This retired 73-year-old lawyer has been referred to the cardiac clinic by his family doctor because his ECG (that was normal one year ago) has changed. He has been on an anti-hypertensive medication for 10 years, and his blood pressure has been well controlled. He is normally active and apparently well:

• Sinus rhythm, 95/min
• Right bundle branch block

Right bundle branch block may be found in both cardiac patients and in asymptomatic individuals without evidence of organic heart disease. Its incidence increases with age, which suggests that in older subjects it may be due to slowly progressive degenerative cardiac changes.