Term
|
Definition
| Force (potential) causing electron movement; Higher voltage indicates a stronger ―push/pull‖ of electrons; Unit of measure: Volts (V) |
|
|
Term
|
Definition
| Flow of electrons within a completed circuit path; Unit of measure: Ampere (amp) or miliamperes (mA); 1 amp = 1000 mA; Electrical symbol: I |
|
|
Term
|
Definition
| Opposition to current (also referred to as impedance); Unit of measure: Ohm ; Electrical symbol: R or ; Typical range: 300 – 100 Ohms |
|
|
Term
|
Definition
| Fundamental unit of work; Product of voltage, curent, pulse duration (pulse width); Unit of measure: micro Joules (J) ; J = 1000 mJ = 1,000,000 J ; Electrical symbol: E |
|
|
Term
|
Definition
–Chamber paced
–Chamber sensed
–Response to sensing
–Rate modulation |
|
|
Term
|
Definition
| Contains the power source (battery) and the electronic circuitry necessary for operation of the device |
|
|
Term
|
Definition
| Ability of the device to sense and respond to the electrical activity of the heart |
|
|
Term
|
Definition
Any unwanted signal or noise sensed by the device
•May originate from:
–Electromagnetic interference (EMI)
–Myopotentials
–Tall P or T waves. |
|
|
Term
| Factors affecting resistance |
|
Definition
-Lead insulation break
-Lead fracture
-Fracture of the lead wire, increases resistance and decreases current flow |
|
|
Term
|
Definition
| Normally 0.5 msec in permanent pacers and 2 msec in temporary pacers. |
|
|
Term
| Battery size in pacemakers |
|
Definition
| Usually 5 volts in permanent pacemakers and 15 volts in temporary pacers. |
|
|
Term
| Minimal electrical energy required to consistently capture the heart outside the refractory period. |
|
Definition
|
|
Term
| How is the Stimulation Threshold measured |
|
Definition
measured at a pulse width of 0.5 msec
(always in volts) |
|
|
Term
| The stimulation threshold is at its lowest when? |
|
Definition
|
|
Term
| Peak Stimulation Threshold occurs when? |
|
Definition
| 2 to 6 weeks after implant |
|
|
Term
|
Definition
| Occurs when the stimulation threshold exceeds the output of the pulse generator. |
|
|
Term
| What will epinephrine do to the stimulation threshold? |
|
Definition
| it will lower the threshold |
|
|
Term
|
Definition
The total height (both positive and negative deflection) in millivolts of the intracardiac signal.
AKA:
•Intrinsic deflection (ID) - the peak-to-peak deflection of the intracardiac signal as sensed by the pulse generator.
•The greater the amplitude or ID, the more likely it will be sensed.
•Usually only measurement sufficiently required for determining sensitivity. |
|
|
Term
| Usually only measurement sufficiently required for determining sensitivity. |
|
Definition
| Amplitude or Intrinsic deflection |
|
|
Term
|
Definition
| is the rate of change in voltage in an intracardiac electrogram and is mathematically represented by dv/dt. |
|
|
Term
| Factors affecting sensing |
|
Definition
–Lead maturation
–Lead dislodgement/penetration
–Ischemia
–Lead integrity/design
–Noise
–Drugs |
|
|
Term
| All Pulse Generators must have at least these two circuits |
|
Definition
|
|
Term
| Delivers a pulse at a constant preset rate, regardless of the intrinsic activity |
|
Definition
Asynchronous generator
-Also called a Fixed-rate generator |
|
|
Term
| Allows pacing and sensing circuit parameters to be changed non-invasively. |
|
Definition
|
|
Term
| Refractory periods (in pacemaker terminology) |
|
Definition
| refers to the brief period after a sensed or paced beat in which the sensing circuit does not sense. |
|
|
Term
| Ability to interrogate the pacemaker and receive a readout of the programmed parameters and the status of the pacemaker. |
|
Definition
|
|
Term
| Most commonly used dual chamber pacemaker. |
|
Definition
|
|
Term
| Transcutaneous pacing (TCP): |
|
Definition
–Also referred to as external cardiac pacing, noninvasive pacing, external transthoracic pacing, etc.
–Heart is stimulated with externally applied cutaneous electrodes that deliver an electrical impulse across the intact chest wall to the myocardium
•TCP consists of a external device connected to two electrodes with a cable/wire:
–One electrode placed on the right pectoral area next to the sternum (anterior) and one on the left scapular area (posterior).
–Also right pectoral area and the lateral portion of the chest wall (V5 or V6 position) may be used if access to the back is not feasible. |
|
|
Term
| Indicated in the treatment of hemodynamically significant bradycardia not responsive to atropine therapy. |
|
Definition
| Transcutaneous pacing (TCP) |
|
|
Term
| Indications for temporary pacing: |
|
Definition
–Hemodynamic compromising bradycardia.
–Bradycardia with escape rhythms unresponsive to drug therapy.
–Symptomatic 1st and 2nd degree type I Heart Block.
–2nd degree type II and 3rd degree heart block
–Overdrive pacing of refractory tachycardia.
–Newly acquired BBB in presence of acute MI.
–Prophylactic use during PTCA and right heart cath in patients with LBBB. |
|
|
Term
| How do you find the stimulation threshold with pacing? |
|
Definition
| Stimulation threshold is the last mA that captured before loss. use 2 to 4 times the stimulation threshold. |
|
|
Term
| Complications of temporary pacing |
|
Definition
–Hemothorax, pneumothorax, and thrombophlebitis.
–Malignant ventricular arrhythmia's.
–Myocardial wall perforation and cardiac tamponade |
|
|
Term
| ECG Guidance for placement of Temporary Pacemeakers -P wave |
|
Definition
•Large and inverted in SVC
•Biphasic in mid RA
•Small in RV
•Negative in PA |
|
|
Term
| ECG Guidance for placement of Temporary Pacemeakers -QRS segment |
|
Definition
•Small in RA
•Large in RV (ectopy common)
•ST segment: Will elevate when catheter is in contact with wall |
|
|
Term
| Advantages of transvenous pacemaker |
|
Definition
–Ease of insertion.
–Decreased morbidity/mortality.
–Decreased surgical trauma.
–Reduced recovery time. |
|
|
Term
| Disadvantages of transvenous Pacemaker |
|
Definition
–Exit block due to acute injury process
–Lead dislodgement. |
|
|
Term
| What is the most common approach in the packing community? |
|
Definition
| Endocardial Approach (Transvenous) |
|
|
Term
| Most common vessel for transvenous pacing lead? |
|
Definition
–Cephalic (most common)
–External jugular
–Subclavian
–Internal jugular
–Femoral (least common) |
|
|
Term
| When is acute stimulation threshold measured? |
|
Definition
|
|
Term
When is chronic stimulation threshold measured?
slide 96 |
|
Definition
| Performed 6 to 8 weeks post implant |
|
|
Term
| After finding your stimulation threshold, what should you then set the voltage output to? |
|
Definition
| The voltage output is then usually set 2 to 4 times higher than the measured threshold at implant to reduce the possibility of the pacer failing to capture due to fibrosis. |
|
|
Term
| For stimulation threshold Increased surface area equals: |
|
Definition
–Increased sensing
–Increased threshold
–Less resistance (for the current to flow). |
|
|
Term
| Current sensitivity standard for most implantable pulse generators is what? |
|
Definition
|
|
Term
| The peak to peak voltage of the ID, or amplitude, usually ranges from |
|
Definition
|
|
Term
| When unwanted signals such as T waves, P waves (unless pacing the atrium), EMI, pacemaker afterpotentials, myopotentials are sensed, the pulse generator is inappropriately inhibited. |
|
Definition
|
|
Term
| When the patient’s R wave as transmitted by the implanted lead does not display an amplitude that will inhibit the pulse generator. |
|
Definition
|
|
Term
| All functional parameters of the pulse generator should be analyzed prior to and after connecting to lead. |
|
Definition
–Rate in pulse per minute (ppm) and msec intervals
–Pulse width in msec
–Pulse output in both V and mA under a 500ohm load
–Pulse generator sensitivity
–Refractory periods following both sensed and paced beats
–Hysteresis |
|
|
Term
| If a pulsed magnetic field is transmitted, it can influence a piece of metal called a ______________ to complete an electrical circuit. |
|
Definition
|
|
Term
|
Definition
| Procedure by which direct current (DC) is delivered across the heart (transmyocardial current) for the purpose of converting unstable ventricular tachycardia or ventricular fibrillation to a sinus rhythm |
|
|
Term
| Most frequent rhythm seen in sudden cardiac death is what? |
|
Definition
|
|
Term
| Is a procedure by which direct current (DC) that has been synchronized to discharge with the QRS complex is delivered across the heart for the purpose of converting an supraventricular or unstable ventricular tachyarrhythmia to a sinus rhythm |
|
Definition
| Synchronized Cardioversion |
|
|
Term
| For synchronized cardioversion sedation is required unless what? |
|
Definition
|
|
Term
| Strength of defibrillation is most commonely expressed in? |
|
Definition
| energy (joules or watts-second) which is the product of power and duration |
|
|
Term
| For pediatrics... how many joules per point / per kg |
|
Definition
1 joule per pound
2 joules per kg |
|
|
Term
| Firm pressure of the electrodes will decrease transthoracic resistance by as much as what for defib? |
|
Definition
|
|
Term
| How much pressure due you apply to the electrodes for defib? |
|
Definition
| 11kg (25lb) for each electrode |
|
|
Term
| You should attach an External Defibrillator (AED) only to patients that weigh more than what? |
|
Definition
| 50kg or 110lbs because most AEDs have a minimum energy level of 200 Joules |
|
|
Term
| A device like a pacemaker which is simply an electrical circuit requiring a closed loop. The electricity is directed across a large portion of the myocardium in an effort to depolarize most of the ventricle. |
|
Definition
| Automated Implantable Cardiac Defibrillator |
|
|
Term
| Indications for Implantable Cardiac Defibrillator |
|
Definition
–Intended for the use of patients whom are at high risk for sudden cardiac death due to ventricular arrhythmias
–Incessant VT or VF that is not suppressed by medical, surgical, or other ablative therapy.
–Expanded for asymptomatic non-sustained VT with decreased ventricular function |
|
|
Term
| Contraindications to an ICD |
|
Definition
•Transient ventricular tachyarrhythmias due to reversible causes:
−Drug toxicity
–Electrolyte imbalance
–Sepsis
–Hypoxia
•Transient ventricular tachyarrhythmias due to other factors:
–Myocardial infarction
–Electrocution |
|
|
Term
| Defibrillation threshold (DFT) |
|
Definition
| is the lowest energy that successfully terminates ventricular fibrillation. |
|
|
Term
| What is the goal of DFT testing |
|
Definition
| The goal of DFT testing is to ensure that the maximal energy output of the device has an extremely high (> 99%) probability of terminating ventricular fibrillation in any given patient. |
|
|
Term
|
Definition
| How much power is delivered |
|
|
Term
|
Definition
| Precisely when the pacemaker impulse will be delivered to the myocardium |
|
|
Term
| Also called a Fixed-rate generator |
|
Definition
|
|
Term
|
Definition
–Monitors heart activity
–Acts as a receiver tuned only to wanted signals
•P waves—atria
•R waves—ventricles
–Other signals are discriminated against.
–Determines how the PG responds to a sensed depolarization
–May reset timing circuit during intrinsic heart activity
–May trigger the output circuit to pulse in synchrony with heart activity |
|
|
Term
| What are the pacemaker programmed parameters that you can check with telemetry? |
|
Definition
–Rate
–Pulse width
–Output
–Sensitivity
–Refractory periods |
|
|
Term
| Transcutaneous pacing pulse width is factory set. What is the range? |
|
Definition
|
|
Term
| What is the typical programmable range of beats per minute in a permanent pacemaker? |
|
Definition
30 to 120 bpm
•Most pacemakers are preset by the manufacturer at 60 to 70 bpm. |
|
|
Term
| When in the respiratory cycle is transthoracic resistance at its minimal? |
|
Definition
|
|
Term
| How does the duration of time in V-Fib affect electrical defibrillation? |
|
Definition
| The longer VF persists the less likely successful electrical defibrillation. |
|
|
