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