Influence of heavy cigarette smoking on heart rate variability and heart rate turbulence parameters.
BACKGROUND
Cigarette smoking increases the risk of cardiovascular events related with several mechanisms. The most suggested mechanism is increased activity of sympathetic nervous system. Heart rate variability (HRV) and heart rate turbulence (HRT) has been shown to be independent and powerful predictors of mortality in a specific group of cardiac patients. The goal of this study was to assess the effect of heavy cigarette smoking on cardiac autonomic function using HRV and HRT analyses.


METHODS
Heavy cigarette smoking was defined as more than 20 cigarettes smoked per day. Heavy cigarette smokers, 69 subjects and nonsmokers 74 subjects (control group) were enrolled in this study. HRV and HRT analyses [turbulence onset (TO) and turbulence slope (TS)] were assessed from 24-hour Holter recordings.


RESULTS
The values of TO were significantly higher in heavy cigarette smokers than control group (-1.150 +/- 4.007 vs -2.454 +/- 2.796, P = 0.025, respectively), but values of TS were not statistically different between two groups (10.352 +/- 7.670 vs 9.613 +/- 7.245, P = 0.555, respectively). Also, the number of patients who had abnormal TO was significantly higher in heavy cigarette smokers than control group (23 vs 10, P = 0.006). TO was correlated with the number of cigarettes smoked per day (r = 0.235, P = 0.004). While LF and LF/HF ratio were significantly higher, standard deviation of all NN intervals (SDNN), standard deviation of the 5-minute mean RR intervals (SDANN), root mean square of successive differences (RMSSD), and high-frequency (HF) values were significantly lower in heavy smokers. While, there was significant correlation between TO and SDNN, SDANN, RMSSD, LF, and high frequency (HF), only HF was correlated with TS.


CONCLUSIONS
Heavy cigarette smoking has negative effect on autonomic function. HRT is an appropriate noninvasive method to evaluate the effect of cigarette on autonomic function. Simultaneous abnormal HRT and HRV values may explain increased cardiovascular event risk in heavy cigarette smokers.
Department of Cardiology, Ministry of Health Dişkapi Yildirim Beyazit Research and Educational Hospital, Ankara, Turkey.
Goksel
G
Cagirci
Serkan
S
Cay
Ozlem
O
Karakurt
Neslihan
N
Eryasar
Veli
V
Kaya
Aytun
A
Canga
Asuman Bicer
AB
Yesilay
Harun
H
Kilic
Serkan
S
Topaloglu
Dursun
D
Aras
Ahmet Duran
AD
Demir
Ramazan
R
Akdemir
D000328:Adult; D001341:Autonomic Nervous System / Q000503:physiopathology*; D001342:Autonomic Nervous System Diseases / Q000209:etiology; D015992:Body Mass Index; D015716:Electrocardiography, Ambulatory / Q000379:methods / Q000706:statistics & numerical data; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D012907:Smoking / Q000009:adverse effects / Q000503:physiopathology*