CHANGES IN PROGRAMMED ELECTRICAL-STIMULATION RESULTS, QT INTERVAL DURATION AND QT INTERVAL DISPERSION FOLLOWING PTCA IN PATIENTS WITH LEFT-VENTRICULAR HYPERTROPHY
J. Kaik et al., CHANGES IN PROGRAMMED ELECTRICAL-STIMULATION RESULTS, QT INTERVAL DURATION AND QT INTERVAL DISPERSION FOLLOWING PTCA IN PATIENTS WITH LEFT-VENTRICULAR HYPERTROPHY, HEARTWEB, 2(2), 1996, pp. 17-22
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.