Risk factors for development of ventricular tachycardia in patients with ventricular premature contraction with a structurally normal heart

Background: We examined risk factors for development of ventricular tachycardia (VT) in pediatric patients with ventricular premature contractions (VPCs) and a structurally normal heart. Methods: The subjects were 81 844 first graders and 88 244 seventh graders of Kagoshima City School-based cardiovascular screening (SCV-screening) between 2001 and 2015. We retrospectively reviewed the clinical data of students who were diagnosed as having VPC. Results: Ventricular premature contractions were observed in 134 first graders (0.16%) and 270 seventh graders (0.31%). On the screening electrocardiograms (ECGs), 43 patients (11%) showed bi-/trigemini, three patients (0.7%) showed a couplet, and one patient showed VT. We obtained 166 patients' follow-up information and evaluated 59 patients (36%) as improved, 97 patients (58%) as no change, and 10 patients (6%) as worsened (couplets, five; triplets, two; VT, three). We assumed that these worsened patients have risk factors for development of VT. Comparing the findings of SCV-screening ECGs of risk patients with the others, a significant difference was observed only in the number of VPCs (per 10 seconds) (mean +/- SD; 4.3 +/- 2.6 vs 1.8 +/- 1.4, P < .0001). A logistic regression analysis revealed that the number of VPCs was significant (P < .001, odds ratio; 2.01, 95% confidence intervals; 1.46-2.93). Receiver operating characteristics analysis showed an adequate cut-off number of three VPCs for the risk, the sensitivity was 89% and the specificity was 77%. Conclusions: Of the patients with VPC and a structurally normal heart, a few patients developed VT. Careful observation is important in patients who had three or more VPCs on SCV-screening ECG.