IBHRE EXAM STUDY QUESTIONS AND ANSWERS 2024 GRADED A

ICD Battery Types - 1. Li/SVO: Lithium/Silver-Vanadium Oxide (1st gen.) 2. Lithium/Manganese Dioxide (2 manufacturers) 3. Lithium/Silver-Vanadium Oxide-Carbon Monofluoride (2 manufacturers -MDT) Capacitor Types - -Aluminum Electrolytic -Tantalum 5 Phases of Cardiac Action Potential - *Phase 0: influx of Na+ (depolarization - conduction velocity) *Phase 1: transient efflux of K+ (how quickly the cell can be depolarized again) *Phase 2: influx of Ca 2+ & Na+ (") *Phase 3: efflux of K+ > influx of Ca2+ & Na+ (") *Phase 4: Na+ -K+ pump (resting phase, ion leakage determines when next spontaneous depolarization will happen) Excitable Periods of Cardiac Action Potential - Phase 0, Phase 1, Phase 2 Refractory Periods of Cardiac Action Potential - Phase 3 & Phase 4 Drugs That Increase DFTs - Lidocaine, Mexiletine, Flecainide, Quinidine, Disopyramide, Moricizine, Propranolol, Verapamil, Amiodarone, Sildenafil Citrate Drugs That Decrease DFTs - Sotalol, Dofetilide, Ibutilide Drugs With Conflicting Data on DFTs - Procainamide, Propafenone, Bretylium Drugs That Increase Pacing Thresholds - Flecainide, Propafenone, Encainide, Sotalol, Beta Blockers, Lidocaine, Verapamil, Procainamide Drugs That Decrease Thresholds - Atropine, Catecholamines, Glucocoticoids Drugs That Have No Proven Effect on Thresholds - Amiodarone, Anesthetic Drugs Name of Class 1 Antiarrhythmic Drugs - * 1a: disopyramide, procainamide, quinidine *1b: lidocaine, mexiletine *1c: flecainide, propafenone Class 1 Antiarrhythmic Drugs - Sodium Channel Blockers Name of Class II Antiarrhythmic Drugs - metoprolol, atenolol Class II Antiarrhythmic Drugs - Beta-blockers Name of Class III Antiarrhythmic Drugs - amiodarone, sotalol, ibutilide, dofetilide, dronedarone Class II Antiarrhythmic Drugs - Potassium Channel Blockers Name of Class IV Antiarrhythmic Drugs - verapamil, diltiazem Drugs Affect on Each Phase of Action Potential - *Phase 0: Class I - Na+ Channel Blocker *Phase 2: Class IV - Ca+ Channel Blocker *Phase 3: Class III - K+ Channel Blocker *Phase 4: Class II - Beta Blocker Shocking Vectors (MDT vs. Others) - B>AX = - > ++ AX> B = -- > + B>A = - > + A>B = -> + Laser Lead Extraction - 1. Locking stylet introduced down lead lumen & advanced to tip 2. Traction force directed to tip of lead and to aid in support 3. External outer sheath with beveled edge can be used over laser catheter for more direct passage of adhesion into laser Limitations to Laser Lead Extraction - - Fractured lead may prevent stylet passage - Stylet dislocation with high force - Adherent calcification cannot vaporize - Insulation damage or externalized conductors can hinder tracking the laser over catheter over - Risk of myocardial injury/perforation Mechanical Lead Extraction - - Mechanical dilator sheath over the lead - Uses rotational and reciprocating motion of internal cutting tool to chew fibrous adhesion - Lead pulled thru distal end of sheath w/manual traction Limitations for Mechanical Lead Extraction - - Works better for fewer adhesions - Most of the fibrous tissue still insitu and can obstruct further advancement of sheath - Calcifications - Potential to damage lead next to it Auto Adjusting Sense - *(VS) threshold starts at 75% of VEGM peak *(VP) threshold starts at end of VB & 4.5x the sensitivity value