A exposição crônica à fumaça do cigarro resulta em remodelação cardíaca e prejuízo da função ventricular em ratos Chronic cigarette smoke exposure results in cardiac remodeling and impaired ventricular function in rats

OBJETIVO: Determinar as alterações cardíacas estruturais e funcionais causadas pela exposição à fumaça do cigarro em ratos. MÉTODOS: Os animais foram aleatoriamente distribuídos em dois grupos: fumante (F), composto por 10 animais, expostos à fumaça do cigarro, na taxa de 40 cigarros/dia e controle (C), constituído por 10 animais não submetidos à exposição. Após 4 meses, os animais foram submetidos a estudo morfológico e funcional por meio do ecocardiograma. As variáveis estudadas foram analisadas pelo teste t ou pelo teste de Mann-Whitney. RESULTADOS: Os ratos fumantes apresentaram maior átrio esquerdo (F=4,2&plusmn; 0,7mm; C=3,5&plusmn;0,6mm; pOBJECTIVE: To determine the cardiac structural and functional alterations caused by cigarette smoke exposure in rats. METHODS: The animals were randomly distributed into the following 2 groups: 1) smokers (S), comprising 10 animals exposed to cigarette smoke at a rate of 40 cigarettes/day; and 2) control (C), comprising 10 animals not exposed to cigarette smoke. After 4 months, the animals underwent morphological and functional study with echocardiography. The variables studied were analyzed by use of the t test or the Mann-Whitney test. RESULTS: The smoking rats had a greater left atrium (S=4.2&plusmn;0.7mm; C=3.5&plusmn;0.6mm; P<0.05), and greater left ventricular diastolic (S=7.9&plusmn;0.7mm; C=7.2&plusmn;0.5mm; P<0.05) and systolic (S=4.1&plusmn;0.5; C=3.4&plusmn;0.5; P<0.05) diameters. The left ventricular mass index was greater in the smoking animals (S=1.5mg/kg&plusmn;0.2; C=1.3mg/kg&plusmn;0.2; P<0.05), and the ejection fraction (S=0.85&plusmn;0.03; C=0.89&plusmn;0.03; P<0.05) and the shortening fraction (S=47.8%&plusmn;3.7; C=52.7%&plusmn;4.6; P