In 30 chronic smoker (12 women and 18 males) with coronary artery disease, the acute effects of single cigarette smoking on the left ventricular diastolic function were evaluated by echocardiography. Mean age of the patients was 54.2± 7.3 years (range: 38 to 68 years). We used simultaneous M-mode echocardiography of the mitral and aortic valves to measure isovolumetric relaxation time. Also, Doppler echocardiography of transmitral blood flow has been recorded to evaluate the left ventricular filling before and just after smoking. After single cigarette smoking (it contains about 3 mg/cig. nicotine), heart rates and mean arterial blood pressures increased significantly (p