Control of Ca2+ influx by manipulation of Ca2+ and/or Ca2+ antagonist in cardioplegic arrest.
Maximum deactivation of the contractile elements using Ca2+ minimizes oxygen requirements during global ischemia, Ca2+ antagonists and Ca(2+)-free cardioplegia solutions are methods by which the Ca2+ flux can be manipulated. This study was performed with 5 experimental groups: 1) Standard cardioplegia (with Ca2+), 2) Ca(2+)-free cardioplegia, 3) Ca(2+)-free cardioplegia plus verapamil (0.5 mg/L), 4) Verapamil cardioplegia (with Ca2+), and 5) Ca(2+)-free cardioplegia, in which verapamil was administered at the onset of reperfusion (0.5 mg/L). Cardiac functions, heart rate, edema formation, and creatine kinase concentration were measured before and after 70 min of ischemia at a myocardial temperature of 20 degrees C. Ca(2+)-free cardioplegia may be beneficial under hypothermic conditions, but the "Ca2+ paradox" was still a matter of concern. Reperfusion with verapamil did not protect from reperfusion-related injuries. However, the use of verapamil provided more protection than did standard or Ca(2+)-free cardioplegic solutions. Since verapamil did not maintain membrane integrity during ischemia when combined with Ca(2+)-free cardioplegic solutions (prominent edema formation was observed), its combination with Ca(2+)-containing cardioplegic solutions is recommended.
Division of Thoracic and Cardiovascular Surgery, Mayo Clinic, Rochester, Minnesota.
K
K
Hashimoto
K ]
K]
Hahimoto K [corrected to Hashimoto
J P
JP
Mashburn
R
R
Cartier
H V
HV
Schaff
D000818:Animals; D016275:Atrial Function; D001834:Body Water / Q000502:physiology; D002118:Calcium / Q000032:analysis; D002121:Calcium Channel Blockers / Q000494:pharmacology; D015220:Calcium Channels / Q000502:physiology*; D002314:Cardioplegic Solutions / Q000737:chemistry / Q000494:pharmacology; D003402:Creatine Kinase / Q000378:metabolism; D003971:Diastole / Q000502:physiology; D006324:Heart Arrest, Induced / Q000379:methods*; D006339:Heart Rate; D009200:Myocardial Contraction / Q000502:physiology; D017202:Myocardial Ischemia / Q000201:enzymology; D009206:Myocardium / Q000737:chemistry / Q000378:metabolism; D010101:Oxygen Consumption; D011817:Rabbits; D013599:Systole / Q000502:physiology; D016276:Ventricular Function
D002121:Calcium Channel Blockers; D015220:Calcium Channels; D002314:Cardioplegic Solutions; D003402:Creatine Kinase; D002118:Calcium