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Background Electrocardiogram (ECG) is a widely accessible diagnostic tool that can easily be obtained on admission and can reduce excessive contact with coronavirus disease 2019 (COVID‐19) patients. A systematic review and meta‐analysis were performed to evaluate the latest evidence on the association of ECG on admission and the poor outcomes in COVID‐19. Methods A literature search was conducted on online databases for observational studies evaluating ECG parameters and composite poor outcomes comprising ICU admission, severe illness, and mortality in COVID‐19 patients. Results A total of 2,539 patients from seven studies were included in this analysis. Pooled analysis showed that a longer corrected QT (QTc) interval and more frequent prolonged QTc interval were associated with composite poor outcome ([WMD 6.04 [2.62‐9.45], P = .001; I 2:0%] and [RR 1.89 [1.52‐2.36], P, Electrocardiography abnormalities on admission, including longer QTc interval and prolonged QTc interval, longer QRS duration, a faster heart rate, the presence of LBBB, PAC, PVC, T‐wave inversion, and ST‐depression are significantly associated with an increased composite poor outcome in patients with COVID‐19.

Background The role of nonpulmonary vein (PV) triggers ablation in persistent atrial fibrillation (PEAF) was suggested but it is still under debate. Objectives We aimed to assess the effectiveness of non-PV trigger-targeted ablation for patients with PEAF. Methods Consecutive patients with PEAF undergoing catheter ablation (CA) between January 2015 and April 2017 were enrolled. Isoproterenol plus adenosine challenge was performed to provoke non-PV triggers. Non-PV triggers were defined as the trigger beats inducing AF (non-PV AF triggers) and/or frequent premature contractions (non-PV PACs) from other than PVs. Three groups were defined: Group 1 (n = 186) without non-PV triggers; Group 2 (n = 65) with non-PV triggers that could be completely eliminated with CA; Group 3 (n = 49) with non-PV triggers still inducible after CA. The primary endpoint was freedom from any atrial tachyarrhythmia (ATa) recurrence. Results A total of 300 patients (230 males, age 64 ± 10) were enrolled. The mean follow-up period was 27 ± 10 months. Freedom from ATa recurrence at 1 and 2 years were significantly lower in Group 3 compared to the other two groups (Group 1; 74.7%, 67.2% vs. Group 2; 75.8%, 68.3% vs. Group 3: 52.1%, 38.6%, p = .0005), irrespective of the type of non-PV triggers (non-PV AF triggers vs. non-PV PACs). On multivariate analysis, unsuccessful elimination of non-PV triggers was an independent predictor for ATa recurrence (hazard ratio = 1.80, 95% confidence interval = 1.07-2.95, p = .026). Conclusion Successful non-PV triggers elimination can improve the ATa recurrence rate in PEAF ablation. ATa recurrence rate is higher, if non-PV AF triggers or even non-PV PACs remain in patients with PEAF.

Aim The purpose of this study was to establish a simple method to distinguish premature ventricular contractions (PVC) from premature atrial contractions (PAC) using a fetal Doppler ultrasound arterial pulse waveform to measure time intervals between sinus node restarting. Methods We retrospectively identified 14 fetuses with premature contraction (8 with PAC, 6 with PVC). We measured two distinct parts of time intervals using an arterial pulsed‐wave Doppler: the two consecutive waveforms just before the premature contraction (2‐V interval) and two consecutive waveforms including the premature contraction (XV interval) to measure time intervals between sinus node restarting. We then evaluated the time difference between the 2‐V and XV intervals in PVC compared to PAC. Results For PVC, the difference between the 2‐V interval and the XV interval was significantly shorter than that for PAC. A cut‐off point of 33 ms, where a difference ≤33 ms was clearly shown to be associated with a PVC and a difference more than 33 ms signified a PAC was demonstrated. Conclusion The 2‐V and XV interval measurements, used to measure time intervals between sinus node restarting, could easily distinguish PVC from PAC in utero. Therefore, this study could potentially be a feasible and effective method for obstetricians or sonographers to employ usefully.

This is a case of a 63‐year‐old female presenting with diabetes mellitus, hypertension, hypothyroidism, and postmenopausal osteoporosis with findings showing abnormal AFT with reduced heart rate variability (HRV) and multiple lobed Poincaré plot, pointing to premature atrial contractions.

INTRODUCTION Frequent premature ventricular contractions (PVCs) can cause cardiomyopathy (CM). Postextrasystolic potentiation (PESP) and irregularity have been in implicated as triggers of PVC-CM. Because both phenomena can also be found in premature atrial contractions (PACs), it is speculated that frequent PACs have similar consequences. METHODS AND RESULTS A single-center, retrospective study included all consecutive patients undergoing a 14-day Holter monitors (November 2014 to October 2016). Patients were divided into four groups by ectopy burden group 1 (

The presence of bradycardic arrhythmias during volitional apnea at altitude may be caused by chemoreflex activation/sensitization. We investigated whether bradyarrhythmic episodes became prevalent in apnea following short‐term hypoxia exposure. Electrocardiograms (ECG; lead II) were collected from 22 low‐altitude residents (F = 12; age=25 ± 5 years) at 671 m. Participants were exposed to normobaric hypoxia (Spo 2 ~79 ± 3%) over a 5‐h period. ECG rhythms were assessed during both free‐breathing and maximal volitional end‐expiratory and end‐inspiratory apnea at baseline during normoxia and hypoxia exposure (20 min [AHX]; 5 h [HX5]). Free‐breathing HR became elevated at AHX (78 ± 10 bpm; p, In this study, voluntary apnea was used to determine whether significant chemoreceptor sensitivity develops following 5 h of normobaric hypoxia, as evident through significant bradycardia and arrhythmogenesis. The results showed that bradycardia and the incidence of arrhythmogenesis was similar between initial hypoxia exposures, as well as after 5 h of exposure. These findings demonstrate previously documented bradyarrhythmogenesis is a unique phenomenon to chronic hypoxia exposure (i.e., several days residency at altitude).

OBJECTIVES This study assessed if frequent premature atrial contractions (PACs) were associated with decreased left atrial (LA) strain and adverse remodeling. BACKGROUND Left atrial dysfunction and enlargement increases risk of stroke. If frequent PACs cause LA dysfunction and remodeling, PAC suppressive therapy may be beneficial. METHODS Inclusion criteria were age ≥18 years and sinus rhythm. Exclusion criteria were atrial fibrillation or any etiology for LA enlargement. Hundred and thirty-two patients with frequent PACs (≥100/24 hours) by Holter were matched to controls. Speckle tracking strain of the left atrium was performed from the 4-chamber view. Strain measurements were LA peak contractile, reservoir and conduit strain and strain rates. RESULTS In the frequent PAC vs control group, PACs were more frequent (1959 ± 3796 vs 28 ± 25/24 hours, P

BACKGROUND: Atrial remodeling, vagal tone, and atrial ectopic triggers are suggested to contribute to increased incidence of atrial fibrillation (AF) in endurance athletes. How these parameters change with increased lifetime training hours is debated. HYPOTHESIS: Atrial remodeling occurs in proportion to total training history, thus contributing to elevated risk of AF. METHODS: We recruited 99 recreational endurance athletes, subsequently grouped according to lifetime training hours, to undergo evaluation of atrial size, autonomic modulation, and atrial ectopy. Athletes were grouped by self‐reported lifetime training hours: low (6000 h). Left atrial (LA) volume, left ventricular (LV) dimensions, and LV systolic and diastolic function were assessed by echocardiography. We used 48‐hour ambulatory electrocardiographic monitoring to determine heart rate, heart rate variability, premature atrial contractions, and premature ventricular contractions. RESULTS: LA volume was significantly greater in the high (+5.1 mL/m(2), 95% CI: 1.3–8.9) and medium (+4.2 mL/m(2), 95% CI: 0.2–8.1) groups, compared with the low group. LA dilation was observed in 19.4%, 12.9%, and 0% of the high, medium, and low groups, respectively (P = 0.05). No differences were observed between groups for measures of LV dimensions or function. Minimum heart rate, parasympathetic tone expressed using heart rate variability indices, and premature atrial contraction and premature ventricular contraction frequencies did not differ between groups. CONCLUSIONS: In recreational endurance athletes, increased lifetime training is associated with LA dilation in the absence of increased vagal parameters or atrial ectopy, which may promote incidence of AF in this cohort.

BACKGROUND: We aimed to explore electrophysiological characteristics of premature atrial contractions (PACs) originating from pulmonary veins (PVs) and non‐PVs and to evaluate the effectiveness and safety of catheter ablation for PACs. HYPOTHESIS: Symptomatic PACs originated from different positions and whether could be ablated. METHODS: Symptomatic, frequent, and drug‐refractory PAC patients were enrolled in this study. All patients underwent electrophysiological study and catheter ablation. RESULTS: A total of 81 patients were enrolled: 45 patients with PACs originating from PVs (group A), 24 patients with PACs originating from non‐PVs (group B), and 12 patients with PACs arising from both PVs and non‐PVs (group C). Twenty (44.4%) patients in group A, 6 (50.0%) patients in group C, and 3 (12.5%) patients in group B presented paroxysmal atrial fibrillation (P

Introduction The significance of premature atrial contraction (PAC) count and supraventricular runs (SVR) for the risk of development of new-onset atrial fibrillation (AF) in patients with coronary artery disease (CAD) is not well established. Methods The Innovation to Reduce Cardiovascular Complications of Diabetes at the Intersection (ARTEMIS) study cohort consisted of 1946 patients with CAD who underwent clinical and echocardiographic examinations, 24-hour ambulatory ECG monitoring and laboratory tests. After excluding patients who were not in sinus rhythm at baseline or were lost from the follow-up, the present study included 1710 patients. SVR was defined as at least 4 PACs in a row with a duration

Background Our aim is to present average values and prevalence of electrocardiographic (ECG) abnormalities among the general Dutch population in the LifeLines Cohort. Hypothesis The ECG values previously studied in the Caucasian population of smaller cohorts will be confirmed with ECG data from LifeLines. Methods ECG data of 152 180 individuals age 18 to 93 years were available. Individuals with cardiovascular risk factors were excluded to analyze the healthy population. Average values of the ECG for the healthy population were presented as means with 95% and 99% confidence intervals and as medians with first and 99th percentiles. Results Median heart rate was highest in the youngest and oldest individuals of the healthy population. Median duration of P wave, PQ interval, and QRS duration were longer in males compared with females. In contrast, median QT interval corrected for heart rate was higher in females. In general, the above-mentioned parameters increased with age. The prevalences of ECG abnormalities adjusted for the Dutch population were 0.9% for atrial fibrillation or flutter, 1.4% for premature atrial complexes, 0.5% for myocardial infarction, 2.1% for ventricular premature complexes, 1.0% for left ventricular hypertrophy, 8.1% for P-R interval >200 ms, and 0.8% for bundle branch block. Conclusions Our study provides an overview of average values and ECG abnormalities and confirms data of previous smaller studies. In addition, we evaluate the age- and sex-dependent normal limits of the P wave and QRS duration and confirm in detail the frontal plane QRS-T angle on the ECG.

Background: although previous studies reported frequent premature atrial contractions(fPACs) increased the risk of adverse cardiovascular outcomes, especially atrial fibrillation(AF), there is a substantial inconsistency between reports concerning the definition of fPAC. In this study, we aimed to investigate the relationship between fPAC and cardiovascular outcomes, especially AF. We further searched for a cutoff value of fPAC for prediction of AF. Methods: we retrospectively analyzed the ambulatory 24-hr Holter monitoring records and 392 patients included. Frequent PAC was defined as more than 720 PAC/24 hr as used for frequent ventricular premature beats. Patients’ baseline characteristics, echocardiographic variables and medical history were recorded. Results: there were 189 patients with fPAC and 203 patients without fPAC. Patients with fPAC had more comorbidities in terms of hypertension, diabetes mellitus, coronary artery disease and congestive heart failure. CHA2DS2-VaSc was higher in patients with fPAC. Mean follow-up duration was 31 months, and the number of patients with new-onset AF during follow-up was significantly higher in fPAC group (22% vs. 5%, p, NA

Automated Arrhythmia Discrimination Using a SmartphoneBackground Atrial fibrillation (AF) is a common and dangerous rhythm abnormality. Smartphones are increasingly used for mobile health applications by older patients at risk for AF and may be useful for AF screening. Objectives To test whether an enhanced smartphone app for AF detection can discriminate between sinus rhythm (SR), AF, premature atrial contractions (PACs), and premature ventricular contractions (PVCs). Methods We analyzed two hundred and nineteen 2-minute pulse recordings from 121 participants with AF (n = 98), PACs (n = 15), or PVCs (n = 15) using an iPhone 4S. We obtained pulsatile time series recordings in 91 participants after successful cardioversion to sinus rhythm from preexisting AF. The PULSE-SMART app conducted pulse analysis using 3 methods (Root Mean Square of Successive RR Differences; Shannon Entropy; Poincare plot). We examined the sensitivity, specificity, and predictive accuracy of the app for AF, PAC, and PVC discrimination from sinus rhythm using the 12-lead EKG or 3-lead telemetry as the gold standard. We also administered a brief usability questionnaire to a subgroup (n = 65) of app users. Results The smartphone-based app demonstrated excellent sensitivity (0.970), specificity (0.935), and accuracy (0.951) for real-time identification of an irregular pulse during AF. The app also showed good accuracy for PAC (0.955) and PVC discrimination (0.960). The vast majority of surveyed app users (83%) reported that it was “useful” and “not complex” to use. Conclusion A smartphone app can accurately discriminate pulse recordings during AF from sinus rhythm, PACs, and PVCs.

Fibrosis Architecture and Conduction in Chronic AF Introduction Patients with paroxysmal atrial fibrillation (AF) often transition between sinus rhythm and AF. For AF to initiate there must be both a trigger and a substrate that facilitates reentrant activity. This trigger is often caused by a premature atrial contraction or focal activations within the atrium. We hypothesize that specific architectures of fibrosis alter local conduction to enable AF. Methods and Results Control goats (n = 13) and goats in chronic AF (for an average of 6 months, n = 6) had a high-density electrode plaque placed on the LA appendage. Conduction patterns following a premature atrial contraction, caused by an electrical stimulation, were quantified to determine regions of conduction slowing. These regions were compared to architecture, either diffuse fibrosis or regions of obstructive fibrosis, and overall fibrosis levels as determined by histology from the mapped region. The chronic AF goats had more obstructive fibrosis than the controls (17.5 ± 8.0 fibers/mm2 vs. 8.6 ± 3.0 fibers/mm2). Conduction velocity of the AF goats was significantly slowed compared to the control goats in the transverse direction (0.40 ± 0.04 m/s vs. 0.53 ± 0.15 m/s) but not in the longitudinal direction (0.70 ± 0.27 m/s vs. 0.76 ± 0.18 m/s). Conclusions AF-induced atrial remodeling leads to increased obstructive fibrosis and conduction velocity slowing transverse to fiber orientation following premature stimuli. The decrease in conduction velocity causes a decrease in the cardiac wavelength, and increases the likelihood of reentry and AF onset.

BACKGROUND Echocardiography screening in anti-SSA antibody exposed fetuses is controversial. OBJECTIVE The aim of this study is to evaluate utility of fetal echocardiography in anti-SSA exposure. METHODS Echocardiograms performed over 9 years for maternal anti-SSA exposure were reviewed for atrioventricular (AV) block, cardiomyopathy, arrhythmias, effusion, valve abnormalities, or other abnormalities identified by the echocardiographer. Fetuses with AV block referred to our institution and subsequently found to be anti-SSA exposed were also identified. RESULTS Six hundred thirty six echocardiograms were performed on 140 fetuses (Cohort 1) of 134 women screened for maternal anti-SSA +/− anti-SSB antibodies. No fetuses developed second or third-degree AV block or cardiomyopathy (odds ratio 0.1, CI 0.0051 to 1.9410, p = 0.13). Dexamethasone was administered to three fetuses for sinus bradycardia, echogenicity near AV node, and ventricular systolic dysfunction with valve regurgitation; all normalized. Screening echocardiograms identified: sinus bradycardia (n = 1), PR prolongation (n = 5), premature atrial contractions (n = 3), valve regurgitation (n = 24), echogenic myocardium (n = 4), and pericardial effusion (n = 1). Isolated tricuspid regurgitation and first-degree AV block did not progress. Nine cases of SSA-mediated AV block (Cohort 2) were referred after heart block developed. CONCLUSIONS Serial fetal echocardiography in anti-SSA exposed fetuses did not detect AV block. In rare cases, dexamethasone treatment may have affected disease course. © 2014 John Wiley & Sons, Ltd.

Background: The aim of this study was to determine the frequency and nature of errors made by computer electrocardiogram (ECG) analysis of atrial fibrillation (AF), and the clinical consequences. Hypothesis: Computer software for interpreting ECGs has advanced. Methods: A total of 10279 ECGs were collected, automatically interpreted by the built-in ECG software, and then reread by 2 cardiologists. AF-related ECGs were classified into 3 groups: overinterpreted AF (rhythms other than AF interpreted as AF), misinterpreted AF (AF interpreted as rhythms other than AF), and true AF (AF interpreted as AF by both computer ECG interpretation and cardiologists). Results: There were 1057 AF-related ECGs from 409 patients. Among these, 840 ECGs (79.5%) were true AF. Overinterpretation occurred in 98 (9.3%) cases. Sinus rhythm and sinus tachycardia with premature atrial contraction and/or baseline artifact and sinus arrhythmia were commonly overinterpreted as AF. Heart rate ≤60 bpm and baseline artifact significantly increased the likelihood of overinterpreted AF. Misdiagnosis occurred in 119 (11.3%) cases, in which AF was usually misdiagnosed as sinus or supraventricular tachycardia. The presence of tachycardia and low-amplitude atrial activity significantly increased the likelihood of misdiagnosis of AF. Among the erroneous computer ECG interpretations, 17 cases (7.8%) were not corrected by the ordering physicians and/or repeat computer-ECG interpretation; inappropriate follow-up studies or treatments of the patients were undertaken with no serious sequelae. Conclusions: Erroneous computer ECG interpretation of AF was not rare. Attention should be concentrated on educating physicians about ECG appearance and confounding factors of AF, along with ongoing quality control of built-in software for automatic ECG interpretation. Clin. Cardiol. 2012 DOI: 10.1002/clc.22000 The authors have no funding, financial relationships, or conflicts of interest to disclose.

Here, we present a rare case of fetal bradyarrhythmia following magnesium sulfate therapy for preterm labor. After we switched treatment from ritodrine hydrochloride to magnesium sulfate at 25 weeks' gestation, the fetal heart rate dropped from 150 bpm to 80–100 bpm. Fetal echocardiography and magnetocardiography indicated bigeminy and trigeminy of blocked premature atrial contractions. It is well known that magnesium sulfate decreases the baseline and variability of fetal heart rate. Studies have reported a substantial decrease of 2–15 bpm in the baseline fetal heart rate, and magnesium has various effects on fetal heart rate patterns with a lower baseline fetal heart rate within the normal range of 110–160 bpm. This is the first report of magnesium sulfate-induced fetal bradyarrhythmia by prolongation of the refractory period of the atrioventricular node in the case of blocked premature atrial contractions. Clinicians should consider fetal bradyarrhythmia when the baseline fetal heart rate drops to

Objective Delineate prenatal features of Costello syndrome (caused by HRAS mutations), which consists of mental retardation, facial, cardiovascular, skin, and musculoskeletal anomalies, and tumor predisposition. Methods Literature and new cases classified as Group I (pre-HRAS), Group II (HRAS confirmed), and Group III (HRAS confirmed in natural history study, plus three contributed cases). Results Polyhydramnios occurred in most (mean 79%) pregnancies of cases in Groups I (98), II (107), and III (17); advanced paternal age and prematurity were noted in approximately half. Less frequent were nuchal thickening, ascites, shortened long bones, abnormal hand posture, ventriculomegaly, macrosomia, and macrocephaly. Fetal arrhythmia occurred in nine cases (six supraventricular or unspecified tachycardia, one unspecified arrhythmia, and two premature atrial contractions, PACs); excluding three new cases and two with PACs, the estimated prenatal frequency is 4/222 (2%). Conclusion Costello syndrome can be suspected prenatally when polyhydramnios is accompanied by nuchal thickening, hydrops, shortened long bones, abnormal hand posture, ventriculomegaly, large size, and macrocephaly, and especially fetal atrial tachycardia. Consideration should be given for timely prenatal diagnostic studies for confirmative HRAS gene mutations and for maternal treatment of serious fetal arrhythmia. Copyright © 2009 John Wiley & Sons, Ltd.

Background The heart is susceptible to recurrence of atrial fibrillation (AF) during the period immediately following conversion to sinus rhythm (SR). It is less clear whether various onset or trigger mechanisms can predict AF recurrence after direct current (DC) cardioversion of persistent AF. Methods In this study, 172 patients (117 men), mean age 69 ± 11 y, and with persistent AF underwent elective electrical cardioversion. A detailed analysis was made of the heart rhythm and potential AF trigger mechanisms based on 5 min electrocardiogram (ECG) recordings after conversion. Results Of 151 patients discharged in SR, 45 (30%) had a recurrence of AF within 1 wk. Premature atrial contractions (PACs) were the most common potential trigger, occurring on an average of 3/min. They were equally frequent in patients with and without immediate and early reinitiation of AF, and in patients with and without AF recurrence at the 1-wk follow-up visit. Other trigger mechanisms were too infrequent to allow conclusions. Conclusion Premature atrial contractions were the most common potential trigger mechanism occurring immediately after cardioversion in patients with persistent AF. However, they neither predicted immediate and/or early reinitiations, nor recurrences during the first wk after cardioversion. Copyright © 2008 Wiley Periodicals, Inc.

Background:Detailed information on swallowing-induced tachyarrhythmias has been lacking. Methods:The prevalence, characteristics, and results of the radiofrequency catheter ablation (RFCA) of swallowing-induced tachyarrhythmias were examined in 544 patients with symptomatic premature atrial contractions (PACs), paroxysmal atrial tachycardia (AT), and/or paroxysmal atrial fibrillation (AF). We also conducted a search of the medical literature on swallowing-induced tachyarrhythmias. Further, we presented an in-depth review of the literature and investigated the published data on swallowing-induced tachyarrhythmias. Results:The prevalence of swallowing-induced tachyarrhythmias was 0.6% (three patients). An analysis of the published literature and our three cases demonstrated that (1) males predominated 9:1 over females, (2) most cases occurred over 35 years of age, (3) tachyarrhythmias occurred consistently and reproducibly shortly after each swallow, (4) 90% of the patients had PACs and/or AT as the manifesting arrhythmia, (5) the PACs provoked by swallowing usually had the same P-wave morphology as the first beat of the AT and AF, and (6) RFCA procedures performed in five cases resulted in success with no recurrence or complications. Conclusions:Swallowing-induced tachyarrhythmias are rare, but have several distinct characteristics. RFCA should be considered in appropriately selected patients with reliable inducibility because such an ablation may offer a permanent cure.

Objectives: The VIP registry investigated the efficacy of preventive pacing algorithm selection in reducing atrial fibrillation (AF) burden. Background: There are few data identifying which patients might benefit most from which preventive pacing algorithms. Methods: Patients, with at least one documented AF episode and a conventional antibradycardia indication for pacemaker therapy, were enrolled. They received pacemakers with AF diagnostics and four preventive algorithms (Selection and PreventAF series, Vitatron). A 3-month Diagnostic Phase with conventional pacing identified a Substrate Group (>70% of AF episodes with

UNLABELLED: Dissociated pulmonary vein rhythm. INTRODUCTION: Characterization of the electrophysiologic behavior of the pulmonary vein (PV) triggers initiating atrial fibrillation (AF) is still lacking. We conducted the current study to evaluate the behavior of the dissociated PV rhythm (PVD) observed after electrical disconnection from the left atrium of the PV responsible for initiation of AF. METHODS AND RESULTS: Four hundred and seven consecutive patients (102 women; mean age 55+/-11 years) presented for ablation of symptomatic AF to our laboratory. After isolation, sustained dissociated rhythm (>10 minutes) was documented in 2.1% (34 of 1,568 PVs) of the PVs (initiating AF prior to isolation). Adenosine (18 mg IV bolus), verapamil (10 mg IV bolus), phenylephrine (200 mcg bolus followed by infusion at 100 mcg/hour), and isoproterenol (infusion rate of 15 mcg/hour) were administered in these patients. The cycle length of the PV rhythm before and after the administration of drugs was measured. Adenosine prolonged the sinus node (SN) cycle length (from 750+/-105 to 1,900+/-200 ms; P

Objectives To test the usefulness and reliability of fetal magnetocardiography as a diagnostic or screening tool, both for fetuses with arrhythmias as well as for fetuses with a congenital heart defect. Methods We describe 21 women with either a fetal arrhythmia or a congenital heart defect discovered during prenatal evaluation by sonography. Four fetuses showed a complete atrioventricular block, two an atrial flutter, nine ventricular extrasystole, and one a complete irregular heart rate. Five fetuses were suspected to have a congenital heart defect. In all cases magnetocardiograms were recorded. Results Nine fetuses with extrasystole showed a range of premature atrial contractions, premature junctional beats or premature ventricular contractions. Two fetuses with atrial flutter showed typical flutter waves and four fetuses with complete atrioventricular block showed an uncoupling of P-wave and QRS complex. One fetus showed a pattern suggestive of a bundle branch block. In three of four fetuses with confirmed congenital heart defects the magnetocardiogram showed abnormalities. Conclusion Fetal magnetocardiography allows an insight into the electrophysiological aspects of the fetal heart, is accurate in the classification of fetal arrhythmias, and shows potential as a tool in defining a population at risk for congenital heart defects.

Atrial Fibrillation Induction and Ablation. Introduction: The low frequency of spontaneous premature atrial contractions (PACs) may be an impediment to mapping and ablation of atrial fibrillation (AF). It has been shown that PACs following external or internal cardioversion of AF can initiate AF. If this method could reproducibly induce PACs from the same location as spontaneous PACs, it would be clinically significant. High-resolution noncontact mapping can map a single beat, should help identify the sites of spontaneously occurring PACs and PACs induced following cardioversion of spontaneous or induced AF, and could help correlate the trigger sites for AF induction. Methods and Results: Twelve patients (8 men and 4 women; mean age 49 ± 10 years) with spontaneous PACs were included in the study. In all patients, AF was induced and subsequently cardioverted to assess and map isolated PACs or PACs that induced AF. Using the EnSite 3000 noncontact mapping system, mapping was performed of spontaneously occurring isolated PACs and PACs that induced AF and PACs (both with and without AF) that occurred on at least two different occasions following cardioversion. The locations of the spontaneous and the induced PACs were similar; 97% of induced PACs came from the same locations as those of spontaneous PACs (P = 0.5). Radiofrequency lesions guided by this mapping technique were delivered at 14 pulmonary vein sites. Following a single ablation attempt during a mean follow-up of 19 ± 4 weeks, 42% of the patients were in sinus rhythm and drug-free, whereas an additional 24% of patients could be maintained in sinus rhythm on drugs that had failed before. Conclusion: There is a high degree of correlation between spontaneous and induced PACs as the trigger sites for AF initiation. Cardioversion of spontaneous or induced AF could be used as an electrophysiologic parameter for guiding therapy.

MIYAMOTO, K.-J., et al.: Studies on the Prevalence of Complicated Atrial Arrhythmias, Flutter, and Fibrillation in Patients with Reciprocating Supraventricular Tachycardia Before and After Successful Catheter Ablation. Atrial flutter and AF are complications in approximately 30% of cases of paroxysmal supraventricular tachycardia (PSVT)-indicated catheter ablation, and it is of interest to determine if therapeutic modification for PSVT would eliminate combined atrial tachyarrhythmia like atrial flutter and AF. The aim of this study was to determine the incidence and the risk of atrial tachyarrhythmias after catheter ablation of PSVT. A total of 152 patients (age range 12–74, mean 41 ± 17 years) with accessory pathway (n = 106) and/or dual atrioventricular nodal conduction (n = 46) were enrolled in a 2-year follow-up program after successful catheter ablation. Possible risks on clinical background (age, sex, PSVT duration, hemodynamic instability during attacks), premature atrial contraction (PACs) on Holter monitoring, echocardiographic left atrial size, and electrophysiological property (insertion site, conduction type, effective refractory period) were evaluated. Atrial flutter and AF were complications in 53 (35%) of the subjects, who were elderly and had a longer PSVT history with a larger left atrial dimension and frequent PACs; however, the electrophysiological properties were similar. After a 2-year follow-up period 36 (24%) of the patients still exhibited PAC runs, including 13 (9%) with atrial flutter and AF, each one of whom were complicated with nonlethal cerebral thromboembolism and congestive heart failure. Multiple-logistic-regression analysis revealed that advanced age (≥ 41 years, P = 0.0152) and frequent PACs (≥ 1% of total daily QRS counts, P = 0.0426) on Holter monitoring are the risk factors of PAC runs and/or atrial flutter and AF. In conclusion, successful ablation for PSVT is thought to be beneficial for preventing atrial flutter and AF. However, careful follow-up to monitor for the recurrence and atrial flutter and AF related complications, especially in patients of solitary atrial flutter and AF without reciprocating tachycardia and with frequent PAC.

Extrasystoles particularly premature atrial contractions noted during labour on the fetal heart rate monitoring strip are usually thought to be benign. In pregnancies complicated by fetal infection and/or the fetal inflammatory response syndrome, there are some data that extrasystoles noted during the intrapartum period may be related to neonatal sepsis and eventual poor neonatal outcome including death or neonatal encephalopathy. Additional observations are needed to substantiate this hypothesis.

Ablation of Atrial Fibrillation. Introduction: The origin of double potentials inside the left superior pulmonary vein and their relation to the mechanisms of idiopathic paroxysmal focal atrial fibrillation (AF) are unclear. Methods and Results: A total of 40 patients were studied. Group I included 15 patients who underwent radiofrequency catheter ablation of accessory pathway. Double potentials were found inside the left superior pulmonary vein during sinus rhythm in 10 patients and during premature atrial contractions in the remaining five patients. Group II included 25 patients with idiopathic paroxysmal AF. Double potentials were also identified in the left superior pulmonary vein. In 15 patients (Group IIA), the earliest automatic discharge during premature atrial contractions and at the onset of AF was within the left superior pulmonary vein. AF was ablated by radiofrequency energy application at the site registering double potentials. Radiofrequency ablation in the remaining 10 patients failed to terminate AF (Group IIB). The patients in Group UA had significantly more male patients and more frequent premature atrial contractions and atrial tachycardia on 24-hour Holter recordings prior to the procedure than patients in Group IIB. Conclusions: Double potentials are present at the left superior pulmonary veins in patients with and without a history of AF. The first potential is due to the activation of atrial myocardium and the second is due to the activation of a different muscular structure. Rapid discharge of this structure triggers episodes of paroxysmal AF. Patients with focal AF originating from the left superior pulmonary vein can be identified by Holter recordings.

The methods used for preventing endless-loop tachycardias (ELTs) most often consist of initiating a long postventricular atrial refractory period (PVARP) with the sensing of every event likely to induce ELTs, such as sensed premature ventricular contractions (PVCs). A new fallback function may be useful to prevent the initiation of ELTs. A window of atrial rate acceleration detection (WARAD) is initiated with the sensing of every sinus event and equals 75% of the preceding PP interval. If an atrial event is sensed during this period, as are premature atrial contractions (PACs), no atrioventricular (AV) delay is initiated, but an atrial pulse output is delivered and a subsequent 31-msec AV delay is started. Theoretically retrograde P waves are premature compared to sinus rhythm. They are therefore detected as PACs, and do not initiate AV delay, thus prohibiting the induction of ELTs. This function was tested in six patients, using external or implanted Chorus 2 pacemakers. Short PVARP (203 msec) and high atrial sensibility were programmed. Retrograde conduction was induced either by inefficient atrial pacing or a long programmed AV delay. Two different dual chamber settings were tested: dual chamber pacing with the fallback function On or Off. In every situation, the function proved effective in preventing ELTs: the number of tachycardia episodes went from 124 with the function programmed Off to 5 with the function programmed On for comparable durations. More than 75 ELTs effectively prevented by fallback have been recorded.

A 68-year-old man presented with congestive heart failure (NYHA III) with QRS morphology of left bundle branch block. Systemic amyloidosis with cardiac involvement was pointed out 7 years ago. A Medtronic CRT-D device was implanted because of dyssynchronous left ventricular motion. Four months after implantation, the patient had recurrent episodes of faintness during exercise. Faintness was coincident with sudden prolongation of a P-P interval from 600 ms to 1100 ms at the peak exercise. It was due to sinus pause followed by a back-up pacing of nonrate responsive DDD pacing at 60/min with rate adaptive AV delay (280 ms to 180 ms). The pacing parameters were changed so that the symptom was resolved. Sixteen months later, the patient developed general fatigue during exercise. Exercise intolerance was apparently due to bi-ventricular pacing failure, but this was not shown at rest. Intra-cardiac ECG during exercise showed a premature atrial contraction and/or a non-competitive atrial pacing (NCAP) within post-ventricular atrial refractory period (PVARP), followed by aborted ventricular pacing. Conducted own QRS appeared to resume ventricular dyssynchrony. Symptom was improved after NCAP was turned off and PVARP was shortened. This case is unique because of exercise-induced loss of bi-ventricular pacing, which was not due to shortening of own AV conduction. It was useful to examine intra-cardiac ECG during exercise in detail.

Introduction: The endpoint of electrical pulmonary vein (PV) isolation is the agreed goal of procedures targeting the PV-left atrial junction in paroxysmal atrial fibrillation (AF). On the other hand, the targets and endpoints of ablation for chronic (persistent and long-lasting) AF are ill-defined. Results: A 69-year-old male with long-lasting AF was referred for catheter ablation. We performed complex fractionated atrial electrogram (CFAE) guided catheter ablation for AF. AF spontaneously terminated after CFAE guided catheter ablation. After which, frequent premature atrial contractions (PACs) occurred and were mapped and successfully ablated. Our endpoint of CFAE guided catheter ablation in patients with chronic AF used to AF termination. Recently, we use isoproterenol (ISP) to induce AF after AF termination even if AF is non-paroxysmal. Isthmus dependent atrial flutter (AFL) was induced by ISP in this case. AFL was terminated by TV-IVC linear ablation. Repeat induction with rapid atrial pacing and high dose ISP failed to re-induce any atrial tachyarrhythmias. This patient remains in sinus rhythm without any atrial arrhythmia recurrent >7 months after this procedure. Conclusions: Repeat AF induction after AF termination during CFAE guided ablation may be useful to unmask remaining atrial tachyarrhythmia substrate which could be successfully ablated and could help minimizing a chance for a redo procedure in patients with long-lasting AF.

Background: Paroxysmal atrial fibrillation (AF) is highly prevalent in patients with ischemic stroke, but the diagnosis is often difficult. Methods: This study consisted of 61 stroke patients in sinus rhythm without a history of paroxysmal AF. All patients underwent P-wave signal-averaged electrocardiography (P-SAECG), echocardiography, 24-hour Holter monitoring, and measurement of plasma B-type natriuretic peptide (BNP) concentrations at admission. Results: An abnormal P-SAECG was found in 33 of 61 stroke patients. In the follow-up period of 11±3 months, paroxysmal AF developed in 19 patients (AF group). The remaining 42 patients were divided into non-AF group. An abnormal P-SAECG and frequent premature atrial contractions (PACs, 100 or more/24 hour) were detected more frequently in patients with AF group than non-AF group (89.5% vs 35.7%; p