Obstructive sleep apnea and electrocardiographic P-wave morphology.

INTRODUCTION: Obstructive sleep apnea (OSA) is a highly prevalent sleep disorder with important cardiovascular implications. Left atrial abnormality can be identified by electrocardiographic P-wave morphology and is considered an important risk for atrial fibrillation (AF) and stroke, both of which have been associated with OSA. We hypothesized that severity of OSA would be associated with more abnormal electrocardiographic P-wave morphology as indicated by P-wave terminal force in V1 (PTFV1 ) and P-wave area in V1 (PWAV1 ). METHODS: Patients who underwent clinically indicated polysomnography and had 12-lead ECG were identified through medical record review. Logistic regression was used to determine the associations between the measures of OSA severity (apnea hypopnea index [AHI] and mean nocturnal oxygen [O2 ] saturation) and abnormal PTFV1 and PWAV1 (defined by >75% percentile value of the studied cohort) adjusting for age, sex, body mass index, and hypertension. RESULTS: A total of 261 patients (mean age: 57 years old, male: 52%) were included in the study. Multivariate analysis showed that AHI was associated with abnormal PTFV1 (>7,280 µV ms) and PWAV1 (>1,000 µV ms; OR: 1.5; 95% CI [1.1, 2.0], p = 0.008; OR: 1.5 [1.1, 2.1], p = 0.005 per 1 SD increase in AHI, respectively). Mean O2 saturation was associated with abnormal PWAV1 (OR: 0.72 [0.54, 0.98], p = 0.03). Results remained unchanged after excluding patients taking AV nodal blocking agents. CONCLUSION: In a sleep clinic cohort, there was significant association between OSA severity and ECG-defined left atrial abnormality.

Atrial Fibrillation and Objective Sleep Quality by Slow Wave Sleep.

BACKGROUND: Self-reported poor sleep quality has been suggested in patients with AF. Slow wave sleep (SWS) is considered the most restorative sleep stage and represents an important objective measure of sleep quality. The aim of this study was to compare quantity of SWS between patients with and without AF. METHODS AND RESULTS: We included patients with and without a documented history of AF by reviewing clinically indicated polysomnography data from a single sleep center. Patients on medications with potential influence on sleep architecture were excluded. Logistic regression was performed to determine the association between AF and SWS time (low vs. high) adjusting for age, gender, body mass index, and sleep apnea. In a 2:1 case-control set-up, a total of 205 subjects (139 with AF, 66 without AF) were included. Mean age was 62 (SD: 14.3) years and 59% were men. Patients with AF had lower SWS time (11.1 vs. 16.6 min, p=0.02). In multivariable analysis, prevalent AF was associated with low SWS independent of sleep apnea and other potential confounders (OR 2.5 [1.3, 5.0], p=0.006). Limiting the analysis to patients whose total sleep time was greater than 4 hours (by excluding N=31) resulted in more robust results (OR 3.9 [1.7, 9.7]. p=0.002). CONCLUSION: AF is associated with more impaired sleep quality as indicated by lower quantity of SWS. More studies are needed to explore the mechanistic interactions between AF and sleep.

Safety of transradial cardiac catheterization in patients with end-stage liver disease.

BACKGROUND: Transradial access may be advantageous for patients with end-stage liver disease (ESLD) who need to undergo left heart catheterization (LHC). We aimed to assess the safety of transradial cardiac catheterization in patients listed for orthotopic liver transplantation. METHODS: This is a retrospective analysis of consecutive adult patients with the diagnosis of ESLD, who underwent LHC via transradial access as part of a pre-operative liver transplantation evaluation. All the patients also underwent right heart catheterization (RHC) via brachial or femoral vein. The primary outcome measure was procedure-related major bleeding. Secondary outcomes included access site minor bleeding, in-hospital mortality, radial access failure, and acute kidney injury. RESULTS: A total of 82 consecutive patients with ESLD, who underwent LHC via transradial access, were enrolled in the study. All patients also underwent RHC (n = 45 via brachial and n = 37 via femoral vein). The median age was 59 (54, 67) years old, and 58% were male. History of coronary artery disease or heart failure was present in 17% of patients. The median MELD score was 19 (13, 24.5), baseline hemoglobin was 10.5 mg/dL (9.4, 11.8), INR was 1.4 (1.2, 1.8) and platelets were 74,000 (53,000, 117,000)/mm(3) . The most common etiology of liver failure was viral hepatitis (51%), followed by alcoholic cirrhosis (24%) and non-alcoholic steatohepatitis (21%). Angiographically significant coronary artery disease was present in 17 (21%) patients. Major bleeding and acute kidney injury each occurred in two patients (2.4%). There were no instances of vascular complications. There were no deaths attributable to complications from cardiac catheterization. CONCLUSION: Upper extremity right and left heart catheterization appears to be a safe method to evaluate coronary anatomy and hemodynamics in a severely ill population of patients with ESLD awaiting transplant.

The human protein PRR14 tethers heterochromatin to the nuclear lamina during interphase and mitotic exit.

The nuclear lamina is a protein meshwork that lies under the inner nuclear membrane of metazoan cells. One function of the nuclear lamina is to organize heterochromatin at the inner nuclear periphery. However, very little is known about how heterochromatin attaches to the nuclear lamina and how such attachments are restored at mitotic exit. Here, we show that a previously unstudied human protein, PRR14, functions to tether heterochromatin to the nuclear periphery during interphase, through associations with heterochromatin protein 1 (HP1) and the nuclear lamina. During early mitosis, PRR14 is released from the nuclear lamina and chromatin and remains soluble. Strikingly, at the onset of anaphase, PRR14 is incorporated rapidly into chromatin through HP1 binding. Finally, in telophase, PRR14 relocalizes to the reforming nuclear lamina. This stepwise reassembly of PRR14 suggests a function in the selection of HP1-bound heterochromatin for reattachment to the nuclear lamina as cells exit mitosis.