[Congenital mitral stenosis. Experience in 1991-2001]. / Estenosis mitral congénita. Experiencia 1991-2001.

OBJECTIVE: To describe ten years of experience with congenital mitral stenosis. METHOD: All cases with congenital mitral stenosis from January 1991 to 2001 were analized. RESULTS: 16 patients with congenital mitral stenosis were found, mean age 3 +/- 3.08 years. TYPES OF OBSTRUCTIONS: Mitral commisures combined with tendinous cords fusion (45%), parachute mitral valve 37%, supravalvar mitral ring in one, fusion between papillary muscle and leaflets in one, and double mitral orifice in one. Hemodynamic (in mmHg) findings: wedge pressure 18.4 +/- 4, pulmonary artery systolic 61 +/- 21, diastolic 34 +/- 15, mean 47 +/- 18 mmHg, mean transvalvar gradient (MTG) 12.9 +/- 7.3, PRU 5.5 +/- 3.8. Four patients received medical treatment. Surgical results: Six patients underwent mitral repair, and four were subjected to mitral valve replacement (two with previous mitral repair). Global mortality was 2 (12.5%). Follow-up was 3.5 +/- 3 years. There was a significant difference when the initial MTG 22.6 +/- 11.5 mmHg before surgical repair was compared with the final MTG 4.75 +/- 1.5 (P < 0.05), also when initial MTG 12 +/- 2.3 before mitral valve replacement was compared with the final MTG 6 +/- 1.15 mmHg (P < 0.05). CONCLUSION: Most patients are candidates for mitral surgical repair, however at mid term one third will require mitral valve replacement.

Clinical impact of histidine-ketoglutarate-tryptophan (HTK) cardioplegic solution on the perioperative period in open heart surgery patients.

BACKGROUND: Ischemia-reperfusion injury during open heart surgery related to unsuccessful myocardial protection may increase morbidity or mortality. We analyze the clinical outcome after cardiac surgery with a cardioplegic solution based on intracellular components added with histidine-ketoglutarate-tryptophan. METHODS: Thirty patients programmed for elective open heart surgery were randomized into two groups. In group I (n = 15), myocardial protection was carried out with Bretschenider solution (HTK), and in group II (n = 15) with conventional crystalloid cardioplegia. The incidence of arrhythmias, inotropic support requirement, and length-of-stay in the intensive care unit were evaluated. RESULTS: During reperfusion, there was no difference in incidence of arrhythmias; however, in the postoperative period group I had a lower incidence of arrhythmias (p = 0.001). Inotropic support (p = 0.003) and length-of-stay in the intensive care unit (p = 0.037) were lower in group I. There were no deaths in either group. CONCLUSIONS: It was concluded that myocardial protection with Bretschneider solution effectively decreases incidence of arrhythmias, inotropic support, and length-of-stay in the intensive care unit.

Left atrial reduction and mitral valve surgery: the "functional-anatomic unit" concept.

The desired outcome for patients undergoing mitral valve surgery includes both good function of the mitral valve, and preservation and restoration of sinus rhythm. To achieve such an outcome, we evolved the concept of the left atrium and mitral valve as a "functional anatomic unit." In this report, we describe a technique for reduction in left atrial size, isolation of the pulmonary veins, and amputation of the left atrial appendage in combination with mitral valve repair. We performed such a procedure in 4 patients, with rheumatic mitral valve disease and chronic atrial fibrillation, with restoration of good valve function and sinus rhythm at 16 to 20 months after surgery.

[Treatment with intrapleural streptokinase for coagulated hemothorax after cardiac surgery with cardiopulmonary bypass]. / Tratamiento con estreptocinasa intrapleural del hemotórax coagulado posterior a cirugía cardíaca con derivación cardiopulmonar.

INTRODUCTION AND OBJECTIVES: Coagulated hemothorax is a complication of cardiac surgery with cardiopulmonary bypass. The objective of this study was to present the authors' experience in the intrapleural infusion of streptokinase for the treatment of this complication. METHODS: From January 1996 to June 1999, nine patients (6 males, 3 females, age range: 1-75 years) were clinically and radiographically diagnosed with coagulated hemothorax after cardiac surgery. All patients were treated with intrapleural infusion of streptokinase at a standard dose of 250,000 units in adult patients and 12,000 U/kg in pediatric cases. In cases of occluded chest drainage, the position of the patient was changed and drainage was opened. RESULTS: In all the cases clinical and radiological improvement was observed and 100 to 200 ml of hemothorax was obtained on drainage. One patient died of multiorgan failure due to the underlying disease not related to the procedure. No alteration were observed in hematological tests including coagulation. The other 8 patients were discharged from hospital and remain without pulmonary compromise to date. CONCLUSION: Treatment of coagulated hemothorax with intrapleural infusion of streptokinase is a useful procedure and avoid the need for surgical drainage of hemothorax.

Direct communication between right pulmonary artery and left atrium.

A case of direct communication between right pulmonary artery and left atrium is reported. The diagnosis was made before surgical correction. A surgical ligation of the fistula resolved the cyanosis of the patient. Selective angiocardiogram of the right pulmonary artery 4 months after surgery revealed no residual shunt. This very rare malformation should be considered in the clinical setting of unexplained cyanosis. This is the number 50 case reported in the literature.

Theoretical aspects of the neurobiological integration of memory.

Whenever a peripheral structure like the visual system captures information, the input signal reverberates in circuits of neurons, which send it thereafter towards: (a) the motor system, triggering a specific response, evoked by a short-term memory mechanism; and (b) the hippocampus, to produce long-term potentiation or depression. Two different processes regulate short-term memory: (1) Homosynaptic depression that inhibits neurotransmitter release by means of a decrease in Ca++ inflow, and an increase in calmodulin affinity for synaptic vesicles; and (2) Heterosynaptic facilitation that triggers neurotransmitter release, whenever serotonin activates a proteinkinase A. Besides carrying out a brief review on the matter, we support two different physiological explanations with regard to: (a) ion exchange process and the interstitial pH during habituation; and (b) the possibility of a sensitive presynaptic neuron interaction within the habituated reverberant circuit, to trigger dishabituation. We also propose the term 'time-mediated stimulatory action dependent' to name those serotonin receptors that may lead to a rapid or a delayed postsynaptic onset responses.

Effect on acute rejection reaction and survival of the heart with the addition of dextran 60 to conventional immunosuppressive therapy in an experimental model of heterotopic heart transplantation.

BACKGROUND: Rejection reaction is an important complication in heart transplantation. Recent physiopathological findings suggest new immunosuppressive alternatives such as the use of substances that block interaction between leukocytes and endothelium or subsequent events. The objective of this work was to evaluate the effect of the combination of dextran 60 and conventional immunosuppressive therapy. METHODS: We used Sprague-Dawley rats, both sexes, with mean weight of 317.3 +/- 31.3 g on which we carried out heterotopic heart transplantation and then randomized into four groups. All groups received cyclosporine (2 mg/kg/day) and prednisone (0.5 mg/day). Group I (n = 5) also received 0.5 cc/kg/day of dextran 60, group II (n = 5) 1.0 cc/kg/day of dextran 60, group III (n = 5) 2 cc/kg/day, and group IV (n = 4) 0.9% saline solution 0.5 cc/kg/day. The incidence and severity of rejection reaction was evaluated as survival of transplanted hearts. RESULTS: Significant differences were found between groups III and IV for incidence of rejection reaction (p = 0.039). However, there were no differences among groups (grade 3A or 3B) in the magnitude of the rejection reaction. Survival of hearts was better in all groups receiving dextran 60 (p = 0.031). CONCLUSION: It was concluded that dextran 60 improves survival of transplanted hearts and decreases incidence of rejection reaction.

[Atrioventricular discordance. Clinico-surgical experience 1990-2000]. / Discordancia atrioventricular. Experiencia clínico-quirúrgica 1990-2000.

OBJECTIVE: To know the incidence of ventriculoarterial connections combined with atrioventricular discordance, associated lesions and surgical results, including the first case with anatomical correction. METHOD: All patients with atrioventricular discordance by echocardiography from 1990 to March 2000 were analyzed. RESULTS: Thirty six patients with atrioventricular discordance were found. Ages ranged from 0.1 to 46 years, with a mean 9.2 years (SD 5.9 years). Atrial chambers were situs solitus in 88.9%, inversus in 11.2%. The ventriculoarterial connections were discordant in 28 (77.7%), double outlet right ventricle in 4 (11.1%) (one of them was a "criss cross" heart), single outlet (pulmonary atresia) in 4 (11.1%), and double outlet left ventricle in 1 (2.7%). Associated lesions: Ventricular septal defect with pulmonary stenosis or atresia was present in 21 (58%), ventricular septal defect with no pulmonary obstruction was observed in 10 (28%). Five had tricuspid regurgitation with right ventricular disfunction, (two adults). Surgical results: 22 (61%) required 28 surgical procedures: 8 (36%) were palliative and 19 (86%) were corrective, one of them was our first anatomical correction. Operative mortality in all was 40.1%, postoperative atrioventricular block was observed in 9 (40.1%). CONCLUSION: Right ventricular dysfunction is not uncommon. Surgical results revealed high mortality and high pacemaker requirement for atrioventricular block.

Aortic origin of the right pulmonary artery associated with ductus arteriosus in an adult. A case report.

We describe the case of a 26-year-old female in functional class I (NYHA), with aortic origin of the right pulmonary artery associated with a persistent ductus arteriosus and severe pulmonary artery hypertension (101/40-70 mm Hg), which remained elevated (89/40-60 mm Hg) after the administration of 100% oxygen. Right pulmonary artery pressure (125/60-86 mm Hg) was higher than that of main pulmonary artery and similar to aorta pressure. The patient was successfully treated: surgical closure of the ductus arteriosus and end-to-end anastomosis between the pulmonary artery and right pulmonary artery were carried out. Systolic pulmonary arterial pressure, estimated by echocardiography Doppler, was 60 mm Hg six months after surgery. Cross-sectional echocardiogram showed the anastomosis of the right pulmonary artery with the main pulmonary artery. Pulmonary gammagraphy showed both lungs perfused through the main pulmonary artery; right lung perfusion was lesser than left lung perfusion, 30 vs. 70% respectively. Aortic origin of a right or left pulmonary artery is a heart disease seen in patients during the course of the first year of life. Its frequency is < 1% among all the congenital cardiopathies and the survival rate to adult life is very low. The originality of this paper is the presentation of a rare congenital cardiopathy treated surgically in an adult.

Aneurysm of the pulmonary trunk with patent arterial duct.

We present a 14-year-old female with a massive aneurysm of the pulmonary trunk occurring secondary to bacterial endocarditis of the patent arterial duct. Echo Doppler imaging, magnetic resonance and angiography confirmed the diagnosis. On intermediate follow-up after surgical correction, the echo studies and cardiac catheterization disclosed no residual lesions. The patient is now asymptomatic.

Orthotopic heart transplantation for dilated cardiomyopathy in a patient with persistent left superior vena cava and atresia of the right superior vena cava.

OBJECTIVE: To describe the surgical procedure of an orthotopic heart transplantation in a recipient with persistent left superior vena cava and atresia of right superior vena cava. EXPERIMENTAL DESIGN: Case report. PATIENT: A 43 year old male with persistent left superior vena cava, atresia of the right superior vena cava and dilated cardiomyopathy. INTERVENTIONS: Orthotopic heart transplantation with selective cannulation of the left superior vena cava via recipient coronary sinus for cardiopulmonary bypass. RESULTS: No perioperative complications, satisfactory postoperative course. No rejection episodes at 7 months postoperative with non invasive procedure surveillance. CONCLUSION: Technique described to preserve left superior vena cava is a useful alternative for this patient with no surgical complications.

Hypertonic-hyperosmotic solution modifies myoglobin levels in early reperfusion after ischemic cardiac arrest. Experimental model.

To evaluate the effect of reperfusion with hypertonic-hyperosmotic solution, cardiectomy was performed in 25 New Zealand white rabbits. Seven isolated hearts were submitted to 30 min of global ischemia and reperfused with oxygenated buffer for 60 min. Myoglobin and isoenzyme MB of creatine kinase concentrations were each measured in the effluent 15 min, and values were correlated (r = 0.5011, p = 0.015). After this procedure, 18 isolated hearts were randomized in two groups. Hearts of group I were reperfused with hypertonic-hyperosmotic solution (NaCl 7.5% dextran 60,000 MW) diluted in oxygenated buffer, and group II with oxygenated buffer. Myoglobin and coronary flow were measured in both groups, group I showed lower levels of myoglobin (p = 0.0069) and higher coronary flow (p = 0.028) than group II. In conclusion, changes in myoglobin concentration in the heart effluent are more sensitive than changes in isoenzyme MB of creatine kinase; thus, evaluation of this parameter may be useful in the detection of ischemia reperfusion injury. Additionally, hypertonic-hyperosmotic solution improves the coronary flow and has a protective effect against ischemia-reperfusion injury.

[Stents in aortic coarctation. Immediate results]. / Stents en coartación aórtica. Resultados inmediatos.

From September 1996 to March 1997 we implanted stents Palmaz (P-308 Johnson & Johnson) in six patients with aortic coarctation. Age ranged from 13 to 30 years (mean = 20), 3 female and 3 male. We implanted the stent without predilation. Balloon diameter was 12 mm in two cases and 15 mm in four cases for complete expansion we used 14 to 20 mm balloon diameter in five instances and in one case we used a dual balloon 15 + 15 mm. The gradient pre-stent ranged from 30 to 65 mmHg (mean = 44) and decreased to 0 mmHg in five cases and in one patient the residual gradient was 4 mmHg. Systolic aortic pressure pre-stent was 135 mmHg and decreased to 117 mmHg. There were no significant complications. In conclusion, we have demonstrated the feasibility of balloon-expandable stent implantation as a method of alleviation the obstruction in coarctation of the aorta in this group of patients. It is an excellent alternative to surgical treatment and it is better than balloon angioplasty that results in marked improvement in the angiographic appearance of the thoracic aorta. It eliminates the gradient, has minimum morbidity and no mortality, no aneurysm formation. Late restenosis and possible aneurysm formation remains an unlikely complication in view of the ample luminal diameter and the high velocity of flow.

Transversal trans-septal biatrial approach for mitral valve surgery.

A surgical approach to the mitral valve is very important to visualize all valvular and subvalvular structures. We have used a transversal trans-septal biatrial approach in some mitral procedures. From January 1994 to May 1994, 11 patients were operated on using this technique. Patient ages ranged from 28 to 74 years. Five cases (45.5%) were cardiac reoperations and six (54.5%) were first operations. Three case (27.3%) were mitral reconstructions, 3 (27.3%) were mitral replacement due to mechanical mitral valve thrombosis, 1 (9.1%) as a result of bioprosthetic mitral valve degeneration, 4 (36.4%) were mitral valve replacements for calcified mitral valve disease one case (9.1%) was tricuspid valve replacement due to severe tricuspid insufficiency. There were 4 case (36.4%) of tricuspid valvuloplasties besides the mitral procedures. There was no operative mortality, and all patients preserved their preoperative cardiac rhythm. No important bleeding or supra-ventricular arrhythmias were seen in any case. Aortic cross-clamping and extracorporeal circulation times were comparable with the traditional approach through the left atrial alone. So, we think that this is a very easy and useful technique to expose the mitral valve during some procedures above it, overall when the left atrium is small and total visualization of the mitral is not possible with the traditional approach through the left atrial alone.

Receptors, photoreception and brain perception. New insights.

Once photons have activated photosensitive cell receptors, a biochemical process mediated by G-proteins transforms the initial signal into nerve potentials. The generated impulses transmit the information through ganglion cells, after a complex interaction with other neurons by means of different neurotransmitters. Since visual function is processed in parallel, ganglion cells are divided into M-neurons which are in charge of capturing large objects, P-neurons capable of analyzing fine details and colors, and non-M, non-P neurons which are sensitive to changes in light intensity. Retina, bipolar and ganglion cells share circular receptive fields with an antagonistic surround whereas the lateral geniculate nucleus possesses rectangular receptive fields. Thus, when central cones are stimulated, ON-center cells depolarize, while OFF-center cells hyperpolarize. At the brain cortex, the magnocellular layers lead to orientation and achromatic perception, the parvocellular layers perform color vision in the blobs and achromatic contrast and orientation in the interblobs, and eventually, binocular perception is the result of multiple disparities phenomenon. On these bases, patients with agnosia for form and pattern or for depth and movement have been described. Likewise, color blindness is another disease that could be the result of photoreceptor dysfunctions or brain perception defects.

Control of myocardial reperfusion injury with hypertonic-hyperosmotic solution in isolated rabbit heart.

The effects of postischemic reperfusion were investigated in 14 isolated rabbit hearts in Langendorff preparation. Seven were controls and the others were reperfused with a sodium 7.5% and dextran 60 (60,000 MW) solution diluted with Krebs-Henseleit buffer to a sodium concentration of 150 mEq/l. The incidence of arrhythmias was lower in this group (p = 0.034). Coronary flow was higher than in controls (p = 0.035), the levels of isoenzyme MB of creatine kinase were lower than in controls (p = 0.035), myocardial water content was also lower (p = 0.047), and histological damage was reduced (p = 0.018). It was concluded that early reperfusion with 7.5% sodium chloride, 6% dextran 60 solution has a protective effect in the treatment of cardiac reperfusion injury.

Cellular receptors, acceptors and clinical implications.

Evidence of the existence of a special decodifier on the effector cells, with which inductor substances must interact in order to trigger their characteristic responses, has been found since the beginning of the century. These cytoplasmic sites are able to recognize, accept and receive the message transmitted by the inductor substance, giving rise to a specific cell response. Thus, the inductor-receptor binding complex interaction at the cellular level may alter permeability to ions as happens with neuro-transmitters, or can trigger pinocytosis in the case of apolipoproteins. Cellular receptors have been involved in the mechanism of action of several drugs and its dysfunction explains the physiopathology of a number of diseases. This may involve diminished clathrin protein synthesis triggering a defect in affinity, such as seen in malnutrition. It is also applicable in genetic disturbances, which are capable of precluding receptor development as in cases of familiar hypercholesterolemia.

[Cardiac myxoma. A report of 23 cases]. / Mixoma cardiaco. Presentación de 23 caso.

Twenty-three cases of cardiac myxoma are reviewed during a period of 11 years. Seventeen patients were females and 6 males with an average age of 36 years. All patients were symptomatic for an average period of time of 4 months. Dyspnea was the main symptom (91%), congestive heart failure (52%), murmurs (74%), atypical chest pain (65%), palpitations (52%), constitutional manifestation (48%), congestive heart failure (36%), embolic events (23%) and ventricular tachycardia as a first manifestation of a right ventricular myxoma in one case (4.5). In all patients the diagnosis of cardiac tumor was made during life. Among they, in 83%, by echocardiogram, 14%, by cardiac catheterization, and in one case (4.5%) with both methods. Seventy percent were located in the left atrium, 18% in the right atrium, 9% in the right ventricule and 4.5% to both right cavities. Two patients died while waiting surgery, one due to pulmonary emboli and another due to refractory congestive heart failure. In all 21 patients who were sent to surgery a direct correlation was seen with the echocardiographic findings. All 23 patients had a confirmatory histopathological diagnosis. There were no surgical deaths. Excision of the tumor resulted in marked symptomatic improvement. The follow up by echocardiography showed that surgery has been curative with no recurrence up till now. We consider that this entity, that is capable to simulate multiple cardiovascular diseases must be removed surgically once it has been diagnosed in order to avoid fatal complications.

Extraction of the autoperfused heart-lung block, experimental model.

The technique used by our group for the extraction of the canine autoperfused heart-lung block is described. This was used in 30 dogs, having a success rate of 24 total extractions and function times from 30 minutes to 13 hours." The complications observed were: arterial rupture upon cannulation, aortic rupture upon binding, ventricular fibrillation before completing extraction, and bleeding of the block with subsequent emptying of the reservoir. It is concluded that the technique described is adequate for the extraction of the canine block, although it is still necessary to know better its hemodynamic, biochemical and respiratory behavior.