[Protection of the two types of severely hypertrophied myocardium induced by pressure-loading and by volume...

Although the difficulty of preserving hypertrophied myocardium from induced arrest during aortic clamping has long been recognized, the difference of response to ischemia between the two types of hypertrophy induced by pressure-loading (P) and by volume overloading (V) has not been fully elucidated. In the present study, to assess the two types of hypertrophied myocardium we investigated the 44 patients undergoing valve replacement; the 23 patients of aortic stenosis (AS) without aortic regurgitation (AR), and the 21 patients of AR without AS. The patients of AS (group-P) were divided into two groups regarding the thickness of posterior wall of left ventricle; over 15 mm in P-1 and under 15 mm in P-2. The patients of AR (group-V) were also divided into two groups, which is, preoperative LVEDVI over 250 ml/m2 in V-I and under 250 ml/m2 in V-2. In all four groups myocardial temperature was kept about 5 degrees C with GIK and continuous cold blood coronary perfusion during aortic clamping time. There was no operative death. Postoperative serum enzymes (GOT and CPK) in P-1 were higher than in P-2. Per cent increase of LVEF in P-1 were greater than P-2 and V-1 greater than V-2, respectively. Postoperative catecholamines needed for P-1 was greater than P-2.(ABSTRACT TRUNCATED AT 250 WORDS)