Author + information
- Received July 16, 1985
- Revision received October 16, 1985
- Revision received October 31, 1985
- Published online March 1, 1986.
- Youlian Liao, MD*,
- Linda Ann Emidy, DNSc*,
- Alan Dyer, PhD*,
- John S. Hewitt, PhD*,
- Richard B. Shekelle, PhD†,
- Oglesby Paul, MD, FACC‡,
- Ronald Prineas, MD, FACC§ and
- Jeremiah Stamler, MD, FACC*,a
- ↵aAddress for reprints: Jeremiah Stamler, MD, Department of Community Health and Preventive Medicine, Northwestern University Medical School, 303 East Chicago Avenue, Chicago, Illinois 60611.
A cohort of 1,960 white men aged 40 to 56 years without initial apparent heart disease and with 11 years of annual rest electrocardiograms and 20 year mortality data was followed in the Chicago Western Electric Company Study. Incomplete right bundle branch block was found in 134 men (6.8%) at entry. During follow-up, 222 men developed such block, an incidence rate of 13.6%. Left axis deviation of -30° or less was more frequent in men with than in those without incomplete block at entry (8.2 versus 2.4%). Men with left axis deviation also had a higher incidence of incomplete right bundle branch block. Similarly, men developing incomplete block had a significantly greater risk of developing left axis deviation. The associations between incomplete block and left axis deviation were unrelated to age and body weight.
Men with incomplete block had a significantly greater likelihood of developing complete right bundle branch block. The I1 year incidence rate of complete block was 5.1% for men with baseline incomplete block and 0.7% for those without. Complete block developed in 2 of 220 incident cases of incomplete block but in none of the 440 control men matched by age and duration of follow-up. Although incomplete right bundle branch block was not related to an increased risk of death in 20 years from coronary heart disease and cardiovascular diseases, the study data suggest that such block is frequently a manifestation of primary abnormality of the cardiac conduction system in middle-aged men.
- Received July 16, 1985.
- Revision received October 16, 1985.
- Revision received October 31, 1985.
- American College of Cardiology Foundation