Varespladib methyl in cardiovascular disease.

IMPORTANCE OF THE FIELD: The high risk of recurrent cardiovascular events amongst patients with cardiovascular disease receiving evidence-based therapies has prompted investigations into complimentary treatments that may reduce residual risk. Analyses of clinical trials in statin-treated patients demonstrate that elevated lipid levels and an activated systemic inflammatory state are associated with a higher risk of recurrent cardiovascular events. AREAS COVERED IN THIS REVIEW: This article reviews evidence supporting the causal role for secretory phospholipase A(2) (sPLA(2)) in experimental atherosclerosis, the involvement of various sPLA(2) isozymes as mediators of pro-atherogenic lipoprotein remodeling and participants in vascular and systemic inflammatory responses, and the evidence that sPLA(2) inhibition reduces atherosclerosis in experimental models and biomarkers associated with cardiovascular events in coronary heart disease (CHD) patients. WHAT THE READER WILL GAIN: The experimental basis for sPLA(2) inhibition with varespladib methyl as a potential candidate for lowering recurrent cardiovascular events particularly in acute coronary syndrome patients is discussed. TAKE HOME MESSAGE: Varespladib methyl therapy reduces atherogenic lipoprotein concentrations and systemic inflammatory markers in CHD patients. The future role of varespladib methyl in CHD patients awaits the results of ongoing clinical trials.

A mechanistic approach to assess the proarrhythmic risk of QT-prolonging drugs in preclinical pharmacologic studies.

Drugs with diverse structures and from several therapeutic classes are reported to increase the risk that a patient will experience ventricular tachyarrhythmias (e.g., torsades de pointes [TdP]) during drug therapy. This review discusses the use of preclinical assays to assess the risk that a QT-prolonging drug will cause TdP. The mechanisms underlying the development of TdP and the factors that increase the risk of TdP are described and applied to the design of preclinical experimental models for detection of proarrhythmic drug actions. Recommended assays, conditions, and preparations for preclinical assessment of the drug-induced risk to TdP are given. No single preparation can simulate all conditions that cause TdP in patients. However, the assays described herein are capable of detecting the proarrhythmic effects of currently used drugs, even when these effects are reported to be extremely rare in clinical practice.

Electrophysiologic properties and antiarrhythmic actions of a novel antianginal agent.

Ranolazine is a novel antianginal agent capable of producing anti-ischemic effects at plasma concentrations of 2 to 6 microM without a significant reduction of heart rate or blood pressure. This review summarizes the electrophysiologic properties of ranolazine. Ranolazine significantly blocks I(Kr) (IC(50) = 12 microM), late I(Na), late I(Ca), peak I(Ca), I(Na-Ca) (IC(50) = 5.9, 50, 296, and 91 microM, respectively) and I(Ks) (17% at 30 microM), but causes little or no inhibition of I(to) or I(K1). In left ventricular tissue and wedge preparations, ranolazine produces a concentration-dependent prolongation of action potential duration (APD) in epicardium, but abbreviation of APD of M cells, leading to either no change or a reduction in transmural dispersion of repolarization (TDR). The result is a modest prolongation of the QT interval. Prolongation of APD and QT by ranolazine is fundamentally different from that of other drugs that block I(Kr) and induce torsade de pointes in that APD prolongation is rate-independent (ie, does not display reverse rate-dependent prolongation of APD) and is not associated with early after depolarizations, triggered activity, increased spatial dispersion of repolarization, or polymorphic ventricular tachycardia. Torsade de pointes arrhythmias were not observed spontaneously nor could they be induced with programmed electrical stimulation in the presence of ranolazine at concentrations as high as 100 microM. Indeed, ranolazine was found to possess significant antiarrhythmic activity, acting to suppress the arrhythmogenic effects of other QT-prolonging drugs. Ranolazine produces ion channel effects similar to those observed after chronic exposure to amiodarone (reduced late I(Na), I(Kr), I(Ks), and I(Ca)). Ranolazine's actions to reduce TDR and suppress early after depolarization suggest that in addition to its anti-anginal actions, the drug possesses antiarrhythmic activity.