CHANGES IN PROGRAMMED ELECTRICAL-STIMULATION RESULTS, QT INTERVAL DURATION AND QT INTERVAL DISPERSION FOLLOWING PTCA IN PATIENTS WITH LEFT-VENTRICULAR HYPERTROPHY

The aim of the study was to evaluate the effect of successful PTCA on enhanced myocardial electrical instability, assessed by programmed ven tricular stimulation (PES) and QT/QTc interval dispersion (QTD/QTcD) d etermination in 27 CAD patients (pts) with left ventricular hypertroph y (LVH). According to PES data before PTCA the pts were divided into 2 groups: Group 1-21 pts with sustained monomorphic VT, Group 2 - 6 pts with sustained polymorphic VT/VF. Although angioplasty caused signifi cant decrease in QTD (from 121+-19 to 89+-19ms and 118+-21 to 71+-17 m s, respectively) and QTcD (from 123+-16 to 92+-18ms and 126+-19 to 88-19 ms, respectively) in both groups, its effect on the inducibility o f the arrhythmia was different: PTCA abolished the induction of arrhyt hmia in 3 pts (14.3%) in Group 1 and in 5 pts (83.3%) in Group 2. Thus , although PTCA reduced ventricular repolarization inhomogeneity asses sed by QTD and QTcD determination, the effect of coronary angioplasty on the induction of monomorphic VT and polymorphic VT/VF differs signi ficantly, possibly because of different electrophysiologic mechanisms of these two types of arrhythmias. Myocardial revascularization has be en shown to improve the prognosis for certain subgroups of CAD patient s, but the data concerning the effect of CABG and PTCA on the level of myocardial electrical instability assessed by different methods of in vestigation are relatively limited [1] [2] [3]. The aim of the study w as to evaluate the effect of successful PTCA on the enhanced myocardia l electrical instability in CAD patients with electrocardiographically and echocardiographically determined left ventricular hypertrophy -th e patients a priori predisposed to the risk of sudden death. The concu rrent high-grade electrical instability in these patients was expresse d by inducibility of sustained VT/VF during PES and increased QT and Q Tc interval duration.