What is a drive train?
A sequence of paced beats (usually 8 or 9 pulses) to stabilise the refractory period of the heart, which will then allow you to use methods (extrastimuli) to induce VT/VF. Usually S1.
Can also be used to check sinus node recovery times and for termination or entrainment of arrhythmias.
What is a normal HV interval and what does it represent?
35-55ms. It represents the conduction time of the his-purkinje system.
What is a normal AH interval and what does it represent?
50-120ms. It represents the conduction of the AV node.
What is the definition of ERP?
The longest coupling interval in which a impulse fails to propagate through tissue.
What are the class I indications for EP testing?
Symptomatic but undocumented ?SA node or AV node disease, AV node block pacer patients that are still symptomatic, ?intraventricular conduction defects, tachyarrhythmias that aren’t responding to drugs, cardiac arrest survivors WITHOUT new Q wave, VT
What strength impulses do EP labs use?
Usually 2x but sometimes 4x the diastolic threshold, with a pulse duration of 1 to 2 seconds.
What would an AH jump indicate?
Dual AV nodal physiology/possibility of accessory pathway. Seen as an increase in the AH interval after a delivered extrastimulus.
What is entrainment?
Pacing and getting into the loop of an arrhythmia.
What is a VAV response and what would it indicate?
When pacing(?) the ventricle, you’ll see an atrial signal, and then the next beat in the arrhythmia will be a V, indicating the arrhythmia is dependent on the AV node/ if the arrhythmia ends in an A this is likely an AV node dependent tachy.
What would a VAAV response indicate?
If you pace(?) the V, and you see two consecutive A signals before the next V, you know that arrhythmia is originating in the atrium and does not require the AV node for facilitation.
Where does typical atrial flutter travel around?
Anticlockwise round the tricuspid valve.
What is a focal arrhythmia and can you entrain them?
Focal arrhythmia is one originating from one single focus area. You cannot entrain these.
