Nitroglycerin use and adverse clinical outcomes in elderly patients with acute coronary syndrome

OBJECTIVE

The primary care for acute coronary syndrome (ACS) includes the administration of nitroglycerin (GTN). This study aimed to investigate the association between the use of GTN before percutaneous coronary intervention (PCI) for ACS and clinical outcomes.

METHODS

Nine-hundred and forty-seven patients who underwent PCI for ACS were examined and classified into two groups: those who were treated with GTN before PCI (GTN group) and those who were not (non-GTN group). The incidence of major adverse cardiovascular events (MACE), which consist of all-cause mortality, non-fatal myocardial infarction, stroke and rehospitalisation for heart failure at 1 year, was compared between the two groups.

RESULTS

This study identified 289 patients with ACS who used GTN preceding PCI. Pre-PCI systolic blood pressure was significantly lower in the GTN group than in the non-GTN group (median (IQR); 132.0 (110.0-143.5) mm Hg vs 134.0 (112.0-157.0) mm Hg, respectively, p=0.03). Multivariate Cox regression analysis indicated that GTN use preceding PCI showed an independent association with the incidence of MACE (HR 1.57; 95% CI 1.09-2.28; p=0.016). Overall, the incidence of MACE 1 year after PCI for ACS was significantly higher in the GTN group than in the non-GTN group (log-rank test, p=0.024); however, this trend was consistently found in elderly patients aged ≥75 years (p=0.002) but not in non-elderly patients aged <75 years (p=0.773).

CONCLUSIONS

GTN use preceding PCI for ACS is associated with lower blood pressure and adverse clinical outcomes in elderly patients.

RR interval variability in the evaluation of ventricular tachycardia and effects of implantable cardioverter defibrillator therapy

BACKGROUND

An implantable cardioverter defibrillator (ICD) is the most reliable therapeutic device for preventing sudden cardiac death in patients with sustained ventricular tachycardia (VT). Regarding its effectiveness, targeted VT is defined based on the tachyarrhythmia cycle length. However, variations in RR interval variability of VTs may occur. Few studies have reported on VT characteristics and effects of ICD therapy according to the RR interval variability. We aimed to identify the clinical characteristics of VTs and ICD therapy effects according to the RR interval variability.

METHODS

We analyzed 821 VT episodes in 69 patients with ICDs or cardiac resynchronization therapy defibrillators. VTs were classified as irregular when the difference between two successive beats was >20 ms in at least one of 10 RR intervals; otherwise, they were classified as regular. We evaluated successful termination using anti-tachycardia pacing (ATP)/shock therapy, spontaneous termination, and acceleration between regular and irregular VTs. The RR interval variability reproducibility rates were evaluated.

RESULTS

Regular VT was significantly more successfully terminated than irregular VT by ATP. No significant difference was found in shock therapy or VT acceleration between the regular and irregular VTs. Spontaneous termination occurred significantly more often in irregular than in regular VT cases. The reproducibility rates of RR interval variability in each episode and in all episodes were 89% and 73%, respectively.

CONCLUSIONS

ATP therapy showed greater effectiveness for regular than for irregular VT. Spontaneous termination was more common in irregular than in regular VT. RR interval variability of VTs seems to be reproducible.

A Giant Cardiac Cavernous Hemangioma Involving the Left Atrial Roof in an Elderly Woman

Cardiac tumors are relatively rare, with primary hemangiomas being a particularly rare benign neoplasm. Herein, we report a case of a symptomatic cardiac tumor detected via echocardiography in an 82-year-old woman. Although we performed advanced imaging examinations for her heart, we could not diagnose the tumor before surgery. Eventually, a tumor involving the left atrial roof was detected, and it was completely resected to relieve her symptoms and establish a precise diagnosis. Histopathological examination indicated a cardiac cavernous hemangioma. The patient exhibited an uneventful recovery without any complications.

Impact of short-acting loop diuretic doses and cardiac sympathetic nerve abnormalities on outcomes of patients with reduced left ventricular function

Recent studies reported that high doses of short-acting loop diuretics are associated with poor outcomes in patients with heart failure (HF). Short-acting loop diuretics have been shown to activate the renin-angiotensin system (RAS) and have no favorable effects on cardiac sympathetic nervous system (SNS) activity. The goal of this study is to investigate the relationship between daily doses of furosemide and the outcomes of patients with left ventricular dysfunction (LVD) from the viewpoint of cardiac SNS abnormalities using iodine-123-labeled metaiodobenzylguanidine (l-MIBG) myocardial scintigraphy.We enrolled 137 hospitalized patients (62.5 ± 14.2 years old, 103 men) with LVEF < 45% who underwent l-MIBG myocardial scintigraphy. A delayed heart-to-mediastinum ratio (delayed HMR) was assessed using l-MIBG scintigraphy. Cardiac events were defined as cardiac death or re-hospitalization due to the deterioration of HF. Cox proportional hazard analysis was used to identify predictors of cardiac events.Cardiac events occurred in 57 patients in a follow-up period of 33.1 ± 30 months. In a multivariate Cox proportional hazard analysis, delayed HMR and furosemide doses were identified as independent predictors of cardiac events (P = .0042, P = .033, respectively). Inverse probability of treatment weighting Cox modeling showed that the use of furosemide (≥40 mg /day) was associated with cardiac events with a hazard ratio of 1.96 (P = .003). In the Kaplan-Mayer analysis, the cardiac event-free survival rate was significantly lower in patients treated with high doses of furosemide (≥60 mg/day vs 40-60 mg/day vs <40 mg/day, the Log-rank test P < .0001). In a receiver-operating characteristic (ROC) analysis, the cut-off value for cardiac events was 40 mg/day of furosemide. The cardiac event-free rate was significantly lower in patients with delayed HMR <1.8 (median value) and receiving furosemide ≥40 mg/day than in other patients (the Log-rank test P < .0001). Significant differences in cardiac event rates according to furosemide doses among patients with delayed HMR <1.8 were observed among patients without β-blocker therapy (P = .001), but not among those with β-blocker therapy (P = .127).The present results indicate that a relationship exists between higher doses of furosemide and poor outcomes. The prognosis of HF patients with severe cardiac SNS abnormalities receiving high-dose short-acting loop diuretics is poor.

Superior Rhythm Discrimination With the SmartShock Technology Algorithm - Results of the Implantable Defibrillator With Enhanced Features and Settings for Reduction of Inaccurate Detection (DEFENSE) Trial

BACKGROUND

Shocks delivered by implanted anti-tachyarrhythmia devices, even when appropriate, lower the quality of life and survival. The new SmartShock Technology^®(SST) discrimination algorithm was developed to prevent the delivery of inappropriate shock. This prospective, multicenter, observational study compared the rate of inaccurate detection of ventricular tachyarrhythmia using the SST vs. a conventional discrimination algorithm.Methods and Results:Recipients of implantable cardioverter defibrillators (ICD) or cardiac resynchronization therapy defibrillators (CRT-D) equipped with the SST algorithm were enrolled and followed up every 6 months. The tachycardia detection rate was set at ≥150 beats/min with the SST algorithm. The primary endpoint was the time to first inaccurate detection of ventricular tachycardia (VT) with conventional vs. the SST discrimination algorithm, up to 2 years of follow-up. Between March 2012 and September 2013, 185 patients (mean age, 64.0±14.9 years; men, 74%; secondary prevention indication, 49.5%) were enrolled at 14 Japanese medical centers. Inaccurate detection was observed in 32 patients (17.6%) with the conventional, vs. in 19 patients (10.4%) with the SST algorithm. SST significantly lowered the rate of inaccurate detection by dual chamber devices (HR, 0.50; 95% CI: 0.263-0.950; P=0.034).

CONCLUSIONS

Compared with previous algorithms, the SST discrimination algorithm significantly lowered the rate of inaccurate detection of VT in recipients of dual-chamber ICD or CRT-D.

Coexisting Hyponatremia and Decline in Diastolic Blood Pressure Predispose to Atrial Standstill in Hyperkalemic Patients

BACKGROUND

Atrial standstill is one of the important clinical consequences on the heart in severe hyperkalemia, but it occurs even at modest potassium ion elevation. The extent to which other factors might potentiate the electrocardiographic changes induced by hyperkalemia remains unclear.

METHODS AND RESULTS

This was a retrospective review of the data on 12,639 hospital admissions over a 15-year period. A total of 778 patients with hyperkalemia were identified, 28 of whom had atrial standstill, and had several parameters measured prior to any treatment of hyperkalemia. Patients with atrial standstill were older (P=0.036), had lower diastolic blood pressure (DBP; P<0.0001) and serum sodium concentration (P<0.0001), higher serum potassium (P<0.0001), and high prevalence of angiotensin converting-enzyme inhibitor (ACEI; P=0.009) or mineral corticoid receptor (MR)-blocker (P=0.006), compared with those without atrial standstill. On multivariate logistic regression, DBP <67 mmHg (P=0.006), serum sodium ion <135 mmol/L (P=0.006) and serum potassium ion >6.1 mmol/L (P=0.018) were identified as independent indicators of atrial standstill, after adjusting for sex, age, chronic maintenance hemodialysis, diuretics use or ACEI/angiotensin receptor blocker and MR blocker.

CONCLUSIONS

Hyponatremia and decline in DBP are associated with atrial standstill in patients with hyperkalemia. (Circ J 2016; 80: 1781-1786).

Osteoprotegerin is secreted into the coronary circulation: a possible association with the renin-angiotensin system and cardiac hypertrophy

The circulating osteoprotegerin (OPG) level reflects a series of cardiovascular diseases; however, the source(s) of circulating OPG remain(s) to be determined. This study explored whether OPG is released in the coronary circulation and whether it is associated with cardiac structure and function. Fifty-six patients (67±10 years old, male 57%, hypertension 73%, coronary artery disease 50%) were enrolled, and blood samples were collected simultaneously from the orifice of the left coronary artery (CA) and the coronary sinus (CS) after angiography. The concentration of OPG was higher in the CS than in the CA (7.7±4.1 vs. 6.7±3.6 pmol/l, p<0.001). The trans-cardiac OPG concentration was significantly (p=0.019) decreased in patients who have been prescribed either an angiotensin converting enzyme inhibitor or an angiotensin II type 1 receptor blocker (ACEI/ARB). In patients subgroup who did not take an ACEI/ARB (n=27), the trans-cardiac OPG level was positively correlated with age (r=0.396, p=0.041) and relative wall thickness of left ventricle (r=0.534, p=0.004). In multivariate linear regression analysis, relative wall thickness remained to be the independent variable for the trans-cardiac OPG level (p=0.004). Moreover, trans-cardiac OPG was significantly (p=0.021) increased in patients with relative wall thickness greater than 0.45 but it did not differ if the left ventricular mass index was increased (≥116 for males, or ≥ 104 for females, g/m(2)) or not (p=0.627). This study suggests that OPG is secreted into the coronary circulation and is associated with concentric remodeling/hypertrophy of LV, possibly in interactions with the renin-angiotensin system.

Reduced fractional shortening of right ventricular outflow tract is associated with adverse outcomes in patients with left ventricular dysfunction

Background

Recent studies suggest the significance of right ventricular (RV) function in the outcome in patients with left ventricular dysfunction (LVSD); however, global assessment of RV remains to be determined by echocardiogram because of its complex geometry. This study aimed to validate RV outflow tract fractional shortening (RVOT-FS) in the evaluation of RV function and its prognostic value in patients with LVSD.

Methods

This study included eighty-one patients (62 ± 17 years, mean ± SD, male 79%) with reduced LV ejection fraction (LVEF) (≤40%). Two-dimensional echocardiogram of the parasternal short axis view was obtained at the level of the aortic root, and RVOT-FS was calculated as the ratio of end-diastole minus end-systole dimension to end-diastole dimension.

Results

RVOT-FS ranged from 0.04 to 0.8 (0.3 ± 0.2, mean ± SD), and correlated with LVEF (r = 0.33, p = 0.0028), RV fractional area change (r = 0.37, p = 0.0008) and brain natriuretic peptide level (r = -0.38, p = 0.0005). In Cox multivariate regression analysis, RVOT-FS [hazard ratio (HR) 0.028, 95% confidence interval (CI): 0.002-0.397]; p = 0.008] and New York Heart Association functional class III-IV [HR 2.233, 95% CI: 1.048-4.761]; p = 0.037] were independent factors to predict the events. During a median follow-up period of 319 days (1 to 1862 days), patients with RVOT-FS ≥ 0.2 showed a higher event-free rate than those < 0.2 by Kaplan-Meier analysis (log-rank test, p = 0.0016).

Conclusions

Our data suggest that RVOT-FS is a simple parameter reflecting the severity of both ventricular function in patients with LVSD. In addition, RVOT-FS might be useful to predict adverse outcomes in such a patient population.

Raman-induced Kerr-effect dual-comb spectroscopy

We report on the first (to our knowledge) demonstration of nonlinear dual-frequency-comb spectroscopy. In multi-heterodyne femtosecond Raman-induced Kerr-effect spectroscopy, the Raman gain resulting from the coherent excitation of molecular vibrations by a spectrally narrow pump is imprinted onto the femtosecond laser frequency comb probe spectrum. The birefringence signal induced by the nonlinear interaction of these beams and the sample is heterodyned against a frequency comb local oscillator with a repetition frequency slightly different from that of the comb probe. Such time-domain interference provides multiplex access to the phase and amplitude Raman spectra over a broad spectral bandwidth within a short measurement time.

Adiponectin produced in coronary circulation regulates coronary flow reserve in nondiabetic patients with angiographically normal coronary arteries

BACKGROUND

Epicardial adipose tissue expresses adiponectin protein, and its expression is significantly lower in patients with severe coronary artery disease (CAD) than in those without CAD. Transcoronary adiponectin levels are significantly decreased in nondiabetic but not in diabetic patients with CAD. Adiponectin is also an important adipocytokine that is linked to insulin resistance and reduces coronary microvascular function.

HYPOTHESIS

Adiponectin may play a significant role in the localized coronary circulation. The present study examines the local dynamics of adiponectin in the coronary circulation in nondiabetic individuals with normal coronary arteries and the relationship between adiponectin and coronary microvasculature function.

METHODS

We examined 22 consecutive nondiabetic patients whose coronary arteries were angiographically normal. Plasma levels of adiponectin were measured in blood samples that were simultaneously collected from the orifice of the left coronary artery (LCA) and the great cardiac vein (GCV). To evaluate the function of the coronary microcirculation, we measured coronary flow velocity at maximal hyperemia using a Doppler wire. Coronary flow reserve (CFR) was obtained from the ratio of hyperemia to the baseline coronary flow velocity.

RESULTS

Plasma adiponectin levels in the GCV (median 6.95 microg/ml) were significantly higher than those in the LCA (median 6.60 microg/ml, p < 0.0005). The difference in plasma adiponectin levels between GCV and LCA significantly correlated with CFR (R = 0.451, p < 0.05).

CONCLUSIONS

Adiponectin is locally produced in the coronary circulation. This protein may participate in modulating the coronary circulation of nondiabetic patients with angiographically normal coronary arteries.

Comparison of the electrostatic binding sites on the surface of ferredoxin for two ferredoxin-dependent enzymes, ferredoxin-NADP(+) reductase and sulfite reductase

Plant-type ferredoxin (Fd), a [2Fe-2S] iron-sulfur protein, functions as an one-electron donor to Fd-NADP(+) reductase (FNR) or sulfite reductase (SiR), interacting electrostatically with them. In order to understand the protein-protein interaction between Fd and these two different enzymes, 10 acidic surface residues in maize Fd (isoform III), Asp-27, Glu-30, Asp-58, Asp-61, Asp-66/Asp-67, Glu-71/Glu-72, Asp-85, and Glu-93, were substituted with the corresponding amide residues by site-directed mutagenesis. The redox potentials of the mutated Fds were not markedly changed, except for E93Q, the redox potential of which was more positive by 67 mV than that of the wild type. Kinetic experiments showed that the mutations at Asp-66/Asp-67 and Glu-93 significantly affected electron transfer to the two enzymes. Interestingly, D66N/D67N was less efficient in the reaction with FNR than E93Q, whereas this relationship was reversed in the reaction with SiR. The static interaction of the mutant Fds with each the two enzymes was analyzed by gel filtration of a mixture of Fd and each enzyme, and by affinity chromatography on Fd-immobilized resins. The contributions of Asp-66/Asp-67 and Glu-93 were found to be most important for the binding to FNR and SiR, respectively, in accordance with the kinetic data. These results allowed us to map the acidic regions of Fd required for electron transfer and for binding to FNR and SiR and demonstrate that the interaction sites for the two enzymes are at least partly distinct.

Molecular cloning and sequencing of a cDNA encoding alanine-glyoxylate aminotransferase 2 from rat kidney

Alanine-glyoxylate aminotransferase (AGT) 2 is a pyridoxal 5'-phosphate dependent, mitochondrial enzyme which, in the rat, is expressed at a high level in the kidney. The amino acid sequences of nine tryptic and seven CNBr peptides of the rat kidney AGT2 were determined. Three overlapping cDNAs encoding the AGT2 were cloned on the basis of its partial amino acid sequences by means of a polymerase chain reaction-based approach involving rat kidney poly(A)+ RNA. The complete cDNA sequence comprised 1,919 bases, and contained a 1,536-base open reading frame which encodes a polypeptide of 512 amino acid residues with a putative presequence consisting of 39 amino acid residues at the amino terminus, giving a precursor protein with a molecular mass of 57,150 Da. The sequence of AGT2 exhibits significant homology with neither peroxisomal AGT1 from human liver nor mitochondrial AGT1 from rat liver. However, the sequence of AGT2 exhibited 30.8, 29.2, and 27.1% identity with those of Escherichia coli 4-aminobutyrate aminotransferase, rat ornithine aminotransferase, and Pseudomonas cepacia 2,2-dialkylglycine decarboxylase, respectively. The active site sequences were also well conserved among these aminotransferases. AGT2, thus, is more similar to the other aminotransferases than to AGT1. The results suggest that the rat kidney AGT2 may play a biological role in amino acid metabolism distinct from that of AGT1.

An open reading frame in the Rhodospirillum rubrum plasmid, pKY1, similar to algA, encoding the bifunctional enzyme phosphomannose isomerase-guanosine diphospho-D-mannose pyrophosphorylase (PMI-GMP)

The nucleotide sequence of a BglII fragment (3188 bp) from the plasmid pKY1 of Rhodospirillum rubrum was determined. A significant similarity was found between the amino acid sequences deduced from the nucleotide sequence of BglII fragment with that of algA, encoding the bifunctional enzyme with both the activities of phosphomannose isomerase and guanosine diphospho-D-mannose pyrophosphorylase of Pseudomonas aeruginosa.

Molecular organization of photochemical reaction complex in chromatophore membrane from Rhodospirillum rubrum as detected by immunochemical and proteolytic analyses

The molecular organization of photochemical reaction (PR) complex in chromatophores from Rhodospirillum rubrum was studied by a combination of proteolytic analysis with proteinase K followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunochemical analysis with rabbit polyclonal antibodies against its five subunits (H, M, L, alpha, and beta). The preparations used for comparison were reaction center complex (RC) (composed of H, M, and L), PR complex, and chromatophores (closed membranous vesicles of polar lipid bilayer having PR complex buried in the membrane). 1. RC was bound with anti-H, anti-M, and anti-L antibodies, whereas PR complex and chromatophores were bound with anti-H and anti-beta antibodies, but not with the other antibodies. 2. With PR complex, H (Mr 31,000 (31K)) was rapidly degraded into two peptides with Mr of 16K and 14.5K (abbreviated as 16K and 14.5K, respectively), M (27K) into 25.5K, and beta (11K) into 10K. Significantly later, the 25.5K of M was degraded into 24K, L (23K) into 19K, and alpha (12K) into 11K. With chromatophores, H and beta were degraded in a manner similar to that with PR complex, whereas M, L, and alpha were not degraded at all. With RC, H, M, and L were rapidly degraded. 3. With RC, the activity for photooxidation of P870 (photochemical activity) was hardly affected till H, M, and L had been degraded into less than 10K, 24K, and 19K, respectively. With PR complex, the absorbance spectrum due to the bacteriochlorophylls of light-harvesting complex-1 composed of alpha and beta (LH1-Bchl) changed in parallel to the degradation of alpha or 10K (a part of beta). 4. Together with the previous results (Ueda et al. (1985) J. Biochem. 98, 1487-1498), the present findings suggest that: 1) RC is directly surrounded by 12 alpha and further by 12 beta; 2) H and beta are mostly and partially exposed, respectively, on the outer surface of the membranous vesicle; 3) a small part of M is exposed on the inner surface of the membranous vesicle.

Effects of NaCl and glycerol on photosynthetic oxygen-evolving activity with thylakoid membranes from halophilic green alga Dunaliella tertiolecta

It is known that the halophilic green alga Dunaliella tertiolecta grows under hypertonic conditions (with NaCl), which induce the intracellular accumulation of high concentrations of glycerol in order to counterbalance the osmotic change. The effects of NaCl and glycerol on the photosynthetic oxygen-evolving activity of thylakoid membranes prepared from D. tertiolecta were investigated in relation to the dissociation of the membranes. It was found that proteins with Mr of 24,000, 17,000, and 13,000 were dissociated from thylakoid membranes of D. tertiolecta by washing with 1 M NaCl, whereas the photosynthetic oxygen-evolving activity was stimulated 2-fold by 0.1-1.5 M NaCl. The antibodies against spinach 24K and 17K proteins did not cross-react with Dunaliella 24K and 17K proteins, respectively. The salt-tolerant feature of the oxygen-evolving activity with Dunaliella thylakoid membranes may be related to the difference of the properties of these two proteins between D. tertiolecta and spinach. When the membranes were washed with 1 M Tris, proteins with Mr of 50,000 and 31,000 were also dissociated in addition to the 24K and 17K proteins described above. The antibody against spinach 33K protein cross-reacted with 31K protein of D. tertiolecta, showing that Dunaliella 31K protein corresponds to spinach 33K protein. When the membranes were treated with a mixture of 1% cholate and 2% deoxycholate, the oxygen-evolving activity was completely depressed, but the depressed activity was significantly restored by organic solvents. Glycerol and dimethylsulfoxide were the most effective for the restoration.(ABSTRACT TRUNCATED AT 250 WORDS)

Intermolecular relations of the photosystem II complex in spinach chloroplasts as detected by immunochemical assay

Polyclonal antibodies were prepared to the subunits of the spinach photosystem II fraction (PS II): p47, p43, p27, p33, p24, and p17. (The protein nomenclature refers to Mr). p47 and p43 are the subunits of reaction center complex, and p27 is light-harvesting chlorophyll protein. p33, p24, and p17 are extractable from PS II with 1 M Tris, and p24 and p17 with 1 M NaCl. With untreated PS II fractions, the antibody to p24 inhibited the photosynthetic oxygen-evolving activity, but not the DCPI-photoreduction activity in the presence of DPC, indicating that p24 played an important role in the former activity. Bindings of the respective antibodies to the PS II treated with sodium dodecyl sulfate were regarded as 100%. To untreated PS II, the bindings were 20-30% for p47, p43, and p27, about 50% for p33, and 70-80% for p24 and p17. To NaCl-washed PS II, the binding to p33 increased by 9%, indicating that p33 was adjacent or bound with p24 or/and p17. To Tris-washed PS II, the binding to p43 increased by 7%, indicating that p43 was adjacent or bound with p33. To PS II treated with 3% of Brij 58, only the binding to p27 increased appreciably. To PS II treated with 1% of octyl glucoside, the binding to p47 was still lower than 50%, whereas those to the other subunits were 74-91%. These values could be a measure of the extents to which the subunits were exposed to the aqueous phase, because of the nature of polyclonal antibodies. These results suggest that in intact PS II, p47, p43, and p27 were in most part buried in the inside, p47 being located at the most central and p27 at the outermost part, whereas p33, p24, and p17 were exposed to the outside by 50-75%.