Prolongation of QT Interval as a Predictor of No-Reflow Induced by Rotational Atherectomy

Abstract

Although coronary rotational atherectomy (RA) is widely applied to clinical cases, the incidence of coronary no-reflow associated with it is higher than in percutaneous transluminal coronary angioplasty (PTCA) and stenting. This study was undertaken to predict no-reflow by using conventional electrocardiograms (ECGs). A total of 105 patients who underwent RA (group 1) and 40 who underwent PTCA (group 2) were studied. Eight patients of group 1, all of whom had long calcified coronary lesions, were complicated with no-reflow following RA. Standard 12- lead ECGs were recorded before and throughout the interventional procedures. Maximum and minimum QT intervals and QT dispersion were measured and corrected by heart rate. Corrected and uncorrected QT intervals and QT dispersion were significantly prolonged by RA in group 1 patients without no-reflow: maximum QTc, 428 ±28 ms → 485 ±53 ms, p<0.001. The increases in QT intervals were more remarkable in group 1 patients with no-reflow: maximum QTc, 434 ±15 ms → 552 ±39 ms, p<0.001. Of the 33 patients with maximum QTc ≥500 ms, 8 were complicated with no-reflow. No patients with maximum QTc < 500 ms had no-reflow. There was no significant increase in QT intervals in group 2. Adsorption of calcium ions from the myocardium by pulverized calcified atheromatous debris when these pass through coronary capillaries, resulting in transient myocardial hypocalcemia, was considered as a possible mechanism of QT prolongation. Because QT prolongation appears during the initial RA trial, prolonged QT intervals could be a predictor of no-reflow. It is recommended to avoid repetitive RA if marked QT prolongation is observed at the initial RA trial.