Objective: 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+/-0.7 mm; C=3.5+/-0.6 mm; P<0.05), and greater left ventricular diastolic (S=7.9+/-0.7 mm; C=7.2+/-0.5 mm; P<0.05) and systolic (S=4.1+/-0.5; C=3.4+/-0.5; P<0.05) diameters. The left ventricular mass index was greater in the smoking animals (S=1.5 mg/kg+/-0.2; C=1.3 mg/kg+/-0.2; P<0.05), and the ejection fraction (S=0.85+/-0.03; C=0.89+/-0.03; P<0.05) and the shortening fraction (S=47.8%+/-3.7; C=52.7%+/-4.6; P<0.05) were greater in the control group. No differences were observed in the diastolic transmitral flow variables (E wave, A wave, and E/A ratio).
Conclusion: Chronic cigarette smoke exposure results in cardiac remodeling with a decrease in ventricular functional capacity.