Domingo M BraileI; Marcelo J. F SoaresI; Dorotéia R. S SouzaI; Max SchaldachII
DOI: 10.1590/S0102-76381994000100004
RESUMO
Na cardiomioplastia, a contração do músculo esquelético, submetido à estimulação elétrica sobre a parede ventricular dilatada, aumenta a função ventricular, que é dependente das condições prévias do coração e da doença de base. Um dos problemas principais que interfere no sucesso da substituição do músculo cardíaco é a estimulação sincrónica do miocárdio e o músculo esquelético. A estimulação desse músculo a longo prazo tem sido possível graças a eletrodos especiais associados à estimulação progressiva seqüencial, adaptando-o à função cardíaca, através da transformação gradual de fibras glicolíticas expostas à fadiga em oxidativas lentas altamente resistentes. O gerador de pulsos "Myos" (Biotronik) tem sido utilizado em nosso Serviço para estimulação elétrica do músculo grande dorsal em sincronização com o miocárdio. Esse tipo de cardiomioestimulador com circuito eletrônico e bateria de lítio armazena um programa de estimulação responsável por diferentes modos operacionais, adaptados por um programa de computação. Para a programação do cardiomioestimulador, o momento da sincronização do trem de pulso com a abertura da valva aórtica é de extrema importância. O modo M de alta velocidade é utilizado para avaliar este sincronismo. A avaliação clínica da cardiomioplastia tem como base os resultados obtidos de 32 pacientes, com idade de 22 a 72 anos (média = 46,2 anos). A maioria (72%) dos pacientes apresentou miocardiopatia dilatada por causa indeterminada, 24% de origem chagásica, 3% virótica e 3% por periparto. Os índices de mortalidade hospitalar e tardia foram ambos de 12,5% e de 3,1%, respectivamente, excluindo-se os chagásicos. A sobrevida atuarial foi de 81,3+-0,22% após 6 anos e de 94.4+-0,1 % após 5 anos, retirando-se os chagásicos. Os índices médios de diâmetros sistólico (55,1 mm), diastólico (70,7 mm), encurtamento segmentar (22,8%) e fração de ejeção (51,0%), referentes a seguimento médio de 14,2 meses, refletem que a cardiomioplastia pode ser efetiva na assistência do ventrículo esquerdo. A escolha do paciente parece ser a chave para o bom resultado operatório a curto e longo prazos.ABSTRACT
In the cardiomyoplasty, the contraction of the skeleton muscle, undergone electric stimulation on the dilated ventricle wall, increases the ventricle function, which is dependent of the heart and the base disease previous conditions. One of the main problems which interferes with the sucess of the cardiac muscle replacement is the myocardial synchronic stimulation and the skeleton muscle. The stimulation of this muscle in long-term has been possible because of the special electrodes associated with the sequential progressive stimulation, adjusting it to the cardiac function, through the gradual transformation of glicolitic fibers exposed to fatigue in highly resistant slow oxidizers. The pulse generator Myos (Biotronik) has been used in our center for electrical stimulation of the latissimus dorsalis in synchronization with the myocardium. This electronic circuit and lithium battery type of cardiomyostimulator stores a stimulation program responsible for different operational modes, adapted by acomputer program. In order to program the cardiomyostimulator, the moment of the pulse synchronization with the aortic valve opening is extremely important. The high velocity M mode is utilized to evaluate the synchronism. The cardiomyoplasty clinical evaluation is based on the results obtained from 32 patients at 22 ti 72 years old (average=46.2 years) most of patients (72%) presented dilated myocardiopathy due to undetermined cause, 24% of chagasic origin, 3% virus and 3% due to peripartum. Hospital and late mortality rate were both 12.5% and 3.1% and 3.7% respectively, excluding the chagasic patients. The actuarial survival was 81.3 + - 0.22% after 6 years and 94.4 + - 0.1 % after 5 years, withdrawing the chagasic patients. The average indexes of systolic diameters (55,1 mm), diastolic (70,7 mm), segmental shortening (22.8%) and ejection fraction (51.0%), related to an average follow-up of 14.2 months, reflect that the cardiomyoplasty can be effective to assist the left ventricle. Choosing the right patient seems to be key to the goog operative result in short and long terms.REFERÊNCIAS
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