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Atrial fibrillation (AF) is the most common cardiac arrhythmia encountered in the United States. The prevalence of atrial fibrillation dramatically increases with advancing age. The increasing life expectancy of individuals in the United States, in conjunction with the increasing frequency of risk factors associated with atrial fibrillation such as hypertension and obesity, likely will lead to a continued increase in the number of individuals with atrial fibrillation. This activity reviews the pathophysiology of atrial fibrillation, its presentation, and available treatment options and highlights the role of the interprofessional team in the management of this arrhythmia. Objectives: Describe the anatomy of the left atrium and pulmonary veins. Explain the technique for performing pulmonary vein catheter ablation for atrial fibrillation. Review the complications of catheter pulmonary vein ablation of atrial fibrillation. Outline the importance of improving care coordination among the interprofessional team to enhance the delivery of care for patients undergoing cryoballoon pulmonary vein catheter ablation for atrial fibrillation. Access free multiple choice questions on this topic.

Atrial fibrillation (AF) is the most common cardiac arrhythmia encountered in the United States with about 3 million people reported being diagnosed with the disorder.[1] The prevalence of atrial fibrillation dramatically increases with advancing age. As our population has enjoyed greater longevity, along with the increasing presence of risk factors known associated with atrial fibrillation such as hypertension and obesity, the incidence and prevalence of AF is expected to continue to increase.[2] There is significant morbidity associated with the development and perpetuation of AF, including stroke, heart failure, cognitive impairment, renal failure, increased mortality and a negative impact to the quality of life.[3] As such, controlling the arrhythmia is often essential to patient quality of life and prognosis, but has been difficult to attain. Since Haussaiguarre et al. reported that AF most often began in the posterior left atrium surrounding the ostia of the pulmonary veins,[4] pulmonary vein electrical isolation via catheter ablation has been the cornerstone of nonpharmacological treatment of AF. Treatment of AF may be medical or surgical, depending on patient characteristics, duration of disease, symptoms, and patient preference. The two most frequently used energy sources used for ablation are electrocautery (known as radio-frequency), and cryoenergy,[5]; although other energy sources are being actively investigated for their efficacy and safety. Both methods have been employed during open-heart surgery with equal efficacy.[6] Catheter radiofrequency ablation, where electrocautery is delivered to the tip of a steerable wire, has been used to treat cardiac arrhythmias since the 1980s.[7] Catheter cryoablation, where liquid nitrogen is introduced to scar arrhythmic cardiac tissue, was more recently introduced to deliver less severe burns and thus a more controlled degree of injury.[7] It is most widely used in pediatrics due to the ability to reverse its effects if not applied for a long period due to its slow injury rate.[8]

Since Haussaiguarre et al. reported that AF most often began in the posterior left atrium surrounding the ostia of the pulmonary veins,[4] pulmonary vein electrical isolation via catheter ablation has been the cornerstone of nonpharmacological treatment of AF. Treatment of AF may be medical or surgical, depending on patient characteristics, duration of disease, symptoms, and patient preference. The two most frequently used energy sources used for ablation are electrocautery (known as radio-frequency), and cryoenergy,[5]; although other energy sources are being actively investigated for their efficacy and safety. Both methods have been employed during open-heart surgery with equal efficacy.[6] Catheter radiofrequency ablation, where electrocautery is delivered to the tip of a steerable wire, has been used to treat cardiac arrhythmias since the 1980s.[7] Catheter cryoablation, where liquid nitrogen is introduced to scar arrhythmic cardiac tissue, was more recently introduced to deliver less severe burns and thus a more controlled degree of injury.[7] It is most widely used in pediatrics due to the ability to reverse its effects if not applied for a long period due to its slow injury rate.[8] As radio-frequency energy has been the primary energy source used to electrically isolate all four pulmonary veins,[9] an extensive number of ablation lesions are needed to be delivered by wire to encircle the vein ostia. This posed a challenge of completely encircling the peri-ostial pulmonary veins to produce complete conduction block, leaving gaps in the ablation lines and less control in the degree of injury delivered, which could lead to injury to contiguous structures such as the esophagus.[10] In 2012 the FDA approved a multicenter examination of second-generation cryoballoon which is delivered through a catheter over a wire and can deliver a continuous encircling freeze lesion to the left atrial tissue surrounding the ostia of the pulmonary veins, thus being more consistent in ablation delivery and being less prone to gaps in the ablation field.[11] Cryoenergy's greater lesion control should also theoretically have less risk to injure deeper tissues and thus, safer.[12] A large multicenter trial in Europe showed both methods were equally effective in electrically isolating pulmonary veins and were equally effective in preventing recurrent atrial fibrillation.[13] This activity reviews the methodology of catheter cryoballoon ablation using a multicenter examination of second-generation cryoballoon to treat symptomatic AF and its expected outcomes and risks.

In a worldwide survey of 7000 patients who had undergone catheter ablation, complications included cardiac tamponade, thromboembolism causing cerebrovascular accidents, atrioesophageal fistula, pulmonary vein stenosis, and nerve injury-either phrenic or periesophageal vagal nerve.[23] The rate of death was .98 per 1000 patients. Less prevalent causes of death described in the study included myocardial infarction, torsades de pointes, septicemia, sudden respiratory arrest, extrapericardial pulmonary vein perforation, hemothorax, anaphylaxis, esophageal perforation from an intraoperative esophageal probe, and hematoma formation at the site of entry.[23] Ablation may be proarrhythmic itself and may lead to other tachyarrhythmias post-ablation. Exclusive to cryoballoon ablation and the most common complication is phrenic nerve palsy, due to its proximity to the right superior or inferior pulmonary veins.[24] This can be avoided by immediately stopping delivery of cryo energy, and immediately deflating the balloon by tapping the "stop cryo-ablate" button twice, at the first detection of loss of strength of diaphragmatic excursion by palpation or loss in amplitude of C-MAP on the surface ECG. The rate of pulmonary vein stenosis is less common in cryoablation.[25] Although cryoballoon ablation is considered less technically challenging compared to radiofrequency catheter ablation, more radiation is often required during cryoablation as cineangiography is often used to confirm complete PV ostial occlusion by the balloon, necessary for optimal freezing.[26]

An interprofessional approach to catheter ablation of the pulmonary vein is recommended. Effective communication among specialty trained nurses and clinicians will produce the best outcomes. [Level 5] AF is associated with enormous morbidity and mortality, costing billions of healthcare dollars each year. Catheter ablation of the pulmonary vein is one way to manage symptomatic AF. Primary care providers and nurse practitioners should consult with a cardiologist about the options for treatment of AF patients. Today, catheter ablation has shown good results but a significant number of patients do develop recurrences, and the procedure is not benign. In any case, catheter ablation remains the choice of symptomatic patients who do not respond to antiarrhythmic drugs.