Protection of the hypertrophied human heart by adjusting regional myocardial temperature to a safe level.
Uneven distribution of temperature and the persistence of electro-mechanical activity after aortic cross-clamping are 2 factors limiting the myocardial protection during cardioplegic arrest, especially in hypertrophied hearts which are known to be extremely vulnerable to ischemia. In the present study regional myocardial temperature (T) was continuously controlled, and the time until arrest occurred (delta t) was determined in 61 patients undergoing aortic valve replacement. In addition, the myocardial contents of high energy phosphates and lactate were assessed. Three different cardioplegic solutions were employed: In the first group we used Bretschneider solution (Br), in the second group St. Thomas' solution (St), and in the third group the so-called "Hamburg cardioplegia" (H). During cardiac arrest the regional myocardial temperature was adjusted to temperatures not exceeding 15 degrees C by intermittent infusions of cold cardioplegic solution. We found a positive correlation between left ventricular muscle mass (LVMM) and delta t. A negative correlation existed between LVMM and adenosine triphosphate (ATP) contents at the end of the ischemic period. The cooling characteristics and delta t were significantly longer and the cooling to 15 degrees C was less rapid when H was used. Adenosine-triphosphate contents were well preserved during ischemia in all 3 groups. We conclude that all 3 cardioplegic solutions tested protect the hypertrophied myocardium adequately if the regional myocardial temperature does not increase above 15 degrees C during cardiac arrest. Hearts with a higher LVMM showed a decreased myocardial ATP content at the end of the ischemic period. Therefore, the LVMM may limit myocardial protection.
H H
HH
Scheld
G
G
Görlach
J
J
Mulch
T
T
Podzuweit
R
R
Höge
F W
FW
Hehrlein
W
W
Schaper
D000255:Adenosine Triphosphate / Q000378:metabolism; D001021:Aortic Valve; D001639:Bicarbonates; D002122:Calcium Chloride; D006332:Cardiomegaly / Q000601:surgery*; D005260:Female; D005947:Glucose; D006324:Heart Arrest, Induced; D006350:Heart Valve Prosthesis; D006801:Humans; D007430:Intraoperative Care; D007773:Lactates / Q000378:metabolism; D019344:Lactic Acid; D008274:Magnesium; D008297:Male; D008353:Mannitol; D008875:Middle Aged; D008991:Monitoring, Physiologic; D009206:Myocardium / Q000378:metabolism; D010725:Phosphocreatine / Q000378:metabolism; D011189:Potassium Chloride; D011343:Procaine; D012965:Sodium Chloride
D001639:Bicarbonates; C039984:Bretschneider cardioplegic solution; D007773:Lactates; C041711:St. Thomas' Hospital cardioplegic solution; D010725:Phosphocreatine; D019344:Lactic Acid; D008353:Mannitol; D012965:Sodium Chloride; D011343:Procaine; D011189:Potassium Chloride; D000255:Adenosine Triphosphate; D008274:Magnesium; D005947:Glucose; D002122:Calcium Chloride