Totally Occluded Artery Worksheets

Headshot of Chris Anderson, MD · Clinical Education Director, Pediatrics
Chris Anderson
MD · Clinical Education Director, Pediatrics
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Headshot of Kevin Hodges, Vice Chair, Emergency Medicine
Kevin Hodges
Vice Chair, Emergency Medicine
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Intro paragraph? These worksheets are for self-study only. Answers will not be evaluated.

Instructions for Chapter 14 Worksheets

  1. Complete basic measurements.
  2. Note if ST elevation is present in two or more leads that represent a pattern in Table 14.1. Describe this as ST elevation MI (STEMI) and note the location. In addition, Rule Three of the T Waves applies. ST elevation takes precedence over any associated T wave inversion or ST segment depression.
  3. Provide an interpretation.

 

 

Clinically-Based Critical Thinking: Interpretation

Since ST elevation is present in II, III, and AVF, read STEMI and localize it to the inferior wall. Rule Three of the T Waves applies. Ignore the ST depression in I and AVL, which represent reciprocal changes. The ST elevation is the significant finding. The artery to the inferior wall (usually RCA) is occluded. Therapy to open it is indicated as soon as possible. Short QT may be congenital or acquired and related to drug or electrolytes effect. Sinus bradycardia is common in the setting of acute inferior wall MI.

Worksheet 14.1

Complete the basic measurements, evaluation, and interpretation for the EKG below.

Parameter Measurement Interpretation
HR    
Rhythm    
PR    
QRS    
QT    
QTc    
P direction    
QRS direction    
Abnormal parameter If present, note the leads or location
Inverted T waves  
ST depression  
ST elevation  
Q waves or equivalents  

HR 88, sinus. PR interval is normal. QRS interval is difficult to measure but may be 0.12 seconds or more indicating BBB. Since the end of the QRS points anteriorly in V1 it would be RBBB. There is ST elevation in leads V2 through V6 consistent with STEMI. The likely diagnosis is an occlusive thrombus in the LAD. The overall QRS direction is upward indicating LAHB. Both RBBB and LAHB can be complications of acute anterior wall MI, since both the right and left bundle are in the septum. Therapy is aimed at emergent opening of the artery by angioplasty or thrombolysis.

Worksheet 14.2

Complete the basic measurements, evaluation, and interpretation for the EKG below.

Parameter Measurement Interpretation
HR    
Rhythm    
PR    
QRS    
QT    
QTc    
P direction    
QRS direction    
Abnormal parameter If present, note the leads or location
Inverted T waves  
ST depression  
ST elevation  
Q waves or equivalents  

HR 115, sinus tachycardia. This may represent shock or CHF. The PR interval is normal. The QRS is normal at 0.08 seconds. The QT is 0.320 seconds. The QTc is 0.44 which is high. There is ST elevation in leads V1 to V4. By the Third Rule of the T Waves, ST elevation in two  contiguous leads takes precedence over the ST depression in II, III, and AVF, which represents reciprocal changes. Therapy is aimed at immediate opening of the artery by angioplasty or thrombolysis.

Worksheet 14.3

Complete the basic measurements, evaluation, and interpretation for the EKG below.

Parameter Measurement Interpretation
HR    
Rhythm    
PR    
QRS    
QT    
QTc    
P direction    
QRS direction    
Abnormal parameter If present, note the leads or location
Inverted T waves  
ST depression  
ST elevation  
Q waves or equivalents  

The HR is 75, sinus rhythm. The PR interval is long, 0.28, indicating 1°AVB, which is a complication of inferior wall MI. There is ST elevation in II, III, and AVF indicating STEMI. The Third Rule of the T Wave applies, and the ST elevation takes precedence over the ST depression in leads I and AVL. Therapy is aimed at immediate opening of the artery supplying the inferior wall, typically the RCA.