207 resultados para Pulmonary mechanics
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OBJECTIVE: To demonstrate the feasibility and safety of simultaneous catheterization and mapping of the 4 pulmonary veins for ablation of atrial fibrillation. METHODS: Ten patients, 8 with paroxysmal atrial fibrillation and 2 with persistent atrial fibrillation, refractory to at least 2 antiarrhythmic drugs and without structural cardiopathy, were consecutively studied. Through the transseptal insertion of 2 long sheaths, 4 pulmonary veins were simultaneously catheterized with octapolar microcatheters. After identification of arrhythmogenic foci radiofrequency was applied under angiographic or ultrasonographic control. RESULTS: During 17 procedures, 40 pulmonary veins were mapped, 16 of which had local ectopic activity, related or not with the triggering of atrial fibrillation paroxysms. At the end of each procedure, suppression of arrhythmias was obtained in 8 patients, and elimination of pulmonary vein potentials was accomplished in 4. During the clinical follow-up of 9.6±3 months, 7 patients remained in sinus rhythm, 5 of whom were using antiarrhythmic drugs that had previously been ineffective. None of the patients had pulmonary hypertension or evidence of stenosis in the pulmonary veins. CONCLUSION: Selective and simultaneous catheterization of the 4 pulmonary veins with microcatheters for simultaneous recording of their electrical activity is a feasible and safe procedure that may help ablation of atrial fibrillation.
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We report new percutaneous techniques for perforating the pulmonary valve in pulmonary atresia with intact ventricular septum, in 3 newborns who had this birth defect. There was mild to moderate hypoplastic right ventricle, a patent infundibulum, and no coronary-cavitary communications. We succeeded in all cases, and no complications related to the procedure occurred. The new coaxial radiofrequency system was easy to handle, which simplified the procedure. Two patients required an additional source of pulmonary flow (Blalock-Taussig shunt) in the first week after catheterization. All patients had a satisfactory short-term clinical evolution and will undergo recatheterization within 1 year to define the next therapeutic strategy. We conclude that this technique may be safely and efficiently performed, especially when the new coaxial radiofrequency system is used, and it may become the initial treatment of choice in select neonates with pulmonary atresia and intact ventricular septum.
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We report the clinical findings, pathophysiology, diagnostic characteristics, and surgical repair of anomalous origin of the left coronary artery from the pulmonary artery in a 26-year-old female patient with a clinical diagnosis of coronary heart disease.
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The case of a 16-year-old patient with atrioventricular tachycardia caused by a single left anterolateral accessory pathway is reported. When the patient underwent radiofrequency ablation, a lesion on the mitral annulus lateral wall produced changes in the retrograde atrial activation pattern determined by that pathway; changes ranged from a delay in depolarization of the annulus posterior portions to full left atrium counterclockwise activation. Such phenomena were probably caused by a block in the isthmus between the annulus and the lower left pulmonary vein ostium. This case illustrates the importance of the mitral-pulmonary isthmus in the process of left atrium activation, an alert to changes induced by its unintentional block during accessory pathway ablation.
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OBJECTIVE: To identify the left inferior pulmonary vein as an indirect marker of increased pulmonary flow in congenital heart diseases.METHODS: We carried out a prospective consecutive study on 40 patients divided into 2 groups as follows: G1 - 20 patients diagnosed with congenital heart disease and increased pulmonary flow; G2 (control group) - 20 patients who were either healthy or had congenital heart disease with decreased or normal pulmonary flow. We obtained the velocity-time integral of the left inferior pulmonary vein flow, excluding the "reverse A" wave, with pulsed Doppler echocardiography.RESULTS: In G1, 19 out of the 20 patients had well-identified dilation of the left inferior pulmonary vein. No G2 patient had dilation of the left inferior pulmonary vein. Dilation of the left inferior pulmonary vein in conditions of increased pulmonary flow had sensitivity of 95%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 95% (1 false-negative case). The integral of time and velocity of the pulmonary venous flow obtained with pulsed Doppler echocardiography was greater in the G1 patients (G1=25.0±4.6 cm versus G2=14.8±2.1 cm, p=0.0001).CONCLUSION: The identification of dilation of the left inferior pulmonary vein suggests the presence of congenital heart disease with increased pulmonary flow. This may be used as an indirect sign of increased flow, mainly in malformations of difficult diagnosis, such as atrial septal defects of the venous sinus or coronary sinus type.
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A 50-year-old man developed recurrent angina 1 year after coronary artery bypass surgery. The patient was found to have a large fistula involving branches of the internal mammary artery graft and the left pulmonary artery. In the absence of another clear cause for the patient's symptoms, we speculated that our patient's angina and abnormal stress nuclear study were due to coronary steal. In patients with a history of coronary bypass grafting, fistula formation between graft and native vessels should be considered as a possible cause of early recurrent angina.
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We describe the case of a 40-day-old female patient with a history of breathlessness since birth who was referred to our hospital for surgical correction of common arterial trunk. The invasive investigation disclosed a Fallot¢s tetralogy anatomy associated with an anomalous origin of the left pulmonary artery from the ascending aorta. Immediately after diagnosis, the patient underwent a successful total surgical correction of the defect, including simultaneous anastomosis of the left pulmonary artery to the pulmonary trunk.
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OBJECTIVE: To analyze parameters of respiratory system mechanics and oxygenation and cardiovascular alterations involved in weaning tracheostomized patients from long-term mechanical ventilation after cardiac surgery. METHODS: We studied 45 patients in their postoperative period of cardiac surgery, who required long-term mechanical ventilation for more than 10 days and had to undergo tracheostomy due to unsuccessful weaning from mechanical ventilation. The parameters of respiratory system mechanics, oxigenation and the following factors were analyzed: type of surgical procedure, presence of cardiac dysfunction, time of extracorporeal circulation, and presence of neurologic lesions. RESULTS: Of the 45 patients studied, successful weaning from mechanical ventilation was achieved in 22 patients, while the procedure was unsuccessful in 23 patients. No statistically significant difference was observed between the groups in regard to static pulmonary compliance (p=0.23), airway resistance (p=0.21), and the dead space/tidal volume ratio (p=0.54). No difference was also observed in regard to the variables PaO2/FiO2 ratio (p=0.86), rapid and superficial respiration index (p=0.48), and carbon dioxide arterial pressure (p=0.86). Cardiac dysfunction and time of extracorporeal circulation showed a significant difference. CONCLUSION: Data on respiratory system mechanics and oxygenation were not parameters for assessing the success or failure. Cardiac dysfunction and time of cardiopulmonary bypass, however, significantly interfered with the success in weaning patients from mechanical ventilation.
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OBJECTIVE: To differentiate the nature of functional cardiorespiratory limitations during exercise in individuals with chronic obstructive pulmonary disease (COPD) or congestive heart failure (CHF) and to determine indicators that may help their classifications. METHODS: The study comprised 40 patients: 23 with COPD and 17 with CHF. All individuals underwent maximal cardiopulmonary exercise testing on a treadmill. RESULTS: The values of peak gas exchange ratio (R peak), peak carbon dioxide production (VCO2 peak), and peak oxygen ventilatory equivalent (V E O2 peak) were higher in the patients with CHF than in those with COPD, and, therefore, those were the variables that characterized the differences between the groups. For group classification, the differentiating functions with the R peak, VCO2 peak (L/min), and V E O2 peak variables were used as follows: group COPD: - 44.886 + 78.832 x R peak + 5.442 x VCO2 peak + 0.336 x V E O2 peak; group CHF: - 69.251 + 89.740 x R peak + 8.461 x VCO2 peak + 0.574 x V E O2 peak. The differentiating function, whose result is greater, correctly classifies the patient's group as 90%. CONCLUSION: The R peak, VCO2 peak, and V E O2 peak values may be used to identify the cause of the functional cardiorespiratory limitations in patients with COPD and CHF.
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We report a rare case of anomalous origin of the left coronary artery from the pulmonary trunk in a 45-year-old woman. The approach and technique used for selective catheterization of an anomalous left coronary artery arising from the pulmonary trunk are described. Six years after diagnosis, echocardiography showed left ventricular disfunction, and surgical treatment was indicated again. The origin of the left coronary artery from the pulmonary trunk was closed, and the postoperative period was uneventful, with recovery of left ventricular function and disappearance of ischemic features on stress myocardial perfusion imaging with 99m Tc-sestamibi, performed 4 weeks after surgery.
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OBJECTIVE: To verify the hypothesis that the pulmonary vein pulsatility index is higher in fetuses of diabetic mothers than it is in normal fetuses of nondiabetic mothers. METHODS: Twenty-four fetuses of mothers with either gestational or previous diabetes (cases), and 25 normal fetuses of mothers without systemic disease (control) were examined. Fetuses were examined through prenatal Doppler and color flow mapping. The pulmonary vein pulsatility index was obtained by placing the pulsed Doppler sample volume over the right superior pulmonary vein and applying the formula (systolic velocity - presystolic velocity)/mean velocity. RESULTS: The mean gestational age of the study fetuses was 30.3±2.7 weeks, and gestational age of the controls was 29±3.3 weeks, with no significant difference in gestational age between groups (p=0.14). Fetuses of diabetic mothers had a mean pulmonary vein pulsatility index of 1.6±1, and those of the control group had an index of 0.86±0.27. CONCLUSION: Fetuses of diabetic mothers had pulmonary vein pulsatility indexes (parameter easily obtained through Doppler echocardiography that may be related to fetal diastolic function) higher than those in fetuses of mothers with normal glycemia.
Hemodynamic Effects of Noninvasive Ventilation in Patients with Venocapillary Pulmonary Hypertension
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Background: The hemodynamic effects of noninvasive ventilation with positive pressure in patients with pulmonary hypertension without left ventricular dysfunction are not clearly established. Objectives: Analyze the impact of increasing airway pressure with continuous positive airway pressure on hemodynamic parameters and, in particular, on cardiac output in patients with variable degrees of pulmonary hypertension. Methods: The study included 38 patients with pulmonary hypertension caused by mitral stenosis without left ventricular dysfunction or other significant valvulopathy. The hemodynamic state of these patients was analyzed in three conditions: baseline, after continuous positive pressure of 7 cmH2O and, finally, after pressure of 14 cmH2O. Results: The population was composed of predominantly young and female individuals with significant elevation in pulmonary arterial pressure (mean systolic pressure of 57 mmHg). Of all variables analyzed, only the right atrial pressure changed across the analyzed moments (from the baseline condition to the pressure of 14 cmH2O there was a change from 8 ± 4 mmHg to 11 ± 3 mmHg, respectively, p = 0.031). Even though there was no variation in mean cardiac output, increased values in pulmonary artery pressure were associated with increased cardiac output. There was no harmful effect or other clinical instability associated with use application of airway pressure. Conclusion: In patients with venocapillary pulmonary hypertension without left ventricular dysfunction, cardiac output response was directly associated with the degree of pulmonary hypertension. The application of noninvasive ventilation did not cause complications directly related to the ventilation systems.