Observations in patients with functional mutations of the norepinephrine transporter (NET) gene suggest that impaired norepinephrine uptake may contribute to idiopathic orthostatic intolerance.

The ischemic preconditioning response among elderly patients is known to be lower than in adult patients. Since mitochondrial ATP-sensitive potassium (K(ATP)) channels exert preconditioning effects, we undertook this study to determine whether this attenuated activation of K(ATP) channels influences the reduced responsiveness of elderly patients to ischemic preconditioning.

The application of previous magnetic resonance (MR) angiography techniques has enabled noninvasive differentiation between patent and occluded coronary artery bypass grafts. However, the detection of graft stenosis remains difficult. The purpose of our study was to determine the accuracy of high-resolution navigator-gated 3-dimensional (3-D) MR angiography in detecting vein graft disease. Methods and Results- MR angiography was performed in addition to coronary angiography with quantitative coronary analysis in 56 vein grafts from 38 patients (mean age 66.6+/-9.3 years), who presented with recurrent chest pain after bypass surgery. Eighteen grafts showed a luminal stenosis >/=50%, 11 grafts a stenosis >/=70%, and 6 grafts were occluded. All MR angiograms were evaluated independently by 2 blinded observers, who scored the presence of graft occlusion and graft stenosis >/=50% and >/=70% with a confidence level of 1 to 10. MR image quality was judged as insufficient in 6 grafts and these were excluded. Receiver-operator characteristic analysis revealed an area under the curve of 0.89 and 0.89 for identifying graft occlusion, 0.81 and 0.87 for stenosis >/=50%, and 0.82 and 0.79 for stenosis >/=70% for the 2 observers, respectively. Interobserver agreement in assessing graft occlusion and stenosis >/=50% and >/=70% was 94% (kappa=0.74, r=0.81), 72% (kappa=0.40, r=0.66), and 82% (kappa=0.53, r=0.72), respectively.

Patients with prior CABG with a subsequent non-ST-segment elevation acute coronary syndrome (ACS) pose an increasingly important clinical problem. Although GP IIb/IIIa inhibitors have improved the outcome of patients with ACS, their efficacy in patients with prior CABG has not been previously evaluated. Methods and Results- We analyzed the 30- and 180-day outcomes of patients with prior CABG enrolled in the Platelet Glycoprotein IIb/IIIa in Unstable Angina: Receptor Suppression Using Integrilin Therapy (PURSUIT) trial. In this trial, which evaluated the efficacy of eptifibatide in patients with ACS, 1134 patients (12%) with prior CABG and 8321 without prior CABG were enrolled. After adjusting for differences in baseline characteristics and treatment, patients with prior CABG had a significantly higher mortality rates at 30 days (hazard ratio [HR], 1.45 [95% CI, 1.06 to 1.98]; P=0.019) and at 180 days (HR, 1.32 [95% CI, 1.04 to 1.67]; P=0.021). At 30 days, there was a similar effect on the primary end point of death or myocardial infarction in the eptifibatide group versus the placebo group in prior CABG patients (unadjusted HR, 0.90 [95% CI, 0.67 to 1.20]) and in patients without a history of CABG (unadjusted HR, 0.89 [95% CI, 0.80 to 0.99]).

Platelet glycoprotein IIb/IIIa inhibitors reduce the rate of death or myocardial infarction among patients with acute coronary syndromes without persistent ST-segment elevation, but their effects may depend on plasma concentrations. We tested whether the addition of lamifiban, titrated to achieve target plasma concentrations, to standard care would improve clinical outcomes.

This study compares the effect of estrogens and ACE inhibition on plasminogen activator inhibitor-1 (PAI-1) concentrations in healthy postmenopausal women, genotyped for a 4G/5G polymorphism in the PAI-1 promoter, a polymorphism shown to influence PAI-1 concentrations. Methods and Results- Morning estradiol, PAI-1, tissue plasminogen activator, plasma renin activity, angiotensin II, and aldosterone were measured in 19 postmenopausal women (5G/5G:4G/5G:4G4G=5:10:4, respectively) at baseline and during randomized, single-blind, crossover treatment with conjugated equine estrogens 0.625 mg per os per day, ramipril 10 mg per os per day, and combination estrogens and ramipril. Estradiol (P<0.005) and angiotensin II (P<0.01) were significantly higher during estrogens. Plasma renin activity was significantly increased during ACE inhibition (P<0.05). Both conjugated estrogens [PAI-1 antigen from 12.5 (7.6, 17.4) [mean (95% CI)] baseline to 6.6 (2.6, 10.7) ng/mL, P<0.01] and ACE inhibition [8.3 (4.9, 11.7) ng/mL, P<0.005] decreased PAI-1 without decreasing tissue plasminogen activator. The effect of combined therapy on PAI-1 [5.6 (2.3, 8.8) ng/mL] was significantly greater than that of ramipril alone (P<0.05). There was a significant effect of PAI-1 4G/5G genotype on baseline PAI-1 concentrations (P=0.001) and a significant interactive effect of 4G/5G genotype and treatment, such that genotype influenced the change in PAI-1 during ramipril (P=0.011) or combined therapy (P=0.006) but not during estrogens (P=0.715).

The TIMI myocardial perfusion grade (TMPG) and ST-segment resolution both reflect perfusion and are associated with mortality after thrombolysis for acute myocardial infarction. We hypothesized that these measures would also be associated with infarct size by single photon emission computed tomography (SPECT). Methods and Results- In the LIMIT AMI trial (Limitation of Myocardial Injury following Thrombolysis in Acute Myocardial Infarction) of lytic monotherapy versus lytic plus rhuMAb CD18, early 90-minute TMPG (n=221) and ST segment resolution (n=242) were compared with subsequent SPECT Technetium-99 m Sestamibi, measuring the percentage of the left ventricle with no Sestamibi uptake. Infarct sizes were larger with TMPG 0 or 1 (a closed or stained myocardium) than with TMPG 2 or 3 (open myocardium, median 13% versus 7%, P=0.004). Infarcts were also larger in patients with no ST segment resolution (median 15%) or incomplete resolution (11%) than in those with complete resolution (6%, overall P=0.0001). The difference in infarct size by TMPG persisted when stratified by category of ST resolution.

In acute myocardial infarction (AMI), surface-bound tissue factor pathway inhibitor-1 (TFPI-1) inhibits an increased monocyte procoagulant activity. In addition, TFPI-1 is released from microvascular endothelial cells after treatment with heparin and thereby contributes to its antithrombotic properties.

The Fontan procedure is the definitive operation for palliation of complex congenital heart disease with single-ventricle physiology. Fenestration of the Fontan circuit allows for shunting of deoxygenated blood to the systemic circulation. This procedure improved the clinical outcomes of patients who are at high risk for poor Fontan results. However, it is controversial whether fenestration is beneficial for standard-risk patients.

High-resolution MRI has been shown to be capable of distinguishing intact, thick fibrous caps from thin and ruptured caps in human carotid atherosclerosis in vivo. The aim of this study was to determine whether MRI identification of fibrous cap thinning or rupture is associated with a history of recent transient ischemic attack (TIA) or stroke.

Stimulation of coronary collateral growth has potential clinical value, yet techniques to assess such growth in patients are limited.

Recent studies indicate that MRI, after administration of gadolinium-diethylenetriamine pentaacetic acid, can identify nonviable areas in dysfunctional myocardium. We compared MRI hyperenhancement with PET as a gold standard for detection and quantification of myocardial scar tissue.

The aim of the present study was to determine the use of cyclic variation in ultrasonic integrated backscatter (IBS), which is reduced in ischemic myocardium, to predict an occluded infarct-related artery (IRA) after thrombolysis for acute myocardial infarction (AMI). This is important, because patency of the IRA 90 minutes after thrombolysis has been shown to predict outcome.

Asymptomatic reductions in arterial pressure have been reported to occur before the onset of tilt-induced syncope. We investigated the predictive value of these reductions for a positive tilt result.

It is well established that a depressed baroreflex sensitivity may adversely influence the prognosis in patients with chronic heart failure (CHF) and in those with previous myocardial infarction.

Homocysteine is a risk factor for coronary artery disease (CAD), although a causal relation remains to be proven. The importance of determining direct causality rests in the fact that plasma homocysteine can be safely and inexpensively reduced by 25% with folic acid. This reduction is maximally achieved by doses of 0.4 mg/d. High-dose folic acid (5 mg/d) improves endothelial function in CAD, although the mechanism is controversial. It has been proposed that improvement occurs through reduction in total (tHcy) or free (non-protein bound) homocysteine (fHcy). We investigated the effects of folic acid on endothelial function before a change in homocysteine in patients with CAD.

Coronary endothelial dysfunction may be an early marker for cardiac allograft vasculopathy (CAV) in orthotopic heart transplant recipients. Using serial studies with intravascular ultrasound and Doppler flow-wire measurements, we have previously demonstrated that annual decrements in coronary endothelial function are associated with progressive intimal thickening. The present study tested whether endothelial dysfunction predicts subsequent clinical events, including cardiac death and CAV development.

Although thyroid hormone (TH) exerts relevant effects on the cardiovascular system, it is unknown whether TH also regulates vascular reactivity in humans. Methods and Results- We studied 8 patients with hyperthyroidism, basally (H) and 6 months after euthyroidism was restored by methimazole (EU). Thirteen healthy subjects served as control subjects (C). We measured forearm blood flow (FBF) by strain-gauge plethysmography during intrabrachial graded infusion of acetylcholine, sodium nitroprusside (SNP), norepinephrine, and L-NMMA (inhibitor of NO synthesis). Basal FBF (in mL. dL(-1). min(-1)) was markedly higher in H than in C (5.8+/-1.2 and 1.9+/-0.1, respectively; P<0.001) and was close to normal in EU (2.6+/-0.3, P<0.01 versus H). During acetylcholine infusion, FBF increased much more in H (+33+/-5) than in C (+14+/-3, P<0.01 versus H) and in EU (+20+/-5, P=0.01 versus H and P=NS versus C). In contrast, the response to SNP infusion was comparable in the patients and control subjects. During norepinephrine infusion, the fall in FBF was much more pronounced in H (-6+/-1) than in C (-0.7+/-0.3, P<0.005 versus H) and in EU (-1.5+/-0.3, P<0.01 versus H). Finally, inhibition of NO synthesis by L-NMMA decreased FBF by 2.8+/-0.6, 0.61+/-0.7, and 1.4+/-0.3 in H, C, and EU, respectively (H versus C and EU, P<0.05).

Patients with low HDL cholesterol (HDL-C) and elevated triglyceride had an increased risk for coronary heart disease (CHD) events and received the greatest benefit with fibrate therapy in substudy analyses of the Helsinki Heart Study and the Bezafibrate Infarction Prevention Study.

Cardiac resynchronization therapy (CRT) improves systolic function in heart failure patients with ventricular conduction delay by stimulating the left ventricle (LV) or both ventricles (biventricular, BV). Optimal LV site selection is of major clinical interest for CRT device implantation; however, the dependence of hemodynamics on LV stimulation site has not been established. Thus, the objective of this study was to compare the hemodynamic response to CRT for 2 LV coronary vein sites: the free wall and anterior wall. Methods and Results- A total of 30 patients (mean NYHA class, 2.7; mean QRS interval, 152 ms; mean PR interval, 194 ms) enrolled in the PATH-CHF-II trial were studied. CRT was administered with LV and BV stimulation in VDD mode at 4 AV delays. LV stimulation was at the lateral free wall or anterior wall, whereas right ventricular stimulation was fixed near the apex. LV+dP/dt(max) and aortic pulse pressure changes from baseline during CRT were compared for LV sites. Free wall sites with LV and BV stimulation yielded significantly larger LV+dP/dt(max) (14% versus 6%, P<0.001 for LV; 12% versus 5%, P<0.001 for BV) and pulse pressure (8% versus 4%, P<0.001 for LV; 9% versus 5%, P<0.001 for BV) compared with anterior sites. In one third of patients, CRT at free wall sites increased LV+dP/dt(max), whereas it decreased at anterior sites over most AV delays.