Sudden death due to smoking?

The increased incidence of sudden death in heart-attack patients who are heavy smokers may be due to ventricular fibrillation, which is enhanced and/or induced by carbon monoxide in the red blood cells.

Using monkeys in a study, DeBias and associates found that when the carbon monoxide level in their blood was elevated to 9 percent, the sensitivity of the heart to induction of fibrillation was significantly enhanced.