title: Prevention of pacing-induced silent myocardial ischaemia by nifedipine in coronary heart disease.
abstract: In 11 patients with angiographically documented significant coronary heart disease silent (asymptomatic) segmental myocardial ischaemia was induced by rapid atrial pacing using the sub-threshold rate (10 impulses min-1 less than angina-threshold rate). The effect of pacing-induced silent myocardial ischaemia on the left ventricular contraction was studied from three consecutive quantitative cineventriculographies--performed in control conditions (I) and during sub-threshold pacing before (II) and after (III) 20 mg nifedipine sublingually. On this basis, left ventricular mean relative hemiaxis shortening (X delta r%) for anterior, inferior and apical segments as well as ventricular volumes and ejection fraction using an area-length method were determined for every patient. Sub-threshold atrial pacing significantly (P less than 0.0005) reduced X delta r% of non-infarcted post-stenotic myocardial segments (36 +/- 10%----23 +/- 10%; N = 14) having no significant effect on the contraction of normal and infarcted segments. As a consequence, left ventricular ejection fraction (72 +/- 10%----64 +/- 14%; P less than 0.005) and end-systolic volume (33 +/- 16 ml----43 +/- 20 ml; P less than 0.005) deteriorated too. After 20 mg nifedipine sublingually in post-stenotic non-infarcted segments characterized by pacing-induced silent ischaemia, normalization of X delta r% (23 +/- 10%----42 +/- 11%; P less than 0.0005) was observed together with significant improvement of ejection fraction (64 +/- 14%----75 +/- 10%; P less than 0.005) and with reduction of the aortic end-diastolic pressure (P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department for Cardiovascular Diseases, University Clinical Center VII, Ljubljana, Yugoslavia.
authors.forename: B
authors.initials: B
authors.lastname: Pust
authors.forename: M
authors.initials: M
authors.lastname: Sebenik
authors.forename: I
authors.initials: I
authors.lastname: Obrez
mesh_terms: D000286:Administration, Sublingual; D000328:Adult; D000368:Aged; D000792:Angiography; D002304:Cardiac Pacing, Artificial; D003327:Coronary Disease / Q000188:drug therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction / Q000187:drug effects; D009543:Nifedipine / Q000494:pharmacology*
chemical_list: D009543:Nifedipine