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The double switch operation with accent on the Senning component.

In congenitally corrected transposition (ccTGA) the most common configuration is atrial situs solitus with left ventricular loop and left transposition of the great arteries (SLL). Less common is ccTGA with atrial siti inversus (IDD). In both configurations there is a high incidence of ventricular septal defect, pulmonary stenosis, or atresia and some anatomic abnormality of the morphologic tricuspid valve (mTV). The morphologic right ventricle (mRV) is the systemic ventricle and prone to premature failure, particularly in the presence of early TV regurgitation, atrial arrhythmias conduction defects, and prior surgical ventricular septal defect closure. With a long experience with the Senning operation and then the arterial switch, it seemed feasible that these could be combined in ccTGA to restore the mLV to the systemic circuit. This was first attempted in 1989 by the author and was successful. Many of the more recently graduated congenital heart surgeons have little or no experience with the inflow switch. For this reason, the author was asked to write this article, accenting the technical details of the inflow switch. The author uses the Senning operation, with those modifications needed to accommodate the differences between the morphologic right atrium, conduction system, and quite frequent discordance between the atrial situs and the position of the apex of the heart, in ccTGA as compared with TGA.

Cardiac Surgical Procedures↗

Transposition of the great arteries. Successful Senning's operation in 35 consecutive patients.

Mustard's operation for TGA (transposition of the great arteries) has been obstructive complications. In order to try to avoid these complications, we used Senning's operation for TGA. Our experience in 35 consecutive cases is reported. There were no operative or late deaths. Four patients had a PDA; three had a significant VSD with subpulmonary stenosis in two. Previous atrial septectomy and persistent LSVC did not represent contraindications to this procedure. The postoperative course has been smooth and uneventful in all patients. Follow-up periods of one to twenty months demonstrated sinus rhythm in all patients and there were no significant gradients between the venae cavae and the new systemic atrium in 12 reinvestigated patients. On the basis of these results, Senning's operation is recommended as a valid alternative to Mustard's operation.

Cardiac Catheterization↗

Combined arterial switch and Senning operation for congenitally corrected transposition of the great arteries: patient selection and intermediate results.

OBJECTIVE: Late results after traditional methods of repair of congenitally corrected transposition of the great arteries are poor. The combined arterial switch and Senning (double switch) operation may improve outcomes by using the morphologically left ventricle and mitral valve in the systemic circulation. In this report we review patient selection and intermediate results after the double switch operation for congenitally corrected transposition of the great arteries. METHODS: Since 1993, a total of 35 patients with congenitally corrected transposition of the great arteries with two ventricles of adequate size and no valvular pulmonary stenosis were potential candidates for a double switch operation. Eleven were not yet in need of further treatment, and 1 died during evaluation. The remaining 23 patients were entered into a protocol leading to anatomic repair. Their hospital records were reviewed, and follow-up data were obtained to evaluate early and intermediate outcomes. RESULTS: The 23 patients were candidates for anatomic repair because of right ventricular dysfunction or tricuspid regurgitation (n = 15) or associated uncorrected defects (n = 8). Pulmonary artery banding was performed in a total of 15 patients, either for left ventricular retraining (n = 11) or for congestive heart failure (n = 4). In 2 patients, aged 12 and 14 years, retraining was unsuccessful because of left ventricular dysfunction. Four patients with banding are currently awaiting repair. Eight patients proceeded to undergo double switch operations without preliminary pulmonary artery banding. To date, 17 patients have undergone double switch operations, with no early or late mortality. One patient required cardiac transplantation for progressive left ventricular failure after a preliminary banding and double switch operation done at 7 years of age. Ventricular function and tricuspid regurgitation remained stable or improved in all other cases. No patient has surgically acquired arrhythmias or significant residual hemodynamic conditions. All patients are alive and clinically well at a mean follow-up of 36 months (range 1 month-8 years). CONCLUSIONS: Congenitally corrected transposition of the great arteries with a normal pulmonary valve and two adequate ventricles can be managed with combined arterial switch and Senning operation with excellent intermediate results. Reconditioning the left ventricle may not be suitable for older patients. Late follow-up will be necessary to determine whether this management strategy provides a survival advantage for these patients.

Algorithms↗

Is SENS a farrago?

SENS (Strategies for Engineered Negligible Senescence) is a panel of proposed interventions in mammalian aging that I have suggested may be sufficiently feasible, comprehensive, and amenable to subsequent incremental refinement that it could prevent death from old age (at any age) within a time frame of decades, leading to four-digit lifespans of many people alive today. This extreme conclusion has drawn sharp criticism from some colleagues, especially because the methodology of SENS departs radically from approaches generally considered the most promising ways to combat aging and because it is perceived as endangering biogerontology's respectability. Here I briefly respond to these criticisms.

Aging↗

Risk of complications during pregnancy after Senning or Mustard (atrial) repair of complete transposition of the great arteries.

AIMS: To investigate magnitude and determinants of risks during pregnancy in women with Mustard or Senning repair for complete transposition of the great arteries (TGA). METHODS AND RESULTS: Using a nationwide registry (CONCOR), 70 women with Senning (23%) or Mustard (77%) repair for TGA were enrolled. A total of 28 patients had 69 pregnancies (two twins), including 17 spontaneous miscarriages and three elective abortions. During 39 of the 49 completed pregnancies, complications were observed. The most important cardiac complication was clinically significant arrhythmia (n=11, 22%), especially occurring in patients with a prior history of arrhythmia. Important general pregnancy complications were preeclampsia (n=5, 10.2%) and pregnancy-induced hypertension (n=4, 8.2%). Obstetric complications included premature rupture of membranes (n=7, 14.3%), premature labour (n=12, 24.4%), premature delivery (n=16, 31.4%), and thrombo-embolic complications (n=2, 4.1%). Mean (singleton) pregnancy duration was 36+/-5 weeks. Eleven of the 51 children (21.6%) were small for gestational age. Foetal and neonatal mortality combined was 11.8% (n=6). No recurrence of congenital heart disease in the offspring was documented. CONCLUSION: In this largest report on pregnancy in women with atrial-corrected TGA to date, a high incidence of obstetric complications and mortality in the offspring was observed.

Abortion, Spontaneous↗

Prevalence of the sat, set and sen genes among diverse serotypes of Shigella flexneri strains isolated from patients with acute diarrhoea.

New virulence factors associated with the genus Shigella have been described recently. These comprise enterotoxins ShET-1 and ShET-2, encoded by the set and sen genes, respectively, and the secreted autotransporter toxin Sat, encoded by the sat gene. The present study aimed to determine the prevalence of genes encoding these toxins among a collection of Shigella flexneri clinical isolates belonging to different serotypes. While the set gene was detected only in S. flexneri serotypes 2a and 2b, the sen and sat genes were present in diverse serotypes of S. flexneri.

Acute Disease↗

Early results of AV sequential pacing on left ventricular outflow obstruction after Senning procedure.

Dual chamber pacing was shown to decrease left ventricular outflow tract (LVOT) obstruction in patients with hypertrophic cardiomyopathy 30 years ago. We report early results of AV sequential pacing from the LV apex in a patient with transposition of the great arteries who is post-Senning procedure. LVOT obstruction resulted from septal deviation and systolic anterior motion of the mitral valve. Pacing was indicated for sinus node dysfunction. AV sequential pacing with a short optimal AV interval of 60 ms demonstrated a 45% reduction in the degree of LVOT obstruction. This article suggests that LVOT obstruction after the Senning procedure can be palliated by asynchronous septal contraction induced by AV sequential pacing, even if the activation is from LV apex, and avoid or postpone surgery in selected situations.

Adolescent↗

Complex character of senS, a novel gene regulating expression of extracellular-protein genes of Bacillus subtilis.

The senS gene of Bacillus subtilis, which in high copy number stimulates the expression of several extracellular-protein genes, has been cloned, genetically mapped, and sequenced. The gene codes for a highly charged basic protein containing 65 amino acid residues. The gene is characterized by the presence of a transcription terminator (attenuator) located between the promoter and open reading frame, a strong ribosome-binding site, and a strong transcription terminator at the 3' end of this monocistronic gene. The amino acid sequence of SenS showed partial homology with the N-terminal core binding domain region of bacterial RNA polymerase sigma factors and a helix-turn-helix motif found in DNA-binding proteins. The gene can be deleted without any effect on growth or sporulation.

Amino Acid Sequence↗

Late outcome of Senning and Mustard procedures for correction of transposition of the great arteries.

OBJECTIVES: To evaluate late mortality and morbidity after an atrial switch procedure for correction of transposition of the great arteries (TGA) and to assess predictive factors for adverse outcome. SETTING: Tertiary referral centre. DESIGN AND PATIENTS: Retrospective follow up study of 137 patients surviving hospitalisation for TGA atrial switch procedure (Mustard or Senning) in a single institution and divided into two groups (simple and complex) depending on presurgical anatomy. Several surgical and follow up factors were evaluated during 16.7 (5.6) years' follow up. RESULTS: Late mortality was 5.1% (95% confidence interval 1.37% to 8.84%) with sudden death as the most common cause. No significant difference was found between Mustard and Senning procedures and between the complex and simple groups in terms of mortality. Independent predictive factors for late mortality were a history of supraventricular tachyarrhythmias and advanced New York Heart Association (NYHA) functional class during follow up. A very common finding was development of sinus node dysfunction (47.6%), which had no influence on mortality. There was little need for reintervention (5.1%) and relatively few cases of right ventricular systolic dysfunction (14.6%). During follow up, most patients (96.2%) were in NYHA functional class I-II. CONCLUSIONS: Overall long term outcomes of patients with atrial repair of TGA in the present era are encouraging in terms of late mortality and quality of life. Nevertheless, better outcomes may be offered through improved diagnostic methods for right ventricular function and better management of supraventricular tachyarrhythmias.

Adolescent↗

Postoperative hemodynamic and electrophysiological evaluation of the Senning procedure.

To determine efficacy of the Senning procedure for correction of transposition of the great arteries we performed detailed hemodynamic and electrophysiological studies in 6 consecutive children operated upon at 5-18 months of age. Cardiac catheterizations were performed 10-19 months following surgery. All patients were asymptomatic on no medication. Hemodynamic studies demonstrated no evidence of pulmonary venous obstruction, pulmonary hypertension, or left ventricular outflow tract obstruction. 1 patient had mild upper baffle limb obstruction. Angiography demonstrated tricuspid insufficiency in 2 patients and a small atrial level shunt in 1. Ambulatory electrocardiographic monitoring in 5 of 6 patients revealed multiple premature ventricular contractions in 1. Invasive electrophysiological studies for sinus node function were normal. Corrected sinus node recovery time was 36-348 ms while total sinoatrial conduction time, determined in 4 patients, ranged between 83 and 128 ms. At our institution the Senning procedure has a low incidence of residual hemodynamic or electrophysiological abnormalities. Detailed postoperative evaluation is necessary to determine extent of residual problems.

Electrocardiography↗

Two-dimensional echocardiographic detection of pulmonary venous channel stenosis after Senning's operation.

Stenosis of the common pulmonary venous (PV) channel after Senning's operation for complete transposition of the great arteries is a serious problem, and a method for noninvasive diagnosis is highly desirable. Therefore, our purpose was to devise a method to diagnose PV channel stenosis noninvasively. The newly created common PV channels were measured and the short-axis views of the left ventricle were observed by means of two-dimensional echocardiography in 16 patients who had undergone Senning's procedure. In seven patients we used the original procedure and in nine patients we used a modified procedure with a pedicled pericardial patch. The shape of the left ventricle became round abruptly when the width of the PV channel decreased below a critical value (a range of 6 to 9 mm). Three patients with a relatively round-shaped left ventricle and a narrow PV channel (below 9 mm) were all confirmed to have PV channel stenosis at reoperation. All of the patients with a wide PV channel (above 10 mm) and a flat-shaped left ventricle were in good condition both clinically and as determined from the catheterization data. After the operation, patients who had tricuspid regurgitation, pulmonary vascular obstruction, or residual left ventricular outflow tract stenosis had a relatively round-shaped left ventricle even though the PV channel was wide enough (above 10 mm). Measurement of the PV channel confirmed the effects of these conditions. Correct diagnosis of PV channel stenosis can therefore be made by observing the shape of the left ventricle and by measuring the PV channel.

Child↗

Global and regional right ventricular function in normal infants and infants with transposition of the great arteries after Senning operation.

Echocardiographic assessment of right ventricular size, global function, and regional wall motion was performed in 29 normal infants and 19 infants with transposition of the great arteries 1 to 41 months after they underwent the Senning procedure. Sixteen of the patients with transposition of the great arteries were in clinically good condition and three had congestive heart failure. The right ventricular endocardial surface was digitized frame by frame for a complete cardiac cycle in both subxiphoid long-axis (coronal plane) and short-axis (parasagittal plane) views, and the cross-sectional area and the area change fraction (AF) were calculated. In each plane the right ventricular wall was subdivided into four anatomic regions (infundibular, free wall, diaphragmatic, and septal). With the use of a floating point center of mass model the direction and average extent of motion of the endocardium was determined for each region. In normal infants the infundibular and free wall portions of the right ventricle exhibited the greatest inward motion and the septal segments the least inward motion. Although the maximal area in both long-axis (r = .85) and short-axis (r = .85) views was highly correlated with body surface area (BSA), neither global nor regional function was significantly correlated with age or BSA. In clinically well patients after Senning procedure regional right ventricular function followed an entirely different pattern than that seen in normal infants. The endocardium of the septal segments showed the greatest inward motion in systole. In contrast to those in normal infants, maximal and minimal cross-sectional areas did not correlate significantly with BSA.(ABSTRACT TRUNCATED AT 250 WORDS)

Child, Preschool↗

Sensitometric response of the Sens-A-Ray, a charge-coupled imaging device, to changes in beam energy.

OBJECTIVES: To evaluate image density (pixel values) and image contrast due to variations in beam energy (kVp) for the Sens-A-Ray intra-oral radiographic sensor. METHOD: Images of an aluminium step wedge were made at 50, 70 and 90 kVp. Mean pixel values (with standard deviations) for representative attenuator thicknesses were measured using region-of-interest histogram analysis. Corresponding entrance doses were measured using a beryllium-windowed ionization chamber. RESULTS: The steepest response slopes were found with the lowest kVp settings; hence the CCD results mimic the behaviour of standard radiographic film, with the high contrast being found with low kVp. The entrance dose resulting in pixel saturation was less with low kVp than high kVp. It is suggested that this is due to the CCD receptor being most sensitive to X-ray photons of relatively low keV. CONCLUSION: While the kVp needs to be selected in relation to both tissue and receptor characteristics, it is possible to use low kVp techniques with the Sens-A-Ray without increasing the entrance dosage.

Electricity↗

Some results on extensions and modifications of the Theil-Sen regression estimator.

Many robust regression estimators have been proposed that have a high, finite-sample breakdown point, roughly meaning that a large proportion of points must be altered to drive the value of an estimator to infinity. But despite this, many of them can be inordinately influenced by two properly placed outliers. With one predictor, an estimator that appears to correct this problem to a fair degree, and simultaneously maintain good efficiency when standard assumptions are met, consists of checking for outliers using a projection-type method, removing any that are found, and applying the Theil-Sen estimator to the data that remain. When dealing with multiple predictors, there are two generalizations of the Theil-Sen estimator that might be used, but nothing is known about how their small-sample properties compare. Also, there are no results on testing the hypothesis of zero slopes, and there is no information about the effect on efficiency when outliers are removed. In terms of hypothesis testing, using the more obvious percentile bootstrap method in conjunction with a slight modification of Mahalanobis distance was found to avoid Type I error probabilities above the nominal level, but in some situations the actual Type I error probabilities can be substantially smaller than intended when the sample size is small. An alternative method is found to be more satisfactory.

Humans↗

Noncompaction of the right ventricle following Senning repair.

A three-year-old boy presented with generalized edema, respiratory distress, prominent right ventricular impulse and hepatosplenomegaly. He had undergone Senning repair at one year of age. On his echocardiography, there were numerous prominent trabeculations and deep intertrabecular recesses measuring approximately 5 mm in depth along the free wall and right ventricular apex. Echogenicity of the endocardial surface was increased suggesting a fibrotic process in progress. Intertrabecular recesses were observed to be filling from the ventricle by color Doppler which is consistent with noncompaction. Various semilunar valve obstructions were shown to be responsible for the persistence of deep endomyocardial spaces surrounded by exeggerated hypertrophy of the trabeculae. This report presents the echocardiographic findings of right ventricular cardiomyopathy associated with dextroposition of the great arteries following Senning operation resembling noncompaction. Thus, this rare entity needs to be clarified regarding morphological criteria in distinction from other cardiomyopathies.

Cardiomyopathies↗

Profulla Kumar Sen: his contributions to cardiovascular surgery.

One of the most eminent cardiothoracic surgeons of India, Profulla Kumar Sen (1915-1982) had a keen interest in research and in the subsequent clinical application of knowledge gained in the laboratory. His most significant contributions are his pioneering work on a transmyocardial acupuncture technique for treatment of ischemic myocardium, on heart transplantation in canine models and later in human beings, and on a new technique for aortic arch replacement. Transmyocardial laser revascularization of the 1990s was but an extension of his mechanical myocardial acupuncture for the treatment of ischemic heart disease, which he introduced 30 years earlier. On 16 February 1968, after many years of preparation through work with animal models, P.K. Sen and his team performed the 1st cardiac transplantation in India and the 6th in the world.

Acupuncture Therapy↗

Results of Senning operation for transposition of great arteries.

We report our results with 10 infants and children who underwent atrial repair using the Senning operation between 1985 and 1990. All cases had abdominal situs solitus, levocardia and atrio-ventricular concordance (D-bulboventricular loop). Nine patients had simple D-transposition of the great arteries without ventricular septal defects (VSD) or left ventricular outflow tract obstruction. The other patient had a double outlet right ventricle with subpulmonic VSD and pulmonary hypertension (PHT) and underwent a palliative Senning procedure. All patients had a balloon atrial septostomy (BAS) before surgery, except for one with Taussig-Bing syndrome. One patient had a Blalock-Hanlon operation after BAS. The age at the time of surgery ranged from two months to four years seven months (mean: 22 months) and weight ranged from 4.3-12 kg. There were two hospital mortalities including the patient with VSD and PHT. All of the patients had echocardiographic examinations and six of the eight survivors received cardiac recatheterization four to 19 months (mean: 7.4 months) postoperatively. No baffle leaks were noted in the survivors. Two patients had both mild tricuspid regurgitation and slightly decreased right ventricular contractility, and one patient had a pressure gradient of 6 mmHg between the superior vena cava and neo-right atrium. The clinical follow-up interval was eight to 64 months (mean: 31.4 months). All survivors showed a sinus rhythm on their latest electrocardiogram and were participating in normal daily activities without medication.

Child, Preschool↗