Adenosine instead of supranormal potassium in cardioplegia: it is safe, efficient, and reduces the incidence of postoperative atrial fibrillation. A randomized clinical trial.

Objective: We aimed to evaluate the efficacy and safety of a cold crystalloid cardioplegic solution with adenosine (1.2 mmol/L) instead of supranormal potassium.

Methods: Sixty low-risk patients scheduled for elective coronary artery bypass grafting (CABG) were randomized to receive standard cold crystalloid hyperkalemic cardioplegia (hyperkalemic group) or normokalemic cardioplegia in which supranormal potassium was replaced with 1.

Pretreatment with the nitric oxide donor SNAP or nerve transection blocks humoral preconditioning by remote limb ischemia or intra-arterial adenosine.

We have previously shown that remote ischemic preconditioning (rIPC) by transient limb ischemia leads to the release of a circulating factor(s) that induces potent myocardial protection. Intra-arterial injection of adenosine into a limb also leads to cardioprotection, but the mechanism of its signal transduction is poorly understood. Eleven groups of rabbits received saline control or rIPC or adenosine administration with additional pretreatment with the nitric oxide (NO) synthase blocker N(G)-nitro-l-arginine methyl ester, the NO donor S-nitroso-N-acetylpenicillamine, its non-NO-donating derivative N-acetylpenicillamine, or femoral nerve section.

Adenosine protects against hypoxic injury at hypothermia in guinea pig papillary muscles.

Objectives: To investigate the protective effects of adenosine against hypoxic injury at hypothermia; both magnitude and mechanisms.

Design: Receptor versus non-receptor dependent mechanisms in cardioprotection by adenosine were examined in guinea pig papillary muscles exposed to glucose free hypoxia at 24 degrees C. Contractile force amplitude (CFA) and action potential duration (APD) during increasing concentrations of adenosine at 37 degrees C, 30 degrees C and 24 degrees C normoxia were also examined.

Unilateral adrenal haemorrhage following systemic thrombolysis.

We report a case of unilateral adrenal bleeding, worsened or initiated by systemic thrombolytic therapy given for a suspected myocardial infarction. Initial clinical diagnosis was ruptured aortic aneurysm or aortic dissection. A preoperative contrast-enhanced computer tomography (CT) scan showed a possible bleeding from the left adrenal gland.

Clinical testing of nicorandil supplemented normokalemic cardioplegic solution.

Does nicorandil instead of supranormal potassium safely provide cardioplegia and cardioprotection in humans? Fifty patients eligible for coronary artery surgery were randomly divided into two groups; one group received standard St Thomas' Hospital solution (STHS) and the other group got a crystalloid solution in which supranormal potassium was replaced with 0.2 mmol/l nicorandil. We measured time to arrest, rhythm abnormalities, pre- and postoperative troponin-T, CK-MB and myoglobin release as well as hemodynamic parameters.

Adenosine instead of supranormal potassium in cardioplegic solution improves cardioprotection.

Objective: To determine whether adenosine instead of supranormal potassium in cold crystalloid cardioplegia gives satisfactory cardiac arrest and improved cardioprotection. Cold crystalloid cardioplegia with adenosine, procaine and magnesium (A) was compared with standard cold crystalloid hyperkalemic cardioplegia (K).

Methods: Sixteen pigs were randomized to receive either cold K (n=8) or A (n=8), where hyperkalemia was substituted with 1.

Mechanical restitution curves: a possible load independent assessment of contractile function.

Objective: The time constant of mechanical restitution (T((MRC))), proposed to reflect changes in calcium release and uptake, has been shown to increase in left ventricular (LV) failure, and might have a potential as an index of contractile function. However, in vivo studies of the effect on T((MRC)) of changing loading conditions in the normal and failing heart have not been reported. Consequently, in this study, we tested the hypothesis that the increase in T((MRC)) in vivo is independent of preload and afterload.

Contractile recovery of heart muscle after hypothermic hypoxia is improved by nicorandil via mitochondrial K(ATP) channels.

Background: The ATP-sensitive potassium channel (K(ATP)) opener nicorandil used instead of potassium in hypothermic cardioplegia significantly improves preservation of cardiac function and energetics in the in situ heart preparation. The present study, therefore, examines the effect of nicorandil at different temperatures and the role of sarcolemmal and mitochondrial K(ATP) channels under ex vivo conditions using contractile force (CF) and action potential duration (APD) as end points.

Methods: Guinea-pig papillary muscles at 37, 27, or 22 degrees C (1Hz) were exposed to nicorandil 0.

Mechanical restitution curves reflect post-ischemic stunning in pigs.

Objectives: The time constant of mechanical restitution (T(MRC)), proposed to reflect changes in calcium release and uptake, has been shown to increase in left ventricular (LV) failure. In this study, we tested the hypothesis that T(MRC) also can identify post-ischemic, reversible LV dysfunction (stunning).

Design: Stunning was induced by a series of left main coronary artery occlusions in eight anesthetized open chest pigs.

Nitric oxide synthase inhibition impairs myocardial efficiency and ventriculo-arterial matching in acute ischemic heart failure.

Background And Aims: The effect of nitric oxide (NO) manipulation in acute heart failure has not been sufficiently investigated. Therefore, we assessed the impact of NO-synthase (NOS) inhibition on left ventricular (LV) function and energetics as well as overall hemodynamics, in a porcine model of acute ischemic LV failure.

Methods: Acute heart failure was induced by left coronary artery microembolization in fourteen anesthetized pigs.

Intraaortic balloon pumping improves hemodynamics and right ventricular efficiency in acute ischemic right ventricular failure.

Background: Left ventricular unloading has a potentially deleterious effect in right ventricular failure as a result of altered septal interplay. However, a positive effect of an intraaortic balloon pump during right ventricular failure has been suggested. We investigated the impact of intraaortic balloon pumping on hemodynamics and both left and right ventricular function in an experimental model of isolated right ventricular failure.

Mechanoenergetic inefficiency in the septic left ventricle is due to enhanced oxygen requirements for excitation-contraction coupling.

Objective: Myocardial oxygen consumption (MVO2) in the septic myocardium is increased despite reduced left ventricular mechanical work. We investigated the mechanism behind this energetic inefficiency in the septic myocardium.

Methods: To clarify whether energy consumption in basal metabolism or excitation-contraction (EC) coupling is elevated in the septic myocardium, we separated MVO2 used for these two processes.

Replacing potassium with nicorandil in cold St. Thomas' Hospital cardioplegia improves preservation of energetics and function in pig hearts.

Background: To determine whether the adenosine triphosphate-sensitive potassium channel opener nicorandil, instead of potassium in cold crystalloid cardioplegia, may enhance cardioprotection, crystalloid cardioplegia with nicorandil, magnesium, and procaine was compared with standard crystalloid cardioplegia in terms of left ventricular performance and efficiency.

Methods: Sixteen pigs were randomly assigned to receive cold hyperkalemic crystalloid cardioplegia (n = 8) or nicorandil in cold saline (n = 8). Cold (4 degrees C) cardioplegic solutions were given antegradely and intermittently, with a cross-clamp time of 60 minutes.

Vasodilation and mechanoenergetic inefficiency dominates the effect of the "Ca(2+)-sensitizer" MCI-154 in intact pigs.

Objective: Ca(2+)-sensitizing agents hold potential as ideal cardiac inotropes, but effects in intact animals are scarcely described. We evaluated a pyridazinone derivative, MCI-154, for hemodynamic, inotropic, mechanoenergetic and oxidative metabolic effects.

Design: Intracavitary left ventricular (LV) pressure and conductance (volume) was assessed in open chest anesthetized pigs (n = 6).