QTC TENDENCY IN PACEMAKER DEPENDENT PATIENTS - PROGNOSTIC MEANING OF LONG QTC DURING 5 YEAR FOLLOW UP.

Prolongation of ventricular repolarization, which is represented by QTc prolongation on the standard ECG can be considered as increased risk for fatal arrhythmia. However, in pacemaker dependency (with ventricular pacing from the right apex) Ventricular Pacemaker causes abnormal steps of ventricular activation and therefore widens QRS complex and alters ventricular repolarization. It is still questionable whether QTc prolongation in right ventricular-paced patients is associated with increased risk of fatal arrhythmia or other cardiac complications. The other important question is whether the pacemaker dependent patient with long QTc interval may safely receive medications with known potential to prolong ventricular repolarization. The aim of the study was to determine whether QTc prolongation in VP (ventricular pacemaker) patients is associated with increased risk of fatal arrhythmia or other cardiac complications and whether these patients can safely receive medications with known potential to prolong ventricular repolarization. The study is based on retrospective analysis of the QTc interval prior and after pacemaker insertion; dynamic changes of QTc interval and possible influence of the medications, with known potential to prolong ventricular repolarization. Study population consisted 76 patients with narrow native QRS complexes and QTcF/QTcB <500 ms for both male and female patients. QTc prolongation in VP patients most likely does not represent true repolarization abnormalities and is not associated with risk of fatal arrhythmia. While analysis of group receiving medications with known potency of QTc increase we found no additional tendency of QTc increase. Based on our data receiving the medications with known potency of QTc prolongation in VP patients should be considered as safe approach. Long-term follow up data (5 years) assessed retrospectively shows that in patients with widened QRS after VP are at increased risk of development of HF and HF decompensation.