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Figure. ECG obtained from a 62-year-old man who was seen in an ambulatory care setting.
Clinical Scenario. This ECG generated a computerized interpretation of "sinus bradycardia—otherwise normal ECG." Do you agree with this interpretation?
Interpretation. The rhythm is sinus bradycardia at a rate of 50 beats/minute. The mean QRS axis and all intervals are normal. QRS amplitude is relatively decreased in the standard limb leads. Transition is normal and occurs between leads V2 and V3. There is no sign of chamber enlargement. The most remarkable finding is the presence of tall peaked T waves in most precordial leads. In addition, the ST segment is distinctly flat in leads V4 through V6, instead of manifesting the normal smooth upslope with gradual transition into the T wave (as seen in leads V2 and V3).
Although hyperkalemia is clearly suggested by T wave appearance in this tracing, serum potassium was not increased. Other than hyperkalemia, T wave peaking in anterior precordial leads may be seen as a normal variant or as a manifestation of myocardial ischemia.
Anterior leads typically reflect a mirror image view of ischemic events that occur in the posterior wall. The "mirror image" view of T wave peaking would be deep symmetric T wave inversion, or a pattern suggestive of ischemia. In support of the interpretation that T wave peaking in anterior precordial leads might reflect posterior ischemia is the finding of ST segment flattening in lateral precordial leads. Such ST flattening may be a subtle sign of coronary artery disease. Clinical correlation would be needed in this case to determine the relevance of these subtle but suggestive ECG signs of potential ischemic heart disease.