[Change of left ventricular segment length by nitroglycerin measured by biplane coronary cineangiography in man (author's transl)].

Left ventricular size at different portions was evaluated following the administration of nitroglycerin to find whether there is any regional difference in the amount of shortening. In 6 patients with old myocardial infarction, biplane coronary cineangiograms were obtained before and after sublingual administration of nitroglycerin of 0.3 mg. The coordinates of the bifurcations of the left coronary artery at multiple sites were measured on the postero-anterior and lateral films and the spatial lengths (L) between any paired two points were calculated frame by frame covering one cardiac cycle. The maximum length (Lmax) was 63.2 +/- 3.1 (SE) mm before nitroglycerin as a whole and was 61.4 +/- 2.9 mm after nitroglycerin, showing no significant change. The minimum length (Lmin) also showed no significant change after nitroglycerin; from 56.1 +/- 2.9 to 54.9 +/- 2.6 mm. However, at the free wall, Lmax after nitroglycerin was reduced by 4.5 +/- 2.5%, and Lmax at the anterior septum was also reduced by 3.0 +/- 1.3%. Lmax at the base was unchanged after nitroglycerin. Lmin at the free wall and at the anterior septum were also reduced after nitroglycerin, 4.4 +/- 2.6 and 2.9 +/- 1.2%, respectively, and it was unchanged at the base. Since a reduction in the left ventricular size is effective in reducing myocardial oxygen demand and is effective in treating myocardial ischemia, it was suggested that nitroglycerin is more effective in relieving ischemia at the free wall and septum and less effective at the base.