Supraventricular tachyarrhythmias in patients with a persistent left superior vena cava.

Aims: A persistent left superior vena cava (PLSVC) is the most common thoracic venous anomaly. This venous anomaly can impact the evaluation and treatment of supraventricular tachyarrhythmia (SVA). The aim of this study was to assess the proportion and characteristics of PLSVC in adult SVA patients. Methods and results: From July 2002 to July 2012, clinical and procedural data from databases of 10 cardiac electrophysiology laboratories in the Yeungnam region of the Republic of Korea were reviewed. Of 6662 adult SVA patients who underwent an EP study or catheter ablation of SVA during the 10-year study period, 18 patients had PLSVC (mean age 47.6 ± 14.8 years, 10 men). The proportion of PLSVC in adult SVA patients was 0.27% (18/6662). SVA type and procedural outcomes of radiofrequency (RF) catheter ablation in these patients were investigated and the results were as follows: successful slow pathway modification in six of seven patients with atrioventricular nodal reentrant tachycardia (AVNRT), successful ablation of accessory pathway in three of four patients with atrioventricular reentrant tachycardia, and successful ablation of atrial tachycardia (cavotricuspid isthmus-dependent in two, septal macroreentry in one, focal from the PLSVC in one) in three of four patients. In one patient with junctional tachycardia, catheter ablation failed. In two patients with atrial fibrillation, catheter ablation was successful. Conclusion: Among adult SVA patients who underwent an EP study or RF catheter ablation during the 10-year study period, 0.27% had PLSVC. The most common type of SVA was AVNRT. The success rate of catheter ablation was 82% in SVA patients with PLSVC. There were no procedure-related complications.

The Melatonin Signaling Pathway in a Long-Term Memory In Vitro Study.

The activation of cyclic adenosine monophosphate (cAMP) response element-binding protein (CREB) via phosphorylation in the hippocampus is an important signaling mechanism for enhancing memory processing. Although melatonin is known to increase CREB expression in various animal models, the signaling mechanism between melatonin and CREB has been unknown in vitro. Thus, we confirmed the signaling pathway between the melatonin receptor 1 (MT1) and CREB using melatonin in HT-22 cells. Melatonin increased MT1 and gradually induced signals associated with long-term memory processing through phosphorylation of Raf, ERK, p90RSK, CREB, and BDNF expression. We also confirmed that the calcium, JNK, and AKT pathways were not involved in this signaling pathway by melatonin in HT-22 cells. Furthermore, we investigated whether melatonin regulated the expressions of CREB-BDNF associated with long-term memory processing in aged HT-22 cells. In conclusion, melatonin mediated the MT1-ERK-p90RSK-CREB-BDNF signaling pathway in the in vitro long-term memory processing model and increased the levels of p-CREB and BDNF expression in melatonin-treated cells compared to untreated HT-22 cells in the cellular aged state. Therefore, this paper suggests that melatonin induces CREB signaling pathways associated with long-term memory processing in vitro.

Extension of catheter ablation and outcome for ventricular tachycardia or premature ventricular contractions from the right ventricular outflow tract.

Objective We aimed to determine whether the extension of ablation could influence the ablation outcome for ventricular tachycardia (VT)/premature ventricular contractions (PVCs) from the right ventricular outflow tract (RVOT). Methods and results The radiofrequency catheter ablation results of 33 VT/6 frequent PVCs from the RVOT were analysed. The ablation extension was divided into 3 categories from the final successful ablation point with the earliest activation: (I) focal ablation (15 cases); ablation at 1 or 2 points; (II) focal with extended ablation (12 cases); focal and surrounding area ablation (maximum ≤1 cm) after elimination of clinical VT/PVCs; and (III) broad ablation (12 cases); continued broad ablation (maximum >1 cm) after elimination of clinical VT/PVCs. Acute termination was defined as the complete elimination and non-inducibility of clinical VT/PVCs during the procedure. For the mean follow-up of 12.8 months, the recurrence rate was not significantly different among the groups (P = 0.49). The mean procedure time was longer in group II, but ablation times and complication rates were not different among the groups. When acute termination was achieved, the overall recurrence rate was 7.6%. However, when confirming absence of the clinical VT/PVCs using 24-hour Holter monitoring immediately after the procedure, the recurrence rate was 2.7%. Conclusions Ablation extension did not affect ablation outcome of VT/PVCs from the RVOT. Confirmation of absence of clinical VT/PVCs using 24-hour Holter monitoring immediately after the procedure could guarantee long-term success.

Induction of Inflammation In Vivo by Electrocardiogram Sensor Operation Using Wireless Power Transmission.

Prolonged monitoring by cardiac electrocardiogram (ECG) sensors is useful for patients with emergency heart conditions. However, implant monitoring systems are limited by lack of tissue biocompatibility. Here, we developed an implantable ECG sensor for real-time monitoring of ventricular fibrillation and evaluated its biocompatibility using an animal model. The implantable sensor comprised transplant sensors with two electrodes, a wireless power transmission system, and a monitoring system. The sensor was inserted into the subcutaneous tissue of the abdominal area and operated for 1 h/day for 5 days using a wireless power system. Importantly, the sensor was encapsulated by subcutaneous tissue and induced angiogenesis, inflammation, and phagocytosis. In addition, we observed that the levels of inflammation-related markers increased with wireless-powered transmission via the ECG sensor; in particular, levels of the Th-1 cytokine interleukin-12 were significantly increased. The results showed that induced tissue damage was associated with the use of wireless-powered sensors. We also investigated research strategies for the prevention of adverse effects caused by lack of tissue biocompatibility of a wireless-powered ECG monitoring system and provided information on the clinical applications of inflammatory reactions in implant treatment using the wireless-powered transmission system.

Usefulness of Frequency Domain Optical Coherence Tomography Compared with Intravascular Ultrasound as a Guidance for Percutaneous Coronary Intervention.

OBJECTIVES: To compare outcomes and rates of optimal stent placement between optical coherence tomography (OCT) and intravascular ultrasound (IVUS) guided percutaneous coronary intervention (PCI). BACKGROUND: Unlike IVUS-guided PCI, rates of clinical outcomes and optimal stent placement have not been well characterized for OCT-guided PCI. METHODS: The study enrolled 290 patients who underwent implantation of a second generation drug eluting stent under OCT (122 patients) or IVUS (168 patients) guidance. The two groups were compared after adjusting for baseline differences using 1:1 propensity score matching (PSM) (114 patients in each group). Optimal stent placement was defined as achieving an adequate lumen (optimal minimum stent area [MSA > 4.85 mm(2) for OCT, >5 mm(2) for IVUS] or a final MSA ≥ 90% of the distal reference lumen area, without edge dissection, incomplete stent apposition, or tissue prolapse), or otherwise performing additional interventions to address suboptimal post-stenting OCT or IVUS findings. The primary endpoint was one-year cumulative incidence of major adverse cardiac events (MACE; cardiac death, myocardial infarction and target lesion revascularization). Definite or probable stent thrombosis (ST) rates were evaluated. RESULTS: In adjusted comparisons between OCT and IVUS groups, there was no significant difference in rates of MACE (3.5% vs. 3.5%, P = 1.000) and ST (0% vs. 0.9%, P = 1.000) at 1 year, optimal stent placement (89.5% vs. 92.1%, P = 0.492), and further intervention (7.9% vs.13.2%, P = 0.234), despite OCT significantly more frequently detecting tissue prolapse (97.4% vs. 47.4%, P < 0.001), and numerically more edge dissection (10.5% vs. 4.4%, P = 0.078) or incomplete stent apposition (48.2% vs. 36.8%, P = 0.082). CONCLUSIONS: OCT guidance showed comparable results to IVUS in mid-term clinical outcomes, suggesting that OCT can be an alternative tool for stent placement optimization.

Clinical Outcomes in Patients with Deferred Coronary Lesions according to Disease Severity Assessed by Fractional Flow Reserve.

Data on the clinical outcomes in deferred coronary lesions according to functional severity have been limited. This study evaluated the clinical outcomes of deferred lesions according to fractional flow reserve (FFR) grade using Korean FFR registry data. Among 1,294 patients and 1,628 lesions in Korean FFR registry, 665 patients with 781 deferred lesions were included in this study. All participants were consecutively categorized into 4 groups according to FFR; group 1: ≥ 0.96 (n = 56), group 2: 0.86-0.95 (n = 330), group 3: 0.81-0.85 (n = 170), and group 4: ≤ 0.80 (n = 99). Primary endpoint was major adverse cardiac events (MACE), a composite of all-cause death, myocardial infarction, and target vessel revascularization. The median follow-up period was 2.1 years. During follow-up, the incidence of MACE in groups 1-4 was 1.8%, 7.6%, 8.8%, and 13.1%, respectively. Compared to group 1, the cumulative rate by Kaplan-Meier analysis of MACE was not different for groups 2 and 3. However, group 4 had higher cumulative rate of MACE compared to group 1 (log-rank P = 0.013). In the multivariate Cox hazard models, only FFR (hazard ratio [HR], 0.95; P = 0.005) was independently associated with MACE among all participants. In contrast, previous history of percutaneous coronary intervention (HR, 2.37; P = 0.023) and diagnosis of acute coronary syndrome (ACS) (HR, 2.35; P = 0.015), but not FFR, were independent predictors for MACE in subjects with non-ischemic (FFR ≥ 0.81) deferred coronary lesions. Compared to subjects with ischemic deferred lesions, clinical outcomes in subjects with non-ischemic deferred lesions according to functional severity are favorable. However, longer-term follow-up may be necessary.

Bio-optics based sensation imaging for breast tumor detection using tissue characterization.

The tissue inclusion parameter estimation method is proposed to measure the stiffness as well as geometric parameters. The estimation is performed based on the tactile data obtained at the surface of the tissue using an optical tactile sensation imaging system (TSIS). A forward algorithm is designed to comprehensively predict the tactile data based on the mechanical properties of tissue inclusion using finite element modeling (FEM). This forward information is used to develop an inversion algorithm that will be used to extract the size, depth, and Young's modulus of a tissue inclusion from the tactile data. We utilize the artificial neural network (ANN) for the inversion algorithm. The proposed estimation method was validated by a realistic tissue phantom with stiff inclusions. The experimental results showed that the proposed estimation method can measure the size, depth, and Young's modulus of a tissue inclusion with 0.58%, 3.82%, and 2.51% relative errors, respectively. The obtained results prove that the proposed method has potential to become a useful screening and diagnostic method for breast cancer.

Prospective randomized study to assess the efficacy of site and rate of atrial pacing on long-term progression of atrial fibrillation in sick sinus syndrome: Septal Pacing for Atrial Fibrillation Suppression Evaluation (SAFE) Study.

BACKGROUND: Atrial-based pacing is associated with lower risk of atrial fibrillation (AF) in sick sinus syndrome compared with ventricular pacing; nevertheless, the impact of site and rate of atrial pacing on progression of AF remains unclear. We evaluated whether long-term atrial pacing at the right atrial (RA) appendage versus the low RA septum with (ON) or without (OFF) a continuous atrial overdrive pacing algorithm can prevent the development of persistent AF. METHODS AND RESULTS: We randomized 385 patients with paroxysmal AF and sick sinus syndrome in whom a pacemaker was indicated to pacing at RA appendage ON (n=98), RA appendage OFF (n=99), RA septum ON (n=92), or RA septum OFF (n=96). The primary outcome was the occurrence of persistent AF (AF documented at least 7 days apart or need for cardioversion). Demographic data were homogeneous across both pacing site (RA appendage/RA septum) and atrial overdrive pacing (ON/OFF). After a mean follow-up of 3.1 years, persistent AF occurred in 99 patients (25.8%; annual rate of persistent AF, 8.3%). Alternative site pacing at the RA septum versus conventional RA appendage (hazard ratio=1.18; 95% confidence interval, 0.79-1.75; P=0.65) or continuous atrial overdrive pacing ON versus OFF (hazard ratio=1.17; 95% confidence interval, 0.79-1.74; P=0.69) did not prevent the development of persistent AF. CONCLUSIONS: In patients with paroxysmal AF and sick sinus syndrome requiring pacemaker implantation, an alternative atrial pacing site at the RA septum or continuous atrial overdrive pacing did not prevent the development of persistent AF. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. UNIQUE IDENTIFIER: NCT00419640.

Left ventricular twist and ventricular-arterial coupling in hypertensive patients.

BACKGROUND: Left ventricular (LV) twist is usually influenced by LV hypertrophy resulting from hypertension or vascular stiffness. Vascular stiffness would increase arterial elastance (Ea), whereas LV end-systolic stiffness (Ees) could be influenced by LV hypertrophy. Therefore, in hypertensive patients, we assessed the extent to which ventricular-arterial coupling (VAC; Ea/Ees) affects LV twist, which may be a compensatory mechanism for systolic dysfunction. METHODS: Hypertensive patients (n = 128) and healthy controls (n = 40) underwent conventional and speckle tracking echocardiography including LV twist. Ea and Ees were estimated noninvasively by echocardiography. Patients were divided into 3 tertiles according to the twist angle. Univariate and multivariate regression analyses were performed to test the influence of VAC on twist. RESULTS: Patients in the lowest LV twist tertile had larger LV end-systolic volume, lower ejection fraction, lesser mid-wall fractional shortening (MWFS), and higher LV mass index (LVMI), compared to those with the highest tertile. They showed the lower septal tissue Doppler velocity, and global longitudinal and circumferential strain. With regard to VAC, Ea was similar among 3 groups, but Ees was significantly decreased in patient with lower tertile, resulting in increased VAC (1.1 ± 0.2 vs. 0.9 ± 0.1 vs. 0.7 ± 0.1, P < 0.001). While LV twist showed significant correlations with Ees, MWFS, and LVMI, VAC (ß = -14.92, P < 0.001) was most associated with twist in a multivariate analysis. CONCLUSIONS: LV twist was significantly associated with VAC in accordance with LV function; LV twist and VAC decreased progressively as LV systolic function deteriorated, while being enhanced during the well-compensated phase.

Association of cardio-ankle vascular index with diastolic heart function in hypertensive patients.

Arterial stiffness is an important risk factor of impaired left ventricular (LV) diastolic function as well as systolic dysfunction. The cardio-ankle vascular index (CAVI) and the ambulatory arterial stiffness index (AASI) can evaluate arteriosclerosis. We analyzed the relationship between arterial stiffness and diastolic function, and then compared the two methodologies to assess which method could serve as a more informative tool for diastology. In total, 136 patients with hypertension underwent 24-h ambulatory blood pressure monitoring (ABPM) and echocardiography including ventricular arterial coupling (VAC). Arterial stiffness was estimated using both CAVI and AASI derived from ABPM. Patients were classified into LV diastolic dysfunction and normal function groups. Those with diastolic dysfunction had a higher CAVI and AASI. Aside from LV torsion, mitral inflow parameters, tissue Doppler velocities and VAC showed a significantly greater association with CAVI, relative to AASI. The receiver operating characteristic curve analysis revealed that CAVI [area under the curve (AUC) = 0.869, p < 0.001] provided significantly more favorable accuracy for diastolic dysfunction compared with AASI (AUC = 0.672, p = 0.004). Multiple logistic regression analyses showed that CAVI [Odds ratio (OR) = 5.1, p = 0.009] had a greater association with diastolic dysfunction, relative to age, systolic blood pressure or AASI (OR = 1.4, p = 0.043). This study indicates that CAVI clinically provides diastolic functional information much better in hypertensive patients than AASI.

TNF-α polymorphisms and coronary artery disease: association study in the Korean population.

Coronary artery disease (CAD) results from atherosclerosis, a chronic inflammatory disease mediated in part by proinflammatory cytokines, particularly tumor necrosis factor-α (TNF-α), which is expressed by atherosclerotic plaques. In this study, we investigated whether TNF-α gene promoter polymorphisms affect the incidence of CAD in Koreans by genotyping. 404 Control subjects and 197 patients who previously received a coronary artery stent for the G/A, C/T, and C/A polymorphisms at position -238, -857 and -863, respectively. The G/G, G/A and A/A genotypes at position -238 occurred in 85.8%, 14.2% and 0% CAD patients and 91.8%, 7.9% and 0.3% control subjects, respectively. The G/A polymorphisms at position -238 were significantly associated with CAD when assuming a dominant model of inheritance (OR = 1.87; 95% CI = 1.10-3.20; P = 0.02), and A allele carriers had a significantly increased risk of developing CAD relative to the G allele (OR = 1.74; 95% CI = 1.04-2.92; P = 0.03). However, the polymorphisms at positions -857 and -863 were not associated with CAD. Haplotype-based analysis revealed the CAD and control groups differed significantly in the frequencies of haplotype ACC at positions -238, -857 and -863 (OR = 1.77; 95% CI = 1.05-2.98; P = 0.03). This was confirmed by multivariate analysis after adjusting body mass index and the presence of diabetes and hypertension (OR = 2.06; 95% CI = 1.15-3.68; P = 0.015). Thus, the -238A allele of TNF-α is associated with an increased risk of CAD and could be used as predictor for CAD in Koreans. Further studies are needed to elucidate the clinical implications of these findings.

Impact of home-based exercise training with wireless monitoring on patients with acute coronary syndrome undergoing percutaneous coronary intervention.

Recent studies have suggested a favorable effect of cardiac rehabilitation (CR) on patients with cardiovascular disease. This study aimed to evaluate the impact of home-based exercise training with wireless monitoring on acute coronary syndrome (ACS) patients undergoing percutaneous coronary intervention (PCI). A total of 55 ACS patients undergoing PCI were randomly divided into home based exercise training with wireless monitoring cardiac rehabilitation (CR, n = 26) and usual care (UC, n = 29). Exercise capacity and quality of life (QOL) were evaluated at baseline and after 12 weeks. Change of metabolic equivalent of the tasks, maximal exercise time and QOL were significantly increased (+2.47 vs +1.43, P = 0.021; +169.68 vs +88.31 sec, P = 0.012; and +4.81 vs +0.89, P = 0.022, respectively), and the change of submaximal rate pressure product, and of submaximal rate of perceived exertion were significantly decreased (-28.24 vs -16.21, P = 0.013; and -1.92 vs -1.62, P = 0.018, respectively) in the CR group compared to the UC group after 12 weeks. CR using home-based exercise training with wireless monitoring led to improvement of exercise capacity and QOL relative to conventional care in ACS patients undergoing PCI. Our findings suggest that early scheduled CR may be considered in ACS patients undergoing PCI.

Risk factors between patients with lone and non-lone atrial fibrillation.

Clinical factors such as tall stature, lean body mass, obstructive sleep apnea, alcohol or caffeine, smoking, endurance sports, and genetic factors are proposed as risk factors for lone atrial fibrillation (LAF). The KORAF (KORean Atrial Fibrillation) study is a retrospective multicenter registry that enrolled 3,570 consecutive atrial fibrillation (AF) patients. Data on risk factors were available for 2,133 patients, of whom 398 (18.7%) were identified as having LAF. In univariate analysis, patients with LAF were more likely to be men (82.4% vs 59.8%, P < 0.001) and current smokers (25.9% vs 15.6%, P < 0.01), alcohol drinkers (55.3% vs 31.2%, P < 0.01) and frequent consumers of caffeinated beverages (> 2 cups/day) (31.7% vs 19.3%, P < 0.01), and have a family history of AF (9.0% vs 2.6%, P < 0.001) than the non-LAF patients. Multivariate analysis showed that male gender (OR, 2.30; 95% CI, 1.61-3.27, P < 0.01), family history of AF (OR, 3.12; 95% CI, 1.91-5.12, P < 0.01), current alcohol use (OR, 2.01; 95% CI, 1.46-2.76, P < 0.01), and frequent caffeinated beverage consumption (OR, 1.66; 95% CI, 1.20-2.29, P < 0.01) were independently associated with LAF. In Korean patients, LAF is more closely associated with male gender, family history of AF, current alcohol and frequent caffeinated beverage consumption than non-LAF.

Optical-based artificial palpation sensors for lesion characterization.

Palpation techniques are widely used in medical procedures to detect the presence of lumps or tumors in the soft breast tissues. Since these procedures are very subjective and depend on the skills of the physician, it is imperative to perform detailed a scientific study in order to develop more efficient medical sensors to measure and generate palpation parameters. In this research, we propose an optical-based, artificial palpation sensor for lesion characterization. This has been developed using a multilayer polydimethylsiloxane optical waveguide. Light was generated at the critical angle to reflect totally within the flexible and transparent waveguide. When a waveguide was compressed by an external force, its contact area would deform and cause the light to scatter. The scattered light was captured by a high-resolution camera and saved as an image format. To test the performance of the proposed system, we used a realistic tissue phantom with embedded hard inclusions. The experimental results show that the proposed sensor can detect inclusions and provide the relative value of size, depth, and Young's modulus of an inclusion.

Association of promoter region single nucleotide polymorphisms at positions -819C/T and -592C/A of interleukin 10 gene with ischemic heart disease.

OBJECTIVE: Ischemic heart disease (IHD) is a disease characterized by ischemia of the heart muscle, usually due to coronary artery disease. Interleukin-10 (IL10) is a proinflammatory cytokine known to protect endothelial function. In this study, we investigated the association of promoter region polymorphisms of the IL10 gene with IHD. METHODS: We recruited 313 control and 173 IHD patients. The selected SNPs in IL10 were genotyped using pyrosequencing. RESULTS: SNPs at positions -592C/A and -819C/T were statistically associated with IHD (P = 0.014 and P = 0.037). Similarly, the mean value of C-reactive protein in the C allele at -592C/A and -819C/T was significantly higher than that in the A allele at -592C/A (P = 0.026) and T allele at -819C/T (P = 0.026). The presence of hypertension in the C allele at -592C/A and -819C/T was significantly more frequent than that in the A allele at -592C/A (P = 0.044) and T allele at -819C/T (P = 0.044). In the haplotype of two SNPs (-592C/A and -819C/T), one haplotype (CC) presented an association with IHD (P = 0.012). CONCLUSIONS: These results indicate that the C allele with SNPs at position -592C/A and -819C/T of IL10 gene may be associated with IHD in the Korean population.

Decision-making model for early diagnosis of congestive heart failure using rough set and decision tree approaches.

The accurate diagnosis of heart failure in emergency room patients is quite important, but can also be quite difficult due to our insufficient understanding of the characteristics of heart failure. The purpose of this study is to design a decision-making model that provides critical factors and knowledge associated with congestive heart failure (CHF) using an approach that makes use of rough sets (RSs) and decision trees. Among 72 laboratory findings, it was determined that two subsets (RBC, EOS, Protein, O2SAT, Pro BNP) in an RS-based model, and one subset (Gender, MCHC, Direct bilirubin, and Pro BNP) in a logistic regression (LR)-based model were indispensable factors for differentiating CHF patients from those with dyspnea, and the risk factor Pro BNP was particularly so. To demonstrate the usefulness of the proposed model, we compared the discriminatory power of decision-making models that utilize RS- and LR-based decision models by conducting 10-fold cross-validation. The experimental results showed that the RS-based decision-making model (accuracy: 97.5%, sensitivity: 97.2%, specificity: 97.7%, positive predictive value: 97.2%, negative predictive value: 97.7%, and area under ROC curve: 97.5%) consistently outperformed the LR-based decision-making model (accuracy: 88.7%, sensitivity: 90.1%, specificity: 87.5%, positive predictive value: 85.3%, negative predictive value: 91.7%, and area under ROC curve: 88.8%). In addition, a pairwise comparison of the ROC curves of the two models showed a statistically significant difference (p<0.01; 95% CI: 2.63-14.6).

A hybrid decision support model to discover informative knowledge in diagnosing acute appendicitis.

BACKGROUND: The aim of this study is to develop a simple and reliable hybrid decision support model by combining statistical analysis and decision tree algorithms to ensure high accuracy of early diagnosis in patients with suspected acute appendicitis and to identify useful decision rules. METHODS: We enrolled 326 patients who attended an emergency medical center complaining mainly of acute abdominal pain. Statistical analysis approaches were used as a feature selection process in the design of decision support models, including the Chi-square test, Fisher's exact test, the Mann-Whitney U-test (p < 0.01), and Wald forward logistic regression (entry and removal criteria of 0.01 and 0.05, or 0.05 and 0.10, respectively). The final decision support models were constructed using the C5.0 decision tree algorithm of Clementine 12.0 after pre-processing. RESULTS: Of 55 variables, two subsets were found to be indispensable for early diagnostic knowledge discovery in acute appendicitis. The two subsets were as follows: (1) lymphocytes, urine glucose, total bilirubin, total amylase, chloride, red blood cell, neutrophils, eosinophils, white blood cell, complaints, basophils, glucose, monocytes, activated partial thromboplastin time, urine ketone, and direct bilirubin in the univariate analysis-based model; and (2) neutrophils, complaints, total bilirubin, urine glucose, and lipase in the multivariate analysis-based model. The experimental results showed that the model with univariate analysis (80.2%, 82.4%, 78.3%, 76.8%, 83.5%, and 80.3%) outperformed models using multivariate analysis (71.6%, 69.3%, 73.7%, 69.7%, 73.3%, and 71.5% with entry and removal criteria of 0.01 and 0.05; 73.5%, 66.0%, 80.0%, 74.3%, 72.9%, and 73.0% with entry and removal criteria of 0.05 and 0.10) in terms of accuracy, sensitivity, specificity, positive predictive value, negative predictive value, and area under ROC curve, during a 10-fold cross validation. A statistically significant difference was detected in the pairwise comparison of ROC curves (p < 0.01, 95% CI, 3.13-14.5; p < 0.05, 95% CI, 1.54-13.1). The larger induced decision model was more effective for identifying acute appendicitis in patients with acute abdominal pain, whereas the smaller induced decision tree was less accurate with the test data. CONCLUSIONS: The decision model developed in this study can be applied as an aid in the initial decision making of clinicians to increase vigilance in cases of suspected acute appendicitis.

Prevalence of electrocardiographic findings suggestive of sudden cardiac death risk in 10,867 apparently healthy young Korean men.

BACKGROUND: The objective of this study was to determine the prevalence of electrocardiographic (ECG) findings suggestive of sudden cardiac death risk in apparently healthy young Korean men. METHODS: We administered questionnaires that elicited personal and family histories and performed ECGs on 10,867 male subjects (mean age, 20.9 years). The subjects with abnormal ECG findings underwent echocardiography, a treadmill test, Holter monitoring, a flecainide provocation test, or an electrophysiologic study (EPS) according to the ECG findings and histories. RESULTS: Of the subjects, 5.95% had left ventricular hypertrophy on ECG, but no subjects had hypertrophic cardiomyopathy by echocardiography. The percentage of subjects with a Brugada ECG pattern was 0.90%. We identified one subject with a positive result on the flecainide provocation test. The percentage of subjects with a preexcitation ECG was 0.17%. In two of the subjects, supraventricular tachycardia was induced in the EPS. Of the subjects, 0.05% had epsilon waves, but there were no subjects with arrhythmogenic right ventricular dysplasia/cardiomyopathy by echocardiography. The percentage of subjects with long QT intervals was 0.02%, but there were no arrhythmias on the treadmill test or Holter monitoring. CONCLUSIONS: The prevalence of a Brugada ECG pattern in apparently healthy young men is higher in Korea than other countries.

Two-dimensional strain or strain rate findings in mild to moderate diastolic dysfunction with preserved ejection fraction.

Left ventricular (LV) diastolic dysfunction with preserved ejection fraction is frequently encountered in clinical practice. However, the relations between LV filling patterns and myocardial function by using two-dimensional (2D) speckle tracking imaging are not well known. One hundred thirteen individuals (mean age 59 ± 12 years), referred for a clinically indicated echocardiogram, underwent standard and 2D strain echocardiography. The subjects were divided into groups on the basis of diastolic function by using standard Doppler indices, and we compared 2D strain/strain rate parameters between groups. Subjects with mild to moderate LV diastolic dysfunction showed a high left atrial volume index (LAVI) and early mitral inflow to annular velocity ratio. With regard to 2D strain/strain rate, the severity of diastolic dysfunction was associated with low peak strain, and low systolic and early diastolic strain rate of longitudinal, circumferential and radial deformations, whereas the late diastolic strain rate was not. In multivariate analysis, LAVI and circumferential early diastolic strain rate were most associated with the severity of diastolic dysfunction, although longitudinal and circumferential peak strains were also of significant correlation. In addition to LAVI, the circumferential early diastolic strain rate would be a useful parameter in the assessment of the severity of diastolic dysfunction with preserved ejection fraction.

Role of the alternans of action potential duration and aconitine-induced arrhythmias in isolated rabbit hearts.

Under conditions of Na(+) channel hyperactivation with aconitine, the changes in action potential duration (APD) and the restitution characteristics have not been well defined in the context of aconitine-induced arrhythmogenesis. Optical mapping of voltage using RH237 was performed with eight extracted rabbit hearts that were perfused using the Langendorff system. The characteristics of APD restitution were assessed using the steady-state pacing protocol at baseline and 0.1 µM aconitine concentration. In addition, pseudo-ECG was analyzed at baseline, and with 0.1 and 1.0 µM of aconitine infusion respectively. Triggered activity was not shown in dose of 0.1 µM aconitine but overtly presented in 1.0 µM of aconitine. The slopes of the dynamic APD restitution curves were significantly steeper with 0.1 µM of aconitine than at baseline. With aconitine administration, the cycle length of initiation of APD alternans was significantly longer than at baseline (287.5 ± 9.6 vs 247.5 ± 15.0 msec, P = 0.016). The functional reentry following regional conduction block appears with the progression of APD alternans. Ventricular fibrillation is induced reproducibly at pacing cycle length showing a 2:1 conduction block. Low-dose aconitine produces arrhythmogenesis at an increasing restitution slope with APD alternans as well as regional conduction block that proceeds to functional reentry.