Effects of smoking and inhalation of carbon monoxide on systolic time intervals and blood pressure. Differences between two types of cigarettes and a cigar.

The effects of smoking and inhalation of carbon monoxide on the systolic time intervals and blood pressure were examined in ten healthy smokers with a mean age of 24.3 years. Each subject smoked a low-nicotine cigarette with a ventilated filter (0.1 mg nicotine, 1.1 vol percent CO), and a high-nicotine plain cigarette (2.6 mg nicotine, 4.5 vol percent CO), as well as a cigar in random sequence and in a standardized way. Cigar smoke was not inhaled. The product heart rate x blood pressure was increased and the left ventricular ejection time index (LVETc) prolonged following smoking the high-nicotine cigarette, whereas changes after smoking the low-nicotine cigarette and the cigar were not as pronounced. These changes are presumably caused by nicotine-induced catecholamine release. Inhalation of CO did not affect cardiac performance acutely as shown by unchanged systolic time intervals. When a high-nicotine cigarette was smoked after the subject received a beta blocker, a significant prolongation of the pre-ejection period index (PEPc) occurred as a result of the increased afterload. Thus, the effects of catecholamines on parameters of myocardial contractility (PEPc, PEP/LVET) were presumably offset by the increased afterload. We conclude that the acute hemodynamic changes of smoking in healthy subjects depend upon the amount of nicotine absorbed.