Volume 9 - Número 3

Epicardial fetal pacing via thoracotomy has the potential for being a safer and more reliable procedure to treat congenital complete heart block (CHB) associated with fetal hydrops refractory to medical therapy. To assess the acute electrophysiologic characteristics of two ventricular epicardial leads, a new experimental model of fetal heart block induced by cryosurgical ablation of the AV node without the need for fetal cardiac bypass was performed in 12 pregnant ewes at 110-115 days of gestation. A modified screw-in lead (one and a half turn) was used in 6 fetal lambs and a stitch-on lead in the other 6 lambs. CHB was achieved in 100% of the fetal lambs, with no ventricular escape rate noticed in any of the lambs. The acute stimulation thresholds were consistently low for both the leads, with lower values for the screw-in lead at pulse duration below 0.9 ms (p < 0.03). Current measured at voltage threshold with pulse width below 0.5 ms was lower for the screw-in lead (p < 0.048). Stimulation resistance, measured during constant-voltage pacing, was not statistically different between the two leads (441.8 ± 13.7 O for the screw-in lead versus 480.2 ± 59.2 O for the stitch-on lead). No significant differences (p > 0.20) were found in R-wave amplitude between the two electrodes. Slew rates were significantly higher with the screw-in group than with the stitch-on group (1.40 ± 0.2 versus 0.62 ± 0.2 V/s, p=0.04). This model of CHB is a simple and reproducible method to assess fetal pacing. We find the screw-in electrode a better option when fetal pacing is indicated. Keywords: fetal cardiology; fetal heart block; fetal surgery; fetal arrhythmias; fetal pacing

BACKGROUND: Epimyocardial pacemaker leads has been progressively given-up due to poorer results in comparison to endocardial pacing. Transthoracic transatrial endocardial lead placement has been described to avoid epicardial pacing in special situations. Permanent pacing associated to open heart surgery is a special situation when epicardial leads have been implanted at the same procedure or endocardial leads have been inserted with an independent approach. OBJECTIVE: To propose transatrial endocardial pacemaker in cases of concomitance of permanent pacing and open heart surgery and to report our experience with this technique in 6 patients. MATERIAL AND METHODS: From July 83 to August 94, 6 patients, 5 to 64 years old, 4 male and 2 female, were submitted to open heart surgery for aortic valve replacement (4), Chaga's disease left ventricular aneurysm resection (1) and atrioseptoplasty and pulmonary valve comissurotomy (1 patient). At the same procedure, atrioventricular (5) or atrial (1 case) pacemaker were implanted. The surgical technique consisted in stablishing cardiopulmonary bypass with two separated vena cava canulas and, under cardioplegic arrest, to correct the cardiac defect and to implant the leads through a rigth atriotomy, at the same procedure. AH the 6 patiens received atrial endocardial lead while only 4 patients were submitted to ventricular endocardial implantation. The pulse generators were implanted in the infra-clavicular region in the 4 male adults, in the submammary position in the woman and in the abdominal wall in the child. RESULTS: Intra-operative measurements showed excellent conditions for pacing and sensing. No peroperative complication occurred. After a 4 to 137 months follow-up period no complications related to the pacemaker were observed. CONCLUSIONS: The authors conclude that transatrial endocardial pacemaker implantation may represent a good option to avoid epicardial leads or two independent procedures when permanent pacing is associated to open heart surgery. Keywords: pacemakers, cardiac, surgery; cardiac stimulation, artificial, pacemakers

OBJECTIVE: To present a number of modifications to the conventional heart implant technique in orthotopic cardiac transplants. METHODS: The proposed modifications consist basically of the following: 1) resecting as much of the disease heart as possible during the cardiectomy, leaving only sufficient tissue to enable the new heart to be sutured during the implant; 2) opening the right atrium of the donor heart from the inferior vena cava, close and parallel to the interatrial septum as far as the highest part, where the incision should be sharply directed towards the right atrial apendix; 3) initiating the implant through the pulmonary artery, and 4) suturing the atria simultaneously, in a single plane, atthe level of the septum. These technical modifications have been utilized in all patients undergoing transplants in the three Institutions. REMARKS: The technical changes present the following advantages: 1) a perfect alignment of the pulmonary artery, thereby avoiding bending and torsion and 2) smaller atrial cavities with no sutures protouding into the atria and, consequently, less likelihood of tromboembolic phenomenon or asynchronous contractions of the atria (donor-receiver) which, in addition to facilitating the formation of thrombi, may impair the functioning of the atrioventricular valves. CONCLUSIONS: The method is easily reproducible and can be recommended for orthotopic heart transplants. Keywords: heart transplantation, orthotopic

The surgical approach to coronary artery disease has improved a lot during the past two decades. With the widespread use of balloon angioplasty, a growing percentage of surgical patients, have complex coronary pathology. In properly selected patients, coronary endarterectomy has been a valuable adjunt to bypass techiniques by removing obstructing lesions and preparing the distal artery for bypass grafting. Over a 5 years period (1988 to 1993), 2781 patients underwent surgical revascularization at our Instituition (Hospital do Coração). Coronary artery bypass combined with coronary endarterectomy was done in 110 patients. There were 99 men (90%) and 11 women, mean age 58.9 years. For comparation patients were placed into two groups: Group A, patients undergoing endarterectomy to one artery, 104 patients - 94.5%. Group B, patients with more than one endarterectomy - 6 patients 5.4%. Perioperative myocardial infarction envolving the area supplied by the endarterectomized artery occurred in 6.3%, (7 patients). In 3 (2.7%) the infarction was not related with the endarterectomized artery. Complications during the post-operative period were: arrhythmia in 26 patients (23.6%), return to the operation room for control of bleeding in 12 (10.9%), acute renal failure in 10 (9%), and low cardiac output in 4 (3.6%) patients. Operative mortality rate was 4.5% (5/110), due to low cardiac output and multiple organs failure; 4 (3.8%) patients belonged to Group A and 1 to Group B (16.6%). This study demostrates that multiple bypass grafting and adjunt coronary endarterectomy, can yeld good clinical results in patients with difuse coronary artery disease, many of whom would otherwise be inoperable. Keywords: coronary artery, revascularization, surgery

This second part will cover operative technique, postoperative approach and reoperations of valvopathy patients. In Operative Technique, there is the description of the anesthesia procedures, surgical approach which includes the assembling of the extracorporeal circulation and surgeries of mitral, aortic, tricuspid and pulmonary valves. In the Postoperative Approach, the routine in the Intensive Care Unity is reported, and in Reoperations the surgical technique is covered. Keywords: heart valves, surgery; valvopathies, operative techniques; valvopathies, postoperative approach; valvopathies, reoperation; heart valves prostheses

All patients aged > 80 years which underwent myocardial revascularization at the InCor Institute were analized in order to establish the evolution of surgical treatment of coronary artery disease. From the total of 79 patients, 60 (75.94%) were male and 19 (24.05%) female. The mean age was 82.33 (80 to 90) years. The symptons presented to indicate surgery was unstable angina in 56 (70.88%), stable angina in 22 (27.84%) and 1 (1.26%) patient was operated on after angioplasty. The autogenous saphena vein was the surgical approach in 69 (87.34%) patients while in 10 (12.5%) was the mammary vein. The present total nosocomial mortality rate reaches 6.32%. It has been decreasing at the Institution from 13.33% in 1990 it came down to 8.5% in 1993 presently it reaches 6.32%. Nosocomial causes of death were found to be anoxic encephalopathy, respiratory insufficiency, digestive hemorrhage and cardiogenic shock. Mean time follow-up ranged 18.3 (4 to 83) months. The determinant mortality time was infection, neoplasia, stroke, mesenteric thrombus, depressive syndrome and cardiogenic shock. Considering that: 1) The brazilian population has been getting older with the expectancy of life augmented; 2) The nosocomial mortality for myocardial revascularization in the elderly has been decreasing it is therefore concluded that the surgical treatment represents a good alternative for the octogenarian as it leads to a better quality and expectancy of life. Keywords: myocardial revascularization, surgery, elderly patients