title: Diltiazem as an adjunct to cold blood potassium cardioplegia: a clinical assessment of dose and prospective randomization.
abstract: Diltiazem was evaluated as an adjunct to cold blood potassium cardioplegia in 63 patients undergoing elective coronary artery bypass grafting. The dual-phase study compared incrementally increasing doses (50, 100, and 150 micrograms/kg) of diltiazem using a single-blind, randomized schedule with an equivalent volume of placebo added to each of three infusions of cold (10 degrees C +/- 2 degrees C) blood containing potassium chloride at 25 mEq/L for the initial infusion (400 ml) and at 12 mEq/L for the next two infusions (300 ml each). Observations included a number of operative variables, creatine kinase (CK)-MB curves, two-dimensional echocardiography, and pulsed Doppler sonography before operation and on postoperative days 1 and 5. Pulmonary artery thermistor catheter responses were observed for 16 hours postoperatively, as were left ventricular micromanometer-tipped catheter responses in 7 patients. As the dose of diltiazem was increased, there was increasing time to atrioventricular node refunction (23.6 to 62.0 minutes). Diltiazem at 100 micrograms/kg (D-100) resulted in a significantly lower peak CK-MB activity than its placebo. Peak - dp/dt increased in treated patients and decreased in patients given the placebo. The cardiac index in D-100 patients was greater on the first postoperative day than preoperatively. The stroke index returned to the control level by the fifth postoperative day in D-50 and D-100 patients only, and it remained depressed in placebo patients. Although few benefits were realized from the addition of diltiazem to cold blood potassium cardioplegia, there was dose-related prolongation of the atrioventricular node recovery time, which required cardiac pacing and thus was associated with its attendant risks.
mesh_terms: D001026:Coronary Artery Bypass; D003327:Coronary Disease / Q000517:prevention & control*; D003402:Creatine Kinase / Q000032:analysis; D004110:Diltiazem / Q000627:therapeutic use*; D006324:Heart Arrest, Induced / Q000009:adverse effects; D006439:Hemodynamics; D006801:Humans; D007527:Isoenzymes; D009203:Myocardial Infarction / Q000201:enzymology; D011188:Potassium; D011897:Random Allocation
chemical_list: D007527:Isoenzymes; D003402:Creatine Kinase; D004110:Diltiazem; D011188:Potassium