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Introduction: Left bundle branch area pacing (LBBAP) is a novel physiological pacing modality. The relationship between the pacing lead tip location and paced electrocardiographic (ECG) characteristics remains unclear. The objectives are to determine the lead tip location within the interventricular septum (IVS) and assess the location-based ECG QRS duration (QRSd) and left ventricular activation time (LVAT)., Methods: This multicenter study enrolled 50 consecutive bradycardia patients who met pacemaker therapy guidelines and received LBBAP implantation via the trans-ventricular septal approach. After at least 3 months postimplant, 12-lead ECGs and pacing parameters were obtained. Cardiac computed tomography (CT) imaging was performed to assess the LBBAP lead tip distance from the LV blood pool., Results: Among the 50 patients, analyzable CT images were obtained in 42. In 23 of the 42 patients, the lead tips were within 2 mm to the LV blood pool (the LV subendocardial (LVSE) group), 13 between 2 and 4 mm (the Near-LVSE group), and the remaining 6 beyond 4 mm (the Mid-LV septal (Mid-LVS) group). No significant differences in paced QRSd were found among the three groups (LVSE, 107 ± 15 ms; Near-LVSE, 106 ± 13 ms; Mid-LVS, 104 ± 15 ms; p = .87). LVAT in the LVSE (64 ± 7 ms) was significantly shorter than in the Mid-LVS (72 ± 8 ms; p < .05), but not significantly different from that in the Near-LVSE (69 ± 8 ms; p > .05)., Conclusion: In routine LBBAP practice, paced narrow QRSd and fast LVAT, indicative of physiological pacing, were consistently achieved for lead tip location in the LV subendocardial or near LV subendocardial region., (© 2022 Wiley Periodicals LLC.)

Purpose: We aimed to evaluate the electrical characteristics and pacing parameters at different locations of His-Purkinje system pacing., Methods: Patients who successfully underwent His-Purkinje system pacing with bradycardia indications from April 2018 to August 2019 were retrospectively analyzed according to the lead location confirmed by visualization of the tricuspid value annulus, postoperative echocardiography, and pacing electrocardiogram. The electrical characteristics and pacing parameters were compared among these patients., Results: A total of 135 patients were retrospectively analyzed. Among them, 30 patients received atrial side HBP (aHBP group), 52 received ventricular side HBP (vHBP group), and 53 received left bundle branch pacing (LBBP group). The proportion of non-selective pacing was significantly lower in aHBP group (30.0%) than in vHBP (75.0%) and LBBP group (90.6%). LBBP had significantly shorter procedural and fluoroscopic duration than aHBP and vHBP. The capture threshold was significantly higher (1.07 ± 0.26 V/1.0 ms vs. 0.89 ± 0.22 V/1.0 ms vs. 0.77 ± 0.18 V/0.4 ms, P < 0.01, respectively), and the R-wave amplitude was significantly lower (3.71 ± 1.72 mV vs. 5.81 ± 2.37 mV vs. 10.27 ± 4.71 mV, P < 0.05 respectively) in aHBP group than those in the other two groups at implantation and during 3-month follow-up. No significant differences were observed in complications among groups during 3-month follow-up., Conclusion: VHBP and LBBP had better pacing performances than aHBP and might be more ideal pacing methods for bradycardia patients., (© 2021. Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Leadless pacemakers are an effective treatment for bradycardia. However, some cases exhibit pericardial effusions, presumably associated with device implantations on the right ventricular free-wall. The present study was carried out to find the ECG features during ventricular pacing with a Micra, which enabled distinguishing free-wall implantations from septal implantations without using imaging modalities., Methods: Thirty-one consecutive patients who received Micra implantations in our facility were enrolled. The location of the device in the right ventricle was evaluated using echocardiography or computed tomography in order to determine whether the device was implanted on the septum (Sep group), apex (Apex group), or free-wall (FW group). The differences in the 12-lead ECG during ventricular pacing by the Micra were analyzed between the Sep and FW groups., Results: The body of the Micra was clearly identifiable in 22 patients. The location of the device was classified into Sep in 12 patients, Apex in 4, and FW in 6. The mean age was highest in the FW and lowest in the Sep group (82.7 ± 6.6 vs. 72.8 ± 8.7 years, p = 0.027). The peak deflection index (PDI) was significantly larger in the FW group than Sep/Apex group in lead V1 (Sep: 0.505 ± 0.010, Apex: 0.402 ± 0.052, FW: 0.617 ± 0.043, p = 0.004) and lead V2 (Sep: 0.450 ± 0.066, Apex: 0.409 ± 0.037, FW: 0.521 ± 0.030, p = 0.011), whereas there was no difference in the QRS duration, transitional zone, and QRS notching., Conclusion: The PDI in V1 could be useful for predicting implantations of Micra devices on the free-wall and may potentially stratify the risk of postprocedural pericardial effusions.

Purpose: Modified Look-Locker inversion recovery (MOLLI) using a 5s(3s)3s scheme is robust to tachycardia, but some errors are occasionally observed in myocardial T 1 mapping. We sought to evaluate the relationship between measurement errors in T 1 mapping and heart rate (HR) using a confidence map., Methods: We enrolled 69 male patients with normal native T 1 values of the septal myocardium measured by a 5s(3s)3s MOLLI. The degree of measurement errors in the septal myocardium was assessed by two independent observers on a confidence map using a 4-point scale: 0, no errors; 1, errors located on the myocardial contour; 2, errors extended into the myocardial contour; and 3, errors extended into the midwall. We compared the scores of measurement errors and the average, maximum, minimum or variability of the HR indicated during the MOLLI scan (iHR), image phases of MOLLI or left ventricular ejection fraction (LVEF)., Results: Patients with score >1 for the septal myocardium had significantly lower minimum iHR than those with a score ≤1 (P < 0.01; 49.8 ± 10.1 vs. 59.6 ± 9.7 beat per min)., Conclusion: The confidence map shows more measurement errors in patients with lower minimum iHR. The myocardial T 1 values should be measured carefully in patients with bradycardia during MOLLI scanning.

Using electrocardiography and echocardiography, we screened elite men and women ballet dancers for abnormal cardiovascular conditions using an observation design with blinded clinical analysis of cardiac function tests. Fifty-eight (females n  = 33) elite professional ballet dancers (age: 26.0 ± 5.7 years, body mass index: 19.9 ± 2.2 kg/m2) with no past or present history of cardiovascular disease volunteered. Participants were assessed via a 12-lead electrocardiography and two-dimensional echocardiography for cardiac function. Electrocardiography revealed that 83% of the dancers demonstrated normal axis, while 31% had incomplete right bundle branch block and 17% had sinus bradycardia; none showed any abnormal findings. Findings from the echocardiography were also normal for all participants and comparable to their counterparts in other sports. Significant differences ( p  < 0.05) were detected in almost all studied echocardiographic parameters between males and females. In conclusion, heart function and structure seem to be normal in elite ballet dancers, placing them at low risk for sudden cardiac death and performance-related cardiovascular complications. Larger samples are required to confirm these findings.

Background: Pregnancy loss prediction based on routinely measured ultrasound characteristics is generally aimed toward distinguishing nonviability. Physicians also use ultrasound indicators for patient counseling, and in some cases to decide upon the frequency of follow-up sonograms. To improve clinical utility, allocation of cut-points should be based on clinical data for multiple sonographic characteristics, be specific to gestational week, and be determined by methods that optimize prediction., Objectives: To identify routinely measured features of the early first trimester ultrasound and the gestational age-specific cut-points that are most predictive of pregnancy loss., Materials and Methods: This was a secondary analysis of 617 pregnant women enrolled in the Effects of Aspirin in Gestation and Reproduction (EAGeR) trial; all women had 1-2 previous pregnancy losses and no documented infertility. Each participant had a single ultrasound with a detectable fetal heartbeat between 6 weeks 0 days and 8 weeks 6 days. Cut-points for low fetal heart rate and small crown-rump length were separately defined for gestational weeks 6, 7, and 8 to optimize prediction. Identity and log-binomial regression models were used to estimate absolute and relative risks, respectively, and 95% confidence intervals between jointly categorized low fetal heart rate, small crown-rump length, and clinical pregnancy loss. Adjusted models accounted for gestational age at ultrasound in weeks. Missing data were addressed using multiple imputation., Results: A total of 64 women experienced a clinical pregnancy loss following the first ultrasound (10.4%), 7 were lost to follow-up (1.1%), and 546 women (88.5%) had a live birth. Low fetal heart rate and small crown-rump length (≤122, 123, and 158 bpm; ≤6.0, 8.5, and 10.9 mm for gestational weeks 6, 7, and 8, respectively) were independent predictors of clinical pregnancy loss, with greatest risks observed for pregnancies having both characteristics (relative risk, 2.08; 95% confidence interval, 1.24-2.91). The combination of low fetal heart rate and small crown-rump length was linked to a 16% (95% confidence interval, 9.1-23%) adjusted absolute increase in risk of subsequent loss, from 5.0% (95% confidence interval, 1.5-8.5%) to 21% (95% confidence interval, 15-27%). Abnormal yolk sac diameter or the presence of a subchorionic hemmhorage did not improve prediction of clinical pregnancy loss., Conclusion: Identified cut-points can be used by physicians for patient counseling, and in some cases to decide upon the frequency of follow-up sonograms. The specified criteria should not be used to diagnose nonviability., (Copyright © 2020. Published by Elsevier Inc.)

A meta-analysis of genome-wide association studies (GWAS) identified eight loci that are associated with heart rate variability (HRV), but candidate genes in these loci remain uncharacterized. We developed an image- and CRISPR/Cas9-based pipeline to systematically characterize candidate genes for HRV in live zebrafish embryos. Nine zebrafish orthologues of six human candidate genes were targeted simultaneously in eggs from fish that transgenically express GFP on smooth muscle cells (Tg[acta2:GFP]), to visualize the beating heart. An automated analysis of repeated 30 s recordings of beating atria in 381 live, intact zebrafish embryos at 2 and 5 days post-fertilization highlighted genes that influence HRV (hcn4 and si:dkey-65j6.2 [KIAA1755]); heart rate (rgs6 and hcn4); and the risk of sinoatrial pauses and arrests (hcn4). Exposure to 10 or 25 µM ivabradine-an open channel blocker of HCNs-for 24 h resulted in a dose-dependent higher HRV and lower heart rate at 5 days post-fertilization. Hence, our screen confirmed the role of established genes for heart rate and rhythm (RGS6 and HCN4); showed that ivabradine reduces heart rate and increases HRV in zebrafish embryos, as it does in humans; and highlighted a novel gene that plays a role in HRV (KIAA1755).

Subarachnoid hemorrhage is a devastating form of stroke with often detrimental outcomes for patients. Here we describe a patient with subarachnoid hemorrhage treated with nimodipine, which resulted in marked bradycardia with junctional atrioventricular heart block. Nimodipine is metabolized predominantly by the cytochrome P450 3A subfamily, and its use is often associated with adverse events, such as hypotension and bradycardia, which can be exacerbated by advanced age. Our patient had the CYP3A5*3/*3 genotype, possibly predisposing her to poor metabolism of this drug. Our case report demonstrates the potential for pharmacogenomics in patients with subarachnoid hemorrhage to help predict their response to nimodipine, minimize adverse drug reactions, and potentially individualize dosing to improve future clinical outcomes.

The need for temporary cardiac pacing may occur in emergency and elective situations and may require transvenous right ventricular lead placement. The treatment of bradyarrhythmias presents the most common perioperative emergency indication. Intraoperatively, temporary rapid right ventricular pacing is accepted as a safe, titratable, and highly reliable method to achieve deliberate hypotension, and it has become a routine practice in the anesthetic management of cardiovascular interventions. The navigation of the lead into the right ventricle often requires fluoroscopy to guide placement and to confirm position. Ultrasound guidance has been accepted widely by perioperative physicians as a safe technique for central venous access. Basic ultrasound and transthoracic echocardiographic skills rapidly are becoming integral to anesthesiologists' practice. When used to guide transvenous pacemaker wire insertion, subcostal echocardiographic imaging offers attractive advantages over blind or fluoroscopic placement, including rapid deployment, avoidance of radiation, real-time visualization of the lead in relation to the cardiac structures, and early detection of potential complications, such as tamponade. Although several articles on echocardiographic guidance for transvenous pacing have been published in other acute care specialty fields in the last decade, this is the first description of the technique and of the recommended echocardiographic views in a perioperative context. In addition, a review of the current literature is presented, and the specific advantages and disadvantages of the approach are discussed in this article., (Copyright © 2019 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Catheter ablation of ganglionated plexus (GP) as cardioneuroablation in the left atrium (LA) has been used to treat vasovagal syncope (VVS)., Objective: The purpose of this study was to assess the effects of ablation of GPs on heart rate and to observe the acute, short-term, and long-term effects after cardioneuroablation., Methods: A total of 115 consecutive patients with VVS who underwent cardioneuroablation were enrolled. GPs of the LA were identified by high-frequency stimulation and/or anatomic landmarks being targeted by radiofrequency catheter ablation., Results: During ablation of right anterior ganglionated plexus (RAGP), heart rate increased from 61.3 ± 12.2 bpm to 82.4 ± 14.7 bpm (P <.001), whereas during ablation of other GPs only vagal responses were observed. During follow-up of 21.4 ± 13.1 months (median 18 months), 106 participants (92.2%) had no recurrence of syncope or presyncope. Holter data showed that minimal heart rate significantly increased at all follow-up time points (all P<.05), and mean heart rate remained higher than baseline 12 months after ablation (P = .001)., Conclusion: Cardioneuroablation via GP ablation in the LA effectively inhibited the recurrence of VVS. Ablation of RAGP could increase heart rate immediately and for the long term. This unique phenomenon may provide a new potential approach for treatment of neural reflex syncope or bradyarrhythmias., (Copyright © 2019. Published by Elsevier Inc.)

Bradycardia is a common complication at the early postoperative period after heart transplantation (HT). The heart rate (HR) usually recovers within a few weeks; however, several patients need a temporary pacemaker or chronotropic agents to stabilize their hemodynamics. Here, we report the first case of transient bradycardia associated with hemodynamic deterioration following HT, which was successfully treated with cilostazol, a phosphodiesterase-3-inhibiting agent. A 59-year-old man received HT for advanced heart failure due to ischemic cardiomyopathy. General fatigue persisted even after the HT. His HR was around 60 beats per minute (bpm) with sinus rhythm. Echocardiography showed no abnormal findings. Right heart catheterization showed that the cardiac index (CI) was 1.9 L/minute/m 2 . Continuous intravenous infusion of isoproterenol (0.003 μg/kg/minute) increased the HR to 80 bpm and CI to 2.7 L/minute/m 2 and improved his symptoms. Isoproterenol was switched to oral administration of cilostazol (100 mg, twice a day), which maintained the HR at around 80 bpm and CI of 2.5 L/minute/m 2 . The patient's HR gradually recovered and cilostazol could be discontinued three months after the HT. Oral administration of cilostazol can be a therapeutic option for patients with sinus bradycardia following HT, who need positive chronotropic support.

Hypothyroidism is rarely included in the differential diagnosis for fetal sinus bradycardia. We report an infant with congenital hypothyroidism caused by ectopic thyroid tissue, who showed antenatal bradycardia. The baseline fetal heart rate was 100-110 bpm at 30 weeks of gestation, and fetal echocardiography revealed sinus bradycardia but no cardiac anomalies. Maternal thyroid function was normal (thyroid-stimulating hormone [TSH] 2.03 μIU/ml, free T3 2.65 pg/ml, and free T4 0.99 ng/dl) when measured at 31 weeks of gestation. Her serum anti SS-A and SS-B antibodies, anti-thyroglobulin, and microsomal antibodies were negative. A male infant without cardiac anomalies was delivered at 35 weeks and 4 days of gestation and admitted for prematurity and respiratory distress syndrome. The infant's heart rate was 70-110 bpm (normal: 120-160 bpm) on admission. On 8 days of age, thyroid function tests revealed that the infant had severe hypothyroidism (TSH 903.3 μIU/ml, free T3 1.05 pg/ml, and free T4 0.26 ng/dl). The prolonged jaundice assumed to be due to hypothyroidism. Oral levothyroxine sodium hydrate (10 μg/kg/day) was immediately started on day 8. After the treatment, the heart rate was gradually increased to 130-140 bpm as the infant's thyroid function was improved (TSH 79.8 μIU/ml, free T3 2.95 pg/dl, and free T4 1.66 ng/dl on day 22). The infant was diagnosed ectopic thyroid tissue because of the high thyroglobulin level (85.9 μg/l). In conclusion, congenital hypothyroidism should be included in the differential diagnosis in cases of fetal bradycardia without cardiac anomalies or maternal autoimmune diseases.

Clinical Features: The patient we present is a 39-year-old woman with a history of hyperthyroidism who developed fast atrial fibrillation secondary to thyrotoxic storm. After the initiation of intravenous diltiazem drip, she developed hypotension, bradycardia, then asystole cardiac arrest., Therapeutic Challenge: It is well known that calcium channel blockers and beta blockers should be used with extreme caution if the patient with thyroid storm has decompensated heart failure with reduced ejection fraction. Despite this, it is recognized that guidelines for the management of thyroid storm do not include an algorithm of action in this situation. Thus, dealing with low-output failure during thyroid storm may pose a critical challenge., Solution: A significant portion of patients with thyrotoxic storm have an underlying low-output cardiac failure. Early identification, proper hemodynamic monitoring, and administration of the agents with appropriate pharmacodynamic profile and therapeutic potentials are essential to avoid treatment-induced cardiogenic shock.

Objective: To date, no systematic work has been intended to describe spatio-temporal patterns of cardiac rhythms using only short series of RR intervals, to facilitate visual or computerized-aided identification of EKG motifs for use in clinical practice. The aim of this study was to detect and classify eye-catching geometric patterns of Poincaré time-delay plots from different types of cardiac rhythms and arrhythmias using short-term EKG signals., Methods: Approximately 150-300 representative, consecutive beats were retrieved from 24-h Holter registers of 100 patients with different heart rhythms. Two-dimensional Poincaré charts were created, and the resulting geometric patterns were transformed into representative familiar eye-catching drawings to interpret different arrhythmias., Results: Poincaré plot representation of RR interval data revealed a wide variety of visual patterns: (i) comet-shaped for sinus rhythm; (ii) torpedo-shaped for sinus bradycardia; (iii) cigarette-shaped for sinus tachycardia; (iv) butterfly-shaped for sinus tachycardia and isolated atrial premature complexes; (v) arrow-shaped for isolated premature complexes and inappropriate sinus tachycardia; (vi) inverted fan-shaped for sinus rhythm with frequent atrial premature complexes; (vii) tornado-shaped for atrial flutter and atrial tachycardia; and (viii) fan-shaped for atrial fibrillation., Conclusions: Modified Poincaré plots with smoothed lines connecting successive points could accurately classify different types of arrhythmias based on short RR interval sequence variability. Characteristic emergent patterns can be visually identified and eventually could be distinguished by an automatic classification system able to discern between arrhythmias. This work provides an alternative method to interpret time-delay plots obtained from short-term EKG signal recordings., (© 2017 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.)

Background and objective : Hypotension and bradycardia are the most common hemodynamic disorders and side effects of spinal anesthesia (SA) on the cardiovascular system. SA-induced sympathetic denervation causes peripheral vasodilatation and redistribution of central blood volume that may lead to decreased venous return to the heart. The aim of the study was to evaluate the changes of inferior vena cava collapsibility index (IVC-CI) during SA in spontaneously breathing patients during elective knee joint replacement surgery to prognose manifestation of intraoperative hypotension and bradycardia. Materials and methods : 60 patients (American Society of Anesthesiologists (ASA) physical status I or II, no clinically significant cardiovascular pathology) of both sexes undergoing elective knee joint replacement surgery under SA were included in the prospective study. Inspiratory and expiratory inferior vena cava (IVCin, IVCex) diameters were measured using an ultrasound device in supine position before and immediately after SA, then 15 min, 30 min, and 45 min after SA was performed. The heart rate, along with systolic, diastolic, and mean arterial blood pressures were collected. The parameters were measured at the baseline and at the next four time points. Results : There were no significant changes in IVCin, IVCex, and IVC-CI compared to baseline and other time point measurements in hypotensive versus nonhypotensive and bradycardic versus nonbradycardic patients ( p > 0.05). Changes in IVC diameter do not prognose hypotension and/or bradycardia during SA: the area under the curve (AUC) of the receiver operating characteristic (ROC) curve for IVC-CI at all measuring points was <0.7, p > 0.05. Conclusions : Reduction in IVC diameters and increase in IVC-CI do not predict hypotension and bradycardia during SA in spontaneously breathing patients undergoing elective knee joint replacement surgery.

We describe the case of a 17-year-old male soccer player with T-wave inversion in precordial leads in resting electrocardiography, which also disclosed sinus bradycardia, early repolarization, and increased QRS voltage. These findings strongly suggested cardiomyopathy. The patient's T-wave inversion disappeared during only 2 weeks of detraining, and it re-appeared 2 weeks after resumption of intensive training. This sudden change in electrocardiographic parameters over a short period helped in identifying the adolescent as having athlete's heart.

This study was to investigate the changes of autonomic nerve function and hemodynamics in patients with vasovagal syncope (VVS) during head-up tilt-table testing (HUT). HUT was performed in 68 patients with unexplained syncope and 18 healthy subjects served as control group. According to whether bradycardia, hypotension or both took place during the onset of syncope, the patients were divided during the test into three subgroups: vasodepressor syncope (VD), cardioinhibitory syncope (CI) and mixed syncope (MX) subgroups. Heart rate, blood pressure, heart rate variability (HRV), and deceleration capacity (DC) were continuously analyzed during HUT. For all the subjects with positive responses, the normalized low frequency (LFn) and the LF/HF ratio markedly decreased whereas normalized high frequency (HFn) increased when syncope occurred. Syncopal period also caused more significant increase in the power of the DC in positive groups. These changes were more exaggerated compared to controls. All the patients were indicative of a sympathetic surge in the presence of withdrawal vagal activity before syncope and a sympathetic inhibition with a vagal predominance at the syncopal stage by the frequency-domain analysis of HRV. With the measurements of DC, a decreased vagal tone before syncope stage and a vagal activation at the syncopal stage were observed. The vagal tone was higher in subjects showing cardioinhibitory responses at the syncopal stage. DC may provide an alternative method to understand the autonomic profile of VVS patients.

Tachyarrhythmias and bradyarrhythmias are often seen in the outpatient setting. Patients can present minimally symptomatic or in extremis. Accurate diagnosis of the rhythm, plus a detailed clinical history, are critical for best management and optimal outcome. A 12-lead electrocardiogram is the cornerstone for diagnosis. Practitioners must identify patients who need immediate transport to an emergency department versus those who can safely wait for an outpatient specialty referral. This article reviews how to accurately diagnose and differentiate the most common tachyarrhythmias and bradyarrhythmias, the associated symptoms, and important concepts for the initial steps in the office management of such arrhythmias., (Copyright © 2017 Elsevier Inc. All rights reserved.)

We describe an interesting case of trigeminocardiac reflex (TCR) caused by selective angiography of the middle meningeal artery (MMA). A 28-year-old woman presented with a symptomatic meningioma. Preoperative tumour embolisation was performed. In the procedure, when selective MMA angiography was done with Omnipaque 300 mg I/mL for 3 mL by manual injection, the patient complained of flashing lights in her eye followed by vomiting and bradycardia down to 40 bpm without increased intracranial pressure signs. On selective MMA angiography, the choroidal crescent and arteries of the periorbital region were opacified by anastomosis from the MMA via the meningo-ophthalmic artery. We diagnosed that her symptoms were caused by selective MMA angiography leading to high pressure stimulation towards the ophthalmic nerve innervation around the orbit as a TCR. We suggest that the operator should be prepared to manage TCR during treatment with expected selective MMA angiography, and gentle low pressure contrast injection should be attempted., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.)

Sphincter of Oddi spasm from opioids has been documented, presenting as severe epigastric pain and potentially overlooked in a differential diagnosis. We present a case of sphincter of Oddi spasm from periarticular morphine in a patient under spinal anesthesia, causing severe distress and treated effectively with glucagon. It is important for anesthesiologists using opioids to consider it as a cause of perioperative pain and be familiar with treatment as it may be refractory by conventional use of opioids for pain relief. It is also important to consider the systemic effects of periarticular absorption, as evident by our case.

Background: Transient bradycardia episodes are common in preterm infants and often secondary to apnea. Decreased ventilation with resultant hypoxemia is believed to be the predominant mechanism. Sudden bradycardias without apnea are also reported, possibly due to vagal stimulation. Point of care ultrasound is used to diagnose and follow cardiovascular complications in preterm infants. Inadvertently, the operator would sometimes capture bradycardia events. This study reports on left ventricular function during such events., Methods: We retrospectively reviewed our cardiac ultrasound database for bradycardia events. Apical four or three chamber images before, during and after a bradycardia event were analysed with speckle tracking software which provides systolic and diastolic parameters of myocardial motion, deformation and volume., Results: Over a 2year period, 15 bradycardia events were noted in 14 patients with a median gestational age of 26weeks (range 23 to 29). Heart rate decreased by an average of 43% (171/min to 98/min). Myocardial velocity and longitudinal strain rate during the atrial component of diastole were reduced during bradycardia. Longitudinal strain during systole was increased and radial deformation was unchanged. Ventricular volumes and ejection fraction did not change. Most parameters returned to baseline values after the event. Longitudinal systolic strain rate remained lower and stroke volume was 12% higher compared to baseline., Conclusion: Parameters of systolic contractility and stroke volume were maintained and parameters of atrial contractility were reduced during mild to moderate bradycardia in preterm infants. Bradycardia reduces total cardiac output with a compensatory increase detected following the event., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

Right ventricular outflow tract (RVOT) septal pacing is commonly performed under the standard fluoroscopic positions during procedure. The aim of the prospective, randomized study was to evaluate the accuracy of the combination of standard fluoroscopic and left lateral (LL) fluoroscopic views for determination of RVOT septal position compared with standard fluoroscopic views alone. We prospectively enrolled patients who had indications for implantation of a permanent pacemaker. Patients were randomly assigned into two groups based on intraoperative fluoroscopic views as follows: LL group (three standard fluoroscopic views + LL fluoroscopic view) or standard group (three standard fluoroscopic views). Transthoracic echocardiography (TTE) determination of pacing sites was applied in all patients 3 days after pacemaker implantation. The implantation success rate of RVOT septal pacing was compared between groups. A total of 143 patients (59 males, mean age 57.6 ± 16.3 years) with symptomatic bradyarrhythmia were studied, of whom, 72 patients were randomized to LL group and 71 to standard group. TTE determination of pacing sites was compared with two groups. In the LL group, 60 patients (83 %) were achieved in RVOT septal position. In the standard group, however, the position of RVOT septum was only observed in 48 patients (68 %). The success rate of RVOT septal position in LL group was significantly higher than standard group (p = 0.029). Comparing to traditional views, combining LL view in the procedure will approve the accuracy of RVOT septal pacing site.

Persistent fetal bradycardia in early pregnancy is a rare finding and indicates towards congenital heart block. This is commonly associated with positive maternal anti-Ro/anti-La antibodies. A case of an asymptomatic primigravida with persistent fetal bradycardia on routine antenatal ultrasound is reported with special emphasis on its management options., (2015 BMJ Publishing Group Ltd.)

Background: Heart failure (HF) can be caused by left ventricular (LV) pump failure as well as by bradyarrhythmias. Hemodynamic differences between HF by LV pump failure and that by bradyarrhythmia have not been fully investigated. We hypothesized that HF by LV pump failure could be associated with both reduced cardiac output (CO) and increased LV filling pressure due to associated LV diastolic dysfunction, whereas HF by bradyarrhythmia could be associated with reduced CO but only modestly increased LV filling pressure due to the absence of LV diastolic dysfunction., Methods: In 39 patients with HF by LV pump failure (LV ejection fraction <35%), 24 with HF by bradyarrhythmia, and 22 normal controls, LV volume, ejection fraction, stroke volume, left atrial volume, and early diastolic mitral valve flow to tissue annular velocity ratio (E/E') were measured by echocardiography., Results: Compared to patients with HF by LV pump failure, those with HF by bradyarrhythmia had significantly lower heart rates, less LV dilatation, preserved LV ejection fraction, preserved stroke volume, similarly reduced cardiac index (1.8 ± 0.4 vs. 1.6 ± 0.4 L/min/m(2), n.s.), preserved LV diastolic function (E') (4.4 ± 2.1 vs. 7.1 ± 2.9 cm/s, p < 0.001), less dilated end-systolic LA volume, and preserved E/E' (24 ± 10 vs. 13 ± 7, p < 0.001)., Conclusions: HF by LV pump failure is characterized by both significantly reduced CO and increased LV filling pressure, whereas HF by bradyarrhythmia is characterized by a similar reduction in CO but only modestly increased LV filling pressure.

In this paper, we propose a new online apnea-bradycardia detection scheme that takes into account not only the instantaneous values of time series, but also their temporal evolution. The detector is based on a set of hidden semi-Markov models, representing the temporal evolution of beat-to-beat interval (RR interval) time series. A preprocessing step, including quantization and delayed version of the observation vector, is also proposed to maximize detection performance. This approach is quantitatively evaluated through simulated and real signals, the latter being acquired in neonatal intensive care units (NICU). Compared to two conventional detectors used in NICU, our best detector shows an improvement on average of around 15 % in sensitivity and 7 % in specificity. Furthermore, a reduced detection delay of approximately 2 s is also observed with respect to conventional detectors.

Objective: To distinguish between blocked atrial bigeminy (BB) and incomplete atrioventricular block with 2:1 conduction (2:1 AVB) can be very difficult, especially in the mid-term fetus. Making a correct diagnosis has important clinical implications, as their prognosis and management differ markedly. Our objective was to investigate whether analysis of isovolumetric time intervals could improve Doppler echocardiography in differentiating these conditions., Methods: Sixteen fetuses with sustained BB or isolated 2:1 AVB, diagnosed at our tertiary center from 2002 to 2012, were reviewed retrospectively. Doppler recordings of left ventricular in- and outflow, including mitral and aortic valve movements, were used to measure isovolumetric contraction (ICT) and relaxation (IRT) time intervals. ICT reference values obtained from 104 normal pregnancies were used for comparison., Results: Ten fetuses had BB and six 2:1 AVB. Five of the AVB cases were anti-Ro antibody positive and one had long QT syndrome (LQTS). ICT was systematically shorter in BB than in antibody-mediated 2:1 AVB. Nine of 10 cases with BB had an ICT below -2 SD and the five with antibody-mediated 2:1 AVB had values at or above +2 SD. All 15 fetuses with either BB or antibody-mediated AVB had an IRT of < 70 ms, as opposed to a markedly prolonged IRT (105 ms) in the LQTS case., Conclusion: Measurement of ICT can improve the differential diagnosis between BB and antibody-mediated 2:1 AVB. Fetuses with BB or antibody-mediated AVB are unlikely to have IRT measurements exceeding 70 ms and, when this is observed, LQTS should be considered a more likely diagnosis., (Copyright © 2014 ISUOG. Published by John Wiley & Sons Ltd.)

The study reported here is a rare case of fetal sinus bradycardia that evolved into symptomatic bradycardia after birth, at which time the implantation of a cardiac pacemaker was indicated. Fetal echocardiography was used to diagnose the type of cardiac rhythm that caused the intra-uterine bradycardia, which enabled the initiation of the appropriate therapy approach and avoided an unnecessary interruption of the pregnancy. However, the details of the sinus bradycardia were impossible to determine in utero in this case due to sinus node dysfunction. After birth, the electrocardiogram results drew attention to a potentially unusual cause of sinus bradycardia, and enabled the diagnosis of this rare disease in this infant.

Study Design: Case report., Objective: to report and discuss the development of sudden symptomatic sinus bradycardia in a 35-year-old woman with acute myelitis., Case Report: A 35-year-old woman presented rapidly progressive weakness and hypoesthesia in the left hemibody. Five days after symptom onset, she developed symptomatic sinus bradycardia up to 30 b.p.m. Bradycardia was completely resolved ∼36 h after its onset., Results: Cervical spine magnetic resonance imaging showed a focal T2-hyperintense intramedullary lesion at C2 level, with moderate cord swelling. The lesion involved bilaterally dorsal funiculi, and left lateral and ventral funiculi. Cardiac I-123 metaiodobenzylguanidine (MIBG) scintigraphy showed a decreased cardiac MIBG uptake suggesting sympathetic denervation., Conclusion: The most likely explanation for bradycardia in our patient is the myelitis-related disruption of descending vasomotor pathways, resulting in sympathetic hypoactivity. Our case extends the spectrum of the clinical presentations of cervical myelitis and emphasizes the importance of careful cardiac monitoring in acute phase of cervical myelitis.

Introduction: Listeriosis is one of the most lethal bacterial diseases for fetuses and infants. However, pregnant women who get infected with Listeria may experience only mild symptoms, making the diagnosis difficult, even when the fetus is fatally infected., Methods: To reveal features of this infection, we conducted a multimodality imaging study of Listeria-induced miscarriage, using a pregnant mouse model. In this model, fetal morbidity and mortality can be observed in utero, noninvasively, and the timing and extent of infection can be carefully controlled. By employing in vivo bioluminescence imaging (BLI), perinatal infections were localized over time such that a correlation of infection to outcome could be determined without the need to kill the animal subject. The morbidity and viability of fetuses were assessed with ultrasound, and fetal morphology was imaged using magnetic resonance imaging (MRI)., Results: The ultrasound revealed sustained fetal bradycardia, the slowing of the fetal heartbeat, in infected fetuses, with an association between slowed fetal heart rate and strong bioluminescent signal., Discussion: Uninfected fetuses showing no bioluminescent signal in the same uterine horn exhibited normal heartbeats. Thus, fetal bradycardia during infection was localized to the infected fetus and was not systemic or disseminated.

Objectives: The purpose of our study was to determine the relationship between the predictive factors and systolic reconstruction (SR) as an optimal reconstruction window in patients with low heart rate (LHR; less than 65 bpm)., Methods: 391 patients (262 male and 129 female, mean age; 67.1±10.1 years of age) underwent coronary CTA without the additional administration of a beta-blocker. Affecting factors for SR were analyzed in age, gender, body weight (BW), diabetes mellitus (DM), coronary arterial disease (CAD), ejection fraction (EF), systolic and diastolic body pressure (BP) and heart rate variability (HRV) during coronary CTA., Results: In 29 (7.4%) of the 391 patients, SR was needed, but there was no apparent characteristic difference between the systolic and diastolic reconstruction groups in terms of gender, age, BW, DM, CAD and EF. In a multivariate analysis, the co-existence of DM [P<0.05; OR, 0.27; 95% CI, 0.092-0.80], diastolic BP [P<0.01; OR, 0.95; 95% CI, 0.92-0.98] and HRV [P<0.01; OR, 0.98; 95% CI, 0.96-0.99] were found to be the factors for SR. In gender-related analysis, HRV was an important factor regardless of sex, but co-existence of DM affected especially for female and BP for male., Conclusion: Especially in the patients with LHR who had a medication of DM, high HRV or high BP, SR, in addition to DR, was needed to obtain high-quality coronary CTA images., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)

A 7.5-year-old male Persian cat with a history of asymptomatic hypertrophic cardiomyopathy was examined for severe lethargy and dyspnoea. Physical examination revealed bradycardia (60 beats/ minute), and ECG investigation revealed persistent atrial standstill that was most likely caused by atrial fibrosis. Persistent atrial standstill is a very rare cardiac condition in cats and is characterized by a complete lack of mechanical, electrical, and possibly endocrine function of the atria. Several pathophysiological mechanisms can cause atrial standstill and include hyperkalaemia, intoxication, and atrialfibrosis. On the basis of the clinical findings, atrial fibrosis was the most likely cause of atrial standstill in this cat. Treatment depends on the underlying cause, but pacemaker implantation can be considered if there are structural abnormalities. The prognosis is guarded in such cases. In this particular case, the cat was euthanized at the owner's request.

Objective: Fetal bradyarrhythmias have various underlying mechanisms. As blocked atrial bigeminy (BB) generally resolves spontaneously, but incomplete atrioventricular block (AVB) might respond to steroid treatment, correct diagnosis is of major importance. Our objectives were to assess the underlying mechanisms in fetal bradyarrhythmia and the accuracy of Doppler techniques in differentiating between them., Methods: Seventy-eight patients referred to our tertiary center between 1990 and 2007 for evaluation of fetal bradycardia were analyzed retrospectively. Besides Doppler recordings from the mitral valve/aorta, superior vena cava/aorta and pulmonary vein/peripheral pulmonary artery, we used recordings from the pulmonary trunk and ductus venosus. We calculated the ratio of the time interval between conducted and consecutive blocked atrial contractions divided by the interval between two conducted atrial beats (a(cb) /a(cc) ), to analyze more meticulously the atrial rhythm in BB and second-degree AVB., Results: Fetal bradycardia ( ≤ 110 bpm) was confirmed in 65 of the 78 referred cases. Twenty-five had AVB (of which 20 were complete AVB), 29 had BB (of which 23 were intermittent) and 11 had sinus bradycardia. The bradyarrhythmic mechanism was identified correctly in all but one fetus with an atrial ectopic rhythm. Heart rates < 65 bpm were not seen in fetuses diagnosed with BB and rates < 60 bpm were seen only in cases with complete AVB, but heart rate did not distinguish between BB and AVB in the 60-75 bpm range. The a(cb) /a(cc) ratio clearly differentiated between fetsues with BB and those with second-degree AVB, including during midgestation, when it was difficult to distinguish these fetuses., Conclusions: Using Doppler flow recordings, the mechanism causing fetal bradycardia can be clarified. In most cases this can be accomplished by visual validation only, and meticulous measurements are needed mainly to distinguish midterm fetuses with BB from those with second-degree AVB., (Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.)

Objective: To evaluate image quality (IQ) and radiation exposure of coronary computed tomographic angiography (CTA) with prospectively electrocardiographic (ECG) triggered high-pitch spiral acquisition using dual source CT., Methods: Totally 75 consecutive patients with a stable heart rate (HR) ≤65 bpm underwent coronary CTA. patients were divided into two groups according to their HR (group A HR≤60 bpm, group B HR >60 bpm to≤65 bpm) . A dual-source CT scanner was used (0.6mm collimation, 0.28s rotation time, 80~100 kV, 370 mAs/rot) . Data acquisition was prospectively ECG-triggered at 60% of the R-R interval with a pitch of 3.4. Images were reconstructed with 75ms temporal resolution, 0.75mm slice thickness and 0.5mm increment. IQ was evaluated using a four-point scale (1=excellent, 4=unevaluable) ., Results: The mean HR and scan time of all patients was (57.2 ± 4.8) bpm and (0.42 ± 0.02) s. Of 1103 coronary artery segments, 934 (84.7%) had an IQ score of 1, 135 (12.2%) score of 2, 18 (1.6%) score of 3,and 16 (1.5%) were rated as unevaluable. There was no significant difference between the two groups in IQ [mean score (1.19 ± 0.52 vs. 1.22 ± 0.55;Z=-1.107,P=0.268) . The rate of evaluable segments showed no significant difference between the two groups (98.5% vs. 98.6%;X2=0.000,P=1.000) . Mean dose-length product of all patients was (67.2 ± 30.4) mGy × cm, mean effective dose was (0.94 ± 0.43) mSv., Conclusion: In patients with a stable HR of 65 bpm or less, prospectively ECG-triggered high-pitch spiral CT acquisition provides high IQ at low radiation dose.

An 18-year-old male patient presented with a 3-year history of exertional dyspnea, dizziness, and angina. Echocardiography showed advanced hypertrophy of the left ventricle (LV), right ventricle (RV) free wall, and interventricular septum. There were apparent muscular bundles especially at the level of the right ventricular outflow tract (RVOT). Maximal pressure gradients across the RVOT and left ventricular outflow tract (LVOT) were 141 mmHg and 66 mmHg, respectively. There was also grade 2 aortic regurgitation. Transesophageal echocardiography and cardiac magnetic resonance imaging confirmed these findings. Despite treatment with propranolol and cibenzoline, the patient remained symptomatic with unchanged pressure gradients. Corrective surgery including an extensive muscular resection of the RVOT, minimal resection of the LVOT, and interposition of a graft patch in the RVOT resulted in complete disappearance of the RVOT gradient and a significant decrease to 28 mmHg in the LVOT gradient. During a year follow-up, aortic valvular insufficiency remained clinically stable and the patient was asymptomatic. This is the first case of hypertrophic obstructive cardiomyopathy with predominant RVOT obstruction treated by myectomy and patch graft interpositioning.

Objective: The study objective was to compare the left ventricular (LV) dyssynchrony and torsional behavior between right ventricular apical (RVA) and right ventricular septal (RVS) pacing., Methods: Forty-six patients with symptomatic sick sinus syndrome and preserved LV function were assigned to 2 groups: RVA (n = 23) and RVS (n = 23). Echocardiographic study including two-dimensional speckle tracking imaging was performed in the AAI and DDD modes., Results: Mean QRS width during DDD mode was significantly longer with RVA pacing than with RVS pacing. Dyssynchrony, torsion, and untwisting rate during DDD mode were significantly worse with RVA than with RVS pacing. In patients with RVA pacing, there was an increase in longitudinal dyssynchrony from AAI to DDD mode that significantly correlated with the deterioration of untwisting rate., Conclusion: In bradyarrhythmic patients with preserved LV function, RVS pacing resulted in a reduced LV dyssynchrony and better torsional behavior than RVA pacing., (Copyright 2010 American Society of Echocardiography. Published by Mosby, Inc. All rights reserved.)

Background: Multisite atrial pacing (MAP) was introduced to improve atrial electrical synchrony and prevent recurrence of atrial fibrillation (AF)., Methods and Results: In the present study there were 57 patients with sinus node disease, AF recurrence and prolonged P-wave on ECG with 2 MAP modalities. In all patients 1 lead was implanted in the coronary sinus (CS) ostium area. In the right atrial appendage (RAA)+CS group (28 patients) the other atrial lead was in the RAA, and in the BB+CS group (29 patients) in the Bachmann's bundle (BB) region. Tissue Doppler was used to register the electromechanical delay (EMD) in the atrial walls and estimate the atrial contraction synchrony. Cardiac output and myocardial performance index did not differ during the 2 MAP modalities. During BB+CS, in comparison with RAA+CS pacing, the peak of the mitral atrial wave occurred earlier (P<0.01), the usual right-left atrial contraction sequence was reversed more frequently (P<0.004), all atrial EMDs except for the lateral left atrium (LA) were shorter (P<0.05), and LA synchrony was greater (P<0.001)., Conclusions: In patients treated with MAP, implanting 1 of the atrial leads in the BB area instead of the RAA has no influence on global cardiac hemodynamics, but does result in earlier LA contraction, and reversal of the typical right-left atrial contraction sequence, as well as providing greater LA contraction synchrony.