Arrhythmias Lecture Flashcards
How do you help someone with ventricular fibrillation (most common cause of sudden CV death)?
defibrillate and give them an automatic implantable cardiovertor defibrillator (AICD)
What complication is common with a fib?
stroke (prevent using anticoagulants like warfarin- not aspirin)
What is the significance of ventricular hypertrophy?
its a major risk factor for CHD- just as much as smoking, diabetes, etc.
R waves are very elevated
What do you see in an ECG with bundle branch block?
wide QRS complex almost always with abnormal T waves
Cant do a stress test on these patients
How to distinguish RBBB vs LBBB?
RBBB has a large R wave in v1
ECG of ischemia?
ST depresses below baseline and T wave inverted
What is the mechanism of enhanced automaticity?
alteration of phase 4 of the action potential causing spontaneous depolarization
What things could cause enhanced automaticity?
increased sympathetic tone, catecholamines, CO2 (COPD patients), acidity, temp, stretch, calcium
decreased parasym, potassium, or oxygen
What drugs can cause enhanced automaticity?
digoxin
What drugs can decrease automaticity?
anti-arrhythmics and BBs
T or F. Everyone has a fast and slow channel in their AV node
T. So they can have a re-entry arrhythmia
What is a junctional rhythm?
commonly seen in digitalis use where the P wave is gone and the conduction comes mostly from the ventricles
Multifocal atrial tachycardia is typically seen in patients with what?
COPD (classic example of enhanced automaticity)
What channels are involved in depolarization of the SA and AV nodes?
Na+ funny current and Ca2+, and is modified by catecholamines (BB), vagal (ACh) influence, and adenosine
What channels are involved in depolarization of the ventricles and atria (conducting tissue and myocytes,etc)?
Na+ and K+ channel dependent
What are the options for treating a fib?
rhythm control or rate control
RATE is better overall!!
What are the disadvantages of rhythm control?
- pro-arhythmic side effects of class I or III AAs
- stroke rates can actually be higher if not giving warfarin
- pulmonary events and bradycardia may be observed more often
What are the disadvantages of rate control?
- still have increased risk of stroke
- decreased atrial kick
- irregular ventricular action without atrial input actually reduces ventricular function and can indue heart failure
- patients typically have to be on warfarin which can cause bleeding
How can you ID PSVT?
narrow QRS, no P wave (no atrial activity), very tachycardic
