[Music] welcome to this presentation on electrphysiology foundation session two now that we are familiar with arhythmia mechanisms we can discuss the indications for an EP study once an ECG documents particular rhythmas it may necessitate the need for further investigation with an invasive EP study a specialized cardiologist and electrphysiologist will perform the study the indications are broken into a few categories brad arrhythmias tachiarhythmias and ablation procedures it is important to note that typically studies are conducted on indicated rhythmas with symptotomatic patients bradymias will include sick sinus syndrome highgrade AV block and syncopy in patients with unknown eeteology and suspicion of structural heart disease tacureythmias will include SVT WPW VT any wide complex tacoc cardia with unknown origin and also sudden cardiac death survivors ablation procedures are conducted to aim at eliminating any of these arhythmias as well as atrial fibrillation or atrial flutter the category of bratty arhythmias refers to abnormally slow rhythms for the majority of patients exhibiting bratty arhythmias an ECG recording will document sufficient information for diagnosis and treatment where ECG data is nondiagnostic and more information is required an EP study will aid as a supplement to the analysis of the ECG these slow rhythms will originate from either a failure in impulse generation or impulse propagation failure of an impulse to be generated indicates an inadequate rate of deolarization emerging from the essay nodal pacemaker site this indicates a degenerative process within the SA node and classically we see marked sinus braticardia sino atrial paws arrest and sick sinus syndrome symptomatic patients will present with syninkable episodes that will warrant an EP study failure of impulse propagation will affect the normal conduction of impulses through the electrical pathway within this classification various levels of heart blocks within the AV node and his bundle are present ep studies will focus on symptomatic patients to determine if a block is the cause of the symptoms and to assess the sight and degree of the block through EP studies we can measure various intervals that will determine where the site of the block is if the block is located within the AV node a latent pacemaker will generate impulses at the AV junction to sustain a stable narrow complex escape rhythm firing at rates between 40 to 60 beats per minute blocks within the AV node are most often due to transient and acute conditions such as infuction rheumatic fever and AV nodal blocking drugs once you reverse the cause AV block identified within the AV node will often reverse to normal conduction if the block is identified distal to the AV node a permanent pacemaker will usually be the treatment when the block is located distal to the AV node the latent pacemaker will provide an unreliable unstable wide complex rhythm discharging at rates of 20 to 40 beats per minute this is not sustainable for proper cardiac function and is life-threatening to the patient this type of AB block is not reversible and chronic in nature we will shift the focus now into the EP lab and discover all the tools of the trade ep catheters are very specialized insulated wires that contain electrodes at the distal end and plugs at the proximal end to clarify the distal end of the catheter will be inside the heart and the proximal end with the plugs is towards the outside of the body ep catheters are similar to pacemaker lead wires but contain more electrodes usually there are four to 10 electrodes per catheter depending on the location the catheter is in we will learn the specific location of the strategically placed catheter in future slides the high right atrial catheter or HR the H and right ventricular apex or RVA catheter will usually have four electrodes and the coronary sinus or CS catheter will typically have 10 electrodes electrodes are arranged in pairs to record electrical activity or to deliver a stimulus or paste impulse the spacing of these electrodes will determine how localized the signal recorder will show and also the voltage potential of the signal additionally each electrode pair will have polarity and be recorded from negative to positive or electrode 1 to two remember that the recording will flow from distal to proximal when an EP study involves an ablation technique a specialized radio frequency ablation catheter is introduced in a standard SVT study only the HR and RVA catheters are used for pacing the H catheter is utilized only for recording signals and serves no function in providing any pacing stimulus at the proximal end of the catheters are plugs that will be connected into the junction box and amplifier this basically looks like a giant pegboard that you will plug in the various connector plugs to organize the recording electrodes the recording electrode pairs are recorded as bipolar signals and can be adjusted before and during the EP study to accommodate the desired signal the programmable stimulator is a device connected to the junction box capable of delivering constant pacing impulses to multiple locations within the heart as a means to stress the conduction system the stimulator has two roles during the EP study to provide pacing stimuli and act as a ba backup pacemaker if marked braticardia occurs during a procedure the physiologic recorder is a computer-based recording system that is designed to record all relevant intracardic recordings or EGM and has the capability to modify measurements from the EGMs through the use of electronic calipers signal gain and alterations in speed all data can then be stored in a hard drive and provide hard copy printouts the display screen can display up to 12 channels in all sorts of colors the 3D mapping system is a 3D electroanatomical navigation system that can graphically display cardiac structures and identify localization of arhythmias all in real time the images are an incredible tool for mapping locations of arrhythmias and aiding in ablations of these sites if required the use of 3D mapping has added benefits to the patient with a reduction of radiation exposure other equipment found in an EP lab would be the fllororoscopic unit and patient table and ACLS equipment during EP studies when introducing pacing stimuli with an unknown arrhythmia mechanism there are risks of life-threatening arrhythmias that can cause hemodnamic collapse the ACLS equipment will include a full crash cart and defibrillator in regards to staffing the EP lab at minimum staff would include the electrphysiologists two cardiac nurses and a technologist all trained in ACLS standards this image shows a very basic understanding of the various equipment in the EP lab and how it all connects together here is a more realistic photograph of an EP lab note the various equipment and again how it all connects together all we need is a patient and staff and we are ready to go the first step to an EP study is to fully prepare the patient patient consent will always be the first step to prepare for the test the patient should be in a fasting and baseline state withdrawal of all non-essential drugs and most importantly anti-arhythmia drugs preferably 2 to 3 days prior to the study due to the invasive nature of the study anxiety is typically seen and local anesthesia or conscious sedation is given to alleviate high levels of stress once the patient is brought to the EP lab in a fasting and baseline medication state the catheterization process will begin the EP lab is a sterile environment all catheterss are inserted by the selinger technique and often accessed by the femoral veins the upper extremities may be used for catheter insertion for complicated studies or where multiple catheters are required the fllororoscopic unit will then be used to guide the catheterss into their strategic locations within the heart the catheterss will then be plugged into the junction box to correspond the recording and pacing electrodes with the appropriate channels now the baseline recording of EGMs along with surface ECG tracings will begin approach for catheterization during EP study is through which vein the answer is the femoral vein as previously mentioned a simple diagnostic study could include only one catheter in the high right atrium and one catheter in the H position with more complex SVT studies the addition of the CS and right ventricular apex catheters are used the location of the hybrid atrial or HRA quadripolar catheter is in the high lateral wall near the junction of the superior vennea at approximately the SA node location two channels will usually be displayed from the HR catheter the distal channel using electrode pair 1 2 and the proximal channel using electrodes 34 both channels will record local sinus node activity pacing is typically delivered from the distal pair because it will be in best contact with the mocardium the coronary sinus or CS catheter is usually a decapolar or 10 electro catheter that can record five distinct EGMs it is guided through the coronary sinus osteium to record both left atrial and ventricular signals recording and pacing can now both be accomplished from the left side of the heart the H quadripolar catheter is located straddling the tricuspid annulus in the posterior aspect in the anatomic location of the AV node the H catheter can record activity from the low atrium AV node H bundle and the right ventricle this catheter will provide the most information about conduction through the AV node the right ventricular apex or RVA quadripolar catheter is positioned in the right ventricle close to the apex similar to the HRA catheter we will usually display a distal and a proximal RVA channel all RVA channels will record local activity from the right ventricular apex and all electrodes could be used to pace but pacing is typically delivered from the distal channel one two because it will be in best contact with the myioardium the radio frequency or RF catheter is only introduced when ablation is required and its location will vary depending on the site necessary to ablate what do these catheter labels stand for h R A stands for high right atrium cs for coronary sinus his for his bundle RVA for right ventricular apex and RF for radio frequency here we have fllororoscopic images of the location of EP catheters with an anterior posterior view and left anterior oblique view this image shows another view of catheter placement and the respective EGM and ECG recording signals relating the EGM to the surface ECG is essential to understanding the electrical conduction pathway the HRA catheter will record activity at the SA node and correlates to roughly the start of a Pwave on the surface ECG and shows only one waveform called an Awave the H or HB catheter records activity from the atrium AV node and right ventric ventricle and correlates to the PR interval and QRS on the surface ECG notice that the HB signal contains three distinct waveforms called A H and V waves the RVA records right ventricular activity and shows only one waveform called a Vwave that correlates with the QRS on the ECG the CS catheter is shown in the image but no corresponding recording signal is shown as we recall the CS catheter records activity from the left side of the heart in both the atrium and ventricle we have briefly discussed the use of the RF or radio frequency catheter used for ablation procedures catheter ablation has become an accepted treatment for atrial fibrillation the basic function of an RF catheter is positioning the catheter at a critical location to create a discrete scar in the mocardial tissue through the administration of alternating current that heats the tip of the catheter the RF catheter is introduced into the left atrium through a transeptal puncture approach the catheter can then output energy to create thermal lesions in the area surrounding the pulmonary veins this location has proven to be an area of high frequency atrial ectopy and electrical isolation of the pulmonary veins has become a cornerstone of any AIB ablation approach as with any invasive diagnostic procedure there are risks to be aware of the EP study is similar to heart catheterization and can cause vascular complications such as bruising hematas vascular damage throbo embolism infection and pumothorax the most notable complications are more severe and can cause AV nodal damage resulting in the need for a permanent pacemaker implant life-threatening arhythmia induction and cardiac tampenade can result from puncture of the mioardial wall that takes us to the end of this presentation on electrphysiology foundation session two [Music]