Effect of rapid atrial pacing on left ventricular ejection fraction in patients without organic heart disease

• Published in: Zeitschrift für Kardiologie Vol. 76; no. 4; p. 223
• Main Authors: Voelker, W, Mauser, M, Kimmig, A, Hoffmeister, H M, Overkamp, D, Karsch, K R
• Format: Journal Article
• Language: German
• Published: Germany 01.04.1987
• Subjects: Adult; Blood Pressure - drug effects; Cardiac Output - drug effects; Cardiac Pacing, Artificial; Coronary Disease - diagnosis; Female; Heart Rate - drug effects; Humans; Male; Middle Aged; Myocardial Contraction - drug effects; Nifedipine - administration & dosage; Stroke Volume - drug effects
• ISSN: 0300-5860; 1435-1285

Pacing-induced decrease of left ventricular ejection fraction (LVEF) in patients with coronary artery disease has been proposed as a sign of myocardial ischemia, whereas a slight increase or no change is speculated to be the normal response to rapid atrial pacing. The studies of the pacing-induced effects in normals, however, are of limited value, because of either inhomogeneous patient population or different, mainly non-invasive, methods for determination of LVEF. It was therefore the aim of the present study to assess the pacing-induced changes of left ventricular ejection fraction in a homogeneous group of patients. In 10 patients (mean age: 48 +/- 2 years) with normal coronary arteriograms and normal LV-function at rest, rapid atrial pacing was performed stepwise to a maximal pacing rate of 150 beats per minute. In all patients left ventricular end-diastolic pressure LVEDP and time constant of relaxation period tau decreased, while the parameter of contractility Max Dp/dt increased due to increase in heart rate. Furthermore, there was no limited coronary reserve or myocardial lactate production during atrial stimulation as a sign of pacing-induced ischemia. In all patients biplane ventriculography was performed at rest and during maximal stimulation. While end-diastolic volume index EDVI decreased in every patient (71 +/- 5---42 +/- 4 ml/m2, p less than 0.005) and systolic volume index did not change (17 +/- 2---14 +/- 2 ml/m2, N.S.), there was a significant decrease of ejection fraction from 75 +/- 2 to 66 +/- 3% (p less than 0.005). Basal heart rate, age, sex or basal ejection fraction did not influence the response of ejection fraction to rapid atrial pacing. Even after drug-induce afterload reduction there was a significant pacing induced decrease of ejection fraction.