QUESTION: Interpret the 12-lead ECG below, obtained from a 45 year old man who presented to the ED with new-onset chest discomfort. He had been previously healthy. Risk factors include a history of smoking. No prior ECG available.
- How would you interpret his ECG? - Any potentially worrisome ECG findings?
- Clinically - What would you do?
Figure 1 (ECG reproduced from our Expanded ECG pdf File)
- Note - Enlarge by clicking on Figures -
- Q-R-S-T Changes: - Small and narrow q waves are seen in a number of leads (II, III, aVF and V6) - and a deep Q wave (QS complex) is seen in lead aVL. Transition occurs normally (between leads V3-to-V4). T waves are somewhat peaked in several leads. There is a hint of ST segment flattening (in leads II, III, aVF - as well as in lead aVL and V6). There is isolated symmetric T wave inversion in lead aVL.
CLINICAL IMPRESSION: Sinus arrhythmia. Small inferior q waves, and a QS in lead aVL of uncertain significance. Small q in V6. Isolated symmetric T wave inversion in aVL. T wave peaking, and subtle ST segment flattening in several leads. These changes are probably not acute - but strongly suggest clinical correlation (See Comment below).
COMMENT: - In view of the worrisome history (this 45-year-old man presents to the ED with new-onset chest discomfort) - there are 4 ECG findings that should at least be noted and addressed:
- Small and narrow q waves are seen in a number of leads. Small and narrow q waves are commonly seen as a normal finding in one or more of the lateral leads (I,aVL,V4,V5,V6). This reflects the process of septal activation, which normally moves from left-to-right. Thus, the q wave in lead V6 is almost certainly a normal septal q wave. There are also small and narrow inferior q waves (in leads II,III,aVF). On occasion - inferior q waves may also be a normal finding IF seen in association with a relatively vertical QRS axis (as is the case here) and in the absence of other acute findings.
- In lead aVL - there is a deep Q wave (QS complex) and shallow but symmetric T wave inversion. However, as an isolated finding - neither the deep Q wave nor the symmetric T inversion are necessarily abnormal in this lead (See Figure 4 in ECG Review #9).
- T waves are peaked in several leads in Figure 1 (in leads II,III,aVF,V4,V5,V6). Although some T wave peaking may be a normal finding - this should be noted. The presence of T wave peaking always brings up the possibility of hyperkalemia as a cause - although there is nothing else in the clinical scenario given here to suggest hyperkalemia (no mention of renal disease, acidosis, or potassium-retaining drugs). T wave peaking may also be due to ischemia on occasion (which could be relevant given the history of chest discomfort in this patient . . . ).
- There is subtle but real flattening of the ST segment in several leads in Figure 1 (leads II,III,aVF,aVL,V6).
BOTTOM Line: The history in this case is worrisome (a 45-year-old man who presents to the ED with new-onset chest discomfort) - and - a number of findings have been noted in our Descriptive Analysis of his initial ECG (above). That said - we suspect that nothing acute is going on because the changes that are noted are subtle and not necessarily outside the range of normal. That said - we can not tell for sure that nothing acute is going on based on this single tracing.
- The clinical reality is that you will often not be able to tell for sure if acute infarction is occurring from assessment of a single ECG.
- Clinically - A worrisome history by itself is more than enough to justify admission to the hospital to rule out acute infarction. In the absence of a prior ECG for comparison - we would definitely admit this patient with chest discomfort to the hospital. Even IF we had a prior ECG that looked identical to this one - IF the history was of concern, that alone would justify admission to the hospital.