What is the definition of a Wide Complex Tachycardia?
Why is it important to distinguish between a supraventricular and a ventricular origin of the arrhythmia?
How can Ventricular Tachycardia and Supraventricular Tachycardia be estimated?
In the inpatient setting, what percentage of Wide Complex Tachyarrhythmias are due to Ventricular Tachycardia?
With this fact in mind, proceed with the following questions:
Which drugs prolong can cause Wide Complex Tachyarrhythmias?
What is the treatment of Ventricular Tachycardia?
What is the relationship between sustained VT and non-sustained VT and mortality in the post-MI period?
Name the common causes of wide complex tachyarrhythmia (WCT)
These are the less common mechanisms of WCT
See the EKGs
See the Algorithms
- a heart rate of > 100 beats per minute
- a QRS complex that is wider than 0.12 seconds
Why is it important to distinguish between a supraventricular and a ventricular origin of the arrhythmia?
- it changes the management
- the drugs used in the management of SVT (adenosine, beta blockers, and calcium channel blockers) can cause severe hemodynamic instability if used erroneously in the setting of VT
How can Ventricular Tachycardia and Supraventricular Tachycardia be estimated?
- by clinical history
- if the patient is older and has a prior myocardial infarction, think VT
- if the patient is younger, is hemodynamically stable, and has a history of paroxysmal tachycardias, think SVT
In the inpatient setting, what percentage of Wide Complex Tachyarrhythmias are due to Ventricular Tachycardia?
- 80%
With this fact in mind, proceed with the following questions:
- does the patient have underlying structural heart disease?
- does the patient have a pacemaker, implantable cardiac defibrillator (ICD), or a wide QRS at baseline (due to RBBB, LBBB or intraventricular conduction delay)?
Which drugs prolong can cause Wide Complex Tachyarrhythmias?
- drugs that prolong the QT interval
- drugs that increase the risk for polymorphic Ventricular Tachycardia and Torsades de Pointes
- a full list is here: http://crediblemeds.org/everyone/composite-list-all-qtdrugs/?rf=US
- the list includes anti-arrhythmics like Amiodarone, Dofetilide, Procainamide, and Sotalol; Antibiotics like Azithromycin and Ciprofloxacin
What is the treatment of Ventricular Tachycardia?
- cardioversion for sustained Ventricular Tachycardia
- Lidocaine or amiodarone for 24 - 48 hours
What is the relationship between sustained VT and non-sustained VT and mortality in the post-MI period?
- NSVT, or VT lasting < 30 seconds, is common in the first 24 hours after an MI
- NSVT is only associated with increased mortality when occurring late in the post-MI course
- Sustained VT, or VT lasting > 30 seconds, during the first 48 hours after an acute MI is associated with increased in-hospital mortality
Name the common causes of wide complex tachyarrhythmia (WCT)
- Ventricular Tachycardia
- Supraventricular Tachycardia with Aberrancy
These are the less common mechanisms of WCT
- antidromic AVRT
- hyperkalemia-induced arrhythmia
- pacemaker-induced arrhythmia
See the EKGs
See the Algorithms