Cardioplegic solutions for myocardial preservation: analysis of hypothermic arrest, potassium arrest, and procaine arrest.

Separate effects of perfusion hypothermia, potassium arrest, and procaine arrest were studied in 150 hearts using the isolated rat heart preparation. Aortic flow rate (AFR), coronary flow rate (CFR), and heart rate (HR) were measured before and after ischemic periods of 90 to 300 min. Prior to the ischemic period, the aortic root was infused with Krebs-Henseleit buffer (KHB), buffer with 30 mEq KCl/L (KHB + K), or buffer with 0.2% procaine (KHB + P), at 15 degrees or 5 degrees C. During the ischemic period the hearts were maintained at 15 degrees or 5 degrees C in a hypothermic chamber. The three solutions had similar recoveries of AFR at 15 degrees and 5 degrees C following ischemic periods of 90, 180, and 240 min. The KHB + K and KHB + P had better recoveries of AFR than KHB at 5 degrees C and 300 min of ischemia. The KHB + K and KHB + P also caused more rapid arrest and a higher incidence of spontaneous recovery of sinus rhythm. Arrest at 5 degrees C was equal to or superior to arrest at 15 degrees C. Perfusion hypothermia is the main component of cold cardioplegia. The addition of procaine or potassium results in increased functional recovery at extended ischemic times at 5 degrees C, more rapid arrest, and better electrical recovery.