Myocardial injury and pericarditis are uncommon complications of ablations , because heat from the procedure leads to necrosis of the local myocardial cells. In addition, extensive ablation and long-term ablation with high energy may increase the incidence of myocardial injury. Moreover, owing to a thin coronary sinus and surrounding atrium, complications such as myocardial injury, pericarditis, acute myocardial infarction (AMI), and vascular rupture are more likely to occur. In this report, the patient received multiple RF applications and large amounts of RF ablation energy, with ablation areas including the endocardial-coronary sinus. These procedures may have caused myocardial injury and pericarditis in this patient, as characterized by elevated serum levels of myocardial injury markers and an electrocardiogram showing pericarditis. Therefore, ablation should be performed very carefully. To avoid myocardial injury, pericarditis, coronary sinus perforation, and other complications caused by ablation, low RF ablation energy should be applied and the RF applications should be stopped immediately when patients experience chest pain or any other discomfort. If possible, detailed mapping should be performed to maximize the chances of successful ablation with a single burn in WPW.
The possibility of a coronary artery injury must be excluded if there is an elevation in the ST-segment of the electrocardiogram or serum troponin I level is significantly increased after the ablation procedure. Coronary artery injury is a rare complication with a reported incidence of 0.09% among all ablations. Its underlying mechanisms are not completely understood. Several hypotheses have been proposed by experts. One theory suggests that artery damage is inversely correlated with vessel size . Garabelli et al. have proposed that vessels less than 3 mm in diameter are more vulnerable to RF heat, owing to a lack of protection from the heat-sink effect. Certain procedural situations, such as linear ablation within the CS, may also increase this risk . Acute myocardial infarction has been attributed to the close proximity of RF lesions to the coronary artery, especially in the posteroseptal region and CS, as well as its branches. Stavrakis et al. have found an inverse correlation between the risk of coronary artery injury and the distance between the CS ablation site and coronary artery. This injury might be caused by CS muscle conduction . Therefore, care should be taken to avoid ablation within 5 mm of a major coronary vessel. Electrocardiograms, myocardial injury markers, and echocardiography should be routinely reexamined. When elevation in the ST-segment is sudden and the patient experiences persistent chest pain, coronary angiography is indicated to identify complications associated with coronary artery injury. AMI requires immediate percutaneous coronary intervention.
In this case, the patient underwent combined left atrial and coronary sinus ablation and showed higher serum levels of myocardial injury markers and elevated ST-segment in the electrocardiogram post-operation. Identifying whether an AMI occurred and determining a treatment strategy are essential. The electrocardiogram immediately after ablation was normal, and the patient was free of palpitation attacks. Sustained widespread concave ST-segment elevation, rather than convex ST-segment elevation and reciprocal ST-segment depression, was observed. The patient’s electrocardiogram three weeks later was normal without inverted T-waves. The inverted T-wave in AMI typically remains for several weeks to months. Furthermore, a post-operation echocardiogram revealed no organic heart disease but only mild pericardial effusion. Hence, an absence of inverted T-waves, symptoms of chest pain or chest distress, and regional ventricular wall motion abnormalities, as well as the presence of sustained widespread concave ST-segment and pericardial effusion suggested pericarditis rather than AMI. Considering of the absence of chest pain and the self-limiting nature of this kind of pericarditis, the patient was not treated with colchicine or adequate non-steroidal anti-inflammatory drugs (eg. aspirin 750–1000 mg every 8 h) for pericarditis after operation. This patient was scheduled for monitoring and asked to take aspirin 100 mg daily to prevent postoperative embolic events. Finally, she was discharged with no symptom and the reexamined electrocardiogram was normal after three weeks.
In summary, this is the first study to report on myocardial injury and pericarditis after combined left atrial and coronary sinus ablation in WPW syndrome. The findings underscore the need for careful ablation with low energy, especially when combined with CS ablation. It is essential to identify whether an AMI occurred and determining a treatment strategy after coronary sinus ablation. For postoperative patients, the changes in abnormal electrocardiogram and myocardial injury markers should be dynamically monitored together with symptoms and coronary artery angiography should be performed when necessary.