Prevention of pacing-induced silent myocardial ischaemia by nifedipine in coronary heart disease

• Published in: European heart journal Vol. 9 Suppl N; p. 151
• Main Authors: Pust, B, Sebenik, M, Obrez, I
• Format: Journal Article
• Language: English
• Published: England 01.12.1988
• Subjects: Administration, Sublingual; Adult; Aged; Angiography; Cardiac Pacing, Artificial; Coronary Disease - drug therapy; Humans; Male; Middle Aged; Myocardial Contraction - drug effects; Nifedipine - pharmacology
• ISSN: 0195-668X
• DOI: 10.1093/eurheartj/9.suppl_N.151

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).