Smoking-associated Electrocardiographic Abnormalities Predict Cardiovascular Mortality: Insights from NHANES

Area of Science:

• Cardiology
• Electrophysiology
• Public Health

Background:

• Smoking is linked to cardiac arrhythmias and sudden cardiac death, but underlying mechanisms are unclear.
• Abnormal electrocardiogram (ECG) durations, including QT, P wave, and PR intervals, are known predictors of cardiac events and mortality.

Approach:

• Utilized data from 5,633 adults in the NHANES III study to analyze associations between serum cotinine levels (a marker for smoking) and various ECG interval abnormalities.
• Employed survey-weighted multinomial logistic regression to compare short or long ECG intervals against a reference range in smokers versus non-smokers.
• Conducted linear regression with continuous cotinine levels to assess broader ECG effects and analyzed long-term mortality over 22 years.

Key Points:

• Smoking was associated with increased odds of short PR interval, PR segment, and QRS duration, and a long JT interval.
• Higher cotinine levels showed an inverse association with PR segment and rate-corrected QT (QTc) intervals.
• Several ECG abnormalities, including long JT, QRS, and QTc, and short QRS, predicted cardiovascular mortality in smokers during follow-up.

Conclusions:

• Smoking promotes rapid atrioventricular conduction, rapid ventricular depolarization, and slow ventricular repolarization.
• Electrophysiological abnormalities from smoking predict cardiovascular mortality, but traditional ECG risk markers like QTc may not capture these specific ventricular defects in smokers.