title: Acute effects of smoking on QT dispersion in healthy males.
abstract: BACKGROUND
  Cigarette smoking increases the risk of ventricular fibrillation and sudden cardiac death (SCD). QT dispersion (QTD) is an important predictor of cardiac arrhythmia. The aim of this study was to assess the acute effect of smoking a single standard cigarette containing 1.7 mg nicotine on QT interval and QTD in healthy smokers and nonsmokers.
  
  
  METHODS
  The study sample population consisted of 40 healthy male hospital staff, including 20 smokers and 20 nonsmokers. They were asked to refrain from smoking at least 6 h before attending the study. A 12-lead surface electrocardiogram (ECG), recorded at paper speed of 50 mm/s, was obtained from all participants before and 10 min after smoking of a single complete cigarette. QT interval, corrected QT interval, QTD, and corrected QT dispersion (QTcD) were measured before and after smoking.
  
  
  RESULTS
  Smokers and nonsmokers did not have any significant differences in heart rate (HR) (before smoking = 67.35 ± 5.14 vs. 67.70 ± 5.07, after smoking = 76.70 ± 6.50 vs. 76.85 ± 6.50, respectively), QTD (before smoking = 37.75 ± 7.16 vs. 39.15 ± 6.55, after smoking = 44.75 ± 11.97 vs. 45.50 ± 9.58, respectively), and QTcD (before smoking = 39.85 ± 7.40 vs. 41.55 ± 6.57, after smoking = 50.70 ± 14.31 vs. 51.50 ± 11.71, respectively). However, after smoking a single cigarette, HR, mean QTD, and QTcD significantly increased (all had P value <0.001) in comparison to the measures before smoking.
  
  
  CONCLUSIONS
  Smoking of a single complete cigarette in both smokers and nonsmokers results in significant QTD increase, which can cause arrhythmia and SCD.
authors.affiliation: Assistant Professor, Department of Cardiology, Taleghani Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Mohammad Ali
authors.initials: MA
authors.lastname: Akbarzadeh
authors.affiliation: Cardiologist, Department of Cardiology, Taleghani Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Shahrooz
authors.initials: S
authors.lastname: Yazdani
authors.affiliation: Associate Professor, Department of Cardiology, Taleghani Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Mohamad Esmail
authors.initials: ME
authors.lastname: Ghaidari
authors.affiliation: Associate Professor, Department of Cardiology, Taleghani Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Asadpour-Piranfar
authors.affiliation: General Practitioner, Cardiac Electrophysiology Research Center, Rajaie Cardiovascular Medical & Research Center, Iran University of Medical Sciences, Tehran, Iran.
authors.forename: Negar
authors.initials: N
authors.lastname: Bahrololoumi-Bafruee
authors.affiliation: Cardiologist, Fellowship of Interventional Electrophysiology, Shaheed Beheshti Hospital, Kashan University of Medical Sciences, Kashan, Iran.
authors.forename: Allahyar
authors.initials: A
authors.lastname: Golabchi
authors.affiliation: Fellowship of Pacemaker and Invasive Electrophysiology, Department of Electrophysiology AND Shaheed Rajaei Cardiovascular and Medical Research Center, Iran University of Medical Sciences, Tehran, Iran.
authors.forename: Amirhossein
authors.initials: A
authors.lastname: Azhari
keywords: Cardiac; Death; Electrocardiography; Smoking; Sudden