Rational therapy to reduce mortality and reinfarction following myocardial infarction

Review of postinfarct treatment with verapamil: combined experience of early and late intervention studies with verapamil in patients with acute myocardial infarction. Danish Study Group on Verapamil in Myocardial Infarction

An overview of the published studies on the use of verapamil during and after an acute myocardial infarction is presented. Meta-analyses of the two small early intervention trials, one early intervention trial followed by a 6-month treatment period (The Danish Verapamil Infarction Trial I, DAVIT I) and one late intervention trial (DAVIT II), demonstrated a 17-20% statistically nonsignificant reduction of mortality, first reinfarctions, and first major events. In DAVIT II was found a statistically significant 20% reduction of first major events in verapamil-treated patients. In patients without heart failure during the acute event mortality, first reinfarctions and first major events were significantly reduced by 30-36% in verapamil-treated patients. No difference was found in patients treated for heart failure in the coronary care unit. A meta-analysis based on patients included in DAVIT I alive day 8 and all patients included in DAVIT II demonstrated a statistically significant 21-26% reduction of mortality, first reinfarctions, and first major events.

Hydrogen peroxide-induced oxidative stress to the mammalian heart-muscle cell (cardiomyocyte): nonperoxidative purine and pyrimidine nucleotide depletion

Hydrogen peroxide (H2O2) overload may contribute to cardiac ischemia-reperfusion injury. We report utilization of a previously described cardiomyocyte model (J. Cell. Physiol., 149:347, 1991) to assess the effect of H2O2-induced oxidative stress on heart-muscle purine and pyrimidine nucleotides and high-energy phosphates (ATP, phosphocreatine). Oxidative stress induced by bolus H2O2 elicited the loss of cardiomyocyte purine and pyrimidine nucleotides, leading to eventual de-energization upon total ATP and phosphocreatine depletion. The rate and extent of ATP and phosphocreatine loss were dependent on the degree of oxidative stress within the range of 50 microM to 1.0 mM H2O2. At the highest H2O2 concentration, 5 min was sufficient to elicit appreciable cardiomyocyte high-energy phosphate loss, the extent of which could be limited by prompt elimination of H2O2 from the culture medium. Only H2O2 dismutation completely prevented ATP loss during H2O2-induced oxidative stress, whereas various free-radical scavengers and metal chelators afforded no significant ATP preservation. Exogenously-supplied catabolic substrates and glycolytic or tricarboxylic acid-cycle intermediates did not ameliorate the observed ATP and phosphocreatine depletion, suggesting that cardiomyocyte de-energization during H2O2-induced oxidative stress reflected defects in substrate utilization/energy conservation. Compromise of cardiomyocyte nucleotide and phosphocreatine pools during H2O2-induced oxidative stress was completely dissociated from membrane peroxidative damage and maintenance of cell integrity. Cardiomyocyte de-energization in response to H2O2 overload may constitute a distinct nonperoxidative mode of injury by which cardiomyocyte energy balance could be chronically compromised in the post-ischemic heart.