Postoperative conduction disturbances: a comparison of blood and crystalloid cardioplegia.

Conduction system disturbances after cardioplegia are well described. Our four-man group changed in mid-1987 from standard crystalloid cardioplegia (35 mEq/L of KCl) to blood cardioplegia (4 parts blood to 1 part cardioplegia) (18 mEq/L of KCl) based on experimental and clinical evidence that blood cardioplegia provides better myocardial protection. Shortly thereafter, we anecdotally noted increased conduction abnormalities. This prompted us to compare serially all patients undergoing coronary artery bypass grafting during 1987 for perioperative and late conduction system disturbances after either crystalloid or blood cardioplegia. Surgeons and techniques including topical cooling did not differ. Forty-one (23%) of 179 patients with crystalloid cardioplegia had conduction disturbances versus 141 (49%) of 289 patients with blood cardioplegia (p less than 0.001). Perioperative complete heart block requiring atrioventricular sequential pacing occurred in 20 patients with crystalloid cardioplegia versus 67 patients with blood cardioplegia (p less than 0.002), and atrioventricular block requiring permanent pacing was present in 4 and 12 patients (p less than 0.001), respectively. Left bundle-branch block was found in 8 patients given crystalloid cardioplegia and 28 patients with blood cardioplegia (p less than 0.05); right bundle-branch block, 12 and 68 patients (p less than 0.001); left anterior hemiblock, 8 and 37 patients (p less than 0.001); and interventricular conduction delay, 15 and 53 patients (p less than 0.005), respectively. Bifascicular block occurred in 4 patients receiving crystalloid cardioplegia versus 23 receiving blood cardioplegia (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)