Radiofrequency lesions produced by handheld temperature controlled probes for use in atrial fibrillation surgery.

OBJECTIVES: Detailed analysis of the size and shape of lesions produced by handheld radiofrequency ablation devices at open heart surgery has not been reported previously. METHODS: Radiofrequency lesions were made from the epicardial surface of the cardiac ventricles in open-chested dogs. The effects of electrode size, electrode temperature and duration of ablation were studied. In a second group of experiments simultaneous multielectrode ablation was performed on the ventricular epicardium after cold cardioplegia. RESULTS: Using a single 12 x 2.5 mm electrode and a target temperature of 80 degrees C the lesion depth increased from 3.8+/-0.9 mm at 15 s, to 6.1+/-0.9 mm at 120 s (P=0.01). Increasing the target temperature from 70 to 90 degrees C (for 60 s) increased lesion depth from 5.0+/-1.2 to 5.6+/-1.7 mm (P=0.2). There was no difference in depth of lesions with the two electrode widths (4.0+/-0.5 mm (large) vs. 3.9+/-1.0 mm (small)). Lesions produced using the multielectrode probe (80 degrees C, 60 s) were 30-35 mm long with even penetration into the tissue. The mean depth of these lesions on microscopic sections was 3.9 mm. The mean width was 7.1 mm. CONCLUSIONS: Handheld probes can be used to make deep linear lesions in the myocardium. Lesions expand rapidly and are wider than they are deep. A multielectrode ablation device allows rapid formation of linear lesions.

Minimal sternotomy approach for congenital heart operations.

BACKGROUND: In recent years, minimal access cardiac operations have increased in application in both the adult and pediatric population. As our experience has grown with these approaches to atrial septal defect closure, we have expanded the same approach to the repair of more complex congenital heart disease. METHODS: At the Children's Hospital in Boston, from August 1996 to November 1999, a minimal sternotomy approach was used to surgically correct 104 children with congenital heart defects other than atrial septal defect. The approach, in most patients, consisted of a skin incision based over the xiphisternum, 3.5 to 5 cm in length, with division of the xiphoid only and elevation of the sternum by fixed retractor. All patients underwent cannulation for cardiopulmonary bypass through the great vessels in the chest using this same incision. The lesions corrected included ventricular septal defect in 41 patients, tetralogy of Fallot in 27, common atrioventricular canal in 15, mitral valve operation in 3.5, and other defects in 18 patients. There were 53 male and 51 female patients. Mean age at operation was 1.4 years (range, 2 weeks to 11 years). RESULTS: There were no deaths. The mean cardiopulmonary bypass time was 71 minutes (standard deviation, 19 minutes), mean cross-clamp times 40.8 minutes (standard deviation, 13 minutes), and length of stay 4.5 days (standard deviation, 1.9 days). Complications included transient atrioventricular block in 2 patients, pleural effusion requiring drainage in 4, and pericardial effusion in 3 patients. When compared to similar lesions repaired using a full sternotomy approach there was no difference in operating times and length of stay tended to be shorter in the minimal sternotomy group. CONCLUSIONS: A minimal sternotomy approach can be used to repair congenital cardiac lesions other than atrial septal defects. It gives good exposure, particularly for transatrial repairs, does not prolong ischemic times, and may lead to shorter hospital stay.

"A coherent datum of perception": Gordon Allport, Floyd Allport, and the politics of "personality".

This paper examines Floyd and Gordon Allport's early work on "personality" psychology. In the early 1920s, personality was an unorthodox topic, and for the Allports it initially served as an intellectual and personal bond. Floyd proposed the subject to his brother as a dissertation topic, and the two worked closely on developing personality tests. By 1924, however, "personality" had become the site of a dispute between the two brothers over the intellectual and methodological character of American psychology. The present study examines the origins of this dispute, while gauging the personal and professional ramifications of the dispute. On a larger level, this essay explores the role and meaning of "personality" in the academic culture of 1920s America.

Surgical management of complex and tunnel-like subaortic stenosis.

BACKGROUND: Relief of primary or secondary subaortic stenosis (SAS) remains a surgical challenge. Heart block, aortic valve regurgitation and recurrent obstruction have been persistent problems. METHODS: Forty six patients who underwent surgery for complex and tunnel-like SAS between January 1990 and November 1998 were reviewed. In 45 of the 46 patients SAS developed following repair of a primary congenital heart defect and only one patient presented with de novo tunnel-like SAS. Fifteen of the 45 patients had undergone repair of double-outlet right ventricle (DORV) and the remaining 30 had undergone repair of a variety of defects. The median age at the time of surgery was 5 years. The modified Konno procedure was performed in 15 patients, Konno procedure in three, Ross-Konno procedure in two and resection of the conal septum in 12 patients. Five patients with DORV underwent replacement of the intraventricular baffle and two patients underwent an aortic valve-preserving procedure in conjunction with mitral valve replacement. RESULTS: There were no deaths. None of the patients had an exacerbation of aortic regurgitation and none developed complete heart block. The median follow-up was 3 years (range 1 month-8.5 years). Two patients developed recurrent SAS defined as a gradient of 40 mmHg or greater diagnosed by transthoracic echocardiography. Freedom from SAS at 1, 3 and 5 years was 100, 94 and 86%, respectively. CONCLUSIONS: We favor the modified Konno procedure and conal resection to the Konno or the Ross procedure, since insertion of a prosthetic valve or homograft is avoided and aortic valve function is preserved. Excellent relief of tunnel-like SAS can be achieved without damage to the conduction tissue.

Effect of atrial radiofrequency ablation designed to cure atrial fibrillation on atrial mechanical function.

INTRODUCTION: The effects of linear radiofrequency lesions in the atria for cure of atrial fibrillation on atrial contraction have not previously been quantified. METHODS AND RESULTS: Atrial function was measured before and 30 +/- 24 days after a biatrial ablation procedure designed to cure atrial fibrillation in eight dogs and after a sham procedure in three dogs. Atrial mechanical function was assessed using Doppler diastolic blood flow velocities, atrial systolic pressure wave amplitude, and assessment of atrial contribution to cardiac output estimated by comparison of AV sequential pacing to ventricular pacing at the same heart rate. The mitral Doppler A/E velocity ratio was 1.03 +/- 0.45 before and 0.72 +/- 0.43 after ablation (P = 0.048). The tricuspid A/E ratio was 0.88 +/- 0.17 before and 0.71 +/- 0.12 after ablation (P = 0.04). The estimated atrial contribution to cardiac output was 18% +/- 9% before and 5% +/- 4% after ablation (P < 0.01). The left atrial systolic pressure wave amplitude was 2.8 +/- 1.5 mmHg before and 1.7 +/- 1.0 mmHg after ablation (P = 0.1). These changes were not observed in control dogs. Lesions covered 25% +/- 6% of the atrial endocardial surface. CONCLUSION: Multiple linear radiofrequency lesions in the atria designed to cure atrial fibrillation may impair atrial contractility. Reduced atrial function is partly due to loss of atrial myocardial mass, but regional delays in atrial activation and splinting of the atria by scarring also may contribute.

Transcaval repair of the sinus venosus syndrome.

BACKGROUND: Surgical correction of the sinus venosus syndrome has been associated with sinus node dysfunction and venous obstruction postoperatively. We present the long-term follow-up of a lateral transcaval approach, which closes the atrial communication and corrects the partial anomalous pulmonary venous connection to the superior vena cava with the use of a simple pericardial patch. METHODS: The records of 66 patients undergoing repair between April 1981 and April 1997 were examined. Mean age at repair was 10.2 years (range, 1.5-65 years; median, 5 years). Six patients had a left superior vena cava, 4 had an additional atrial septal defect, and 2 had coronary artery bypass grafts. Immediate and long-term follow-up included physical examination, electrocardiography, transthoracic echocardiography, and use of a 24-hour ambulatory Holter monitor. Sinus node function, incidence of significant arrhythmia, and evidence of mechanical venous obstruction were assessed. RESULTS: Follow-up data were available for 64 (97%) patients for a mean follow-up of 4.1 years (range, 1-9 years). There were no deaths. No evidence of residual atrial septal defect, superior vena cava, or venous obstruction were found by echocardiography. On electrocardiography all patients were in sinus rhythm, with no arrhythmia seen. Holter monitoring was performed at a mean of 7.3 years postoperatively. All patients had normal sinus node function, and no sustained atrial arrhythmia was seen. CONCLUSION: Transcaval repair is a simple technique that does not interfere with sinus node function. There is no evidence to suggest that this approach leads to venous obstruction.

Mechanism, localization and cure of atrial arrhythmias occurring after a new intraoperative endocardial radiofrequency ablation procedure for atrial fibrillation.

OBJECTIVES: The purpose of this study was to test a new pattern of radiofrequency ablation for atrial fibrillation (AFib) intended to optimize atrial activation, and to demonstrate the usefulness of catheter techniques for mapping and ablation of postoperative atrial arrhythmias. BACKGROUND: Linear radiofrequency lesions have been used to cure AFib, but the optimal pattern of lesions is unknown and postoperative tachyarrhythmias are common. METHODS: A radial pattern of linear radiofrequency lesions (Star) was made using an endocardial open surgical approach in 25 patients. Postoperative arrhythmias were induced and characterized during electrophysiological studies in 15 patients. RESULTS: The AFib was abolished in most patients (91%), but atrial flutter (AFlut) occurred in 96% of patients postoperatively. At postoperative electrophysiological studies, 37 flutter morphologies were studied in 15 patients (46% spontaneous, cycle length [CL] 223 +/- 25 ms). Seven mechanisms (lesions discontinuity, n = 6; focal mechanism, n = 1) of AFlut were characterized in six patients. In these cases, flutter was abolished using further catheter radiofrequency ablation. In the remaining cases, flutter was usually localized to an area involving the interatrial septum, but no critical isthmus was identified for ablation. After 16 +/-10 months, 15 patients (65%) were asymptomatic with (n = 3) or without (n = 12) antiarrhythmic medications. Eight (35%) patients had persistent arrhythmias. Postoperative atrial electrical activation was near physiological. CONCLUSIONS: The AFib maybe abolished using a radial pattern of linear endocardial radiofrequency lesions, but postoperative AFlut is common even when lesions are made under optimal conditions. Endocardial mapping techniques can be used to characterize the flutter mechanisms, thus enabling subsequent successful catheter ablation.

Simplified single patch technique for the repair of atrioventricular septal defect.

OBJECTIVE: Because of the complexity of traditional 1- and 2-patch techniques for the repair of complete atrioventricular septal defect, we modified our repair technique to avoid the use of any ventricular septal patch material. We report our prospective experience with this simplified 1-patch technique. METHOD: Forty-seven consecutive patients between May 1995 and August 1998 underwent repair with the use of this technique without modification. Repair was done in all patients by direct suturing of the common atrioventricular valve leaflets to the crest of the ventricular septum. No division of valve leaflets was necessary. A single pericardial patch was used to close the defect in the atrial septal component. Follow-up included electrocardiography and echocardiographic assessment of ventricular function, atrioventricular valve function, and adequacy of the left ventricular outflow tract. RESULTS: There were 2 deaths (4%), only 1 cardiac related, in the series. There were 17 male patients and 30 female patients. Mean age at repair was 5.6 months (median, 3.4 months). Associated lesions were repaired in 19 patients (40%). Mean follow-up was 1.85 years (median, 1.9 years). There was no heart block. There were no significant residual ventricular septal defects detected and no left ventricular outflow tract obstruction seen on echocardiography in any patient to date. Mitral valve status after operation was assessed as no incompetence in 13 patients (28%), minimal in 19 patients (40%), mild in 12 patients (26%), and moderate in 3 patients (6%). CONCLUSION: The repair of complete atrioventricular septal defect by direct suturing of the atrioventricular valve leaflets to the crest of the ventricular septum with a single-patch technique greatly simplifies the repair and does not lead to left ventricular outflow tract obstruction nor interfere with valve function.

Neonatal ductus arteriosus aneurysm causing nerve palsies and airway compression: surgical treatment by decompression without excision.

A 4-kg male child, born at 34 weeks to a gestational diabetic mother, had a large ductus arteriosus aneurysm causing phrenic and recurrent laryngeal nerve palsies and large airway compression. The right and left atrial appendages and distal descending aorta were cannulated, allowing left heart partial or complete cardiopulmonary bypass as necessary. On bypass the ductus was ligated, decompressed, and oversewn but not excised. Examination 1 month later suggested resolution of the recurrent laryngeal palsy and echocardiography showed regression of the aneurysm. Ductus ligation and decompression was an effective surgical treatment, which is less likely to cause complications than resection.

Laparoscopically assisted massive splenectomy. A preliminary report of the technique of early hilar devascularization.

Laparoscopic splenectomy has been safely performed for small spleens, but technical limitations have prevented massive splenectomy. We describe a technique of early hilar devascularization to enable massive splenectomy in three patients over the age of 80 years. Massive splenectomy was performed with minimal blood loss and minor morbidity. Early laparoscopic control of the splenic artery and vein will enable the safe removal of the massive spleen, without major laparotomy. Morbidity of splenectomy may be reduced by laparoscopy.

Modified T graft for triple-vessel disease.

BACKGROUND: Arterial coronary bypass grafts are used in younger patients due to the limited long-term patency of saphenous vein grafts. Using both internal thoracic arteries in a T graft configuration allows complete myocardial revascularization without the need for alternative conduit. METHODS: A prospective analysis of 75 consecutive patients with triple-vessel disease who were aged less than 66 years and who had a left ventricular ejection fraction greater than 0.50 was performed from November 1994 to November 1995. Seventy-three patients underwent myocardial revascularization using a modified T graft technique using both internal thoracic arteries. Postoperative cardiac enzyme and electrocardiographic analyses were performed along with routine surgical and cardiologic review to March 1996. RESULTS: There were no deaths or perioperative myocardial infarcts, and there was no sternal dehiscence due to infection. Five patients had recurrent angina and underwent repeat angiography. Three were treated by single coronary artery angioplasty and 2 with medical therapy. CONCLUSIONS: A modified T graft revascularization of patients selected by the protocol used in this study is safe.

Effects of air filtration at small SO2 and NO2 concentrations on the yield of barley.

Two cultivars of Igri and Gerbel winter barley Horteum vulgare L. were grown in open-top chambers in filtered and unfiltered air at a site with approximately 10 nl litre(-1) SO2 and 12 nl litre(-1) NO2 (seasonal mean). The experiment ran for three consecutive seasons 1982-1983, 1983-1984, 1984-1985, and significant effects of filtration were observed for each crop. In years 1982-1983 and 1984-1985, the crops in unfiltered air yielded larger grain dry matter, 9% in 1982-1983, and 8% in 1984-1985. For both crops, the differences were statistically significant at the 5% level. Differences were also observed for the remaining above-ground dry matter, and these were consistent in direction in each year but statistically significant only in 1984-1985. In both growing seasons (1982-1983 and 1984-1985), there were no major pest infestations and no long-term water stress or photochemical ozone episodes. In the remaining experiment (1983-1984) similar air concentrations of SO2 and NO2 produced effects of the opposite sign to those observed in 1982-1983 and 1984-1985. Significant reductions in grain yield (13%) were obtained in unfiltered air. The only major environmental difference for the 1983-1984 crop was a notable dry period in May and June 1984 with marked water stress in the crop, requiring irrigation. These results suggest that the relationship between yield and pollutant concentration may be confounded by additional stresses, many of which are a common component of the growing season for major crops.