Three-dimensional QCA-based vessel fractional flow reserve (vFFR) in Heart Team decision-making: a multicentre, retrospective, cohort study.

Objectives: To evaluate the feasibility of three-vessel three-dimensional (3D) quantitative coronary angiography (QCA)-based fractional flow reserve (FFR) computation in patients discussed within the Heart Team in whom the treatment decision was based on angiography alone, and to evaluate the concordance between 3D QCA-based vessel FFR (vFFR)-confirmed functional lesion significance and revascularisation strategy as proposed by the Heart Team.

Design: Retrospective, cohort.

Setting: 3D QCA-based FFR indices have not yet been evaluated in the context of Heart Team decision-making; consecutive patients from six institutions were screened for eligibility and three-vessel vFFR was computed by blinded analysts.

Ca(2+) sensitization and diastolic function of normal and stunned porcine myocardium.

Ca(2+) sensitizers prolong myofibrillar force development in vitro and might therefore aggravate relaxation abnormalities of stunned myocardium. This is the first in vivo study of the effects of the thiadiazinone derivative EMD 60263 ((+)-5-(l-(alpha-ethylimino-3, 4-dimethoxybenzyl)-1,2,3,4-tetrahydroquinoline-6-yl)-6-methyl-3, 6-dihydro-2H-1,3,4-thiadiazine-2-on), a Ca(2+)-sensitizing agent with negligible phosphodiesterase III inhibitory activity, on diastolic function of regionally stunned myocardium. After producing stunning by two sequences of 10-min coronary artery occlusion and 30 min of reperfusion, anaesthetised pigs received either saline (n=7) or 1.

Contribution of asynchrony and nonuniformity to mechanical interaction in normal and stunned myocardium.

In anesthetized pigs, we investigated whether asynchrony (delta T) and nonuniformity (regional differences) in contractility (delta E) could describe the interaction between normal and stunned myocardium. Mechanical interaction was evaluated by regional postsystolic work (PSW) before and after production of stunning by a 5-min occlusion of the left circumflex coronary artery [LCX (LCX stunning)] and a subsequent 10-min occlusion of the left anterior descending coronary artery [LAD (LAD stunning)]. delta T and delta E were intensified by intracoronary (LAD) infusions of dobutamine.

Phosphorylation by protein kinase C and the responsiveness of Mg(2+)-ATPase to Ca2+ of myofibrils isolated from stunned and non-stunned porcine myocardium.

Previously we showed in an in situ porcine model that the thiadiazinone derivative [+]EMD 60263, a Ca2+ sensitizer without phosphodiesterase III inhibitory properties, increased contractility more profoundly in stunned than in non-stunned myocardium. This finding was consistent with the observed leftward shifts of the pCa2+/Mg(2+)-ATPase curves of isolated myofibrils induced by [+]EMD 60263. The aim of the present investigation was to study the possible involvement of protein kinase C in the mechanism of reduced Ca2+ responsiveness of myofilaments during stunning.

Cardiac depression after experimental air embolism in pigs: role of addition of a surface-active agent.

Objective: Air bubbles entering the coronary artery may have harmful effects on cardiac function. From the physical point of view it is the relatively high surface tension of the blood-air interface which causes bubbles to trap in small vessels. The aim of the present study was to reduce depression of myocardial function from air embolism by lowering the surface tension of air bubbles.

The effect of a thiadiazinone derived Ca2+ sensitizer on the responsiveness of Mg(2+)-ATPase to Ca2+ in myofibrils isolated from stunned and nonstunned porcine and human myocardium.

Previously, we showed, in an in situ porcine model, that the thiadiazinone derivative [+]EMD 60263, a putative Ca2+ sensitizer with minimal phosphodiesterase III inhibitory properties, increased contractility more profoundly in stunned than in nonstunned myocardium. The aim of the present investigation was to study the mechanism of action by determining the in vitro effects of [+]EMD 60263 on the Ca2+ responsiveness of the Mg(2+)-dependent ATPases of myofibrils and sarcoplasmic reticulum membrane vesicles, isolated from normal ventricle of swine and hypertrophic septum of cardiomyopathic patients. Contamination of the myofibrils with sarcoplasmic reticulum membranes was excluded by testing the effect of the sarcoplasmic reticulum Ca(2+)-pumping ATPase inhibitor thapsigargin.

Assessment of the role of the renin-angiotensin system in cardiac contractility utilizing the renin inhibitor remikiren.

1. The role of the renin-angiotensin system in the regulation of myocardial contractility is still debated. In order to investigate whether renin inhibition affects myocardial contractility and whether this action depends on intracardiac rather than circulating angiotensin II, the regional myocardial effects of systemic (i.

Mechanical efficiency of stunned myocardium is modulated by increased afterload dependency.

Objective: Oxygen consumption (MVO2) of stunned myocardium is relatively high compared to, and poorly correlated with, systolic contractile function. The aim of this study was to investigate whether an increased afterload dependency, induced by the decreased contractility of the stunned myocardium, contributes to the large variability in the mechanical efficiency data.

Methods: In 13 anaesthetised open thorax pigs undergoing two cycles of 10 min occlusion of left anterior descending coronary artery and 30 min reperfusion, segment shortening, the slope of end systolic pressure segment length relationship (Ees), external work (EW, derived from the area inside the left ventricular pressure segment length loop), the efficiency of energy conversion (EET, = EW/PLA x 100%, where PLA = total pressure-segment length area), mechanical efficiency (EW/MVO2), and their dependency on left ventricular end systolic pressure (Pes) were determined before and after induction of stunning, and during subsequent inotropic stimulation with dobutamine (1 and 3 micrograms.

Effect of arterial blood pressure and ventilation gases on cardiac depression induced by coronary air embolism.

In this study the time course of cardiac depression after selective intracoronary injection of air bubbles was investigated in six anesthetized pigs (30 +/- 2 kg) with different mixtures of ventilation gases and different mean arterial blood pressures (MAP). Air bubbles of 150 microns diam were injected into the left anterior descending coronary artery (LADCA) in a volume of 2 microliters/kg body wt. In each animal an injection of air bubbles was applied during ventilation with N2-O2 and a MAP of 77 +/- 3 mmHg (N2-O2/low pressure) or 111 +/- 3 mmHg (N2-O2/high pressure) and during ventilation with pure O2 and a MAP of 77 +/- 3 mmHg (O2/low pressure) or 110 +/- 3 mmHg (O2/high pressure).

Myofibrillar Ca2+ sensitization predominantly enhances function and mechanical efficiency of stunned myocardium.

Background: Myocardial stunning is characterized not only by a decreased regional postischemic function but also by a relatively high oxygen consumption (ie, decreased mechanical efficiency). Several lines of evidence suggest that the underlying mechanism may involve a decreased sensitivity of the myofibrils to calcium, but in vivo evidence is lacking. We therefore evaluated this hypothesis in vivo using EMD 60263, a calcium-sensitizing agent, which is devoid of any phosphodiesterase-inhibiting properties.

Effect of bimakalim (EMD 52692), an opener of ATP sensitive potassium channels, on infarct size, coronary blood flow, regional wall function, and oxygen consumption in swine.

Objective: The aim was to assess whether bimakalim, an opener of ATP sensitive potassium channels, can reduce infarct size in swine myocardium.

Methods: Experiments were performed in open chest pigs subjected to a 60 min occlusion of a branch of the left anterior descending coronary artery and to 2 h reperfusion. Five groups of animals were studied.

End-systolic pressure length relations of stunned right and left ventricles after inotropic stimulation.

Regional end-systolic pressure-segment length relationships (ESPSLR) were used to compare the degree of right and left ventricular stunning induced by a 10-min occlusion of the left anterior descending coronary artery and the response to subsequent atrial pacing (50 beats/min above intrinsic heart rate) without and with dobutamine (2 micrograms.kg-1.min-1) in nine anesthetized open-chest pigs.

Negative inotropy of lidocaine: possible biochemical mechanisms.

Previous studies have shown that lidocaine has a negative inotropic effect on the myocardium. This effect could be mediated by a decrease in O2 supply and/or utilization, or abnormalities in intracellular Ca2+ handling by the myocardium. To investigate which of these mechanisms are involved we studied nine open-chest anaesthetized pigs, which received an infusion of lidocaine (4-16 mg.

Coronary stenting with a new, radiopaque, balloon-expandable endoprosthesis in pigs.

Background: Intracoronary stents may be effective when used as "bail-out" devices for acute complications after percutaneous transluminal coronary angioplasty. Furthermore, preliminary reports have demonstrated some promising results with stents with regard to the reduction of restenosis. Several stent devices are available for preclinical and clinical evaluation.

The central and regional cardiovascular responses to intravenous and intracoronary administration of the phenyldihydropyridine elgodipine in anaesthetized pigs.

1. The central and regional cardiovascular responses to intravenous (0.3, 1.

Arterial stenting with self-expandable and balloon-expandable endoprostheses.

Coronary angioplasty is complicated by acute occlusion (within 24 hours) and late restenosis (within 6 months) in 2-5% and 20-40% of the cases, respectively. Vascular endoprostheses (stents) may provide the cardiologist with a solution to some of these complications. Several stent-devices are now available for experimental and clinical evaluation.

Nicorandil and cardiovascular performance in anaesthetized pigs with a concentric coronary artery stenosis.

The present investigation compares the systemic and regional haemodynamics in nicorandil-treated and solvent-treated pigs with a concentric stenosis around the left anterior descending coronary artery. The stenosis per se led to a decrease in mean arterial blood pressure, cardiac output, stroke volume, maximum rate of rise in left ventricular pressure and transmural (more marked in the endocardium than in the epicardium) blood flow to and myocardial wall motion in the post-stenotic segment. Infusions of nicorandil (15 and 30 micrograms.