Avaliaçäo clínica do desempenho de um novo eletrodo bipolar endocárdico de fixaçäo passiva revestido com esteróide / Clinical evaluation of the new ventricular bipolar lead with passive fixation and steroid eluting

O propósito deste estudo clínico é demonstrar a segurança e eficácia do cabo-eletrodo bipolar modelo 5092 (Medtronic, Inc.), quando usado para estimulaçäo e sensibilidade cardíaca. O estudo verificará também que o cado-eletrodo modelo 5092 pode ser implantado com sucesso usando as técnicas de manuseio dos cabos-eletrodos padräo. As informaçöes opera a manipulaçäo do cabo-eletrodo seräo usadas para recomendar procedimentos de implante e para instruçöes de novos usos ao colocá-lo no mercado. Uma revisäo dos métodos de estudo e uma apresentaçäo abrangente dos resultados estäo incluídas neste relato. Realizou-se uma avaliaçäo prospectiva do cabo-eletrodo modelo 5092 usando os resultados de estudos clínicos do modelo 5024M como um controle. A semelhança do modelo 5092, o modelo 5024M é também de silicone, bipolar, coaxial, transvenoso de fixaçäo passiva, e revestido com esteróide. Os dados dos pacientes para o modelo 5092 neste relato foram coletados no implante, na pré-alta hospitalar, e duas semanas, um mês e três meses após o implante. Os dados dos pacientes continuaräo sendo coletados até seis meses após o implante e a partir daí a cada seis meses até o final do estudo.

Efeito do esteróide nos limiares agudos de um eletrodo atrial e ventricular de fixaçäo ativa / Steroid effect of an active fixation lead on acute atrial and ventricular pacing thresholds

OBJETIVO: Comparar a performance de um eletrodo bipolar permanente com fixaçäo ativa e colar de esteróides, com outro eletrodo semelhante, mas sem o colar de esteróide. MATERIAL E MÉTODO: Este estudo foi realizado em 2 fases em 3 centros no Brasil: na fase atrial eletrodos Sweet Tip Rx e Sweet Tip foram implantados em 16 e 8 pacientes, respectivamente. Em todos os pacientes os limiares de voltagem (largura de pulso = 0,5ms) e a largura de pulso (amplitude = 1,5V) foram medidos por ocasiäo da alta hospitalar, 2 semanas e 3 ou 4 meses após o implante. RESULTADOS: Na avaliaçäo de 2 semanas a média dos limiares de voltagem, foi de 0,57ñ0,04V para o Sweet Tip Rx e 1,0ñ0,19V para o Sweet Tip (p<0,02). Para os eletrodos ventriculares, essa média foi de 0,66ñ0,07V para o Sweet Tip Rx e 1,50ñ0,23V para o Sweet Tip (p<0,01). Para os eletrodos atriais os valores médios dos limiares de largura de pulso nesta etapa foram 0,10ñ0,02ms para o Sweet Tip Rx e 0,19ñ0,07ms para o Sweet Tip (p>0,49) e para os eletrodos ventriculares 0,14ñ0,02ms para o Sweet Tip Rx e 0,31ñ0,05ms para o Sweet Tip (p<0,01). Na última avaliaçäo, os valores médios dos limiares de largura de pulso dos eletrodos atriais foram 0,06ñ0,01ms para o Sweet Tip Rx e 0,14ñ0,05ms para o Sweet Tip (p<0,26) e, para os eletrodos ventriculares 0,09ñ0,01ms para o Sweet Tip Rx e 0,50ñ0,14ms para o Sweet Tip (p<0,01). Näo houve diferença significativa entre a impedância dos dois tipos de eletrodos nas avaliaçöes tardias. CONCLUSÄO: Os eletrodos envolvidos com esteróides tiveram um limiar significativamente menor após o implante.

[Pacemaker with sensor of contractility regulated by autonomic nervous system variations in chronic Chagas cardiomyopathy]. / Marcapasso com sensor de contratilidade regulado pelas variações do sistema nervoso autônomo na miocardiopatia chagásica crônica.

PURPOSE: To analyse the performance of the artificial cardiac stimulation with the VVIR pacemaker whose sensor is adjusted by the variations of the autonomic nervous system in Chagas disease patients with deficiency of the conduction system. METHODS: Forty-seven Chagas disease patients have been studied, 28 male between 24 and 68 years old, 36 patients had complete AV block, 8 had 2nd degree AV block and the other 3 had sinusnode disease. The patients were in class I (4), II (15), III (16) and IV (12) according to the NYHA. A 12-month-follow-up with constant clinical evaluations was carried out after pacemaker implantation. Patients were divided in 2 different groups according to the HR at rest--group 1: > 65 beats per minute (bpm) and group 2: < or = 65 bpm, for a comparative study considering: 1) HR at stress test after the implantation; 2) arterial blood pressure at rest after the implantation and, 3) evaluation of the identified electrodes such as TIR-60-UP and others. RESULTS: The group 1 had greater HR at rest, and a smaller variation of values at stress than group 2. This shows that with this type of stimulation system it is possible to control each patient separately. The values of blood pressure at rest and during stress were not different between groups. According to the factors analysed the TIR-60-UP electrode had the same performance as the others. CONCLUSION: The VVIR pacemaker with the sensor adjusted by the ANS variations has provided the Chagas patients with a restoration of their physiological mechanisms. 74% of them had the improvement of either one or 2 functional classes.

Estimulaçäo com adaptaçäo de freqüência controlada pelo sistema nervoso autônomo - uma avaliaçäo clínica / ANS controlled rate-adaptive pacing: a clinical evaluation

Para o tratamento da incompetência cronotrópica, marcapassos com adaptaçäo em freqüência baseados em diferentes sinais de sensores têm sido desenvolvidos, visando restaurar o mecanismo fisiológico em malha fechada e utilizando informaçäo fornecida pelo sistema nervoso autônomo (SNA). A medida da impedância cardíaca unipolar permite a monitorizaçäo do estado de contraçäo do coraçäo, diretamente relacionado ao tônus simpático. Marcapassos uni ou bicamerais com sistemas responsivos controlados pelo SNA foram implantados em 262 pacientes em vários centros clínicos. Protocolos de exercícios clíncos, monitorizaçäo por Holter, testes de estresse psicológico e estudos adicionais visando uma variaçäo intencional do tônus simpático confirmaram a resposta fisiológica em freqüência para os vários tipos de mudanças hemodinâmicas.

Estudo multicêntrico comparativo de quatro diferentes tipos de sensores: atividade, acelerômetro, temperatura e período de pré-ejeçäo / Comparative study with different rate adaptive pacing systems

Recentemente diferentes princípios têm sido utilizado para estimular o coraçäo na tentativa de recuperar o débito cardíaco. Neste estudo multicêntrico, foram comparadas as respostas à estimulaçäo por 4 tipos de sensores, sendo 3 tipos de resposta de alça aberta (atividade física, acelerômetro e temperatura venosa central) implantados em 30 (SSIR-8 e DDDR-22), 9(SSIR-5 e DDDR-4) e 12 (SSIR) pacientes respectivamente. Um outro sensor do tipo alça fechada, sensível às variaçöes do sitema nervoso autôno, foi implantado em 57 pacientes, todos no modo DDDR. Os resultados obtidos durante a realizaçäo de atividade física diária, de teste ergométrico e de Holter de 24 horas foram comparados sendo possível observar uma maior fidelidade na curva de resposta de frequência frente a atividade física, nos pacientes submetidos à estimulaçäo de alça fechada

ANS controlled closed loop cardiac pacing - a multicenter study

A pacemaker system has been developed that in controlled by the autonomic nervous system (ANS). It measures the intracardiac impedance and derives a measure for the sympathetic drive from specific characteristics of the impedance curves. The pacing rate is adapted to this measure and thus is put under closed loop control of the ANS. In this paper the validity of the sensor principle and calculation of pacing rate were investigated. The formation of a closed-loop pacing rate regulation was demonstrad. Furthermore the entire system was validated in a clinical stting evaluating rate adaptive performance and benefit for the patient.

Acute myocardial infarction treated with intravenous streptokinase: 6-year follow-up.

Our objective was to investigate variables which, although occurring during the acute period, could influence the medium (1st year) and long-term (6th year) survival of infarcted patients. Of a total of 332 patients treated consecutively and prospectively according to the same protocol which included intravenous streptokinase, 305 survived the hospital phase and represent the study population. Mean patient age was 55.6 +/- 10 years and mean follow-up time was 3.33 years, with 1008.59 patient-years. The clinical course of the group was analyzed according to the following variables: left ventricle ejection fraction, hypotension per/peri streptokinase infusion, CK-MB peak, previous myocardial infarction, number of obstructed coronaries, reinfarction, sex, 'definitive' treatment, residual obstruction, age, pain/streptokinase infusion interval, patency of the 'culprit' coronary and infarct location. Overall, patient survival was 93.8 +/- 1.4% during the 1st year and 83.7 +/- 2.6% at the 6th. The following groups showed significantly different (log-rank) survivals: (a) 1st year: 94.6% for absence and 82.6% for presence of reinfarction (P = 0.0451); 97.9% for inferior and 91.4% for anterior infarct location (P = 0.044); 96.4% for ejection fraction > 50% and 90.6% for ejection fraction < or = 50% (P = 0.0187); 96.5% for angioplasty/surgery and 90.1% for clinical treatment (P = 0.0028); 95.5% for absence and 80.6% for presence of previous infarct (P = 0.0001). (b) 6th year: 88.3% for ejection fraction > 50% and 73.9% for ejection fraction < or = 50% (P = 0.028); 87.4% for < or = 65 and 66.4% for > 65 years (P = 0.0114); 89.6% for aggressive and 76.8% for conservative treatment (P = 0.013); 86.6% for absence and 60.7% for presence of previous infarct (P = 0.0009).

[The cholesterol profile in the city of São José do Rio Preto]. / Perfil do colesterol na cidade de São José do Rio Preto.

PURPOSE: To analyze: a) the cholesterol profile in adults older than 29 years, from São José do Rio Preto (300,000 inhabitants), city located in one of the country's richest regions; b) the variables that correlated with cholesterolemia. METHODS: An specialized firm was hired, and data was obtained through quantitative research, where a survey was done, using a sample stratified by sex and age; the error limits admitted was +/- 4%, for a 95% confidence interval, and Reflotron was utilized for cholesterol measurements. It was studied 672 persons (47% men), with mean age of 47.15 +/- 12.28 years; 35% were between 30 and 39 years, 25% between 40 and 49.22% between 50 and 59, and 18% were 60 or more years old. Thirteen variables were compared with cholesterolemia through simple regression; following, six of them, selected as predictors by stepwise regression, were compared with cholesterol through multiple regression analysis. RESULTS: a) Cholesterol levels: 192.5 +/- 48.9 mg/dl on global average, with 187.6 +/- 53.3 for men and 196.8 +/- 44.2 for women (p = 0.01, 95% CI 2.3 to 17.1); 176.5 +/- 44.7 mg/dl for people > or = 30 < 40 years old, 191.3 +/- 51.7 for those > or = 40 < 50 years (p = 0.002, 95% CI 4.6 to 24.2), 206.8 +/- 44.4 for those > or = 50 < 60 years (p = 0.005, 95% CI 4.6 to 26.4), and 208.5 +/- 47.8 for those > or = 60 years (p = 0.765,95% CI 9.5 to -12.5); 62% of the population showed < or = 200 mg/dl, and 16% > or = 240; b) through simple regression analysis, significant correlations were found between cholesterolemia and: age (p < 0.001), systolic (p < 0.001) and diastolic (p < 0.001) arterial pressures, diet (any, the great majority hypocaloric, p = 0.001), height (inverse correlation, p = 0.003), and female gender (p = 0.011); under multiple regression analysis, significant correlations were found for age (p < 0.001), educational level (p < 0.001), systolic arterial pressure (p < 0.001), weight (p = 0.004) and height (inverse correlation, p = 0.012). CONCLUSION: In the population older than 29 years, from São José do Rio Preto: a) the mean cholesterolemia is 192.5 +/- 48.9 mg/dl, being significantly higher for women, in relation to men, and showing significant increases between 3rd, 4th and 5th decades of life; b) correlated significantly with cholesterolemia, through simple regression analysis: age, systolic and diastolic arterial pressures, diet, height (inverse), and female gender; under multiple regression analysis: age, educational level, systolic arterial pressure, weight and height (inverse).

Autonomic nervous system controlled closed loop cardiac pacing.

A multicenter clinical study is presented, which focuses on the reestablishment of closed loop cardiac control in patients with chronotropic insufficiency. Using the information about sympathetic tone contained in the myocardial contractility, it is possible to reconnect the heart rate to the physiological control mechanisms. Intracardiac impedance is measured with the ventricular electrode and the ventricular inotropic parameter (VIP) is derived from that. The VIP serves directly as input to the control of heart rate by the pacemaker. Over 200 patients have received autonomic nervous system (ANS) controlled pacemakers. The patient-pacemaker system was investigated in different ways. This included standard exercise tests, long-term studies of every day activities over 24 hours, psychological, and pharmacological challenges. To prove the validity of the approach we specifically looked at (1) the appropriateness of changes in paced heart rate with sympathetic tone during exercise, (2) the correlation between heart rate and sinus rate, if detectable, and (3) the correlation between the echocardiographically determined preejection period (PEP) and the VIP controlled heart rate.

[Measuring intracardiac impedance for the determination of sympathetic nerve activity in frequency-adapted electrostimulation--Part 2: Clinical results]. / Intrakardiale Impedanzmessung zur Bestimmung der Sympathikusaktivität bei frequenzadaptiver Elektrostimulation--Teil 2: Klinische Ergebnisse.

The results of a multicenter clinical study involving patients receiving the first ANS controlled rate adaptive pacemaker are presented. In the patients with primary or secondary chronotropic insufficiency, it is possible to reestablish the closed loop control system that includes the baroreceptors, the medulla oblongata, the cardiac output and the mean arterial blood pressure. This system serves to keep the blood pressure constant in the face of changing demands on the circulation. Utilizing intracardiac impedance measurements, the myocardial contractility can be determined, which contains information about the current sympathetic tone, and thus represents an excellent physiological input for a rate adaptive mechanism. The results presented are taken from a study population of over 200 patients. The objective evaluation of this new approach was performed echocardiographically, by ergometry and 24-hour Holter monitoring.

[Malignant schwannoma metastasizing to the heart]. / Schwannoma maligno metastatizando para o coração.

We introduce the case of a 34-year-old male with a malignant metastasizing tumor in the heart associated with skin manifestations. The patient was submitted to heart surgery to resect the tumor. The correct diagnosis was done by pathological findings and immunohistochemical methods and showed, malignant schwannoma.

[Constrictive pericarditis as differential diagnosis of hepatic disease]. / Pericardite constrictiva como diagnóstico diferencial de doença hepática.

Constrictive chronic pericarditis in a 13-year-old male patient was previously treated as chronic hepatitis for seven years, with the use of furosemide and spironolactone. Investigation for diagnosis included chest radiography, echo-doppler-cardiography, thoracocentesis with pleural biopsy and computerized tomography of chest, and showed ventricular diastolic restriction due to constrictive chronic pericarditis. After eight weeks of tuberculostatic treatment, the patient was submitted to hemodynamic study that confirmed the diagnosis and a pericardiectomy was performed. Long-term follow-up showed regression of diastolic restriction and decrease of hepatosplenomegaly and of jugular stasis. Tuberculostatic drugs were given for 12 months postoperatively, associated to corticosteroids.

IMC bovine pericardial valve: 11 years.

From 1977 to 1988, 10,812 bovine pericardial valves were produced by IMC Biomédica and implanted. One thousand one hundred ninety-three were implanted by our group at IMC, including 666 exclusively in the mitral position. We are presenting our study of those mitral patients. Of the 663 patients, 586 were adults (over 21 years of age) and 77 were youngsters (under 21). Hospital mortality was 9.2%; 13.2% for the first 5.5 years (group 1) and 6.3% for the second 5.5 years (group II). Eleven year follow-up was 98.8% complete and the mean time was 3.8 years. The actuarial survival was 74.3% +/- 6.5% for the youngsters and 73.0% +/- 3.7% for the adults. The fatal valve-related late complications (death from thromboembolism, calcification, and endocarditis) had an incidence of 1% per patient-year as follows: (1) endocarditis, 0.6% per patient-year; (2) calcification 0.1% per patient-year; and (3) cerebral vascular accident, 0.3% per patient year. The actuarial study revealed 95.0% +/- 1.0% freedom from fatal complications related to the prosthesis. The nonfatal valve-related late complications had an incidence of 2.9% per patient-year as follows: (1) endocarditis, 0.5% per patient-year; (2) calcification, 1.8% per patient-year; (3) cerebral vascular accident, 0.3% per patient-year; (4) periprosthetic leakage, 0.2% per patient-year; and (5) rupture, 0.1% per patient-year.(ABSTRACT TRUNCATED AT 250 WORDS)

[Univentricular heart: angiographic features in 31 patients]. / Coração univentricular: aspectos angiográficos em 31 pacientes.

PURPOSE: Evaluation of angiographic features of univentricular heart. METHODS: Thirty-one patients were divided into 3 groups according to morphological type of univentricular heart: left ventricle type, right ventricle type and undetermined. They were studied for atrio-ventricular junction, position of rudimentary chamber in relation to principal chamber, ventricle-arterial junction, the position of the two great arteries in relation to each other and whenever possible, the origin of the coronary arteries. RESULTS: There were 16 cases of left ventricle type with A-V junction through 2 valves in 8 and through single valve in 6. The rudimentary chamber position was superior and to the right in 4 cases of dextrocardia and superior and to the left in 8 of levocardia. The ventricle-arterial junction was discordant in 9 patients and concordant in 4, double outlet of rudimentary chamber in 2 and single outlet in 1. The aorta was anterior to the pulmonary artery in 13 patients. Anomalous origin of the coronary arteries occurred in 5 of 9 cases studied. Right ventricle type occurred in 9 patients with absence of one of the A-V junctions in 5. Trabecular pouch was seen in 6 patients, posterior and inferior positioned in all of them. Double outlet from principal chamber occurred in 8 patients. The aorta was anterior in 66.6%. Undetermined type occurred in 6 patients with A-V junction through single valve in 5. In 3 there was double outlet from principal chamber showing pulmonary stenosis and in the remaining 3 there was pulmonary atresia. CONCLUSION: Discordant ventricle-arterial junction is common for left ventricle type; trabecular pouch is frequent in right ventricle type; single A-V valve is common for undetermined type; obstruction of pulmonary flow happens in all 3 types but it is more frequent in undetermined type; the aorta is anterior to the pulmonary artery in most cases; it is common the anomalous origin of the coronary arteries from the aortic sinus.

[Survival and predictive factors of late mortality in the surgical treatment of aortic stenosis]. / Sobrevida e fatores preditivos da mortalidade tardia no tratamento cirúrgico da estenose aórtica.

PURPOSE: Study of 161 patients submitted to aortic valve replacement due to aortic stenosis to evaluate survival and predictive factors of late mortality. METHODS: The mean age was 45.8 years +/- 13.2 and 122 patients were men. Surgical mortality was 6.8%. The survival actuarial curve showed 59.28% of the patients alive after 16 years. Among the survival 62.3% +/- 10% were event free, including prosthesis thrombosis, thromboembolism, infective endocarditis and reoperation. Symptoms, age, gradient LV/Ao, ejection fraction (EF) and the compliance (CO) were related to prognosis. Sudden death after surgery was studied, with incidence of the 0.8 events/100 patients year. RESULTS: The asymptomatic patients had better evolution than symptomatic (p less than 0.05). The age above 60 years was not predictive of the prognosis in 10 years of follow-up, but no patients survived after 10 years. The gradient LV/Ao was not an important factor in the survival. The group with EF greater than 50% had 66.4% of survival, while the group with EF less than 50% survival was 39%. Normal or decreased compliance was not important in the survival. All patients with EF less than 50% always has decreased CO. Fifteen patients were dead due to heart failure and the most important predictive factor was the left ventricular dysfunction (p = 0.02). CONCLUSION: In aortic stenosis: a) severe ventricular dysfunction does not preclude the surgical treatment; b) the actuarial analysis suggests that EF less than 50% determines worse prognosis and always occurs with decreased CO; c) the excellent evolution of the asymptomatic patients does not generalize the surgical treatment in this phase; d) the incidence of the sudden death was not high after the surgical treatment; e) patients with pre-operative left ventricular dysfunction had greater mortality due to heart failure, than patients with normal left ventricular function; f) despite of the morbid events our results confirm the real benefit of the surgical treatment in the aortic stenosis.

[Fibrinolytic therapy in non-coronary diseases]. / Terapêutica fibrinolítica em doenças não coronarianas.

Utilization of fibrinolytic drugs in non-coronary diseases has been described since 1949, but despite of that, works about that subject are very rare in the literature. In this paper we discuss the cases of three patients that were treated with such compounds for pulmonary embolism, peripheral arterial embolism, and thrombosis in mechanical aortic prosthesis. All patients had excellent in-hospital outcome, and were totally asymptomatic at the discharge time. It is emphasized the clinical symptoms, sometimes unexpected, and the importance of the complementary tests not only in the disease's diagnosis, but also in some decisions that must be taken during the patient's evolution, where they can help us to decide, for example, about the correct moment to stop the thrombolytic infusion. In conclusion, fibrinolytic drugs can be utilized in the management of many affections that otherwise would be treated by emergency surgery.

Clinical and laboratory signs of reperfusion: are they reliable?

We studied 101 patients (88 men and 13 women, mean age 54.5 +/- 10 years) who arrived at the hospital during the first 6 hours of acute myocardial infarction evolution. Our objective was to assess the reliability of clinical and laboratory signs of recanalization using intravenous streptokinase as a thrombolytic agent. The mean time between the beginning of infusion and coronary arteriography was 53.83 +/- 43 hours. The positive predictive values for pain, arrhythmia, ST segment and enzymes were 97.9%, 94.2%, 91.8% and 90.8%, respectively; the negative predictive values were 46.8%, 40.8%, 37.2%, and 50% in the same order. Sensitivity was 65.7%, 62.8%, 58.4% and 77.6% and specificity 95.6%, 86.9%, 82.6% and 73.9%, respectively. The positive predictive value, calculated on the basis of the presence of each variable alone or in association showed a probability of recanalization of 76.9% for one sign, 84% for two, 96.3% for three and 100% for all four. When we compared the positive predictive values of each variable according to the interval between the beginning of pain and admission to the hospital (during the first 3 hours or between 3 and 6 hours) our results were 100%/94% for pain (P = NS), 97%/88% for arrhythmia (P = NS), 100%/75% for ST segment (P = 0.004), and 97%/80% for enzymes (P = 0.019). The same analysis applied to negative predictive values showing 22%/62% (P = 0.007), 17%/55% (P = 0.008), 21%/47% (P = NS), 27%/61% (P = NS) for pain, arrhythmia, ST segment and enzymes, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)