The myth of Medusa & stone heart revealed…
Episode 127
February 3, 2014
Bizarre rhythm? Think about hyperkalemia!
 Knowing all the variations of ECG findings in hyperkalemia saves lives.
 
ECG finding associated with hyperkalemia:
  • Peaked T-waves
  • Widening of the QRS
  • Prolonged PR
  • Flattening and eventual loss for p-waves
  • Advanced AV Blocks and sinus pauses
  • Pseudo ACS, new BBB’s, ST-segment changes
  • Sine wave morphology
In digoxin-intoxicated humans, IV calcium does not seem to cause malignant dysrhythmias or increase mortality. Evidence does not support the historical belief that calcium administration is contraindicated in digoxin-toxic patients. 

 

Reference

Levine M, Nikkanen H, Pallin DJ. The Effects of Intravenous Calcium in Patients with Digoxin Toxicity. J Emerg Med. 2011;40(1):41–46. Pubmed Link

The myth of Medusa & stone heart revealed…
Episode 127
February 3, 2014
Bizarre rhythm? Think about hyperkalemia!
 Knowing all the variations of ECG findings in hyperkalemia saves lives.
 
ECG finding associated with hyperkalemia:
  • Peaked T-waves
  • Widening of the QRS
  • Prolonged PR
  • Flattening and eventual loss for p-waves
  • Advanced AV Blocks and sinus pauses
  • Pseudo ACS, new BBB’s, ST-segment changes
  • Sine wave morphology
In digoxin-intoxicated humans, IV calcium does not seem to cause malignant dysrhythmias or increase mortality. Evidence does not support the historical belief that calcium administration is contraindicated in digoxin-toxic patients. 

Search the site to watch more videos on the bizarre ECG manifestations of #hyperkalemia
 

Reference

Levine M, Nikkanen H, Pallin DJ. The Effects of Intravenous Calcium in Patients with Digoxin Toxicity. J Emerg Med. 2011;40(1):41–46. Pubmed Link

How many ECGs does it take to save a life?
Episode 126
How many ECGs does it take to save a life?
Episode 126
January 27, 2014

When in doubt, get serial ECGs!

  • Reciprocal changes can precede ST-elevation (STE) in MI

  • New TWI in aVL can be the first sign of an Inferior STEMI

  • Get serial ECGs​ in patients with persistant or changing chest pain

  • Check out more cases with #Early reciprocal changes


March 28-31st
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How to avoid misdiagnosis of Mobitz I
Episode 125
January 20, 2014
 

Why does this simple rhythm get misdiagnosed so much?

Don’t trust the computer’s ECG interpretation!

  • Atrial fibrillation should produce an IRREGULARLY irregular ventricular response

  • Always scrutinize lead V1 (closest to the sinus node) for P-waves (atrial activity)

  • Pay close attention to the PR-interval to avoid missing AV blocks

  • If the rhythm is REGULARLY irregular with grouped or “clumped beats” consider:

  1. Premature atrial contractions (PACs)

  2. 2nd degree AV blocks (Mobitz I and Mobitz II)


Want more cases? To review previous episodes & prove your ECG machine wrong, check out #ClumpedBeats

How to avoid misdiagnosis of Mobitz I
Episode 125
January 20, 2014
 

Why does this simple rhythm get misdiagnosed so much?

Don’t trust the computer’s ECG interpretation!

  • Atrial fibrillation should produce an IRREGULARLY irregular ventricular response

  • Always scrutinize lead V1 (closest to the sinus node) for P-waves (atrial activity)

  • Pay close attention to the PR-interval to avoid missing AV blocks

  • If the rhythm is REGULARLY irregular with grouped or “clumped beats” consider:

  1. Premature atrial contractions (PACs)

  2. 2nd degree AV blocks (Mobitz I and Mobitz II)


Want more cases? To review previous episodes & prove your ECG machine wrong, check out #ClumpedBeats

Pacemakers & Acidosis
Episode 124
January 13, 2014

Can pacemakers prevent syphilis? Find out here! 


ECG findings in Hyperkalemia
  • Peaked T-waves
  • Widening of the QRS
  • Prolonged PR
  • Flattening and eventual loss for p-waves
  • Advanced AV Blocks and sinus pauses
  • Pseudo ACS, new BBB’s, ST-segment changes
  • Sine wave morphology
Really wide QRS? Always consider Hyperkalemia/Acidosis & Overdose
Don’t be misled by pacers,which may not work well in acidosis!
Pacemakers & Acidosis
Episode 124
January 13, 2014

Can pacemakers prevent syphilis? Find out here! 


ECG findings in Hyperkalemia
  • Peaked T-waves
  • Widening of the QRS
  • Prolonged PR
  • Flattening and eventual loss for p-waves
  • Advanced AV Blocks and sinus pauses
  • Pseudo ACS, new BBB’s, ST-segment changes
  • Sine wave morphology
Really wide QRS? Always consider Hyperkalemia/Acidosis & Overdose
Don’t be misled by pacers,which may not work well in acidosis!

Knowing this stuff saves lives! For more practice check out…#Hyperkalemia
Himalayan T waves
Episode 123
Himalayan T waves
Episode 123
January 6, 2014

You’ll never look at the mountains the same way again


Himalayan T waves 

  • Giant broad and spiked T waves 
  • Associated with syncope & seizures (due to torsades)
  • Think of congital long QT (Jervell and Lange-Nielsen syndrome)
  • Can also be seen in severe hypokalemia 

Check out this link for a case of congenital long QT with Himalayan T waves and a QTc of 900ms! ​

Also, search these tags for more practice with #T-waves & #Prolonged-QT

Low Voltage QRS Differential
Episode 122
December 30, 2013

Electrocardiographic voltagemia. What’s the significance?

Low Voltage Definition
  • QRS amplitudes in limb leads all < 5 mm or in all chest leads < 10mm (specific definition)
  • QRS amplitudes in I+II+III < 15 mm or V1+V2+V3 < 30 mm (sensitive definition)
Low Voltage QRS Differential
  • “Low Power”
    • Myxedema (severe hypothyroidism)
    • Infiltrative diseases (Amyloid, Sarcoid)
    • End stage cardiomyopathy
  • Conduction blockage
    • Fluid/Effusion (pericardial or pleural)
    • Fat (obesity)
    • Air (COPD)
Don’t rely only on electrical alternans to diagnose pericardial effusions.
Low voltage + Tachycardia = Pericardial effusion until proven otherwise!
Low Voltage QRS Differential
Episode 122
December 30, 2013

Electrocardiographic voltagemia. What’s the significance?

Low Voltage Definition
  • QRS amplitudes in limb leads all < 5 mm or in all chest leads < 10mm (specific definition)
  • QRS amplitudes in I+II+III < 15 mm or V1+V2+V3 < 30 mm (sensitive definition)
Low Voltage QRS Differential
  • “Low Power”
    • Myxedema (severe hypothyroidism)
    • Infiltrative diseases (Amyloid, Sarcoid)
    • End stage cardiomyopathy
  • Conduction blockage
    • Fluid/Effusion (pericardial or pleural)
    • Fat (obesity)
    • Air (COPD)
Don’t rely only on electrical alternans to diagnose pericardial effusions.
Low voltage + Tachycardia = Pericardial effusion until proven otherwise!
ECG findings in Hypothermia
Episode 121
December 23, 2013

Elderly patient found down. Better know this for the Boards! 


Osborn waves (a.k.a. J waves)
  • positive deflections at junction between the QRS complex and ST-segment
  • repolarization abnormality caused by exaggerated outward K+ current
  • usually observed in patients with hypothermia
ECG findings in Hypothermia
  • Osborn waves
  • Sinus brady, junctional rhythm
  • Prolongation of all intervals
  • Slow irregular Afib
  • Ventricular fibrillation
  • Asystole
ECG findings in Hypothermia
Episode 121
December 23, 2013

Elderly patient found down. Better know this for the Boards! 


Osborn waves (a.k.a. J waves)
  • positive deflections at junction between the QRS complex and ST-segment
  • repolarization abnormality caused by exaggerated outward K+ current
  • usually observed in patients with hypothermia
ECG findings in Hypothermia
  • Osborn waves
  • Sinus brady, junctional rhythm
  • Prolongation of all intervals
  • Slow irregular Afib
  • Ventricular fibrillation
  • Asystole
T-wave Inversions & ST-Elevation
Episode 120
December 16, 2013

Are you an arrogant schmuck? Find out in 20 minutes!


New T-wave inversion in aVL may be a reciprocal change!

  • Reciprocal changes can precede ST-elevation (STE) in MI
  • New TWI in aVL can be the first sign of an inferior STEMI
  • When in doubt, get serial ECGs
  • STE is complicated
  • Use the J-point, 2 contiguous leads
    • Women: 1.5 mm in V2-V3 and 1 mm in all other leads
    • Men < 40yo: 2.5 mm in V2-V3
    • Men > 40yo: 2 mm in V2-V3 and 1 mm in all other leads
  • ​Pay attention to ST and T-wave morphology
  • Consult cardiology for joint decision-making

Search #Early reciprocal changes to check out similar cases


References

Wagner GS, Macfarlane P, Wellens H, et al. AHA/ACCF/HRS Recommendations for the Standardization and Interpretation of the Electrocardiogram. J Am Coll Cardiol. 2009;53(11):1003–1011. Pubmed Link

Thygesen K, Alpert JS, Jaffe AS, et al. Third Universal Definition of Myocardial Infarction. J Am Coll Cardiol. 2012;60(16):1581–1598. Pubmed Link

O’Gara PT, Kushner FG, Ascheim DD, et al. 2013 ACCF/AHA Guideline for the Management of ST-Elevation Myocardial Infarction. J Am Coll Cardiol. 2013;61(4):e78–e140. Pubmed Link
 
T-wave Inversions & ST-Elevation
Episode 120
December 16, 2013

Are you an arrogant schmuck? Find out in 20 minutes!


New T-wave inversion in aVL may be a reciprocal change!

  • Reciprocal changes can precede ST-elevation (STE) in MI
  • New TWI in aVL can be the first sign of an inferior STEMI
  • When in doubt, get serial ECGs
  • STE is complicated
  • Use the J-point, 2 contiguous leads
    • Women: 1.5 mm in V2-V3 and 1 mm in all other leads
    • Men < 40yo: 2.5 mm in V2-V3
    • Men > 40yo: 2 mm in V2-V3 and 1 mm in all other leads
  • ​Pay attention to ST and T-wave morphology
  • Consult cardiology for joint decision-making

Search #Early reciprocal changes to check out similar cases


References

Wagner GS, Macfarlane P, Wellens H, et al. AHA/ACCF/HRS Recommendations for the Standardization and Interpretation of the Electrocardiogram. J Am Coll Cardiol. 2009;53(11):1003–1011. Pubmed Link

Thygesen K, Alpert JS, Jaffe AS, et al. Third Universal Definition of Myocardial Infarction. J Am Coll Cardiol. 2012;60(16):1581–1598. Pubmed Link

O’Gara PT, Kushner FG, Ascheim DD, et al. 2013 ACCF/AHA Guideline for the Management of ST-Elevation Myocardial Infarction. J Am Coll Cardiol. 2013;61(4):e78–e140. Pubmed Link
 
How to identify MI in paced rhythms
Episode 119
December 9, 2013

Can you read ischemia with a pacemaker???


You can diagnose MI in paced rhythms!

  • Paced rhythms cause ST-segment & T wave changes that can make the identification of acute MI difficult

  • Patients with paced rhythms can be expected to have ST segment & T wave changes that are discordant to the direction of the QRS complex

    • ​This is normal & referred to as the “Rule of Appropriate Discordance”

  • ST-segment deviations that are concordant (in same direction) to the QRS complex are abnormal

Sgarbossa’s criteria can be used to diagnose MI,

in the setting of both paced rhythms & LBBB

Here is what to look for:

     1. Concordant ST elevation ≥ 1mm in any single lead

     2. Concordant ST depression ≥ 1mm in either V1, V2, or V3

     3. Excessively discordant ST elevation ≥ 5mm in any lead


​Do you remember what the Modified Sgarbossa rule is & how to use it?

If not, check out …The Modified Sgarbossa Rule


References

Sgarbossa EB. Recent advances in the electrocardiographic diagnosis of myocardial infarction: left bundle branch block and pacing. Pacing Clin Electrophysiol. 1996;19(9):1370–1379. Pubmed Link

Sgarbossa EB, Pinski SL, Gates KB, Wagner GS. Early electrocardiographic diagnosis of acute myocardial infarction in the presence of ventricular paced rhythm. GUSTO-I investigators. Am J Cardiol. 1996;77(5):423–424. Pubmed Link

Maloy KR, Bhat R, Davis J, Reed K, Morrissey R. Sgarbossa Criteria are Highly Specific for Acute Myocardial Infarction with Pacemakers. West J Emerg Med. 2010;11(4):354–357. Pubmed Link

Schaaf SG, Tabas JA, Smith SW. A patient with a paced rhythms presenting with chest pain and hypotension. JAMA Intern Med. 2013. Epub ahead of print. Pubmed Link
How to identify MI in paced rhythms
Episode 119
December 9, 2013

Can you read ischemia with a pacemaker???


You can diagnose MI in paced rhythms!

  • Paced rhythms cause ST-segment & T wave changes that can make the identification of acute MI difficult

  • Patients with paced rhythms can be expected to have ST segment & T wave changes that are discordant to the direction of the QRS complex

    • ​This is normal & referred to as the “Rule of Appropriate Discordance”

  • ST-segment deviations that are concordant (in same direction) to the QRS complex are abnormal

Sgarbossa’s criteria can be used to diagnose MI,

in the setting of both paced rhythms & LBBB

Here is what to look for:

     1. Concordant ST elevation ≥ 1mm in any single lead

     2. Concordant ST depression ≥ 1mm in either V1, V2, or V3

     3. Excessively discordant ST elevation ≥ 5mm in any lead


​Do you remember what the Modified Sgarbossa rule is & how to use it?

If not, check out …The Modified Sgarbossa Rule


References

Sgarbossa EB. Recent advances in the electrocardiographic diagnosis of myocardial infarction: left bundle branch block and pacing. Pacing Clin Electrophysiol. 1996;19(9):1370–1379. Pubmed Link

Sgarbossa EB, Pinski SL, Gates KB, Wagner GS. Early electrocardiographic diagnosis of acute myocardial infarction in the presence of ventricular paced rhythm. GUSTO-I investigators. Am J Cardiol. 1996;77(5):423–424. Pubmed Link

Maloy KR, Bhat R, Davis J, Reed K, Morrissey R. Sgarbossa Criteria are Highly Specific for Acute Myocardial Infarction with Pacemakers. West J Emerg Med. 2010;11(4):354–357. Pubmed Link

Schaaf SG, Tabas JA, Smith SW. A patient with a paced rhythms presenting with chest pain and hypotension. JAMA Intern Med. 2013. Epub ahead of print. Pubmed Link
Systematic ECG interpretation saves lives
Episode 118
December 2, 2013

"Save of the Month" from Lehigh Valley EM Residency, Pennsylvania

5 Step Approach to ECG Interpretation
  1. Rate and Rhythm
  2. Axis
  3. Intervals
  4. Enlargement
  5. Ischemia & Infarction (Q-waves, ST-segment changes, T-wave inversions)
​​Be systematic when interpreting the ECG. Recognize abnormalities and stop to think about the differential diagnoses that explain them. Here are some can’t miss differentials from this week’s case: 
 
Causes of Slow Atrial Fibrillation
  • Medication Toxicity with known A Fib (Digoxin, CCB/BB, etc.)
  • Hypothermia
Causes of Rightward Axis (RAD)
  • Left posterior fascicular block
  • Lateral MI (from Q-waves in lead I)
  • Right ventricular hypertrophy
  • Pulmonary HTN - Acute (PE) and chronic (COPD) lung disease
  • Ventricular ectopy (VT)
  • Hyperkalemia
  • Na2+ channel blocking drugs (e.g. TCA’s, Quinidine & Anti-arrhythmics)
  • Lead misplacement
  • Dextrocardia
  • Normal thin adults with horizontally positioned hearts
Causes of QRS prolongation
  • Hypothermia
  • Metabolic/Electrolytes (acidosis, hyperkalemia)
  • Nonspecific intraventricular conduction delay (ex. from LVH) or congenital
  • BBB (LBBB or RBBB) or paced rhythm
  • Ventricular ectopy
  • Pre-excitation (WPW)
  • Na2+channel blocking drug toxicity ​
Prominent R wave (R:S>1) in V1 
  • WPW
  • Posterior MI
  • RBBB or incomplete RBBB
  • Ventricular ectopy
  • RVH
  • Acute RV dilation or strain (massive PE)
  • Hypertrophic cardiomyopathy
  • Na2+channel blocking drug toxicity
  • Hyperkalemia
  • Dextrocardia
  • Misplaced electrodes 
Na2+ channel blocker toxicity
  • Tall R wave in aVR
  • Tall R in V1 (sometimes)
  • Tachycardia (usually)
  • Right Axis Deviation
  • Prolonged QRS

 
Also, check out the #Medication Toxicity category of videos to learn how the ECG can help in tough tox cases.

Systematic ECG interpretation saves lives
Episode 118
December 2, 2013

"Save of the Month" from Lehigh Valley EM Residency, Pennsylvania

5 Step Approach to ECG Interpretation
  1. Rate and Rhythm
  2. Axis
  3. Intervals
  4. Enlargement
  5. Ischemia & Infarction (Q-waves, ST-segment changes, T-wave inversions)
​​Be systematic when interpreting the ECG. Recognize abnormalities and stop to think about the differential diagnoses that explain them. Here are some can’t miss differentials from this week’s case: 
 
Causes of Slow Atrial Fibrillation
  • Medication Toxicity with known A Fib (Digoxin, CCB/BB, etc.)
  • Hypothermia
Causes of Rightward Axis (RAD)
  • Left posterior fascicular block
  • Lateral MI (from Q-waves in lead I)
  • Right ventricular hypertrophy
  • Pulmonary HTN - Acute (PE) and chronic (COPD) lung disease
  • Ventricular ectopy (VT)
  • Hyperkalemia
  • Na2+ channel blocking drugs (e.g. TCA’s, Quinidine & Anti-arrhythmics)
  • Lead misplacement
  • Dextrocardia
  • Normal thin adults with horizontally positioned hearts
Causes of QRS prolongation
  • Hypothermia
  • Metabolic/Electrolytes (acidosis, hyperkalemia)
  • Nonspecific intraventricular conduction delay (ex. from LVH) or congenital
  • BBB (LBBB or RBBB) or paced rhythm
  • Ventricular ectopy
  • Pre-excitation (WPW)
  • Na2+channel blocking drug toxicity ​
Prominent R wave (R:S>1) in V1 
  • WPW
  • Posterior MI
  • RBBB or incomplete RBBB
  • Ventricular ectopy
  • RVH
  • Acute RV dilation or strain (massive PE)
  • Hypertrophic cardiomyopathy
  • Na2+channel blocking drug toxicity
  • Hyperkalemia
  • Dextrocardia
  • Misplaced electrodes 
Na2+ channel blocker toxicity
  • Tall R wave in aVR
  • Tall R in V1 (sometimes)
  • Tachycardia (usually)
  • Right Axis Deviation
  • Prolonged QRS

Want to learn more about fasicular blocks? Watch this…Trifasicular Block
 
Also, check out the #Medication Toxicity category of videos to learn how the ECG can help in tough tox cases.