RESUMO
Cardiac resynchronizing therapy (CRT) is currently a leading approach to the treatment of heart failure in adults. However, data regarding application of CRT in children remain limited and indications for CRT are unclear. There is evidence that the best treatment outcomes result from the administration of CRT to the group of children whose heart failure is caused by dyssynchrony mediated by traditional stimulation of the right ventricle in patient with complete atrioventricular block. On the contrary, the presence of dilated cardiomyopathy and functional class III-IV heart failure are the predictors of ineffective CRT. Implantation of CRT devices in children has many peculiarities and challenges associated with anatomic and physiological characteristics of childhood age. Taking into consideration the expected length of treatment, one should admit that epicardial biventricular stimulation should be preferred. In the present paper the authors discuss pathophysiology of the electromechanical dyssynchrony, analyze their own experience with CRT, and suggest indications for this kind of treatment.
Assuntos
Terapia de Ressincronização Cardíaca/métodos , Insuficiência Cardíaca/terapia , Criança , Humanos , Resultado do TratamentoRESUMO
Cardiac resynchronizing therapy (CRT) is currently a leading approach to the treatment of heart failure in adults. However, data regarding application of CRT in children remain limited and indications for CRT are unclear. There is evidence that the best treatment outcomes result from the administration of CRT to the group of children whose heart failure is caused by dyssynchrony mediated by traditional stimulation of the right ventricle in patient with complete atrioventricular block. On the contrary, the presence of dilated cardiomyopathy and functional class III-IV heart failure are the predictors of ineffective CRT. Implantation of CRT devices in children has many peculiarities and challenges associated with anatomic and physiological characteristics of childhood age. Taking into consideration the expected length of treatment, one should admit that epicardial biventricular stimulation should be preferred. In the present paper the authors discuss pathophysiology of the electromechanical dyssynchrony, analyze their own experience with CRT, and suggest indications for this kind of treatment.
RESUMO
The rhythmoinotropic dependence of the papillary muscles was studied in rats with postinfarction cardiosclerosis after blocking of beta(1)-adrenoreceptors by concor (7 mg/kg daily). The development of postinfarction cardiosclerosis led to a reduction of the postextrasystolic potentiation and of potentiation induced by periods of rest. Preliminary blocking of beta(1)-adrenoreceptors stimulated the postextrasystolic contractions and contractions after periods of rest in the myocardium of rats with postinfarction cardiosclerosis. These results suggest that blocking of beta(1)-adrenoreceptors promotes an improvement of calcium-accumulating function of the cardiomyocyte sarcoplasmatic reticulum in the myocardium of rats with postinfarction cardiosclerosis.
