Clinical decision making in adult chest pain with ECG ST-segment elevation : STEMI vs Non-AMI cause of ST-segment abnormality

ED management of Chest pain History Physical Exam Serum marker ECG

Initial ECG High risk group Significant abnormality or confound pattern Pathologic Q waves ST-segment or T wave change LVH LBBB Ventricular paced rhythm 42% incidence of AMI 14% incidence of life threatening events 10% mortality rate

Initial ECG Low risk group Normal Minimal abnormality Unchanged (when compared previous ECG) 14% incidence of AMI 0.6% incidence of life threatening events 0% mortality rate

ST segment elevation ACC/AHA guideline ST segment is measured at At least 0.2mV of elevation in any 1 precordial lead Greater than 0.1mV elevation in at least 2 anatomically contiguous precordial lead or in at least 2 adjacent limb leads ST segment is measured at A point 0.04 msec or 1mm after or the right of the J point at the end of QRS complex

ST segment elevation Magnitude of ST-segment change AMI 4.4mV Summation 15.3mV Non- AMI 1.8mV Summation 7.4mV

ST segment elevation Anatomic distribution ACS : localized (3.4 leads) Non-AMI : more wide spread (4.1 leads) Regarding ST segment depression Specific anatomical distribution is not helpful in diagnosis

ST segment elevation ST segment Contour

ST segment elevation

ST segment elevation

ST segment elevation QRS complex width and Amplitude

ST segment elevation QRS complex width and Amplitude

ST segment elevation QRS complex width and Amplitude

ST segment elevation QRS complex width and Amplitude

ST segment elevation QRS complex width and Amplitude

ST segment elevation LVH : V1 + R wave in V5 or V6  more than 35mm

Medical decision making and diagnostic clinical pathway Widened QRS complex AMI itself does not increase the width of QRS Abnormal intraventricular conduction LBBB, VPR Higher risk of AMI Prompt Dx of AMI is extremely important

Medical decision making and diagnostic clinical pathway Ventricular paced Rhythm

Medical decision making and diagnostic clinical pathway LBBB AMI in LBBB presentation

Medical decision making and diagnostic clinical pathway Large amplitude QRS complex Result in ST-segment/T-wave change Opposite direction to QRS Convex or concave Serial ECG

Medical decision making and diagnostic clinical pathway ST segment contour Convex or oblique Predictor of AMI : sensitivity 77% specificity 97% positive predictive value 94% Don’t use for Rule out !!! But effective in Rule in

Medical decision making and diagnostic clinical pathway Reciprocal ST segment depression ST-segment depression in leads that are opposite to those that exibiting STE Criteria ST-segment depression Presence od ST-segment elevation in distal leads Absence of confounding ECG pattern LVH, LBBB, VPR Sensitivity : 63% PPV : 30% Absence of LVH, LBBB, VPR Sensitivity & PPV : 93%

Medical decision making and diagnostic clinical pathway

Medical decision making and diagnostic clinical pathway Serial ECG “AMI is dynamic and evloving process with a predictable progression of changes” 3-4 hours after 0.5mm change in STE or STD Q-wave development T-wave inversion in 2 or more contiguous lead  AMI sensitivity : 88%

Medical decision making and diagnostic clinical pathway Serial ECG

Case conclusion

Case conclusion

Case conclusion

Case conclusion

Reference Clinical decision making in adult chest pain with ECG ST segment elevation : STEMI vs Non-AMI cause of ST-segment abnormality