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Background: Increasing utilization of long-term outpatient ambulatory electrocardiographic (ECG) monitoring continues to drive the need for improved ECG interpretation algorithms., Objective: The purpose of this study was to describe the BeatLogic® platform for ECG interpretation and to validate the platform using electrophysiologist-adjudicated real-world data and publicly available validation data., Methods: Deep learning models were trained to perform beat and rhythm detection/classification using ECGs collected with the Preventice BodyGuardian® Heart monitor. Training annotations were created by certified ECG technicians, and validation annotations were adjudicated by a team of board-certified electrophysiologists. Deep learning model classification results were used to generate contiguous annotation results, and performance was assessed in accordance with the EC57 standard., Results: On the real-world validation dataset, BeatLogic beat detection sensitivity and positive predictive value were 99.84% and 99.78%, respectively. Ventricular ectopic beat classification sensitivity and positive predictive value were 89.4% and 97.8%, respectively. Episode and duration F 1 scores (range 0-100) exceeded 70 for all 14 rhythms (including noise) that were evaluated. F 1 scores for 11 rhythms exceeded 80, 7 exceeded 90, and 5 including atrial fibrillation/flutter, ventricular tachycardia, ventricular bigeminy, ventricular trigeminy, and third-degree heart block exceeded 95., Conclusion: The BeatLogic platform represents the next stage of advancement for algorithmic ECG interpretation. This comprehensive platform performs beat detection, beat classification, and rhythm detection/classification with greatly improved performance over the current state of the art, with comparable or improved performance over previously published algorithms that can accomplish only 1 of these 3 tasks., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: The deterioration of left atrial and ventricular functions was demonstrated in patients with frequent ventricular extrasystole (fVES). The exact pathophysiology of left atrial dysfunction in patients with fVES is unclear. Retrograde ventriculoatrial conduction (VAC) often accompanies fVES, which may contribute to atrial dysfunction. We investigated whether atrial electromechanical delay and VAC are related to these atrial functions in patients with frequent right ventricular outflow tract (RVOT) VES and preserved ejection fraction (pEF)., Methods: This study included 21 patients with pEF (eight males, 48 ± 11 years), who had experienced more than 10 000 RVOT-VES during 24-h Holter monitoring and had undergone electrophysiological study/ablation. The study also included 20 healthy age- and sex-matched control subjects. Transthoracic echocardiography was performed on all of the subjects. Atrial conduction time was obtained by using tissue Doppler imaging. Strain analysis was performed with two-dimensional speckle tracking echocardiography., Results: The peak atrial longitudinal strain was significantly impaired in patients with fVES (P = 0.01). In addition, although the interatrial and left atrial conduction delay times were significantly different between each group (P < 0.001, P < 0.001), the right atrial conduction delay times were similar. When patients with fVES were divided into groups depending on the existence of retrograde VAC, atrial deformation parameters and conduction delay time did not significantly differ between either group., Conclusion: Frequent RVOT-VES causes left atrial dysfunction. This information is obtained through strain analyses and recordings of left atrial conduction times in patients with pEF. Regardless, retrograde VAC is not related to atrial dysfunction., (© 2019 Wiley Periodicals, Inc.)

Premature complexes are electrical impulses arising from atrial, junctional, or ventricular tissue, leading to premature heart beats. Premature atrial beats are much more frequent than those arising in the atrioventricular junction but less frequent than premature beats from the ventricles. Although they are usually benign and highly prevalent in the general population, they could trigger sustained supraventricular and ventricular arrhythmias, and cause cardiomyopathies. The aim of this article was to review the main electrocardiology features of premature complexes and discuss their implications in clinical practice., (Copyright © 2018 Elsevier Inc. All rights reserved.)

In a woman with syncope, junctional premature complexes and what appeared to be intermittent atrioventricular block suggested concealed conduction of His bundle extrasystoles., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Double ventricular response in dual atrioventricular (AV) nodal pathways can result in nonreentrant supraventricular tachycardia. Since this condition was first described in 1979, around 20 cases have been reported. Here, we present the case of a patient with a confirmed diagnosis of double ventricular response in dual AV nodal pathways resembling an interpolated premature beat who underwent successful radiofrequency ablation of the slow pathway.

Background: Differentiation of atrial fibrillation (AF) trigger ectopy from other ectopy is often difficult. The purpose of this study was to compare the origin and coupling intervals (CI) between AF-trigger and non-AF-trigger ectopy., Methods: This study consisted of 120 patients with AF who underwent an initial ablation. Isoproterenol was infused up to 20μg/min to provoke ectopy and AF. We measured the CI of all ectopy provoked by an isoproterenol infusion. The %CI was calculated as the CI of the ectopy/P-P interval of the preceding 2 beats., Results: A total of 117 patients had at least one ectopy, and AF was induced in 56 (47%) patients. Of the 276 ectopies observed in this study, 211 (76%) originated from pulmonary veins and 77 (28%) were AF-trigger ectopy. AF-trigger ectopy more frequently originated from pulmonary veins (PVs) (74 vs. 3, p<0.001) and had a significantly shorter CI (201±70ms vs. 365±147ms, p<0.001) and lower %CI (29±11% vs. 55±14%, p<0.001) than that of non-AF-trigger ectopy. A receiver operating characteristics analysis revealed that a %CI of 40% was the best cut-off value for differentiating whether it was an AF-trigger or not. The identified trigger group, including patients with provoked AF-trigger ectopy or ectopy with a low %CI (<40%), had a significantly better AF recurrence-free survival rate than the other group (88% vs. 65%, p=0.004)., Conclusions: AF-trigger ectopy predominantly originated from PVs and had a short CI. These findings may be useful for estimating whether ectopies are an AF-trigger or not., (Copyright © 2017 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.)

Background: Coronary computed tomography angiography (coronary CTA) provides non-invasive evaluation of the coronary arteries with high precision for the detection of significant coronary artery disease (CAD)., Aim: To investigate whether irregular heart rhythm including atrial fibrillation and premature beats during data acquisition influences (i) radiation and contrast media exposure, (ii) number of non-evaluable coronary segments and (iii) diagnostic impact of coronary CTA., Methods: Twelve tertiary care centers with ≥64 slice CT scanners and ≥5 years of experience with cardiovascular imaging participated in this registry. Between 2009 and 2014, 4339 examinations were analysed in patients who underwent clinically indicated coronary CTA for suspected CAD. Clinical and epidemiologic data were gathered from all patients. In addition, clinical presentation, heart rate and rhythm during the scan, Agatston score, radiation and contrast media exposure and the diagnostic impact of coronary CTA were systematically analysed., Results: Of 4339 patients in total, 260 (6.0%) had irregular heart rhythm, whereas the remaining 4079 (94.0%) had stable sinus rhythm. Patients with irregular heart rhythm were older (63.2 ± 12.5yrs versus 58.6 ± 11.4yrs. p < 0.001), exhibited a higher rate of pathologic stress tests before CTA (37.1% versus 26.1%, p < 0.01) and higher heart rates during CTA compared to those with sinus rhythm (62.5 ± 11.6bpm versus 58.9 ± 8.5bpm, p < 0.001). Both contrast media exposure and radiation exposure were significantly higher in patients with irregular heart rhythm (90 mL (95%CI = 80-110 mL) versus 80 mL (95%CI = 70-90 mL) and 6.2 mSv (95%CI = 2.5-11.7) versus 3.3 mSv (95%CI = 1.7-6.9), p < 0.001 for both). Coronary CTA excluded significant CAD less frequently in patients with irregular heart rhythm (32.9% versus 44.8%, p < 0.001). This was attributed to the higher rate of examinations with at least one non-diagnostic coronary segment in patients with irregular heart rhythm (10.8% versus 4.6%, p < 0.001). Subsequent invasive angiography could be avoided in 47.2% of patients with irregular heart rhythm compared to 52.9% of patients with sinus rhythm (p = NS), whereas downstream stress testing was recommended in 3.2% of patients with irregular heart rhythm versus 4.0% of patients with sinus rhythm (p = NS)., Conclusion: A significant number of patients scheduled for coronary CTA have irregular heart rhythm in a real-world clinical setting. In such patients, heart rate during coronary CTA is higher, possibly resulting in (i) higher radiation and contrast agent exposure and (ii) more frequent coronary CTA examinations with at least one non-diagnostic coronary artery segment. However, this does not seem to lead to increased downstream stress testing or subsequent invasive procedures., (Copyright © 2018 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.)

Purpose: During cardiac mapping, it is critical to discriminate signals related to cardiac conduction versus those due to mechanical interaction with other cardiac structures such as valves. We sought to define characteristics that could facilitate discrimination of valve artifact from cardiac conduction signals., Methods: Patients with structurally normal heart undergoing mapping for ventricular arrhythmias arising from the vicinity of the aortic valve between January 2013 and May 2015 were included. Potentials felt to reflect aortic valve opening (occurring at the end of the QRS after the local ventricular signal) were termed A1, and those felt to reflect valve closure were termed A2., Results: A total of 24 patients had mapping in the sinuses of Valsalva, and 10 (average age 40 + 15, 60% male) were found to have additional signals (A1 and/or A2) notable during mapping. In all patients, intervals between A1 and A2 shortened after ectopic beats and lengthened after compensatory pauses. These variations in the interval matched the change in systolic duration on Doppler echocardiography. Overdrive atrial pacing was performed in four patients, which demonstrated progressive shortening of intervals between A1 and A2. Pacing always revealed local capture without affecting A1 or A2. In the one patient in whom ablation was performed in these areas, there was no effect on A1 or A2, suggesting these signals represented artifact., Conclusions: Valve-related signals in the aortic sinuses are commonly seen and can be distinguished. The interval between A1 and A2 correlated with mechanical systole and varied in a physiologically predictable manner with heart rate changes.

Introduction: The superior vena cava (SVC) is a main source of nonpulmonary vein (PV) ectopies initiating atrial fibrillation (AF). Empiric SVC isolation may improve rhythm outcomes after catheter ablation of AF. Because the SVC passes immediately adjacent to the right superior PV (RSPV), an electrophysiological relation could be present between the two structures. The present study aimed to estimate the interrelation between the SVC and RSPV by evaluating arrhythmogenic activities observed during catheter ablation of AF., Methods and Results: Study subjects comprised 121 consecutive patients referred for catheter ablation of paroxysmal AF. Isoproterenol infusion was used to induce ectopies and AF. Patients were divided into two groups depending on the presence of arrhythmogenic SVC: arrhythmogenic-SVC (A-SVC) and nonarrhythmogenic SVC (Non-A-SVC) groups. The prevalence of females was higher and body surface area was smaller in the A-SVC group (N = 22) than Non-A-SVC group (N = 99). Arrhythmogenic activities were observed in 60 (49%) RSPVs, 24 (20%) right inferior PVs, 72 (59%) left superior PVs, and 31 (25%) left inferior PVs. Arrhythmogenic RSPVs were more prevalent in the A-SVC group than Non-A-SVC group (86% vs. 41%, P = 0.0001), whereas these prevalences in the other three PVs were not different between groups (P >0.3). In multivariable analysis, arrhythmogenic RSPV was the only independent predictor of arrhythmogenicity of the SVC (OR, 8.53; 95% CI 2.31-31.46; P = 0.001)., Conclusions: An electrophysiological interrelation may be present between the SVC and RSPV in patients with paroxysmal AF. Semiempiric SVC isolation limited to patients with an arrhythmogenic RSPV may be a more efficient treatment strategy., (© 2017 Wiley Periodicals, Inc.)

Introduction: The electrophysiologic mechanism for rate-dependent PVBs associated with double potentials (DPs) was investigated in infarcted canine hearts using bipolar and intracellular microelectrode recordings., Methods and Results: Dogs exhibiting rate-related ventricular ectopic beats (coupling interval, 390 ± 54 milliseconds) during sinus rhythm or atrial pacing were studied 4-5 days (N = 63) or 25 days (N = 16) following anterior descending coronary artery ligation. Sites of DP and rate-dependent arrhythmia formation were identified in vivo using bipolar recordings for subsequent ex vivo studies. Rate-dependent conduction delays with increasing duration isoelectric intervals representing very slow conduction were observed at sites of DP formation, frequently provoking both manifest and concealed reentry (non-stimulated beats) over a narrow range of paced cycle lengths. Both slow antegrade and retrograde activation across an inexcitable gap (reflection) were integral components of extrasystole formation. Retrograde reflection to a region of very slow conduction (mid-potential) during antegrade activation was routinely observed at 4-5 days (42 of 63 preparations, 67%) and 25 days (22 of 26 preparations, 85%) postcoronary artery ligation. Reflection and premature re-activation of the proximal site was then observed in 6 of 63 (9%), and 3 of 26 preparations (12%)., Conclusion: The present experiments demonstrate DP formation and rate-dependent constant-coupled late epicardial premature beats in infarcted dog hearts. Microelectrode recordings at DP sites demonstrating prolonged isoelectric intervals display very slow conduction preceding distal activation and "reentrant" re-activation of more proximal sites, representing reflection as an arrhythmia mechanism in ischemically injured epicardium during subacute myocardial infarction., (© 2017 Wiley Periodicals, Inc.)

Hypertrophied hearts are known for increased risk of arrhythmias and are linked with reduced ischemic tolerance. However, still little is known about state characterized only by increased left ventricle (LV) mass fraction. Seventeen isolated rabbit hearts with various LV mass were divided into two groups according to LV weight/heart weight ratio (LVW/HW ratio), namely group H and L (with higher and lower LVW/HW ratio, respectively) and underwent three short cycles of global ischemia and reperfusion. The differences in electrogram (heart rate, QRS(max), mean number, onset and dominant form of ventricular premature beats) and in biochemical markers of myocardial injury (creatine kinase, lactate dehydrogenase - LDH) and lipid peroxidation (4-hydroxy-2-nonenal - 4-HNE) were studied. As compared to group L, hearts in group H exhibited lower tolerance to ischemia expressed as higher incidence and severity of arrhythmias in the first ischemic period as well as increase of LDH and 4-HNE after the first reperfusion. In the third cycle of ischemia-reperfusion, the preconditioning effect was observed in both electrophysiological parameters and LDH release in group H. Our results showed consistent trends when comparing changes in electrograms and biochemical markers. Moreover, 4-HNE seems to be good potential parameter of moderate membrane alteration following ischemia-reperfusion injury.

A 32-year-old, otherwise healthy woman was admitted after successful out-of-hospital resuscitation due to ventricular fibrillation. Established cardiac, pulmonary, metabolic, and toxicological causes were excluded. However, persisting (biphasic) negative T waves in the inferior ECG leads and premature ventricular contractions (PVC) were noted. PVC morphology indicated a focus alternating between the posterior papillary muscle/the left posterior fascicle and the left ventricular outflow tract region/anterior papillary muscle. Echocardiography revealed a bileaflet mitral prolapse with mild mitral valve regurgitation. This case is a typical presentation of the recently described malignant bileaflet mitral valve prolapse syndrome. The patient was discharged without overt neurological deficit after implantation of a cardioverter-defibrillator.

Background: The underwater environment presents physiological challenges for the cardiovascular, renal and pulmonary systems. Increases in external hydrostatic pressure reduce the capacity of the venous compartment and cause blood to move toward the lung. The aim of this study was to evaluate retrospectively electrocardiographic (ECG) changes in a cohort of professional divers., Methods: Between January 2009 and January 2012, 225 randomly selected professional divers, 204 male (91%) and 21 female (9%) attended our clinic for their biannual diving medical assessment. Their ECG records were evaluated retrospectively., Results: The most common ECG abnormality observed was incomplete right bundle branch block (IRBBB) in 30 divers (13.3%). Eleven divers (4.9%) showed right QRS axis deviation (seven with IRBBB). Six divers had a sinus tachycardia; in four divers there was early repolarization; three divers had ventricular extrasystoles; one diver had ST elevation in lead V3; there was one with sinus arrhythmia and another with T-wave inversion in leads V2, V3 and aVF. These ECG changes were evaluated retrospectively by a cardiologist who made various recommendations for further review including bubble contrast echocardiography for IRBBB., Conclusions: No serious ECG abnormalities were identified, but IRBBB should be further investigated because of its association with persistent (patent) foramen ovale. Rapid cardiological review of ECGs could be achieved using modern communications technology, such as telecardiography, and further clinical investigations directed by specialist recommendation arranged promptly if indicated.

Hisian extrasystoles originate from the His bundle. They are rare and usually misdiagnosed. In fact, they manifest on the EKG, with a p' wave located before, in or after the QRS complex. More rarely, the extrasystole blocks the propagation of the influx to the ventricles simulating a Mobitz II atrioventricular (AV) block. We report the case of a 36-Year-old woman with no medical History, suffering from presyncope and palpitations at rest. Her physical examination and EKG were normal. The 24-hour Holter monitoring showed some long periods with unexpected blocked p waves but with no significant pause. Considering her young age and the absence of causes of AV block, we performed an intracardiac electrophysiological study which showed hisian extrasystoles with normal conduction tissue properties at baseline and under flecainide. The diagnosis of hisian extrasystoles simulating Mobitz II AV block was made. A simple monitoring with beta-blockers therapy was recommended. Hisian extrasystoles may simulate first or second degree AV block with different therapeutic and prognostic implications. Nevertheless, these hisian extrasystoles may be the marker of a vulnerable AV conduction, long-term follow up should be considered.

Extrasystoles lead to several consequences, ranging from uneventful palpitations to lethal ventricular arrhythmias, in the presence of pathologies, such as myocardial ischemia. The role of working versus conducting cardiomyocytes, as well as the tissue requirements (minimal cell number) for the generation of extrasystoles, and the properties leading ectopies to become arrhythmia triggers (topology), in the normal and diseased heart, have not been determined directly in vivo. Here, we used optogenetics in transgenic mice expressing ChannelRhodopsin-2 selectively in either cardiomyocytes or the conduction system to achieve cell type-specific, noninvasive control of heart activity with high spatial and temporal resolution. By combining measurement of optogenetic tissue activation in vivo and epicardial voltage mapping in Langendorff-perfused hearts, we demonstrated that focal ectopies require, in the normal mouse heart, the simultaneous depolarization of at least 1,300-1,800 working cardiomyocytes or 90-160 Purkinje fibers. The optogenetic assay identified specific areas in the heart that were highly susceptible to forming extrasystolic foci, and such properties were correlated to the local organization of the Purkinje fiber network, which was imaged in three dimensions using optical projection tomography. Interestingly, during the acute phase of myocardial ischemia, focal ectopies arising from this location, and including both Purkinje fibers and the surrounding working cardiomyocytes, have the highest propensity to trigger sustained arrhythmias. In conclusion, we used cell-specific optogenetics to determine with high spatial resolution and cell type specificity the requirements for the generation of extrasystoles and the factors causing ectopies to be arrhythmia triggers during myocardial ischemia.

Aim: To determine the impact of infarct localization and types of reperfusion therapy on the frequency of ventricular premature beats (VPBs) in patients with acute myocardial infarction (AMI) and reduced left ventricular ejection fraction (LVEF)., Methods: A total of 705 patients with acute ST elevation myocardial infarction (STEMI) were divided according to the infarct localization (anteroseptal, anterolateral, inferior and posterior) and reperfusion therapy (fibrinolysis or percutaneous coronary intervention with stenting) into two groups: LVEF<45% was an experimental group and LVEF>45% was a control group. The occurrence of VPBs<10 per hour was defined as a non-significant, and the occurrence of VPBs>10 per hour defined as a significant., Results: In patients with fibrinolysis therapy and LVEF<45% significant number of VPBs were in anteroseptal (p=0.017), anterolateral (p<0.001) and posterior AMI (p<0.001), but in patients with percutaneous coronary intervention (PCI) and LVEF<45% significant number of VPBs were only in anteroseptal AMI (p=0.001) localization., Conclusion: In patients with reduced ejection fraction in AMI, treatment with PCI method has a better antiarrhythmic effect compared to fibrinolysis treatment., (Copyright© by the Medical Assotiation of Zenica-Doboj Canton.)

This paper introduces a novel arterial blood pressure (ABP) signal model that generates statistically accurate synthetic signals with known characteristics. Using parameter identification from real ABP signals to form base parameter templates, our model applies stochastic processes to modulate cardiac cycle period and shape. A real-time control component modulates model parameters between cycle boundaries to emulate properties of real cardiovascular signals, such as arrhythmia, ectopic beats, resonances in the heart-rate variability spectrum, and respiratory cycle modulation of ABP signal amplitude. We present several examples to illustrate the capability of the proposed model.

The ventricular action potential duration (APD) is a fundamental determinant of cardiac electrical stability and can be estimated by measuring the activation recovery interval (ARI) from the unipolar electrogram (UEG), which represents the electrical activity of the heart at the tissue level. Under experimental conditions, automatic estimation of ARIs is challenging due to non-related interferences and low signal-to-noise ratios (SNRs). In this simulation study, we investigated how the reliability of ARI estimates is affected by noise and artefacts in the UEG. Real-like electrograms were generated using a 257-node whole heart model to synthesize 20 real-like UEGs exhibiting constant and dynamic ARI patterns. Controlled degrees of noise and contamination (ectopic beats) were added to obtain a range of signal qualities. The generated recordings were automatically analyzed using a proposed standard method to estimate the ARI. The performance was compared with two improvements of the standard method including a narrow search window and a correlation filter. The results show that the robustness of automatic ARI analysis was dramatically improved by using the proposed improvement methods. For typical recordings with a SNR of 10dB and filtered with often used cutoff frequency of 30Hz to measure repolarization, the average mean absolute error of the estimations was reduced from 16.2ms (range:12.2-29.0ms) for the standard method to 11.6ms (range:6.0-13.4ms) for the improved method. The standard deviation was reduced from 38.2ms (range:26.8- 58.5ms) to 14.6ms (range:7.6-16.9ms). Detection of cyclical variation of ARI was also improved by using the improvement strategy: for 0.2Hz ARI oscillations with an amplitude of 5ms, the highest average detection rate increased from 41% for the standard method to 100% using the improved method for recordings with a SNR of 10dB.

Background: Postextrasystolic blood pressure potentiation (PESP), the pulse wave augmentation after an extrasystolic beat, is typically enhanced in heart failure (HF) patients. This study prospectively tested the association of PESP and mortality in cardiac patients., Methods and Results: Consecutive patients (n=941; mean age, 61 years; 19% female) presenting with acute myocardial infarction were enrolled between May 2000 and March 2005 and followed up until August 2010. The main study outcome was 5-year all-cause mortality. Patients underwent noninvasive 30-minute recordings of ECG and continuous blood pressure. PESP presence was based on the ratio between the first postectopic pulse wave amplitude and the mean of the subsequent 9 pulse wave amplitudes. A ratio above 1 was prospectively defined as PESP present. Ventricular premature complexes (VPCs) suitable for PESP quantification were present in recordings of 220 patients. PESP was present in 62 of these patients. Patients without suitable VPCs were classified as PESP absent.During the follow-up, 72 patients died. Among the 220 patients in whom PESP was measurable, 27 died. Under univariable analysis, PESP was a significant predictor of death (P<0.001) as were GRACE score (P<0.001), left ventricular ejection fraction (LVEF) (P<0.001), and the number of recorded VPCs (P<0.001). Under multivariable analysis, PESP (P<0.001), GRACE score (P<0.001), and LVEF (P=0.001) were independently associated with outcome. The combination of PESP presence and LVEF ≤ 35% identified a subgroup of patients with a particularly high mortality of 46.7%. Separate validation reproduced the finding in an unrelated population of 146 HF patients., Conclusions: PESP, which likely reflects abnormalities of myocardial calcium cycling, predicts the mortality risk in postinfarction patients., Clinical Trial Registration Url: ClinicalTrials.gov. Unique identifier: NCT00196274., (© 2014 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.)

Intermittent high intensity ultrasound scanning with contrast microbubbles can induce scattered cavitation microlesions in the myocardium, which may be of value for tissue reduction therapy. Anesthetized rats were treated in a heated water bath with 1.5 MHz focused ultrasound pulses, guided by an 8 MHz imaging transducer. The relative efficacy with 2 or 4 MPa pulses, 1:4 or 1:8 trigger intervals and 5 or 10 cycle pulses was explored in six groups. Electrocardiogram premature complexes (PCs) induced by the triggered pulse bursts were counted, and Evans blue stained cardiomyocyte scores (SCSs) were obtained. The increase from 2 to 4 MPa produced significant increases in PCs and SCSs and eliminated an anticipated decline in the rate of PC induction with time, which might hinder therapeutic efficacy. Increased intervals and pulse durations did not yield significant increases in the effects. The results suggest that cavitation microlesion production can be refined and potentially lead to a clinically robust therapeutic method., (Copyright © 2014 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.)

Unlabelled: Heart rhythm disorders occupy a leading place in the modern structure of cardiovascular diseases in the children. At present, the role of stress-induced reactions in the development of more than a thousand diseases has been proved. Rehabilitation of systemic manifestations of extrasystolic arrhythmia (EA) in the children is only scarcely described in the literature., Aim: The objective of the present work was to improve the effectiveness of the spa and resort-based treatment of the children presenting with extrasystolic arrhythmia taking advantage of the available information about the different biorhythmic activities of the stress-realizing and stress-limiting systems., Material and Methods: The study included 60 children presenting with EA, who received a standard combination of spa and resort-based therapeutic modalities in conjunction with electro-sleep therapy., Results and Discussion: The study revealed desynchronization of the endocrine functions in the children with EA that manifests itself as the increased secretion of cortisol and adrenaline, suppressed melatonin and ACTH production, mismatched daytime and nocturnal hormonal levels. The daily bio-rhythmic profile influenced the formation of circadian-type extra systola in the children. The most unfavorable clinical and electrocardiographic patterns were observed in the children with the mixed and night-type arrhythmia. The complex of rehabilitation measures practiced at the Evpatoriya health resort including electro-sleep therapy made it possible to balance the activities of the stress-limiting and stress-implementing systems of the body in the form of normalization of the altered levels of adaptive hormones, ordering of biorhythmical hormonal relationships, and reduction of the number of extrasystoles. The most pronounced effect of the treatment was observed in the group of children with a rare and day-type of arrhythmia to whom electrosleep was prescribed. It is concluded that the significant decrease in the frequency of night-type and mixed-type extrasystoles under effect of electro-sleeptherapy allows to recommend the treatment modality being considered for the correction of this type of heart rhythm disorders.

Objective: To observe the effect of bronchoalveolar lavage on the heart rhythm and conduction of children with severe pneumonia through monitoring the electrocardiogram change of different step of the bronchoalveolar lavage, for proving the safety of the operation of bronchoalveolar lavage from the perspective of cardiac electrophysiology., Method: From July 2011 to March 2012, 30 patients who were hospitalized in pneumology department of Dalian Children's Hospital and met the inclusion criteria and therapeutic indications of bronchoalveolar lavage were chosen. They were 3 to 12 years old, the average age was 5.3 years, including 17 boys and 13 girls, the ratio of boys and girls is 1.3: 1. Continuous sampling the electrocardiogram before and during the process including anesthesia, entering into glottis, lavage, aspiration, and revive, and recording the heart rate, rhythm amplitude and width of P wave, the PR interval, the form and width of QRS complex were also measured. The recorded data were analyzed and statistical analysis to reflect the change of the cardiac electrophysiology., Result: The incidence of heart rate increase was 100.0%, 26 (86.7%) patients began to emerge after anesthesia, the rest of the patients also developed heart rate increase after the start of bronchoscopic operation. All patients had sinus tachycardia, and were most obvious in the progress of lavage and revive. In the process of entering into glottis, lavage, aspiration, 13 (43.3%) patients had arrhythmia episodes. Types of arrhythmia included sinus bradycardia, atrioventricular block and premature beat. Incidences of intraoperative arrhythmia compared with the pre- and post-operation were all statistically significantly different (P = 0.00). The most common arrhythmia were premature beat, in 17 of the 30 cases there were premature beat including 9 cases with atrial premature beats and 8 cases ventricular premature contraction. Two patients had III° atrioventricular block accompanied by serious sinus bradycardia. All kinds of arrhythmias except sinus tachycardia disappeared after the operation was ended. Five patients (16.7%) had PR interval prolongation. Five patients (16.7%) had incomplete right bundle branch block (IRBBB) . Incidences of IRBBB compared with the pre-operation and post-operation were all not significantly different [13.3% (n = 4) vs. 0(n = 0) and 3.3% (n = 1), all P > 0.05]. Different operating progress made no significant difference in the measurement value of electrocardiogram[13.3% (n = 4) vs. 0(n = 0) and 3.3% (n = 1), all P > 0.05], but showed the most notable effect on heart rate., Conclusion: Bronchoalveolar lavage can influence the heart rhythm and conduction, but most of the influence with pathological significance are transient. Cardiac electrophysiological changes were the most obvious in endotracheal operation with the risk of malignant arrhythmia but the risk is low, the bronchoalveolar lavage technique is safe. The contingency plans for dealing with all kinds of adverse reactions must be ready before the operations of bronchoalveolar lavage. During the procedure, the patient's ECG changes should be closely monitored to reduce the incidence of adverse reactions.

A 74-year-old man underwent an electrophysiological study because of Mobitz type II second-degree atrioventricular (AV) block with narrow QRS and frequent junctional extrasystoles. During the study, there were very frequent single His bundle depolarizations with multiple coupling intervals that reproduce the ECG findings. In this case, some His bundle extrasystoles result in retrograde concealed conduction and prolonged local refractoriness in the AV node that manifest as block of the next atrial impulse., (© 2013 Wiley Periodicals, Inc.)

Objective: To evaluate measures of cardiac activity and reactivity as prospective biomarkers of treatment response to an empirically supported behavioral intervention for attention-deficit/hyperactivity disorder (ADHD)., Method: Cardiac preejection period (PEP), an index of sympathetic-linked cardiac activity, and respiratory sinus arrhythmia (RSA), an index of parasympathetic-linked cardiac activity, were assessed among 99 preschool children (ages 4-6 years) with ADHD both at rest and in response to behavioral challenge, before participants and their parents completed 1 of 2 versions of the Incredible Years parent and child interventions., Results: Main effects of PEP activity and reactivity and of RSA activity and reactivity were found. Although samplewide improvements in behavior were observed at posttreatment, those who exhibited lengthened cardiac PEP at rest and reduced PEP reactivity to incentives scored higher on measures of conduct problems and aggression both before and after treatment. In contrast, children who exhibited lower baseline RSA and greater RSA withdrawal scored lower on prosocial behavior before and after treatment. Finally, children who exhibited greater RSA withdrawal scored lower on emotion regulation before and after treatment., Conclusions: We discuss these findings in terms of (a) individual differences in underlying neurobiological systems subserving appetitive (i.e., approach) motivation, emotion regulation, and social affiliation and (b) the need to develop more intensive interventions targeting neurobiologically vulnerable children.

Frequent supraventricular extrasystoles (SVEs) are associated with the subsequent first-time appearance of atrial fibrillation (AF) and ischemic stroke. The aim of this study was to investigate the combined role of SVEs and an AF-related risk score for ischemic stroke, the CHADS2 score, on the occurrence of new AF in patients in sinus rhythm. The Shinken Database 2004-2010 lists 3,263 patients who underwent 24-hour Holter monitoring. A total of 2,589 patients were analyzed, after excluding 674 patients previously diagnosed with AF. Frequent SVEs were defined as ≥102 beats/day (the top quartile) and the presence of a clinical background for a CHADS2 score ≥2 points as a high CHADS2 score. During the mean follow-up period of 571.4 ± 606.4 days, new AF occurred in 38 patients (9.4 per 1,000 patient-years). The incidence of new AF was 2.7 and 37.7 per 1,000 patient-years for patients with nonfrequent SVEs (<102 beats/day) and low CHADS2 scores and those with frequent SVEs and high CHADS2 scores, respectively. Multivariate Cox regression analysis showed that the hazard ratio for frequent SVEs and a high CHADS2 score compared with nonfrequent SVEs and a low CHADS2 score was 9.49 (95% confidence interval 3.20 to 28.15, p <0.001), even after adjustment for gender, age, medications, and echocardiographic parameters. In conclusion, frequent SVEs and a high CHADS2 score independently and synergistically predict the first-time appearance of AF in patients in sinus rhythm, indicating an approximately 10-fold higher risk. Patients meeting these criteria should have more aggressive early intervention for preventing AF., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Preliminary evidence supports an association between OSA and cardiac dysrhythmias. Negative intrathoracic pressure, as occurring during OSA, may provoke cardiac dysrhythmias. Thus, we aimed to study the acute effects of simulated apnea and hypopnea on arrhythmic potential and measures of cardiac repolarization [QT(C) and T (peak) to T (end) intervals [TpTec]) in humans. In 41 healthy volunteers, ECG was continuously recorded prior, during and after simulated obstructive hypopnea (inspiration through a threshold load), simulated apnea (Mueller maneuver), end-expiratory central apnea and normal breathing in randomized order. The number of subjects with premature beats was significantly higher during inspiration through a threshold load (n = 7), and the Mueller maneuver (n = 7) compared to normal breathing (n = 0) (p = 0.008 for all comparisons), but not during end-expiratory central apnea (n = 3, p = 0.125). Inspiration through a threshold load was associated with a non-significant mean (SD) increase of the QT(C) interval [+5.4 (22.4) ms, 95 %CI -1.7 to +12.4 ms, p = 0.168] and a significant increase of the TpTcc interval [+3.7 (8.9) ms, 95 %CI +0.9 to +6.6 ms, p = 0.010]. The Mueller maneuver induced a significant increase of the QT(C) interval [+8.3 (23.4) ms, 95 %CI 0.9 to +15.6 ms, p = 0.035] and the TpTec interval (+4.2 (8.2) ms, 95 %CI +1.6 to +6.8 ms, p = 0.002). There were no significant changes of the QT(C) and TpTec intervals during central end-expiratory apnea. These data indicate that simulated obstructive apnea and hypopnea are associated with an increase of premature beats and prolongation of QT(C) and TpTec intervals. Therefore, negative intrathoracic pressure changes may be a contributory mechanism for the association between OSA and cardiac dysrhythmias.

If a patient has premature beats, it is essential to clarify whether they are associated with a heart disorder or some other disease. The basis for an examination for all patients is the rest-ECG. Ultrasound examination is indicated, if the symptoms are severe or findings indicating a heart disorder are present. The occurrence of severe symptoms, such as episodes of tachycardia and attacks of unconsciousness, is mapped in an interview and they are an indication for further investigations within specialized care. Atrial extrasystoles as such do not require any treatment unless they are accompanied by atrial fibrillation.

Perturbations in the normal heart rate are generally represented by the presence of premature activation (PA) beats in the surface electrocardiogram (ECG). The presence of PA is one of the main reasons of instability in QT dynamics which could initiate arrhythmia. Analyzing Boundary-Input Boundary-Output (BIBO) stability of the short term linear autoregressive QT-RR model is a way of detecting instability in QT dynamics from the ECG. The aim of this paper is to investigate if PA is the only reason for instability in the ventricular repolarisation process, which is denoted by QT interval of surface ECG. Ten healthy subjects with normal sinus rhythm and seven patients with sustained ventricular tachycardia (VT) were analyzed in this study. 10 min long ECG data were collected from each subject of the healthy group and 10 min ECG before the start of VT were taken for each subject of the VT group. Autoregressive QT-RR model was derived for each non-overlapping 1 min long ECG segment of the 10 min long ECG data. Instability in QT dynamics was quantified by measuring the numbers of unstable segments in ECG data for each subject ( ). Results of this study revealed that like the VT group subjects, QT instability detected by QT-RR model is also found in healthy subjects whose ECG segments are mostly free from PA beats. This finding indicates that BIBO unstable QT characteristics might arise from other inherent factors of cardiovascular system in addition to PA.

We present electrocardiograms of a 37 year-old male with frequent extrasystoles and second-degree atrioventricular block. Electrophysiological study confirmed the initial diagnosis of manifest and concealed His bundle ectopy as the cause of his brady- and tachyarrhythmia.

Purpose: Contemporary outcome data of catheter ablation for outflow tract tachycardia (OTT) and ventricular premature beats (VPBs) are rare. The aim of this study was to describe the clinical characteristics, the acute procedure success rate, and the long-term survival of patients who underwent an ablation procedure for OTT or VPBs., Methods: The study was a single-center retrospective cohort study. All 82 consecutive OTT and VPB first ablation procedures between 1999 and 2009 were included. Patients with structural heart disease were excluded., Results: Mean age was 46 ± 13 years. Forty-three percent of the patients were male. All patients were alive after a median follow-up duration of 31 months (interquartile range, 14-65 months). Eighty-nine percent suffered from palpitations and 12 % had a history of syncope. Ventricular tachycardia was documented in 73 % and monomorphic VPBs in 99 %. Seventy-three percent of the patients were ablated in the right ventricular outflow tract, 15 % in the left ventricular outflow tract, and 12 % in the coronary cusps. Radiofrequency energy was used in 95 % of the patients, cryo energy in 9 %. Acute success was achieved in 78 %. Six patients (7 %) experienced a complication (five pericardial effusions, one pseudo-aneurysm of the femoral artery). Three patients needed pericardiocentesis (4 %)., Conclusion: Ablation for OTT and VPB is successful in the vast majority of cases, with a low but still existing complication rate. Long-term survival was excellent, underscoring the benign nature of this arrhythmia.

The presence of recurring arrhythmic events (also known as cardiac dysrhythmia or irregular heartbeats), as well as erroneous beat detection due to low signal quality, significantly affects estimation of both time and frequency domain indices of heart rate variability (HRV). A reliable, real-time classification and correction of ECG-derived heartbeats is a necessary prerequisite for an accurate online monitoring of HRV and cardiovascular control. We have developed a novel point-process-based method for real-time R-R interval error detection and correction. Given an R-wave event, we assume that the length of the next R-R interval follows a physiologically motivated, time-varying inverse Gaussian probability distribution. We then devise an instantaneous automated detection and correction procedure for erroneous and arrhythmic beats by using the information on the probability of occurrence of the observed beat provided by the model. We test our algorithm over two datasets from the PhysioNet archive. The Fantasia normal rhythm database is artificially corrupted with known erroneous beats to test both the detection procedure and correction procedure. The benchmark MIT-BIH Arrhythmia database is further considered to test the detection procedure of real arrhythmic events and compare it with results from previously published algorithms. Our automated algorithm represents an improvement over previous procedures, with best specificity for the detection of correct beats, as well as highest sensitivity to missed and extra beats, artificially misplaced beats, and for real arrhythmic events. A near-optimal heartbeat classification and correction, together with the ability to adapt to time-varying changes of heartbeat dynamics in an online fashion, may provide a solid base for building a more reliable real-time HRV monitoring device.

Introduction: Cardiac arrhythmia findings can be a challenge to interpret and difficult to attribute to background incidence or test article treatment. Thus, there is a growing need to better understand arrhythmia incidence in the experimental animal models used to assess the cardiovascular safety of new drugs. Currently, there is little information on the frequency of spontaneous cardiac arrhythmias in the cynomolgus monkey., Methods: This study evaluated the baseline arrhythmia rate in a group (n=19) of non-naïve (drug-free) male telemetered cynomolgus monkeys at various timepoints over a 6 month period. When sampled, data were collected continuously (24 hour bins over a 6 month period) and the ECG waveforms analyzed for arrhythmia using a semi-automated approach with pattern recognition software. The arrhythmia data were evaluated to detect atrial and ventricular patterns, as well as changes associated with circadian rhythm., Results: Evaluation of this data showed that cynomolgus monkeys can exhibit spontaneous arrhythmias (day cycle; means) of the following types: supraventricular premature contraction (SPC, 10.7%); escape beats (EB, 3.8%); and sinus node pause (SNP, 2.8%), with others below 2%. From the ventricular perspective, ventricular premature beats (VPB, 25.4% (day cycle mean)) were the most prevalent. Circadian analysis indicated that some arrhythmias had higher incidence during the night cycle: SNP (32.6%); EB (18.5%); atrioventricular block (AVB, 2.7%), an indication that the arrhythmia pattern is influenced by the diurnal cycle., Discussion: Overall, the data demonstrated that a variety of spontaneous arrhythmias occur at low frequency in non-treated animals, and the incidence varies between animals, and within the same animal when repeatedly sampled. Given the low incidence in normal animals, continuous ECG sampling over multiple days is needed to establish an accurate arrhythmia "fingerprint" for each animal in dedicated telemetry colonies, which could assist the interpretation of arrhythmia findings that may occur in cardiovascular safety studies., (Copyright © 2012 Elsevier Inc. All rights reserved.)

We describe the case of a 61-year-old woman who underwent successful catheter cryoablation of a symptomatic Hisian ectopy. Diagnosis was based on features of the HV interval assessed from a bipolar recording during mapping. The location of the arrhythmic focus was identified using simultaneous unipolar and bipolar recordings of the His electrogram. This case report highlights the use of 2 new criteria for the diagnosis and mapping of Hisian ectopy, and the successful use of cryothermia for the ablation of extrasystoles arising from the His bundle., (© 2011 Wiley Periodicals, Inc.)

Objective: To investigate the ability of a new stroke volume variation algorithm to predict fluid responsiveness during general anesthesia and mechanical ventilation in animals with multiple extrasystoles., Design: Prospective laboratory animal experiment., Setting: Investigational laboratory., Subjects: Eight instrumented pigs., Interventions: Eight anesthetized and mechanically ventilated pigs were monitored with an arterial line and a pulmonary artery catheter. Multiple extrasystoles were induced by right ventricular pacing (25% of heart beats). Arterial pressure waveforms were recorded and stroke volume variation was computed from the new and from the standard algorithm. The new stroke volume variation algorithm is designed to restore the respiratory component of the arterial pressure waveform despite multiple ectopic heart beats. Cardiac output was measured before and after 56 fluid boluses (7 mL/kg of 6% hydroxy ethyl starch) performed at different volemic states., Measurements and Main Results: A positive response to fluid boluses (>15% increase in cardiac output) was observed in 21 of 56 boluses. The new stroke volume variation was higher in responders than in nonresponders (19% ± 5% vs. 12% ± 3%, p < .05), whereas the standard stroke volume variation was similar in the two groups (29% ± 8% vs. 26% ± 11%, p = .4). Receiver operating characteristic curve analysis showed that the new stroke volume variation was an accurate predictor of fluid responsiveness (sensitivity = 86%, specificity = 85%, best cutoff value = 14%, area under the curve = 0.892 ±, whereas the standard stroke volume variation was not (area under the curve = 0.596 ± 0.077)., Conclusions: In contrast to the standard stroke volume variation, the new stroke volume variation algorithm was able to predict fluid responsiveness in animals with multiple ventricular extrasystoles.

Heart rate variability (HRV) analysis is affected by ectopic beats. An efficient method was proposed to deal with the ectopic beats. The method was based on trend correlation of the heart timing signal. Predictor of R-R interval (RRI) value at ectopic beat time was constructed by the weight calculation and the slope estimation of preceding normal RRI. The type of ectopic beat was detected and replaced by the predictor of RRI. The performance of the simulated signal after ectopic correction was tested by the standard value using power spectrum density (PSD) estimation, whereas the results of clinical data with ectopic beats were compared with the adjacent ectopic-free data. The result showed the frequency indexes after ectopy corrected had less error than other methods with the test of simulated signal and clinical data. It indicated our method could improve the PSD estimation in HRV analysis. The method had advantages of high accuracy and real time properties to recover the sinus node modulation.