bluuebunny/crossref_metadata_2025_split huggingface dataset:
Catheter Ablation of Ventricular Tachycardia in Remote Myocardial Infarction:
Authors: Kottkamp Hans , Wetzel Ulrike , Schirdewahn Petra , Dorszewski Anja , Gerds‐li Jin‐Hong , Carbucicchio Corrado , Kobza Richard , Hindricks Gerhard 
Published: August 2010

Introduction: The aim of this study was to describe the arrhythmogenic substrate in postinfarction patients with ventricular tachycardia (VT) guiding the placement of individual strategic linear lesions transecting all potential isthmuses using target area maps with limited mapping points to allow short procedure times. Methods and Results: In 28 patients with pleomorphic, unstable, and/or incessant VT, electroanatomic voltage mapping was performed in conjunction with limited sinus rhythm mapping, pace mapping, and activation mapping. Radiofrequency (RF) energy was applied directly within the low‐voltage areas of the chronically infarcted areas or in the border zone. Ablation lines typically were perpendicular to the course of the presumed central common pathways. The maps consisted of 63 ± 30 mapping points. An average lesion line length of 46 ± 21 mm was placed with 17 ± 7 RF pulses. Twenty‐two (79%) of the 28 patients were rendered completely noninducible at the end of the procedure. Procedure time measured 134 ± 41 minutes. No major complications were observed. Six (27%) of 22 patients who were rendered completely noninducible experienced VT recurrence during follow‐up versus 4 (67%) of 6 patients who were still inducible after ablation (P = 0.06). Conclusion: Individually tailored substrate description guiding the placement of linear lesion lines transecting potential isthmuses rendered 80% of the patients completely noninducible. The construction of regional target area maps allowed short procedure times, with a resulting low incidence of complications in these critically ill patients. (J Cardiovasc Electrophysiol, Vol. 14, pp. 675‐681, July 2003)
Prevention of Paroxysmal Atrial Fibrillation in Patients with Sinus Bradycardia:
Authors: Padeletti Luigi , Botto Gianluca , Spampinato Andrea , Michelucci Antonio , Colella Andrea , Porciani Maria Cristina , Pieragnoli Paolo , Ciapetti Cristina , Musilli Nicola , Sagone Antonio , Martelli Moira , Raneri Rossana , Grammatico Andrea 
Published: August 2010

Introduction: Right atrial linear lesions (RALL), either alone or in combination with antiarrhythmic drug therapy, may modify the substrate for maintenance of atrial fibrillation (AF). The aim of this prospective randomized study was to determine whether RALL provides additional benefit to right atrial appendage pacing (RAAP) and/or interatrial septum pacing (IASP) and drug therapy in patients with symptomatic paroxysmal AF and sinus bradycardia requiring permanent atrial pacing. Methods and Results: Sixty‐four patients (33 men and 31 women, mean age 73 ± 10 years) completed the 6‐month follow‐up. Patients were randomized to either RALL (n = 33) or non‐right atrial linear lesions (NRALL), and then to either IASP (n = 32) or RAAP (n = 32). Fifteen RALL patients were paced at the IAS and 18 at the RAA. Seventeen NRALL patients were paced at the IAS and 14 at the RAA. No statistical difference was observed with regard to the mean atrial tachyarrhythmia (AT) burden between NRALL (84 ± 169 min/day) and RALL patients (202 ± 219 min/day). Mean AT burden was significantly lower in the IASP group (70 ± 150 min/day) than in RAAP group (219 ± 317 min/day; P < 0.016). In the RALL group, the mean AT burden was 99 ± 180 min/day in the IASP patients and 288 ± 372 min/day in the RAAP patients (P < 0.046). In the NRALL group, no statistical difference in the mean AT burden was observed between IASP patients (46 ± 117 min/day) and RAAP patients (130 ± 211 min/day). Conclusion: The results of the present study indicate that RALL did not provide any additional therapeutic benefit to combined antiarrhythmic drug therapy and septal or nonseptal atrial pacing in patients with sinus bradycardia and paroxysmal AF. (J Cardiovasc Electrophysiol, Vol. 14, pp. 733‐738, July 2003)
Discrimination of Left Atrial and Pulmonary Vein Potentials in Patients with Paroxysmal Atrial Fibrillation
Authors: Patel Nirav , Kay G. Neal , Sanchez Javier , Ideker Raymond E. , Smith William M. 
Published: August 2010

Introduction: Ablation of muscular fascicles around the ostium of pulmonary veins (PVs) resulting in electrical isolation of the veins may prove to be an effective treatment for atrial fibrillation (AF). Correctly discriminating atrial and PV potentials is necessary to effectively isolate PVs from the left atrium in patients with paroxysmal AF. Methods and Results: A training set of 151 electrode recordings obtained from 10 patients with AF was used to develop an algorithm to discriminate atrial and PV potentials. Bipolar electrograms were collected from a multielectrode basket catheter placed sequentially into each PV. Amplitude, slope, and normalized slopes of both bipolar and quadripolar electrograms (difference between adjacent bipoles) were entered into a binary logistic regression model. A receiver operating characteristic curve was used to define a threshold able to effectively discriminate atrial and PV potentials. The normalized slopes of both domains, bipolar and quadripolar, produced a logistic function that discriminated atrial and PV potentials against a threshold (0.38) with 97.8% sensitivity and 94.9% specificity. The algorithm then was evaluated on a test set of 214 electrode recordings from four patients who also had paroxysmal AF. These patient electrograms also were evaluated by two independent electrophysiologists. The algorithm and electrophysiologists matched identification of activation origin in 84% of electrograms.Conclusion: Atrial and PV potentials acquired from a multielectrode basket catheter can be discriminated using the normalized slopes of bipolar and quadripolar electrograms. These additional parameters need to be included by physicians determining the preferential ablation site within PVs. (J Cardiovasc Electrophysiol, Vol. 14, pp. 698‐704, July 2003)
Heart Rate Dependence of the QT Interval Duration:
Authors: NĚMEC JAN , BUNCOVÁ MARIE , BŮLKOVÁ VERONIKA , HEJLIK JOSEPH , WINTER BRUCE , SHEN WIN‐KUANG , ACKERMAN MICHAEL J. 
Published: August 2010

Introduction: The heart rate dependence of QT interval duration is abnormal in patients with congenital long QT syndrome. Patients with LQT1 have a defective IKs current, a major determinant of QT response to heart rate. Methods and Results: We studied the heart rate dependence of QT interval duration in different long QT syndrome genotypes and control subjects using computerized QT measurements obtained from Holter recordings. The dependence of QT duration on heart rate is steeper in long QT syndrome than in control subjects (0.347 ± 0.263 vs 0.162 ± 0.083 at heart rate 100 beats/min; P < 0.05). In addition, QT interval is significantly longer in LQT2 and LQT3 than in LQT1 patients at slow (533 ± 23 ms vs 468 ± 30 ms at heart rate 60 beats/min; P < 0.0001) but not at rapid heart rate. The heart rate dependence of QT interval is steeper in LQT2 and LQT3 than in LQT1 (0.623 ± 0.245 vs 0.19 ± 0.079 at heart rate 100 beats/min; P < 0.05). For a given heart rate, the QT intervals vary more in LQT2 and LQT3 than in LQT1 patients (25.98 ± 11.18 ms vs 14.39 ± 1.55 ms; P < 0.01). Conclusion: Individual long QT syndrome genotypes differ with respect to QT interval dependence on heart rate. These differences may relate to the propensity of LQT2 and LQT3 patients to develop arrhythmias during bradycardia. (J Cardiovasc Electrophysiol, Vol. 15, pp. 550‐556, May 2004)
Electrophysiologic Effects of Salbutamol, a β2‐Selective Agonist
Authors: INSULANDER PER , JUHLIN‐DANNFELT ANDERS , FREYSCHUSS ULLA , VALLIN HANS 
Published: August 2010

Introduction: A positive chronotropic effect of β2 stimulation is well known. Case reports of ventricular arrhythmias during β2‐inhalation therapy have been published. The aim of this study was to asses the overall electrophysiologic effects of the β2‐agonist salbutamol. Methods and Results: Electrophysiologic and hemodynamic variables were measured in 10 healthy volunteers during atrial pacing at baseline and during infusion of salbutamol at two different rates (0.1 and 0.2 μg/kg/min). To characterize β2‐agonist effects, a comparison was made with the β1‐selective agonist dobutamine. Salbutamol infusion produced significant changes in electrophysiologic properties in both myocardial and nodal tissues, with significantly greater effects on nodal properties. The proportional decreases in AV nodal parameters were more pronounced than in the sinus node (P < 0.001). An interesting result was a significant increase in the duration of the QS interval, which in the presence of an unchanged His‐Purkinje conduction (HV) represents slower depolarization of the ventricle. QT dispersion also increased. Conclusion: Infusion of salbutamol results in significant electrophysiologic effects on most heart structures, proportionally most pronounced in the AV node. Discordant effects on ventricular conduction, which slowed, and the refractoriness of the ventricular myocardium, which shortened, were seen. QT dispersion was increased. (J Cardiovasc Electrophysiol, Vol. 15, pp. 316‐322, March 2004)
Common Left Pulmonary Vein:
Authors: SCHWARTZMAN DAVID , BAZAZ RAVEEN , NOSBISCH JOHN 
Published: August 2010

Introduction: The discovery of a consistent relationship between atrial anatomy and electrophysiology would have practical value and may provide insight into arrhythmia mechanism. We previously observed that anatomically common left pulmonary veins were a disproportionate source of atrial ectopy that was associated with the initiation of atrial fibrillation (“arrhythmogenic”). This report details our efforts to characterize and quantify this observation. Methods and Results: One hundred subjects with paroxysmal atrial fibrillation underwent computed tomographic scanning to characterize left atrial anatomy and invasive electrophysiology study to characterize events associated with the initiation of atrial fibrillation. Some of these subjects also underwent radiofrequency catheter ablation. The left pulmonary vein was common in 14 subjects and was a consistent source of arrhythmogenic ectopy. This relationship was significantly stronger than for any other individual vein or ipsilateral vein combination. Myocardium located within the common vein trunk was the site of origin of the ectopy in most subjects. This myocardium did not have unique electrophysiologic properties. Catheter ablation to isolate myocardium proximal to junction between the common vein and the left atrial body cured all patients in whom the vein was the sole source of arrhythmogenic ectopy. Conclusion: In this cohort, a common left pulmonary vein was a consistent source of arrhythmogenic atrial ectopy. (J Cardiovasc Electrophysiol, Vol. 15, pp. 560‐566, May 2004)
Improvement of Defibrillation Efficacy with Preshock Synchronized Pacing
Authors: PAK HUI‐NAM , OKUYAMA YUJI , OH YONG‐SEOG , HAYASHI HIDEKI , LIU YEN‐BIN , CHEN PENG‐SHENG , LIN SHIEN‐FONG 
Published: August 2010

Introduction: We previously demonstrated that wavefront synchronization by spatiotemporal excitable gap pacing (Sync P) is effective at facilitating spontaneous termination of ventricular fibrillation (VF). Therefore, we hypothesized that a spatiotemporally controlled defibrillation (STCD) strategy using defibrillation shocks preceded by Sync P can improve defibrillation efficacy. Method and Results: We explored the STCD effects in 13 isolated rabbit hearts. During VF, a low‐voltage gradient (LVG) area was synchronized by Sync P for 0.92 second. For Sync P, optical action potentials (OAPs) adjacent to four pacing electrodes (10 mm apart) were monitored. When one of the electrodes was in the excitable gap, a 5‐mA current was administered from all electrodes. A shock was delivered 23 ms after the excitable gap when the LVG area was unexcitable. The effects of STCD was compared to random shocks (C) by evaluating the defibrillation threshold 50% (DFT50; n = 35 for each) and preshock coupling intervals (n = 208 for STCD, n = 172 for C). Results were as follows. (1) Sync P caused wavefront synchronization as indicated by a decreased number of phase singularity points (P < 0.0001) and reduced spatial dispersion of VF cycle length (P < 0.01). (2) STCD decreased DFT50 by 10.3% (P < 0.05). (3) The successful shocks showed shorter preshock coupling intervals (CI; P < 0.05) and a higher proportion of unexcitable shock at the LVG area (P < 0.001) than failed shocks. STCD showed shorter CIs (P < 0.05) and a higher unexcitable shock rate at LVG area (P < 0.05) than C. Conclusion: STCD improves defibrillation efficacy by synchronizing VF activations and increasing probability of shock delivery to the unexcitable LVG area. (J Cardiovasc Electrophysiol, Vol. 15, pp. 581‐587, May 2004)
Sotalol Reverses Remodeled Action Potential in Patients with Chronic Atrial Fibrillation but Does Not Prevent Arrhythmia Recurrence
Authors: OSAKA TOSHIYUKI , YAMAZAKI MASATOSHI , YOKOYAMA ERIKO , ITO ATSUSHI , KODAMA ITSUO 
Published: August 2010

Introduction: Recurrence of atrial fibrillation (AF) may be related to AF‐induced electrical remodeling characterized by shortening of the atrial action potential duration (APD) and loss of its rate adaptation. We investigated the effects of pretreatment with oral d,l‐sotalol on rate‐dependent changes in atrial monophasic action potential (MAP) duration after cardioversion of chronic AF with reference to the efficacy in preventing the arrhythmia recurrence. Methods and Results: MAPs were recorded from the right atrium at six pacing cycle lengths (CLs) from 300 to 750 ms in 19 chronic AF patients after electrical cardioversion; 9 had been pretreated with oral d,l‐sotalol (196 ± 42 mg/day) for 7 days and 10 were untreated. MAP duration at 90% repolarization (MAPD90) in 11 control patients increased progressively with increases in CLs from 209 ± 19 ms at CL = 300 ms to 264 ± 28 ms at CL = 750 ms. In AF patients without sotalol, the CL‐MAPD relation was shifted downward and flattened at longer CLs; MAPD90 values were 206 ± 11 ms and 227 ± 16 ms at CLs of 300 and 750 ms, respectively. MAPD90 values at CLs ≥500 ms in AF were significantly shorter than controls. In AF patients with sotalol, the normal CL‐MAPD relation was preserved; MAPD90 increased from 226 ± 19 ms to 282 ± 46 ms in the CL range. AF recurred within 2 weeks after cardioversion in 14 of 24 patients pretreated with d,l‐sotalol (216 ± 51 mg/day) despite of continuation of sotalol treatment. Conclusion: Sotalol reverses AF‐induced decrease in MAPD adaptation to rate in the atria of chronic AF patients, but this effect does not lead to prevention of AF recurrence.
Relationships Between Depolarization Abnormality and Repolarization Abnormality in Patients with Brugada Syndrome:
Authors: HISAMATSU KENICHI , KUSANO KENGO FUKUSHIMA , MORITA HIROSHI , TAKENAKA SHIHO , NAGASE SATOSHI , NAKAMURA KAZUFUMI , EMORI TETSURO , MATSUBARA HIROMI , MIKOUCHI HIROSHI , NISHIZAKI YOSHITOMO , OHE TOHRU 
Published: August 2010

Introduction: Repolarization and depolarization abnormalities have been reported to be related to Brugada syndrome. Methods and Results: We evaluated the relationships between repolarization abnormality and depolarization abnormality using 48‐lead unipolar signal‐averaged electrocardiograms and 87‐lead unipolar body surface maps in 15 patients with Brugada‐type ECGs. Data were compared with those from healthy control subjects (n = 5) and within subgroups of Brugada syndrome with (n = 8) and without (n = 7) ventricular arrhythmias (VA) induced by programmed electrical stimulation (PES). Eighty‐seven‐lead body surface maps were recorded, and potential maps were constructed to evaluate elevation of the ST segment 20 ms after the J point. Forty‐eight‐lead signal‐averaged ECGs were recorded, and isochronal maps of duration of the delayed potential (dDP) were constructed to evaluate the dDP in each lead. Potential maps showed that patients with Brugada‐type ECG, especially those with VA induced by programmed electrical stimulation, had greater elevation of the ST segment in the right ventricular outflow tract, especially at E5. Isochronal maps of dDP in the Brugada‐type ECG group showed that maximum dDP was located at E5 and that the area with long dDP was larger than that in the control subjects. The dDPs at E7, E5, F7, and F5 in the VA‐inducible group were significantly longer than those in the VA‐noninducible group. These results showed that the location of greater elevation in the ST segment coincided with the location of longer dDP. Conclusion: Repolarization abnormality and depolarization abnormality in the walls of both ventricles, especially in the right ventricular outflow tract, are related to the VA of Brugada syndrome.
Canine Model of Brugada Syndrome Using Regional Epicardial Cooling of the Right Ventricular Outflow Tract
Authors: NISHIDA KUNIHIRO , FUJIKI AKIRA , MIZUMAKI KOICHI , SAKABE MASAO , SUGAO MASATAKA , TSUNEDA TAKAYUKI , INOUE HIROSHI 
Published: August 2010

Introduction: Myocardial cooling can induce J point elevation (Osborn wave) as seen on ECG of the Brugada syndrome by activating transient outward current (Ito) and causing a spike‐and‐dome configuration of the monophasic action potential (MAP) in the ventricular epicardium in isolated canine ventricular wedge preparations. We determined the effect of regional epicardial cooling of the right ventricular outflow tract (RVOT) on surface ECG and ventricular vulnerability in the dog. Methods and Results: In 12 dogs, a cooling device (20‐mm diameter) was attached to the RVOT epicardium, and surface ECG, epicardial MAP, and endocardial MAP were recorded. Regional cooling (29.7°C ± 2.2°C) elevated the J point from 0.05 ± 0.06 mV to 0.12 ± 0.11 mV and induced T wave inversion (from 0.02 ± 0.12 mV to −0.27 ± 0.20 mV) in lead V1 in association with “spike‐and‐dome” configuration of the epicardial MAP. Cooling prolonged MAP duration in the RVOT epicardium from 172 ± 27 ms to 213 ± 30 ms (P < 0.01) but not in the RV endocardium and increased transmural dispersion of MAP duration from 9 ± 8 ms to 44 ± 21 ms (P < 0.01). Cooling also prolonged the QT interval in lead V1 from 191 ± 19 ms to 212 ± 23 ms (P < 0.05), but not in lead V5, and increased spatial dispersion of QT interval from 7 ± 5 ms to 20 ± 10 ms (P < 0.01). QT interval in lead V1 correlated positively with MAP duration in the RVOT epicardium (r = 0.75). T wave amplitude in lead V1 correlated inversely with transmural dispersion of MAP duration in the RVOT (r =−0.74). Vagal nerve stimulation accentuated the cooling‐induced changes. During cooling, ventricular fibrillation was induced by a single extrastimulus in 2 of 4 dogs, and additional vagal nerve stimulation during isoproterenol administration induced spontaneous ventricular fibrillation in one dog. Conclusion: Localized epicardial cooling of the RVOT could be an in vivo experimental model of Brugada syndrome. (J Cardiovasc Electrophysiol, Vol. 15, pp. 936‐941, August 2004)
Biventricular Implantable Cardioverter Defibrillators Improve Survival Compared with Biventricular Pacing Alone in Patients with Severe Left Ventricular Dysfunction
Authors: ERMIS CENGIZ , LURIE KEITH G. , ZHU ALAN X. , COLLINS JOANNE , VANHEEL LAURA , SAKAGUCHI SCOTT , LU FEI , PHAM SCOTT , BENDITT DAVID G. 
Published: August 2010

Introduction: Biventricular cardiac pacemakers provide important hemodynamic benefit in selected patients with heart failure and severe left ventricular (LV) dysfunction. Nevertheless, these patients remain at high mortality risk. To address this issue, we examined mortality outcome in patients with heart failure treated with biventricular pacemakers alone and those treated with biventricular implantable cardioverter defibrillators (ICDs). Methods and Results: The study population consisted of 126 consecutive patients with LV dysfunction and heart failure who received either a biventricular ICD (n = 62) or a biventricular pacemaker (n = 64) between January 1998 and December 2002. A minimum 12 months of follow‐up was obtained in all survivors. ICD indications were conventional in all patients. Kaplan‐Meier actuarial method and log rank statistics were used to calculate and compare survival rates in both groups. Comparison of mortality rates utilized Chi‐square test. The two groups had similar clinical and demographic features, LV ejection fraction, and medication use. Average follow‐up times were 13 ± 11.8 months (range 4–60) and 18 ± 13.2 months (range 0.5–53) for biventricular ICD and pacemaker groups, respectively. Overall mortality rate was significantly lower in the biventricular ICD group (13%, 8 deaths) compared to the pacemaker group (41%, 26 deaths) (P = 0.01). Further, the predominant survival benefit for ICD‐treated patients becomes evident after the first 12 months of follow‐up. Conclusion: The findings in this study, although necessarily limited in their interpretation by the absence of treatment randomization, suggest that biventricular ICDs offer a survival benefit compared to biventricular pacing alone. Furthermore, this benefit may be most apparent if other clinical factors do not preclude patient survival >1 year postimplant.
Prevalence of Asymptomatic Recurrences of Atrial Fibrillation After Successful Radiofrequency Catheter Ablation
Authors: ORAL HAKAN , VEERAREDDY SRIKAR , GOOD ERIC , HALL BURR , CHEUNG PETER , TAMIRISA KAMALA , HAN JIHN , FORTINO JACKIE , CHUGH AMAN , BOGUN FRANK , PELOSI FRANK , MORADY FRED 
Published: August 2010

Introduction: The long‐term efficacy of radiofrequency catheter ablation of atrial fibrillation (AF) has been based on patient‐reported symptoms suggestive of AF. However, asymptomatic recurrences of AF may remain undetected. The aim of this study was to determine the prevalence of asymptomatic recurrences of AF after an apparently successful catheter ablation procedure for AF. Methods and Results: Among 244 consecutive patients (mean age 53 ± 11 years) who underwent a pulmonary vein isolation procedure for symptomatic paroxysmal AF and who reported no symptoms of recurrent AF at ≥6 months after the procedure, 60 patients with a history of ≥1 episode of AF per week were asked to participate in this study. Preablation, these patients had experienced 19 ± 13 episodes of AF per month. The patients were provided with a patient‐activated transtelephonic event recorder for 30 days, a mean of 642 ± 195 days after the ablation procedure, and were asked to record and transmit recordings on a daily basis and whenever they felt palpitations. Seven patients (12%) felt palpitations during the study, although they had not experienced symptoms previously. Each of these 7 patients had an episode of AF documented with the event monitor during symptoms. In these 7 patients, the mean number of episodes per month decreased from 19 ± 14 preablation to 3 ± 1 postablation (P < 0.001). Among the 53 asymptomatic patients, an episode of AF was captured in 1 (2%) patient during the study period. Conclusion: Asymptomatic recurrences of AF after an apparently successful catheter ablation procedure for symptomatic paroxysmal AF are infrequent.