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.

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.

Cardiac resynchronization therapy-induced acute shortening of QRS duration predicts long-term mortality only in patients with left bundle branch block.

AIMS: QRS narrowing with initiation of biventricular pacing might be an acute electrocardiographic indicator of correction of left bundle branch block (LBBB)-induced depolarization delay and asynchrony. However, its impact on prognosis remains controversial, especially in non-LBBB patients. Our goal was to evaluate the impact of QRS narrowing on long-term mortality and morbidity in a large cohort of patients undergoing cardiac resynchronization therapy (CRT) with different pre-implantation QRS types: LBBB, non-LBBB, and permanent right ventricular pacing. METHODS AND RESULTS: This study included consecutive patients who underwent CRT device implantation. Study endpoints: death from any cause or urgent heart transplantation and death from any cause/urgent heart transplantation or hospital admission for heart failure. All pre- and post-implantation electrocardiograms were analysed using digital callipers, high-amplitude augmentation, 100 mm/s paper speed, and global QRS duration measurement method. A total of 552 CRT patients entered the survival analysis. During the 9 years observation period, 232 (42.0%) and 292 (52.9%) patients met primary and secondary endpoints, respectively. QRS narrowing predicted survival in the Kaplan-Meier analysis only in patients with LBBB. Multivariate Cox regression model showed that QRS narrowing was the major determinant of both study endpoints, with hazard ratios of 0.46 and 0.43, respectively. There was a strong relationship between mortality risk and shortening/widening of the QRS, albeit only in the LBBB group. Patients with non-LBBB morphologies had unfavourable prognosis similar to that in LBBB patients without QRS narrowing. CONCLUSION: Acute QRS narrowing in patients with LBBB might be a desirable endpoint of CRT device implantation.

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.

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.

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.

New ECG markers for predicting long-term mortality and morbidity in patients receiving cardiac resynchronization therapy.

We investigated prognostic value of four recently proposed ECG markers in patients with cardiac resynchronization therapy (CRT): 1./ pathological preimplantation QRS axis, 2./ increase in QRS amplitude in V3 during biventricular pacing, 3./ negative QRS in V1/V2 during left ventricular (LV)-only pacing, 4./ longer QRS duration during LV-only pacing. A longitudinal cohort study was performed (n = 552). RESULTS: During the 9-year observation period the primary endpoint (death from any cause or urgent heart transplantation) was met in 232 patients. The secondary endpoint of survival free of heart failure hospitalization was met in 292 patients. Long LV-paced QRS and pathological axis predicted unfavorable prognosis in Kaplan-Meier analysis. In multivariable Cox model (functional class, LV ejection fraction, LV end-diastolic dimension, permanent atrial fibrillation, age, gender, heart failure etiology, creatinine level, diabetes mellitus), LV-paced QRS duration remained a significant determinant of both endpoints. The other studied ECG markers lacked independent prognostic value.

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.

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.

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.

The ventricular tachycardia score: a novel approach to electrocardiographic diagnosis of ventricular tachycardia.

AIMS: Electrocardiographic diagnosis of wide QRS complex tachycardia (WCT) continues to be challenging as none one of the available methods is specific for ventricular tachycardia (VT) diagnosis. We aimed to construct a method for WCT differentiation based on a scoring system, in which ECGs are graded according to the number of VT-specific features. This novel method was validated and compared with Brugada algorithm and other methods. METHODS AND RESULTS: A total of 786 WCTs (512 VTs) from 587 consecutive patients with a proven diagnosis were analysed by two blinded observers. The VT score method was based on seven ECG features: initial R wave in V1, initial r > 40 ms in V1/V2, notched S in V1, initial R in aVR, lead II R wave peak time ≥50 ms, no RS in V1-V6, and atrioventricular dissociation. Atrioventricular dissociation was assigned two points, and each of the other features was assigned one point. The overall accuracy of VT score ≥1 for VT diagnosis (83%) was higher than that of the aVR (72%, P = 0.001) and Brugada (81%) algorithms. Ventricular tachycardia score ≥3 was present in 66% of VTs and was more specific (99.6%) than any other algorithm/criterion for VT diagnosis. Ventricular tachycardia score ≥4 was present in 33% of VTs and was 100% specific for VT. CONCLUSION: The new ECG-based method provides a certain diagnosis of VT in the majority of patients with VT, identifies unequivocal ECGs, and has superior overall diagnostic accuracy to other ECG methods.

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.

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.

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.

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.

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.

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.

Universal algorithm for diagnosis of biventricular capture in patients with cardiac resynchronization therapy.

BACKGROUND: An accurate and universal method for diagnosis of biventricular (BiV) capture using a standard 12-lead electrocardiogram (ECG) would be useful for assessment of cardiac resynchronization therapy (CRT) patients. Our objective was to develop and validate such an ECG method for BiV capture diagnosis that would be independent of pacing lead positions-a major confounder that significantly influences the morphologies of paced QRS complexes. METHODS: On the basis of an evaluation of 789 ECGs of 443 patients with heart failure and various right ventricular (RV) and left ventricular (LV) lead positions, the following algorithm was constructed and validated. BiV capture was diagnosed if the QRS in lead I was predominantly negative and either V1 QRS was predominantly positive or V6 QRS was of negative onset and predominantly negative (step 1), or if QRS complex duration was <160 ms (step 2). All other ECGs were classified as loss of LV capture. RESULTS: The algorithm showed good accuracy (93%), sensitivity (97%), and specificity (90%) for detection of loss of LV capture. The performance of the algorithm did not differ among apical, midseptal, and outflow tract RV lead positions and various LV lead positions. CONCLUSION: LV capture leaves diagnostic hallmarks in the fused BiV QRS related to different vectors of depolarization and more rapid depolarization of the ventricles. An accurate two-step ECG algorithm for BiV capture diagnosis was developed and validated. This algorithm is universally applicable to all CRT patients, regardless of the positions of the pacing leads.

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.

Use of ischemic ECG patterns for risk stratification in intermediate-risk patients with acute PE.

BACKGROUND: European recommendations on the management of acute pulmonary embolism (APE) divide patients into 3 risk categories: high, intermediate, and low. Mortality has previously been estimated at 3% to 15% in the intermediate group. The aim of this study was to use a new metric "ischemic electrocardiographic (ECG) patterns" to more precisely estimate the risk (complications or death) of APE patients identified as "intermediate risk" by current European Society of Cardiology (ESC) criteria. METHODS: The study group consisted of 500 consecutive patients (290 females), with a mean age 66.3 ± 15.2 years, and 245 (72.8%) patients were initially classified as intermediate risk. Four ischemic ECG patterns were studied: (i) ST-segment ischemic pattern (STIP), (ii) global ischemic pattern (GIP), (iii) negative T wave pattern, and (iv) control group consisting of patients with no ischemic changes. RESULTS: Predictors of death in univariate analysis included elevated troponin concentration (odds ratio [OR], 6.8; 95% confidence interval [CI], 1.28-169; P = 0.02]) and ischemic ECG patterns: STIP (OR, 6.3; 95% CI, 1.6-46.0; P = 0.007). Patients with right ventricular dysfunction (RVD) who were STIP (+) experienced significantly higher mortality rate compared to RVD patients who were STIP(-) (11.4% vs 1.6%; OR, 7.26; 95% CI, 1.82-52.8; P = 0.004). In patients with STIP (+) as compared to STIP (-), rate of death (OR, 6.35; P = 0.007) and rate of complications (OR, 4.19; P = 0.002) were significantly higher. Neither presence of negative T-waves nor GIP pattern was associated with a worse prognosis. CONCLUSIONS: In patients with APE, an ischemic ECG pattern on hospital admission, when identified in addition to classic risk markers, is an independent risk factor for worse in-hospital outcomes.