This double-blind randomized placebo (PL) controlled study was undertaken to evaluate, by 2D echo transesophageal atrial pacing (TAP), the effects of acute iv administration of a new compound propionyl-L-carnitine (PLC) on atrial pacing (AP) induced left ventricular wall motion abnormalities. Twelve male patients with coronary artery disease and normal regional motion at rest, after a preliminary 2D echo-TAP, on the eight and thirteenth day of trial were subjected to 2D echo-TAP 30 min after iv administration of 15 mg/Kg PLC or PL. For analysis, the left ventricle was divided into 11 segments. A wall motion score (WMS), evaluated at 130 b/min and at 150 b/min, was derived by adding together the scores assigned to each segment. Wall motion was graded +2 (normokinetic), +1 (hypokinetic), 0 (akinetic), -1 (dyskinetic). Left ventricular ejection fraction (EF) was evaluated at rest and at 150 b/min. Statistical analysis of the results was performed using a 2-way analysis of variance. The WMS at 130 b/min improved significantly after PLC vs PL from 18.66 +/- 2.46 to 19.50 +/- 2.77 (p less than 0.02). The WMS at 150 b/min improved significantly after PLC vs PL from 16.00 +/- 2.95 to 16.91 +/- 3.47 (p less than 0.01). The EF at rest was not significantly unchanged after PLC. The EF at 150 b/min was significantly different after PLC vs PL, from 53.6 +/- 7.36 to 55.6 +/- 6.45 (p less than 0.05). The blood pressure and the double product at rest and at 150 b/min were not unchanged after PLC.(ABSTRACT TRUNCATED AT 250 WORDS)