Abnormal stress test result in 35 year old male

Hello ~

My husband (35 years old) had a nuclear stress test about a week ago.  The scan results state no signs of ischemia or scarring, BUT the EKG portion of the treadmill test came back abnormal and states that there was ST segment depression in lead III from level 2 all the way into level 5 that disappears completely in the post-exercise period.  Impressions were “asymptomatic ischemic response in a well-conditioned individual.”  He was able to achieve 15.2 METS and met 99% of the target heart rate with only mild fatigue and shortness of breath at peak exercise.

The doctor explained that most of the time when the EKG comes back abnormal but the scan is normal that everything is fine, but he referred my husband to a cardiologist to be safe.

My husband is very physicially fit.  He runs 10 miles per day and completed a marathon back in May.  He works out very regularly with weights, eats well, doesn’t smoke (quit back in 2004), no hypertension/diabetes, and does not have any family history of coronary artery disease that we know of.  He also had an echocardiogram and the results of that were perfect.  I will add that my husband had a very severe injury at work about a month ago and has been diagnosed with posttraumatic stress recently.  

How likely is it that this is a false positive?  Is there anything else other than ischemia that can cause this type of result?  

Thank you!

[kenkeith]

For insight, an exercise capacity of 5 METs or less is associated with a poor prognosis in patients younger than 65 years. Exercise capacity of 10 METs signifies a prognosis with medical therapy similar to that of coronary artery bypass surgery. An exercise capacity of 13 METs indicates a good prognosis despite abnormal exercise test responses
Electrocardiographic responses

ST-segment depression: Standard criterion for this response is horizontal or down-sloping ST-segment depression of 0.1 mV or more for 80 milliseconds. The probability and severity of coronary artery disease is related directly to the amount of depression and to the down-slope of the ST segment. Severity of coronary artery disease and prognosis is correlated with the lower workload at which ST-segment depression occurs.
Causes of ST Depression: Worst case scenario would be ischemia (lack of blood flow) to heart cells (usually some occlusion of vessels), electrolytic imbalance, tachycardia (fast heart rate) over 100 at rest, ventricular hypertrophy (pathologically enlarged heart), etc. and it would measure  2 mm beyond QRS.  

Electrocardiographic ST-segment changes are common in patients with an enlarged heart (ventricular hypertrophy) and a well-conditioned individual has a non-pathologically enlarged heart. That would be my first impression, and there can be an insignificant artefact or variant that is caused by noise (stray signal) within the electrical system.  If your husband has a resting heart rate of less than 60 bpm, that would indicate an athlete's heart that is very efficient as a strong contraction requires fewer heart beats to meet the system's demand for blood/oxygen.

As your doctor states there many false positives and an EKG requires further clinical evidence, signs and symptoms.

[Samm1991]

Thank you so much for that information!  By good prognosis, do you mean that since he reached 15.2 METS that there's not much chance of him having heart disease or that if he does he has a better prognosis?

An ST segment depression of 0.9 mm began at level 2 in lead III.  By level 4, the depression was 2.5 in the inferior leads, especially in lead III, and this 2.5 depression persisted into level 5 of up to 2.5 mm.  In the immediate recovery period, it lessened to 1.5 to 2 mm and then completely resolved in the post exercise period.

What is so confusing is that the pictures part of the nuclear test were perfectly normal showing no signs of ischemia at all, so we are hoping the EKG findings were a false positive.

Thank you again!