gms | German Medical Science

Polymorphic ventricular tachycardia (PVT) is a rare malignant specimen of cardiac arrhythmia, associated with syncope, high risk of ventricular fibrillation and sudden cardiac death (SCD). This primary ventricular tachyarrhythmia mainly occurs in childhood therefore the most of its major characteristics and long-term clinical consequences are known form the pediatric practice. Elaboration of the risk stratification based on evaluation of clinical data and prognosis in children with PVT is the aim of our study.

Patients and Methods: A total of 25 children aged 13.2 ±2.9 years with PVT were studied and followed up. Clinical symptoms, pedigree, ECG, Holter, Echo, EPhy-study (5 children) and monitoring of individual risk factors were performed. The results were compared with similar data of 102 children aged 13.7 ±3.5 years with congenital Long QT syndrome (LQTS). Risk scores were defined for every variable, and each component was calculated as the score times prevalence of this variable in the group.

Results and conclusions: 88% of pts with PVT and 46% of pts with LQTS had syncope. Aborted SCD were reported in 36% of cases with PVT and 14.9% pts with LQTS. Risk factors were devoted into changeable (syncope, bradycardia, T-alternans, VPB, etc) and unchangeable (family history, sex). Children with PVT differ from LQTS pts in relationship between age and occurrence of 1st syncope (U-shaped in pts with PVT). Supraventricular tachycardia plays a role of trigger for PVT in 60% of pts. Male sex has not so strong modulating effects on the clinical manifestation and on the probability of death in PVT pts. Risk of SCD among the syncopal PVT pts is associated with concentration of changeable risk factors and with unchangeable risk factors in LQTS pts (1st syncope before the age of 6, male sex, sudden death in family below the age of 40, LQT3 or double dose of mutation). On the base of risk stratification ICD were implanted in 5 pts with PVT.