Dose-response relationship among body mass index, abdominal adiposity and atrial fibrillation in patients undergoing cardiac surgery: a meta-analysis of 35 cohorts.

BACKGROUND: Whether overweight increases the risk of postoperative atrial fibrillation (POAF) is unclear, and whether adiposity independently contributes to POAF has not been comprehensively studied. Thus, we conducted a meta-analysis to clarify the strength and shape of the exposure-effect relationship between adiposity and POAF. METHODS: The PubMed, Cochrane Library, and EMBASE databases were searched for revelant studies (randomized controlled trials (RCTs), cohort studies, and nest-case control studies) reporting data regarding the relationship between adiposity and the risk of POAF. RESULTS: Thirty-five publications involving 33,271 cases/141,442 patients were included. Analysis of categorical variables showed that obesity (RR: 1.39, 95% CI [1.21-1.61]; P < 0.001), but not being underweight (RR: 1.44, 95% CI [0.90-2.30]; P = 0.13) or being overweight (RR: 1.03, 95% CI [0.95-1.11]; P = 0.48) was associated with an increased risk of POAF. In the exposure-effect analysis (BMI) was 1.09 (95% CI [1.05-1.12]; P < 0.001) for the risk of POAF. There was a significant linear relationship between BMI and POAF (Pnonlinearity = 0.44); the curve was flat and began to rise steeply at a BMI of approximately 30. Notably, BMI levels below 30 (overweight) were not associated with a higher risk of POAF. Additionally, waist obesity or visceral adiposity index was associated with the risk of POAF. CONCLUSION: Based on the current evidence, our findings showed that high body mass index or abdominal adiposity was independently associated with an increased risk of POAF, while underweight or overweight might not significantly increase the POAF risk.

Effect of down-regulated miR-15b-5p expression on arrhythmia and myocardial apoptosis after myocardial ischemia reperfusion injury in mice.

In this study, the regulation of miR-15b-5p on myocardial ischemia reperfusion (I/R) injury-induced arrhythmia and myocardial apoptosis was investigated in mice. We observed the change in miR-15b-5p expression after mice suffered from myocardial I/R injury and the change in myocardial injury, infarct size, apoptosis, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), superoxide dismutase (SOD) and malondialdehyde (MDA) after down-regulation of miR-15b-5p expression. The negative regulation of miR-15b-5p to KCNJ2 as well as whether cardioprotective effect formed by miR-15b-5p down-regulation relied on the increase of KNCJ2 expression were measured by dual-luciferase reporter assay system. miR-15b-5p expression increased and KCNJ2 mRNA and protein expressions decreased after myocardial ischemia reperfusion (all P < 0.05). miR-15b-5p negatively regulated KCNJ2 in a targeted way. Down-regulating miR-15b-5p expression or increasing KCNJ2 expression significantly decreased the incidence of arrhythmia, infarct size and apoptosis after myocardial I/R and lowered MDA content in the myocardial tissue as well as IL-6 and TNF-α content in the blood (all P < 0.05). KCNJ2 gene knockout reversed the above cardioprotective effect formed by miR-15b-5p down-regulation (P < 0.05). Down-regulating miR-15b-5p expression or up-regulating KCNJ2 expression improves arrhythmia after mice suffered from myocardial I/R injury and inhibits myocardial apoptosis.

[Rs17042171 at chromosome 4q25 is associated with atrial fibrillation in the Chinese Han population from the central plains].

OBJECTIVE: To determine the correlations of single nucleotide polymorphisms (SNPs) with atrial fibrillation (AF) in the Chinese Han population from the central plains.
 Methods: A total of 168 hospitalized patients, including 56 AF and 112 controls, were recruited in this case-control study. The clinical data were obtained from the medical records. All 5 SNPs, rs337711 in KCNN2, rs11264280 near KCNN3, rs17042171 near PITX2, rs6771157 and rs6795970 in SCN10A, were genotyped using amplification refractory mutation system-polymerase chain reaction or direct sequencing. The χ2 test was used to compare categorical variables and preliminarily examine correlations between the genotype frequencies and AF. Subsequently, a logistic regression model was constructed to determine the associations between the SNPs and AF based on the above screened results. Odds ratios (ORs) and 95% confidence interval (CI) were calculated to assess the strength of the correlations. Moreover, we downloaded the genotype data from the HapMap Project for linkage disequilibrium analysis of rs17042171.
 Results: AF patients were likely to be of older age and longer left atrial diameter and had more coronary artery disease and higher hypertension compared with the control group (P<0.05). Among the 5 SNPs, the frequency distribution of genotype AA for rs17042171 was significantly different between the AF and control groups (P<0.05). After adjusting for several covariates, there was still a high risk ratio in patients with the AA genotype compared with the AC+CC genotype (OR: 5.591, 95%CI 2.176 to 14.365, P-B<0.008). Similarly, stratification analysis on the AA genotype demonstrated significant differences between rs17042171 and persistent AF. However, there were not significant correlations between AF and the control groups for the other 4 SNPs (P<0.05).
 Conclusion: Rs17042171, near PITX2 on chromosome 4q25, is associated with AF susceptibility in the Chinese Han population from the central plains, suggesting that this SNP can provide a new strategy for clinical diagnosis in AF patients.

Long-term follow up of interventional therapy of secundum atrial septal defect.

BACKGROUND: The percutaneous transcatheter closure of secundum atrial septal defect (ASD) is increasingly a widespread alternative to surgical closure. The aim of this study was to assess long-term results of percutaneous closure of secundum-type atrial septal defect (ASDII). METHODS: Between January 2001 and December 2005, 61 patients underwent a successful percutaneous closure of ASDII; including 25 male and 36 female. All were included in the patient study and were followed up to monitor by electrocardiogram and echocardiography, at intervals of 3 days, 3 months, 6 months, 1 year, 2 years, and 5 years after operation. RESULTS: Three days after percutaneous transcatheter septal closure (PTSC), the right atrium diameter, right ventricular end-diastolic left-right diameter and right ventricular end-diastolic volume (RVEDV) decreased significantly (P < 0.05). Right ventricular end-diastolic anteroposterior diameter (RVEDD), right ventricular end-systolic volume (RVESV) and right ventricular ejection fraction (RVEF) also decreased (P < 0.01). During the period from 3 to 6 months, the size of the right atrium and right ventricle returned to normal range. Three days after PTSC, the left ventricular end-diastolic diameter (LVEDD), left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVESV), left ventricular-systolic volume (LVSV) and left ventricular ejection fraction (LVEF) were significantly increased (P < 0.05). At 1 year, the size of the left atrium, left ventricle and left cardiac function returned to normal range (P < 0.01). There were no deaths or significant complications during the study. At five year follow-up, all defects were completely closed and remained closed thereafter. CONCLUSION: Transcatheter closure of ASDII effectively eliminated the abnormal shunt and, subsequently improved the dimensions of each chamber and cardiac function.