Infarct size as estimated from peak creatine kinase and lactate dehydrogenase is probably reduced in patients using calcium antagonists at the onset of symptoms

In animal models, calcium antagonists (Ca-A) administered before ischemia and reperfusion reduced myocardial necrosis, attenuated postischemic contractile dysfunction, and reduced tissue calcium. In 753 patients with acute myocardial infarction (AMI), we examined if use of Ca-A at the onset of symptoms (n = 127 patients) reduced infarct size as estimated from peak creatine kinase (CKmax) and lactate dehydrogenase (LDmax) activities. The study had an observational exposed/nonexposed design, and both crude and adjusted effects were investigated. Crude effects: In the restricted cohort of patients not receiving thrombolytic treatment (thr- pts; n = 411 patients), CKmax and LDmax were lower in Ca-A+ patients than in Ca-A- patients, being 643 versus 887 U/l (2 p = 0.004) and 708 versus 867 U/l (2 p = 0.005), respectively. When using log (CKmax) and log (LKmax) as outcomes, the same results were found (2 p = 0.002). More of the restricted cohort of the pts used Ca-A in the lower quartiles of CKmax and LDmax (p for linear trend = 0.005 and 0.004 for CKmax and LDmax, respectively). Adjusted effects: Thrombolysis was an effect modifier of the association between Ca-A and peak enzyme levels. In thr-pts, the coefficients of Ca-A were negative and borderline significant for log (CKmax; 2 p = 0.088) and negative and highly significant for log (LDmax; 2 p = 0.010) when adjusting for confounders. The present observational study indicates that the use of a Ca-A at the onset of AMI reduces infarct size, as estimated from CKmax and LDmax activities.