Three third-order quadrature oscillators are proposed. Outputs of two sinusoids with 90 phase difference are available in each quadrature oscillator circuit. The oscillation condition and oscillation frequency of each proposed quadrature oscillator are orthogonal controllable. All proposed circuits employ only grounded capacitors. The use of only grounded capacitors is ideal for integration. Experimental results are included to confirm the theoretical analysis.
Aims Arrhythmogenic cardiomyopathy (AC) shows large heterogeneity in its clinical, genetic, and pathological presentation. This study aims to provide a comprehensive atlas of end-stage AC and illustrate the relationships among clinical characteristics, genotype, and pathological profiles of patients with this disease. Methods and results We collected 60 explanted AC hearts and performed standard pathology examinations. The clinical characteristics of patients, their genotype and cardiac magnetic resonance imaging findings were assessed along with pathological characteristics. Masson staining of six representative sections of each heart were performed. Digital pathology combined with image segmentation was developed to calculate distribution of myocardium, fibrosis, and adipose tissue. An unsupervised clustering based on fibrofatty distribution containing four subtypes was constructed. Patients in Cluster 1 mainly carried desmosomal mutations (except for desmoplakin) and were subjected to transplantation at early age; this group was consistent with classical ‘desmosomal cardiomyopathy’. Cluster 2 mostly had non-desmosomal mutations and showed regional fibrofatty replacement in right ventricle. Patients in Cluster 3 showed parallel progression, and included patients with desmoplakin mutations. Cluster 4 is typical left-dominant AC, although the genetic background of these patients is not yet clear. Multivariate regression analysis revealed precordial QRS voltage as an independent indicator of the residual myocardium of right ventricle, which was validated in predicting death and transplant events in the validation cohort (n = 92). Conclusion This study provides a novel classification of AC with distinct genetic backgrounds indicating different potential pathogenesis. Cluster 1 is distinct in genotype and clinicopathology and can be defined as ‘desmosomal cardiomyopathy’. Precordial QRS amplitude is an independent indicator reflecting the right ventricular remodelling, which may be able to predict transplant/death events for AC patients.
BackgroundVeno-arterial extracorporeal membrane oxygenation (VA-ECMO) is widely used in postcardiotomy cardiac shock (PCS). The factors that affect mortality in patients who receive ECMO for PCS remain unclear. In this study, we analyzed the outcomes, predictive factors and complications of ECMO use for PCS.MethodsA total of 152 adult subjects who received VA-ECMO for PCS in Fuwai Hospital were consecutively included. We retrospectively collected the baseline characteristics, outcomes and complications. Baseline characteristics were compared between survivors with non-survivors, and logistic regression was performed to identify predictive factors for in-hospital mortality.ResultsThe mean age of the subjects was 49.5 ± 14.1 years, with a male dominancy of 73.7%. The main surgical procedures were heart transplantation (32.2%), coronary artery bypass graft (17%) and valvular surgery (11.8%). Intra-aortic balloon pumping (IABP) was initiated concurrently with ECMO in 32.2% subjects and sequentially in 18.4% subjects. The ECMO weaning rate was 56.6%, and the in-hospital mortality was 52.0%. When compared with non-survivors, survivors had less hypertension (15.1% vs. 35.4%, p = 0.004), secondary thoracotomy before ECMO initiation (19.2% vs. 39.2%, p = 0.007), pre-ECMO cardiac arrest/ventricular fibrillation (11.0% vs. 34.2%, p = 0.001), bedside implantation of ECMO (11.0% vs. 41.8%, p < 0.001), and more transplant procedure (45.2% vs. 20.3%, p = 0.001), concurrent IABP initiation with ECMO (41.1% vs. 24.1%, p = 0.025). Multivariate logistic regression indicated concurrent IABP initiation with ECMO was the only independent protective factor for in-hospital mortality (OR = 0.375, p = 0.041, 95% CI 0.146–0.963). Concurrent IABP initiation with ECMO had less need for continuous renal replacement therapy (30.6% vs. 49.3%, p = 0.039) and less neurological complications (8.2% vs. 22.7%, p = 0.035), but more thrombosis complications (18.4% vs. 2.7%, p = 0.007).ConclusionConcurrent initiation of IABP with ECMO provides better short-term survival for PCS, with reduced peripheral perfusion complications.
The aim of this study is to report the combined application of extracorporeal membrane oxygenation (ECMO) with intra‐aortic balloon pumping (IABP) in postcardiotomy cardiac shock (PCS). A total of 60 consecutive patients who received both ECMO and IABP (concomitantly 24 hours) for PCS from February 2006 to March 2017 at Fuwai Hospital were included in our study. Clinical characteristics of the patients were collected retrospectively and compared between survivors and non‐survivors. Logistic regression analysis was used as predictors for survival to discharge. The study cohort had a mean age of 51.4±12.7 years with 75% males. ECMO was implanted intra‐operatively in 38 (63%) patients and post‐operatively in 22 (37%) patients. ECMO was implanted concurrently with IABP in 38 (63%) patients. Heart transplantation (38%) and coronary artery bypass graft (33%) were the main surgical procedures. ECMO was weaned successfully in 48% patients, and the rate of survival to discharge was 43%. Survivors showed less bedside ECMO implantation (12% vs. 41%, P=0.012) and more concurrent implantation of ECMO with IABP (81% vs. 50%, P=0.014). Concurrent implantation of IABP with ECMO (OR=0.177, P=0.015, 95% CI: 0.044‐0.718) was an independent predictor of survival to discharge. As for complications, the rate of renal failure (59% vs. 15%, P=0.001) and multiple organ dysfunction syndrome (29% vs. 0, P=0.003) was higher in patients who failed to survive to discharge. Patients who had heart transplantation had a better long‐term survival than others (P=0.0358). In summary, concurrent implantation of ECMO with IABP provides better short‐term outcome for PCS and combined application of ECMO with IABP for PCS after heart transplantation had a favorable long‐term outcome.
Background and objective Heart failure (HF) is a global health issue, and coronary artery bypass graft (CABG) is one of the most effective surgical treatments for HF with coronary artery disease. Unfortunately, the incidence of postoperative acute kidney injury (AKI) is high in HF patients following CABG, and there are few tools to predict AKI after CABG surgery for such patients. The aim of this study is to establish a nomogram to predict the incidence of AKI after CABG in patients with impaired left ventricular ejection fraction (LVEF). Methods From 2012 to 2017, Clinical information of 1208 consecutive patients who had LVEF< 50% and underwent isolated CABG was collected to establish a derivation cohort. A novel nomogram was developed using the logistic regression model to predict postoperative AKI among these patients. According to the same inclusion criteria and the same period, we extracted the data of patients from 6 other large cardiac centers in China (n = 540) from the China Heart Failure Surgery Registry (China-HFSR) database for external validation of the new model. The nomogram was compared with 3 other available models predicting renal failure after cardiac surgery in terms of calibration, discrimination and net benefit. Results In the derivation cohort (n = 1208), 90 (7.45%) patients were diagnosed with postoperative AKI. The nomogram included 7 independent risk factors: female, increased preoperative creatinine(> 2 mg/dL), LVEF< 35%, previous myocardial infarction (MI), hypertension, cardiopulmonary bypass(CPB) used and perioperative blood transfusion. The area under the receiver operating characteristic curve (AUC) was 0.738, higher than the other 3 models. By comparing calibration curves and decision curve analyses (DCA) with other models, the novel nomogram showed better calibration and greater net benefit. Among the 540 patients in the validation cohort, 104 (19.3%) had postoperative AKI, and the novel nomogram performed better with respect to calibration, discrimination and net benefit. Conclusions The novel nomogram is a reliable model to predict postoperative AKI following isolated CABG for patients with impaired LVEF.
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