Lecture 23: Dysrhythmias Part 3 Flashcards
What are the typical causes of junctional arrhythmias?
- Digoxin toxicity
- Lyte abnormalities
- AAD toxicities
- Ischemia
- Myocarditis
How do you treat junctional arrhythmias?
Treat underlying cause.
No need for PPM or A/C
What characterizes an accelerated idioventricular rhythm?
Regular, wide complex with rate of 60-120.
Faster= VT, slower = V escape rhythm
What are the two possible mechanisms for an accelerated idioventricular rhythm?
- Escape rhythm due to suppression of the higher pacemakers/depressed SA node function.
- Slow ventricular tachycardia due to increased automaticity
VT would prob be > 120 BPM
What are the two causes of accelerated idioventricular rhythms?
- Acute MI/reperfusion injury post angioplasty
- Digoxin toxicity
How do you treat an accelerated idioventricular rhythm?
Do not treat unless hemodynamically unstable or more serious arrhythmia present.
What defines sustained vs nonsustained VTach?
- Sustained = Lasts longer than 30s
- Nonsustained = shorter than 30s
VTach = 3+ PVCs consecutively
What is the usual rate of VTach?
160-240 BPM
What are the causes of VTach?
- Acute MI or CAD
- Cardiomyopathy, valvular disease, myocarditis
- Catecholaminergic polymorphic VT (No structural abnormalities)
- Long QT syndrome, brugada (No structural abnormalities)
- TdP due to severe hypokalemia or hypomagnesemia or QT prolongation drugs
What characterizes Long QT Syndrome?
- Recurrent syncope
- Long QT (0.5-0.7s)
- Ventricular arrhythmias/TdP
- Sudden death
Normal QT is 0.35s-0.45s
What congenital abnormality may occur alongside long QT?
Congenital deafness (Jervell-Lange-Nielsen syndrome) or absence thereof (Romano-Ward syndrome)
What kind of defect typically causes LQTS?
- Type 1 and 2 are due to K+ channel defects
- Type 3 is due to Na+ channel mutations
1 & 2 are the MC
When do most lethal cases of LQTS3 occur?
During sleep ):
What characterizes Brugada syndrome?
- Sudden death
- Incomplete RBBB + STE in anterior precordials
- Young, male, asian
- SCN5A gene mutation is often associated with brugada
Phillipines, Japan, Thailand
How do we manage LQTS/Brugada?
- Long-term BB sometimes helps
- ICD Implantation is first-line and only proven preventative measure
- Avoiding QT prolongation meds
What is considered Unstable, acute, sustained VT and the treatment?
- Hemodynamically unstable
- Immediate DC cardioversion and ACLS
Unstable = hypotension, angina, AMS, or cardiac failure
Emailed her about the synchronized, and rice says synchronized is for monomorphic VT in which you can see a clear QRS and T wave. It is lower energy and is used to avoid shocking on the T wave, which could induce VF instead.
What are the first-line IV drugs for acute, sustained, hemodynamically stable VT?
- IV amiodarone to convert to NSR
- IV lido if refractory
- IV Mg replacement
How do you treat long-term VT?
- ICD
- BBs
- Class 3: Amiodarone or sotalol
- Catheter ablation
Prevents recurrence!
If a patient has nonsustained VT with no HD, what is the tx? With HD?
- Without HD, only treat with BBs if symptomatic.
- With HD, treat with BBs no matter what.
What is the leading cause of sudden death?
VF
Most people also have severe CAD.
How do you treat VF?
Immediate defibrillation
What is the primary artery related to LBBB?
LAD
When is LBBB considered emergent to treat?
Occurring in the presence of ACS symptoms
Assume it is an MI until proven otherwise.
or with reduced EF
What are the etiologies of LBBB development?
- Structural HD/ischemia
- Function (rate-related)
