Study population
A 12-year-old girl weighing 46 kg and 165 cm in height (with a body surface area of 1.45 m2) presented with almost incessant, drug-refractory AT was referred for radiofrequency catheter ablation. She had a 5-month history of palpitations, and the electrocardiogram (ECG) showed persistent atrial tachycardia with variable (3-1:1) conduction, and a maximum heart rate of 150 beats/min (Figure 1).
The echocardiogram revealed enlarged left atrium diameter (LAD, 37 mm; normal range < 35 mm). The left ventricular end-diastolic and end-systolic diameters (LVEDD and LVESD) were 48 (normal range < 48 mm) and 30 mm, respectively, with a normal left ventricular ejection fraction (LVEF) of 67% (Table 1). The markers of myocardial injury were normal, and no inflammatory edema of myocardial tissue was found by echocardiography. The ECG was repeated, and the results showed the AT was in the range of 140-180 beats/minute without dynamic ST change. The atrial tachycardia lasted for more than 2 days with elevated NT-proBNP (2586 pg/ml, normal range < 285 pg/ml), elevated GPT (109 U/L, normal range < 75 U/L), and elevated GOT (43 U/L, normal range < 38 U/L) level.
After ruling out reversibility and other causes, the patient was admitted to the hospital for electrophysiology examination and ablation. Transesophageal echocardiography (TEE) was performed before ablation to verify the absence of a left atrial thrombus and guide LAA resection. Patients had been treated with anticoagulants before ablation.