Abstract 4142500: Intrauterine Tobacco Smoke Exposure Affects Cardiac Geometry and Function in Infants

Background: Environmental tobacco smoke (ETS) exposure is associated with increased risk of cardiovascular events, however, there is little information on when cardiovascular functional changes begin to occur. The purpose of this study is to assess blood pressure and cardiac function in infants exposed to ETS . Methods: A total of 224 infants aged 4 months, 78 infants who have been exposed to tobacco smoking since intrauterine life and 146 controls without ETS exposure, underwent echocardiographic study. Left atrial anteroposterior diameter, left ventricular end-diastolic volume, ejection fraction, mass, and mass-to-volume ratio were measured. Transmitral peak flow velocities during early and late diastole and mitral annular myocardial velocities during early and late diastole were measured. Left atrial systolic force was calculated. Isovolumic relaxation time and tissue Doppler-derived myocardial performance index were assessed. Effective arterial elastance was estimated by end-systolic pressure/stroke volume index. End-systolic elastance was calculated by a modified single-beat method. Results: Body mass index was similar between the 2 groups (p >0.05). Systolic and diastolic blood pressures were significantly higher in ETS-exposed infants with than in controls (112 ± 10 vs. 109 ± 9 and 63 ± 8 vs 60 ± 8 mmHg, respectively, p <0.05). Compared with controls, left atrial size, left ventricular mass, and mitral annular myocardial velocities during late diastole were significantly higher (1.6 ± 0.16 vs. 1.4 ± 0.20 cm, 13.7 ± 3.1 vs. 12.6 ± 2.9 g, and 8.4 ± 2.2 vs. 7.6 ± 2.0 cm/sec, respectively, p < 0.05) in infants exposed to ETS. Ejection fraction, isovolumic relaxation time, myocardial performance index, end-systolic elastance, and effective arterial elastance did not differ between the 2 groups. Conclusions: The present study indicates that tobacco smoke exposure can adversely affect blood pressure, cardiac geometry, and function even in early infancy. Passive smoking may contribute to the increased prevalence of cardiovascular diseases in later life.