CCDS IBHRE Questions And Answers 100% Guaranteed Success.

CCDS IBHRE Questions And Answers 100% Guaranteed Success. Rheobase - correct answer. the lowest point on a strength duration curve at an infinitely long pulse duration Chronaxie time - correct answer. the pulse width at twice the rheobase value. It approximates the most efficient stimulation pulse duration Charge (formula) - correct answer. Charge= I(current) x T(time) Furman's formula - correct answer. Energy(microjoules)= I(current)xV(voltage)xT(pulse width) Ohms law formula - correct answer. Voltage(electromotive force)= I(current/flow of electrons) x R(resistance to current flow in ohms) Functional Refractory Period - correct answer. the coupling interval which first results in a measurable degree of delay in impulse conduction Effective Refractory Period - correct answer. the longest coupling interval to be associated with block Devices with NO interaction with pacers - correct answer. 1. microwave oven, 2. CT scan/Ultrasound 3. X-rays (diagnostic) Devices that cause transient or 1 beat inhibition - correct answer. 1. EAS 2. Cellphones 3. Arc Welding 4. airport metal detector 5. TENS 6. Electric appliances such as electric blanket & power tools Devices that may damage the pacemaker - correct answer. 1. MRI 2. Defibrillator 3. Cardioversion 4. Cautery/RF Ablation 5. Radiation Therapy Resistance in Series - correct answer. Series means the beginning of one resistance is connected to another Sum the resistances: R1+R2= total resistance. EX: A LEAD FRACTURE (fractures INCREASE impedance) Resistance in Parallel - correct answer. Parallel means all the resistances are connected to the same point. (R1xR2)/(R1+R2)= total resistance EX: LEAD INSULATION DEFECTS (insulation defects DECREASE impedance) Permanent pacemakers are constant voltage or constant current? - correct answer. ALL permanent pacemakers are constant voltage devices. SOME temp pacemakers are constant voltage, most are constant current. LOAD - correct answer. Load refers to impedance (or resistance) applied to a circuit. A system with a SMALL load (low impedance) applied to the circuit is said to be a constant current device A system with LARGE load is said to be a constant voltage device Guidelines for Permanent Pacing - correct answer. 1. Patient is symptomatic 2. The heart rate is less than 40 bpm 3. Asystole of greater than 3 seconds is documented NOTE: Pt may be asymptomatic with 2 or 3 Slew Rate - correct answer. Slew rate = peak slope of an electrogram slew rate= change in voltage/ change in time Normal slew rate in atrium - correct answer. >.3 V/s Normal slew rate in ventricle - correct answer. >.5V/s Steroid used in electrodes - correct answer. dexamethasone sodium phosphate in the silicone core(a corticosteriod) Steroid-Eluting Electrodes - correct answer. 1. The acute threshold is relatively flat compared to non-steroid electrodes 2. The initial capture threshold is similar to non-steroid leads Silicone Rubber lead insulation Pros - correct answer. 1. Can easily be repaired 2. Flexible 3. Proven performance history 4. Easy to make Silicone Rubber lead insulation cons - correct answer. 1. high friction coefficient 2. Absorbs lipids 3. More thrombogenic and fibrotic 4. Cuts easily 5. Tears easily if suture tied too tightly 6. Large diameter Polyurethane 80A - correct answer. BAD Polyurethane 55D - correct answer. GOOD polyurethane lead insulation pros - correct answer. 1. relatively nonthrombogenic/fibrotic 2. thin walls 3. high tear friction 4. resists cutting 5. low friction coefficient polyurethane lead insulation cons - correct answer. 1. cannot be repaired 2. relatively stiff 3. hard to make Pacemaker Syndrome Causes - correct answer. 1. Loss of AV synchrony 2. Sustained retrograde conduction 3. A single ventricular rate when rate modulation is required for exercise Approx 25% of patients only paced from the ventricle may have some level of severity related to pacemaker syndrome Pacemaker syndrome diagnosis - correct answer. 1. Observe fluctuation in the peripheral blood pressure 2. Cannon "A" wave in the neck 3. History alone Pacemaker syndrome management - correct answer. Restore AV synchrony in ventricular only PM -->lower the pacing rate to minimize ventricular only pacing DO NOT increase the pacing rate Fallback - correct answer. 1. Decouples atrial & ventricular events at the upper rate limit 2. The ventricular inhibited pacing rate then gradually decrements to a programmed lower or "fallback" rate over a programmed duration 3. When the fallback rate is reached, atrial synchrony is restored Rate smoothing - correct answer. 1. Eliminated large cycle to cycle variations by preventing paced rate from changing more than a certain percentage (3%, 6%, 12%, etc) from one V-V interval to the next 2. Eliminates large fluctuations in rate during fixed-ratio or psuedo-Wenckebach block FOUND IN GDT devices sensor upper rate behavior - correct answer. if the sinus rate is faster than the sensor indicated rate, P synchronous pacing occurs if the sensor indicated rate is faster, AV pacing at the sensor indicated rate occurs mixed scenario: when the device is sensor driven AV pacing for a few cycles and a sinus rate sudden emerges faster than the sensor indicated rate. The sensor driven atrial output will be inhibited, a PR interval started, and a ventricular output will occur at the end of the sensor AV interval. That is, the ventricular rate will be equal to the sensor indicated rate, but the PV interval may be longer than expected Medtronic Rate Drop Response - correct answer. 1. Increase in HR (Pacer is programmed to a top rate) 2. Rise in HR is immediately followed by a fall in HR. (pacer is programmed to a "bottom" rate 3.The HR drop must be identified, therefore a number of "Width" beats must be programmed the HR must fall to the bottom rate in fewer than the programmed "width" beats 4. To confirm the rate drop, a small number of confirmation beats must be programmed. The HR must remain below the bottom rate for this number of confirmation beats in order for the algorithm to activate Tilt Testing Results for RDR - correct answer. 1. An initial rise in the HR to a value at or above the "Top Rate" must occur 2. A rapid fall in HR must then follow 3. A fall in BP resulting in symptoms must occur next 4. Syncope should not occur until the HR has dropped by 20-30 bpm X-ray Exposure (formula) - correct answer. Exposure= exposure rate x time Longevity calculation - correct answer. longevity is usable battery in Amp Hours Pacer current drain = in micro amps hours in one year = 8760 hours Usable battery capacity/pacer current drain = # of hours Battery longevity (in yrs)= 114x(Ahr battery capacity)/(current drain in uA)=c Bisping Coaxial Lead - correct answer. Bisping is an extendable/retractable helix type lead. MDT owns the patent