Exam (elaborations)
CCDS IBHRE EXAM QUESTIONS AND VERIFIED ANSWERS
- Course
- Institution
CCDS IBHRE EXAM QUESTIONS AND VERIFIED ANSWERS...
[Show more]
Seller
Follow
luzlinkuz
Reviews received
Content preview
CCDS IBHRE EXAM QUESTIONS ANDVERIFIED ANSWERS
Rheobase is the lowest point on a strength-duration curve with an endlessly long
pulse duration.
Chronaxie time - Determine the pulse width at twice the rheobase value. It
approximates the optimal stimulation pulse duration.
Charge (formula): ANSWER Charge= I(current) x T(time)
Furman's formula: Energy (microjoules) = I (current) x V (voltage) x T (pulse
width).
ANSWER Voltage (electromotive force) = I (current/flow of electrons) x R
(resistance to current flow in ohms).
The coupling interval that causes a detectable delay in impulse conduction is
known as the functional refractory period.
The effective refractory period is the longest coupling interval associated with a
block.
Devices that do not interact with pacemakers - ANSWER 1. Microwave oven,
2. CT/Ultrasound 3. X-ray (diagnostic)
Devices that generate temporary or one-beat inhibition: ANSWER 1. EAS 2.
Cellphones: 3. Arc Welding 4. Airport metal detector 5. TENS 6. Electric
appliances, including electric blankets and power tools
Devices that could harm the pacemaker - ANSWER 1. MRI 2. Defibrillator 3.
Cardioversion 4. Cautery/RF ablation 5. Radiation Therapy
Resistance in Series - ANSWER Series means that the start of one resistance is
connected to another.
,Add the resistances: R1 + R2 = total resistance. EX: A LEAD FRACTURE
(fractures increase impedance).
Resistance in Parallel - ANSWER: Parallel indicates that all resistances are
connected to the same place.
(R1xR2)/(R1+R2) equals total resistance.
EXAMPLE: LEAD INSULATION faults (insulation faults reduce impedance).
Are permanent pacemakers based on continuous voltage or current? -
ANSWER: All permanent pacemakers are constant voltage devices.
Some temperature pacemakers are constant voltage, but the majority are
constant current.
LOAD - ANSWER Load is the impedance (or resistance) applied to a circuit.
A system with a SMALL load (low impedance) applied to the circuit is called a
constant current device.
A system with LARGE load is described as a constant voltage device.
Guidelines for Permanent Pacing: ANSWER 1. Patient is symptomatic.
2. The heart rate is less than 40 bpm.
3. Asystole of more than three seconds is documented.
NOTE: The patient may be asymptomatic with two or three
Slew rate equals the peak slope of an electrogram.
Slew rate = change in voltage/change in time.
Normal slew rate in the atrium - ANSWER >.3 V/s
Normal slew rate in ventricle - ANSWER >.5 V/s
,The steroid utilised in electrodes is dexamethasone sodium phosphate in the
silicone core (a corticosteroid).
Steroid-Eluting Electrodes: ANSWER 1. The acute threshold is quite flat when
compared to non-steroid electrodes.
2. The initial capture threshold is comparable to non-steroid leads.
Pros of Silicone Rubber Lead Insulation: ANSWER 1. Can be readily repaired
2. Flexible
3. Proven performance history.
4. Easy to create.
Cons of Silicone Rubber Lead Insulation: ANSWER 1. High friction
coefficient.
2. Absorbs lipids.
3. More thrombogenic and fibrotic.
4. Cuts easily.
5. Tears readily if suture is tied too tightly.
6. Large diameter.
Polyurethane 80A - Bad Answer
Polyurethane 55D - ANSWER GOOD
Pros of polyurethane lead insulation: ANSWER 1. largely nonthrombogenic and
fibrotic.
2. Thin walls.
3. High tear friction.
4. resists cutting.
5. Low friction coefficient.
Cons of polyurethane lead insulation: ANSWER 1. Cannot be repaired.
2. relatively stiff
3. difficult to make.
Pacemaker Syndrome Causes: ANSWER 1. Loss of audiovisual
synchronisation
2. Sustained retrograde conduction
, 3. When exercise requires rate modulation, a single ventricular rate is used.
About 25% of individuals who are just paced from the ventricle may have some
degree of severity due to pacemaker syndrome.
Pacemaker syndrome diagnosis - ANSWER 1. Observe fluctuations in
peripheral blood pressure.
2. Cannon "A" wave at the neck
3. History alone
Pacemaker Syndrome Management - ANSWER Restore AV Synchrony
In ventricular alone PM, lower the pacing rate to minimise ventricular only
pacing.
Do not increase the pacing rate.
Fallback: ANSWER 1. Decouples atrial and ventricular events at the upper rate
limit.
2. The ventricular inhibited pacing rate eventually decreases to a predetermined
lower or "fallback" rate over a programmed duration.
3. When the fallback rate is met, atrial synchronisation is re-established.
Rate smoothing: ANSWER 1. Large cycle to cycle changes were eliminated by
limiting the paced rate from altering more than a specific percentage (3%, 6%,
12%, etc) from one V-V interval to the next.
2. Eliminates substantial swings in rates during fixed-ratio or pseudo-
Wenckebach blocks.
FOUND IN GDT Devices
sensor upper rate behaviour - ANSWER If the sinus rate is faster than the sensor
indicated rate, P synchronous pacing takes place.
If the sensor indicated rate is faster, AV pacing at the sensor indicated rate takes
place.
Mixed scenario: After a few cycles of sensor-driven AV pacing, a sinus rate
arises that is quicker than the sensor-indicated rate. The sensor-driven atrial
output will be blocked, a PR interval will begin, and ventricular output will
occur at the end of the sensor-AV interval. The ventricular rate will be equal to
the sensor-indicated rate, but the PV interval may be greater than expected.
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller luzlinkuz. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for CA$17.95. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
75759 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now