Morning Report: 11/20/2012

Here’s Dr. Kong with today’s Morning Report!

 

Regular Wide Complex Tachycardia:

SVT with Aberrancy versus Ventricular Tachycardia

 

 

Definitions:

1. Wide Complex Tachycardia: HR > 100, QRS > 0.12s

2. SVT with Aberrancy: Tachycardia originating above ventricles, (most commonly AVNRT) with apparent or rate related- conduction delay

3. VT: Tachycardia originating from ventricles

 

Etiologies:

1. Ventricular Tachycardia

2. SVT with aberrancy

3. Pre-excitation Tachycardia

4. Tox/ metabolic

5. Pacemaker related

6. Artifact

 

H&P

1. Clinical Info: History and Physical

A. History Favoring VT

a. Older Age

b. Hx MI, CHF, Angina, prior VT/ ICD

c. Home medications/ ingestions; dialysis

B. History Favoring SVT with aberrancy

a. Younger Age

b. Hx prior SVT

c. No signif pmh

C. Exam may reveal predisposing conditions; Vagal maneuver may transiently reduce rate if SVT.

D. VT tends to be faster than SVT with aberrancy, but rate is not diagnostically reliable.

 

Management

 

! WHEN IN DOUBT TREAT AS VT !

 

1. Griffith Algorithm: stablility–> get new and old EKG –> apply stepwise criteria –> treat

A. Stablility

a. Unstable, pulseless: defibrillate Biphasic 200J, Monophasic 360J; Epi 1mg 1:10,000 q3-5min; Amio 300mg, 150mg

b. Unstable, + pulses: Cardioversion 50-100J

c. ABC’s (CAB), ACLS

d. Stable: consider other management

B. EKG

C. Criteria: regular vs irregular

a. If Regular: SVT with aberrancy vs VT.

1. Suggestive of VT (Griffith):

– No RBBB or LBBB

– NW axis (extreme R axis)

– AV dissociation (Independently marching P’s, Capture Beats, Fusion Beats)

2. Other clues (not part of Griffith) suggestive of VT:

– very wide QRS (>140ms RBBB, > 160ms LBBB)

– Precordial Concordance

– Slow initial q or r wave

b. If Irregular: Polymorphic VT vs. Afib with aberrancy vs Afib with pre-excitation (WPW)

1. Eval Amplitude variation, Rate, BBB.

2. Suggestive of polymorphic VT:

– Rate > 200

– Significant Amplitude variability

3. Suggestive of Afib with aberrancy:

– BBB pattern

– Rate < 200

– Small amplitude variability

4. Suggestive of Afib with pre-excitation (WPW):

– Rate can be > 200

– Some amplitude variability; significant variability uncommon

D. Treatment of regular wide complex tachycardia

a. If unstable, defib or cardiovert as above

b. If VT

– Procainamide (IIa recc AHA 2010)

* 20-50 mg/min

* Max 17mg/kg

* give until arrhythmia suppressed, hypotension, QRS duration incrs 50%, or max dose

* Maintenance infusin 1-4 mg/min

* IV, O2 Monitor, Defibrillator pads on, continuous EKG

* Avoid in prolonged QT or CHF

– Amiodarone 150 mg over 10min, repeat as needed, maint infuse mg/min first 6hr

– Sotalol 100mg (1.5mg/kg) over 5min, avoid if prolong QT

c. If SVT with aberrancy

– Adenosine

* Double check: must be Regular, Monomorphic

* 6mg IVP with flush, repeat 12mg, 12mg

* IV, O2 Monitor, Defibrillator pads on, continuous EKG

– CCB’s, BB’s

– Procainamide also effective

d. WHEN IN DOUBT, TREAT AS VT.

e. Adenosine will break some VT (eg RVOT VT), not break some SVT.

f. Tox/metabolic etiologies if present need to be addressed.

E. Treatment of Irregular wide complex tachycardia

a. If unstable, defib or cardiovert as above

b. If VT, careful of degeneration into VF

– Procainamide (IIa recc AHA 2010)

* 20-50 mg/min

* Max 17mg/kg

* give until arrhythmia suppressed, hypotension, QRS duration incrs 50%, or max dose

* Maintenance infusion 1-4 mg/min

* IV, O2 Monitor, Defibrillator pads on, continuous EKG

* Avoid in prolonged QT or CHF

– Amiodarone 150 mg over 10min, repeat as needed, maint infuse mg/min first 6hr

– Sotalol 100mg (1.5mg/kg) over 5min, avoid if prolong QT

– If prolonged QT consider Magnesium and Calcium

c. If afib with aberrancy

– Vagal maneuver

– Adenosine

– CCB, BB

d. If afib with pre excitation

– Procainamide (IIa recc AHA 2010)

e. WHEN IN DOUBT, TREAT AS VT.

 

Sources:

1. Burns, Edward.  VT versus SVT with Aberrancy.  Lifeinthefastlane.com. Retrieved 10/21/12

2. Burns, Edward and Larkin, John.  Pre-excitation Syndromes.  Lifeinthefastlane.com.  Retrieved 10/21/12.

3. Cadogan, MIke, AVNRT for two.  Lifeinthefastlane.com. Retrieved 10/21/12

4. Mattu, Amal. “The Pinnacle: ECG Cases that Would MAke an Electrophysiologist Blush. Lecture, ACEP scientific Assembly Sept 28 – Oct 1 2011. Retrieved 10/21/12

5. Podrid, P, et al. Approach to the Diagnosis and Treatment of Wide Complex Tachycardias. Uptodate.com.  Retrieved 10/21/12.

6. Smith, S. Wide Complex Tachycardia: Ventricular Tachycardia or Supraventricular Tachycardia with Aberrancy?  Dr. Smith’s ECG Blog.  Retrieved 10/21/12

7. Smith, S. WPW Mimicking and obscuring acute MI.  Dr. Smith’s ECG Blog.  Retrieved 10/21/12

8. Subramanian, R. Wide COmplex Tachycardia: Diagnosis and Management in the Emergency Department. Emergency Medicine Practice. June 2008. Vol 10, No6.

9. Yealy, Donald. Dysrhythmias. Roses’ Emergency Medicine, 7th ed. Ch 77.

Thanks Dr. Kong!