Every procedure laboratory requires a basic setup common to all diagnostic and therapeutic electrophysiological procedures. The central piece of equipment in these procedure labs is the fluoroscope. This technology has evolved greatly over the past decade. Image quality is better and fluoroscopic dose exposure to the patient and the operator has been reduced. New systems employ CCD image detecter technology to achieve this end. The fluoroscopic exposure to the patient and the lab personnel follows the ALARA standard—as low as reasonably acceptable. The ALARA standard implies that there is no minimum safe dose for exposure to ionizing radiation. Therefore, any approach and technique that will minimize the fluoroscopic usage will benefit everyone. The use of pulsed fluoroscopy is highly recommended (1). Experienced operators frequently find that a pulsed frequency of seven frames per second allows adequate temporal resolution for safe fluoroscopically guided catheter manipulation.

Qualified radiation safety personnel should monitor all fluoroscopy laboratories regularly. All personnel should wear radiation safety badges at all times so that their exposure can be monitored. In order to minimize fluoroscopic exposure to personnel working in the room, particularly for the operator working in the field, appropriate shielding around the patient should be employed. This includes a portable lead shield to be placed between the image intensifier and the operator. Close positioning of a curved shield to the patient’s body will minimize radiation scatter. All procedure
tables should have a skirt below the table to prevent scatter from being transmitted at that level, and addition of a groin shield may further reduce operator and patient exposure (2). Additional fixed or portable shielding can be configured to block as much direct radiation transmission to the staff as possible. In order to minimize patient exposure to fluoroscopy, the use of pulsed fluoroscopy, and working conscientiously to minimize fluoroscopy time are the best approaches. If the fluoroscopy exposure is more prolonged, changing angles of the C-arm will distribute the radiation dose more equally over the skin. Prolonged radiation exposure to the skin can lead to substantial toxic effects including large, nonhealing skin ulceration (3,4). The image intensifier should be positioned as close as possible to the patient to minimize scatter, and the table should be as far from the radiation source as is feasible. The most promising advance to minimize radiation exposure is the wide adoption of non-fluoroscopic catheter navigation systems as described below.

Most laboratories presently employ either the single plane or biplane C-arm fluoroscopy systems. If catheter manipulation is going to be predominantly guided by fluoroscopy, then a biplane fluoroscopy system will save valuable time repositioning the C-arm. Early studies of atrial fibrillation guided solely by fluoroscopy reported prolonged fluoroscopy times (exceeding 120 minutes) and high radiation exposure with average peak skin doses of radiation of 1 Gy, and in selected labs exceeding 8 Gy (5,6). However, the ease of 3-D navigation systems (7,8) (see Chapter 7) and routine use of intracardiac echocardiography (9,10) (see Chapter 5) have rendered biplane fluoroscopy superfluous in many laboratories. In these cases, most catheter manipulation is done in a computer rendering of the heart in one or two planes, and with real-time imaging of the catheter position in the heart by ICE, fluoroscopy is only used infrequently to confirm the position of the catheter.

It is recommended that any laboratory used for catheter ablation of atrial fibrillation have cine angiography capabilities with digital or other storage. Pulmonary vein angiography is often employed to identify the junction between the pulmonary vein and the left atrial body, and to measure the caliber of this vessel (11,12). It has been observed that the risk of significant pulmonary vein stenosis increases as ablation is applied deeper into the vein, and conversely, that risk is much lower if extraostial ablation or wide-area circumferential ablation strategies are employed (13). The technique routinely employed for pulmonary vein angiography is subselective engagement of each vein with hand injection of 5 to 10 cc of contrast material. An alternative approach uses a single 10-cc injection of contrast medium into the left atrial body after injection of a dose of adenosine sufficient to cause transient sinus arrest and asystole. With the heart in standstill, the single-dye injection effectively opacifies all pulmonary veins. Vein angiography may become even more important as new balloon technologies are utilized more for pulmonary vein isolation procedures (see below). In cases where successful ablation depends on circumferential balloon-tissue contact, complete vein occlusion by the ablation balloon can best be demonstrated by dye injection through a central lumen of the ablation catheter into the distal pulmonary vein segment. If the dye does not wash out of the vein, then one may assume that occlusive contact has been achieved.

All laboratories performing diagnostic electrophysiology (EP) testing, catheter ablation, and especially atrial fibrillation catheter ablation should have a multichannel
computerized EP lab system. These systems should be capable of displaying real-time 12-lead electrocardiograms and intracardiac electrograms from no less than 32 channels (64 channels preferred). The standard setup for intracardiac monitoring varies among laboratories. In most cases, a referenced catheter should be positioned in a stable position, usually the coronary sinus. Electrograms from 8 or 10 poles are displayed as 4 or 5 bipolar recordings. Some operators elect to use a 20-pole halo catheter position in the right atrium. Most operators use one or two 10- to 16-pole circular electrode catheters positioned in the pulmonary vein for assessment of presence or absence of pulmonary vein potentials (14,15). Finally, electrograms from a roving mapping/ablation catheter should be displayed.

Other advanced mapping and imaging equipment is routinely employed during atrial fibrillation ablation and will be discussed in detail in subsequent chapters. These technologies include intracardiac echocardiography and 3-D electroanatomical mapping systems. These systems may be used to visually guide catheter manipulation by the operator, or may be coupled with advanced robotic navigation systems. It is necessary that the EP system tracings be displayed real time on a monitor in the monitor cluster in front of the operator. Other displays in the monitor cluster should include the real-time fluoroscopy, last image hold or cine fluoroscopy loop, 3-D mapping system computerized display, and intracardiac echo display. An appropriate generator or proprietary power supply to the ablation technology being employed (cryotherapy, laser, or high-intensity focus ultrasound) should be available with a backup generator in the area should technical difficulties be encountered.

Presently, atrial fibrillation ablation is a time- and labor-intensive procedure. It is necessary that the patient rest quietly on the procedure table for 3 to 6 hours. Often, the cath procedure is preceded by transesophageal echocardiography, thus further prolonging total procedure duration. In order to maintain patient comfort and compliance, procedural sedation and/or anesthesia is required. The approach selected is dependent on the experience and preferences of the physician and nursing staff, and on the characteristics of the patient. Patients with obesity, sleep apnea, or other history of airway obstruction, those with hemodynamic instability, and those with low pain tolerance and/or dysphoric responses to narcotics are typically better treated with general anesthesia. General anesthesia provides optimal airway management, pain control, and prevents patient movement during catheter manipulation for mapping and ablation. The disadvantages of general anesthesia are minimal but include the small risk of trauma due to intubation, and the need for anesthesia staffing throughout the long case.

An alternative approach to general anesthesia during atrial fibrillation ablation is moderate procedural sedation. Patients are typically sedated with combinations of short-acting narcotics, benzodiazepines, and propofol. Importantly, patients should be sedated to the point of sleeping but remain easily arousable. This assures adequate minute ventilation and proper airway protection. If patients cannot be easily awakened, then the level of anesthesia is deep sedation. During deep sedation, patients are at risk for hypoventilation and aspiration. Nurses and physicians administering sedation during atrial fibrillation procedures should be trained in procedural sedation techniques, and patient monitoring should include noninvasive or arterial blood pressure, heart rate, and oxygen saturation (16). Guidelines for assessing levels of
anesthesia and training requirements for administration of intravenous sedation during procedures have been developed by the American Society of Anesthesiologists and may be found on their web site link to this guideline (17).

Whether the patient is managed with general anesthesia or deep procedural sedation, the patient needs to be closely monitored. At a minimum, continuous ECG monitoring, noninvasive blood pressure monitoring, and continuous pulse oximetry is required. The patient should be connected to the adhesive defibrillation electrodes so that they can be promptly resuscitated should catheter manipulation or program electrical simulation initiate a poorly perfusing arrhythmia. Additional equipment required will include IV setups, infusion pumps, and pressurized saline infusion setups for introducers placed on the systemic circulation. Because atrial fibrillation ablation is performed in the left atrium and heparin anticoagulation is required throughout the case, an activated clotting time (ACT) machine is required to adjust anticoagulation. It is necessary that this machine is appropriately maintained and calibrated.

Finally, it is important that the lab be equipped with a complete complement of resuscitation equipment including a bag and a mask for ventilation, crash cart for emergency intubation, and a full selection of medications used during resuscitation. Because pericardial tamponade is a well-recognized complication of catheter atrial fibrillation ablation procedures, a pericardiocentesis setup should be immediately available at all times.