bluuebunny/crossref_metadata_2025 huggingface dataset:
Simple Electrocardiographic Criteria for Identifying the Site of Origin of Focal Right Atrial Tachycardia
Authors: TADA HIROSHI , NOGAMI AKIHIKO , NAITO SHIGETO , SUGUTA MASAHIKO , NAKATSUGAWA MASATOSHI , HORIE YASUTO , TOMITA TOMOYUKI , HOSHIZAKI HIROSHI , OSHIMA SHIGERU , TANIGUCHI KOICHI
Published: July 2006

To construct an algorithm for identifying the precise site of origin of focal right atrial tachycardia (RAT), we analyzed the P wave configuration in 32 patients with RAT who underwent successful radiofrequency catheter ablation. The RA was divided into three areas in the left anterior oblique view: superolateral, inferolateral, and inferomedial. There were 17 RATs arising from the crista terminalis (CT‐AT), 12 from the tricuspid annulus (TA‐AT), and 3 from the septum away from the TA (Sep‐AT). A negative P wave in lead aVR identified CT‐AT with a sensitivity (sens) of 100% and a specificity (spec) of 93%. In CT‐AT's, positive P waves in the inferior leads differentiated superolateral AT from inferolateral A T with a sens of 86% and a spec of 100%. In any type of AT with inferomedial or inferolateral foci, the P wave deflections in at least one of the inferior leads was negative, and negative P waves in leads V5 and V6 identified inferomedial AT with a sens of 92% and a spec of 100%. In ATs near the apex of Koch's triangle, the P wave duration in the inferior leads was shorter than during sin us rhythm. Conclusions: (1) the P wave configuration in lead aVR can easily differentiate CT‐AT from TA‐AT and Sep‐AT; (2) the P wave configuration in the inferior leads helps to determine a superior versus inferior origin in any type of AT; (3) in inferior AT, the P wave polarity in leads V5 and V6 is useful in determining a lateral versus medial origin; (4) this algorithm can predict accurately the origin of AT.
Circadian Variation in Atrial Fibrillation in Patients with Frequent Paroxysms
Authors: SOPHER S. MARK , HNATKOVA KATERINA , WAKTARE JOHAN E.P. , MURGATROYD FRANCIS D. , CAMM A. JOHN , MALIK MAREK
Published: July 2006

Determinants of the duration of episodes of atrial fibrillation (AF) in patients with paroxysmal atrial fibrillation (PAF) are poorly understood. However, autonomic tone shows circadian variation and is known to affect atrial electrophysiology. We therefore compared the duration of episodes of AF with an onset during the day (08:00 ‐ 22:00) to those with an onset during the night in a database of 24‐hour ECG recordings in patients with frequent symptomatic PAF. The heart rate in the 30 seconds prior to AF onset was also compared. From 42 recordings, 296 episodes of AF > 30 seconds duration and preceded by > 60 seconds sinus rhythm were identified. The 165 nocturnal episodes tended to be shorter (median =1.15 min) than the 131 diurnal episodes (median =1.5 min) and the distribution of nocturnal and diurnal durations was significantly different (P = 0.007; Kolgomorov‐Smirnov test). This was also true in recordings containing at least 1 diurnal and at least 1 nocturnal episode. The mean heart rate prior to AF onset was lower at night (62.2 ± 11.8 vs 75.6 ± 16.4 beats/min; P < 0.0001 Wilcoxon test). These findings suggest that in patients with frequent symptomatic PAF, autonomic influences affect the duration of episodes of AF and has pathphysiohgical and therapeutic implications.
Evolution of Changes in the Ventricular Rhythm During Paroxysmal Atrial Fibrillation
Authors: GALLAGHER MARK M. , HNATKOVA KATERINA , MURGATROYD FRANCIS D. , WAKTARE JOHAN E. P. , GUO XIAHOUA , CAMM A. JOHN , MALIK MAREK
Published: July 2006

Changes in the RR interval within episodes of paroxysmal atrial fibrillation (PAF) have not been fully characterized. A database of 177 24‐hour Holter recordings were created from patients with PAF in the CRAFT studies. PAF episodes of ≥ 1 minute duration containing ≤ 20% noise and preceded by ≥ 1 minute of sinus rhythm with ≤ 20% noise were selected. Sections of each AF episode containing 10 and 25 RR intervals were identified at the onset, middle, and termination of each episode. Descriptive characteristics (mean, SD, and RMSSD of RR intervals) were calculated within each section, and compared using a nonparametric, paired Wilcoxon test. In 25 patients (17 men, 60.6 ± 12.2 years old), 231 episodes from 44 recordings met the selection criteria. The mean RR interval increased slightly between the onset and mid‐portion of AF episodes (565.9 ± 128.3 vs 580.3 ± 144.7 ms, P < 0.001). The RR interval at the termination of AF was significantly greater than that at the start (627.1 ± 156.1 vs 565.9 ms, P < 10–11) or mid‐portion (627.1 ± 156.1 vs 580.3 ± 144.7 ms, P < 10–13). SD of the RR interval increased significantly between onset and mid‐portion (111.1 ± 60.2 vs 118.2 ± 66.7 ms, P < 0.001) and more substantially between mid‐portion and termination (118.2 ± 66.7 vs 201.8 ± 93.7 ms, P < 10–21). During paroxysms of AF, the mean RR interval and the variability of RR intervals increases. Termination of a paroxysm is preceded by a marked increase in RR interval variability.
Age and Gender Influences on Rate and Duration of Paroxysmal Atrial Fibrillation
Authors: HNATKOVA KATERINA , WAKTARE JOHAN E.P. , MURGATROYD FRANCIS D. , GUO XIAHOUA , CAMM A. JOHN , MALIK MAREK
Published: July 2006

The influence of age and gender on the character of paroxysmal atrial fibrillation (PAF) has not been described. Methods: The heart rate (HR) during PAF in patients receiving placebo or antiarrhythmic therapy was analyzed. Data from 177 24‐hour Holter recordings were analyzed to mark the onset and termination of PAF and converted into RR interval files. PAF episodes lasting at least 2 minutes and containing ± 20% noise were included. HR during the first 30‐second segment versus during the remainder of the episode, and the duration of PAF episodes were compared among groups of different ages and sex (Wilcoxon test). Results: 236 episodes from 55 recordings in 32 patients (all patients: 61.4 ± 12.8 years; men (19): 58.5 ± 12.6 years; women (13) 65.5 ± 12.4 years, P = ns for difference in age) fulfilled the inclusion criteria. Women had a higher mean heart rate at AF onset (123 ± 35 beats/min vs 115 ± 20 beats/min, P = 0.02) and during the remainder of the episode (120 ± 25 beats/min vs 112 ± 22 beats/min at the start, P = 0.01, and 116 ± 26 beats/min vs 108 ± 18 beats/min subsequently, P = 0.01). Episodes tended to be longer in women (mean 89.8 min vs 50.5 min, P = NS) and in the aged (mean 83.8 min vs 46.9 min, P = NS). Conclusion: PAF episodes are associated with faster heart rates and last longer in women, which may reflect differing autonomic responses to AF. A slower ventricular rate during PAF in older patients probably reflects an increasing prevalence of impaired atrioventricular conduction.
Effects of a Selective Al‐Adenosine Receptor Agonist on Heart Rate and Heart Rate Variability During Permanent Atrial Fibrillation
Authors: PIOT OLIVIER , CHAUVEL CHRISTOPHE , LAZARUS ARNAUD , PELLERIN DENIS , DAVID DIDIER , LENEVEUT‐LEDOUX LAURENCE , GUIZE LOUIS , LE HEUZEY JEAN‐YVES
Published: July 2006

Background: Mean heart rate and irregularity of the rate, i.e., heart rate variability (HRV), are two aspects of heart rate during atrial fibrillation (AF). An important goal of AF therapy is to control mean heart rate during exercise; the determinants of HRV during AF remain poorly known although its prognostic value has been established. Objectives: To investigate the effects of a stable, long‐acting, selective A1‐adenosine receptor agonist, SDZ WAG994, on heart rate during exercise and on HRV. Methods: In a multicenter, double‐blind, randomized, placebo‐controlled, parallel group study, patients with permanent AF performed a symptom‐limited exercise test and underwent 24‐hour ECG monitoring on day 1 during treatment with placebo, and on day 2 during treatment with either placebo or 2 mg SDZWAG994 orally. Changes in mean heart rate during exercise and changes in HRV indices between day 1 and day 2 were compared between the two groups. Results: Thirty‐two patients (64 ± 8 years; 81% male; 25% in NYHA Class II; 38% with no structural heart disease) were included in the study. During active treatments, heart rate remained unchanged at rest and increased significantly during exercise. A significant daytime increase in short‐term HRV indices (DpNN50 = 4.5% P = 0.01; DrMSSD = 6% P = 0.03; DSDNN Index = 6% P = 0.02) occurred during active treatment. Conclusions: Selective A1‐adenosine receptor agonism with SDZ/WAG994 limits the increase in mean heart rate during exercise in patients with AF. In addition, this agonist selectively increases short‐term HRV indices, suggesting that pNN50, rMSSD, and SDNN reflect vagal influences during AF.
Oral Loading with Propafenone: A Placebo‐Controlled Study in Elderly and Nonelderly Patients with Recent Onset Atrial Fibrillation
Authors: BORIANI GIUSEPPE , BIFFI MAURO , CAPUCCI ALESSANDRO , BOTTO GIAN LUCA , BROFFONI TIZIANA , RUBINO IDA , DELLA CASA STEFANO , SANGUINETTI MARIO , BRANZI ANGELO , MAGNANI BRUNO
Published: July 2006

The efficacy and safety of propafenone as an oral loading dose (600‐mg single oral dose) in converting recent‐onset atrial fibrillation (≤ 7 days duration) to sinus rhythm were evaluated in a single‐blind, placebo‐controlled study according to patients' age. Overall, 240 hospitalized patients, NYHA Class ≤ 2 without signs or symptoms of heart failure were enrolled: among patients aged ≤ 60 years, 55 were allocated to propafenone treatment and 59 to placebo, respectively, and among patients aged > 60 years, 64 were allocated to propafenone treatment and 62 to placebo, respectively. Results: In each age group, the likelihood of conversion to sinus rhythm was significantly greater after propafenone compared with plocebo at 3 and 8 hours. For patients aged ≤ 60 years, corresponding odd ratios were 3.78 (95% CI = 1.80–7.92, P = 0.04) at 3 hours and 4.74 (95% CI = 2.12–10.54, P = 0.02) at 8 hours; for patients aged > 60 years odd ratios were 5.03 (95% CI = 2.08–12.12, P = 0.02) at 3 hours and 6.75 (95% CI = 3.28–73.86, P = 0.01) at 8 hours, respectively. Logistic regression analysis showed that conversion to sinus rhythm within 3 hours was predicted by age ≤ 60 years (P = 0.0064) and by propafenone treatment (P < 0.0001), and conversion to sinus rhythm within 8 hours was predicted by age ≤ 60 years (P = 0.0467) and by propafenone treatment (P < 0.0001). The occurrence of adverse effects was observed in 14%‐16% of propafenone treated patients and in 8% of placebo treated patients without significant differences according to age. In conclusion, in patients with recent‐onset atrial fibrillation without signs of heart failure, propafenone as a single oral loading dose is effective. It is also effective in selected elderly subjects with a favorable safety profile. Moreover, spontaneous conversion to sinus rhythm appears to occur less frequently in elderly patients.
Conversion of Recent‐Onset Atrial Fibrillation to Sinus Rhythm: Effects of Different Drug Protocols
Authors: BORIANI GIUSEPPE , BIFFT MAURO , CAPUCCI ALESSANDRO , BOTTO GIANLUCA , BROFFONI TIZIANA , ONGARI MAURIZIO , TRISOLINO GIUSEPPE , RUBINO IDA , SANGUINETTI MARIO , BRANZI ANGELO , MAGNANI BRUNO
Published: July 2006

In a population of 417 hospitalized patients, the efficacy and safety of different drug regimens administered to convert atrial fibrillation (AF) of recent anset (≤ 7 days duration) to sinus rhythm were evaluated. All patients were in NYHA Class ≤ 2, and free of heart failure. They were randomly allocated to treatment with placebo in 121 patients; IV amiodarone, 5 mg/kg bolus, followed by 1.8 g/24 hours in 51 patients; IV propafenone, 2 mg/kg bolus, followed by 0.0078 mg/kg/min in 57 patients; p.o. propafenone, 600 mg p.o. in a single dose in 119 patients; and p.o. flecainide, 300 mg p.o. in a single dose in 69 patients. All patients were continuously monitored by Holter ECG, and the number of conversions to sinus rhythm was measured at 1, 3, and 8 hours. Results: (1) IV propafenone resulted in a higher conversion rate within 1 hour compared with the oral loading regimens of propafenone or flecainide, but the conversion rates at 3 and 8 hours were comparable, approximately 75% at 8 hours; 2) IV amiodarone was not different from placebo until 8 hours when it was associated with 57% of conversions; (3) conversion to sinus rhythm at 8 hours was observed in 37% of the placebo treated patients. Serious adverse effects occurred in few patients: two patients treated with flecainide and one treated with IV propafenone experienced left ventricular decompensation; one patient treated with placebo and two treated with flecainide had atrial flutter with rapid ventricular response. In conclusion, single‐dose, oral loading with propafenone or flecainide are acceptable alternatives to conventional drug regimens in selected hospitalized patients. In addition, the measure of a placebo effect is mandatory in studies of recent‐onset AF.
Intravenous Propafenone Versus Intravenous Amiodarone in the Management of Atrial Fibrillation of Recent Onset: A Placebo‐Controlled Study
Authors: KOCHIADAKIS GEORGE E. , IGOUMENIDIS NIKOS E. , SIMANTIRAKIS EMMANUEL N. , MARKETOU MARIA E. , PARTHENAKIS FRAGISKOS I. , MEZILIS NIKOS E. , VARDAS PANOS E.
Published: July 2006

The efficacy and safety of intravenous propafenone, amiodarone, or placebo were compared in the treatment of atrial fibrillation (AF) of recent onset (duration ≤ 48 hours). Methods: 143 patients (77 men, mean age 63 ± 12 years) were studied, of whom 46 received propafenone (2 mg/kg over 15 minutes followed by 10 mg/kg over the next 24 hours), 48 received amiodarone (300 mg intravenously over 1 hour, followed by 20 mg/kg over the next 24 hours, plus 1,800 mg/day orally, in 3 divided doses), and 49 received placebo (the equivalent amount of saline IV over 24 hours). Digoxin was administered to all patients who had not previously received it. Results: Conversion to normal sinus rhythm occurred in 36 of 46 patients (78.2%) receiving propafenone, in 40 of 48 patients (83.3%) receiving amiodarone, and in 27 of the 49 (55.10%) controls (P < 0.02, drug vs placebo, between drugs NS). The mean time to conversion was 2 ± 3 hours for propafenone, 7 ± 5 hours for amiodarone, and 13 ± 9 for placebo (P < 0.05). Patients who converted had smaller atria than those who did not (diameter: 42.7 ± 5 vs 47.2 ± 7 mm, P < 0.001 for all). Treatment was discontinued in one patient in the amiodarone group because of an allergic reaction and in two patients in the propafenone group because of excessive QRS widening. No side effects were observed in the placebo group. Conclusions: Both drugs tested intravenously were equally effective and safe for the rapid conversion of recent‐onset atrial fibrillation to sinus rhythm. However, propafenone offered the advantage of more rapid conversion than amiodarone.
Randomized, Crossover, Controlled Comparison of Oral Loading Versus Intravenous Infusion of Propafenone in Recent‐Onset Atrial Fibrillation
Authors: BOTTO GIOVANNI LUCA , BONINI WALTER , BROFFONI TIZIANA , ESPUREO MASSIMO , CAPPELLETTI GIORGIO , LOMBARDI ROSSANA , MOLTENI SANTO , PEDRAGLIO ELENA , FERRARI GIOVANNI
Published: July 2006

A population of 123 patients witb recent‐onset (< 72 hours) atrial fibrillation (AF) without heart failure was randomly treated witb propafenone (PFN) intravenously (IV) (2 mg/kg bolus followed by 0.0078 mg/kg/min infusion) or in a single oral dose (os) (600 mg), or with placebo (PLA) (phase 1). If AF persisted 8 hours later, patients on active drugs received the alternative formulation (crossover), and patients receiving PLA remained on PLA (phase 2). A 24‐hour Holter monitoring was performed and conversion to sinus rhythm (SR) at 1,4, and 8 hours of each phase was used as the criterion of efficacy. Conversion to SR occurred within 1 hour in 48% of patients witb IV‐PFN, 15 % witb os‐PFN, and in 17% with PLA (both P<0.05 vs IV‐PFN). Oral PFN was superior to PLA at 4 hours (71 % vs 33%, P = 0.001) and 8 hours (78% vs 48%, P < 0.01), and 1 at 8 hours also superior to IV‐PFN (53%, P < 0.03). The mean conversion time within 4 hours was shorter with IV‐PFN (25 ± 15′) than with os‐PFN (167 ± 166, P < 0.001) or with PLA (156 ±107′, P < 0.001). The rates of conversion to SR with IV‐PFN after os‐PFN failure were comparable to PLA at any observation time, whereas nonresponders to IV‐PFN who received os‐PFN had significantly higher conversion rates than with placebo at both 4 hours (65% vs 19%) and 8 hours (76% vs 24%; both P < 0.045). Neither serious adverse effects nor episodes of regular tachycardia with 1:1 AV conduction were noted. PFN administered intravenously or in a single oral loading dose was safe and efficacious in converting recent‐onset AF to SR. The rates of conversion were different with different routes of administration: IV‐PFN was superior to os‐PFN over a short observation period, while the overall efficacy of os‐PFN was superior at 8 hours.
Electrophysiological Imaging of the Right Atrium Using a Noncontact Multielectrode Cavitary Probe: Study of Normal and Abnormal Rhythms
Authors: SUN HUABIN , VELIPASAOGLU EMRE O. , BERRIER KEITH L. , KHOURY DIRAR S.
Published: July 2006

Cavitary electmgrams previously were measured from multiple directions simultaneously in the canine left ventricle with the use of noncontact multielectrode probes. The objective of the present study was to measure cavitary electrograms in the canine right atrium (RA) and describe the corresponding global activation sequences during normal and abnormal atrial rhythms. A 64‐electrode custom probe was inserted into the RA of six dogs. Probe position and orientation were guided by fluoroscopy. Probe unipolar electrograms were acquired simultaneously during sinus rhythm, RA pacing, and ventricular pacing, Vagally mediated atrial fibrillation (AF) was induced in four dogs. Probe electrograms were acquired during AF induced at baseline and after intravenous infusion of ibutilide (0.075 mg/kg followed by 0.075 mg/kg infusion over 10 minutes). Isochrone maps were derived from noncontact probe electrograms and were displayed on a beat‐by‐beat basis during normal and paced rhythms. During AF, maps were displayed for 10 consecutive 100‐ms windows. Isochrone maps of normal and paced beats revealed regions of early activation that were consistent with sites of wavefront initiation. During AF, multiple varying activation wavefronts were observed. At baseline, AF cycle length was 110 ± 15 ms and the number of wavefronts was 1.72 ± 0.25 per 100‐ms window. After ibutilide, AF cycle increased to 182 ± 36 ms (P = 0.018) and the number of wavefronts decreased to 0.82 ± 0.14 per 100‐ms window (P = 0.009). In conclusion, global electrophysiological imaging with a noncontact multielectrode probe delineates RA anatomy. Furthermore, images of AF activation depict multiple wandering wavefronts. Ibutilide reduces the number of these wavefronts and organizes AF.
Feasibility and Safety of Two French Electrode Catheters in the Performance of Electrophysiological Studies
Authors: STABILE GIUSEPPE , DE SIMONE ANTONIO , TURCO PIETRO , SENATORS GAETANO , COLTORTI FERNANDO , MARRAZZO NATALE , SOLIMENE FRANCESCO , CHIARIELLO MASSIMO
Published: July 2006

The aim of this study was to analyze prospectively the feasibility and safety of using 2 Fr versus 6 Fr standard electrode catheters for diagnostic electrophysiological study. Methods: Two hundred and five consecutive patients were randomized to receive the 6 Fr approach (3 quadripolar, 6 Fr, electrode catheters inserted through the left or right femoral vein and placed in the high right atrium, right ventricular apex, and His bundle area) or the 2 Fr approach (3 quadripolar, 2 Fr, electrode catheters inserted through a single, 7 Fr, triple lumen, guiding catheter and positioned at the same sites as the 6 Fr approach). Results: Introduction time was shorter in the 2 Fr group (133.3 ± 65 s, range 87–669 s) than in the 6 Fr group (242.8 ± 91.8 s, range 168–1024 s, P < 0.001). The overall fluoroscopy time was longer in the 2 Fr group (141.2 ± 40.1 s, range 78–312 s) than in the 6 Fr group (126.4 ± 39.7 s, range 58–341 s, P = 0.009). However in the last 100 patients there was no more difference between the two groups (137.6 ± 28.2 s vs 128.4 ± 23.2 s, P = 0.07). There was no significant difference between 2 Fr and 6 Fr groups in the mean atrial (5.9 ± 2.2 mV, range 2.2–11.3 mV, vs 6.1 ± 2.3 mV, range 2.4–12.4 mV, P =0.57) and ventricular (5.6 ± 2.1 mV, range 1.9–9.7 mV, vs 5.7 ± 2.2 mV, range 2.3–10.5 mV, P = 0.66) activation potential amplitudes recorded during sinus rhythm, or in the rate of stable His bundle potential recording (P = 0.3), and catheter dislodgment (P = 0.54). The overall number of complications was significantly higher in the 6 Fr group than in the 2 Fr group (29 vs 5, P = 0.001), as well as the number of entry site related complications (3 vs 12, P = 0.02) and catheter manipulation related complications (2 vs 17, P < 0.001). Conclusions: The results of this study show that the use of 2 Fr electrode catheters reduces the rates of entry site and catheter manipulation related complications during EPS. Despite their small size, these catheters allow quick and precise positioning of the electrode.
Electrophysiological Characteristics During Slow Pathway Ablation of Posterior Atrio ventricular Junctional Reentrant Tachycardia
Authors: FUJII EITARO , KASAI ATSUNOBU , OMICHI CHIKAYA , TERAMURA SHINOBU , YASUDA MASAKI , UCHIDA FUMIYA , NAKANO TAKESHI
Published: July 2006

The purpose of this study was to compare the electrophysiological characteristics of posterior and anterior atrioventricular junctional reentrant tachycardia (AVJRT) during radiofrequency (RF) catheter ablation of a slow pathway. Twenty‐four patients with common A VJRT, including 4 posterior (P) and 20 anterior AVJRT (A) were studied. We analyzed the retrograde atrial activation sequence of junctional rhythm and the presence of transient HA block during slow pathway ablation. When HA block developed, the AH interval before ablation and immediately after the end of energy delivery was measured. Successful ablation sites were divided into three groups; high (H), middle (M), and low (L) from the His bundle to the floor of the coronary sinus orifice. The results were: (1) the number of successful ablation sites were H 0, M 1, L 3 in P and H 1, M 8, L 11 in A; (2) the HA interval during AVJRT in P was longer than that in A (109 ± 48 ms vs 43 ± 6 ms, P < 0.01); (3) the retrograde atrial activation sequence during Junctional rhythm was strictly concordant with that during AVJRT in both groups, but HA block developed during slow pathway ablation more often in P than in A (100% vs 30%, P < 0.01); and (4) The AH interval did not lengthen after HA block developed in P. These data suggest that another pathway does exist from the A V node to the atrium in addition to anterograde fast pathway and slow pathway, and that this pathway is used as the retrograde limb of P.
Activation Mapping from the Coronary Sinus May Be Limited by Anatomic Variations
Authors: YAMANOUCHI YUMI , IGAWA OSAMU , HISATOME ICHIRO
Published: July 2006

The purpose of this study was to examine the anatomic relationship between the mitral annulus (MA) and the coronary sinus (CS). Fifty consecutive hearts of 31 men and 19 women, 63.5 ± 13.7 years of age, were examined at autopsy. MA was divided perpendicularly to the annular plane into an anteromedial block and a posterolateral block by sectioning from the CS ostium through the center of MA. The posterolateral block was subdivided radially into five equal sections at 36°, 72°, 108°, 144°, and 180°. The distance from the ventricular endocardium under MA to the nearest wall of CS (D) was measured in each cross‐section. D measured 9.7 ± 2.3, 10.9 ± 3.3, 10.2 ± 3.6, 9.2 ± 3.4, and 8.2 ± 2.9 mm at 36°, 72°, 108°, 144°, and 180°, respectively. D at 72 was significantly longer than at 144° and 180° (P < 0.01). Likewise, D at 108° was significantly longer than at 144° and 180° (P < 0.05). The population was divided according to the morphology into five patterns. “Type C” the pattern that separated in the middle section and then reapproximated, was more common (66%) than any other pattern. D was confirmed to be longest at the level of the 72° section, corresponding to a left posterolateral free‐wall location. The potential mapping in CS would be easily modified by this anatomic feature. When mapping activation from the CS, the electrophysiohgical data should be interpreted in light of these anatomic findings.
Two‐staged Biatrial Linear and Focal Ablation to Restore Sinus Rhythm in Patients with Refractory Chronic Atrial Fibrillation: Procedure Experience and Follow‐up Beyond 1 Year
Authors: MALONEY JAMES D. , MILNER LADYNE , BAROLD SERGE , CZERSKA BARBARA , MARKEL MICHAEL
Published: July 2006

Recent observations regarding the mechanisms of chronic atrial fibrillation (CAF) plus a few encouraging clinical reports have created a paradigm shift regarding treatment strategies and the potential for restoring normal sinus rhythm (NSR) utilizing available catheter‐based ablation techniques. The initial and late follow‐up clinical experience with a two‐staged biatrial linear and focal radiofrequency ablation (BALF I, II) procedure to restore NSR in patients with CAF are described. Pre‐BALF management included confirming drug refractoriness and optimizing anticoagulation therapy. BALF I and II were preceded by trans‐esophageal echocardiography to exclude thrombus. Femoral venous catheters were placed in the left atrium and the right atrium with extensive left atrial mapping, ablation (linear and focal) and more limited right atrial ablation. Localized electrogram recordings demonstrated rapid, localized, stable focal driving rotors (FDRs) in the left atrium (nine patients) and in the right atrium (one patient). Atrial or intraatrial tachycardia (IAT) commonly recurred after BALF I. BALF II addresses these recurrences by repeat mapping and ablation techniques. There were no thromboembolic complications. Two patients developed pericardial tamponade that responded to medical management. Of the 11 patients with late follow‐up data, 9 have NSR, atrial function, and are no longer experiencing CAF. Left atrial ablation lines decrease continuous electrogram activity, probably isolate portions of the atrium, and unmask FDRs. Focal and linear ablations appear helpful in transforming CAF to NSR. FDRs are commonly localized to pulmonary vein ostium, trabeculated portions of the atrium, and left atrial appendage.
Long‐Term Follow‐Up After Right Atrial Radiofrequency Catheter Treatment of Paroxysmal Atrial Fibrillation
Authors: JAÏS PIERRE , SHAH DIPEN C. , TAKAHASHI ATSUSHI , HOCINI MÉLÈZE , HAÏSSAGUERRE MICHEL , CLÉMENTY JACQUES
Published: July 2006

Catheter ablation of paroxysmal atrial fibrillation using long linear lesions in the right atrium is still under investigation, and its long‐term follow‐up is unknown. Methods: Thirty‐six men and nine women (aged 51 ± 12 years) with symptomatic daily episodes of AF for 6 ± 5 years despite the use of 4.7 ± 1.5 antiarrhythmic drugs were studied between July 1994 and January 1996. Progressively longer ablation lines were performed in 3 groups of 15 consecutive patients each, using a 14‐electrode catheter or a single‐electrode dragging technique. Success was defined as atrial fibrillation elimination or recurrence for no longer than 6 hours over 3 months of observation. Patients who had fewer than 6 hours of atrial fibrillation per month were considered “improved.” Medium‐ (11 ± 4 months) and long‐term (26 ± 5 months) results were assessed clinically from a patient's diary and from Holter recordings. Results: After a follow‐up of 11 months, 24 patients had a favorable result of the ablation procedure with or without additional antiarrhythmic drug therapy, representing 53% of the original cohort. After 26 ± 5 months of follow‐up, these successful results were reduced to 17 patients (37%). Conclusions: After linear atrial ablation, a significant long‐term attrition of arrhythmia‐free patients was observed. This may be due to a combination of disease progression, incomplete linear block, and ineffective ablation of arrhythmogenic triggers.
Segment by Segment Linear Ablation with an Articulated Bilimb Catheter: Initial Experimental Results
Authors: LAVERGNE T. , JAÏS PIERRE , BRUSZEWSKI W. , SHAH DIPEN C. , BRUNEVAL P. , TAKAHASHI A. , GUIZE L. , CLÉMENTY JACQUES , GAISER J. , HAÏSSAGUERRE MICHEL
Published: July 2006

Transcatheter radiofrequency (RF) ablation of atrial fibrillation or flutter requires the creation of linear lesions. However, conventional catheters are not predictably effective because of poor endocardial contact, and limited lesion size and penetration. The purpose of the study was to assess, in the right atrium, the efficacy and safety of a new catheter designed to create long myocardial tissue lesions using RF energy. The main characteristics of this 8 Fr deflectable RF ablation catheter were: (1) a perpendicularly contacting articulated bilimb electrodes ensuring stable and firm endocardial firm contact; and (2) an irrigated planar interface. Three different electrode prototypes were tested. Fourteen anesthetized sheep weighing 61 ± 7 kg underwent RF ablation in the right atrium using three incremental power levels (25 to 45, 50, 55 to 75 W) with the aim of creating fully transmural (FT) lesions, defined as continuous and complete epicardial and endocardial lesion imprints. The animals were euthanized 1 hour later for macroscopic and histologic examinations. Forty‐three of the 80 right atrial lesions created, in smooth as well as in trabeculated areas, were FT. The percentage of FT lesions increased with the applied power from 37% with 25–45 W, to 49% with 50 W, and up to 86% for 55–75 W. In all but two cases, histologic examination showed no discontinuity between FT lesions produced by both limbs resulting in 19 coalescent linear lesions with an average size of 25 × 6 × 4 mm (length × width × depth). In situ bipolar electrograms after ablation in the FT group showed split potentials and/or a marked decrease in amplitude from 2.85 ± 1.79 to 0.33 ± 0.14 mV (P = 0.001) accompanied by near complete disappearance of unipolar electrograms. There was no perforation due to RF ablation. In conclusion, continuous and FT lesions can be achieved in various areas of sheep atria, including the trabecular right atrium, with a perpendicularly contacting bilimb electrode catheter. It represents a promising tool for catheter ablation of atrial fibrillation and flutter.
Radiofrequency Catheter Ablation of Symptomatic Ventricular Ectopic Beats Originating in the Right Outflow Tract
Authors: LAUCK GERHARD , BURKHARDT DIETMAR , MANZ MATTHIAS
Published: July 2006

Ectopic activity originating in the right ventricular outflow tract is a frequent finding and may result in severe symptoms such as dyspnea, palpitations, and lack of physical capacity correlated with a low cardiac output. In 12 consecutive symptomatic and drug refractory patients, we performed a study with intracardiac mapping and ablation procedure. The origin of the ectopic beats was identified, and the ablation procedure was performed. Patients were examined by serial ECG, Holter ECG, bicycle ECG, echocardiography, and thoracic X ray. At baseline, the mean number of ectopic beats was 23,823 during Holter ECG. No other arrhythmias were present. Patients underwent basic electrophysiological study, mapping process, and ablation in a single procedure. Ablation was performed with a deflectable thermocoupled catheter with tip electrodes of 4 mm. Criteria for identification of the origin of the ectopic beats included pace mapping with 12 leads and earliest endocardial activation. One male patient suffered from myocarditis; the other 11 patients had no underlying structural heart disease. The mean age was 38 years. Ablation procedure with delivered temperature of 70 °C was successful in 11 of 12 patients eliminating the focus. The mean procedural time was 79± 34 minutes; mean fluoroscopy time was 13.8± 8.8 minutes; and mean number of applications was 4.4± 2.8. No adverse effects occurred during a follow‐up period of 10 months after ablation. The mean number of ectopic beats per 24 hours after ablation was 317 ± 599 with a P value of 0.00024. The clinical symptoms improved in all but one patient. One patient had a recurrence after 2 months that could be successfully treated by a second procedure. In our experience, temperature guided radiofrequency catheter ablation is safe and effective for the treatment of patients with symptomatic ectopic activity of the right outflow tract. As long as we lack the experience of a greater patient cohort and a longer follow‐up, only drug resistant and highly symptomatic patients should be selected.
Atrial Ejection Force in Patients with Atrial Fibrillation: Comparison Between DC Shock and Pharmacological Cardioversion
Authors: MATTIOLI ANNA VITTORIA , CASTELLI ANNADELE , BASTIA ELISABETTA , MATTIOLI GIORGIO
Published: July 2006

It is well known that the restoration of sinus rhythm is not always associated with the return of effective atrial contraction. Atrial ejection force (AEF) is a noninvasive Doppler derived parameter that measures the strength of the atrial contraction. The aim of the present study was to use pulsed‐Doppler echocardiography to determine if different modalities of cardioversion influence the delay in the return of effective atrial contraction after cardioversion. DC shock and pharmacological therapy were compared. Sixty‐eight patients were randomly cardioverted, either using DC shock or i.v. procainamide. The patients who were restored to a sinus rhythm had a complete Doppler echocardiographic examination within 1 hour after the restoration, after 24 hours, after 1 month, and after 3 months. AEF was measured and compared in the two groups of patients and within the same group. AEF was greater immediately and at 24 hours after cardioversion in patients who underwent pharmacological therapy compared to patients treated with DC shock (peak A wave, 60 ± 9 vs 31 ± 8 msec, P < 0.001; AEF 11.3 ± 3 vs 5 ± 2.9 dynes, P < 0.001). In both groups, AEF increases over time. In conclusion, AEF is a noninvasive parameter that can be easily measured after cardioversion and can give accurate information about the recovery of left atrial mechanical function. This finding may have important implications for guiding the anticoagulant therapy after cardioversion.
Reversing the Initial Phase Polarity in Biphasic Shocks: Is the Polarity Benefit Reproducible?
Authors: NARASIMHAN CALAMBUR , PANOTOPOULOS PANAGIOTIS TH. , DESHPANDE SANJAY , JAZAYERI MOHAMMAD R. , DHALA ANWER , BLANCK ZALMEN , AKHTAR MASOOD , SRA JASBIR
Published: July 2006

The effect of initial phase polarity (IPP) reversal using biphasic shocks on DFT at the time of implantation of implantable cardioverter defibrillator and the reproducibility of this effect during predischarge testing was evaluated in a randomized fashion. Twenty‐two patients with ventricular tachycardia or ventricular fibrillation (VF) who received either the Medtronic 7219D (7 patients), 7219C (12 patients), 7223 (1 patient), or CPI Ventak MINI (2 patients) were studied. The DFT was determined in a randomized fashion at implantation and during predischarge testing using a binary search protocol. Initial shock was delivered at 12 J. If successful, subsequent shock was delivered at 6 J, following which the shock was incremented or decremented by 3 J depending upon the success. The DFT for right ventricular (RV)‐and RV + IPP was 10.9 ± 4.1 J and 11.1 ± 4.0 J, respectively, at implant (P = ns) and 9.7 ± 4.3 J and 8.4 ± 6 J, respectively, (P = ns) at predischarge testing. Of the six patients who had better DFT with RV+ at implantation, only one patient maintained the benefit during predischarge testing. The differences observed in IPP in individual patients may not be demonstrable during repeated testing. These findings may have implications on how these devices should be programmed.
A Nodoventricular Fiber Associated with Dual AV Nodal Conduction, AV Nodal Reentrant Tachycardia, and Anterior Location of the Slow AV Nodal Pathway
Authors: EVANS STEVEN J.L. , BLUMBERG STEPHEN M. , SCHEINMAN MELVIN M.
Published: July 2006

We present a case of a patient with a nodoventricular tract, associated with dual AV nodal conduction and AV nodal reentrant tachycardia, and an anteroseptal location of the slow AV nodal pathway. The remarkable feature of this case is the site of successful ablation, in the anteroseptum just anterior and superior to the His bundle, where both preexcitation and dual AV nodal physiology were abolished.
Radiofrequency Catheter Ablation of Ventricular Tachycardia Guided by Nonsurgical Epicardial Mapping in Chronic Chagasic Heart Disease
Authors: SOSA EDUARDO , SCANAVACCA MAURICIO , D'AVILA ANDRÉ , BELLOTTI GIOVANNI , PILLEGGI FULVIO
Published: July 2006

We report a case of a 63‐year‐old women with Chagas'disease and recurrent, syncopal VT treated by RF catheter ablation in whom endocardial application of RF energy was guided by nonsurgical epicardial mapping. The procedure was undertaken in the electrophysiology laboratory under deep anesthesia. VT was interrupted after 2.4 seconds of application and rendered noninducible afterwards. Two weeks after the procedure, a distinct morphology VT was induced by programmed ventricular stimulation, and the patient was started on amiodarone, remaining asymptomatic 12 months after the procedure.
BOOK REVIEW
Authors: Dorostkar Parvin
Published: July 2006

Book reviewed in this article:

Current Concepts in Diagnosis and Management of Arrhythmias in Infants and Children.
Edited by Barbara J. Deal, Grace S. Wolff, and Henry Gelband
The Influence of Specific and Nonspecific Potassium Current Blockade on the Defibrillation Energy Requirement of Biphasic Shock
Authors: MEHDIRAD ALI A. , CARNES CYNTHIA A. , NELSON STEVEN D.
Published: July 2006

Block of delayed rectifier potassium current (IK) is known to decrease defibrillation energy requirements (DERs). We tested the hypothesis that there would be no difference in DER reduction with a nonspecific IK (IKr+ IKS) blocker, ambasilide, and a specific IKr blocker, dofetilide. Methods: An anesthetized canine model (n = 30) of internal transvenous defibrillation with biphasic shocks was used. Ambasilide (n = 9; dose: 4.8 mg/kg, then 9.6 mg/kg/hour), dofetilide (n = 10; dose: 10 (μg/kg, then 3.6 (μg/kg/hour), or matched placebo (n = 11) were administered. DERs (J) were determined in triplicate using an increment‐decrement protocol at baseline and during each treatment. ECG intervals were measured at baseline and during each treatment. ANOVA with post‐hoc Bonferroni test was used for statistical analysis. Results: Ambasilide resulted in a +23.5 ± 4.06% prolongation of the QTc interval, while dofetilide resulted in a +20.5%± 3.76% prolongation of the QTc interval. Thus, the two drugs resulted in comparable prolongation of the QTc interval (P < 0.05 compared to placebo). Both drugs significantly reduced the DER (‐17.7%± 5.33% reduction by ambasilide, and ‐21.9%± 5.21% reduction by dofetilide, P < 0.05 compared to placebo). There was no difference in the magnitude of DER reduction between the two treatments. Conclusions: Administration of equipotent doses (as indicated by QTc changes) of ambasilide or dofetilide had comparable effects on DERs. Selectivity of IK blockade has no significant effect on the magnitude of reduction in DERs.
Clinical Evaluation of a Prototype Passive Fixation Dual Chamber Single Pass Lead For Dual Chamber ICD Systems
Authors: BUTTER CHRISTIAN , AURICCHIO ANGELO , SCHWARZ TORSTEN , FLECK ECKART , SCHUBERT BERND , HSU WILLIAM , MICHEL ULRICH , NEUZNER JÖRG
Published: July 2006

Dual chamber ICD systems use two separate leads for sensing. We developed and tested a new prototype of a single pass dual chamber passive fixation lead for dual chamber ICDs. Methods and Results: The prototype was a modification of the Guidant CPI Endotak DSP lead. The additional sensing electrode for the right atrium consisted of a side‐mounted porous atrial ring electrode (AR). Atrial signals were recorded from the lead in patients during normal sinus rhythm (NSR), atrial fibrillation (AFib), and/or atrial flutter (AFl) with the AR in stable contact with the atrial wall or floating. During NSR, with the AR in contact with the atrial wall, an average P wave amplitude of 7.2 ± 1.5 mV (mean ± SD, n = 12) was measured. After induction of AFib/AFl, the single amplitude decreased to 3.6 ± 1.5 mV (n = 8) during AFib and 3.4 ± 1.7 mV (n = 9) during AFl. Amplitudes dropped between 53% and 75% when the AR lost atrial wall contact. The atrial pacing threshold was 1.0 ± 0.4 V (n = 16) when the AR was in contact with the atrial wall. Conclusions: In future dual chamber ICDs the signals from a passive fixation single pass lead could be used for atrial sensing and pacing as long as the sensing electrode for the right atrium remains in contact with the atrial wall. This system might lead to a simpler, less invasive implantation of dual chamber ICD systems.
Reliability of Coated Wire Defibrillation Leads
Authors: TYERS G. FRANK O. , SANDERS RICHARD , WILLIAM JACQMEIN B.S.
Published: July 2006

A higher rate of complications and need for reoperation has been identified with epicardial and endocardial defibrillator systems. Improved reliability may be achieved with alternate designs that use coated wire and coated coil conductors. Six‐year reliability in the 98% range is reported for one bipolar design, the Sulzer Intermedics Intervene® lead.
A New Defibrillator Discrimination Algorithm Utilizing Electrogram Morphology Analysis
Authors: GOLD MICHAEL R. , HSU WILLIAM , MARCOVECCHIO ALAN F. , OLSOVSKY MARY R. , LANG DOUGLAS J. , SHOROFSKY STEPHEN R.
Published: July 2006

Inappropriate therapies delivered by implantable cardioverter defibrillators (ICDs) for supraventricular arrhythmias remain a common problem, particularly in the event of rapidly conducted atrial fibrillation or marked sinus tachycardia. The ability to differentiate between ventricular tachycardia and supraventricular arrhythmias is the major goal of discrimination algorithms. Therefore, we developed a new algorithm, SimDis, utilizing morphological features of the shocking electrograms. This algorithm was developed from electrogram data obtained from 36 patients undergoing ICD implantation. An independent test set was evaluated in 25 patients. Recordings were made in sinus rhythm, sinus tachycardia, and following the induction of ventricular tachycardia and atrial fibrillation. The arrhythmia complex is defined as wide if the duration is at least 30% greater than the template in sinus rhythm. For narrow complexes, four maximum and minimum values were measured to form a 4‐element feature vector, which was compared with a representative feature vector during normal sinus rhythm. For each rhythm, any wide complex was classified as ventricular tachycardia. For narrow complexes, the second step of the algorithm compared the electrogram with the template, computing similarity and dissimilarity values. These values were then mapped to determine if they fell within a previously established discrimination boundary. On the independent test set, the SimDis algorithm correctly classified 100% of ventricular tachycardias (27/27), 98% of sinus tachycardias (54/55), and 100% of episodes of atrial fibrillation (37/37). We conclude that the SimDis algorithm yields high sensitivity (100%) and specificity (99%) for arrhythmia discrimination, using the computational capabilities of an ICD system.
A Fuzzy Logic‐Controlled Classifier for Use in Implantable Cardioverter Defibrillators
Authors: USHER JODIE , CAMPBELL DUNCAN , VOHRA JITU , CAMERON JIM
Published: July 2006

Purpose: Implantable cardioverters defibrillators (ICDs) are increasingly used in the management of life‐threatening arrhythmias. Correct recognition of a treatable arrhythmia is crucial to this application. However, the computational power of microprocessors currently used in ICDs limits the range of traditional algorithms available for this application. Methods: Classification based on fuzzy inference systems (FIS) were trained to recognize different cardiac rhythms (AF, VF, SVT, VT) from the Ann Arbor Electrogram Library. The FIS used were designed using adaptive‐network‐based fuzzy inference methods to optimize the classification procedure. Only computational techniques suitable for ICD design were used. Results: After pretraining with the ANFIS correct rhythm classification was observed for the rhythms studied. Conclusion: In this preliminary study, successful rhythm classification was demonstrated using fuzzy logic techniques. In view of the computational efficiency this may have application in ICD design.
Prehospital Discharge Defibrillation Testing in ICD Recipients: A Prospective Study Based on Cost Analysis
Authors: LURIE KEITH G. , ISKOS DEMOSTHENES , FETTER JOSEPH , PETERSON COLLEEN A. , COLLINS JOANNE M. , SHULTZ JEFFERY J. , FAHY GERARD J. , SAKAGUCHI SCOTT , BENDITT DAVID G.
Published: July 2006

Prehospital discharge defibrillation testing is often performed to verify the function of newly implanted cardioverter defibrillators (ICDs). To determine whether elimination of predischarge testing could reduce costs without placing patients at additional risk, 31 patients were randomized in this prospective clinical evaluation to either receive or not receive a predischarge ICD defibrillation test. Expenses associated with postimplant care was the primary endpoint. All patients underwent induction of ventricular fibrillation after 6 months to evaluate ICD function. The groups were well matched in terms of patient characteristics, initial lead implant parameters, and defibrillation thresholds. Elimination of prehospital discharge testing resulted in a savings of $1,800/patient after 6 months, with no difference between groups in terms of ICD complication rates or unanticipated hospital admissions. Further studies are needed to better define the most appropriate time to assess defibrillation thresholds in the first year after implantation.
Late Retesting of System Performance in ICD Patients Without Spontaneous Shocks
Authors: ZILO PHILIP , WEISS DANIEL N. , LUCERI RICHARD M.
Published: July 2006

One hundred five implantable cardioverter defibrillator (ICD) patients (71 ± 9 years of age, 83% men) without spontaneous ICD discharges for ≥ 12 months were tested to assess high voltage (HV) circuit integrity and the system's ability to recognize and terminate ventricular fibrillation (VF). Indications for ICD implantation were sustained ventricular tachycardia (VT) (35%), cardiac arrest (27%), and inducible VT (38%). Eighty‐two percent of the patients had coronary artery disease (CAD), and the mean left ventricular ejection fraction (LVEF) was 36%± 13%. Results: One hundred patients had inducible VF and five did not. Testing led to ICD reprogramming in 50 (49%) patients. Two (1.9%) patients required ICD replacement: (1) a 45‐year‐old patient with a Ventritex 110 ICD implanted for 13 months interfaced with a CPI 0062 lead implanted for 46 months could not be defibrillated internally (impedance nonmeasurable); (2) an 82‐year‐old patient with a 23‐month‐old Medtronic 7219 ICD interfaced with 6936 and 6933 leads whose defibrillation threshold (DFT) had doubled since implantation (24 J from 12 J). Lead fractures were found in both cases (proximal coil of the 0062, and subcutaneously in the 6933). Based on DFT determinations, the first shock output was programmed lower in 37 patients and higher in 10 patients. Shock pulse width was changed in one patient and the ventricular refractory period in another. No programming changes were made in 54 (51%) patients. Conclusions: (1) Late testing of HV circuit integrity in ICD patients without an ICD shock in ≥ 12 months identifies previously unsuspected HV lead fractures; (2) chronic DFT testing resulted in HV output reprogramming in one‐half of the patients.