Sinus Rhythm ECG Research Articles

“Classical” Response in a Pre-excited Tachycardia

A 24-year-old patient presented with history of recurrent palpitation and was diagnosed as wide QRS tachycardia which was cardioverted. The sinus rhythm ECG and the tachycardia ECG are shown in Figure 1. During the electrophysiological study, 2 morphologies of tachycardia were inducible, 1 with right bundle branch block (RBBB) morphology (Figure 2A) and another with left bundle branch block (LBBB) morphology (Figure 2B), which was her clinical tachycardia. The LBBB type wide QRS tachycardia was faster (Figure 2B). During the RBBB morphology tachycardia, ventricular entrainment showed a V–A–V response and a His refractory ventricular extrastimulation advanced the retrograde atrial activation, resetting the tachycardia. Figure 1. Twelve-lead electrocardiograms of the patient in sinus rhythm ( A ) and during clinical tachycardia ( B ). Figure 2. Surface leads I, III, and V1 and intracardiac electrograms from right atrium (HALO 1, 2 at lateral right atrium to HALO 17, 18), His bundle (His bundle distal [HBED] and His bundle middle [HBEm]), the coronary sinus (coronary sinus distal [CSD] and coronary sinus proximal [CSP]) and right ventricular apex (RVA). A , The orthodromic tachycardia with right bundle branch block aberrancy. B , The left bundle branch block tachycardia of shorter cycle length and long ventricular–His of 80 ms with the same retrograde eccentric atrial activation as in the initial tachycardia. The LBBB morphology tachycardia showed variation in cycle length with a constant Ventriculo–Atrial (VA) interval. Atrial entrainment did not change the QRS morphology or VA relationship. An early premature atrial extrastimulation from the lateral right atrium showed an interesting finding (Figure 3). Very late atrial extrastimulus from the same location did not advance the V without affecting the septal A. What are the mechanisms of the two tachycardia? Figure 3. Surface leads I, III, and V1 and intracardiac electrograms from right atrium (HALO 1, 2 at lateral right atrium to HALO …

Ventricular Tachycardia in a Patient with Repaired Tetralogy of Fallot

We report a 22 year old male presenting to the emergency department with a symptomatic wide complex tachycardia. We discuss the algorithms to determine the origin of the tachycardia, and we analyzed in detail his 12- lead ECG in sinus rhythm. Most frequent ECG patterns in repaired tetralogy of Fallot are also discussed.

Increased Variability of Tpeak-Tend Area Predicts Sudden Cardiac Death in Competing Risk Analysis in Heart Failure Patients with Ejection Fraction above and below 35%

Background Repolarization lability precedes ventricular arrhythmias. However, in recent competing risk analysis QT variability index predicted non–sudden cardiac death (SCD) but did not predict SCD. Predictive values of other repolarization lability parameters have not been studied in competing risk analysis. Methods We analyzed 3 minutes of baseline resting orthogonal ECGs in sinus rhythm in 533 participants of the observational cohort heart failure (HF) study (mean age 63.1 ± 11.7; males 70.6%; left ventricular ejection fraction [LVEF] >35% in 254 [48%]). Repolarization lability was measured as the root mean square successive difference (rMSSD) of the area under the curve from T-peak to T-end series (TpTe Area rMSSD). Holter monitoring was performed to identify patients who presented frequent (>240 in 24 hours) ventricular premature beats and also nonsustained ventricular tachycardia (NSVT). SCD and non-SCD served as primary endpoints. Results During median follow-up of 3.7 years of, 116 patients died, 52 from SCD and 53 from non-SCD. In multivariate competing risk analyses after adjustment for EF, New York Heart Association HF class, NSVT, and frequent premature ventricular complexes on 24-hours Holter ECG, the highest Tpeak-Tend Area rMSSD quartile was associated with SCD [subhazard ratio: 1.79 (95% CI 1.05–3.06), P = .034] but did not predict non-SCD [subhazard ratio: 0.95 (95% CI 0.53-1.72), P = .875; Figure 1). No interaction between Tpeak-Tend Area rMSSD and LVEF was found. Conclusions Increased repolarization lability measured as Tpeak-Tend area variability predicts SCD but not non-SCD in HF across the continuum of LV dysfunction.

Rare Forms of Preexcitation

A 16-year-old boy was brought to the hospital when he complained of chest pain while at a basketball game. In the emergency room, he was noted to have a wide complex tachycardia. The ECG at presentation is shown in Figure 1. He was cardioverted after administration of 150 mg of intravenous amiodarone. His ECG after cardioversion is shown in Figure 2. His physical examination and developmental evaluation were significant for obesity, synophrys, mild fifth digit clinodactyly, and subnormal intelligence. Cardiac magnetic resonance imaging with contrast showed massive left ventricular hypertrophy (LVH), with preserved ejection fraction, and several areas of delayed hyperenhancement in the subendocardium. Cardiac catheterization showed no obstructive coronary artery disease or anomalous coronary arteries. What are the diagnostic considerations for this constellation of findings of massive LVH, subendocardial necrosis, and abnormal ECGs? Figure 1. Wide complex tachycardia at presentation. Figure 2. Sinus rhythm ECG showing ventricular preexcitation and normal axis (see text for further details). The ECG in Figure 1 displays a wide complex tachycardia, with a right-bundle branch block morphology with a QRS complex duration >120 ms. A wide complex tachycardia with a right-bundle branch block morphology could be secondary to ventricular tachycardia originating from the left ventricle or a preexcited tachycardia in the presence of a left-sided bypass tract. However, the QS complex in lead V6 rules out a left-sided atrioventricular bypass tract, because such bypass tracts do not have the left ventricle apex as their ventricular insertion site, which is necessary to produce a QS complex in V6. A left-sided nodofascicular bypass tract with insertion in the distal His-Purkinje system can produce QS complexes in lead V6, but these are extraordinarily rare and occur more frequently on the right side. Initial R wave in lead aVR,1 a QS complex in lead …

Heart rate recovery index in patients with psoriasis.

In clinical practice, autonomic functions are indirectly investigated with heart rate recovery (HRR) index measurements. Our aim was to evaluate the HRR index in patients with psoriasis, which is a systemic inflammatory disease. The study population included 39 psoriasis patients (18 female, mean age 48±15 years) and 40 control group (18 female, mean age 44±9 years) healthy individuals. The severity of psoriasis was calculated using the psoriasis area and severity index (PASI). None of the study patients had a PASI score >50. All of the participants underwent treadmill exercise testing using the Bruce protocol. According to basic clinical and demographic characteristics, both groups were similar with regard to age, body mass index, and fasting glucose and cholesterol levels. No significant differences were observed in the systolic or diastolic blood pressures or resting heart rates between the two groups. All patients and control-group participants had sinus rhythm and normal 12-lead ECG results at rest. All subjects completed the exercise tests to exhaustion without rhythm abnormalities, ischemic changes, or other complications. The maximal heart rate and metabolic equivalents achieved during the exercise stress test (EST) were similar in the psoriasis and control group (163±16 vs. 170±16, p=0.07; 9.8±0.9 vs. 10.1±1.0, p=0.24, respectively). The 1st, 3rd, and 5th minute HRR indices of patients with psoriasis were similar to those of the control group (HRR1: 30±12, 32±18, p=0.71; HRR3: 57±13, 64±17, p=0.10; HRR5: 64±15, 68±16, p=0.46, respectively). The HRR index, which is calculated by an EST and associated with autonomic nervous system function, is not effected in mild to moderate psoriasis patients.

347 Is electrophysiological study required in children with spontaneous supraventricular tachycardia and normal ECG in sinus rhythm?

347 Is electrophysiological study required in children with spontaneous supraventricular tachycardia and normal ECG in sinus rhythm?

Missing diagnosis of preexcitation syndrome on ECG: Clinical and electrophysiological significance

Electrocardiographic criteria of preexcitation syndrome are sometimes not visible on ECG in sinus rhythm (SR). The purpose of the study was to evaluate the significance of unapparent preexcitation syndrome in SR, when overt conduction through accessory pathway (AP) was noted at atrial pacing. MethodsAnterograde conduction through atrioventricular AP was identified at electrophysiological study (EPS) in 712 patients, studied for tachycardia (n=316), syncope (n=89) or life-threatening arrhythmia (n=55) or asymptomatic preexcitation syndrome (n=252). ECG in SR at the time of EPS was analysed. Results78 patients (11%) (group I) had a normal ECG in SR and anterograde conduction over AP at atrial pacing; 634 (group II) had overt preexcitation in SR. Group I was as frequently asymptomatic (35%) as group II (35%), had as frequently tachycardias, syncope or life-threatening arrhythmia as group II (43, 5, 2% vs 43, 13, 8%). AP was more frequently left lateral in group I (57%) than in group II (36%)(p<0.001). AV re-entrant tachycardia, atrial fibrillation (AF), antidromic tachycardia were induced as frequently in group I (54, 18, 10%) as in group II (54, 27, 7%). Malignant forms (induced AF with RR intervals between preexcited beats <250ms in control state or <200ms after isoproterenol) were as frequent in group I (11.5%) as II (14%). ConclusionsThe frequency of unapparent preexcitation syndrome represents 11% of our population with anterograde conduction through an AP and could be underestimated. The risk to have a malignant form is as high as in patients with overt preexcitation syndrome in SR.

T-WAVE ALTERNANS AND ST DEPRESSION ASSESSMENT IDENTIFIES LOW RISK INDIVIDUALS WITH ISCHEMIC CARDIOMYOPATHY IN THE ABSENCE OF LEFT VENTRICULAR HYPERTROPHY

Background Although ECG left ventricular hypertrophy (LVH) by Cornell product (CP) predicts increased mortality in patients with ischemic cardiomyopathy (ICM), those without CP LVH remain at relatively high risk. We examined whether T-wave alternans (TWA) testing and ST depression can improve risk stratification in these patients. Methods and Results This study examined 317 patients with ICM, nonsustained ventricular tachycardia, and a resting ECG in sinus rhythm, who presented for electrophysiology and TWA testing, and potential implantable cardioverter defibrillator (ICD) implantation. LVH was defined by CP :[(RaVL + SV3) +6 mm in women] × QRS duration > 2440 mm * msec. ST depression was examined as a categorical variable using an established threshold of depression of ≥50 μV in V5 or V6. In Cox multivariate models, abnormal TWA testing and ST depression were independent predictors of mortality in patients without CP LVH (HR 2.52, CI 1.09–5.80, P = 0.030 and HR 2.87, CI 1.41–5.81, P = 0.004, respectively). Individuals with no LVH by CP, normal TWA, and no significant ST depression, comprised 23% of the study population and had a 5.6% 3-year mortality, compared to an overall 20% mortality. Conclusions TWA and ST depression testing are strong predictors of mortality among ICM patients without CP LVH, with normal testing conversely predicting low 3-year mortality. Thus, risk assessment with TWA testing and a resting ECG can identify ICM patients at low risk who may be less likely to benefit from ICD implantation.

Effectiveness of Cardiac Resynchronization Therapy by QRS Morphology in the Multicenter Automatic Defibrillator Implantation Trial–Cardiac Resynchronization Therapy (MADIT-CRT)

This study aimed to determine whether QRS morphology identifies patients who benefit from cardiac resynchronization therapy with a defibrillator (CRT-D) and whether it influences the risk of primary and secondary end points in patients enrolled in the Multicenter Automatic Defibrillator Implantation Trial-Cardiac Resynchronization Therapy (MADIT-CRT) trial. Baseline 12-lead ECGs were evaluated with regard to QRS morphology. Heart failure event or death was the primary end point of the trial. Death, heart failure event, ventricular tachycardia, and ventricular fibrillation were secondary end points. Among 1817 patients with available sinus rhythm ECGs at baseline, there were 1281 (70%) with left bundle-branch block (LBBB), 228 (13%) with right bundle-branch block, and 308 (17%) with nonspecific intraventricular conduction disturbances. The latter 2 groups were defined as non-LBBB groups. Hazard ratios for the primary end point for comparisons of CRT-D patients versus patients who only received an implantable cardioverter defibrillator (ICD) were significantly (P < 0.001) lower in LBBB patients (0.47; P < 0.001) than in non-LBBB patients (1.24; P = 0.257). The risk of ventricular tachycardia, ventricular fibrillation, or death was decreased significantly in CRT-D patients with LBBB but not in non-LBBB patients. Echocardiographic parameters showed significantly (P < 0.001) greater reduction in left ventricular volumes and increase in ejection fraction with CRT-D in LBBB than in non-LBBB patients. Heart failure patients with New York Heart Association class I or II and ejection fraction ≤ 30% and LBBB derive substantial clinical benefit from CRT-D: a reduction in heart failure progression and a reduction in the risk of ventricular tachyarrhythmias. No clinical benefit was observed in patients with a non-LBBB QRS pattern (right bundle-branch block or intraventricular conduction disturbances). URL: http://www.clinicaltrials.gov. Unique identifier: NCT00180271.

308 Are there indications for supraventricular re-entrant tachycardia in the youth?

Radiofrequency (RF) ablation of paroxysmal supraventricular tachycardia (SVT) that could be an atrioventricular node re-entrant tachycardia (AVNRT) or AV reentrant tachycardia (AVRT) through a concealed accessory pathway (AP) is widely used in adults, but the indications remain controversed in children and teenagers. The purpose of the study was to evaluate the clinical and electrophysiological factors of indications of AVNRT and AVRT ablation in the youth and the results of the procedure. 66 children or teenagers aged from 6 to 18 years (15 ± 2) among 1099 patients consecutively recruited for SVT; they had a normal ECG in sinus rhythm; AVNRT or AVRT was confirmed at electrophysiological study (EPS). Patients with anterograde conduction through an AP were excluded. RF ablation was indicated in 26 children or teenagers (39%) (group I) significantly less frequently than in adults (668/1033; 65%) (p < 0.0000). 40 other children were not treated or received beta blockers (group II). Group I and II have the same age (15 ± 2.6 vs 15 ± 2.8). Male gender tended to be less frequent in group I (9/26; 35%) than in group II (20/40; 50%) (NS, 0.2). At EPS, group I had more frequently a concealed AP (13/26; 50%) than group II (8/40; 20%) (p < 0.01). The incidence of concealed AP in group I is higher than in adults (102 of 668 procedures;15%) (p < 000000). In remaining children, ablation of slow pathway was performed in 13 children. There were no complications, but failures or reappearances of SVT after ablation were frequent (6/26; 23%), more frequent in AVRT (4/13) than in AVNRT (2/13) (NS) and were related to the age (12.7 ± 3 vs 16 ± 2; p < 0.002). They tended to be more frequent than in adults (77/668; 11.5%) (p < 0.07). In group II, 3 children continue the beta blockers and other children are not treated. The indications of slow pathway remain rare in children. Most of the indications of SVT ablation in the youth which are rare, concern generally the children and teenagers with concealed AP. The results are almost as good as in adults, mainly for the slow pathway ablation and in teenagers.

182 History of stroke in patients with paroxysmal supraventricular tachycardia. clinical significance

Atrial fibrillation (AF) is a major cause of embolic event, but the significance of other arrhythmias remains unknown. The purpose of study was to assess the significance of unexplained stroke in patients who had apparently only supraventricular tachycardia (SVT). Unexplained stroke was noted in 26 patients (pts) (group I) admitted for palpitations and electrophysiological study (EPS); they were issued from a population of 1002 pts with normal ECG in sinus rhythm, palpitations or tachycardia and with inducible SVT at EPS; 976 pts had no history of stroke (group II). EPS consisted of atrial pacing and programmed atrial stimulation in control state and if necessary after infusion of isoproterenol. Clinical and electrophysiological data of both groups were studied. Pts with stroke had a normal carotid ultrasound study and transcranial Doppler ultrasonography. Pts with unexplained stroke represent 2.5% of population with SVT. They were older than remaining pts without stroke (65±10 vs 50±19 years) (p 0.001). They have more frequently associated heart disease (8/26, 31% vs 37/976, 4%) (p < 0.001). Male gender was more frequent in group I (16/26, 60%) than in group II (355/956, 37%) (p< 0.05). Typical AV node re-entrant tachycardia was noted in 17 group I pts (65%) and 693/976 (68%) (NS); AV re-entrant tachycardia associated with a concealed accessory pathway was noted in 2 group I pts (8%) and 168 group I pts (17%) (NS); atypical AV node re-entrant tachycardia was more frequent in group I (7/26, 27%) than in group II (115/976, 12%) (p<0.05). AF induction was more frequent in group I (6/26, 23%) than in group II (35/976, 3.5%) (p< 0.001). Ablation was performed in 6 group I pts; one of them died from another stroke; another one died suddenly; another one developed a permanent AF. Old age, male gender, associated heart disease, and induction of atrial fibrillation were significant factors associated with the history of stroke in pts with SVT. They have a risk of adverse events during the follow-up. However, unexplained stroke was a rare event in patients with paroxysmal SVT, noted in 2.5% of this population.

Abstract 5128: Incidence of Stroke Among Patients With Paroxysmal Supraventricular Tachycardia

Background : Atrial fibrillation (AF) is a major cause of embolic event, but the significance of other arrhythmias remains unknown. The purpose of study was to assess the significance of unexplained stroke in patients who had apparently only supraventricular tachycardia (SVT). Population : Unexplained stroke was noted in 27 patients (group I) admitted for palpitations and electrophysiological study (EPS); they were issued from a population of 1007 patients with normal ECG in sinus rhythm, palpitations or tachycardia and with inducible SVT at EPS; 980 pts had no history of stroke (group II). Methods : EPS consisted of atrial pacing and programmed atrial stimulation in control state and if necessary after infusion of isoproterenol. Clinical and electrophysiological data of both groups were studied. Patients with stroke had a normal carotid ultrasound study and transcranial Doppler ultrasonography. Results : Patients with unexplained stroke represent 2.6 % of population with SVT. They were older than remaining patients without stroke (65±10 vs 50±19 years) (0.001). They have more frequently associated heart disease (8/27, 30 % vs 37/980, 4 %) (p &lt; 0.001). Male gender was more frequent in group I (16/27, 59 %) than in group II (361/980, 37 %) (p&lt; 0.05). Typical AV node re-entrant tachycardia was noted in 17 group I patients (65 %) and 695 group II patients (68 %) (NS); AV re-entrant tachycardia associated with a concealed accessory pathway was noted in 2 group I patients (7 %) and 169 group II patients (17 %) (NS); atypical AV node re-entrant tachycardia was more frequent in group I (7/27, 26 %) than in group II (115/980, 12 %) (p&lt;0.05). AF induction was more frequent in group I (7/27, 26 %) than in group II (36/980, 4 %) (p&lt; 0.001). Ablation was performed in 6 group I patients; one of them died from another stroke; another one died suddenly; another one developed a permanent AF. Conclusions : Unexplained stroke was a rare event in patients with paroxysmal SVT, noted in 2.6 % of this population. Old age, male gender, associated heart disease, and induction of atrial fibrillation were significant factors associated with the history of stroke in patients with SVT. They have a risk of adverse events during the follow-up.

Comparaison des sujets ayant des tachycardies jonctionnelles paroxystiques et des syncopes avec des sujets sans syncopes

Introduction The purpose of the study was to determine the possible mechanisms of presyncope in patients who have paroxysmal junctional tachycardias (PJT) and a normal surface ECG between tachycardias. Methods Among 419 patients consecutively recruited for PJT, aged from 10 to 88 years (47±19), 78 of them had presented at least one syncope; they had a normal ECG in sinus rhythm. Transesophageal programmed atrial stimulation was performed using one and two atrial extrastimuli delivered in control state and if necessary after infusion of 20–30 μg of isoproterenol; arterial blood pressure was monitored; vagal maneuvers and tilt test ( n = 25) were performed; echocardiogram was systematic. Results Age, sex, method of induction, tachycardia mechanism and the mean heart rate in tachycardia were similar in patients with and without syncope. Syncope was related to a vagal reaction induced by the PJT in 31 patients, to a fast rate during PJT in 15 patients, to a sinus node dysfunction in six patients, to a coronary ischemia in five patients, to a tetany induced by PJT in three patients, to an advanced age in three patients, to multiple causes in three patients and remained unexplained in eight patients. Radiofrequency ablation of reentrant circuit, performed in 28 patients, suppressed syncope in 26 of them. Conclusion Presyncope or syncope occurred in 18% of patients who had a history of paroxysmal junctional tachycardia. Several mechanisms were implicated; the most frequent causes were coronary ischemia or sick sinus syndrome in old patients, vasovagal reaction or fast rate in tachycardia or tetany in patients of all ages.

Atrial Fibrillation–Atrial Flutter Interactions

An appreciation of the article by Moreira et al in the current issue of Circulation 1 requires an understanding of the close interrelationship between atrial fibrillation (AF) and atrial flutter (AFL). These authors have understood this interrelationship and applied it to their data to advance the approach to both AF and AFL ablation. Key to this understanding is the recognition that cavotricuspid isthmus (CTI)–dependent AFL almost always develops from antecedent AF of variable duration.2–5 This is because in almost all instances, it is during the AF that a functional line of block (LoB) necessary for the development of AFL forms between the superior and inferior vena cavae. This LoB acts as a critical lateral boundary that prevents short-circuiting of the AFL reentrant circuit. Thus, in the vast majority of instances, without preceding AF, there can be no AFL. The most recent additional support of this concept comes from the report by Ellis et al,6 which found that of 363 patients who presented with only CTI-dependent AFL and who underwent CTI ablation, long-term follow-up (mean of 39±11 months) demonstrated newly recognized AF in 82%. It also should be noted that, as Moreira et al1 recognize, in some patients, a LoB between the vena cavae may be fixed (ie, anatomic) rather than functional. In such patients, AF may not be required for AFL to develop. Article p 2786 As Moreira et al1 further recognize, their report does not answer all the questions about the interrelationships of AF and AFL as they relate to AF ablation, …

Intracardiac Correlate of the Epsilon Wave in a Patient With Arrhythmogenic Right Ventricular Dysplasia

A 29-year-old man with no significant past medical history presented to the emergency department of a local hospital with complaints of dyspnea and palpitations. A 12-lead ECG was obtained, revealing a wide complex tachycardia (QRS duration 160 ms) at a rate of 196 beats per minute with a right bundle-branch block morphology and left axis deviation. In the emergency department, the ECG was thought to represent supraventricular tachycardia, and the patient was given adenosine and diltiazem intravenously. This did not terminate or change the rate of the tachycardia. He was then given metoprolol 5 mg intravenously, and the tachycardia slowed and terminated. A 12-lead ECG in normal sinus rhythm is shown (Figure 1). Figure 1. Twelve-lead ECG in normal sinus rhythm. The findings include right atrial abnormality, normal QRS axis, anteroseptal Q waves, and precordial T-wave inversions. The most striking finding is the presence of an epsilon wave (black arrow) in V1 and V2. A …

Catheter Ablation for Ventricular Tachycardia

Sustained ventricular tachycardia (VT) is an important cause of morbidity and sudden death in patients with heart disease.1 Implantable cardioverter-defibrillators (ICDs) terminate VT episodes, reducing the risk of sudden death. Recurrent VT develops in 40% to 60% of patients who receive an ICD after an episode of spontaneous sustained VT. A first episode of VT occurs in ≈20% of patients within 3 to 5 years after ICD implantation for primary prevention of sudden death in high-risk groups.2–4 ICD shocks reduce quality of life and are associated with an increased risk of death.2–4 Antiarrhythmic drug therapy with amiodarone or sotalol reduces VT episodes but with disappointing incidence of side effects and efficacy.2 Catheter ablation is useful for reducing VT episodes and can be life-saving when VT is incessant.1,5,6 Idiopathic VTs occur in patients without structural heart disease and rarely cause sudden death. Electrophysiological study with catheter ablation is often warranted to confirm the diagnosis, to provide further evidence for the absence of ventricular scar or other disease, and often to cure the arrhythmia. Ablation is also an option for symptomatic nonsustained VT and frequent ventricular ectopy in these patients.1 The appearance of the VT on ECG often suggests its likely cause and associated heart disease (Figure 1). Monomorphic VT has the same QRS complex from beat to beat, indicating repetitive ventricular activation from a structural substrate or focus that can be targeted for ablation. Most are due to reentry through regions of ventricular scar.7 Figure 1. ECG types of VT and most common causes are shown with characteristic ECG features of selected VTs. LBBB indicates left bundle-branch block; LVOT, LV outflow tract; RBBB, right bundle-branch block; L, left; and R, right. Polymorphic VTs have a changing ventricular activation sequence that can be due to …

Atrial fibrillation classification with artificial neural networks

The acquired 72 normal sinus rhythm ECGs and 80 ECGs with atrial fibrillation (AF) are decomposed with ‘db10’ Daebauchies wavelets at level 6 and power spectral density was calculated for each decomposed signal with Welch method. Average power spectral density was calculated for six subbands and normalized to be used as input to the neural network. Levenberg–Marquart backpropagation feed forward neural network was built from logarithmic sigmoid transfer functions in three-layer form. The trained network was tested on 24 normal and 28 AF state ECGs. The classification performance was accomplished as 100% accurate.

WPW cases in the literature prior to the publication of Wolff, Parkinson and White in 1930

In 1930, Wolff, Parkinson and White described the clinical entity of what is today known as the preexcitation or WPW syndrome. In the preceding literature, the authors found four comparable cases. Later on, seven further cases published prior to 1930 were discovered. An analysis of the altogether eleven cases displays that, in addition to the anomalous ECG in sinus rhythm, nearly all typical electrocardiographic findings during the tachyarrhythmias are found in this early literature. As tachycardia ECGs especially help to understand the mechanism of the WPW syndrome, the question is discussed whether already Wolff, Parkinson and White would have been able to give the correct interpretation of the mechanism if they had taken into consideration their own tachycardia ECGs as well as those known to them from the literature.

Radiofrequency Catheter Ablation of Accessory Pathway in a Patient with Ebstein’s Anomaly and Atrial Septal Defect

The authors report the case of a 57-year-old woman with Ebstein's anomaly and atrial septal defect. She was referred to their hospital for treatment of refractory paroxysmal wide QRS tachycardia. Her 12-leads ECG in sinus rhythm showed ventricular preexcitation of type B Wolff-Parkinson-White syndrome. In a baseline electrophysiological study, a wide QRS tachycardia with right bundle branch block configurations was induced. This tachycardia was orthodromic atrioventricular reciprocating tachycardia with a right inferior accessory pathway. Radiofrequency current was successfully delivered at the inferior site of the atrialized right ventricle. Radiofrequency catheter ablation seems to be useful for supraventricular tachycardia in patients with Ebstein's anomaly and atrial septal defect.

Electrocardiogram in patients with fasciculoventricular pathways: A comparative study with anteroseptal and midseptal accessory pathways

The purpose of this study was to describe the ECG profile of a cohort of patients with fasciculoventricular pathways and compare the profile with the ECG of patients with anteroseptal and midseptal accessory pathways. Electrophysiologic findings suggest fasciculoventricular pathways insert into the septal region. Findings also suggest the 12-lead surface ECG during sinus rhythm is similar to the ECG of patients with anteroseptal and midseptal bypass tracts. Four different observers analyzed the 12-lead ECG of seven patients with fasciculoventricular pathways (group I) and the ECG of 20 patients with midseptal AV accessory pathways (group II) and 20 patients with anteroseptal AV accessory pathways (group III). The following variables were analyzed: ECG frontal plane QRS and delta wave axis; angle between the QRS and the delta wave axis; QRS width; R/S ratio in lead III; presence of a negative delta wave in inferior leads; and precordial lead transition to R/S >1. The ECG of fasciculoventricular pathways shows a variable pattern. It shares some features with an anteroseptal accessory pathway and others with a midseptal accessory pathway. A narrower QRS width was the most important variable in distinguishing a fasciculoventricular pathway from a septally located AV bypass tract (P <.0001). The angle between the QRS and the delta wave frontal plane axis could differentiate a fasciculoventricular pathway from an anteroseptal bypass tract (P <.0001) but not from a midseptal accessory pathway. The sinus rhythm ECG of patients with fasciculoventricular pathways shows similarities with ECGs of patients with anteroseptal and midseptal accessory pathways, but the QRS complex usually is narrower. The ECG recorded during sinus rhythm cannot reliably differentiate fasciculoventricular pathways with a broad QRS complex from anteroseptal or midseptal bypass tracts.