Volume 1 - Número 1

Keywords:

Unipolar pulse generators, either single or dual chamber, can be inhibited or reverted to the asynchronous mode, by skeletal muscle myopotentials. Dual chamber pacemakers may even stimulate the ventricle at the upper rate limit because of myopotential sensing via the atrial channel. A unipolar anti-tachycardia generator may be triggered by myopotentials to provoke an arrhythmia. During bipolar implanted pacing, episodic ventricular tachycardia has been induced in three patients with Chagasic cardiomyopathy and anodal stimulation has been shown to be the cause. Both unipolar and bipolar stimulation modes present problems. A stimulation mode with the cathode intracardiac and the anode remote from the generator and the patient's heart, called "tele-anode" was developed to be implanted in the presternal area or in venous system and avoid pacemaker triggering and inhibition. The subcutaneous "tele-anode" may be a spiral or a cylinder while an intravascular "tele-anode" may be positioned in the superior or inferior vena cava. Until March, 1986, 62 patients underwent "tele-anode" implantation, 57 at the sternum (51 spiral and 6 cylindrical) and 5 intramuscular. Thirty five generators were single chamber ventricular inhibited, 23 were dual chamber, 3 were atrial inhibited and 1 ventricular anti-tachycardia. In all cases the stimulation thresholds and electrogram characteristics were similar between intracardiac cathode and "tele-anode" and cathode and the puise generator site. Only electromyographic signals were consistently attenuated. One patient with an intravascular "tele-anode" died postoperatively of ventricular arrhythmias and one required ventricular lead repositioning. The 61 living patients, followed from one to twenty-one months, have shown no inhibition, triggering or noise mode reversion at nominal sensitivity setting. The authors conclude that pacemakers implanted with "tele-anode" show a clear evidence of decrease of associated complications, inherent to the conventional unipolar and bipolar cardiac stimulation system. Keywords: tele-anode; cardiac stimulation, techniques; pacemakers, cardiac

At the Instituto Dante Pazzanese de Cardiologia, a team project has been carried out since 1975, including obstetricians, pediatricians, cardiologists, anesthesiologists and cardiovascular surgeons aim at getting better results of cardiac surgery in pregnant women. For this purpose, the group developed a protocol that goes from the preoperative period to the delivery of the baby, with ecocardiographic and ultrasonic studies and fetal monitoring during the cardiac surgery of the mother. Twenty six patients were submited to cardiac surgery during pregnancy, and six patients after beginning the study, in 1985. The maternal and fetal results were good, without maternal death and the children were born without malformations and having had normal development until the sixth month of life. Keywords: cardiac surgery, pregnancy

A simple method is presented which proved to be effective for maintaining the heart and lungs viable and functioning in good hemodynamic and metabolic conditions outside of the body, for a period of up to 7 hours. After this, the heart-lung preparation is transplanted to another animal which maintains good parameters also for 3 hours. The hemodynamic, biochemical and histological features of this preparation are presented. In conclusion, preservation of a heart-lung allograft in a dynamic state provides a means to transport donor organs over long distances, and appears to be suitable to serve as a graft for heart or heart-lung transplantation. Keywords: heart-lung preparation; heart-lung preservation, experimental; heart transplantation

The authors analyse the results of 391 consecutive non-selected patients who underwent direct myocardial revascularization (MR) without cardiopulmonary bypass (CPB) from September 1981 to February 1985. In the same period we performed a total of 1568 revascularization procedures; thus 24.9% were MR without CPB. Out of the 391 patients, 318 (81.3%) were male and the ages varied from 35 to 76, with a median of 56 y/o. The surgical procedure was performed due to: chronic coronary insufficiency 286 (73.1%), after coronary thrombolysis 42 (10.7%), evolving acute myocardial infarction 18 (4.6%), ill-succeeded angioplasty 18 (4.6%), redos 14 (3.6%), intermediate syndrome 12 (3.1 %) and chronic aortic dissection 1. Single bypass was performed in 175 (44.7%) patients, double in 192 (49.1%) and triple in 24 (6.1%) with an average of 1.6 grafts/patient. The mammary artery was utilized 10Q times, bovine heterologous mammary 2 and all remaining cases received saphenous vein grafts. The hospital mortality was 2.5% (10/391) which is significantly different from our 5% hospital mortality in 1177 patients operated on the same period with CPB. We prospectively compared the postoperative complications in 378 patients without CPB against 689 patients with CPB concerning arrhythmias, perioperative myocardial infarction, neurologic, infectious, pulmonary and hemorrhagic complications. Keywords: myocardial revascularization, direct; extracorporeal circulation

The growth of atypical mycobacteria was observed in experimental studies in vitro of porcine aortic valve (aortic wall coupon) after tanning in glutaraldehyde solution at 0.625%. One hundred aortic wall coupons from different valves were incubated in 4 different culture media in a total of 400 cultures, employing the Thioglycollate, Brain-Heart-Infusion, liquid Sabouraud-Dextrose and Micosel, which did not become positive for 72 hours. The growth of atypical mycobacteria was recognized in 23% of the samples from the Thioglycollate and Sabouraud media after the 5th day utilizing appropriate subculturing techniques and special culture media. The atypical mycobacteria were identifyed as the Mycobacterium chelonei, which was demonstrated to be resistant to glutaraldehyde and it was completely eliminated by the formaldehyde in association with the surfactant. Keywords: heart valve prosthesis; endocarditis; mycobacteria, atypical

This is a report of 27 patients presenting annulo-aortic ectasia submitted to surgical correction with a composite valve-tube graft (Bentall-De Bono technique), between 1976 and 1985. Twenty three (85.2%) had cystic medial necrosis, 3 (11,1%) were chronic aortic disections and 1 (3.7%) was luetic aortitis. Age ranged from 29 to 64 years (m = 48). Three were female and 24 male patients. The valves used were homologous dura maier in 7 cases, heterologous aorta in 9 and mechanical prosthesis in 11. Functional class (NYHA) was I-II in 7 and III-IV in 9 patients. There was 1 (3.7%) hospital death, due to bleeding and renal failure. Significant early complications were represented by arrhythmias in 13 cases (48%) and bleeding in 3 (11%). In the late follow-up therev.were 9 deaths, due to: sudden death (2 patients, 7.4%), bleeding in reoperation (1 patient, 3.7%), hospital infection (1 patient, 3.7%), infectious endocarditis (1 patient, 3.7%) and accidental causes (2 patients, 7.4%). Five patients (18.5%) needed reoperation in the late follow-up: 2 due to bioprosthetic failure, 2 for replacement of an infected Dacron tube and 1 for repair of pseudo-aneurysm and periprosthetic leak. The actuarial survival curve showed a probability of 83.7% up to the 3rd. year, 61 % for the 5th. year and 42.7% from the 6th. to the 9th. year of follow-up. The 17 patients surviving are in functional class I-II (NYHA). The composite valve-Dacron tube graft (Bentall-De Bono) technique for correction of annulo-aortic ectasia is associated with a low hospital mortality. The improvement in functional class is significant. There have been a small number of complications and the long term survival is very satisfactory. Keywords: annulo-aortic ectasia, surgery

Evaluation of blood flow in saphenous vein grafts during coronary surgery gives valuable information about myocardial perfusion and long-term by- pass patency as well. However, electronic flowmeter availability is a limiting factor because of costs and maintenance. A system was developed consisting of a connection to the arterial line, with a Y tube; one branch of the Y tube is connected to a manometer and the other one to the vein graft. Since the connection to the arterial line has a know diameter, pressure drop in the system is proportional to the flow in the graft. With previous calibration, a chart was constructed that allows instantaneous evaluation of the flow. Another advantage of the system is the selective perfusion of the area to be treated before the conclusion of the proximal anastomosis. This system is being used in our Service; it is efficient and practical. Keywords: flowmeter, hidro-dynamic; myocardial revascularization