First Degree Heart Block Evaluation
Most often, a first degree heart block is discovered on an electrocardiogram taken for another reason. A person is said to have a first degree heart block when the measurement of the P-R interval on the EKG is slightly prolonged. In first degree heart block the PR interval is longer than 0.20 seconds. This can be measured directly off the EKG.
There are usually no findings on physical examination in a person with first degree heart block.
A healthy person with a first degree heart block rarely requires a cardiac evaluation. Those with cardiac symptoms, a history of heart disease, thyroid problems, or diabetes may require further testing.
Tests that may be used to evaluate first degree heart block include:
- Electrocardiogram or EKG:
- In first degree heart block the PR interval is longer than 0.20 seconds. This can be measured directly off the EKG.
- This test that can show the heart rhythm, rate, and signs of heart attack.
- EKG machine
- Normal EKG tracing
- Uses sound waves to form images of the inside of the heart.
- Holter monitor:
- Kidney profile
- Cardiac enzymes:
- Chest x-ray:
- Thallium heart scan
- Cardiac stress test:
- Cardiac catheterization:
- Dye is introduced into the coronary arteries, and the blood flow is observed on x-ray.
- Intracardiac electrophysiologic studies (EPS):
- The heart is stimulated with tiny electrical currents in order to find the cause of an arrhythmia.
Continue to First Degree Heart Block Treatment
- Bevilacqua LM, Berul CI. Advances in pediatric electrophysiology. Curr Opin Pediatr. 2004 Oct;16(5):494-9. 
- Delisle BP, Anson BD, Rajamani S, January CT. Biology of cardiac arrhythmias: ion channel protein trafficking. Circ Res. 2004 Jun 11;94(11):1418-28. 
- Liautaud S, Khan AJ, Nalamasu SR, Tan IJ, Onwuanyi AE. Variable atrioventricular block in systemic lupus erythematosus. Clin Rheumatol. 2005 Apr;24(2):162-5. 
- Nagi KS, Joshi R, Thakur RK. Cardiac manifestations of Lyme disease: a review. Can J Cardiol. 1996 May;12(5):503-6.