examining the pattern of pulmonary venous flow in the...

Prevalence and clinical significance of cardiac murmurs in neonates

AIMTo determine the prevalence and clinical significance of murmurs detected during routine neonatal examination.METHODSIn a two year prospective study, 7204 newborn babies underwent routine examination by senior house officers. All...

Intraoperative transesophageal echocardiography for pediatric patients with congenital heart disease.

Intraoperative transesophageal echocardiography for pediatric patients with congenital heart disease.

Left ventricular support with the implantable AB-180 centrifugal pump in sheep with acute myocardial infarction.

A small, 257 g centrifugal pump was tested as a left ventricular assist device (LVAD) in sheep given a myocardial infarction. Pump performance, hemolysis, end organ function, weaning, explant procedure, and the incidence of thromboemboli at autopsy were studied over intervals of 1 to 44 days. Twelve sheep were given acute myocardial infarction by ligation of the anterior descending coronary artery and 11 had insertion of the AB-180 Circulatory Support System (CSS). One sheep served as a control for the space occupying effects of the pump in the left chest. Inflow was from the left atrium and outflow was to the descending thoracic aorta. Heparin (57-83 U/ml) in sterile water was infused into the pump at a rate of 10 ml/hr. Pump flows of 1-5.7 L/min were tested. The AB-180 CSS supported 73.5% of the total cardiac output (pump + heart) of 3.89 L/min, with a mean arterial pressure of 86 +/- 7 mmHg at a pump speed of 4,162 +/- 276 rpm immediately after implant. Hemolysis was <10 mg/dl and activated partial thromboplastin time (aPTT) values were in the normal range for sheep (<52 sec) after 48 hr of pumping. Liver enzyme concentrations returned to normal within 2 weeks. There was no evidence of thrombocytopenia. No signs of infection were present during assist and none was found at autopsy. The device was successfully removed three times without the use of pressor agents or blood transfusion. Alarm systems performed appropriately. During the 106 days of cumulative pumping, two sheep showed small (<1.5 cm) renal infarcts. Both were associated with intervals of pump stasis. The AB-180 CSS pump was easily implanted into the left chest without the use of cardiopulmonary bypass. It appears to have a low thromboembolic potential in sheep, without the need for large doses of heparin to elevate aPTT values. This characteristic may ameliorate the excessive bleeding seen clinically with current LVAD systems used for post cardiotomy cardiogenic shock, which require anticoagulation with heparin. The small size and weight of the device permit implantation within the chest and allow chest closure. This may reduce the incidence of infection associated with temporary left ventricular assist and an open sternum.

Atrioventricular valve function after single patch repair of complete atrioventricular septal defect in infancy: How early should repair be attempted?

Background: Though repair of complete atrioventricular septal defect in infancy has become routine at most centers, it is not unusual for very young infants to be managed medically because of concerns about the fragility of the atrioventricular valve tissue. Methods: Since July 1992, seventy-two infants have undergone primary repair of complete atrioventricular septal defects at a median age of 3.9 months (40% < 3 months). A single-patch technique was used in all patients. The cleft was closed completely in 61 patients and partially ( n = 10) or not at all ( n = 1) in select patients at risk for valve stenosis. Left atrioventricular valve annuloplasty was performed in 18 patients. On the basis of transesophageal echocardiographic findings, 10 patients were returned to bypass for revision of the valve repair. Results: There was one early death in a patient with single left papillary muscle, no early reoperations, and no new permanent arrhythmias. Only three patients had moderate left atrioventricular valve regurgitation at discharge. During a median follow-up of 24 months, there was one late death and five reoperations for left atrioventricular valve regurgitation ( n = 2) and/or systemic outflow obstruction ( n = 4). Follow-up left atrioventricular valve regurgitation was moderate in three patients, mild in 14, and none/trace in 54. Age had no relation to postoperative atrioventricular valve regurgitation, death, or reoperation. Conclusions: Despite concerns about fragility of valve tissue in very young patients, excellent results can be achieved with meticulous techniques. From neonates to older infants, age at repair does not influence outcome or valve function. (J Thorac Cardiovasc Surg 1998; 115:1032-40)

Diagnostic value of transesophageal echocardiography in the assessment of congenitally corrected transposition of the great arteries in adult patients

This study was designed to evaluate the relative diagnostic values of transthoracic (TTE) and transesophageal (TEE) echocardiography in the assessment of congenitally corrected transposition of the great arteries in adult patients. Twelve patients (mean age 29 years, range 21 to 39 years) with congenitally corrected transposition of the great arteries underwent both TTE and TEE examinations to assess this complex cardiac lesion. Of the 12 patients evaluated, situs solitus and inversus were present in 8 and in 4 patients, respectively. TTE correctly identified atrial situs in only 10 patients, whereas TEE, directly evaluating the morphologic features of either appendage, correctly determined situs in every patient. In all 11 patients with intact inlet ventricular septum, the spatial relationship between the septal leaflets of atrioventricular valves was correctly evaluated by both techniques. However, the chordal attachments of both valves were clearly elucidated by TEE in all patients, whereas TTE could obtain images of these in only three patients. TTE was able to evaluate the discordant connection between the right ventricle and the anterior vessel (aorta) in 10 patients, whereas the connection between the left ventricle and the posterior vessel was clearly shown only in 7 patients. Transesophageal longitudinal planes better elucidated these two discordances in all patients irrespective of the position of the heart in the chest and atrial situs. Four patients had an associated ventricular septal defect (inlet defect in one, perimembranous in two, and muscular in one); the inlet defect was unrestrictive and could be easily detected by either imaging technique, whereas the membranous was detected by TTE and by the horizontal transesophageal planes; the muscular defect was recognized only by TTE. Three patients had an associated pulmonary stenosis; Doppler transthoracic echocardiography showed a left outflow peak gradient of 100 mm Hg in two patients and of 80 mm Hg in one but failed to adequately assess the morphologic features of the stenosis, whose features were clearly visualized by transesophageal longitudinal planes in all patients. In conclusion, in our experience TEE is superior to transthoracic imaging in studying congenitally corrected transposition of the great arteries in adult patients; the horizontal plane is best suited to the evaluation of atrial situs and the atrioventricular junction, whereas the longitudinal plane is most valuable in the study of the morphologic features of the ventriculoarterial connections. These findings should be equally applicable to multiplane transesophageal studies. (Am Heart J 1998;135:43-50.)

Surgical approaches for double-outlet right ventricle or transposition of the great arteries associated with straddling atrioventricular valves

The surgical management of patients with double-outlet right ventricle or transposition of the great arteries and straddling atrioventricular valves remains a subject of controversy. Biventricular repair has theoretic advantages because it establishes normal anatomy and physiology. In some instances, however, it seems to carry too high operative risk, and a univentricular heart repair is preferred. Since 1984, we have operated on 34 patients with double-outlet right ventricle (n = 15) or transposition of the great arteries (n = 19) with isolated straddling tricuspid valve (n = 17), isolated straddling mitral valve (n = 9), both mitral and tricuspid straddling (n = 2), or abnormal insertion of tricuspid (n = 7) or mitral (n = 2) chordae in the left ventricular outlet, precluding an adequate tunnel construction. Straddling was categorized according to the location of the papillary muscle insertion in the opposite ventricular chamber: type A, on the edge of the ventricular septal defect (n = 14); type B, on the opposite side of the ventricular septum away from the edge of the defect (n = 8); type C, on the free wall of the opposite ventricular chamber (n = 8). Abnormal chordal insertions were classified according to the location of their attachments around the edges of the defect. Three types of chordal distribution were identified: on the aortic conus, on the pulmonary conus crossing the ventricular septal defect, or around the defect closing it like a curtain. All but three patients had two ventricles of adequate size. Sixteen patients underwent palliation. Median age at the definitive operation was 6.5 months (range 1 to 130 months). Thirty patients underwent a biventricular repair and four had a univentricular repair. Biventricular repair was achieved by an arterial switch operation in 18 patients and by tunnel construction from the left ventricle to the aorta in 12. In isolated straddling of types A and B, the ventricular septal defect was closed by adjusting the septal patch on the ventricular side above the straddled papillary muscle. In type C, the patch was sewn over the papillary muscle by applying it on the septum. In double straddling, the ventricular septum was incised between the two papillary muscles, and an ellipsoid patch was used to reconstruct the septal defect, directing each subvalvular apparatus into its own ventricular chamber. When the abnormal chordae in the left outflow tract inserted on the aortic or pulmonary conus, the conus was incised and tailored to make a flap, leaving an unobstructed left ventricular outflow tract. In two patients the subvalvular apparatus was resected and reattached to the patch. Curtainlike chordae were a contraindication to biventricular repair in double-outlet right ventricle but not in transposition. There were four early deaths and one late death, all occurring in the group having biventricular repair. Death was due to myocardial ischemia (n = 1), right ventricular hypoplasia (n = 1), pulmonary hypertension (n = 1), and residual subaortic stenosis (n = 1). Two patients had moderate to severe postoperative atrioventricular valve incompetence, caused by a cleft in the mitral valve in one patient. Three patents were reoperated on for subaortic stenosis (n = 1), pulmonary stenosis (n = 1), and mitral regurgitation (n = 1). Mean follow-up of 30.7 ± 19.4 months was achieved in the survivors. All but one patient (univentricular repair) were in New York Heart Association class I, without atrioventricular valve incompetence. Actuarial survival at 4 years was 85.3% ± 3%. We conclude that straddling or abnormal distribution of chordae tendineae of the atrioventricular valves does not preclude biventricular repair in double-outlet right ventricle or transposition of the great arteries provided that the ventricles are of adequate size. Curtainlike abnormal tricuspid chordae remain a contraindication to biventricular repair in double-outlet right ventricle. (J T horac C ardiovasc S urg 1996;111:527-35)

Selection and identification of standard cardiac views from three-dimensional volume scans of the fetal thorax.

The feasibility of fetal echocardiographic examination using three-dimensional ultrasonography was investigated in 54 healthy pregnant women with uncomplicated pregnancies between 17 and 37 weeks of gestation. In 46 cases (85.2%), good quality three-dimensional volumes of the fetal heart were obtained from both apical and lateral four-chamber views. By reslicing apical volumes, the reformatted sections of the long axis view of the left ventricle and the aortic crest were seen in 40 (87%) and 38 (83%) of 46 cases, respectively. The short axis was seen in 26 (57%) and ductal arch in 30 (65%) cases. The examination of lateral volumes was much less successful. The short axis was seen in 11 (24%) cases, and the aortic crest in 22 (48%), whereas the analysis of the longitudinal views was not possible. The best results were obtained at a gestational age between 22 and 27 weeks. Three-dimensional fetal echocardiography allowed the examination of the four chambers of the heart and left outflow tract during the late second trimester. The technique may become useful for the screening and diagnosis of congenital cardiac defects in the future.

954-7 Cardioversion of Atrial Flutter: Atrial Appendage Stunning and Thromboembolic Potential. A Transesophageal Echocardiographic Study

Cardioversion (CV) of atrial arrhythmias is commonly performed. Pericardioversion anticoagulation is not recommended in patients with atrial flutter (AFL) as it is assumed that the thromboembolic potential of atrial flutter is extremely low. To determine the thromboembolic potential of patients with atrial flutter undergoing cardioversion, we performed transesophageal echocardiography (TEE) in 26 consecutive patients (25 electrical and 1 pacing) immediately prior to and immediately after cardioversion. 2 patients experienced cerebrovascular events within 24 hours of cardioversion despite the absence of thrombi on the precardioversion TEE. Peak left atrial appendage outflow (LAA+) and inflow velocities (LAA-, cm/sec) prior to (PRE) and after (POST) cardioversion were documented (mean ± SD): LAA+ LAA- PRE CV 53 ± 19.6 53.2 ± 20.6 POST CV 30 ± 16.1 38.7 ± 18.1 p &lt; 0.0001 0.0001 92% of patients demonstrated a reduction in LAA+; 58% of patients had a greater than 50% decrease in LAA+. 50% of patients developed new or increased spontaneous echo contrast after cardioversion. Both patients with new cerebrovascular accidents demonstrated marked reductions in LAA+ and increased spontaneous echo contrast. Patients undergoing CV of AFL have evidence of significant left atrial appendage stunning. Stunning after CV as evidenced by decreased left atrial appendage velocities and increased spontaneous echo contrast is common and associated with thromboembolism. Anticoagulation should be considered in patients undergoing CV of atrial flutter with high risk TEE indices.

Relations between left atrial appendage blood flow velocity, spontaneous echocardiographic contrast and thromboembolic risk in vivo

Objectives. The aim of this study was to determine the relations between spontaneous echo contrast, left atrial appendage blood flow velocity and thromboembolism.Background. Left atrial thrombus and spontaneous echo contrast, a putative marker of thromboembolic risk, are frequently located in the left atrial appendage. Measurement of left atrial appendage outflow Doppler velocity by transesophageal echocardiography is a recent technique for assessment of left atrial appendage function, which may be important in thrombus formation.Methods. Transthoracic and transesophageal echocardiographic studies were performed in 140 patients with atrial fibrillation (chronic in 80 patients, paroxysmal in 50 patients, first episode <2 weeks in 10 patients). The left atrium and appendage were inspected for thrombus and spontaneous echo contrast, which was graded from 0 (none) to 4+ (severe). Outflow velocity profiles were obtained by pulsed wave Doppler at the orifice of the left atrial appendage.Results. Left atrial spontaneous echo contrast was present in 78 patients (56%). In multivariate logistic regression analysis, spontaneous echo contrast was the only significant correlate of left atrial thrombus and was present in 14 (93%) of 15 patients. Spontaneous echo contrast and age were associated positively, and anticoagulant therapy was associated negatively, with previous thromboembolic events. Increasing grades of spontaneous echo contrast were associated with decreasing left atrial appendage blood velocity. The velocity in patients with thrombus was not significantly different from that in patients with 4+ spontaneous echo contrast. In multivariate linear regression analysis, the grade of spontaneous echo contrast was significantly and negatively associated with left atrial appendage velocity (p = −0.0001) and mitral regurgitation (p = −0.0002) and significantly and positively associated with left atrial area (p = 0.0005). The odds ratio for spontaneous echo contrast was 28:1 for low left atrial appendage blood flow velocity (<35 cm/s) and 96:1 for low velocity and the absence of mitral regurgitation.Conclusions. Spontaneous echo contrast is the cardiac factor most strongly associated with left atrial appendage thrombus and embolic events. Spontaneous echo contrast formation is promoted by reduced blood flow velocity and increased left atrial size but is diminished by mitral regurgitation.

Systolic intra-cavitary gradients following aortic valve replacement: an echo-Doppler study

Systolic left ventricular flow was studied by pulsed and continuous wave Doppler in 41 patients following aortic valve replacement for severe stenosis (mean valvular area: 0.58 cm2; range 0.3-0.75 cm2). Maximal left ventricular velocities by continuous wave Doppler study, were higher than 2.5 m.s-1 with a sharp peak at end-systole in five patients in basal condition and in four others after amyl nitrite inhalation. Pulsed Doppler study showed that the high velocities started from the apex or mitral papillary muscle level with a marked chamber narrowing at two-dimensional echography. Only one patient had a systolic anterior motion (SAM) of the anterior mitral leaflet with mitral-septal contact. The left ventricular dimensions, as measured by M-mode echography were compared in the various patient groups. High velocities seemed statistically associated with the smaller systolic and diastolic diameters of the left ventricle and outflow tract and the larger relative thickness of the posterior wall. The highest pressure gradients disappeared after correction of hypovolaemia (one patient), clearance of pericardial effusion (one patient), or beta-blocker treatment (three patients). The present study confirms that left intra-ventricular dynamic gradients can occur after clearance of fixed outflow obstruction, for which Doppler examination is a reliable and innocuous diagnostic means. Haemodynamically, this syndrome resembles hypertrophic obstructive cardiomyopathy, but the scarcity of the systolic anterior motion of the mitral leaflets is suggestive of a different mechanism that could be cavity obliteration or mid-ventricular obstruction.

Structural changes in pulmonary vessels and coronary arteries in hypoplastic left heart syndrome

In order to correlate gross morphological features with pulmonary and coronary vasculature changes in hypoplastic left heart syndrome (HLHS) 15 heart-lung necropsy specimens from neonates were analysed. Histology of left atrium wall, lung vessels with pulmonary arteriolar disease morphometric grading, study of intra and extra pulmonary wall veins and coronary arteries were recorded. Classic HLHS was observed in 11, and DORV with mitral atresia in 4, the foramen ovale (FO) being the only left atrium outflow tract in all. All specimens had increased % of thickness and muscular extension of arterioles and increased wall thickness of pulmonary veins, but severer arteriolar and venous changes with left atrium fibrosis were noticed in 8 specimens with either closed FO (3 cases) or mean FO diameter (d) of 5 mm when compared with specimens with mean FOd of 9 mm. Coronary arteries histology disclosed in 4 of 8 specimens with opened but hypoplastic mitral valve, intima proliferative changes with lumen narrowing, not observed in 7 specimens with mitral valve atresia. We concluded that in HLHS closed or restrictive FO and permeable mitral valve may predispose neonates to respiratory complications, right ventricle abnormal function and arrhythmias, specially after cardiac surgery.