Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Hamra-Arrhythmias
Hamra Lecture 3- Arrythmias
| Question | Answer |
|---|---|
| Arrythmia | an abnormality of impulse initiation, impulse conduction or both |
| SA node rate of pacemaking | 60-100 bpm |
| AV junction rate of pacemaking | 40-60 bpm |
| Purkinje fibers | 20-40 bpm |
| Tachycardia | >100 bpm |
| Bradycardia | <60 bpm |
| Abnormal automaticity | Arrythmia associated with non-pacemaker cells that develop automaticity |
| Triggered activity | Oscillations in membrane potential that trigger an action potential |
| Sinus arrythmia | Inspiration causes an acceleration and Expiration causes a deceleration, NORMAL |
| Abnormal automaticity depolarizes tissues by | inactivating fast Sodium channels |
| Can you overdrive suppress abnormal automaticity? | NO |
| Early afterdepolarization can lead to a | Torsades de pointes |
| Delayed afterdepolarization leads to a | ITI- Calcium driven, transient inward current |
| 1st degree block | Consistent prolongation of the PR interval but all impulses get through. |
| Two types of 2nd degree block | Wenckebach (also MobitzI) and Mobitz (also called MobitzII) |
| Wenckeback | Progressive prolongation through the AV node with an eventual dropped beat----prolonged PR interval |
| Mobitz | Dropped beats without prolongation of the PR interval |
| Wenckebach reflects an abnormality in which region? | AV node |
| Mobitz reflects an abnormality in which region? | His bundle and/or bundle branches, usually an anatomical lesion and much worse! |
| 3rd degree block | Complete block through the AV node and another latent pacemaker takes over |
| What can cause an AV block | Increased vagal tone, Calcium channel block, Beta-blocker, Digitalis, Hyperkalemia |
| Re-entry | An arrhythmogenic mechanism in which the impulse does not die out but instead continues to circulate and re-excite tissue |
| Conditions for re-entry to occur | Unidirectional block, Slowed conduction over an alternate pathway, Re-excitation of tissue proximal to the block |
| Re-entry is promoted by things that | Slow conduction velocity, shorten the refractory period or a combination of both |
| Wolf-Parkinson-White syndrome | Patients have an accessory pathway that uses Sodium channels (fast!) instead of the normal Calcium channels (slow) used by the AV node- causes premature excitement and tachycardia |
| Wolf-Parkinson-white EKG | Delta wave, retrograde P waves and wdie QRS intervals |
Created by:
mcasto
Popular Medical sets