Interpret the ECG shown in Figure 1 — obtained from a middle-aged adult.
- Are there DeWinter T waves in the chest leads of Figure-1? Is this patient about to occlude his proximal LAD (Left Anterior Descending) coronary artery?
- OR — Does this patient have hyperkalemia?
- HINT: What is missing (that should never be missing)?
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| Figure 1: ECG obtained from a middle-aged adult. Are these DeWinter T waves? Does the patient have hyperkalemia? NOTE — Enlarge by clicking on Figures — Right-Click to open in a separate window. |
Systematic Interpretation of Figure 1: There is some baseline movement with slight artifact. The overall rhythm is regular — with upright P waves in lead II, so that the rhythm is Sinus Tachycardia. The rate is ~160/minute (the R-R interval is just under 2 large boxes in duration).
- The PR interval is normal — and the QRS complex is narrow. The QT interval is probably normal given the exceedingly rapid heart rate.
- The axis is indeterminate (QRS complexes are nearly isoelectric in virtually all limb leads).
- There is no chamber enlargement.
- There appears to be a Q wave in lead aVL.
- Transition is slightly delayed to between V4-to-V5 (as the point where the R wave becomes taller than the S wave is deep).
- The most remarkable finding on this tracing are the rather tall and peaked T waves, especially in leads V2-thru-V4. In a patient with chest pain — this appearance resembles that of the DeWinter T waves that herald proximal LAD occlusion. There is even suggestion of some J-point ST depression in leads V3,V4 and V5 prior to the steep rise in T wave ascent. In a patient predisposed to hyperkalemia — the T wave peaking seen here should also prompt consideration of this electrolyte disorder.
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QUESTION: What is missing from this presentation?
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ANSWER: No history was given ...
- It turns out that this 12-lead ECG was recorded as part of an exercise stress test on an otherwise healthy and asymptomatic middle-aged man. The purpose of this test was to assess exercise capacity. There was no chest pain — and no history of renal disease or other medical problems.
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The LESSON to Be Learned: ECGs cannot be intelligently interpreted in a vacuum. If told that this patient was having new-onset worrisome chest pain — We would wonder why he is so tachycardic, and we would clearly be concerned that the prominent T wave peaking might be ischemic or a DeWinter T wave equivalent. We would check serum K+ values as part of our evaluation, especially if the patient had any factors potentially predisposing to hyperkalemia.
- T wave peaking as seen here commonly occurs in healthy adults during exercise. This T wave change is transient — and resolves after termination of exercise.
- Rapid-upsloping ST segment depression as seen here in several chest leads is a normal response to exercise.
- This patient had excellent exercise capacity for his age. His exercise test was entirely normal — and he was cleared to perform vigorous aerobic activity. No laboratory testing was done (as none was necessary).
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- For more information — GO TO:
- For review of the Systematic Approach to ECG Interpretation — Check out our ECG Blog #93.
- For review on DeWinter T Waves — Check out our ECG Blog #53.
- For review on Hyperkalemia — Check out our ECG Blog #10.
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