To analyze the clinical outcome and the factors influencing the recovery of left ventricular systolic function in children with tachycardia-induced cardiomyopathy (TIC).

we retrospectively analyzed 104 pediatric patients who were diagnosed with TIC from January 2009 to December 2021 in our center. The clinical characteristics, tachycardia mechanism, management, and prognosis data of the patients were collected. The positive endpoint event was defined as the restoration of left ventricular ejection fraction (LVEF), and a Cox proportional hazards model was established to evaluate the independent predictors for LVEF recovery.

A total of 104 patients (boys for 56.7%) were included. The median age at diagnosis of TIC was 10.0 (3.0, 82.0) months. The majority of cases were under 1 year of age (53.8%,56/104). The median LVEF was 39.5% (32.4%,44.8%), and the median Z-score for the left ventricular end-diastolic diameter (LVEDD) is 4.0 (2.4, 5.2). Focal atrial tachycardia (48.1%, 50/104) was the most common tachycardia. Ninety-six patients (92.3%, 96/104) were followed up for at least 1.0 month, with a median follow-up time of 23.0 (10.0, 53.0) months. At the last follow-up, 93 patients (89.4%, 93/104) had LVEF recovery of ≥ 55%, with a median recovery time of 1.0 (0.5,2.0) month. In the multivariate model, after adjustments of age, baseline LVEF, standardized baseline LVEDD and no heart failure treatment, age (HR=0.892 per year, 95%CI 0.844-0.943, P<0.001), baseline LVEF (HR=1.045 per 10%, 95%CI 1.013-1.079, P=0.006), standardized baseline LVEDD (HR=0.802, 95%CI 0.699-0.920, P = 0.002) were independent predictors of LVEF recovery.

The prognosis of TIC in children was good. Younger age, higher baseline LVEF and smaller baseline LVEDD were independent predictors of LVEF recovery.