Acute Effect of Cigarette Smoking on Heart Rate Variability Osman Karakaya, MD,* Irfan Barutcu, MD,* Dayimi Kaya, MD, † Ali Metin Esen, MD,* Mustafa Saglam, MD,* Mehmet Melek, MD, † Ersel Onrat, MD, † Muhsin Turkmen, MD,* Ozlem Batukan Esen, MD, ‡ and Cihangir Kaymaz, MD,* Istanbul and Afyon, Turkey Acute cigarette smoking enhances adrenergic activity and thus may be associated with hemody- namic changes in the cardiovascular system. In this study, the acute effect of cigarette smoking on heart rate variability (HRV) was studied. Fifteen subjects were included in the study. Time domain (the mean R-R interval, the standard deviation of R-R interval, and the root mean square of succes- sive R-R interval differences) and frequency domain (high-frequency, low-frequency ratio, and low-frequency/high-frequency ratio) parameters of HRV were obtained from all participants for each 5-minute segment: 5 minutes before and 5, 10, 15, 20, 25, and 30 minutes after smoking a cigarette. The mean R-R interval, the standard deviation of R-R interval, and the root mean square of successive R-R interval differences significantly decreased within the first 5-minute period compared with baseline, and then the standard deviation of R-R interval increased within the 20- to 30-minute period. The low-frequency high-frequency ratio significantly decreased within the first 5 minutes after smoking and then remained unchanged throughout the study period. Similarly, low- frequency and high-frequency power increased within the first 5 minutes compared with baseline. Acute cigarette smoking alters HRV parameters, particularly within the first 5 to 10 minutes after smoking. Introduction Long-term cigarette smoking is a major and inde- pendent risk factor for cardiovascular morbidity and mortality. Previous reports suggest that chronic smokers have a higher pulse rate and blood pressure compared with nonsmokers, indicating sympathetic hyperactivity. 1-3 It has been shown that cigarette smoking acutely increases plasma catecholamines and cardiac norepinephrine spillover and results in an increase in blood pressure and heart rate and sympathetic outflow. 4 Previous studies have sug- gested the chronic effect of cigarette smoking on heart rate variability (HRV) 5-8 ; however, to our knowledge, the acute effect of cigarette smoking on HRV has not been extensively studied, partic- ularly in nonsmokers. In clinical practice, HRV has been shown to be a valuable noninvasive tool for the assessment of autonomic cardiovascular function. Frequency domain and time domain parameters have been recommended for HRV analysis with 5-minute (short-term) recordings. 9 Reduced HRV pre- dicts ominous clinical outcome in various con- ditions, and it is associated with increased risk Angiology 58:620–624, October/November 2007 From the *Department of Cardiology, Kosuyolu Heart Education and Research Hospital, † Department of Cardiology, Kocatepe University Faculty of Medicine, and ‡ Department of Cardiology, Memorial Hospital, Istanbul and Afyon, Turkey. Correspondence: Osman Karakaya, MD, 19 may¸s mahallesi sar¸kanarya sok, Muhsinbey Apartment Number 25/17- Kozyatag  ¸, Istanbul, Turkey E-mail: drkarakaya@yahoo.com DOI: 10.1177/0003319706294555 ©2007 Sage Publications Angiology Volume 58, Number 5, 2007 620 at Afyon Kocatepe Universitesi on December 24, 2014 ang.sagepub.com Downloaded from