title: Effect of pericardium on regional myocardial systolic function in acute ischemia.
abstract: To know whether or not the pericardium affects regional myocardial systolic function in acute ischemia, we measured ischemic and non-ischemic segment lengths of the left ventricle using ultrasonic crystals in 10 open-chest dogs with the pericardium preserved. When the left ventricular pressure and segment lengths were stable after left circumflex coronary occlusion, we opened the pericardium widely. After coronary occlusion, end-diastolic length (EDL) in ischemic and non-ischemic segments increased, and the ischemic segment showed paradoxical systolic expansion while the non-ischemic segment increased its active shortening. After pericardiectomy, heart rate, left ventricular systolic pressure, and peak positive and negative dP/dt did not change. EDL in ischemic and non-ischemic segments further increased from 12.02 +/- 0.18 to 12.50 +/- 0.16 mm (mean +/- S.E., p less than 0.01) and from 11.12 +/- 0.20 to 11.45 +/- 0.18 mm (p less than 0.05), respectively, despite the concomitant fall in left ventricular end-diastolic pressure (LVEDP) from 12.4 +/- 0.6 to 10.6 +/- 0.8 mmHg (p less than 0.01). End-systolic length in ischemic and non-ischemic segments also increased from 12.37 +/- 0.25 to 12.70 +/- 0.20 mm (p less than 0.05) and from 8.50 +/- 0.13 to 8.74 +/- 0.13 mm (p less than 0.01), respectively, although the left ventricular end-systolic pressure did not change. Maximum expanded systolic length of the ischemic segment also increased from 12.99 +/- 0.20 to 13.42 +/- 0.16 mm (p less than 0.01). These results indicate that, in acute ischemia, the pericardium inhibits paradoxical systolic expansion of the ischemic region and increase in end-systolic length of non-ischemic segment. Thus, it is concluded that the pericardium modifies the regional myocardial systolic function in acute ischemia, perhaps through the mechanical restraint of the pericardium.
authors.affiliation: First Department of Internal Medicine, Tohoku University School of Medicine, Sendai.
authors.forename: K
authors.initials: K
authors.lastname: Shirato
authors.forename: K
authors.initials: K
authors.lastname: Ishikawa
authors.forename: M
authors.initials: M
authors.lastname: Kanazawa
authors.forename: T
authors.initials: T
authors.lastname: Nakajima
authors.forename: K
authors.initials: K
authors.lastname: Munakata
authors.forename: M
authors.initials: M
authors.lastname: Sakuma
authors.forename: T
authors.initials: T
authors.lastname: Haneda
authors.forename: T
authors.initials: T
authors.lastname: Takishima
mesh_terms: D000818:Animals; D003326:Coronary Circulation; D003327:Coronary Disease / Q000503:physiopathology*; D004285:Dogs; D006439:Hemodynamics; D010492:Pericardiectomy; D010496:Pericardium / Q000502:physiology*; D013599:Systole