Biomedical subjects

M L Rigby

Publications and source records attributed to M L Rigby.

At least 73 records · Page 4Linked to original sources

PubMed1990

Primary balloon dilatation of coarctation of the aorta in neonates.

Primary balloon dilatation of coarctation of the aorta was attempted in 10 consecutive neonates (age range 2-23 days). The coarctation site was crossed and the balloon inflated in all but one patient. In two patients with associated severe isthmal hypoplasia there was no change in the gradient after dilatation. In the remainder, the residual gradients were trivial and angiography showed complete relief of coarctation. Severe recoarctation developed 5-12 weeks after dilatation in five patients, each considered to have had an excellent initial result. The coarctation was rapidly progressive in three patients in whom Doppler studies within two weeks of the development of recoarctation had shown no significant gradient. In the other two patients progressive restenosis was charted by Doppler examinations over the course of 6-8 weeks. Three patients had a second, initially successful, dilatation procedure. One patient remained well with no residual gradient 18 weeks later. Stenosis recurred within eight weeks in the other two, and both have undergone successful surgical repair. Balloon dilatation of a native coarctation of the aorta gave excellent immediate results in most neonates. Severe isthmal hypoplasia is, however, a contraindication to balloon dilatation and early restenosis is an important problem. These results do not support the continued use of primary balloon dilatation of coarctation of the aorta in neonates.

Aorta, Thoracic↗

PubMed1990

Plasma concentration of atrial natriuretic peptide in spontaneous atrioventricular re-entrant tachycardias of childhood.

Plasma atrial natriuretic peptide was measured in 13 children between the ages of 1 week and 2 years 9 months during atrioventricular re-entrant tachycardia and 15 minutes after the restoration of sinus rhythm. There was a significant decline in atrial natriuretic peptide during sinus rhythm. Plasma concentrations of the peptide were significantly higher during tachycardia in seven infants under 1 year than in the six older children. The heart rates and the duration of tachycardia were not significantly different in the two age groups. Cardiac failure was present in five of seven children under 18 weeks of age during tachycardia but in none of the older children. The plasma concentration of atrial natriuretic peptide did not significantly correlate with duration of tachycardia or heart rate. If tachycardia occurs in young infants the low functional reserve capacity of the developing heart leads to cardiac failure more frequently and it is likely that this was the cause of the significantly higher plasma concentration of atrial natriuretic peptide in the younger children.

Adenosine↗

PubMed1990

Tetralogy of Fallot with anomalous pulmonary venous connections: a rare but clinically important association.

Anomalous pulmonary venous connections were found in seven (0.6%) of 1183 patients with tetralogy of Fallot. Three patients had totally anomalous connections (one supracardiac, one direct to coronary sinus, and one mixed supracardiac and infracardiac) and four patients had partially anomalous pulmonary venous connections. All patients presented with the clinical features of tetralogy of Fallot. Anomalous pulmonary venous drainage was suspected clinically in only one patient in whom there was a scimitar sign on the chest radiograph. The exact diagnosis was established by cross sectional echocardiography (one), preoperative or postoperative angiography (five), or at necropsy (one). Surgery was performed in six patients. Total correction without re-routing of the anomalously draining veins was successful in all those with partially anomalous connections, with no significant long term sequelae (follow up median 17 years). Of those with totally anomalous connections, the full diagnosis was made only at necropsy in one patient, successful one-stage correction was performed in one, and the other patient, who had partially obstructed mixed drainage, died shortly after one-stage correction. Histological examination of the lung biopsy specimen in this patient showed grade 2 pulmonary vascular disease. Tetralogy of Fallot with anomalous pulmonary venous connections is a rare association. Careful preoperative assessment is required in those with totally anomalous connections.

Abnormalities, Multiple↗

PubMed1990

Options for surgical repair in hearts with univentricular atrioventricular connection and subaortic stenosis.

Thirteen patients have undergone surgical treatment because of subaortic obstruction in hearts with a univentricular atrioventricular connection. Nine patients underwent surgical enlargement of the ventricular septal defect and four patients had construction of an aortopulmonary anastomosis and closure of the pulmonary trunk (the Damus-Kaye-Stansel procedure). Two patients undergoing enlargement of the septal defect and two having the Damus-Kaye-Stansel procedure also had a modified Fontan procedure. One patient had complete atrioventricular dissociation after direct enlargement of the ventricular septal defect, which necessitated insertion of an epicardial pacemaker. One patient died within 30 days of the operation after enlargement of the defect and two patients after the Damus-Kaye-Stansel procedure. There was one late death, occurring in a patient who underwent enlargement of the ventricular septal defect. Ten patients have subsequently undergone conventional cardiac catheterization and angiography or transcutaneous Doppler flow studies to assess the relief of the subaortic obstruction. The result has been satisfactory in all. Because of this experience, we now recommend direct surgical enlargement of the restrictive ventricular septal defect for direct relief of subaortic stenosis occurring with a univentricular atrioventricular connection to a dominant left ventricle, inasmuch as it appears to be hemodynamically effective with a low operative mortality and morbidity. The Damus-Kaye-Stansel procedure can also have a role in relieving subaortic stenosis when the atria are connected to a dominant right ventricle.

Aortic Valve Stenosis↗

PubMed1989

Cross-sectional echocardiography.

Cross-sectional echocardiography has become an essential part of the investigation of infants and children with heart disease. Frequently, it provides a precise diagnosis. In many instances, particularly in neonates and infants, surgery can be undertaken without the need to proceed to cardiac catheterisation. Although cross-sectional echocardiography provides little information about pulmonary or systemic vascular resistance and flow, considerable information about the latter can be established by Doppler. Echocardiography is essentially the representation of cardiac morphology in life. This technique can, therefore, readily be used in sequential segmental analysis of all patients.

Child↗

PubMed1989

Cross sectional echocardiography for recognition of ventricular topology in atrioventricular septal defect.

The cross sectional echocardiograms of 150 children with atrioventricular septal defects were reviewed to determine the spatial orientation of the ventricles. In 125 cases with usual atrial arrangement (situs solitus), ventricular topology showed the right hand pattern. Of the 25 patients with atrial isomerism, 13 had similar right hand topology but 12 (48%) had the left hand pattern. This finding was more common in hearts in the right side of the chest (dextrocardia), but there was no significant correlation between ventricular topology and number of atrioventricular valves or the ventriculoarterial connection. In part because of inferences for disposition of the conducting tissue, knowledge of ventricular topology is important when operation for atrioventricular septal defects is considered. Ventricular topology can be promptly recognised by cross sectional echocardiography.

Echocardiography↗

PubMed1989

Efficacy and safety of adenosine in the treatment of supraventricular tachycardia in infants and children.

One hundred and seventeen episodes of supraventricular tachycardia in 50 children, including 28 infants, were treated with intravenous adenosine. Adenosine was prepared in a sterile solution of 0.9% saline (1 mg/ml) and given in incremental doses of 0.05 mg/kg every two minutes to a maximum of 0.25 mg/kg. Ninety of the 117 episodes were terminated. This included 88 of the 102 episodes of junctional tachycardia (79 of the 92 episodes of atrioventricular reentry tachycardia, seven of the eight episodes of atrioventricular nodal reentry tachycardia, and both of the episodes of long R-P' tachycardia). Only one of four episodes of His bundle tachycardia and one of the eight episodes of ectopic atrial tachycardia were terminated. None of the three episodes of atrial flutter were terminated. Side effects were frequent but mild and included transient complete atrioventricular block (less than 6 s), sinus bradycardia (less than 40 s), ventricular extrasystoles, flushing, nausea, headache, and respiratory disturbance. Reinitiation (within 5 s) of supraventricular tachycardia occurred in 13 of the terminated episodes. Although reinitiation limited its clinical efficacy in some patients, intravenous adenosine offered a safe and efficient method of rapid termination of most episodes of supraventricular tachycardia and in some cases facilitated diagnosis of the mechanism.

Adenosine↗

PubMed1989

Right ventricular function 10 years after the Mustard operation for transposition of the great arteries: analysis of size, shape, and wall motion.

Biplane right ventriculograms were obtained in 18 symptom free patients 109 (26) months (mean (SD)) after Mustard repair of transposition of the great arteries. Ventricular size, shape, and wall motion were measured from the digitised angiograms and compared with previously published data on left ventricular function after anatomical correction of transposition of the great arteries, with right ventricular function in controls, and with patients before repair of tetralogy of Fallot. Global indices of ventricular function were depressed after Mustard repair and wall motion abnormalities were common. The presence of wall motion abnormalities in this group was associated with a reduction in ejection fraction and ventricular filling rates. In four of five patients in whom an appropriate preoperative angiogram was available a similar pattern of wall motion was seen before the Mustard operation, suggesting that preoperative events may be important in determining eventual outcome.

Child↗

PubMed1989

Morphological nature of the atrioventricular valves in hearts with double inlet left ventricle.

The rudimentary right ventricle in hearts with double inlet to a dominant left ventricle can exist either to the right or the left side of the ventricular mass. These variants have been interpreted to imply differences in ventricular topology. If correct, they also imply that differences should exist in the morphology of the atrioventricular valves, previously thought to be indistinguishable one from the other. To test this possibility, we examined 15 hearts with double inlet to a morphologically left ventricle and 10 normal hearts. The distinguishing features of normal valves were evaluated for their consistency, and the most reliable were employed for interpreting the valves in the abnormal hearts. As shown by previous echocardiographic studies, insertion of valvar tension apparatus to the interventricular septum was unique to the morphologically tricuspid valve. Ten of the abnormal hearts had one valve showing this feature, it being absent in the other valve. The attachment, consistently on the same side as the rudimentary right ventricle, could be of diagnostic value in determining ventricular topology. In our small study, nonetheless, this approach still leaves one third of the hearts in which topology cannot be ascertained with certainty and in which it is not possible to distinguish the morphological nature of the atrioventricular valves.

Echocardiography↗

PubMed1988

Surgical risk factors in total anomalous pulmonary venous connection.

Eighty-three patients underwent surgical correction of total anomalous pulmonary venous connection (TAPVC) between 1973 and 1986. There were 46 boys and 37 girls. Median age at operation was 60 days (1 to 240) and median weight 3.9 kg (1 to 22). The anatomic types encountered included infracardiac connection (16 patients), supracardiac connection (32) and pulmonary venous drainage connected directly to the coronary sinus (27). Mixed anomalous drainage or pulmonary venous return connected directly to the right atrium occurred in 8 patients. Diagnosis was established by cardiac catheterization and angiography (56 patients), clinical examination (3) and cross-sectional echocardiography alone in 24 of the last consecutive 28 patients. Pulmonary hypertension was present in 26 (55%) of those who underwent cardiac catheterization. The median pulmonary vascular resistance was 4.2 units/m2 (body surface area) for all the patients, whereas in those with infracardiac pulmonary venous connection the median value was 10 units/m2. The median interval between admission and operation was 72 hours. Surgical correction was performed using profound hypothermia and circulatory arrest in 68; for the remainder, conventional cardiopulmonary bypass with profound to moderate hypothermia was used. Ten patients developed 1 or more pulmonary hypertensive crises during the early postoperative period. These were diagnosed in 8 by direct pulmonary artery pressure measurement and in 2 by clinical examination. Late reoperation was necessary in 6 patients (10%). Analyses of risk factors for 30-day survival for all patients showed that the risk of early death was associated with the type of anomaly (infradiaphragmatic), occurrence of pulmonary hypertensive crises, year of the operation, set of the patient and pressure of preoperative congestive heart failure.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Pressure↗

PubMed1988

Characterisation of the normal right ventricular pressure-volume relation by biplane angiography and simultaneous micromanometer pressure measurements.

The normal right ventricular pressure-volume relation was studied by recording biplane right ventriculograms with simultaneous high fidelity pressure recordings in 10 adults found to have normal coronary arteries and haemodynamic function at diagnostic cardiac catheterisation. Right ventricular volume was measured frame by frame from digitised ventriculograms by a modification of Simpson's rule. The accuracy of this method was tested in a study of 22 human and animal right ventricular casts. There was excellent agreement between calculated volumes and those measured by fluid displacement. The derived regression equations were used to correct right ventricular volumes calculated from in vivo studies. The mean (SD) end diastolic volume index for the group was 62 (13) ml/m2, the stroke volume index was 43 (8) ml/m2, and the ejection fraction was 62 (6)%. Right ventricular pressure-volume loops were generated by combining simultaneous volume and pressure curves. The normal right ventricular pressure-volume loop was triangular, departing significantly from the square or rectangle of the normal left ventricular pressure-volume loop. Ejection from the right ventricle began early during the pressure rise and continued as right ventricular pressure fell. As a result phases of isovolumic contraction and relaxation were difficult to define. These observations show that normal right ventricular pressure-volume relations differ considerably from those of the normal left ventricle, presumably reflecting the different loading conditions of the two ventricles.

Adult↗

PubMed1988

Intermediate to late term results of Mustard's procedure for complete transposition of the great arteries with an intact ventricular septum.

Overall survival after Mustard's operation was assessed in 130 patients with complete transposition of the great arteries and an intact ventricular septum who were operated on at the Brompton Hospital in the 12 year period from January 1974 to December 1985. Actuarial analysis showed a survival at five years of 79.1% (25 deaths in 130 patients). Half the deaths occurred within a month of operation and half up to five years later. Operation under the age of three months carried a greater mortality (six deaths in 11 patients). Statistical analysis showed that these survival figures were consistent throughout the series and did not alter with the year of operation. In the light of recent trends in treatment of this lesion, it is concluded that for neonates an arterial switch procedure is now likely to carry the best chance of long term success. For the patient who presents after the age of three months, however, there may still be a place for the Mustard procedure.

Age Factors↗

PubMed1988

A new technique for the assessment of pulmonary regurgitation and its application to the assessment of right ventricular function before and after repair of tetralogy of Fallot.

Biplane right ventriculograms with simultaneous high fidelity pressure recordings were obtained in 24 patients with tetralogy of Fallot. Twelve patients were studied before repair and 12 were studied 67 (42) months after radical surgical repair without the use of a transannular patch. In the patients who had repair right ventricular end diastolic and end systolic volume indices were higher, and the ejection fraction was lower. Time to peak ventricular filling and the peak rate of ventricular fillings were also lower in this group and there was a significant relation between peak filling rate and ejection fraction. Postoperative pressure-volume loops from nine patients showed an increase in cavity volume during the decline in right ventricular pressure, which indicated pulmonary regurgitation. The mean regurgitant volume for the group correlated with end diastolic volume index, stroke volume index, and peak filling rate, but not with ejection fraction. These data show that both systolic and diastolic abnormalities of right ventricular function are detected in most patients after radical repair of tetralogy of Fallot. The reduction of ejection fraction previously reported in these patients is unrelated to the degree of pulmonary regurgitation and primarily reflects an impairment of contractile function that presumably is related to intraoperative events.

Blood Pressure↗

PubMed1988

Left ventricular function in double inlet left ventricle before the Fontan operation: comparison with tricuspid atresia.

Fourteen patients with double inlet left ventricle and nine patients with tricuspid atresia had biplane left ventricular angiography with simultaneous measurement of left ventricular pressure by micromanometer. Age distribution, haemodynamic function, and previous palliative operation were similar in the two groups. Left ventricular volumes were calculated frame by frame throughout the cardiac cycle by Simpson's rule. The end diastolic volume index was similar in the two groups, but the ejection fraction was significantly lower in tricuspid atresia. Left ventricular peak filling and emptying rates were also lower in tricuspid atresia, although heart rates in the two groups were similar. End diastolic shape index was significantly higher in patients with tricuspid atresia, indicating a more globular shape, and changed less during systole, suggesting differences in the mechanism of ejection between the two groups. Analysis of pressure-volume loops showed normal phase relations between pressure and volume, but systolic stroke work was reduced in tricuspid atresia and correlated with stroke volume and shape change. Left ventricular function was impaired in patients with tricuspid atresia when compared with those with double inlet left ventricle and this finding may reflect structural differences caused by the absence of one atrioventricular connection.

Adolescent↗

PubMed1987

Survival after balloon atrial septostomy for complete transposition of great arteries.

Mortality before surgery must be taken into account when comparing the surgical mortality of atrial redirection procedures (Mustard's or Senning's operation) and the arterial switch operation for patients with complete transposition. This is because the switch operation is usually performed within the neonatal period or early infancy but Mustard's or Senning's operation usually after 4 months of age. The outcome of balloon atrial septostomy was therefore assessed in all 102 infants with transposition of the great arteries (plus or minus associated anomalies) who underwent the procedure at our hospital in the 10 years from January 1975 to December 1984. We considered the procedure to have been unsuccessful if the patient died from any cause (including other surgical procedures) between the septostomy and subsequent interatrial repair (Mustard's operation) or arterial switch operation. Eighteen patients died, although in only two was this as a direct result of the septostomy. Statistical analysis showed that low weight, presence of a persistent arterial duct, and coarctation of the aorta were significant risk factors. Early survival of infants with transposition of the great arteries has been dramatically improved after the introduction of balloon atrial septostomy. Nevertheless, there is considerable attrition before definitive repair, which must be included in the prediction of overall outcome.

Body Weight↗

PubMed1987

Reversed offsetting of the septal attachments of the atrioventricular valves and Ebstein's malformation of the morphologically mitral valve.

Ebstein's anomaly of the tricuspid valve is characterised by downstream displacement of the tricuspid leaflets. In the case of the septal leaflet, the result is exaggerated offsetting of the atrioventricular valves. Thus it might be supposed that in Ebstein's anomaly of the mitral valve, downstream displacement of the aortic (septal) leaflet of the mitral valve could move its attachment beyond that of the tricuspid valve, resulting in reversed offsetting. To examine this hypothesis three patients each with a concordant atrioventricular connection were studied. The first, with Marfan's syndrome and without an abnormal mitral valve, had reversed offsetting shown by echocardiography. The second, without Marfan's syndrome and with Ebstein's anomaly of the mitral valve, showed echocardiographically normal offsetting but a displaced mural leaflet. The third, in whom Ebstein's anomaly of the mitral valve was confirmed at necropsy, showed all the features of the second case, with normal offsetting of the atrioventricular valves. Thus reversed offsetting is not a feature of Ebstein's anomaly of the mitral valve and in the first case this feature was caused by upward displacement of the tricuspid valve secondary to dilation of the aortic root.

Abnormalities, Multiple↗

PubMed1986

Diagnosis and significance of atrial isomerism.

Fifty-one patients at the Brompton Hospital were identified as having either right or left atrial isomerism by reviewing the records and catheterization, echocardiographic and, in 17 cases, autopsy data. Every study patient had 1 or more of the following conditions: isomeric bronchial anatomy; angiographic or necropsy evidence of atrial anatomy; echocardiographic diagnosis of isomerism; and anomalies of systemic or pulmonary venous connection. Patients with anomalous venous connections all had additional signs of isomerism. Neither right nor left type was predominant in either sex. The heart was in the left chest slightly more often than the right. Abdominal visceral heterotaxy was the most frequent radiographic finding. An ambiguous and biventricular connection was the commonest type of atrioventricular (AV) connection in left isomerism. A common AV valve was the most frequent mode of connection in both forms. Univentricular AV connection, double-outlet right ventricle, pulmonary atresia and discordant ventriculoarterial connection were commoner in right isomerism. Left isomerism is associated with much longer survival, its constellation of associated malformations frequently being less severe and more amenable to corrective surgery. A precise diagnosis must be made during life in order to select the most appropriate treatment.

Bronchi↗

PubMed1986

Anatomical correction for complete transposition and double outlet right ventricle: intermediate assessment of functional results.

Thirty three patients were followed up after anatomical correction of transposition of the great arteries or double outlet right ventricle and subpulmonary ventricular septal defect (Taussig-Bing anomaly). There were no late deaths and clinical progress was excellent. Cardiac catheterisation was performed in 17 patients two weeks to 44 months after operation. There were six patients with simple transposition, six with complete transposition and large ventricular septal defect, and five with the Taussig-Bing anomaly. Pressure gradients across the right ventricular outflow tract ranged from 5 to 72 mm Hg, being greater than 40 mm Hg in five patients. No patient was shown to have important valvar regurgitation and in 15 patients the coronary anastomoses were widely patent. Left ventricular function was assessed from digitised ventriculograms. Ventricular volume, shape, and ejection fraction were all normal for the group although patients with complex transposition showed a significantly lower mean (SD) ejection fraction than those with simple transposition (62(9) vs 77(9]. Analysis of regional wall motion showed a totally normal pattern in four patients; however, in seven patients a characteristic abnormality of anterior hypokinesis with delayed onset of inward wall motion was seen. Anatomical correction of transposition of the great arteries and the Taussig-Bing anomaly can be performed with satisfactory anatomical and functional results. The implications of the left ventricular wall motion abnormalities is unknown.

Angiography↗