Angioplasty decreases prolonged QT dispersion in patients with angina pectoris but not in patients with prior myocardial infarction

Background and hypothesis: Prolonged QT dispersion (QTd) is shortened by su ccessful percutaneous transluminal coronary angioplasty (PTCA) in patients with ischemic heart disease. Particularly QTd plays an important role in th e prognostication in patients with prior myocardial infarction (MI). Howeve r, whether the effect of PTCA on QTd differs in patients with and without p rior MI is not clear, and this study sought to clarify this question. Methods: In 41 consecutive patients with ischemic heart disease, we measure d QTd from a routine 12-lead electrocardiogram taken at 72 h before and aft er successful PTCA. Patients were divided into two groups based on the pres ence or absence of prior MI: Group 1 consisted of 24 patients with angina ( 61 +/- 11 years old) without prior MI and Group 2 was comprised of 17 patie nts (69 +/- 10 years old) with prior hll. QTd was calculated as the differe nce between the maximum and minimum QT and QT corrected for heart rate (QTc ), using Bazett's formula for calculating QTcd. All measurements were obtai ned manually and blindly. Results: In Group 1, 15 of 24 patients (63%) demonstrated multivessel disea se and 16 of 24 (67%) patients had high QTd > 60 ms. Percutaneous translumi nal coronary angioplasty decreased QTd and QTcd in Group 1 (QTd, from 83 +/ - 35 to 57 +/- 19 ms, p < 0.05; QTcd, from 89 +/- 37 to 63 +/- 33 ms, p < 0 .05), whereas no changes were observed in Group 2 (QTd, from 73 +/- 25 to 6 9 +/- 22 ms, NS; QTcd, from 80 +/- 30 to 79 +/- 28 ms, NS). QTd is more sen sitive to decrease by successful PTCA in patients with angina than in patie nts with prior MI. Conclusions: The effect of successful PTCA on inhomogeneity of ventricular repolarization reflected by QTd in patients with prior hn is different from that in patients without prior MI.