In 1996, the American Heart Association and the North American Society of Pacing and Electrophysiology (NASPE, now the Heart Rhythm Society) published a scientific statement on Personal and Public Safety Issues Related to Arrhythmias That May Affect Consciousness: Implications for Regulation and Physician Recommendations.¹ In that document, recommendations were made that focused primarily on patients who had survived a potentially life-threatening ventricular tachyarrhythmia. For patients who had had an episode of ventricular fibrillation (VF) or sustained ventricular tachycardia (VT) and who subsequently underwent implantation of an ICD, the recommendation was made to restrict driving for a period of six months after implantation. Thereafter, patients could resume driving if no further episodes of VT or VF occurred. The 1996 recommendations were published just around the time the first results from the primary prevention trials were made public.

It is estimated that each year there are more than 900,000 implantable cardiac devices prescribed worldwide. There have also been an increasing number of MRI systems worldwide, with about 35 million magnetic imaging procedures performed yearly.^3,4 Because of the expanding clinical indications for both implantable devices and MRI, there are an ever-increasing number of patients who require both of these medical modalities. Due to the widespread application and powerful diagnostic capability of MRI, there are instances where denying a patient MRI evaluation may influence the quality of health care received. One study found that 17% of patients with pacemakers were denied MRI in the previous year. This may affect over 1 million patients worldwide.⁵ Studies to determine the safety of MRI in patients with devices are limited.

What is the size of your EP lab facility and number of staff members?

Case History This case involves a 65-year-old Caucasian woman with a one-year history of paroxysmal atrial fibrillation, who presented to our institution for curative ablation. Previously, she was rhythm-controlled with amiodarone and anticoagulated with warfarin. The patient had failed other anti-arrhythmic agents, declined long-term treatment with amiodarone, and thus had begun to have recurrent atrial fibrillation. Subsequently, she was referred to our institution for radiofrequency ablation of atrial fibrillation. A transesophageal echocardiogram was performed prior to ablation, which revealed a normal left atrium, right atrium, left ventricular size and ejection fraction, and normal pulmonary vein anatomy. A redundant atrial septum without shunting was appreciated. Normal configuration of the four pulmonary veins was exhibited by cardiac CT.

Dear readers, Just in time for the annual HRS meeting, we have prepared a big issue for you! Highlights from our May 2007 issue include: The question of whether or not an ICD patient should drive is an important quality of life issue. Therefore, an addendum to the 1996 Scientific Statement Personal and Public Safety Issues Related to Arrhythmias That May Affect Consciousness: Implications for Regulation and Physician Recommendations was recently released. Dr. Anne Curtis provides a summary on the updated guidelines. EP Lab Digest's first annual salary survey for EP lab professionals is also included in this issue, so please fill out the form at your soonest convenience! The salary survey form can be found both in this issue and on our Web site (www.eplabdigest.com). Once complete, the survey can be faxed or emailed back to us. Forms have already started coming in, so we look forward to publishing the results soon!

Approximately one year earlier, the patient had an episode of atypical chest discomfort that was ultimately diagnosed as a muscular strain. As part of his work-up, he underwent a cardiac stress test and echocardiogram, both of which were read as normal. His past medical history was otherwise unremarkable except for several episodes of syncope as a teenager and young adult, but these were always associated with vasovagal events such as seeing blood or standing in a hot church. At the time of his most recent presentation, he was on no medications and denied having any allergies. There was no family history of premature coronary disease, cardiac arrhythmias or sudden death, and his social history was also benign. On physical examination the patient was normotensive without orthostasis. The head and neck exam was unremarkable, and there was no carotid hypersensitivity. His cardiac exam was regular in rhythm with normal heart sounds and no murmur or gallop.

Historical Reports and Findings in the Animal Lab The first suggestion that paroxysmal atrial fibrillation (PAF) could be induced from parasympathetic or vagal ganglia came from Coumel in 1989.¹ In this work, two forms of PAF were proposed: one being an adrenergic form that occurred with exercise or stress, and the second form that was more likely to emerge during sleep, a vagal form. Subsequently, the autonomic nerve distribution of the heart was mapped, and these nerves were found to largely exist around the great vessels.² In a 1997 canine study, Chiou et al found the nerves converged into fat pads found around the SVC-aortic junction.

Describe the ENABLE trial. What is the purpose of the trial? The ENABLE (ENdoscopic ABlation using Light Energy) trial is a prospective, randomized, pivotal, multicenter, IDE clinical trial using an investigational endoscopically-guided laser balloon catheter (CardioFocus, Inc.) for the treatment of atrial fibrillation (AF). The study objective is to demonstrate the safety and effectiveness of this visually-guided endoscopic ablation system (EAS) in participants presenting with recurrent, paroxysmal, symptomatic AF by creating electrical isolation of the pulmonary veins (PVI). Currently there are no catheters approved in the United States for the ablation of AF. This trial is designed to assess the efficacy and safety of this new technology, as well as measure freedom of documented atrial fibrillation symptoms for 1 year post treatment. What are the start and end dates? When did enrollment begin?

The Texas Cardiac Arrhythmia Institute (TCAI) is helping to fulfill the need for an independent preparation course that reviews all of the exam's topics: Pacemaker Timing Cycles, Radiology, Technical Aspects of Pacing, Indications for Device Therapy, Rate Modulation/Sensor Technology, ECG Analysis and Troubleshooting, Bradycardia, Tachycardia, Pharmacology, and CRT. TCAI, which was founded in January 2006, offers courses to cardiac healthcare providers of all levels who wish to expand their clinical education and improve their skills and knowledge in EP and cardiology. The classes are designed under the supervision of the founding EPs. The educational programs have been approved by the appropriate agencies to offer CEUs for nurses and allied health professionals, as well as CMEs for physicians. TCAI mainly provides accelerated two- to three-day classes throughout the year. The syllabus handout itself is a great tool for self-study.

Arrhythmias can be bradycardias or tachycardias. Bradycardias are further divided into sinus bradycardias and heart block. Tachycardias can be supraventricular or ventricular. One should be very careful to describe the arrhythmia before giving a specific diagnosis. Too often one rushes to identify the P waves and QRS, and then leaps to a diagnosis. However, in many cases the diagnosis is not clear and indeed the arrhythmia cannot definitively be known by the surface electrocardiogram. Thus, it is far better to describe the arrhythmia and then given a differential diagnosis. Bradycardias Bradycardia can be caused by sinus bradycardia or heart block. In either, escape rhythms are seen. Junctional escape rhythms are at a heart rate of 40 - 50 beats per minute (bpm); ventricular escape rhythms are at a heart rate of 20 - 30 bpm. Sinus bradycardia is recognized by having a P wave prior to each QRS.