Improvement in respiratory function and exercise tolerance following video‐assisted thoracoscopic diaphragm plication for symptomatic iatrogenic persistent diaphragm paralysis after radiofrequency catheter ablation

Hemidiaphragm paralysis, a complication of catheter ablation for atrial fibrillation, can severely affect respiratory function and can lead to paradoxical breathing and dyspnea on exertion. A 75-year-old woman with iatrogenic diaphragm paralysis showed improved symptoms, respiratory function, and exercise tolerance after video-assisted thoracoscopic diaphragm plication. Radiofrequency catheter ablation is the primary treatment for drug-resistant symptomatic atrial fibrillation. Iatrogenic right diaphragm paralysis is a common complication of right pulmonary vein isolation and superior vena cava isolation.1 About half of cases of persistent diaphragm paralysis are asymptomatic and do not need surgery. However, the remainder experience symptoms, including dyspnea on exertion (DOE), shortness of breath, and cough.2 Surgical intervention for patients with severe symptomatic diaphragm paralysis includes diaphragm plication by video-assisted thoracoscopic surgery (VATS).3 However, electrophysiologists are often unaware of this surgical option. This report describes a patient with iatrogenic diaphragm paralysis who developed severe DOE with reduced respiratory function and exercise tolerance that improved significantly after diaphragm plication using VATS at 8 months after onset. A 75-year-old woman with drug-refractory symptomatic atrial fibrillation and atrial flutter was referred to our hospital. After obtaining the patient's consent, catheter ablation was performed under general anesthesia. Before the insertion of a supraglottic airway device, which secures a stable airway under general anesthesia, 40 mg of rocuronium was administered, followed by an intravenous dose of 10 mg every 30 min. Electroanatomical mapping was performed using the Ensite Navx system (Abbott, St. Paul, MN, USA). Bilateral pulmonary vein isolation was performed using 40 W with a Lesion Index of 4.5 as a guide. Subsequently, superior vena cava isolation was performed, with each application of energy at 30 W for 20 s when there was no capture of the phrenic nerve by ablation catheter pacing; otherwise, high-power (50 W) short-duration (5 s) ablation was performed. During phrenic nerve pacing, muscle relaxation was not antagonized in the interest of anesthesia safety (i.e., securing airway). Note that ablation catheter pacing might have been less sensitive because of muscle relaxation. Finally, cavotricuspid isthmus ablation was successfully performed (Figure 1A). The patient was discharged as scheduled on the day after ablation, but subsequently developed gradual worsening of DOE. Two weeks after ablation, a chest radiograph revealed an elevated right diaphragm, which continued for the next 6 months (Figure 1B–E; Video S1). Pulmonary function tests revealed severe restrictive and obstructive ventilatory impairment characterized by a vital capacity of 1.39 L (62% of the predicted reference value), a forced expiratory volume in 1 s of 0.91 L (57% of the predicted reference value), and a forced expiratory percentage in 1 s of 69%. The distance covered on the 6-min walk test was only 275 m, indicated a marked decrease in exercise tolerance (Table 1). At 8 months post-ablation, we proposed video-assisted thoracoscopic right diaphragm plication in view of the patient's progressively worsening dyspnea, leading to a profound negative impact on her quality of life. The patient agreed to undergo the surgery. A double-lumen tube was used to achieve single left lung ventilation under general anesthesia. The patient was placed in the left lateral decubitus position. Three incisions were made. The main working incision, through which suturing was performed, was 2.5 cm long and placed via the seventh intercostal space, extending posteriorly from the anterior axillary line. A 5-mm camera port was placed via the eighth intercostal space in the posterior axillary line. A 2.5-cm incision was made in the ninth intercostal space in the midaxillary line, through which forceps were inserted for suture bites and to grasp the diaphragm (Figure 2A). We performed plication using interrupted horizontal mattress sutures with polypropylene 2–0 and absorbable pledgets to prevent the device cutting through the tissue (Figure 2B,C). The procedure was carried out eight times to complete the diaphragm plication, ensuring that the diaphragm was no longer protruding. A chest tube was inserted, and the patient recovered consciousness from anesthesia, exhibiting effective spontaneous ventilation and meeting extubation criteria. After smooth extubation, a follow-up chest radiograph revealed significant improvement in the patient's condition (Figure 1E; Video S2). The patient was discharged 1 week after the surgery. One month after surgery, her pulmonary function tests showed significant improvement, with a vital capacity of 1.95 L (84% of the predicted reference value), a forced expiratory volume in 1 s of 1.43 L (83% of the predicted reference value), and a forced expiratory percentage in 1 s of 73% (Table 1). Her performance on the 6-min walk test had also improved, with an increase in distance covered to 450 m. Diaphragm paralysis resulting from phrenic nerve injury is a well-known complication of catheter ablation. The right phrenic nerve is at risk of damage during ablation because of its proximity to the right superior pulmonary vein and superior vena cava.2 Hemidiaphragm paralysis can have a significant impact on respiratory physiology, causing impaired pulmonary function and paradoxical breathing (Figure 3), which lead to DOE. Moreover, the patient is an elderly woman with obesity (154 cm and 68 kg, the BMI is 28.6 kg/m2), suggesting that her respiratory reserve was originally low. Iatrogenic diaphragm paralysis should be monitored for possible improvement for at least a year; however, 6 months may suffice in patients with severe symptoms.4 In this case, DOE progressively worsened with a clear decline in respiratory function and exercise tolerance, resulting in a significant decrease in quality of life, prompting referral to thoracic surgery for surgical consideration. Similar to our case, previous work reports a case where robot-assisted thoracoscopic diaphragm plication was used for iatrogenic diaphragm paralysis after catheter ablation.5 However, there is a critical difference between our case and theirs: They took a robot-assisted approach, while we performed video-assisted thoracoscopic surgery (VATS). Their robotic surgery has the drawback of lacking tactile feedback, potentially leading to an underestimation of tension. Indeed, their patient did not have significant improvement, potentially because of this drawback. In our video-assisted thoracoscopic surgery, the surgeon can directly feel the tension in the diaphragm. Video-assisted thoracoscopic diaphragm plication improves outcomes in patients with symptomatic hemidiaphragm paralysis.3 However, diaphragm plication is less commonly performed in adults than children, and non-specialist physicians may be unfamiliar with this treatment. Physicians conducting catheter ablation should be aware of this relatively less invasive surgical option for persistent symptomatic iatrogenic diaphragm paralysis. We thank Dr. Jungo Kasai for editing a draft of this manuscript. Authors declare no conflict of interests for this article. This research was conducted according to the principles of the Declaration of Helsinki. The patient provided written informed consent to publication of the details of her case. The authors confirm that all the data supporting the findings of this research are available within the article. Video S1. Video S2. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.