Accessory pathway localization with probabilistic density maps generated by a mobile application: Assessment of a full pre-excitation net-vector method

INTRODUCTION

Precise electrocardiographic localization of accessory pathways (AP) can be challenging. Seminal AP localization studies were limited by complexity of algorithms and sample size. We aimed to create a nonalgorithmic method for AP localization based on color-coded maps of AP distribution generated by a web-based application.

METHODS

APs were categorized into 19 regions/types based on invasive electrophysiologic mapping. Preexcited QRS complexes were categorized into 6 types based on polarity and notch/slur. For each QRS type in each lead the distribution of APs was visualized on a gradient map. The principle of common set was used to combine the single lead maps to create the distribution map for AP with any combination of QRS types in several leads. For the validation phase, a separate cohort of APs was obtained.

RESULTS

A total of 800 patients with overt APs were studied. The application used the exploratory data set of 553 consecutive APs and the corresponding QRS complexes to generate AP localization maps for any possible combination of QRS types in 12 leads. Optimized approach (on average 3 steps) for evaluation of preexcited electrcardiogram was developed. The area of maximum probability of AP localization was pinpointed by providing the QRS type for the subsequent leads. The exploratory data set was validated with the separate cohort of APs (n = 256); p = .23 for difference in AP distribution.

CONCLUSIONS

In the largest data set of APs to-date, a novel probabilistic and semi-automatic approach to electrocardiographic localization of APs was highly predictive for anatomic localization.

Comparison of six risk scores for the prediction of atrial fibrillation recurrence after cryoballoon-based ablation and development of a simplified method, the 0-1-2 PL score

INTRODUCTION

There are several prognostic scores for the assessment of risk of atrial fibrillation (AF) recurrence post ablation procedure. However, the use of these complex scores is difficult and the validation on different populations brought divergent results. Our goal was to compare the performance of these risk scores as the basis for the development of a new, simplified score based only on few universally predictive variables.

METHODS

All cryoballoon-based AF ablations performed in a single-center over a 10-year period were prospectively analyzed with regard to AF recurrence. This served to analyze the performance of APPLE, CAAP-AF, SCALE-CryoAF, MB-LATER, CHADS2, and CHA2DS2-VASc risk scores.

RESULTS

A total of 597 patients, mostly (78.1%) with paroxysmal AF were studied. Analyzed risk scores performed poorer than in the original publications because some risk factors were not predictive of AF recurrence. A simplified score named 0-1-2 PL, composed of just two universally predictive variables, AF type (1 point for Persistent AF) and LA dimension (1 point for LA size >45 mm) was developed. The 0-1-2 PL score stratified patients into low risk (0 points), intermediate risk (1 point), and high risk categories (2 points) which were related to a 2-year risk of AF recurrence of 21%, 37%, and 55%, respectively. This score had C-statistics (0.620) higher/comparable to other investigated much more complex scores.

CONCLUSION

The assessment of risk of AF recurrence at the pre-ablation stage can be simplified without compromising accuracy. This could help to popularize risk assessment and standardization of AF management.

Comparison of blood pressure values and expression of genes associated with hypertension in children before and after hematopoietic cell transplantation

Hypertension is a well-known late effect of hematopoietic cell transplantation (HCT), but no markers predicting its development are known. Our aim was to assess short-term blood pressure (BP) values and expressions of hypertension-associated genes as possible markers of hypertension in children treated with HCT. We measured systolic blood pressure (SBP) and diastolic blood pressure (DBP), using both office procedure and ambulatory BP monitoring (ABPM) in children before HCT and after a median of 6 months after HCT. We compared the results with two control groups, one of healthy children and another of children with simple obesity. We also performed microarray analysis of hypertension-associated genes in patients treated with HCT and children with obesity. We found no significant differences in SBP and DBP in patients before and after HCT. We found significant differences in expressions of certain genes in patients treated with HCT compared with children with obesity. We concluded that BP values in short-term follow-up after HCT do not seem to be useful predictors of hypertension as a late effect of HCT. However, over expressions of certain hypertension-associated genes might be used as markers of hypertension as a late effect of HCT if this is confirmed in larger long-term studies.

Electrocardiographic characterization of non-selective His-bundle pacing: validation of novel diagnostic criteria

AIMS

Permanent His-bundle (HB) pacing is usually accompanied by simultaneous capture of the adjacent right ventricular (RV) myocardium-this is described as a non-selective (ns)-HB pacing. It is of clinical importance to confirm HB capture using standard electrocardiogram (ECG). Our aim was to identify ECG criteria for loss of HB capture during ns-HB pacing.

METHODS AND RESULTS

Patients with permanent HB pacing were recruited. Electrocardiograms during ns-HB pacing and loss of HB capture (RV-only capture) were obtained. Electrocardiogram criteria for loss/presence of HB capture were identified. In the validation phase, these criteria and the 'HB ECG algorithm' were tested using a separate, sizable set of ECGs. A total of 353 ECG (226 ns-HB and 128 RV-only) were obtained from 226 patients with permanent HB pacing devices. QRS notch/slur in left ventricular leads and R-wave peak time (RWPT) in lead V6 were identified as the best features for differentiation. The 'HB ECG algorithm' based on these features correctly classified 87.1% of cases with sensitivity and specificity of 93.2% and 83.9%, respectively. The criteria for definitive diagnosis of ns-HB capture (no QRS slur/notch in Leads I, V1, V4-V6, and the V6 RWPT ≤ 100 ms) presented 100% specificity.

CONCLUSION

A novel ECG algorithm for the diagnosis of loss of HB capture and criteria for definitive confirmation of HB capture were formulated and validated. The algorithm might be useful during follow-up and the criteria for definitive confirmation of ns-HB capture offer a simple and reliable ancillary procedural endpoint during HB device implantation.

Gastrointestinal peptides in children before and after hematopoietic stem cell transplantation

BACKGROUND

Gastrointestinal tract function and it's integrity are controlled by a number of peptides whose secretion is influenced by severe inflammation. In stomach the main regulatory peptide is ghrelin. For upper small intestine cholecystokinin and lower small intestine glucagon-like peptide- 1 are secreted, while fibroblast growth factor-21 is secreted by several organs, including the liver, pancreas, and adipose tissue [12]. Hematopoietic stem cell transplantation causes serious mucosal damage, which can reflect on this peptides.

METHODS

The aim of the study was to determine fasting plasma concentrations of ghrelin, cholecystokinin, glucagon- like peptide-1, and fibroblast growth factor-21, and their gene expressions, before and 6 months after hematopoietic stem cell transplantation.27 children were studied, control group included 26 healthy children.

RESULTS

Acute graft versus host disease was diagnosed in 11 patients (41%, n = 27). Median pre-transplantation concentrations of gastrointestinal peptides, as well as their gene expressions, were significantly lower in studied group compared with the control group. Only median of fibroblast growth factor-21 concentration was near-significantly higher before stem cell transplantation than in the control group. The post-hematopoietic transplant results revealed significantly higher concentrations of the studied peptides (except fibroblast growth factor-21) and respective gene expressions as compare to pre transplant results. Median glucagone like peptide-1 concentrations were significantly decreased in patients with features of acute graft versus host disease. Moreover, negative correlation between glucagone like peptide-1 concentrations and acute graft versus host disease severity was found.

CONCLUSIONS

Increased concentrations and gene expressions of gastrointestinal tract regulation peptides can be caused by stimulation of regeneration in the severe injured organ. Measurement of these parameters may be a useful method of assessment of severity of gastrointestinal tract complications of hematopoietic stem cell transplantation.

Malignant ventricular arrhythmias and other complications of untreated accessory pathways: an analysis of prevalence and risk factors in over 600 ablation cases

BACKGROUND

The presence of accessory pathways (APs) is a risk factor for sudden cardiac death and other clinical complications.

AIMS

We aimed to characterize all adverse events likely related to the presence of APs in patients referred for AP ablation and to identify risk factors for malignant arrhythmias.

METHODS

We performed a retrospective analysis of consecutive patients referred for AP ablation from 2002 to 2017. Electrocardiograms, electrophysiological system records, and hospital discharge notes were reviewed. We collected data concerning symptoms before ablation, occurrence of ventricular fibrillation or malignant atrial fibrillation (AF), as well as other complications related to APs.

RESULTS

We identified 602 patients with APs. Serious AP‑related events were observed in 41 patients, including 14 sudden cardiac arrests (1 death) and 16 pre–cardiac arrest events. Other complications included strokes, pulmonary edema, heart failure, and unnecessary device implantation. The risk of malignant arrhythmias decreased with a longer shortest preexcited RR interval (per 10 ms: odds ratio [OR], 1.3; 95% CI, 1.16–1.47) and increased with age (per 10 years: OR, 1.29; 95% CI, 1.06–1.57). The presence of inducible AF, but not sole atrioventricular reentrant tachycardia, increased the risk for malignant arrhythmias when compared with patients without any inducible arrhythmias.

CONCLUSIONS

Patients with APs referred for ablation commonly present with various adverse events. The predictive value of clinical risk factors for malignant arrhythmias is too low to prevent devastating consequences. When high safety and efficacy of AP ablation are ensured, even a low risk of sudden death is unacceptable and a lower threshold for prophylactic ablation should be used to prevent AP‑related adverse events.

CHADS2 and CHA2DS2-VASc scores as tools for long-term mortality prognosis in patients with typical atrial flutter after catheter ablation

BACKGROUND

The CHADS2 and CHA2DS2-VASc scores were shown to predict mortality in patients with atrial fibrillation. However, pathophysiology and treatment outcomes of atrial fibrillation and typical atrial flutter (AFL) differ. Consequently, the prognosis of patients with AFL can also be different.

AIMS

The aim of the study was to assess CHADS2 and CHA2DS2‑VASc scores as mortality predictors in patients with typical AFL.

METHODS

Large cohort of consecutive patients with typical AFL who underwent catheter ablation was retrospectively analyzed. The CHADS2 and CHA2DS2‑VASc were calculated using hospital record data. All-cause mortality data was obtained from the registry of national personal identification numbers. The Kaplan-Meier method and multivariable Cox proportional hazard models were applied for survival and hazard ratio analyses, respectively.

RESULTS

A total of 469 patients hospitalized for typical AFL ablation were enrolled (mean [SD] age, 63.7 [12.2] years; male sex, 69.1%). Patients were followed from 2 to 12 years resulting in 2974 patient‑years of follow‑up. The Kaplan-Meier survival analysis revealed a negative impact of each component of the CHADS2 and CHA2DS2‑VASc scores on survival with the exception of stroke (not significant) and female sex (related to abetter survival). Consequently, higher scores were predictive of higher all‑cause mortality rates (2.7%-54% at 10 years); the CHA2DS2‑VASc score was equally predictive as the CHADS2 score.

CONCLUSIONS

In patients referred for typical AFL ablation, the CHADS2 score can be applied for prognostic assessment. A successful AFL ablation procedure should not divert the attention from recognizing and addressing other medical issues that have an impact on long‑term mortality, which remains very high in this population of patients.

Comparison of four LBBB definitions for predicting mortality in patients receiving cardiac resynchronization therapy

BACKGROUND

Left bundle branch block (LBBB) is considered an important prognostic parameter in cardiac resynchronization therapy (CRT). We aimed to evaluate, in a sizeable cohort of patients with CRT, long-term mortality, and morbidity according to four different electrocardiographic definitions of LBBB.

METHODS

This longitudinal cohort study included consecutive patients who underwent CRT device implantation in our institution in years 2006-2014. Two endpoints were assessed: (a) death from any cause or urgent heart transplantation, and (b) death from any cause or heart failure admission. All preimplantation ECGs were analyzed by three physicians blinded to outcome and categorized as LBBB or non-LBBB according to four definitions.

RESULTS

A total of 552 CRT patients entered survival analysis. According to the conventional definition, 350 (63.4%) patients had LBBB, and the Marriott, WHO/AHA, and Strauss definitions identified LBBB in 254 (46.0%), 218 (39.5%) and 226 (40.9%) patients, respectively. During the 9 years of observation, 232 patients died, the combined endpoint was met by 292 patients. The Strauss LBBB definition was significantly better to the other definitions in predicting survival (Kaplan-Meier analysis with comparison of C-statistics). Multivariate Cox regression model showed that LBBB was the major determinant of all-cause mortality with the Strauss definition having the lowest hazard ratio (0.51) of the four studied definitions.

CONCLUSIONS

Criteria included in various definitions of LBBB result in a diagnosis of LBBB in divergent groups of patients. Differences in LBBB definitions have clinical consequences, as patients without 'complete/true' LBBB probably get no mortality benefit from CRT.

Circadian blood pressure profiles and ambulatory arterial stiffness index in children and adolescents with congenital adrenal hyperplasia due to 21-hydroxylase deficiency in relation to their genotypes

OBJECTIVE

Lifelong steroid therapy and exposure to adrenal androgen excess in 21-hydroxylase deficient (21-OHD) congenital adrenal hyperplasia (CAH) children and adolescents may modify circadian blood pressure profile and result in vascular complications. The objective of the study was to evaluate vascular abnormalities in 21-OHD children and adolescents in relation to their genotypes.

DESIGN

A cross-sectional study conducted at a tertiary referral center.

PATIENTS

Seventy patients with 21-OHD CAH (27 boys), aged from 3 to 17.9 years: 9 with nonclassic CAH, 61 with classic CAH: 10 with simple virilising (SV) and 51 with salt wasting CAH (13-Del/Del, 8-Del/I2G, 7-I2G/I2G and 23-other genotypes).

MAIN OUTCOMES MEASURES

The assessment of systolic and diastolic BP (SBP, DBP) loads, night dip% and arterial ambulatory stiffness index (AASI) in 21-OHD CAH patients.

Specificity of wide QRS complex tachycardia criteria and algorithms in patients with ventricular preexcitation

BACKGROUND

Despite substantial progress in the field of differentiation between ventricular tachycardia (VT) and supraventricular tachycardia (SVT) with wide QRS complexes, differentiation between VT and preexcited SVT remains largely unresolved due to significant overlap in QRS morphology. Our aim was to assess the specificities of various single ECG criteria and sets of criteria (Brugada algorithm, aVR algorithm, Steurer algorithm, and the VT score) for diagnosis of VT in a sizable cohort of patients with preexcitation.

METHODS

We performed a retrospective study of consecutive accessory pathway ablation procedures to identify preexcited tachycardias. Among 670 accessory pathway ablation procedures, 329 cases with good quality ECG with either bona fide preexcited SVT (n = 30) or a surrogate preexcited SVT (fast paced atrial rhythm with full preexcitation, n = 299) were identified. ECGs were analyzed with the use of wide QRS complex algorithms/criteria to determine specificities of these methods.

RESULTS

The Steurer algorithm and VT score (≥3 points), with specificities of 97.6% and 96.1%, respectively, were significantly (p < .01) more specific for the diagnosis of VT than Brugada algorithm, aVR algorithm, and Pava criterion with specificities of 31%, 11.6%, and 57.1%, respectively. The first step of the Brugada algorithm and the first step of the aVR algorithm had also high specificities of 93.3% and 96.0%, respectively.

CONCLUSION

There are sufficient electrocardiographical differences between VT and preexcited SVT to allow electrocardiographic differentiation. VT score, Steurer algorithm, and some single criteria do not overdiagnose VT in patients with preexcitation.

Contemporary outcomes of catheter ablation of accessory pathways: complications and learning curve

BACKGROUND AND AIM

The aim of this study was to examine contemporary results of accessory pathway (AP) ablation in a sizeable number of patients, focusing on periprocedural complications and the learning curve.

METHODS

We performed a retrospective cohort study of consecutive AP ablation procedures at three centresby the same operator. In total 629 electrophysiological studies and 610 AP ablation procedures were performed in 570 patients (age: 33 ± 18.9 years).

RESULTS

There was one (0.16%) serious and there were 14 (2.3%) minor periprocedural complications. Five hundred and ninety APs were successfully ablated: single/multiple procedure success was 93.4%/96.7%, while the average fluoroscopy time was 13.5 min. There was significantly higher success and less fluoroscopy use with increased experience, while periprocedural complications seemed evenly distributed over the years. The learning was most pronounced for the first 120 cases. However, the learning curve fully flattened only after approximately 400 ablations.

CONCLUSIONS

This study suggests that in the modern era AP ablation is safer than it was in the first two decades after the introduction of catheter ablation of APs. Perhaps, in experienced centres there should be a lower threshold for referring asymptomatic/mildly symptomatic patients with pre-excitation for electrophysiological study.

Correlations between electrocardiogram and biomarkers in acute pulmonary embolism: Analysis of ZATPOL-2 Registry

BACKGROUND

Electrocardiography (ECG) is still one of the first tests performed at admission, mostly in patients (pts) with chest pain or dyspnea. The aim of this study was to assess the correlation between electrocardiographic abnormalities and cardiac biomarkers as well as echocardiographic parameter in patients with acute pulmonary embolism.

METHODS

We performed a retrospective analysis of 614 pts. (F/M 334/280; mean age of 67.9 ± 16.6 years) with confirmed acute pulmonary embolism (APE) who were enrolled to the ZATPOL-2 Registry between 2012 and 2014.

RESULTS

Elevated cardiac biomarkers were observed in 358 pts (74.4%). In this group the presence of atrial fibrillation (p = .008), right axis deviation (p = .004), S₁ Q₃ T₃ sign (p < .001), RBBB (p = .006), ST segment depression in leads V₄ -V₆ (p < .001), ST segment depression in lead I (p = .01), negative T waves in leads V₁ -V₃ (p < .001), negative T waves in leads V₄ -V₆ (p = .005), negative T waves in leads II, III and aVF (p = .005), ST segment elevation in lead aVR (p = .002), ST segment elevation in lead III (p = .0038) was significantly more frequent in comparison to subjects with normal serum level of cardiac biomarkers. In multivariate regression analysis, clinical predictors of "abnormal electrocardiogram" were as follows: increased heart rate (OR 1.09, 95% CI 1.02-1.17, p = .012), elevated troponin concentration (OR 3.33, 95% CI 1.94-5.72, p = .000), and right ventricular overload (OR 2.30, 95% CI 1.17-4.53, p = .016).

CONCLUSIONS

Electrocardiographic signs of right ventricular strain are strongly related to elevated cardiac biomarkers and echocardiographic signs of right ventricular overload. ECG may be used in preliminary risk stratification of patient with intermediate- or high-risk forms of APE.

Clinical effectiveness and toxicity of second-line irinotecan in advanced gastric and gastroesophageal junction adenocarcinoma: a single-center observational study

BACKGROUND

Randomized clinical trials showed improved overall survival (OS) of advanced gastroesophageal adenocarcinoma (GEA) patients treated with second-line taxane or irinotecan. However, most data on irinotecan efficacy in this setting come from large Asian trials. We retrospectively analyzed clinical effectiveness and toxicity of irinotecan in a cohort of patients with advanced GEA treated in our department.

METHODS

Advanced GEA patients who received at least one cycle of second-line irinotecan were eligible for inclusion. Irinotecan was administered every 3 weeks at an initial dose of 250 mg/m² of body surface area with subsequent gradual (every 50 mg/m²) dose escalation up to 350 mg/m², in the case of good treatment tolerance. OS was estimated using the Kaplan-Meier method. A multivariate Cox regression analysis was used to examine the association between clinical and laboratory parameters and survival.

RESULTS

A total of 48 patients were identified. Median OS was 6.2 months [95% confidence interval (CI): 3.9-7.6]. In multivariate analysis, age < 65 years, baseline total lymphocyte count (TLC) < 1500/µl and presence of peritoneal metastases were associated with shorter OS. Most adverse events were grade 1-2 and included: anemia (52.3%), leukocytopenia (40.9%), neutropenia (59.1%), nausea (25.0%), vomiting (31.8%), diarrhea (31.8%), anorexia (29.5%) and fatigue (43.2%). Febrile neutropenia occurred in three patients (6.8%). Nine patients (20.5%) experienced a toxicity grade 3-4 of any kind.

CONCLUSIONS

This retrospective analysis confirms clinical effectiveness and manageable toxicity of second-line irinotecan in an unselected cohort of advanced GEA patients. Age < 65 years, baseline TLC < 1500/µl and presence of peritoneal metastases were independent prognostic factors associated with shorter OS.

Electrocardiographic Parameters Indicating Worse Evolution in Patients with Acquired Long QT Syndrome and Torsades de Pointes

BACKGROUND

Acquired long QT syndrome (a-LQTS) is associated with life-threatening ventricular arrhythmias, mainly torsades de pointes (TdP). ECG parameters predicting evolving into ventricular fibrillation (VF) are ill defined.

AIMS

To determine ECG parameters preceding and during TdP associated with higher risk of developing VF.

METHODS

We analyzed 151 episodes of TdP, recorded in 28 patients with a-LQTS (mean QTc 638 ms ± 57).

RESULTS

All 28 patients had prolonged QT interval, (mean QTc 638 ms ± 57) ranging from 502 ms to 858 ms correcting by Bazett's formula. The mean TdP heart rate was 218 bpm ± 38 (mean cycle length of TdP 274 ± 47 ms). We classified TdPs episodes into "slower"-TdP (s-TdP) < 220 bpm (range from 145-220 bpm) observed in 81 (53.6%) episodes and "faster"-TdP (f-TdP) ≥ 220 bpm (ranged from 221-281 bpm) observed in 70 (46.4%) episodes. Among 151 episodes of TdP, 21 (13.9%) were unstable (converted into VF). Out of 81 episodes of "slower"-TdP only 2 (2.5%) episodes converted into VF. The mean coupling interval (CI) of the PVC initiating TdP was 510 ms ± 118, the pause-RR interval was 1147 ms ± 335, the prematurity index (PI) of PVC that initiated TdP was 0.45 ± 0.13. The mean cycle length variability of TdP (VRV-TdP) was 30.79 ms ± 19.7. U wave was observed in 86 episodes (56.9%), among that in 69 episodes, the U/T wave ratio was > 1. Macro T wave alternans was observed in 4 patients. The QT interval was not different in patients with VF(+) and VF(-) episodes, 633 ± 60 and 639 ± 57, respectively.

CONCLUSIONS

Some electrocardiographic parameters can be helpful in determining the risk of TdP evolving into VF. The slower ventricular rate (< 220 bpm), the higher rate instability (VRV > 30 ms) and the short episodes < 20 beats could predict benign evolution.

Function of the Respiratory System in Elderly Patients After Aortic Valve Replacement

OBJECTIVE

To compare the function of the respiratory system after aortic valve replacement through median sternotomy (AVR) or the minimally invasive right anterior minithoracotomy (RAT-AVR) approach among elderly (aged≥75 years) patients.

DESIGN

Observational cohort study.

SETTINGS

University hospital.

PARTICIPANTS

The study included 65 elderly patients scheduled for RAT-AVR and 82 for standard AVR.

INTERVENTIONS

Pulmonary function tests (PFT) were performed preoperatively, 1 week, 1 month, and 3 months after surgery. In addition, respiratory complications were analyzed.

MEASUREMENTS AND MAIN RESULTS

Respiratory complications occurred in 12.3% of patients in the RAT-AVR group and 18.3% of patients in the AVR group (p = 0.445). Mechanical ventilation time in the intensive care unit was 7.7±3.6 hours for RAT-AVR patients and 9.7±5.4 hours for AVR patients (p = 0.003). Most PFT were worse in the AVR group than in the RAT-AVR group when performed 1 week after surgery. After 1 month, forced expiratory volume in the first second, vital capacity, and total lung capacity differed significantly in favor of the RAT-AVR group (p = 0.002, p<0.001, and p = 0.001, respectively). After 3 months, the PFT parameters still had not returned to preoperative values, but the differences were no longer significant between the RAT-AVR and AVR groups. The multivariable median regression analysis demonstrated that RAT-AVR surgery was a key factor in a patient's higher postoperative PFT parameter values.

CONCLUSIONS

RAT-AVR surgery resulted in shorter postoperative mechanical ventilation time and improved the recovery of pulmonary function in elderly patients, but it did not reduce the incidence of pulmonary complications when compared with surgery performed through a median sternotomy.

Respiratory System Function in Patients after Aortic Valve Replacement through Right Anterior Minithoracotomy

Background The aim of the study was to analyze respiratory system function after minimally invasive aortic valve replacement through right anterior minithoracotomy (RAT-AVR). Methods An observational study of 187 patients electively scheduled for RAT-AVR between January 2010 and December 2013. Pulmonary complications were analyzed and spirometry examinations were performed preoperatively, 1 week, 1 month, and 3 months after surgery. Results Hospital mortality was 1.1%. A double-lumen intratracheal tube was used in 88.2% and single-lumen intratracheal tube was used in 11.8% of patients. Pulmonary complications occurred in 10.8% of the patients. Prolonged (>24 hours) mechanical ventilation time was present in five patients (2.7%). The reasons were stroke (n = 1), perioperative myocardial infarction (n = 2), and pneumothorax (n = 2). Right pleural effusion, which occurred in 7.7% (n = 14) of patients, was the most frequent respiratory system complication. One week after surgery, the spirometry parameters decreased in comparison to the preoperative period, then after 3 months statistically significant improvement occurred; however, the spirometry parameters still had not returned to preoperative values. Multivariable median regression analysis shows that the presence of chronic obstructive pulmonary disease and pulmonary complications were associated with lower values of forced expiratory volume in 1 second after surgery. There was no statistically significant difference regarding spirometry values or incidence of pulmonary complications after surgery between patients in whom single-lung or double-lung ventilation was applied. Conclusion Pulmonary functional status measured with spirometry parameters was diminished after RAT-AVR surgery. Single-lung ventilation did not result in a higher rate of respiratory complications after RAT-AVR surgery.

Concentrations of adipokines in children before and after hematopoietic stem cell transplantation

Adipokines have multiple effects, including regulation of glucose metabolism, cell proliferation, inflammation, and angiogenesis. The aim of the study was to determine plasma concentrations of adiponectin, apelin, leptin, and resistin as well as soluble leptin receptor in pediatric hematopoietic stem cell transplantation (HSCT). The expression of genes encoding the studied peptides was measured using microarray technique. Plasma concentrations of tested peptides were measured before and after oral glucose tolerance test in children treated with HSCT (n = 38) and in healthy controls (n = 26). The peptides were measured before HSCT (pre-HSCT group; n = 38) and after a median of 6 months after HSCT (post-HSCT group; n = 27 of 38 children treated with HSCT). In addition, measurements of fasting plasma glucose, insulin, lipids, and high-sensitivity C-reactive protein (hsCRP) were performed. In both HSCT groups, atherogenic lipid profile, low-grade systemic inflammation was observed. Leptin, adiponectin, and resistin also appear to be good markers of disease burden and low-grade systemic inflammation. Adipokines may be good markers of disease burden and may influence metabolic complications of HSCT. Future studies on larger groups of patients will explain if changes of the concentrations of leptin, adiponectin, and apelin observed in our study and confirmed by expression levels influence engraftment and reconstitution of cell lines.

Validation of Standard and New Criteria for the Differential Diagnosis of Narrow QRS Tachycardia in Children and Adolescents

To establish an appropriate treatment strategy and determine if ablation is indicated for patients with narrow QRS complex supraventricular tachycardia (SVT), analysis of a standard 12-lead electrocardiogram (ECG) is required, which can differentiate between the 2 most common mechanisms underlying SVT: atrioventricular nodal reentry tachycardia (AVNRT) and orthodromic atrioventricular reentry tachycardia (OAVRT). Recently, new, highly accurate electrocardiographic criteria for the differential diagnosis of SVT in adults were proposed; however, those criteria have not yet been validated in a pediatric population.All ECGs were recorded during invasive electrophysiology study of pediatric patients (n = 212; age: 13.2 ± 3.5, range: 1-18; girls: 48%). We assessed the diagnostic value of the 2 new and 7 standard criteria for differentiating AVNRT from OAVRT in a pediatric population.Two of the standard criteria were found significantly more often in ECGs from the OAVRT group than from the AVNRT group (retrograde P waves [63% vs 11%, P < 0.001] and ST-segment depression in the II, III, aVF, V1-V6 leads [42% vs 27%; P < 0.05]), whereas 1 standard criterion was found significantly more often in ECGs from the AVNRT group than from the OAVRT group (pseudo r' wave in V1 lead [39% vs 10%, P < 0.001]). The remaining 6 criteria did not reach statistical significance for differentiating SVT, and the accuracy of prediction did not exceed 70%. Based on these results, a multivariable decision rule to evaluate differential diagnosis of SVT was performed.These results indicate that both the standard and new electrocardiographic criteria for discriminating between AVNRT and OAVRT have lower diagnostic values in children and adolescents than in adults. A decision model based on 5 simple clinical and ECG parameters may predict a final diagnosis with better accuracy.

The association between metabolic complications and arterial hypertension in obese adolescents

OBJECTIVE

There is increasing evidence for the contribution of obesity and its metabolic sequels in the development of arterial hypertension (AH).

METHODS

The casual blood pressure (CBP), 24hABPM, ambulatory arterial stiffness index (AASI) and symmetric (sAASI) ambulatory arterial stiffness index (both derived from a 24 h ABPM) and selected laboratory tests were performed in 130 obese (mean BMI SDS 4.2) adolescents at the mean age of 13.7 years.

RESULTS

AH was diagnosed in 36.2%, and in 33.8% patients on the basis of CBP and 24hABPM respectively. There were significant correlations between: CBPSBP insulin level (fasting r=0.19, p=0.03 and post glucose load r=0.18, p=0.04), HOMA-IR (r=0.18, p=0.04), and uric acid (UA) level (r=0.35, p<0.001); CBPDBP and UA level (r=0.23, p=0.01). There were significant correlations between 24hABPM parameters and cortisol secretion: dSBP and urinary free cortisol (r=0.3, p=0.03), nDBP and nMAP and cortisol rhythm (r=0.21, p=0.03). There a correlation between sAASI and creatinine level (r=0.29, p=0.002) and negative correlation between AASI and eGFR (r=-0.23, p=0.009).

CONCLUSIONS

The increase of the CBP parameters is associated with insulin resistance and hyperuricemia, while the increase of ABPM results is proportional to the cortisol secretion in obese adolescents.

Perioperative Outcomes of Minimally Invasive Aortic Valve Replacement through Right Anterior Minithoracotomy

Background The aim of the study was to analyze perioperative outcomes after minimally invasive aortic valve replacement through right anterior minithoracotomy (RAT-AVR). Patient selection criteria, anesthesia protocol, and surgical technique are presented. Methods A retrospective analysis of 194 patients electively scheduled for RAT-AVR was performed between January 2009 and June 2013. For preoperative planning, computed tomography was performed. Results Among studied patients, there were 48.5% females and 51.5% males with a mean age of 69.9 ± 9.2 years. The predicted mortality calculated with EuroSCORE II was 3.2 ± 0.9%, and observed mortality of RAT-AVR patients was 1.5%. Finally, RAT-AVR surgery was performed on 97.9% of patients (n = 190). Reasons for conversions to median sternotomy were bleeding from aortotomy site (n = 4) and from the right ventricle after epicardial pacing wire placement (n = 1), pleural adhesions (n = 2), and ascending aorta hidden under the sternum (n = 2). The second intercostal space was chosen for surgical access in 97.9% of patients.There were 3.6% reoperations for bleeding: aortotomy place (n = 1), epicardial pacing wire placement (n = 3), right lung tear (n = 2), and intercostal vessels (n = 1). The intensive care unit and hospital length of stays were 1.3 ± 1.2 and 5.7 ± 1.4 days, respectively. Strokes were present in 1.5% of patients. The perioperative complications rate diminished with time, occurring in 44.9% of the patients between 2009 and 2010 and in 15.6% of patients in 2013. Conclusions RAT-AVR can be safely performed without increased morbidity and mortality. Reduced complication rates over time reflect a learning curve.

Expression of the central obesity and Type 2 Diabetes mellitus genes is associated with insulin resistance in young obese children

OBJECTIVES

The assessment of the health consequences associated with obesity in young children is challenging. The aims of this study were: (1) to compare insulin resistance indices derived from OGTT in obese patients and healthy control (2) to analyze central obesity and Type 2 Diabetes genes expression in obese children, with special attention to the youngest group (< 10 years old).

PATIENTS AND METHODS

The study included 49 children with obesity (median age 13.5 years old), and 25 healthy peers. Biochemical blood tests and expression of 11 central obesity and 33 Type 2 Diabetes genes was assessed.

RESULTS

A significant difference in insulin resistance between obese and non-obese adolescents was observed in all studied indices (mean values of the insulin levels: 24.9 vs. 9.71 mIU/L in T0, 128 vs. 54.7 mIU/L in T60 and 98.7 vs. 41.1 mIU/L in T120 respectively; AUC: 217 vs. 77.2 ng/ml*h, mean values of B% (state beta cell function), S% (insulin sensitivity), and IR were 255 (±97) vs. 135 (±37.8), 46.6 (±37.3) vs. 84.2 (±29.6) and 3 (±1.55) vs. 1.36 (±0,56); HIS, WBIS and ISIBel median 3.89, 44.7, 0.73 vs. 8.57, 110, 2.25. All comparisons differed significantly p<0.001). Moreover, insulin sensitivity was significantly better in the older obese group (>10 years old): median AUC 239 vs. 104 ng/ml*h, and HIS, WBIS and ISIBel 3.57, 38, 0.67 vs. 6.23, 75.6, 1.87 respectively in the obese older compared to the obese younger subgroup, p<0.05. The expression of 64% of the central obesity genes and 70% of Type 2 Diabetes genes was higher in the obese compared to control groups. The differences were more pronounced in the younger obese group.

CONCLUSION

Insulin resistance may develop in early stage of childhood obesity and in very young children may be associated with higher expression of the central obesity and Type 2 Diabetes genes.

Relation of atrial fibrillation and right-sided cardiac thrombus to outcomes in patients with acute pulmonary embolism

Atrial fibrillation (AF) can induce a hypercoagulable state in both the left and right atria. Thrombus in the right side of the heart (RHT) may lead to acute pulmonary embolism (APE). The aim of the study was to determine the prevalence of RHT and AF and to assess their impact on outcomes in patients with APE. The retrospective cohort included 1,006 patients (598 female), with a mean age of 66 ± 15 years. The primary end point was all-cause mortality. The secondary end point was incidence of complications (death, cardiogenic shock, cardiac arrest, vasopressor/inotrope treatment, or ventilatory support). Atrial fibrillation was detected in 231 patients (24%). RHT was observed in 50 patients (5%). The combination of AF and RHT was observed in 16 patients (2%). The overall mortality rate was significantly higher in patients with RHT compared with those without (32% vs 14%, respectively, odds ratio [OR] 3.0, 95% confidence interval [CI] 1.6 to 5.6, p = 0.001). The rate of complications was significantly higher in patients with RHT in comparison to those without (40% vs 22%, respectively, OR 2.4, 95% CI 1.3 to 4.4, p = 0.004). The mortality rate in patients with both AF and RHT was significantly higher in comparison to those with AF but without RHT (50% vs 20%, respectively, OR 3.86, 95% CI 1.3 to 11.2, p = 0.01). In multivariate analysis, RHT (p = 0.03) was an independent predictor of death. In conclusion, AF is a frequent co-morbidity in patients with APE, and the presence of RHT is not uncommon. Among patients with APE, the presence of RHT increases the mortality approximately threefold regardless of the presence of known AF.

Temporal trends and patterns in percutaneous treatment of coronary artery disease in Poland in the years 2005-2011

BACKGROUND

According to a recent survey, Poland is one of the leaders of interventional cardiology in Europe in terms of the number of primary percutaneous coronary intervention (PCI) procedures per million inhabitants.

AIM

To present temporal trends in epidemiology, demographics, treatment, and periprocedural outcome of patients referred for percutaneous coronary angiography and angioplasty in Poland in 2005-2011, based on the Polish National PCI Registry.

METHODS

Patients who underwent percutaneous coronary angiography (ANGIO group) and/or angioplasty (PCI group) were included in the Polish National PCI Registry - a prospective observational registry study in Poland.

RESULTS

There were 935,429 patients in the ANGIO group and 501,117 in the PCI group in Poland in 2005-2011. The number of catheterisation labs increased from 75 to 137, angiography procedures rose from 99,195 to 180,935, and PCIs from 50,297 to 99,614. The procedural mortality and stroke rates for the ANGIO group have remained stable whereas for the PCI group procedural mortality has increased over the years. The use of drug eluting stents (DESs) rose from 32.8% to 55.3% in stable angina and the use of a radial approach from 26.8% to 39.1%.

CONCLUSIONS

Use of modern attributes of interventional cardiology like DES stents, radial approach, and treatment of higher risk patients has increased in Poland in 2005-2011. The adoption of the "Stent for Life" initiative has resulted in an increasing number of percutaneous coronary procedures over the years.

Computer-based prediction of the drug proarrhythmic effect: problems, issues, known and suspected challenges

It is likely that computer modelling and simulations will become an element of comprehensive cardiac safety testing. Their role would be primarily the integration and the interpretation of previously gathered data. There are still unanswered questions and issues which we list and describe below. They include sources of data used for the development of the models as well as data utilized as input information, which can come from the in vitro studies and the quantitative structure-activity relationship models. The pharmacokinetics of the drugs in question play a crucial role as their active concentration should be considered, yet the question remains where is the right place to assess it. The pharmacodynamic angle includes complications coming from multiple drugs (i.e. active metabolites) acting in parallel as well as the type of interaction with (potentially) multiple affected channels. Once established, the model and the methodology of its use should be further validated, optimistically against individual data reported at the clinical level as the physiological, anatomical, and genetic parameters play a crucial role in the drug-triggered arrhythmia induction. All the abovementioned issues should be at least considered and-hopefully-resolved, to properly utilize the mathematical models for a cardiac safety assessment.

Model of the distribution of diastolic left ventricular posterior wall thickness in healthy adults and its impact on the behavior of a string of virtual cardiomyocytes

Correlation of the thickness of the left ventricular posterior wall (LVPWd) with various parameters, including age, gender, weight and height, was investigated in this study using regression models. Multicenter derived database comprised over 4,000 healthy individuals. The developed models were further utilized in the in vitro-in vivo (IVIV) translation of the drug cardiac safety data with use of the mathematical model of human cardiomyocytes operating at the virtual healthy population level. LVPWd was assumed to be equivalent to the length of one-dimensional string of virtual cardiomyocyte cells which was presented, as other physiological factors, to be a parameter influencing the simulated pseudo-ECG (pseudoelectrocardiogram), QTcF and ∆QTcF, both native and modified by exemplar drug (disopyramide) after I Kr current disruption. Simulation results support positive correlation between the LVPWd and QTcF/∆QTc. Developed models allow more detailed description of the virtual population and thus inter-individual variability influence on the drug cardiac safety.

Electrocardiographic abnormalities in patients with acute pulmonary embolism complicated by cardiogenic shock

BACKGROUND

Cardiogenic shock (CS) is a predictor of poor prognosis in patients with acute pulmonary embolism (APE).

OBJECTIVES

The aim of this study was to compare electrocardiography (ECG) parameters in patients with APE presenting with or without CS.

METHODS

A 12-lead ECG was recorded on admission at a paper speed of 25 mm/s and 10 mm/mV amplification. All ECGs were examined by a single cardiologist who was blinded to all other clinical data. All ECG measurements were made manually.

RESULTS

Electrocardiographic data from 500 patients with APE were analyzed, including 92 patients with CS. The following ECG parameters were associated with CS: S1Q3T3 sign, (odds ratio [OR]: 2.85, P<.001), qR or QR morphology of QRS in lead V1, (OR: 3.63, P<.001), right bundle branch block (RBBB) (OR: 2.46, P=.004), QRS fragmentation in lead V1 (OR: 2.94, P=.002), low QRS voltage (OR: 3.21, P<.001), negative T waves in leads V2 to V4 (OR: 1.81, P=.011), ST-segment depression in leads V4 to V6 (OR: 3.28, P<.001), ST-segment elevation in lead III (OR: 4.2, P<.001), ST-segment elevation in lead V1 (OR: 6.78, P<.01), and ST-segment elevation in lead aVR (OR: 4.35, P<.01). The multivariate analysis showed that low QRS voltage, RBBB, and ST-segment elevation in lead V1 remained statistically significant predictors of CS.

CONCLUSIONS

In patients with APE, low QRS voltage, RBBB, and ST-segment elevation in lead V1 were associated with CS.

In vitro-in vivo extrapolation of drug-induced proarrhythmia predictions at the population level

Drug cardiotoxicity is a serious issue for patients, regulators, pharmaceutical companies and health service payers because they are all affected by its consequences. Despite the wide range of data they generate, existing approaches for cardiac safety testing might not be adequate and sufficiently cost-effective, probably as a result of the complexity of the problem. For this reason, translational tools (based on biophysically detailed, mathematical models) allowing for in vitro-in vivo extrapolation are gaining increasing interest. This current review describes approaches that can be used for cardiac safety assessment at the population level, by accounting for various sources of variability including kinetics of the compound of interest.

Circadian models of serum potassium, sodium, and calcium concentrations in healthy individuals and their application to cardiac electrophysiology simulations at individual level

In the article a brief description of the biological basis of the regulation of human biological clocks was presented in order to introduce the role of circadian rhythms in physiology and specifically in the pharmacological translational tools based on the computational physiology models to motivate the need to provide models of circadian fluctuation in plasma cations. The main aim of the study was to develop statistical models of the circadian rhythm of potassium, sodium, and calcium concentrations in plasma. The developed ion models were further tested by assessing their influence on QT duration (cardiac endpoint) as simulated by the biophysically detailed models of human left ventricular cardiomyocyte. The main results are model equations along with an electronic supplement to the article that contains a fully functional implementation of all models.

Age and gender dependent heart rate circadian model development and performance verification on the proarrhythmic drug case study

BACKGROUND

There are two main reasons for drug withdrawals at the various levels of the development path - hepatic and cardiac toxicity. The latter one is mainly connected with the proarrhythmic potency and according to the present practice is supposed to be recognized at the pre-clinical (in vitro and animal in vivo) or clinical level (human in vivo studies). There are, although, some limitations to all the above mentioned methods which have led to novel in vitro - in vivo extrapolation methods being introduced. With the use of in silico implemented mathematical and statistical modelling it is possible to translate the in vitro findings into the human in vivo situation at the population level. Human physiology is influenced by many parameters and one of them which needs to be properly accounted for is a heart rate which follows the circadian rhythm. We described such phenomenon statistically which enabled the improved assessment of the drug proarrhythmic potency.

METHODS

A publicly available data set describing the circadian changes of the heart rate of 18 healthy subjects, 5 males (average age 36, range 26-45) and 13 females (average age 34, range 20-50) was used for the heart rate model development. External validation was done with the use of a clinical research database containing heart rate measurements derived from 67 healthy subjects, 34 males and 33 females (average age 33, range 17-72). The developed heart rate model was then incorporated into the ToxComp platform to simulate the impact of circadian variation in the heart rate on QTc interval. The usability of the combined models was assessed with moxifloxacin (MOXI) as a model drug.

RESULTS

The developed heart rate model fitted well, both to the training data set (RMSE = 128 ms and MAPE = 12.3%) and the validation data set (RMSE = 165 ms and MAPE = 17.1%). Simulations performed at the population level proved that the combination of the IVIVE platform and the population variability description allows for the precise prediction of the circadian variation of drugs proarrhythmic effect.

CONCLUSIONS

It can be concluded that a flexible and practically useful model describing the heart rate circadian variation has been developed and its performance was verified.

Changes in the properties of pig manure slurry

The paper presents the results of analyses of samples of manure from a pig farm located near Piła, Poland performed between June 2011 and May 2012 using a single sampling system. The statistical analyses of the average content of chemical and biological oxide demands, nitrogen, phosphorus, potassium, calcium and dry mass in the slurry in various seasons allowed us to draw conclusions concerning the changes in the chemical composition of the manure in specific seasons and to determine the correlations between the chemical parameters. The average content of N, BOD, P, and dry mass content tended to decrease systematically from the spring until the winter. The highest correlation coefficient, which indicates significant interdependency among the variables tested, was consistently found for COD and BOD, whereas the smallest correlation coefficient was found consistently for K and Ca and once for Ca and N.

High tea and vegetable consumption is associated with low ADMA generation in older healthy subjects

Asymmetric dimethylarginine (ADMA) has been recognized as a marker of cardiovascular risk. We sought to investigate whether consumption of tea, coffee, fruit or vegetables is associated with ADMA. In 148 consecutive apparently healthy subjects (104 men and 44 women aged 40 to 70), daily tea, coffee, fruit and vegetable consumption was ascertained by questionnaire. Plasma ADMA, symmetric dimethylarginine (SDMA), and l-arginine levels were measured by high-performance liquid chromatography. Median tea and coffee consumption was 2 cups/d, while vegetable and fruit intake was 152 (120-179)g/d and 120 (108-134)g/d, respectively. Median plasma ADMA, SDMA and arginine were 0.47 (0.43-0.53)μmol/L, 0.59 (0.54-0.66)μmol/L and 86 (68-101)μmol/L, respectively. ADMA correlated inversely with tea (r = -0.70, P < .0001) and vegetable consumption (r = -0.50, P < .0001) even after adjustment for age, sex, body mass index, smoking status, and potential dietary and biochemical parameters. No association between ADMA and fruit consumption was found. ADMA correlated positively with coffee intake (r = 0.37, P < .0001), although these associations were less potent after adjustment for dietary factors. Higher tea and vegetable intake is associated with lower plasma ADMA levels in healthy middle-aged subjects.

Electrocardiographic diagnosis of biventricular pacing in patients with nonapical right ventricular leads

BACKGROUND

Assessment of left ventricular (LV) capture is of paramount importance in patients with biventricular (BiV) pacing. Our goal was to identify electrocardiographic features that differentiate between BiV and right ventricular (RV)-only pacing in patients with nonapical RV leads.

METHODS

The study enrolled 300 consecutive patients with BiV devices and nonapical RV leads, and obtained from them 558 electrocardiograms with either BiV pacing (n = 300) or RV-only pacing (n = 258). RV pacing served as a surrogate for loss of LV capture. Electrocardiograms from the first 150 patients were used to identify BiV-specific features, and to construct an algorithm to differentiate between BiV and RV-only pacing. Electrocardiograms from the second 150 patients were used to validate the algorithm.

RESULTS

The following electrocardiographic features typical of BiV pacing were identified: QS in lead V6 (specificity = 98.7%, sensitivity = 54.7%), dominant R in lead V1 (specificity = 100%, sensitivity = 23.3%), q in lead V6 (specificity = 96%, sensitivity = 22.7%), and a QRS < 160 ms (specificity = 100%, sensitivity = 66.0%). The algorithm based on those features was found to have an overall diagnostic accuracy of 95.0%, a specificity of 96.0%, and a sensitivity of 93.5%.

CONCLUSIONS

The study identified QRS features that were very specific for BiV pacing in patients with nonapical RV leads. Sequential arrangement of those features resulted in an algorithm that was very accurate for differentiating between BiV pacing and loss of LV capture.

Predictive model for L-type channel inhibition: multichannel block in QT prolongation risk assessment

Evaluation of the proarrhythmic potential of an investigated compound is now an integral element of the safety profile required for the approval of new drugs. The human ether-à-go-go-related gene (hERG) channel blocking potency is regarded as a surrogate marker of the proarrhythmic risk at the early stages of the research and development process. However, there is no straight correlation between QT prolongation and TdP occurrence probability, and hERG inhibition potential can be an inadequate predictor of QT prolongation. The L-type calcium channel plays a pivotal role in cardiomyocytes' physiology. Thus the main aim of this study was to develop a predictive model for drug-triggered CaL channel inhibition and also the assessment of drug-multichannel interaction effects on the heart rate-corrected QT interval. The data set, consisting of 123 records describing in vitro experimental settings, measured IC₅₀ values and calculated physico-chemical properties for 72 various chemicals, was collected. The models were tested in a modified 10-fold cross-validation procedure. The generalization ability of the best model was as follows: root mean squared error (RMSE) = 1.10, normalized root mean squared error (NRMSE) = 16.09%. Out of the 10 most important variables, 5 described conditions of the in vitro experiments thus their description and experiment's conditions standardization might be the key to the models better performance. The simulations performed with the ToxComp system showed that the hERG block alone causes concentration-dependent QT prolongation, whereas when multichannel block is regarded, the effect could be reversed. For that reason, the multichannel interaction of tested compounds should be taken into consideration, in order to make the proarrhythmic risk assessment more reliable.

Inter-individual variability in the pre-clinical drug cardiotoxic safety assessment--analysis of the age-cardiomyocytes electric capacitance dependence

Electrical phenomena located within the plasma membrane of the mammalian cardiac cells are connected with the cells' main physiological functions--signals processing and contractility. They were extensively studied and described mathematically in so-called Hodgkin-Huxley paradigm. One of the physiological parameters, namely cell electric capacitance, has not been analyzed in-depth. The aim of the study was to validate the mechanistic model describing the capacitive properties of cells, based on a collected experimental dataset which describes the electric capacitance of human ventricular myocytes. The gathered data was further utilized for developing an empirical correlation between a healthy individual's age and cardiomyocyte electric capacitance.

Virtual population generator for human cardiomyocytes parameters: in silico drug cardiotoxicity assessment

BACKGROUND

The anatomical and histological parameters of the human ventricle depend on many factors including age and sex. Myocyte volume and electric capacitance are significant physiological parameters of left ventricle cardiomyocyte mathematical models. They allow the assessment of inter-individual variability during in vitro-in vivo extrapolation of the drug cardiotoxic effect.

OBJECTIVE

The current research was carried out to analyze the relationship between age, human left ventricle cardiomyocyte volume, and electric capacitance in a healthy population.

METHODS

In order to collect data describing cardiomyocyte volume and membrane area, literature searches were performed. It was assumed that the cardiomyocyte volume (VOL) and area (AREA) distribution have non-negative support and are skewed to the right. A log-linear model with constant variance was used. A simulation study was run to assess the influence of physiological parameters on action potential duration.

RESULTS

The coefficient of determination for the proposed model R(2) = 0.95, that is, 95% of the variability observed in log cardiomyocyte volume can be explained by the estimated regression equation. To allow simple calculation and model performance validation, a simple Excel file was developed (Supplementary material).

CONCLUSIONS

To the best of our knowledge, there is no other model available, combining age, cardiomyocyte volume, and area. The main limitations of the proposed models result from the assumptions made at the data analysis stage. The limited amount of information available in the literature and the lack of differentiation between sexes results in one common equation. The developed model is a part of the computational system for drug cardiotoxicity assessment.

Nɛ-homocysteinyl-lysine isopeptide is associated with progression of peripheral artery disease in patients treated with folic acid

OBJECTIVE

Folic acid (FA) administration can reduce plasma total homocysteine (tHcy); however, it fails to decrease cardiovascular events and progression of peripheral artery disease (PAD). Nɛ-homocysteinyl-lysine isopeptide (Nɛ-Hcy-Lys) is formed during catabolism of homocysteinylated proteins. We sought to investigate factors that determine the presence of Nɛ-Hcy-Lys in PAD patients with hyperhomocysteinemia receiving FA.

PATIENTS AND METHODS

We studied 131 consecutive PAD patients with tHcy > 15 μmol l(-1) taking FA 0.4 mg d(-1) for 12 months. Serum Nɛ-Hcy-Lys was determined by high-performance liquid chromatography (HPLC). We also measured interleukin-6 (IL-6), plasminogen activator inhibitor-1 (PAI-1), asymmetric dimethylarginine (ADMA) and 8-iso-prostaglandin F(2α) (8-iso-PGF(2α)).

RESULTS

FA administration resulted in a 70.5% decrease in tHcy (p < 0.0001). However, serum Nɛ-Hcy-Lys was detectable in 28 (21.4%) patients on FA who were more frequently current smokers and survivors of ischaemic stroke (p < 0.001). They had higher tHcy by 46.0%, PAI-1 by 51.7%, 8-iso-PGF(2α) by 59.1% and ADMA by 26.4% (all, p < 0.0001). The presence of Nɛ-Hcy-Lys was associated with lower ankle-brachial index (ABI) values (p < 0.001) and higher prevalence of cardiovascular events (p < 0.001) following therapy.

CONCLUSION

The presence of Nɛ-Hcy-Lys in one-fifth of hyperhomocysteinemic individuals with PAD despite FA treatment is associated with progression of PAD and with increased ADMA formation, oxidative stress and hypofibrinolysis.

Slow delayed rectifying potassium current (IKs ) - analysis of the in vitro inhibition data and predictive model development

The excitable cell membranes contain ion channels that allow the ions passage through the specific pores via a passive process. Assessment of the inhibition of the IKr (hERG) current is considered to be the main target during the drug development process, although there are other ionic currents for which drug-triggered modification can either potentiate or mask hERG channel blockade. Information describing the results of in vitro studies investigating the chemical-IKs current interactions has been developed in the current study. Based on the publicly available data sources, 145 records were collected. The final list of publications consists of 64 positions and refers to 106 different molecules connected with IKs current inhibition, with at least one IC50 value measured. Ultimately, 98 of the IC50 values expressed as absolute values were gathered. For 36 records the IC50 was expressed as a relative value. For the 11 remaining records, the inhibition was not clearly expressed. Based on the collected data the predictive models for the IC50 estimation were developed with the use of various algorithms. The extended Quantitative Structure-Activity Relationships (QSAR) methodology was applied and the in vitro research settings were included as independent variables, apart from the physico-chemical descriptors calculated with the use of the Marvin Calculator Plugins. The root mean squared error and normalized root mean squared error values for the best model (an expert system based on two independent artificial neural networks) were 0.86 and 14.04%, respectively. The model was further built into the ToxComp system, the ToxIVIVE tool specialized for cardiotoxicity assessment of drugs.

BDTcomparator: a program for comparing binary classifiers

SUMMARY

The BDTcomparator facilitates the selection of the best performing binary classification model or binary diagnostic procedure from the many possible alternatives by comparing their predictions with a known output, measured with the use of a system recognized as the gold standard. The program calculates the estimates of accuracy, sensitivity, specificity, predictive values and diagnostic likelihood ratios along with appropriate confidence intervals. Furthermore, all pairwise comparisons with respect to the above-mentioned measures are calculated. The formatted results can be exported to a text-file.

AVAILABILITY AND IMPLEMENTATION

BDTcomparator is distributed under the GNU GPLv3 license and is freely available for download from http://www.tox-portal.net. We provide programs for both Linux and Windows operating systems. The source code of the program is provided in our companion website http://code.google.com/p/bdtcomparator/.

CONTACT

kamil.fijorek@uek.krakow.pl

SUPPLEMENTARY INFORMATION

Supplementary data are available at Bioinformatics online.

The open-access dataset for insilico cardiotoxicity prediction system

Drug cardiotoxicity is one of the main reasons of fatal drug related problem events and the subsequent withdrawals. Therefore, its early assessment is a crucial element of the drug development process. For the drug driven hERG inhibition assessment, which is assumed to be the main reason for toxicity, in vitro techniques are used. Gold standards are based on the Patch Clamp method with the use of various cell models but due to its low throughput, insilico models have become more appreciated. To develop a reliable empirical QSAR model, wide dataset containing a variety of cases has to be available. In this article, a freely available for download, set of data is described. It is based on literature peer-reviewed reports and contains hERG inhibition information expressed as IC50 value for 263 molecules described in 642 records. All studies were done with the use of three cell models (XO, CHO, HEK) and other elements describe the electrophysiological settings of the in vitro study. The above mentioned set was used for the successful development of the predictive models.