ECG Review-Clearance for Surgery?
March 1, 2000 2 minutes read
ECG Review-Clearance for Surgery?
By Ken Grauer, MD
Clinical Scenario: The ECG shown in the figure was obtained from a 78-year-old man as part of his routine preoperative clearance evaluation. The patient had a history of ischemic heart disease and heart failure. He was on multiple medications. He was completely asymptomatic at the time this ECG was recorded. Would you clear him for surgery?
Interpretation: The rhythm is regular at a rate of between 55 and 60 beats/min. Notable for its absence is the lack of an upright P wave in lead II. Given that the QRS complex is narrow, this defines the rhythm as junctional. The small amplitude upright deflection in lead V1 may represent a retrograde P wave, albeit with a prolonged R-P interval. Otherwise, the axis is vertical, there is evidence of prior anterolateral infarction, and diffuse ST segment and T wave flattening is seen. However, there are no acute changes.
In view of the fact that the patient has underlying heart disease, one has to inquire if digoxin is among the multiple medications he is taking. In point of fact, this patient’s serum digoxin level was in the toxic range.
Digoxin toxicity is notorious for producing a variety of cardiac arrhythmias, especially accelerated junctional rhythms. The presence of an underlying conduction disorder in this patient may have accounted for the relatively slow rate of this digitalis-induced arrhythmia. The patient’s operation should be delayed until his digoxin level returns to the therapeutic range.
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