Cholinergic stimulation with pyridostigmine, hemodynamic and echocardiographic analysis in healthy subjects

OBJECTIVE: Growing evidence suggests that sudden death after an acute myocardial infarction (AMI) correlates with autonomic nervous system imbalance. Parasympathomimetic drugs have been tested to reverse these changes. However, their effects on ventricular function need specific evaluation. Our objective was to analyze pyridostigmine's (PYR) effect on hemodynamic and echocardiographic variables of ventricular function. METHODS: Twenty healthy volunteers underwent Doppler echocardiographic evaluations, blood pressure (BP), and heart rate (HR) assessment at rest, before and 120 min after ingestion of 30 mg PYR or placebo, according to a double-blind, placebo-controlled, crossed and randomized protocol, on different days. RESULTS: PYR was well tolerated and did not cause alterations in BP or in ventricular systolic function. A reduction in HR of 10.9±1.3% occurred (p<0,00001). There was an A wave reduction in the mitral flow (p<0.01) and an E/A ratio increase (p<0.001) without changes in the other diastolic function parameters (p>0.05). CONCLUSION: PYR reduces HR and increases E/A ratio, without hemodynamic impairment or ventricular function change.

Paraplegia following intraaortic balloon circulatory assistance

Intraaortic balloon counterpulsation is frequently used in patients experiencing severe ventricular dysfunction following maximal drug therapy. However, even with the improvement of percutaneous insertion techniques, the procedure has always been followed by vascular, infectious, and neurological complications. This article describes a case of paraplegia due to intraaortic balloon counterpulsation in the postoperative period of cardiac surgery.

Heart transplantation in neonates and children. Intermediate-term results

OBJECTIVE: To assess intermediate-term outcome in children who have undergone orthotopic heart transplantation. METHODS: We carried out a longitudinal and prospective study between October '92 and June '99 comprising 20 patients with ages ranging from 12 days to 7 years (mean of 2.8 years). We employed a double immunosuppression protocol with cyclosporine and azathioprine and induction therapy with polyclonal antithymocyte serum. Survival and complications resulting from the immunosuppression protocol were analyzed. RESULTS:The double immunosuppression protocol and the induction therapy with polyclonal antithymocyte serum resulted in an actuarial survival curve of 90% and 78.2% at 1 and 6 years, respectively, with a mean follow-up period of 3.6 years. One patient died due to acute rejection 40 days after transplantation; another patient died 2 years after transplantation due to lymphoproliferative disorder; a third patient died because of primary failure of the graft; and a fourth patient died due to bronchopneumonia. The major complications were as follows: acute rejection, infection, nephrotoxicity, and systemic hypertension. The means of rejection and infection episodes per patient were 2.9 and 3.4, respectively. After one year of transplantation, a slight reduction in the creatinine clearance and systemic hypertension were observed in 7 (38.9%) patients. CONCLUSION: Heart transplantation made life possible for those patients with complex congenital heart diseases and cardiomyopathies in refractory congestive heart failure constituting a therapeutical option for this group of patients in the terminal phase.

Effects of chlorthalidone and diltiazem on myocardial ischemia in elderly patients with hypertension and coronary artery disease

OBJETIVE: Antihypertensive therapy with thiazides decreases coronary events in elderly patients. However, the influence of diuretics on myocardial ischemia has not been fully investigated. The aim of this study was to compare the effect of chlorthalidone and diltiazem on myocardial ischemia. METHODS: Following a randomized, double-blind, crossover protocol, we studied 15 elderly hypertensive patients aged 73.6±4.6 years with myocardial ischemia. All patients had angiographically documented coronary artery disease. We measured patients using 48- hour ambulatory electrocardiogram monitoring and exercise testing. After a 2-week period using placebo, patients received chlorthalidone or diltiazem for 4 weeks. RESULTS: Both treatments lowered systolic and diastolic blood pressures. The number of ischemic episodes on ambulatory electrocardiogram recordings was reduced with the use of chlorthalidone (2.5±3.8) and diltiazem (3.2±4.2) when compared with placebo (7.9±8.8; p<0.05). The total duration of ischemic episodes was reduced in both treatments when compared with placebo (chlorthalidone: 19.2±31.9min; diltiazem: 19.3±29.6min; placebo: 46.1±55.3min; p<0.05). CONCLUSION: In elderly hypertensive patients with coronary artery disease, chlorthalidone reduced myocardial ischemia similarly to diltiazem. This result is consistent with epidemiological studies and suggests that reduction of arterial blood pressure with thiazide therapy plays an important role in decreasing myocardial ischemia.

Relation between the behaviors of P-wave and QT dispersions in elderly patients with heart failure

OBJECTIVE: To assess the relation between P-wave and QT dispersions in elderly patients with heart failure. METHODS: Forty-seven elderly patients (75.6±6 years) with stable heart failure in NYHA functional classes II or III and with ejection fractions of 37±6% underwent body surface mapping to analyze P-wave and QT dispersions. The degree of correlation between P-wave and QT dispersions was assessed, and P-wave dispersion values in patients with QT dispersion greater than and smaller than 100 ms were compared. RESULTS: The mean values of P-wave and QT dispersions were 54±14 ms and 68±27 ms, respectively. The correlation between the 2 variables was R=0.41 (p=0.04). In patients with QT dispersion values > 100 ms, P-wave dispersion was significantly greater than in those with QT dispersion values < 100 ms (58±16 vs 53±12 ms, p=0.04 ). CONCLUSION: Our results suggest that, in elderly patients with heart failure, a correlation between the values of P-wave and QT dispersions exists. These findings may have etiopathogenic, pathophysiologic, prognostic, and therapeutic implications, which should be investigated in other studies.

Doppler tissue imaging to assess systolic function in Chagas' disease

OBJECTIVE: To assess the usefulness of Doppler tissue imaging (DTI) for evaluating the systolic function of chagasic patients with and without electrocardiographic abnormalities, in comparision with echocardiographic study. METHODS: We studied 77 patients divided into 3 groups as follows: group 1 - control; group 2 - chagasic patients with normal electrocardiographic findings; and group 3 - chagasic patients with abnormal electrocardiographic findings. The following parameters were assessed: left ventricular dimensions and ejection fraction, left atrial dimensions and diastolic function on echocardiography. Systolic velocity and regional isovolumic contraction time (IVCTr) of the septal, anterior, lateral, posterior and inferior left ventricular walls were assessed on DTI. RESULTS: Left ventricular cavitary dimensions, ejection fraction and DTI systolic wave showed significant differences between groups 1 and 3 and between groups 2 and 3, which were not found between groups 1 and 2. IVCTr allowed a statistically significant discrimination among the 3 groups. CONCLUSION: DTI allowed discrimination among the different groups assessed, being superior to echocardiography in identifying early abnormalities of contractility, and, therefore, potentially useful for detecting incipient myocardial alterations in chagasic patients with normal electrocardiographic findings.

Value of the radiological study of the thorax for diagnosing left ventricular dysfunction in Chagas' disease

OBJECTIVE: To determine the value of the radiological study of the thorax for diagnosing left ventricular dilation and left ventricular systolic dysfunction in patients with Chagas' disease. METHODS: A cross-sectional study of 166 consecutive patients with Chagas' disease and no other associated diseases. The patients underwent cardiac assessment with chest radiography and Doppler echocardiography. Sensitivity, specificity, and positive and negative predictive values of chest radiography were calculated to detect left ventricular dysfunction and the accuracy of the cardiothoracic ratio in the diagnosis of left ventricular dysfunction with the area below the ROC curve. The cardiothoracic ratio was correlated with the left ventricular ejection fraction and the left ventricular diastolic diameter. RESULTS: The abnormal chest radiogram had a sensitivity of 50%, specificity of 80.5%, and positive and negative predictive values of 51.2% and 79.8%, respectively, in the diagnosis of left ventricular dysfunction. The cardiothoracic ratio showed a weak correlation with left ventricular ejection fraction (r=-0.23) and left ventricular diastolic diameter (r=0.30). The area calculated under the ROC curve was 0.734. CONCLUSION: The radiological study of the thorax is not an accurate indicator of left ventricular dysfunction; its use as a screening method to initially approach the patient with Chagas' disease should be reevaluated.

Assessment of factors that influence weaning from long-term mechanical ventilation after cardiac surgery

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.

Regional myocardial function in healthy adults: assessment through tissue Doppler echocardiography

OBJECTIVE: To characterize left ventricular regional myocardial function through tissue Doppler echocardiography in healthy adults and to assess the influence of aging in this function. METHODS: In 45 healthy volunteers divided in two groups (< 45 and > 45 years old) we assessed longitudinal and radial regional function (velocities, times intervals and velocity-time integrals). Data were compared in each group and between groups. RESULTS: Systolic function: a) longitudinal: higher velocities and integrals in lateral and inferior walls and in basal segments, with a trend to reduction of these parameters with aging; b) radial: higher basal velocities, no significant change with aging. Diastolic function: a) longitudinal: higher velocities in lateral and inferior walls and in basal segments. With aging e and e/a velocities and integrals decreased, a increased and older individuals showed lower percentage of segments with e/a >1; b) radial: aging was associated with lower e and higher a velocities. CONCLUSION: 1) Tissue Doppler echocardiography detects physiological differences between regional myocardial function of different ventricular segments, in velocities, times intervals and integrals, with physiological heterogeneity and asynchrony; 2) Many of these data are age dependent; 3) Our data contribute to define normal values, and may become useful when compared with data from populations with heart diseases.

Associação entre evolução da função cognitiva e mortalidade após a alta hospitalar em pacientes idosos com insuficiência cardíaca avançada

OBJETIVO: Avaliar a associação entre a evolução do desempenho cognitivo e o prognóstico de idosos após compensação de insuficiência cardíaca avançada. MÉTODOS: Selecionados, consecutivamente, 31 pacientes internados com insuficiência cardíaca classe IV da New York Heart Association, com idade > 64 anos (68 ±7) e fração de ejeção < 0,45 (0,38 ± 0,06). Submetidos a testes cognitivos (digit span, digit symbol, letter cancellation, trail making A e B) e teste de caminhada de 6min, 4 dias antes da alta (T1) e 6 semanas após (T2), cujos desempenhos foram comparados pelo teste T. O valor prognóstico dos escores dos testes cognitivos foram analisados pela regressão logística e o valor de maior acurácia dos testes associado com o prognóstico determinado pela ROC curve. RESULTADOS: Após 24,7 meses, 17 (55%) pacientes faleceram. Os desempenhos ao teste de caminhada e maioria dos testes cognitivos melhoraram entre T1 e T2. O escore do digit span entre os sobreviventes variou de 3,9 para 5,2 (p=0,003), permanecendo inalterado entre os que faleceram (4,1para 3,9; p=0,496). Melhora < 0,75 pontos no escore foi associada à mortalidade (risco relativo de 8,1; p=0,011). CONCLUSÃO: Em idosos, após a compensação de insuficiência cardíaca avançada, a ausência de melhora evolutiva do desempenho cognitivo foi associada a pior prognóstico.

Estratégia para individualizar uma dose eficiente de betabloqueador em pacientes idosos com isquemia miocárdica e função ventricular esquerda preservada

OBJETIVO: Avaliar estratégia de titulação para prescrever uma dose de propranolol que seria eficiente em reduzir isquemia do miocárdio em idosos. MÉTODOS: Foram estudados 14 homens idosos (73,6 ± 5,3 anos), portadores de doença coronariana estável, documentada pela cinecoronariografia, com resposta isquêmica ao teste ergométrico e função ventricular esquerda preservada. O propranolol foi titulado a fim de atingir redução de 15% na freqüência cardíaca, ao final da carga de 50 W (correspondente às atividades diárias normais de idosos), em testes ergométricos semanais e feito estudo cintilográfico sincronizado das câmaras cardíacas, em repouso e durante exercício, antes e após seu uso. RESULTADOS: As reduções da freqüência cardíaca na carga de 50 W e em repouso foram semelhantes (21% vs 20%; p=0,5100). O propranolol melhorou a duração do exercício (12,2 ± 2,0 min vs 13,1 ± 1,8 min; p=0,0313) e aboliu as alterações do segmento ST induzidas pelo exercício em 8 (57%) pacientes. Em repouso, a fração de ejeção não foi modificada pelo betabloqueador. Durante o exercício máximo, o propranolol reduziu o índice de volume sistólico final e aumentou a fração de ejeção. CONCLUSÃO: A estratégia de empregar betabloqueadores para reduzir a freqüência cardíaca em 15% na carga de 50 W é segura e benéfica nos idosos com isquemia miocárdica e função ventricular preservada. A dose utilizada reduziu a isquemia miocárdica e melhorou a tolerância ao exercício, sem prejudicar o desempenho ventricular durante exercício máximo.

Estresse ortostático ativo e arritmia sinusal respiratória em chagásicos com função sistólica global do ventrículo esquerdo preservada

OBJETIVO: Avaliar a utilização do teste de estresse ostostático ativo na detecção de disfunção vagal em chagásicos com função sistólica global preservada, comparando-o ao teste da arritmia sinusal respiratória. MÉTODO: Foram selecionados 61 chagásicos (Ch) e 38 não-chagásicos (NCh) sem evidências significativas de cardiopatia ou doenças sistêmicas, submetidos ao ecodopplercardiograma e às provas autonômicas. O teste da arritmia sinusal respiratória foi realizado através do registro eletrocardiográfico enquanto o paciente respirava profundamente, a 6 irpm, calculando-se a razão E:I (média das razões entre os maiores intervalos RR expiratórios e os menores RR inspiratórios a cada ciclo). O eletrocardiograma foi registrado enquanto o paciente se levantava e nos 30s seguintes (teste do estresse ortostático ativo), calculando-se a razão RR máx./RR min (maior e menor intervalo RR logo após a mudança postural). Os índices foram ajustados para covariáveis significativas. RESULTADOS: A razão RR max:min (NCh: 1,52 [1,44-1,74] x Ch: 1,43 [1,33-1,51], p < 0,001) e a razão E:I (NCh: 1,38±0,02 x Ch: 1,25±0,02, p<0,001) foram menores entre os chagásicos. Houve elevada correlação entre a razão RR max:min e a razão E:I ajustadas (r = 0,628, p < 0,001), mas ambas não se correlacionaram significativamente com a fração de ejeção do ventrículo esquerdo. CONCLUSÃO: Chagásicos com função sistólica global do ventrículo esquerdo preservada apresentam redução significativa de índices vagais obtidos por provas curtas, quando comparados a controles normais. O teste de estresse ortostático ativo apresentou boa correlação com a manobra de arritmia sinusal respiratória, constituindo-se opção válida na avaliação ambulatorial do controle vagal.