Term
| what are the ions in fast channels |
|
Definition
|
|
Term
| what are the ions in slow channels |
|
Definition
|
|
Term
| what is membrane responsiveness determined by in slow response cells |
|
Definition
|
|
Term
| What is the Vmax at more negative potentials? |
|
Definition
| Higher. B/c more channels are in resting state and available for activation |
|
|
Term
| What is the relationship b/t Vmax and conduction velocity? |
|
Definition
| higher Vmax increases conduction velocity |
|
|
Term
| What is diastolic depolarization a dominant feature of? |
|
Definition
|
|
Term
| relationship b/t ERP and AP duration |
|
Definition
| proportional. b/c inactivation of Na channels is rapid and closely parallels repolarization |
|
|
Term
| where are fast response cells located |
|
Definition
atria
ventricles
HIS-Purkinje system |
|
|
Term
| what are the inhibitors of depolarization in Fast response cells |
|
Definition
|
|
Term
| Where are slow response cells located |
|
Definition
|
|
Term
| What are the inhibitors of depolarization in slow response cells? |
|
Definition
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|
Term
| Effect of catecholamines on slow response cells |
|
Definition
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|
Term
| Three main mechanisms of arrhythmia generation |
|
Definition
enhanced automaticity
triggered automaticity
re-entry |
|
|
Term
|
Definition
Interrupted repolarization
***major cause of Torsades de Pointes**** |
|
|
Term
|
Definition
Ca overload from MI
digitalis toxicity
rapid heartbeat |
|
|
Term
|
Definition
Quinidine, Procainamide, Disopyramide
**Queen Proclaims Diso's pyramid** |
|
|
Term
| characteristics of all Class 1 drugs |
|
Definition
decrease Vmax
decrease phase 4 diastole
increase threshold to conduct AP |
|
|
Term
| Therapeutic use of class 1A |
|
Definition
atrial flutter and fibrillation
V-tach and fibrillation |
|
|
Term
| side effects of Quinidine |
|
Definition
1A drug
**severe GI effects**
**headaches and tinnitus**
inhibits p450 metabolism
reduces clearance of digitalis |
|
|
Term
| This drug causes a reversible lupus like syndrome |
|
Definition
|
|
Term
|
Definition
Lidocaine, Mexiletine, Tocainide
*I'd Buy Lidy's Mexican Tacos* |
|
|
Term
| EP effect of Class 1B drug |
|
Definition
block Na channels more efficiently in diseased rapidly firing cells
increase K channel opening- shorten AP AND ERP |
|
|
Term
| Side effects of Class 1B drug |
|
Definition
|
|
Term
| Therapeutic use for class 1B drug |
|
Definition
Acute V-tach POST MI
IV push/drip |
|
|
Term
|
Definition
| Fecainide Encainide, Propafenone |
|
|
Term
| Contraindication of IC drug |
|
Definition
| Pro-arrythmic AFTER MI!!! |
|
|
Term
| Therapeutic use of 1C drug |
|
Definition
| Atrial and ventricular Tach |
|
|
Term
|
Definition
|
|
Term
| EP effects caused by Beta blockers |
|
Definition
comp. inhib w/Norep in heart
slow rate of depol.
**NO effect in presence of catecholamines** |
|
|
Term
|
Definition
K channel blockers
Amiodarone and Sotalol |
|
|
Term
|
Definition
increases AP duration and ERP
modest Na and Ca blocker effect |
|
|
Term
| This drug non competitively antagonizes a and b adrenergic receptors |
|
Definition
|
|
Term
| Major side effects of Amiodarone |
|
Definition
Pulmonary
Thyroid
Liver toxicities |
|
|
Term
| Therapeutic use fro Class 3 agents |
|
Definition
| **resistant** Atrial and vent. tachycardias |
|
|
Term
| Class 3 drug w/ Beta blocker effect |
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
decrease rate of dia depol
decr Vmax in SA and AV node
incr. threshold |
|
|
Term
| therapeutic use of class IV drugs |
|
Definition
PAT
atrial flutter and fib
Nodal arrhythmia |
|
|
Term
|
Definition
| reduces contraction in AV node due to vagal activity |
|
|
Term
|
Definition
|
|
Term
|
Definition
IV torsades de pointes
V-tach |
|
|
Term
| What is labetalol used for? |
|
Definition
it blocks a1 receptors in addn to b1 and 2
Chronic HTN |
|
|
Term
| Caution of beta blocker therapy |
|
Definition
| watch DM pts b/c beta's will mask the symtptoms of a hypoglycemic episode |
|
|
Term
| why are beta blockers used w/diuretics? |
|
Definition
| to prevent reflex tachycardia |
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