Decreased contractility and compliance of the left ventricle as complications of thermal trauma.
To test the hypothesis that systemic complications of dermal burns encompass dysfunction of myocardial contractile mechanisms, we studied contraction-relaxation properties of isovolumic left ventricular (LV) preparations isolated from guinea pigs 24 hours after full-thickness burn to approximately 47% total body surface area. Compared to control hearts, hearts from burned subjects consistently generated significantly lower values for LV systolic pressure (94 +/- 2 vs 66 +/- 2 mm Hg; p less than 0.001) and maximal rates of LV pressure rise (+ dP/dtmax; 1296 +/-71 vs 1091 +/- 46 mm Hg X sec-1; p less than 0.05) and fall (-dP/dtmax; 1214 +/- 45 vs 856 +/- 34 mm Hg X sec-1; p less than 0.001). The LV contractile deficit of burn hearts was not correlated with changes in tissue water content, and it was not surmountable by excess glucose, insulin, increased coronary flow, or maximal preload elevation. In addition, end-diastolic pressure-volume relationships in burn hearts were shifted upward and to the left of controls in the direction of decreased compliance (p less than 0.05 to p less than 0.01). Thus, LV sequelae of thermal trauma manifest in isolated hearts as decreased contractility, slowed isovolumic relaxation, and decreased diastolic compliance; in the intact animal this combination would reduce ejection and impede filling of the ventricle, with diastolic pressures reflecting changes in compliance as well as in contractile function.
D000241:Adenosine / Q000494:pharmacology; D000818:Animals; D001794:Blood Pressure; D002056:Burns / Q000503:physiopathology*; D003326:Coronary Circulation; D003971:Diastole; D005947:Glucose / Q000494:pharmacology; D006168:Guinea Pigs; D006321:Heart / Q000503:physiopathology*; D006339:Heart Rate; D007328:Insulin / Q000494:pharmacology; D008297:Male; D009200:Myocardial Contraction; D014655:Vascular Resistance
D007328:Insulin; D005947:Glucose; D000241:Adenosine