How To Build an EP Lab in 2008

In EP Lab Digest’s new “How To” section, articles will focus on one learning objective each month. Recent years have seen a rapid and steady increase in the number of patients undergoing interventional electrophysiology (EP) procedures. Several clinical trials have demonstrated the superiority of cardiac rhythm management devices for the primary prevention of sudden cardiac arrest in patients with reduced left ventricular function. Cardiac resynchronization devices have been shown to benefit many patients with heart failure. In addition, the advent and evolution of ablation therapy for the treatment of atrial fibrillation (AF) has resulted in the increase in the number and complexity of procedures in most EP labs. This has led to the addition of new labs in hospitals with established EP labs. Many hospitals that historically have not had EP facilities have seen advantages in constructing EP labs. This article will discuss some basic EP lab design issues, as well as review the equipment and technology currently used in most labs performing complex EP procedures. Design Issues Two of the initial issues to consider when designing a new EP lab are the number and size of the labs. The issues that determine the number of labs needed are: the number of electrophysiologists performing procedures, the expected volume of cases, the complexities and duration of the cases, and whether device implantations will take place in the lab. AF ablations can be lengthy procedures, and can make scheduling of other cases challenging if only one room is available. Many hospitals have seen the need to build two labs, with one designed for complex mapping and ablation cases, and one primarily used for device implantations. In addition, some EP departments have built smaller rooms without fluoroscopy equipment for tilt studies, cardioversions, or other non-invasive procedures. The size requirement of the lab is determined by the types of cases to be performed and the necessary equipment. Biplane fluoroscopic imaging typically requires a larger lab than with single-plane fluoroscopy, due to the storage area needed when the lateral tube is not in use. Adequate space should also be available for sedation and/or anesthesia equipment and personnel at the head of the fluoroscopy table. Some established EP labs have seen advantages to having a separate control room for the EP recording system and other equipment. Other labs have the “cockpit” in the lab itself, usually set up on a desk or console. Separate control rooms allow for EP staff to perform some duties without exposure to radiation from the fluoroscopy. Communication between the operator and staff in the control room can be difficult, so often a two-way intercom or other communication devices are necessary. Complex interventional EP procedures such as AF ablations require the entire staff to be focused and “on the same page” as the physician. This can often be facilitated by having all of the EP equipment and staff in the procedure room; however, this will usually necessitate that all staff wear lead aprons. It is critical to work closely with a hospital’s biomedical engineering department when designing a new lab. Poorly-designed labs can have electrical “noise” issues. It is important that separate conduits are used for cables for the EP recording and mapping equipment and other necessary cables, such as power cords. Electrical outlets should be isolated and, in general, power strips should be avoided. Walls of the lab should have lead shielding to minimize radiation exposure to areas adjacent to the lab. If device implantations will be performed in the lab, operating room airflow standards should be met to reduce possibilities of device-related infections. EP Equipment and Technology The rapid evolution in the field of EP has largely been due to advances in technology. This is particularly true in the case of AF ablations. AF ablations have increasingly become anatomically-based procedures. Therefore, the advent of three-dimensional mapping and navigation systems and improved imaging techniques has facilitated the “explosion” in the number of AF procedures being performed worldwide. This section will discuss the technology commonly used in EP labs performing complex interventional EP procedures. There are several technologies that are absolute basic requirements for all interventional EP labs. These include fluoroscopy, a physiologic recording system, stimulator, and radiofrequency generator. The considerations for fluoroscopic imaging include biplane versus single-plane systems. Many electrophysiologists who perform AF ablations believe that biplane imaging can facilitate safe, successful procedures. Additionally, the fluoroscopy equipment should have the ability for digital storage of acquired cine images. The physiologic recording system is perhaps the most critical component in any EP lab. There are several systems from different manufacturers currently in use. Minimum requirements include at least a 64-channel capability; however, 128 or more channels are necessary for complex mapping technology. The recording system should also have the capability of at least two channels of hemodynamic monitoring. There are also several manufacturers of EP stimulators. Newer stimulators are computer-based, have touch-screen technology, and can interface with the recording system. However, most stimulators have similar capabilities, so physician preference is typically the most important factor in stimulator choice. Finally, there are several radiofrequency ablation generators currently available. These also generally have similar features; however, as manufacturers have not standardized catheter connections, specific generators are required for some ablation catheter technology. Some radiofrequency generators include a remote panel and/or foot-switch control, which allow their use from a separate control room. Defibrillation or cardioversion is frequently necessary in EP procedures. Therefore, an external defibrillator is required equipment for every EP lab. Current defibrillators in use deliver biphasic waveform shocks. Biphasic shocks have been shown to be more successful than monophasic waveform technology and allow lower energy amounts to be used. A backup defibrillator should be readily available for every EP room. It can be necessary to perform multiple synchronized cardioversions during AF ablations. The capability of internal cardioversion can reduce the energy required for cardioversion and minimize the risk of complications such as skin burns. There are special catheters and switch boxes available to perform internal cardioversion. Additionally, an external pacemaker should be available in every EP room, in the event that emergent temporary pacing is required. In addition to standard radiofrequency ablation technology, there are other ablation technologies in use in interventional EP labs. Many physicians performing AF ablations use irrigated-tip or cooled ablation technology. Irrigated-tip ablation systems include circulating room temperature saline to the tip of the ablation catheter to reduce heating of the catheter tip. This allows for more radiofrequency energy delivery and potentially faster and larger lesion formation. There are several manufacturers of irrigated-tip ablation technologies. The systems require proprietary catheters, fluid pumps, and radiofrequency generators. Another ablation technology in use is cryoablation. Cryoablation involves technology that cools the tip of the ablation catheter to very cold temperatures to “freeze” the arrhythmogenic tissue targeted by ablation. This technology can have advantages over radiofrequency ablation, especially in the pediatric population and in the ablation of certain accessory pathways. There are some limitations to cryoablation technology, though, including longer duration of lesions and higher recurrence rates when compared to radiofrequency. Most of the current techniques utilized in the ablation of AF are anatomically based. There are two three-dimensional mapping system technologies in common use for AF ablation. Each system has some advantages and limitations as compared to the other system. Three-dimensional mapping and navigation systems have historically allowed creation and visualization of a “virtual” left atrial anatomy that can be used to guide mapping and ablation. The latest generation of mapping system technology allows for the integration of previously attained CT or MRI images with the “virtual” left atrial chamber geometry. The subsequent mapping is performed on the “fused’ or “merged” anatomical image. The use of three-dimensional mapping systems can reduce the amount of fluoroscopy needed and reduce radiation exposure to patients and staff. Intracardiac echocardiography (ICE) is a very helpful tool to facilitate safe and successful interventional EP procedures. ICE allows the real-time visualization of cardiac structures. Transseptal punctures are a critical component to any AF ablation procedure. Many EP physicians consider ICE as the “standard of care” for guiding transseptal punctures. Other potential benefits of ICE include visualizing pulmonary veins, positioning of catheters, assessment of catheter-tissue contact, and the monitoring of lesion formation. In addition, ICE allows for prompt evaluation in the event of a suspected cardiac perforation and pericardial effusion. New technologies have been developed that have the potential to facilitate precise catheter steering and manipulation. Remote catheter navigation systems are under investigation that may result in reduced radiation exposure to the physician. These include systems with a magnetic guidance system, remote control of a steerable sheath, and a robotic catheter remote control system. These all provide the ability to remotely navigate a catheter from a control room. Future studies will show if these systems improve safety and outcomes of AF ablation. Conclusion EP, initially a diagnostic science, has become primarily an interventional subspecialty of cardiology. Newer technology has facilitated the mapping and ablation of complex arrhythmias. In some facilities, AF ablation is the most common ablation performed. New EP labs are being constructed at a rapid pace in hospitals with existing EP labs, as well as in hospitals that have not historically had EP labs. This article has reviewed the issues that are relevant to the design and construction of a new EP lab. In addition, it has listed the technology currently used to perform complex interventional EP procedures.