This study was conducted to evaluate the predictive value of non invasive
predictors of ventricular tachycardia (VT) such as ejectionfraction (EF%),signal
averaged electrocardiogram (SAECG), heart rate variability (HRV)frequency of
premature ventricular contractions(PVCs) detected by Holier, and the new non
invasive predictor QT dispersion in patients with coronary arterydisease without
previous myocardial infarction in whom these predictors were not extensively
studied as in those withprevious myocardial infarction (M). This study included 72
patients with documented coronary artery disease by either coronary angiography
or stress test. 37 patients had a documented history of sustained ventricular
tachycardia. The rest ofpatients (35 patients ) had no suspicious history of
ventricular tachycardia or even any kind of arrhythmia andtheywere usedas a
control group. Data of SAECG, HRV, QTdispersion, andEF%were statistically
analyzed in each group and compared with the other group. Parameterswhich
showed highly significant difference were EF%, QRSd ofSAECG, pNNSO (HRV
parameter), and QT dispersion. Parameters, which showed less significant
difference, were presence oflatepotentials detectedby SAECG, andrMSSD (HRV
parameter). The rest ofparameters did not show any significant difference between
both groups. On evaluating the predictive value oftheparameters which showed
highly significant difference between both groups, EF% <50 was themost highly
sensitive (86.6%), andspecific (91.75%)parameterwith apositivepredictive value
of 86.04% and a negative predictive value of 93.6%. Combination ofEF%<50,
QRSd>120, pNN5070ms has amorepredictive value than
using each parameter alone. The sensitivity, specificity, positivepredictive value,
and negative predictive value ofsuch combinationwere 78.7%,98.8%, 97.3%, and
97.8% respectively. So, it can be concluded that, the non invasive predictors of
ventricular tachycardia which were used in patients with MI have also agood
predictive value in ischemicpatients withoutpreviousMI. Thepredictive value was
significantly increased by using combination of these predictors. QTdispersion
which is a new non invasivepredictor of VTcan be consideredas agoodpredictor
comparable with other predictors and even better than others |
