Cardiorespiratory Phase-Coupling Is Reduced in Patients with Obstructive Sleep Apnea

Cardiac and respiratory rhythms reveal transient phases of phase-locking which were proposed to be an important aspect of cardiorespiratory interaction. The aim of this study was to quantify cardio-respiratory phase-locking in obstructive sleep apnea (OSA). We investigated overnight polysomnography data of 248 subjects with suspected OSA. Cardiorespiratory phase-coupling was computed from the R-R intervals of body surface ECG and respiratory rate, calculated from abdominal and thoracic sensors, using Hilbert transform. A significant reduction in phase-coupling was observed in patients with severe OSA compared to patients with no or mild OSA. Cardiorespiratory phase-coupling was also associated with sleep stages and was significantly reduced during rapid-eye-movement (REM) sleep compared to slow-wave (SW) sleep. There was, however, no effect of age and BMI on phase coupling. Our study suggests that the assessment of cardiorespiratory phase coupling may be used as an ECG based screening tool for determining the severity of OSA

Predictors of early-stage left ventricular dysfunction in type 2 diabetes: results of DYDA study

Better knowledge of prevalence and early-stage determinants of subclinical left ventricular dysfunction (LVD) in type 2 diabetes would be useful to design prevention strategies. The objective of the LVD in Diabetes (DYDA) study was to assess these points in patients without established cardiac disease. METHOD: Baseline clinical, ECG, laboratory and echocardiographic data from 751 patients (61 ± 7 years, 59% hypertensive) recruited by 37 Italian diabetes clinics were analysed. Clinical history, life habits, laboratory data (NT-proBNP, HsCRP, HbA1c, serum glucose, lipids and creatinine, liver enzymes, microalbuminuria, glomerular filtrate) and data on microvascular complications and drug therapy were collected. RESULTS: LVD was present in 59.9% of patients. Age (OR 1.05, 95% CI [1.02-1.07]), HbA1c (OR 1.27, 95% CI [1.09-1.49]), triglycerides (OR 1.003, 95% CI [1.001-1.006]), treatment with metformin (OR 1.62, 95% CI [1.09-2.40]) and doxazosine (OR 2.48, 95% CI [1.10-5.55]) were independent predictors of LVD. Glitazones were associated with reduced risk of diastolic dysfunction (OR 0.44, 95% CI [0.22-0.87]) whereas waist circumference and metformin were adversely associated with systolic dysfunction (OR 1.02, 95% CI [1.01-1.04] and 1.57, 95% CI [1.01-2.43], respectively). CONCLUSION: In asymptomatic and fairly controlled diabetic patients, age, worse HbA1c, traits of insulin resistance, such as visceral adiposity and triglycerides or treatment with metformin, and use of doxazosin indicate greater risk of LVD. Glitazones, at this stage, seem to be associated with better diastolic performance

Formation of C-C bonds via iridium-catalyzed hydrogenation and transfer hydrogenation

The formation of C–C bonds via catalytic hydrogenation and transfer hydrogenation enables carbonyl and imine addition in the absence of stoichiometric organometallic reagents. In this review, iridium-catalyzed C–C bond-forming hydrogenations and transfer hydrogenations are surveyed. These processes encompass selective, atom-economic methods for the vinylation and allylation of carbonyl compounds and imines. Notably, under transfer hydrogenation conditions, alcohol dehydrogenation drives reductive generation of organoiridium nucleophiles, enabling carbonyl addition from the aldehyde or alcohol oxidation level. In the latter case, hydrogen exchange between alcohols and π-unsaturated reactants generates electrophile–nucleophile pairs en route to products of hydro-hydroxyalkylation, representing a direct method for the functionalization of carbinol C–H bonds