Assuntos
Humanos , Masculino , Idoso , Estenose da Valva Aórtica/radioterapia , Estenose da Valva Aórtica/diagnóstico por imagem , Prognóstico , Amiloidose/diagnóstico por imagem , Terapêutica/métodos , Imageamento por Ressonância Magnética/instrumentação , Espectroscopia de Ressonância Magnética/métodos , Edema Cardíaco/diagnóstico por imagem , Gadolínio/administração & dosagemAssuntos
Edema Cardíaco/diagnóstico por imagem , Infecções por HIV/epidemiologia , Imageamento por Ressonância Magnética , Miocardite/diagnóstico por imagem , Adulto , Estudos de Casos e Controles , Edema Cardíaco/epidemiologia , Feminino , Infecções por HIV/diagnóstico , Humanos , Masculino , Miocardite/epidemiologia , Peru/epidemiologia , Valor Preditivo dos Testes , Prevalência , Estudos ProspectivosRESUMO
BACKGROUND: Ventricle retraining with abrupt systolic overload can cause myocardial edema and necrosis, followed by late ventricular failure. Intermittent systolic overload could minimize the inadequacy of conventional pulmonary artery banding. The present study compared ventricle function under dobutamine stress in 2 protocols of systolic overload in young goats. METHODS: Nineteen young goats were divided into 3 groups: sham (n = 7; no systolic pressure overload), continuous (n = 6; systolic overload maintained for 96 hours), and intermittent (n = 6; 4 periods of 12-hour systolic overload, paired with a 12-hour resting period). Echocardiographic and hemodynamic evaluations were performed daily. The myocardial performance index and ejection fraction were evaluated at rest and during dobutamine stress. The goats were then killed for morphologic evaluation. RESULTS: The intermittent group underwent less systolic overload than the continuous group (P < .05). Nevertheless, both groups had increased right ventricular and septal masses compared with the sham group (P < .0002). Echocardiography revealed a major increase in right ventricular wall thickness in the intermittent group (+64.8% ± 23.37%) compared with the continuous group (+43.9% ± 19.26%; P = .015). Only the continuous group remained with significant right ventricular dilation throughout the protocol (P < .001). The intermittent group had a significantly better myocardial performance index at the end of the protocol, under resting and dobutamine infusion, compared with the continuous group (P < .012). CONCLUSIONS: Both systolic overload protocols have induced rapid right ventricular hypertrophy. However, only the intermittent group had better preservation of right ventricular function at the end of the protocol, both at rest and during dobutamine infusion.