EP catheters

By Lenny Organ • May 22, 2025 • Tags:EP, recycling, electrophysiology, catheter, reprocessing

The basic components and function of electrophysiology (EP) catheters used in electrophysiology (EP) studies is the following:


  • Purpose: These specialized catheters are crucial for both recording the electrical activity of the heart and delivering pacing signals during EP studies. 
  • Structure:
  • Insulated Wires: The core of the catheter consists of multiple insulated wires.
  • Distal Electrodes: At the tip of the catheter, each wire connects to an electrode that makes direct contact with the heart's internal surface.
  • Proximal Plugs: The other end of each wire connects to a plug that interfaces with external recording and pacing equipment. 
  • Materials:
  • Dacron: A woven fabric known for its stiffness, which provides good structural support for the catheter. This stiffness is crucial for maintaining the desired shape of the catheter within the heart chambers. However, Dacron also exhibits sufficient flexibility at body temperature to allow for the creation of loops and curves as needed during the procedure. 
  • Synthetic Materials (e.g., Polyurethane): These materials are generally less expensive than Dacron and can be used to create smaller diameter catheters. However, they may be less flexible and more difficult to manipulate within the heart chambers.
  • Torque Control: Some manufacturers incorporate braided metal strands within the catheter structure. These strands enhance torque control, allowing for more precise steering and maneuvering of the catheter within the heart. 
  • Catheter Sizes:
  • Catheters come in a range of sizes, typically measured in French gauge (Fr). 
  • Common sizes for adult patients are 5 Fr, 6 Fr, and 7 Fr. 
  • The size of the catheter is crucial as it influences its ability to navigate through blood vessels and reach the desired location within the heart.
  • Electrode Types:
  • Unipolar: These electrodes have a single recording point.
  • Bipolar: These electrodes have two recording points separated by a specific distance. 
  • Electrode Dimensions:
  • Length: Electrodes are typically 1-2 mm in length.
  • Inter-electrode Distance: In bipolar electrodes, the distance between the two recording points can vary from 1 mm to 10 mm or more.
  • Recording Characteristics:
  • The inter-electrode distance significantly influences the recorded electrogram. 
  • In bipolar electrodes, a larger inter-electrode distance tends to produce recordings that more closely resemble those obtained from unipolar electrodes.
  • Common inter-electrode distances for bipolar catheters are 2 mm and 5 mm.


These design considerations ensure that electrode catheters can effectively record the heart's electrical activity with the necessary precision and accuracy for diagnostic and therapeutic purposes during EP studies.

  • Multipolar EP Catheters


 Purpose:

  • Multipolar catheters are designed to improve catheter placement and enhance recording capabilities.
  • They are particularly useful for recording and pacing from specific locations within the heart's chambers, such as the atria and ventricles.

 Features:

  • Bipolar or Quadripolar: These catheters have multiple electrodes, allowing for more precise recordings and more targeted pacing.
  • Variety of Shapes: They come with a range of preformed distal curve shapes and sizes, enabling them to navigate the complex anatomy of the heart and reach specific target areas.


By incorporating multiple electrodes and offering a variety of shapes, multipolar catheters provide greater flexibility and versatility during EP procedures, improving diagnostic accuracy and therapeutic efficacy.


 Placement:

  • Multipolar recording catheters are commonly placed within the coronary sinus (CS) or along the crista terminalis in the right atrium (RA). These strategic locations provide valuable information about the heart's electrical activity.

 Halo Catheter:

  • This specialized multipolar catheter is designed to map atrial electrical activity around the tricuspid annulus.
  • It is particularly useful for diagnosing and treating atrial tachycardias and identifying right-sided bypass tracts.


 Lasso Catheter:

  • This decapolar catheter features a distal ring configuration.
  • It is primarily used to record electrical activity from the pulmonary veins, which are often involved in the initiation of atrial fibrillation.



  •  Basket EP Catheters
  • These innovative catheters are designed to conform to the shape of the heart chambers.
  • This flexibility allows for more complete and accurate mapping of atrial and ventricular arrhythmias, providing valuable information for targeted ablation procedures.
  • Special Catheters for LA and LV Epicardial Activity:
  • Some specialized catheters are specifically designed to record electrical activity from the epicardium (the outer layer) of the left atrium (LA) and left ventricle (LV).
  • These catheters are often advanced through branches of the coronary sinus (CS) to achieve this.


These specialized catheter designs demonstrate the ongoing advancements in EP technology, enabling more precise and comprehensive mapping of cardiac arrhythmias and improving the success rates of ablation procedures.


  • Fixed vs. Deflectable Tips:
  • Fixed Tip: These catheters have a rigid tip that cannot be easily manipulated.
  • Deflectable Tip: These catheters allow for controlled bending of the tip, enabling better navigation within the heart chambers.
  • Steerable Catheters: These catheters allow for tip deflection in one or two directions within a single plane, providing greater maneuverability.
  • Asymmetrical Bidirectional Deflectable Curves: Some steerable catheters have more complex tip designs, allowing for even greater flexibility and control during navigation.
  • Ablation Catheters:
  • These catheters are specifically designed for ablation procedures, which involve the destruction of abnormal heart tissue to correct arrhythmias.
  • Tip Electrodes: Ablation catheters typically have larger tip electrodes compared to standard recording catheters.
  • Size: Ablation catheter tip electrodes can range from 4 mm to 10 mm in length.
  • Impact of Large Tip Electrodes:
  • The larger size of ablation catheter tip electrodes can reduce the resolution of electrical recordings obtained from the distal pair of electrodes.
  • This is because the larger electrode area may "average out" the electrical signals from a wider area of the heart tissue, making it more difficult to pinpoint the exact source of the arrhythmia.


These design features of catheters have significant implications for the success and accuracy of EP procedures, influencing the ability to navigate the heart chambers, record electrical activity, and deliver effective ablation therapies.