A 50 year old man with sudden altered mental status and inferior STE. Would you give lytics? Yes, but not because of the ECG!

DiscussionFlutter waves are well known to mimic ST deviations, as well as to hide true ischemic ST deviations from the interpreter. In many cases of flutter waves mimicking ST deviations, the expert electrocardiographer can see the morphology of the flutter waves as the cause of apparent STE or STD. Likewise, in some cases of ischemia concealed by flutter waves, the ischemia can be seen despite the flutter waves, whereas in other cases the dysrhythmia must be terminated before the ischemia can be clearly distinguished. Even when flutter waves conceal true ST segment deviations, the cause and effect relationship may be unclear. Tachycardia to this degree can cause ST segment changes in several ways. First, there can simply be diffuse STD (which obligates reciprocal STE in aVR) associated with tachycardia, which are not even necessarily indicative of ischemia. Second, the increased demand created by extreme tachycardia may exceed the ability of the coronary arteries to supply sufficient blood (due to preexisting three vessel or left main disease, with or without ACS). In this case, there is diffuse ischemic STD of subendocardial ischemia, of course with accompanying reciprocal STE in aVR. Finally, if a region of the myocardium supplied y a severely flow-limiting (but not necessarily fully occluded) lesion suddenly undergoes massively increased demand due to acute tachycardia, the supply-demand mismatch may be so great that the tissue undergoes acute transmural ischemia, bo...
Source: Dr. Smith's ECG Blog - Category: Cardiology Authors: Source Type: blogs