title: Local conduction delay causes R-wave amplitude increase in patients with effort angina.
abstract: Eighty-seven unipolar electrocardiograms distributed over the entire thorax were simulataneously recorded before and after treadmill exercise in 43 patients. Exercise-induced R-wave amplitude change (delta R) and peak R time (time from the onset of QRS to the peak of R wave), were calculated for each lead. The maximal delta R of 87 leads was designated as the max delta R. After exercise, regional delay of peak R time (greater than or equal to 10 msec) on the chest was observed in 13 patients. These patients had significantly higher max delta R than those without such regional peak R time delay (0.71 +/- 0.31mV vs. 0.33 +/- 0.20mV, p less than 0.01). In each case, the site of peak R time delay was almost the same as the site of max delta R. There was no significant difference in the peak heart rate, rise of the systolic blood pressure (delta BPs) during exercise or extent of ischemic ST depression between patients with and without peak R time delay. We concluded that ventricular condition delay plays an important role in the increase of R-wave amplitude after exercise in patients with effort angina pectoris.
authors.affiliation: First Department of Internal Medicine, Yamagata University School of Medicine, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Ikeda
authors.forename: I
authors.initials: I
authors.lastname: Kubota
authors.forename: M
authors.initials: M
authors.lastname: Yamaki
authors.forename: H
authors.initials: H
authors.lastname: Igarashi
authors.forename: K
authors.initials: K
authors.lastname: Nakamura
authors.forename: K
authors.initials: K
authors.lastname: Tuiki
authors.forename: S
authors.initials: S
authors.lastname: Yasui
mesh_terms: D000328:Adult; D000368:Aged; D000787:Angina Pectoris / Q000175:diagnosis / Q000503:physiopathology*; D001830:Body Surface Area; D017023:Coronary Angiography; D004562:Electrocardiography / Q000379:methods; D005080:Exercise Test; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D005082:Physical Exertion