Emprego de altas doses de amiodarona via oral na reversão da fibrilação atrial no pós-operatório de cirurgia cardíaca

OBJETIVO: Relatar a experiência no emprego de altas doses de amiodarona via oral (1800mg/d) na reversão da fibrilação atrial (FA) em pacientes submetidos à cirurgia cardíaca. MÉTODOS: Analisados, retrospectivamente, 80 pacientes que apresentaram FA no pós operatório de cirurgia cardíaca, constituindo 2 grupos: grupo A com 28 pacientes em uso de amiodarona e grupo B recebendo digital, sendo que este grupo foi subdividido no grupo C com 21 pacientes onde foi associada amiodarona, quando não houvesse reversão da arritmia em 48h. As diferenças foram consideradas significativas para um valor de P<0,05. RESULTADOS: A FA esteve presente em 19,4% dos pacientes operados, com predomínio no sexo masculino e entre 60-69 anos. No grupo A, a reversão ocorreu em 78,6% dos casos, grupo B, o digital obteve sucesso em 60% das vezes e no grupo C, a taxa de sucesso foi de 90%. CONCLUSÃO: O uso de altas doses de amiodarona via oral, isolada ou em combinação com digital pode ser segura e eficaz no tratamento da FA em pós operatório de cirurgia cardíaca.

Análise da recorrência de fibrilação atrial durante terapia com sotalol ou quinidina

OBJETIVO: Analisar a incidência e as características das crises de recorrência de fibrilação atrial (FA) em pacientes sob terapia com sotalol ou quinidina. MÉTODOS: Cento e vinte e um pacientes receberam de forma randômica sotalol (58 pacientes) ou quinidina (63 pacientes) após reversão de FA paroxística e foram acompanhados, ambulatorialmente, por 6 meses. As sintomatologias e as freqüências ventriculares ao eletrocardiograma de 12 derivações da crise inicial e da recorrência foram comparadas entre os grupos de drogas. As características clínicas e os dados do ecocardiograma foram analisados como preditores de recorrência. RESULTADOS: Dezessete (14%) pacientes apresentaram recorrência da arritmia, 7 (12%) em uso de sotalol e 10 (16%) em uso de quinidina. A recorrência ocorreu mais tardiamente no grupo tratado com sotalol (mediana de 69 dias) em comparação ao grupo tratado com quinidina (mediana de 10 dias) (p=0,04). A sintomatologia esteve presente em 14 (82%) pacientes na crise inicial e em 8 (47%) pacientes na recorrência. O tratamento antiarrítmico proporcionou recorrências menos sintomáticas (p<0,04), não sendo possível demonstrar diferença significante entre as terapias. Somente os pacientes tratados com sotalol apresentaram menor freqüência ventricular na recorrência em comparação à crise inicial (p<0,02). Todas as variáveis falharam em predizer recorrência da FA. CONCLUSÃO: Não foi possível demonstrar diferença entre o sotalol e a quinidina na prevenção de FA. O tratamento antiarrítmico proporcionou a ocorrência de recorrências menos sintomáticas. Os pacientes tratados com sotalol apresentaram recorrência mais tardiamente e freqüência ventricular significantemente menor na recorrência em comparação à crise inicial.

Ablação por cateter do flutter atrial. Caracterização eletrofisiológica da interrupção da condução pelos istmos posterior e septal

OBJETIVO: Avaliar os tipos de bloqueio obtidos nos istmos posterior (entre o anel tricuspídeo e veia cava inferior) e septal (entre o anel tricuspídeo e óstio do seio coronário), após ablação do flutter atrial (FLA). MÉTODOS: Foram submetidos à ablação por radiofreqüência (RF) 14 pacientes com FLA tipo I (9 homens) em 16 procedimentos. A ativação atrial ao redor do anel tricuspídeo foi avaliada em ritmo sinusal utilizando-se cateter "Halo" com 10 pares de eletrodos (H1-2 a H19-20), durante estimulação do seio coronário proximal (SCP) e região póstero-lateral do átrio direito (H1-2), antes e após ablações lineares. De acordo com a frente de programação do impulso definiu-se: ausência de bloqueio (condução bidirecional), bloqueio incompleto (condução bidirecional com retardo num dos sentidos) e bloqueio completo (ausência de condução pelo istmo). O intervalo desta ativação (deltaSCP/H1-2) foi analisado. RESULTADOS: Bloqueio completo foi obtido em 7 procedimentos (44%) e incompleto em 4 (25%). O deltaSCP/H1-2 foi de 74 ± 26ms no primeiro grupo e de 30,5 ± 7,5ms no segundo (p<0,05). Em 5 casos não demonstrou-se bloqueio. Num seguimento médio de 12 meses, ocorreu recorrência do FLA nos 6 pacientes com bloqueio incompleto ou ausente e em nenhum com bloqueio completo (p<0,001). CONCLUSÃO: A verificação de bloqueio completo pelo mapeamento multipolar atrial é uma estratégia eficaz para definir o sucesso e recorrência clínica na ablação do FLA tipo I.

Mixoma atrial esquerdo com acidente vascular cerebral isquêmico em criança

É apresentado um caso de mixoma atrial esquerdo associado a acidente vascular cerebral embólico em paciente do sexo feminino, com oito anos de idade. Feita a exérese do tumor, a criança apresentava, dois meses após cirurgia, presença de massa septoatrial esquerda, sugerindo recidiva, mantendo-se, porém, assintomática. A revisão da literatura enfatiza a raridade e a agressividade com que este tumor acomete esta faixa etária, além de salientar baixas taxas de recidiva após sua retirada.

Ablação com radiofreqüência do flutter atrial tipo I. Importância do bloqueio bidirecional do istmo entre a veia cava inferior e o anel da valva tricúspide

OBJETIVO: Estudar a importância clínica da determinação eletrofisiológica da presença de bloqueio bidirecional na condução pelo istmo localizado entre a veia cava inferior e o anel da valva tricúspide (VCI - AT), após a ablação do flutter atrial tipo I (FL) com radiofreqüência (RF). MÉTODOS: Quarenta pacientes consecutivos (idade média 51±11 anos) com FL foram submetidos a ablação do istmo VCI-AT com RF. Em 30 pacientes (GI), o sucesso foi avaliado pela interrupção e não reindução do FL com estimulação atrial programada. Nos últimos 10 pacientes foi avaliada também a condução bidirecional pelo istmo, com cateteres posicionados na sua entrada e saída e em cada lado da linha de bloqueio. O bloqueio foi considerado bidirecional quando ocorrido nos dois sentidos e unidirecional quando ocorrido em um só sentido. RESULTADOS: Vinte e seis (86%) pacientes do GI e 10 (100%) do GII tiveram sucesso imediato (p= 0,5558). Durante o seguimento, 7 (30%) de 23 pacientes do GI e 3 (30%) de 9 do GII tiveram recorrência de FL (p= NS). Os três pacientes do GII que apresentaram recorrência tinham bloqueio unidirecional, enquanto os seis casos sem recorrência tinham bloqueio bidirecional (p=0,012). CONCLUSÃO: A demonstração de bloqueio bidirecional no istmo VCI-AT, obtida imediatamente após a ablação do FL com RF, relaciona-se a menor índice de recorrência clínica, devendo ser o critério preferencial para término do procedimento.

Percutaneous closure of atrial septal defects. The role of transesophageal echocardiography

PURPOSE: Evaluation of the role of transesophageal echocardiography in percutaneous closure of atrial septal defects (ASD) with the Amplatzer septal occluder. METHODS: Patients were selected for percutaneous closure of ASD by transesophageal echocardiography (TEE), which was also used to monitor the procedure, helping to select the appropriate size of the Amplatzer device, to verify its position, and to access the immediate results of the procedure. During the follow-up, TEE was used to evaluate the presence and magnitude of residual shunt (RS), device position, and right cardiac chamber diameters. RESULTS: Twenty-two (40%) of a total of 55 studied patients were selected. Thirteen underwent Amplatzer device implantation, eight are still waiting for it, and one preferred the conventional surgical treatment. All procedures were successful, which was mainly due to proper patient selection. Six (23%) patients acutely developed RS, which spontaneously disapeared at the three-month follow-up examination in three patients. There was a significant reduction in the right ventricle diastolic diameter, from 27mm (average) to 24mm and 20mm, one and three months after the procedure, respectively (p<0.0076). CONCLUSION: With the aid of TEE, percutaneous closure of ASD can be successfully, safely, and effectively performed.

Recurrence of atrial septal defect in three generations

Beginning with a patient presenting with an atrial septal defect (ASD) of the secundum type, the genealogy was identified in four affected individuals who belonged to three successive generations of the same family. The defects were visually confirmed in all individuals and were found to be anatomically similar. No other congenital malformations were present in these individuals. The genealogy was identified in 1972, when ASD recurred in two generations, and it was concluded that the mechanism of transmission was autosomal recessive. The fifth individual, identified 21 years later, and having an anomaly identical to that of the others, was the child of a couple who had no consaguinity and whose mother was a member of the previously studied genealogy. Considering the absence of phenotype in the parents and the rarity of the ASD gene in the general population, the occurrence of the uniparental disomy for this family nucleus, and the same autosomal recessive mechanism of transmission by this affected individual is possible. This study reports the familial occurrence of ASD by genetic mechanisms of transmission, emphasizing the necessity for genetic-clinical studies in members of the familial nucleus in order to detect new carriers, who usually are asymptomatic, thereby allowing for early and adequate treatment of individuals who may be affected.

Gas exchange during exercise in different evolutional stages of chronic Chagas' heart disease

OBJECTIVE: To compare gas exchange at rest and during exercise in patients with chronic Chagas' heart disease grouped according to the Los Andes clinical/hemodynamic classification. METHODS: We studied 15 healthy volunteers and 52 patients grouped according to the Los Andes clinical/hemodynamic classification as follows: 17 patients in group IA (normal electrocardiogram/echocardiogram), 9 patients in group IB (normal electrocardiogram and abnormal echocardiogram), 14 patients in group II (abnormal electrocardiogram/echocardiogram, without congestive heart failure), and 12 patients in group III (abnormal electrocardiogram/echocardiogram with congestive heart failure). The following variables were analyzed: oxygen consumption (V O2), carbon dioxide production (V CO2), gas exchange rate (R), inspiratory current volume (V IC), expiratory current volume (V EC), respiratory frequency, minute volume (V E), heart rate (HR), maximum load, O2 pulse, and ventilatory anaerobic threshold (AT). RESULTS: When compared with the healthy group, patients in groups II and III showed significant changes in the following variables: V O2peak, V CO2peak, V ICpeak, V ECpeak, E, HR, and maximum load. Group IA showed significantly better results for these same variables as compared with group III. CONCLUSION: The functional capacity of patients in the initial phase of chronic Chagas' heart disease is higher than that of patients in an advanced phase and shows a decrease that follows the loss in cardiac-hemodynamic performance.

Arterial distensibility as a possible compensatory mechanism in chronic aortic regurgitation

OBJECTIVE: To evaluate elastic properties of conduit arteries in asymptomatic patients who have severe chronic aortic regurgitation. METHODS: Twelve healthy volunteers aged 30±1 years (control group) and 14 asymptomatic patients with severe aortic regurgitation aged 29±2 years and left ventricular ejection fraction of 0.61±0.02 (radioisotope ventriculography) were studied. High-resolution ultrasonography was performed to measure the systolic and diastolic diameters of the common carotid artery. Simultaneous measurement of blood pressure enabled the calculation of arterial compliance and distensibility. RESULTS: No differences were observed between patients with aortic regurgitation and the control group concerning age, sex, body surface, and mean blood pressure. Pulse pressure was significantly higher in the aortic regurgitation group compared with that in the control group (78±3 versus 48±1mmHg, P<0.01). Arterial compliance and distensibility were significantly greater in the aortic regurgitation group compared with that in the control group (11.0±0.8 versus 8.1±0.7 10-10 N-1 m4, P=0.01 e and 39.3±2.6 versus 31.1±2.0 10-6 N-1 m², P=0.02, respectively). CONCLUSION: Patients with chronic aortic regurgitation have increased arterial distensibility. Greater vascular compliance, to lessen the impact of systolic volume ejected into conduit arteries, represents a compensatory mechanism in left ventricular and arterial system coupling.

The impact of syncope during clinical presentation of sustained ventricular tachycardia on total and cardiac mortality in patients with chronic Chagasic heart disease

OBJECTIVE: To assess the impact of syncope during sustained ventricular tachycardia on total and cardiac mortality in patients with chronic chagasic heart disease. METHODS: We assessed 78 patients with sustained ventricular tachycardia and chronic Chagas' heart disease. The mean age was 53±10 years, 45 were males, and the mean ejection fraction was 49.6±13%. The patients were divided into 2 groups according to the presence (GI=45) or absence (GII=33) of syncope during sustained ventricular tachycardia. RESULTS: After a mean follow-up of 49 months, total mortality was 35% (28 deaths), 22 deaths having a cardiac cause (78.6%). No difference was observed in total (33.3% x 39.4%) and cardiac (26.7% x 30.3%) mortality, or in nonfatal sustained ventricular tachycardia between GI and GII patients (57.6% x 54.4%, respectively). However, the presence of syncope during recurrences was significantly greater in those patients who had had the symptom from the beginning (65.4% x 18.1%, p<0.01). CONCLUSION: Syncope during the presentation of sustained ventricular tachycardia is not associated with an increase in total or cardiac mortality in patients with chronic Chagas' heart disease. However, syncope during the recurrence ventricular tachycardia is greater in patients experiencing syncope in the first episode, of sustained ventricular tachycardia.

Fontan Operation and the Cavopulmonary Technique: Immediate and Late Results According to the Presence of Atrial Fenestration

OBJECTIVE: To compare immediate and late results in patients with or without fenestration who underwent cavopulmonary anastomosis so that we could assess the efficiency of the technique. METHODS: Sixty-two patients underwent surgery between 1988 and 1999, 41 with fenestration (group I -G I) and 21 without fenestration (group II -G II). Tricuspid atresia was prevalent in group I (23-56%) and single ventricle was prevalent in group II (14-66%). Mean ages at the time of operation were 7.3 years in group I and 7.6 in group II. At late follow-up, mean ages were 10.6 years in group I and 12.8 years in group II. RESULTS: Immediate and late mortality were 7.3% in G-I and 4.7% in G-II. Significant pleural effusion occurred in 41.4% of G-I patients and in 23.8% of G-II patients. Significant pericardial effusion occurred in 29.2% and 14.2%, respectively, in groups I and II. Central venous pressure was greater in G-II, 17.7 cm in H2O, as opposed to 15 cm in G-I. Hospital stay was similar between the groups, 26.3 and 21.8 days, respectively. Cyanosis and arterial insaturation occurred in 5 patients, and 4 patients were in functional class II, all from G-I. At late follow-up, 58 (93.5%) were in functional class I. Sinus rhythm was present in 94%, and pulmonary perfusion was similar in both groups. Eleven patients who underwent spirometry had good tolerance to physical effort. CONCLUSION: Atrial fenestration did not improve the immediate or late follow-up of patients who underwent cavopulmonary anastomosis, and is, therefore, dispensable.