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EP STUDYEQUIPMENTCATHETER PLACEMENTBASIC INTERVALS PERIODS

EQUIPMENT/PATIENT PREParation

EQUIPMENTRadiographic Table, Image intensifierSpecialized EP equipmentCardiac stimulatorDiagnostic and mapping cathetersData monitor and recorderRF energy generatorTemporary pacemaker, External pacemakerExternal DefibrillatorHemodynamic monitoringResuscitation equipment

PATIENT PREPARATIONStopping Anti-arrhythmics 2-3 daysFasting 6 hrsIV accessECG electrodes for 12 lead ECG and MonitoringExternal Remote Defib padsIndifferent skin electrode in RFAPulse Ox/NIBP/Invasive BPConscious sedation

EP Catheters

EP CathetersElectrode catheters are used during EP testing for recording and pacing.These catheters consist of insulated wiresAt the distal tip of the catheter, each wire is attached to an electrode, which is exposed to the intracardiac surface.Proximal end of the catheter, wire is attached to a plug, which can be connected to an external recording device Woven Dacron or polyurethane.

newer synthetic materials,6

EP CathetersDacronPolyurethaneAdvantage of stiffness that helps maintain catheter shape with enough softness at body temperature that allows formation of loopscannot be easily manipulated andchange shapes within the bodyexpensiveless expensive

EP CathetersElectrode catheters come in different sizes -2 to 10 Fr. In adults, sizes 5, 6, and 7 Fr catheters are the most commonly usedRecordings derived from electrodes can be unipolar (one pole) or bipolar (two poles).The electrodes are typically 1 to 2 mm in lengthThe interelectrode distance can range from 1 to 10 mm or moreCatheters with a 2- or 5-mm interelectrode distance are most commonly used

The greater the interelectrode spacing on a conventional bipolar electrode, the more the recorded electrogram resembles a unipolar recording.8

NUMBER OF ELECTRODES

4 3 2 1 2 (bipolar), 3 (tripolar), 4 (quadripolar), 6 (hexapolar), 8 (octapolar), 10 (decapolar), 20 (duodecapolar)

Electrode Orientation

EP CathetersLarge number of multipolar electrode catheters have been developed - facilitate placement of the catheter in the desired place and fulfill various recording requirements. Variety of preformed distal curve shapes and sizes.Multipolar recording electrode catheters are placed within the coronary sinus (CS) or along the crista terminalis in the right atrium (RA)Halo catheter is a multipolar catheter used to map reentrant electrical activity around the tricuspid annulus during RA macroreentry

Multipolar electrode catheters with different preformed curve shapes.

Multipolar electrode catheters with different electrode numbers and curve shape. , Duodecapolar catheter, quadripolar catheter, and Halo catheter.

A decapolar catheter with a distal ring configuration (Lasso catheter) is used to recordelectrical activity from the pulmonary vein.Basket catheters capable of conforming to the chamber size and shape have also been used for mapping atrial and ventricular arrhythmias

EP CathetersCatheters can have a fixed or deflectable tipSteerable catheters (deflectable tip) allow deflection of the tip of the catheter in one or two directions in a single plane; some of these catheters have asymmetrical bidirectional deflectable curvesRadiofrequency ablation catheters have three different tips: 4 mm, 8 mm, and a cooled tip (ranging between 3.5 mm and 5 mm)

Ablation catheters with different tip electrode sizes and shapes. Left to right, Peanut 8-mm, 2-mm, 4-mm, and 8-mm tip electrodes.Deflectable multipolar electrode catheters with different curve sizes and shapes.

Anatomy for epscatheter placement

Standard Catheter ElectrodesHigh RAQuadripolarFemoral routeTip - superolateral near SVC/RA junction

Standard Catheter ElectrodesRV apexQuadripolarFemoral routeTip as close to RV apex as possible

Standard Catheter ElectrodesCoronary SinusDecapolarEasiest access via SVC - IJV/SCV route

Standard Catheter ElectrodesHis BundleQuadripolar; 2-2-2Femoral routeTip straddles tricuspid annulus in its superior portion

Anatomy of RA

ComponentsRA appendageVenous partVestibule, inferiorly near TV annulusSeptum

Sulcus Terminalis / Crista separates RAA and venous part

Sinus node situated in the Sulcus terminalis at SVC RA junction

RAO view

Anatomy of RA - RAO view

BASIC EP Intervals and protocols

Right, The distal portion of the CS is closer to the ventricle (originating as great cardiac vein on the anterior wall); the CS crosses the atrioventricular (AV) groove at the lateral margin and becomes an entirely atrial structure as it empties into the right atrium (RA).Left,Thus, proximal CS recordings show large atrial and small ventricular signals, whereas more distal recordings show small atrial, large ventricular signals.

MEASUREMENT OF CONDUCTION INTERVALSRange of screen or paper speed generally used is 100 to 400mm/secTo evaluate sinus node function 100mm/sec is adequateRoutine refractory period studies require slightly faster speeds (150 to 200mm/sec)For detailed mapping of endocardial activation paper speeds of 200mm/sec or more should be used.Accuracy at 100mm/sec is approx 5msecAccuracy at 400mm/sec is approx 1msec

P Wave-Atrial IntervalThe P wave-atrial interval is measured from the first evidence of sinus node depolarization, whether on the intracardiac or surface ECG, to the atrial deflection as recorded in the HB lead. It represents conduction through the RA to the inferoposterior interatrial septum (in the region of the AVN and HB).The normal range of the PA interval is 25 to 55 millisecondsRarely, diseased atrial conduction can underlie first-degree AV block, indicated by a prolonged PA interval. A short PA interval suggests an ectopic source of atrial activation.

AtrialHis Bundle IntervalThe AH interval is measured from the first rapid deflection of the atrial deflection in the HB recording to the first evidence of HB depolarization in the HB recordingIs an approximation of the AVN conduction time, because it represents conduction time from the low RA at the interatrial septum through the AVN to the HB.The AH interval has a wide range in normal subjects (55 to 125 milliseconds) and is markedly influenced by the autonomic nervous system

ASSESSMENT OF H-V INTERVALTime from depolarization of proximal His bundle to the onset of ventricular depolarization ranges from 35 to 55 msec.NOTE- RBB deflection invariably occurs 30msec or less before ventricular activation. Thus , during sinus rhythm an apparent His deflection of less than 30msec either reflects recording of a bundle branch potential or the presence of preexcitation.Shorter than 35msec an accessory pathway is usually present producing ventricular preexcitation during sinus rhythm.Prolonged H-V interval longer than 70msec suggest a possible AV blockMore than 100 msec is severe abnormalitry and warrants permanent pacemaker

50

55

56Drive train with a single extra stimulus

56Coupling interval

57

Extra stimuli

S1S1S1S1S1S1S1S1S2SensedDRIVETRAIN

S1S1S1S1S1S1S1S1S2SensedDRIVETRAIN

S3

singledoubletriple

57Coupling interval: time between extra stimui (S2) after train pacing

Sinus Node Recovery TimeIt is the interval measured in the HRA from the last paced complex to the first spontaneous complex after the cessation of pacingEvaluate the effect of overdrive suppression on sinus node automaticity

When corrected for the underlying baseline sinus cycle lengthCSNRT = SNRT SCL

Pacing at several cycle lengths (e.g. 600, 500, 400, 350, 300)Reasonable values: maximum SNRT < 1500 ms maximum CSNRT < 550 ms

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SNRT:1180 CSNRT: SNRT- SINUS CYCLE LENGTH = 400

61Pacing 600Eigen sr 780 zelfde als voor pacingSNRT: 1180CSNRT: 400 Normal sinusnode function

SACT- defined as the conduction time between sinus node and the adjacent atrial tissue

A2A3 = A1A1 + 2 X SACT

SACT =(A2A3-A1A1) / 2

Ref. val. 50-115 ms

TO BE CONTINUED.

.NEXT presentationsBasic EP protocolsAtrial arrhythmiasVentricular Pre-excitation and AVRTVentricular arrhythmiasCatheter ablation