ECG of an athlete is many times difficult to interpret. The influence of autonomic tone in athlete’s heart is an complex one.Contrary to our expectations the parasympathetic tone is higher in well trained athletes. The resting heart rate can be as low as 30/mt which is 99.9 times pathological in non athletes.This happens due to a concept called accentuated antagonism.The athletes who have episodic surge of high catecholamines keep stimulating the para sympathetic neurones in a constant fashion.
LVH is the most common feature.Here there is simple myocyte hypertrophy, without pathological fibrosis.This differentiates athlete’s, heart from HOCM .
Many ECG abnormalities are reported in athletes.
Excerpts from the ACC recommendation
1. Electrocardiographic findings that are common and training-related and that do not require additional evaluation are sinus bradycardia, 1° atrioventricular block (AVB), incomplete right bundle branch block (BBB), early repolarization, and isolated voltage criteria for left ventricular hypertrophy (LVH).
2. Uncommon and training unrelated electrocardiographic findings that mandate further evaluation include T-wave inversion, ST-segment depression, pathological Q waves, atrial enlargement, a hemiblock, right ventricular hypertrophy, a BBB, or a Brugada-pattern of ST-segment elevation.
3. Training-related electrocardiographic findings are more common in men than women, athletes of African descent, and high-endurance athletes such as cyclists.
4. Sinus rates <30 bpm and sinus pauses >2 seconds are common in highly trained athletes, particularly during sleep.
5. A normal chronotropic response to exertion and the absence of bradycardia-related symptoms distinguishes training-related sinus bradycardia from sinus node dysfunction.
6. 1° AVB and Mobitz I 2° AVB are common, but Mobitz II 2° AVB or 3° AVB should not be assumed to be training-related and require evaluation.
7. Early repolarization in Caucasian athletes most commonly consists of upwardly concave ST-segments and tall and peaked T waves; in black athletes, there often is convex ST-segment elevation and negative T waves, mimicking a Brugada pattern.
8. In the presence of voltage criteria for LVH, pathological hypertrophy should be suspected if there is left atrial enlargement, left-axis deviation, repolarization abnormalities, or pathological Q waves.
9. T-wave inversion ≥2 mm in ≥2 adjacent leads should prompt evaluation for structural heart disease.
10. Electrophysiological testing for risk stratification with possible catheter ablation is appropriate in athletes with ventricular pre-excitation.
Source : Fred Morady, M.D., F.A.C.C.
http://www.ncbi.nlm.nih.gov/pubmed/19933514?dopt=Abstract
For an excellent article on the topic click here
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