The patient experienced persistent, exacerbated tachycardia under continuous ritodrine infusion starting at 20 weeks of gestation and developed supraventricular tachycardia with an impaired left ventricular ejection fraction of 30% and an elevated N-terminal prohormone of brain natriuretic peptide (NT-proBNP) level of 2,122 pg/mL, at the time of transfer at 36 weeks of gestation. This evidence concerns the gene NPPB and Supraventricular tachycardia.