Mário O Vrandecic

Appraisal of " Mahaim" Automatic Tachycardia

“Mahaim” Automatic Tachycardia. A series of four patients with right‐sided accessory pathways with long conducting times and decremental properties is reported. All patients underwent radiofrequency catheter ablation, and target areas were guided by a discrete “Mahaim” potential recorded at the lateral aspect of the tricuspid valve. A slow automatic and irregular rhythm with a QRS morphology similar to that of a fully preexcited QRS complex occurred during radiofrequency current delivery. The occurrence of so‐called “Mahaim” automatic tachycardia heralded successful elimination of the accessory pathway in a manner similar to that of junctional automatic rhythm during slow pathway ablation in patients with AV nodal reentrant tachycardia. The observation of an automatic rhythm brought about during radiofrequency current ablation of a Mahaim‐like accessory pathway is electrophysiologic evidence of the accessory AV nodal behavior of this structure.

Stenless porcine and pericardial valve in aortic position

Fifty-seven patients underwent aortic valve replacement with a stentless glutaraldehyde-fixed bioprosthesis; 27 received a porcine aortic valve and 30 had a bovine pericardial valve. Two groups of 30 patients each who had aortic valve replacement with a tilting-disc mechanical valve or a stented porcine bioprosthesis served as controls. There were no differences in sex, body surface area, valve lesion, and valve size among the four groups. Results were assessed on a Doppler-based determination of maximum velocity across the valve, aortic valve area, and degree of valve regurgitation. Velocity across the valve was significantly less with stentless pericardial valves than with stentless porcine valves, stented bioprostheses, and mechanical valves. Stentless valves had a significantly larger aortic valve area when compared with stented valves. Mild central aortic insufficiency was detected more often with stentless pericardial than with stentless porcine bioprostheses (p = 0.04). Stentless valves showed a higher incidence of complete atrioventricular block when compared with stented valves (p = 0.04). Long-term studies are now warranted to assess the durability of both types of stentless valves.

Retrospective clinical analysis of stented vs. stentless porcine aortic bioprostheses

OBJECTIVE The study was designed to compare hemodynamic performance, structural failure and survival of patients undergoing aortic valve replacement (AVR) with a composite aortic stented or stentless porcine bioprosthesis. METHODS From January 1990 to June 1999, the clinical data of 725 patients undergoing AVR with stented porcine aortic bioprosthesis were reviewed. We defined two groups of patients with similar clinical characteristics: 202 patients receiving aortic stented and 205 patients stentless valves. The two patients groups were similar in age, sex, valve lesion, valve size, preoperative New York Heart Association (NYHA) class status and follow-up. RESULTS The number of patients available for follow-up, excluding hospital and late mortality, reoperations and patients lost to follow-up, was 157 for the stented and 175 for the stentless group. There was a higher incidence of rheumatic heart disease in the stented (59%) vs. stentless group (44%), (P=0.003). Fewer patients had prior aortic bioprosthetic dysfunction in the stented (7.6%) compared to the stentless group (25%) (P<0.001). The mean intensive care unit stay, hospital mortality and late mortality were similar (P, NS). The total complication rate was higher in the stented (12%) than the stentless (3.4%)(P=0.005). Valve related death was higher in the stented (2.5%) than the stentless (0%) (P=0. 049). Postoperatively, the aortic effective orifice area (AEOA) was larger (P<0.001) and the transvalvular peak and mean gradients were lower in the stentless group (P<0.001). The leaflet tissue degeneration analysis was 8.0% in patients at risk for stented and 0. 6% for stentless (P=0.001). Actuarial analysis disclosed no statistical difference in patient survival between groups (P=0.18). Reoperations were less frequent in the stentless group (P=0.010). CONCLUSIONS Hemodynamic benefits in the stentless group were evident and expressed by larger AEOA, lower gradients, better left ventricular remodeling with significant decrease of the left ventricular mass. Lower complication rates, lower reoperation rates, less leaflet tissue degeneration, and lower valve related mortality rates were seen in the stentless group. A controlled clinical comparison trial with longer follow-up will be required to confirm these clinical and hemodynamic benefits.

Fontan operation: a technique in evolution.

OBJECTIVES Recent experimental flow studies based on angiography and magnetic resonance have shown that total cavopulmonary anastomosis (TCPA) is a valid concept for surgical treatment of many congenital heart defects, but there is not agreement of the best surgical arrangement. Our purpose is to analyze the immediate results with three different techniques of TCPA. METHODS We sought to analyze retrospectively all TCPA realized from January 2005 to July 2008; there were 40 patients, all with previous Glenn anastomosis, with mean age of 6.4 +/- 3.2 years. Three different techniques were employed: Group 1 (G1) lateral tunnel, Group 2 (G2) extracardiac conduits, Group 3 (G3) intracardiac conduit directed to the left pulmonary artery. All patients had a fenestration done. RESULTS G1 had 11 patients, G2 10 patients and G3 19 patients. Preoperative data were similar in the 3 groups (P>0.05). Surgical mortality was higher in Groups 1 and 2 (9.1% and 10%) compared to Group 3 (0%) but there was no statistical significance (P=0.3841). Pleural effusion was absent in Group 3 (0%), which was statistically significant in relation to the other groups (P=0.0128). The hospitalization time was also significantly lower in G3 (8 days) in relation to G1 (18 days) and G2 (13 days) (P=0.0164). CONCLUSION Intracardiac TCPA was associated with lower postoperative morbidity and is currently our preferred technique.

Radiofrequency catheter ablation of an accessory pathway in a patient with Wolff-Parkinson-White and Kartagener's syndrome.

We report a case of a manifest left free wall accessory pathway in a patient with Kartageners syndrome and recurrent episodes of orthodromic atrioventricular reentrant tachycardia. To the best of our knowledge, it is the first report of Wolff‐Parkinson‐White syndrome associated with Kartageners syndrome. Situs inversus and mirror image dextrocardia occurred with no additional detectable cardiac structural abnormalities. Diagnostic and therapeutic electrophysiological study was carried out via transaortic approach and a left‐to‐right reversal of monoplane fluoroscopic image. (PACE 2004; 27:401–404)

Porcine stentless valve/bovine pericardial conduit for right ventricle to pulmonary artery

BACKGROUND AND OBJECTIVES We assessed the long-term outcome of a glutaraldehyde-preserved bovine pericardial conduit containing a stentless composite porcine aortic valve. METHODS Between November 1985 and May 1995, 33 stentless porcine valves attached to bovine pericardial conduits were used in 33 patients with complex congenital cardiac malformations. These patients required a conduit between the right ventricle and the pulmonary artery because of an absent or inadequate pulmonic artery. All patients were approached by midsternotomy. One patient with pulmonic atresia and an interventricular septal defect required left thoracotomy for ligation of collaterals. RESULTS Of the initial 33 patients, clinical follow-up was performed in 23 discharged patients (70%) for 1.7 to 10.5 years. The echo-Doppler analysis performed in each of the 23 followed patients showed excellent conduit and valve function in all but 4 patients, in whom a valve gradient of 60 mm Hg was noted. There was no tissue structural failure noticed in this study. CONCLUSIONS The SJM Biocor (Belo Horizonte, Brazil) bovine pericardial stentless valved conduit performed well as a substitute for the right ventricle to pulmonary artery connection.

Surgical technique of implanting the stentless porcine mitral valve

The new stentless porcine mitral valve was developed to serve as an anatomically correct substitute for a diseased mitral valve. Extensive acute animal experimentation was performed, and from this the logical sequence for selecting the correct valve size and the specific technique for implanting it were determined. The following are the major steps to successfully implant a mitral stentless valve: First, mitral valve complex analysis must be done to determine the correct procedure to be performed and the feasibility of using the stentless mitral valve. Second, the correct size of stentless mitral valve must be chosen. Third, the papillary muscle anatomy must be assessed to determine the site and number of sutures necessary for securely holding the new origin of the new chordae. Fourth, the papillary muscle sutures must be anchored to the free pericardial edge of the new chordal origin. Fifth, the chordal alignment with both trigonal areas must be perfect. Sixth, the annulus may be sutured using either continuous or interrupted sutures. Perioperative echocardiography, preferably transesophageal echocardiography, should be done in every patient. Although reoperation was necessary in 5 patients (non-valve-related), the results in 74 patients (3 early and 3 late non-valve-related deaths excluded) followed up for at most 26 months (mean, 14 months) have been excellent. The quality of the results obtained in this initial clinical trial has reinforced our current preference for this valve in patients requiring mitral valve replacement. Longer follow-up is required to confirm that these good results continue.

Modified Norwood procedure for hypoplastic left heart syndrome

OBJETIVO: Apresentar os resultados do tratamento da sindrome de hipoplasia do coracao esquerdo (SHCE) com tecnica de Norwood modificada, na qual somente sao usados tecidos autologos para a reconstrucao do arco aortico. METODO: De janeiro a dezembro de 2002, cinco recem-nascidos com idade variando de dois a nove dias (media 5,0 dias) foram submetidos a operacao de Norwood modificada. O diâmetro da aorta ascendente variou de 5 a 8 mm (media 6,2 mm). Foi empregada tecnica na qual o arco aortico e seus ramos foram amplamente dissecados, permitindo a reconstrucao de um novo arco aortico tendo a arteria pulmonar como via de saida, e com a utilizacao exclusiva de tecidos do proprio paciente. Anastomose sistemico-pulmonar com politetrafluoretileno expandido de 3,0 mm foi utilizada em tres pacientes e de 3,5 mm em dois pacientes. Todos foram operados com parada cardiocirculatoria total. RESULTADOS: O tempo de parada cardiocirculatoria variou de 41 a 60 minutos (media 52,8 minutos). Todas as criancas sobreviveram ao ato operatorio e foram encaminhadas para a unidade de terapia intensiva com o esterno aberto. Ocorreu um obito no 9: dia de pos-operatorio por sepse, o que resultou numa taxa de sobrevivencia imediata de 80%. Ocorreu um obito tardio por pneumonia de aspiracao aos dois meses. Uma crianca foi submetida ao segundo estagio da operacao (cavo pulmonar) e encontra-se bem. Duas criancas estao em acompanhamento aguardando o proximo estagio. Em nenhuma delas existem evidencias de obstrucao do novo arco aortico. CONCLUSAO: A tecnica de Norwood modificada mostrou-se eficaz e com risco cirurgico aceitavel para o tratamento da SHCE, sem evidencias de obstrucao do arco aortico reconstruido.

Reconstrução da artéria pulmonar na operação de Jatene

INTRODUCTION: We describe our experience with Jatenes operation in the surgical treatment of transposition of great arteries (TGA) where pulmonary artery reconstruction was performed with two autologous pericardial patches in order to spare the maximum amount of native aortic tissue. MATERIAL AND METHODS: There were 52 children (38 simple TGA, 14 TGA + VSD) and their age ranged from 3 days to 17 months. Body weight ranged from 2.400 to 7.400 kg (m=3.377 kg). All patients were operated under moderate hypothermia with a single infusion of blood cardioplegia. Average extracorporeal circulation time was 110.6 min and average aortic cross-clamping time was 72.5 min. RESULTS: There were 3 (5.8%) early deaths caused by pulmonary infection in 2 of them and by obstruction of the endotracheal tube in 1. There were 2 late deaths; one in a reoperation of severe coronary ostial stenosis (6 months p.o.) and another owing to pneumonia (1 year p.o.). Late echocardiography was performed in 20 children who were operated in the neonatal period and had a minimum of 5 months follow-up (m=12.7). Supravalvular pulmonary stenosis was found in only 1 (5%) patient and results were consistent with an uniform pulmonary artery development. CONCLUSION: Reconstruction of the pulmonary artery in Jatenes operation for TGA should be carried out with maximal preservation of the native aortic tissue.

Porcine mitral stentless valve mid-term clinical results.

OBJECTIVES Time testing is essential with any valvular procedure, especially when a new concept is introduced such as the mitral stentless valve. Our purpose is to evaluate the results obtained over 4 years with this operation, particularly to attest the impact of preservation of annulo ventricular continuity on the long term results of these patients. METHODS From March 1992 to August 1996, 120 patients had their mitral valves replaced with a porcine stentless mitral valve. The observation period was 54 months with total patients follow-up of 3424 months with a mean of 28.5 months. The age ranged from 11 to 72 years (mean 35.22 +/- 14.98). There were 73 females (60.8%) and 47 males (39.2%). The predominant etiology was rheumatic heart disease. Associated procedures were performed in 12 patients (10%), and the great majority of the patients were in functional class III and IV (NYHA). RESULTS Hospital mortality occurred in seven patients (5.83%) non valve related except for one early case of endocarditis. Early reoperation related to technical failure were necessary in 4 patients without mortality. Follow-up was accomplished in 101 patients and ranged from 2 to 54 months. Late reoperations were required in 16 patients (nine due to mitral insufficiency, five because of endocarditis and two for mitral stenosis). Most reoperations were related to technical failure. Among the 82 patients presently in control, 72 showed a competent mitral stentless valve, eight with stable mild mitral regurgitation and in two a decreased mitral orifice. Hemodynamic performance of the valve has been excellent in this group, particularly in patients with left ventricular dysfunction. CONCLUSION Although technical complexity remains the main cause of reoperations with this valve, experience has shown that it not only provides preservation of the left ventricular function but also promised significant increase of the ejection fraction in patients with poor left ventricular function.