Hung-Yu Chang

Myostatin expression in ventricular myocardium in a rat model of volume-overload heart failure

Backgroundu2002 Mechanical stress increases myocardial myostatin expression. However, the expression of myostatin in chronic heart failure resulting from volume‐overload and after treatment with β‐blockers is little known. The authors hypothesize that myostatin plays a role in the failing myocardium because of volume‐overload.

TSOC-HFrEF Registry: A Registry of Hospitalized Patients with Decompensated Systolic Heart Failure: Description of Population and Management

INTRODUCTIONnHeart failure (HF) is a medical condition with a rapidly increasing incidence both in Taiwan and worldwide. The objective of the TSOC-HFrEF registry was to assess epidemiology, etiology, clinical management, and outcomes in a large sample of hospitalized patients presenting with acute decompensated systolic HF.nnnMETHODSnThe TSOC-HFrEF registry was a prospective, multicenter, observational survey of patients presenting to 21 medical centers or teaching hospitals in Taiwan. Hospitalized patients with either acute new-onset HF or acute decompensation of chronic HFrEF were enrolled. Data including demographic characteristics, medical history, primary etiology of HF, precipitating factors for HF hospitalization, presenting symptoms and signs, diagnostic and treatment procedures, in-hospital mortality, length of stay, and discharge medications, were collected and analyzed.nnnRESULTSnA total of 1509 patients were enrolled into the registry by the end of October 2014, with a mean age of 64 years (72% were male). Ischemic cardiomyopathy and dilated cardiomyopathy were diagnosed in 44% and 33% of patients, respectively. Coronary artery disease, hypertension, diabetes, and chronic renal insufficiency were the common comorbid conditions. Acute coronary syndrome, non-compliant to treatment, and concurrent infection were the major precipitating factors for acute decompensation. The median length of hospital stay was 8 days, and the in-hospital mortality rate was 2.4%. At discharge, 62% of patients were prescribed either angiotensin-converting enzyme-inhibitors or angiotensin receptor blockers, 60% were prescribed beta-blockers, and 49% were prescribed mineralocorticoid receptor antagonists.nnnCONCLUSIONSnThe TSOC-HFrEF registry provided important insights into the current clinical characteristics and management of hospitalized decompensated systolic HF patients in Taiwan. One important observation was that adherence to guideline-directed medical therapy was suboptimal.

The utilization of twelve-lead electrocardiography for predicting sudden cardiac death after heart transplantation

BACKGROUNDnSudden cardiac death (SCD) occurs commonly after heart transplantation (HTX). The utilization of surface electrocardiography (ECG) to assess post-HTX SCD has not been investigated thoroughly. This study aimed to investigate the specific changes in surface ECG in HTX patients with SCD.nnnMETHODSnA total of 227 HTX patients (age 48 ± 14 y/o, mean donor age 34 ± 14 y/o, 173 males) were followed up regularly at the outpatient clinic. Twelve-lead ECGs were recorded during 1-2 monthly visits. Serial ECG parameters and relevant clinical data were collected and analyzed.nnnRESULTSnDuring the follow-up period of 96 ± 51 months, SCD occurred in 28 (12.3%) patients. The baseline ECG parameters were comparable between patients with and without SCD. Important ECG trends of rising rest heart rates and prolongation of corrected QT (QTc) and JT (JTc) intervals were observed prior to development of SCD. After adjustment for other clinical variables, the independent predictors for SCD were older donor age (p = 0.014, OR 1.05, 95% CI 1.01-1.09), faster heart rate (p = 0.006, OR 1.06, 95% CI 1.02-1.1) and longer JTc interval (p = 0.015, OR 1.03, 95% CI 1.01-1.06). SCD occurred in 71.4% patients presenting with all three risk predictors.nnnCONCLUSIONSnBesides older donor age, important ECG signs, including prolongation of the JTc interval and increased heart rate during post HTX follow up, could predict SCD.

The autonomic neural mechanism of right ventricular outflow tract tachycardia

BACKGROUNDnVentricular tachycardia (VT) and ventricular premature complexes (VPCs) originating from the right ventricular outflow tract (RVOT) are generally considered as benign arrhythmias, with ECG morphology showing LBBB pattern and inferior axis. Pathogenic mechanisms in the genesis of RVOT VT/VPC remain largely unknown. We aimed to investigate the neural mechanism in RVOT ventricular arrhythmias in canine model.nnnMETHODSnTwelve mongrel dogs (13.7u202f±u202f1.3u202fkg, 5 male dogs) were studied through midline thoracotomies. High-frequency stimulation (HFS) was applied to the proximal pulmonary artery (PA) to induce RVOT VT/VPC. An EnSite Array and a mapping catheter were used for electroanatomical mapping. The RVOT and PA were surgically excised for immunohistochemistry studies, including tyrosine hydroxylase (TH) stain for sympathetic nerves and choline acetyltransferase (ChAT) stain for parasympathetic nerves.nnnRESULTSnIn nine (75%) out of twelve dogs, HFS of the proximal PA induced RVOT VT/VPC. The density of TH-positive nerves was significantly higher than that of ChAT-positive nerves (6803u202f±u202f700 vs. 670u202f±u202f252u202fμm2/mm2, pu202f<u202f0.001). Furthermore, the density of TH-positive nerves was also significantly higher in the VT/VPC origin sites than that in the non-origin sites (18,044u202f±u202f2866 vs. 5554u202f±u202f565u202fμm2/mm2, pu202f=u202f0.002). Catheter ablation of the proximal PA eliminated the inducibility of RVOT VT/VPC successfully.nnnCONCLUSIONSnHFS of the proximal PA could induce RVOT VT/VPC. The sympathetic nerves were densely innervated to the origin of RVOT VT/VPC, indicating the critical role of sympathetic hyperactivity in the initiation and perpetuation of RVOT VT/VPC.

Gap between guidelines and clinical practice in heart failure with reduced ejection fraction: Results from TSOC-HFrEF registry

Background Heart failure (HF) is a global health problem. Guidelines for the management of HF have been established in Western countries and in Taiwan. However, data from the Taiwan Society of Cardiology‐Heart Failure with reduced Ejection Fraction (TSOC‐HFrEF) registry showed suboptimal prescription of guideline‐recommended medications. We aimed to analyze the reason of non‐prescription and clinical outcomes as a result of under‐prescription of medications. Methods A total of 1509 patients hospitalized for acute HFrEF were recruited in 21 hospitals in Taiwan by the end of October 2014. Prescribed guideline‐recommended medications and other relevant clinical parameters were collected and analyzed at discharge and 1 year after index hospitalization. Results At discharge, 62% of patients were prescribed with either angiotensin‐converting enzyme‐inhibitors (ACEI) or angiotensin receptor blockers (ARB); 60% were prescribed with beta‐blockers and 49% were prescribed with mineralocorticoid receptor antagonists (MRA). The proportions of patients at ≥50% of the target dose for ACEI/ARB, beta‐blockers and MRA were 24.4%, 20.6%, 86.2%, respectively. At 1‐year follow‐up, dosages of ACEI/ARB and MRA were up‐titrated in about one‐fourth patients, and dosages of beta‐blocker were up‐titrated in about 40% patients. One‐year mortality rate was lowest in patients who received at least 2 classes of guideline‐recommended medications with ≥50% of the target dose, and highest in those who received 0 or 1 class of medications. Conclusion The TSOC‐HFrEF registry demonstrated the under‐prescription of guideline‐recommended medications and reluctance of physicians to up‐titrate medications to target dose. Action plan needs be formulated in order to improve physicians adherence to HF guidelines.

When Atrial Fibrillation Co-Exists with Coronary Artery Disease in Patients with Prior Coronary Intervention - Does Ablation Benefit?

BACKGROUNDnAtrial fibrillation (AF) can be associated with an increased risk of developing coronary artery disease (CAD) due to mechanisms of inflammation, endothelial dysfunction and adverse atrial remodelling. It is unclear if adverse coronary events can be further reduced after successful catheter ablation of AF. We hypothesise that AF ablation and sinus maintenance could reduce future adverse cardiac events in patients with underlying CAD.nnnMETHODSnA total of 310 patients with drug-refractory paroxysmal AF and prior history of percutaneous coronary intervention (PCI) for underlying CAD were recruited in the retrospective case control study. Of these, 155 patients underwent AF ablation (the Ablation Group), while 155 patients received medical treatment (the Medical Group). All patients were followed up for major adverse cardiac events, including acute coronary syndrome requiring hospitalisation, stroke, pulmonary embolism and mortality.nnnRESULTSnThe clinical characteristics were comparable between the two groups, except for higher antiarrhythmic drug use in the Medical Group. During a follow-up duration of 61±32 months, all-cause mortality (8.4% vs. 1.3%, p=0.004) and the overall major adverse events (47.7% vs. 12.3%, p<0.001) were significantly higher in the Medical Group than the Ablation Group. There were also more instances of stroke (10.3% vs. 3.2%, p=0.013) and acute coronary syndrome requiring hospitalisation (29% vs. 7.1%, p<0.001) in the Medical Group than the Ablation Group. Multivariate analysis confirmed that non-ablation was an independent risk factor for major adverse events (p<0.001, HR 3.4, 95% confidence interval 1.9-5.9).nnnCONCLUSIONnIn PAF patients with established CAD who underwent PCI, catheter ablation could lead to fewer major adverse cardiac events compared to medical therapy.