Non-conducted PAC’s vs. Mobitz II
Episode 99
July 22, 2013
Non-conducted PAC’s vs. Mobitz II
Episode 99
July 22, 2013

How is the heart like a toilet??!!  Watch this week’s video and you will never flush before your toilet is finished repolarizing ever again!

 
  • Non-conducted PACs produce pauses that may mimic Mobitz II
  • Remember that the P-P interval must remain contant in Mobitz blocks
  • Management is very different for PAC’s vs. Mobitz II. True Mobitz II will require invasive procedures whereas non-conducted PAC’s are generally benign
Review of Wellens Syndrome
Episode 96
July 1, 2013

Wellens Syndrome

  • T-wave abnormality in precordial leads (V2-V3, +/-V4)
  • Specific for obstructed proximal LAD lesion
  • High risk for extensive anterior wall MI and death
  • 2 types
    • Type 1-Deeply symmetric TWI
    • Type 2- Biphasic T waves with terminal TWI. Goes up first, then down (often misdiagnosed as “normal” or “non-specific T-wave abnormality”).

  • ST changes are often absent and patient can be chest pain free
  • Cardiac biomarkers often initially normal
  • Medical management usually ineffective and patients are best treated with PCI, treadmill stress testing may be hazardous.
  • Do not diagnose in the presence of large amplitude QRS complexes
  • When in doubt get serial ECG’s!

Wellens, make sure you know about it. These will help…


 
Review of Wellens Syndrome
Episode 96
July 1, 2013

Wellens Syndrome

  • T-wave abnormality in precordial leads (V2-V3, +/-V4)
  • Specific for obstructed proximal LAD lesion
  • High risk for extensive anterior wall MI and death
  • 2 types
    • Type 1-Deeply symmetric TWI
    • Type 2- Biphasic T waves with terminal TWI. Goes up first, then down (often misdiagnosed as “normal” or “non-specific T-wave abnormality”).

  • ST changes are often absent and patient can be chest pain free
  • Cardiac biomarkers often initially normal
  • Medical management usually ineffective and patients are best treated with PCI, treadmill stress testing may be hazardous.
  • Do not diagnose in the presence of large amplitude QRS complexes
  • When in doubt get serial ECG’s!

Wellens, make sure you know about it. These will help…


 
Scarbossa’s criteria identifies MI in patients with LBBB 
Episode 94
June 17, 2013

Tombstones, checkmarks, and bundles, oh my!

Criteria for left bundle branch block (LBBB)

  • Widened QRS > 0.12 sec in adults
  • Broad notched or slurred R waves in I and V6 WITHOUT Q-waves
  • Broad S waves in V1, V2, V3, may have a small r wave

LBBB causes ST-segment and T wave changes that make the diagnosis of acute MI difficult. Patients with LBBB can be expected to have ST-segment and T waves that are discordant to the direction of the QRS complex. This is expected and referred to as the “rule of appropriate discordance”. In fact, it is very concerning when the QRS complex and the ST-segment are concordant (point in same direction).

You CAN diagnose MI in LBBB, once you understand Sgarbossa’s criteria.

Sgarbossa’s criteria is used to diagnose MI in the setting of a known chronic LBBB. The following 3 ECG criteria can help diagnose AMI in patients with LBBB.

1. STE ≥ 1mm concordant with QRS deflection in any single lead (odds ratios for AMI of 25.2!)

2. STD ≥ 1mm in V1, V2, OR V3 that is concordant. Does NOT need to be in contiguous leads (odds ratios for AMI of 6.0)

3. Discordant STE ≥ 5mm (lower specificity) or STE >20% of size of QRS.


Everything you nees to know about Scarbossa…
Scarbossa’s criteria identifies MI in patients with LBBB 
Episode 94
June 17, 2013

Tombstones, checkmarks, and bundles, oh my!

Criteria for left bundle branch block (LBBB)

  • Widened QRS > 0.12 sec in adults
  • Broad notched or slurred R waves in I and V6 WITHOUT Q-waves
  • Broad S waves in V1, V2, V3, may have a small r wave

LBBB causes ST-segment and T wave changes that make the diagnosis of acute MI difficult. Patients with LBBB can be expected to have ST-segment and T waves that are discordant to the direction of the QRS complex. This is expected and referred to as the “rule of appropriate discordance”. In fact, it is very concerning when the QRS complex and the ST-segment are concordant (point in same direction).

You CAN diagnose MI in LBBB, once you understand Sgarbossa’s criteria.

Sgarbossa’s criteria is used to diagnose MI in the setting of a known chronic LBBB. The following 3 ECG criteria can help diagnose AMI in patients with LBBB.

1. STE ≥ 1mm concordant with QRS deflection in any single lead (odds ratios for AMI of 25.2!)

2. STD ≥ 1mm in V1, V2, OR V3 that is concordant. Does NOT need to be in contiguous leads (odds ratios for AMI of 6.0)

3. Discordant STE ≥ 5mm (lower specificity) or STE >20% of size of QRS.


Everything you nees to know about Scarbossa…
  ECG findings in Thoracic Aortic Dissection
Episode 93
June 10, 2013

Just a simple inferior STEMI? Don’t be too sure….

About 4-8% of Thoracic Aortic Dissection’s (TAD)
will present with ECG signs of STEMI
  • Usually inferior ST-elevation or diffuse ischemia with ST-depression
  • Typical for inferior STEMI’s to have reciprocal changes in leads I & aVL
  • Consider posterior and right ventricular extension of infarction with inferior STEMI
  • Not all chest pain (CP) = ACS, don’t forget to consider TAD
    • CP + new neurological SSx → TAD
    • CP + new diastolic murmur → TAD
    • CP + new renal failure → TAD
    • CP + new ischemic extremities → TAD
    • Remember that TAD can dissect backward and cause hemorrhagic pericardial effusions…careful with that heparin gtt!


  ECG findings in Thoracic Aortic Dissection
Episode 93
June 10, 2013

Just a simple inferior STEMI? Don’t be too sure….

About 4-8% of Thoracic Aortic Dissection’s (TAD)
will present with ECG signs of STEMI
  • Usually inferior ST-elevation or diffuse ischemia with ST-depression
  • Typical for inferior STEMI’s to have reciprocal changes in leads I & aVL
  • Consider posterior and right ventricular extension of infarction with inferior STEMI
  • Not all chest pain (CP) = ACS, don’t forget to consider TAD
    • CP + new neurological SSx → TAD
    • CP + new diastolic murmur → TAD
    • CP + new renal failure → TAD
    • CP + new ischemic extremities → TAD
    • Remember that TAD can dissect backward and cause hemorrhagic pericardial effusions…careful with that heparin gtt!


Digoxin Toxicity & AV block: Will IV calcium cause “stone heart”?
Episode 91
May 28, 2013
Digoxin Toxicity & AV block: Will IV calcium cause “stone heart”?
Episode 91
May 28, 2013

Potassium, digoxin, calcium, AVBs, stone heart…so much to discuss this week!

  • When considering AV blocks, always pay attention to the PR segments to help distinguish between Mobitz I, Mobitz II, & AVD/CHB.
  • Hyperkalemia can cause just about anything, including AV blocks!
  • Calcium in probably safe in digoxin toxicity.
  • Levine et al. in their retrospective review of 129 patients who had digoxin toxicity, found that IV calcium did not seem to cause malignant dysrhythmias or increase mortality. They found no support for the historical belief that calcium is contraindicated for these hyperkalemic patients.
  T-wave changes of severe hypokalemia
  T-wave changes of severe hypokalemia
Episode 89
May 13, 2013

 
Ever heard of “Reverse-Wellens syndrome” ? Watch this to learn about this dangerous Wellens syndrome mimic.
“Reverse-Wellens” waves deflect downward before going up & are seen in cases of severe hypokalemia that produce U-waves. See below…

Compare this to Wellens waves that may also be biphasic, but deflect upward before going down!
What anatomical distribution of ischemia is associated with the ECG changes of Wellens Syndrome? Review Wellens by watching the videos below!  

Review these previous episodes and master Wellens syndrome…

 
  Dangers of  “Non-specific ST-segment abnormalities” ​
  Dangers of  “Non-specific ST-segment abnormalities” ​
Episode 87
April 29, 2013

 
 
When in doubt, order serial ECG!
Get good at ECG’s and you will save lives!
 
  • ST-segment depression or elevation <1mm are typically interpreted as “Non-specific ST-segment abnormalities” by the ECG machine. Ischemia causes dynamic ECG changes, and this can be an early sign of MI.
  • Beware of STE in aVR! STE in aVR with other ischemic findings is BAD! (LMCA occlusion, proximal LAD occlusion, or triple vessel disease)
 

Learn more about the forgotten lead, aVR! This episode is loaded with important references you can share with your cardiologist as needed…
 

 
Anteroseptal ischemia or Posterior STEMI? ​
Episode 86
April 22, 2013

Syncope leads to cardiac arrest within 15 minutes. What’s the diagnosis? Find out in 15 minutes!​

Always think of the following differentials every time you are looking at an ECG in a patient who presents with syncope:
  1. Acute Coronary Syndrome
  2. Tachy/Brady-dysrhythmias (AV-blocks)
  3. WPW
  4. Brugada syndrome
  5. Hypertrophic cardiomyopathy
  6. Long/Short QT syndrome
  7. Arrhythmogenic RV dysplasia
 
Differential for ST-Depression in Anteroseptal Leads
  • Posterior STEMI
  • Anteroseptal ischemia
  • Miscellaneous
  • RBBB, Hypokalemia, etc.
Posterior Myocardial Infarction
  • ST-segment depression (STD)  instead of ST-elevation (STE)
  • Usually associated with Inferior MI due to RCA or circumflex occlusion
  • Mirror image of septal MI in leads V1-V2
  • Large R-waves instead of Q’s
  • Upright T-waves instead of T-wave inversions

ECG changes in leads V1-V3

Septal MI

STE

Inverted

T-waves

Q-waves develop over hours

Posterior MI

STD

Upright

T-waves

Tall R’s develop over hours

 

 



 
Anteroseptal ischemia or Posterior STEMI? ​
Episode 86
April 22, 2013

Syncope leads to cardiac arrest within 15 minutes. What’s the diagnosis? Find out in 15 minutes!​

Always think of the following differentials every time you are looking at an ECG in a patient who presents with syncope:
  1. Acute Coronary Syndrome
  2. Tachy/Brady-dysrhythmias (AV-blocks)
  3. WPW
  4. Brugada syndrome
  5. Hypertrophic cardiomyopathy
  6. Long/Short QT syndrome
  7. Arrhythmogenic RV dysplasia
 
Differential for ST-Depression in Anteroseptal Leads
  • Posterior STEMI
  • Anteroseptal ischemia
  • Miscellaneous
  • RBBB, Hypokalemia, etc.
Posterior Myocardial Infarction
  • ST-segment depression (STD)  instead of ST-elevation (STE)
  • Usually associated with Inferior MI due to RCA or circumflex occlusion
  • Mirror image of septal MI in leads V1-V2
  • Large R-waves instead of Q’s
  • Upright T-waves instead of T-wave inversions

ECG changes in leads V1-V3

Septal MI

STE

Inverted

T-waves

Q-waves develop over hours

Posterior MI

STD

Upright

T-waves

Tall R’s develop over hours

 

 


Everything you need to freshen up your skills on this topic…

 
When pericarditis isn’t pericarditis
Episode 84
April 8, 2013

Young patients can and will have MIs. Don’t miss the diagnosis!

Pericarditis vs. STEMI
  • First, make sure you are not missing an acute MI by looking for factors strongly associated with AMI. Ask yourself:
  1. Is there reciprocal ST-segment depression in any leads (except for aVR and V1)? If yes, it’s a STEMI. If not,…
  2. Is the ST-segment morphology convex or horizontal? If yes, it’s a STEMI. If not,…
  3. Is the STE in lead III> the STE in lead II? If yes, it’s a STEMI.
  4. Are there new Q waves? If yes, it’s likely a STEMI
 
  • If the answer to all three questions is no, then you should consider the possibility of it being pericarditis. Factors associated with pericarditis:
  1. Is there pronounced PR-segment depression in all leads? If so, it’s possibly pericarditis. (But could also be due to cardiac ischemia, so make sure you are not missing an MI first by answering the first 3 questions!)
  2. Is there a pericardial friction rub? If so, it’s possibly pericarditis
When in doubt, do serial EKG’s!


 
When pericarditis isn’t pericarditis
Episode 84
April 8, 2013

Young patients can and will have MIs. Don’t miss the diagnosis!

Pericarditis vs. STEMI
  • First, make sure you are not missing an acute MI by looking for factors strongly associated with AMI. Ask yourself:
  1. Is there reciprocal ST-segment depression in any leads (except for aVR and V1)? If yes, it’s a STEMI. If not,…
  2. Is the ST-segment morphology convex or horizontal? If yes, it’s a STEMI. If not,…
  3. Is the STE in lead III> the STE in lead II? If yes, it’s a STEMI.
  4. Are there new Q waves? If yes, it’s likely a STEMI
 
  • If the answer to all three questions is no, then you should consider the possibility of it being pericarditis. Factors associated with pericarditis:
  1. Is there pronounced PR-segment depression in all leads? If so, it’s possibly pericarditis. (But could also be due to cardiac ischemia, so make sure you are not missing an MI first by answering the first 3 questions!)
  2. Is there a pericardial friction rub? If so, it’s possibly pericarditis
When in doubt, do serial EKG’s!

Everything you every wanted to know about diffuse ST-segment elevation, covered in these related episodes
 

 
How to diagnose acute MI in patients with known LBBB
Episode 83
April 1, 2013

Myth: “You can not diagnose acute MI in patients with LBBB”

Don’t believe it! You CAN diagnose MI in LBBB,

once you understand Sgarbossa’s criteria.

Complete LBBB causes delayed left ventricular depolarization causing a wide QRS (>120 ms in adults). Findings include broad notched (RSR’ or “rabbit ear pattern”) in leads I, aVL, V5, & V6. Also, absence of Q waves in leads I, V5, & V6.

LBBB causes ST-segment and T wave changes that make the diagnosis of acute MI difficult. Patients with LBBB can be expected to have ST-segment and T waves that are discordant to the direction of the QRS complex. This is expected and referred to as the “rule appropriate discordance”. In fact, it is very concerning when the QRS complex and the ST-segment are concordant (point in same direction).

Positive concordance = STE or positive T waves in leads with positive QRS complexes

Negative concordance = STD or negative T waves in leads with negative QRS complexes

Sgarbossa’s criteria is used to diagnose MI in the setting of a known chronic LBBB. When combined, the following 3 ECG criteria yielded a sensitivity and specificity of approximately 78% and 90%, respectively.

  1. STE ≥ 1mm concordant with QRS deflection in any single lead (odds ratios for AMI of 25.2!)
  2. STD ≥ 1mm in V1, V2, OR V3 that is concordant. Does NOT need to be in contiguous leads (odds ratios for AMI of 6.0)
  3. Discordant STE ≥ 5mm (lower specificity) or STE >20% of size of QRS.

Still don’t believe it? Keep watching…

References:

How to diagnose acute MI in patients with known LBBB
Episode 83
April 1, 2013

Myth: “You can not diagnose acute MI in patients with LBBB”

Don’t believe it! You CAN diagnose MI in LBBB,

once you understand Sgarbossa’s criteria.

Complete LBBB causes delayed left ventricular depolarization causing a wide QRS (>120 ms in adults). Findings include broad notched (RSR’ or “rabbit ear pattern”) in leads I, aVL, V5, & V6. Also, absence of Q waves in leads I, V5, & V6.

LBBB causes ST-segment and T wave changes that make the diagnosis of acute MI difficult. Patients with LBBB can be expected to have ST-segment and T waves that are discordant to the direction of the QRS complex. This is expected and referred to as the “rule appropriate discordance”. In fact, it is very concerning when the QRS complex and the ST-segment are concordant (point in same direction).

Positive concordance = STE or positive T waves in leads with positive QRS complexes

Negative concordance = STD or negative T waves in leads with negative QRS complexes

Sgarbossa’s criteria is used to diagnose MI in the setting of a known chronic LBBB. When combined, the following 3 ECG criteria yielded a sensitivity and specificity of approximately 78% and 90%, respectively.

  1. STE ≥ 1mm concordant with QRS deflection in any single lead (odds ratios for AMI of 25.2!)
  2. STD ≥ 1mm in V1, V2, OR V3 that is concordant. Does NOT need to be in contiguous leads (odds ratios for AMI of 6.0)
  3. Discordant STE ≥ 5mm (lower specificity) or STE >20% of size of QRS.

Still don’t believe it? Keep watching…

References: