REDUCTION IN QT INTERVAL DISPERSION BY SUCCESSFUL CORONARY ANGIOPLASTY IN UNSTABLE ANGINA OR MYOCARDIAL INFACTION

<正> Increases of QTc interval diapersion has been reported to be amarker for ischemia.The effects of coronary artery revascularizationon QTc dispersion have not been previously reported.We studiedOTcd in 34 patients with a mean age of 55 years(range 31-72)withcoronary artery disease who underwent successful,uncomplicatedcoronary angioplasty(PTCA).We analysed 12-lead ECGs recordedbefore,1 day and a week after the PTCA.QT intervals were mea-sured by an observer who was blinded to the time the ECG wasrecorded,and to all other clinical information.QT intervals were cor-rected using Bazett's formula.QTc interval dispersion was calculatedas the difference between the maximum and minimum of the 12-lead EKG QTc interval.The QTc dispersion in a day(35±13)and(34±13)a week after PTCA was significant less reductive than theQTc dispersion(64±16),before PTCA(P<0.05).Successful reves-cularization by PTCA results in a significant reduction in QTc inter-val dispersion which persists over time.It may be a mechanism ofbenefit of PTCA therapy.Whether this measurement would predictrestenosis in such patients requires further study.