bluuebunny/crossref_metadata_2025 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)
Structural Pathways and Prevention of Heart Failure and Sudden Death
Authors: Pacifico Antonio , Henry Philip D.
Published: August 2010

We review the macroscopic and microscopic anatomy of myocardial disease associated with heart failure (HF) and sudden cardiac death (SCD) and focus on the prevention of SCD in light of its structural pathways. Compared to patients without SCD, patients with SCD exhibit 5‐ to 6‐fold increases in the risks of ventricular arrhythmias and SCD. Epidemiologically, left ventricular hypertrophy by ECG or echocardiography acts as a potent dose‐dependent SCD predictor. Dyslipidemia, a coronary disease risk factor, independently predicts echocardiographic hypertrophy. In adult SCD autopsy studies, increases in heart weight and severe coronary disease are constant findings, whereas rates of acute coronary thrombi vary remarkably. The microscopic myocardial anatomy of SCD is incompletely defined but may include prevalent changes of advanced myocardial disease, including cardiomyocyte hypertrophy, cardiomyocyte apoptosis, fibroblast hyperplasia, diffuse and focal matrix protein accumulation, and recruitment of inflammatory cells. Hypertrophied cardiomyocytes express “fetospecific” genetic programs that can account for acquired long QT physiology with risk for polymorphic ventricular arrhythmias. Structural heart disease associated with HF and high SCD risk is causally related to an up‐regulation of the adrenergic renin‐angiotensin‐aldosterone pathway. In outcome trials, suppression of this pathway with combinations of beta‐blockers, angiotensin‐converting enzyme inhibitors, angiotensin‐II receptor blockers, and mineralocorticoid receptor blockers have achieved substantial total mortality and SCD reductions. Contrarily, trials with ion channel‐active agents that are not known to reduce structural heart disease have failed to reduce these risks. Device therapy effectively prevents SCD, but whether biventricular pacing‐induced remodeling decreases left ventricular mass remains uncertain. (J Cardiovasc Electrophysiol, Vol. 14, pp. 764‐775, 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)
Case of Polymorphic Ventricular Tachycardia in Diphenhydramine Poisoning
Authors: JOSHI AJAY K. , SLJAPIC TATJANA , BORGHEI HASSAN , KOWEY PETER R.
Published: August 2010

This is the first reported case of torsades de pointes attributable to diphenhydramine, a drug with weak IKreffects. A 26‐year‐old, healthy man was admitted to intensive care after a diphenhydramine overdose. Results of physical examination, ECG, and electrolytes were normal at admission. Despite supportive care, he developed typical, sustained, torsades de pointes with a markedly prolonged QT interval requiring cardioversion. Drugs with weak IKr‐blocking effects may cause lethal proarrhythmia in susceptible individuals when delivered in high concentrations. This case illustrates the variation in repolarization reserve that exists in a free‐standing population.(J Cardiovasc Electrophysiol, Vol. 15, pp. 591‐593, May 2004)
Potassium Channels and Membrane Potential in the Modulation of Intracellular Calcium in Vascular Endothelial Cells
Authors: ADAMS DAVID J. , HILL MICHAEL A.
Published: August 2010

The endothelium plays a vital role in the control of vascular functions, including modulation of tone; permeability and barrier properties; platelet adhesion and aggregation; and secretion of paracrine factors. Critical signaling events in many of these functions involve an increase in intracellular free Ca2+concentration ([Ca2+]i). This rise in [Ca2+]ioccurs via an interplay between several mechanisms, including release from intracellular stores, entry from the extracellular space through store depletion and second messenger‐mediated processes, and the establishment of a favorable electrochemical gradient. The focus of this review centers on the role of potassium channels and membrane potential in the creation of a favorable electrochemical gradient for Ca2+entry. In addition, evidence is examined for the existence of various classes of potassium channels and the possible influence of regional variation in expression and experimental conditions.(J Cardiovasc Electrophysiol, Vol. 15, pp. 598‐610, May 2004)
Electrical Disconnection of the Coronary Sinus by Radiofrequency Catheter Ablation to Isolate a Trigger of Atrial Fibrillation
Authors: SANDERS PRASHANTHAN , JAÏS PIERRE , HOCINI MÉLÈZE , HAÏSSAGUERRE MICHEL
Published: August 2010

We report a case of radiofrequency catheter ablation for chronic atrial fibrillation, in which electrical disconnection of the coronary sinus was necessary to isolate a trigger initiating atrial fibrillation. (J Cardiovasc Electrophysiol, Vol. 15, pp. 364‐368, 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)
Utility of Implantable Cardioverter Defibrillator Electrograms to Estimate Repolarization Alternans Preceding a Tachyarrhythmic Event
Authors: ARMOUNDAS ANTONIS A. , ALBERT CHRISTINE M. , COHEN RICHARD J , MELA THEOFANIE ,   TOVA INVESTIGATORS
Published: August 2010

Electrical alternans is a pattern of variation in the shape of the ECG waveform that appears on an every‐other‐beat basis. In humans, alternation in ventricular repolarization, namely, repolarization alternans, has been associated with increased vulnerability to ventricular tachycardia/ventricular fibrillation and sudden cardiac death. This study investigates the utility of implantable cardioverter defibrillator electrograms to estimate repolarization alternans preceding a tachyarrhythmic event. It is demonstrated that microvolt‐level repolarization alternans is present prior to an arrhythmic event, and one can record low‐amplitude‐noise signals that can be used to obtain reliable estimates of repolarization alternans. This study eventually may lead to new methods that would prevent the onset of malignant tachyarrhythmias. (J Cardiovasc Electrophysiol, Vol. 15, pp. 594‐597, May 2004)
Parasympathetic Cardiac Nerve Stimulation with Implanted Coronary Sinus Lead
Authors: VÁGÓ HAJNALKA , RÓKA ATTILA , ACSÁDY GYÖRGY , MERKELY BÉLA
Published: August 2010

A patient with drug‐refractory paroxysmal atrial fibrillation associated with rapid ventricular rate underwent biatrial pacemaker implantation. During elective replacement of the pacemaker, a significant voltage‐ and frequency‐dependent decrease in ventricular rate was achieved by high‐frequency electrical stimulation (17 Hz) of parasympathetic cardiac nerves innervating the AV node with the implanted bipolar coronary sinus electrode. The negative dromotropic effect of parasympathetic stimulation was eliminated by intravenous administration of 1‐mg atropine. (J Cardiovasc Electrophysiol, Vol. 15, pp. 588‐590, 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)
Death Due to an Implantable Cardioverter Defibrillator
Authors: MESSALI ANNE , THOMAS OLIVIER , CHAUVIN MICHEL , COUMEL PHILIPPE , LEENHARDT ANTOINE
Published: August 2010

Inappropriate therapy due to noise oversensing caused a true ventricular fibrillation (VF) and death of a patient. A 49‐year‐old patient with a history of dilated cardiomyopathy received a double‐chamber implantable cardioverter defibrillator (ICD) in 1991 for a sustained inducible ventricular tachycardia (VT). One appropriate shock delivered in 1994 terminated an episode of VT. The generator was replaced in 1995 and in 2000, and was connected to the initial leads. Three months after the second replacement, the patient received six consecutive shocks related to detection of noise interpreted as VF. Unfortunately, the sixth shock triggered a true VF, which was not treated due to end of the therapeutic sequence, and the patient died. The causes of the dysfunction are discussed.
Necessity for Biatrial Ablation to Achieve Bidirectional Cavotricuspid Isthmus Conduction Block in a Patient Following Senning Operation
Authors: DONG JUN , ZRENNER BERNHARD , SCHREIECK JÜRGEN , SCHMITT CLAUS
Published: August 2010

We report the case of a 28‐year‐old male patient with a 17‐year history of recurrent symptomatic atrial tachyarrhythmia following Senning operation for transposition of the great arteries. Biatrial electroanatomic mapping and entrainment mapping revealed counterclockwise peri‐tricuspid annulus reentry in which cavotricuspid isthmus tissue in both systemic and pulmonary venous atria was involved. Linear ablation of the cavotricuspid isthmus in the pulmonary venous atrium terminated the tachycardia but did not block the isthmus conduction, and the tachycardia was reinduced. Bidirectional isthmus conduction block could be achieved only after additional linear ablation targeting the cavotricuspid isthmus tissue in the systemic venous atrium. We conclude that biatrial ablation may be necessary in order to achieve bidirectional isthmus block and prevent tachycardia recurrence in some patients following Senning or Mustard operation.
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.
Left Atrial–Esophageal Fistula Following Radiofrequency Catheter Ablation of Atrial Fibrillation
Authors: SCANAVACCA MAURICIO I. , D'ÁVILA ANDRÉ , PARGA JOSÉ , SOSA EDUARDO
Published: August 2010

This report describes a fatal case of left atrial‐esophageal fistula occurring in a 72‐year‐old man after a radiofrequency catheter ablation of paroxysmal atrial fibrillation. Catheter ablation was performed around the pulmonary vein using an 8‐mm‐tip electrode (60 W or 55°C) guided by a 25‐mm circular catheter. On day 22 of follow‐up, the patient presented with seizures followed by hematemesis due to left atrial–esophageal fistula. His clinical condition deteriorated, and he died of speticemia. Thus, left atrial–esophageal fistula is a sever complication of radiofrequency catheter ablation of the left atrial posterior wall. (J Cardiovasc Electrophysiol, Vol. 15, pp. 960‐962, August 2004)
Effects of Psychologic Stress on Repolarization and Relationship to Autonomic and Hemodynamic Factors
Authors: LAMPERT RACHEL , SHUSTERMAN VLADIMIR , BURG MATTHEW M. , LEE FORRESTER A. , EARLEY CHRISTINE , GOLDBERG ANNA , MCPHERSON CRAIG A. , BATSFORD WILLIAM P. , SOUFER ROBERT
Published: August 2010

Introduction: Psychological stress can precipitate ventricular arrhythmias in patients with ICDs, as well as sudden death. However, the physiologic pathways remain unknown. We sought to determine whether psychological stress induced in the laboratory setting alters indices of repolarization associated with arrhythmogenesis.

Methods and Results: Patients with ICDs and a history of ventricular arrhythmia underwent ambulatory ECG monitoring during a laboratory mental stress protocol (anger recall and mental arithmetic). Continuous changes in repolarization indices which have correlated with temporal and spatial myocardial heterogeneity of repolarization, including T‐wave alternans (TWA), T‐wave amplitude (Tamp), and T‐wave area (Tarea) were analyzed in the time domain. In the 33 patients (85% male, 88% with coronary artery disease, mean ejection fraction 30%), norepinephrine, epinephrine, BP, and HR increased during mental stress. TWA increased from 22 (interquartile range 16–27) at baseline to 29 (21–38) uV during mental stress (P < 0.001). Changes in TWA correlated with changes in HR, systolic BP, and catecholamines. Tamp and Tarea also increased with mental stress (P < 0.01) but did not correlate with changes in other variables.

Conclusion: Psychological stress increased TWA, Tamp, and Tarea. Autonomically mediated repolarization changes may be a pathophysiologic link between emotion and arrhythmia in susceptible patients.
Role of Streptomycin‐Sensitive Stretch‐Activated Channel in Chest Wall Impact Induced Sudden Death (Commotio Cordis)
Authors: GARAN ARTHUR R. , MARON BARRY J. , WANG PAUL J. , ESTES N. A. MARK , LINK MARK S.
Published: August 2010

Introduction: Deaths secondary to low‐energy impacts to the precordium in young individuals (commotio cordis) have been reported with increasing frequency. In a swine model, baseball impacts induce ventricular fibrillation when directed at the center of the left ventricle during the vulnerable portion of repolarization just prior to the T‐wave peak. It has been hypothesized that activation of stretch‐sensitive channels could be crucial for this electrophysiological phenomenon. In this study, a nonselective stretch‐activated cation channel was pharmacologically blocked prior to chest blows to determine whether this channel represents a possible pathway by which commotio cordis events occur.

Methods: In a randomized and blinded experiment, 12 swine (mean 17.1 ± 2.5 kg) received either 2‐g streptomycin intramuscularly (mean serum concentration 115 ± 18 μM) or sterile water prior to chest impact. Each animal received six precordial impacts with a baseball propelled at 40 mph.

Results: There was no significant difference in the frequency of induced VF in the animals administered streptomycin (10 of 19 impacts: 53%) compared to those control animals receiving only sterile water (10 of 31: 32%) (P = 0.15). However, the magnitude of ST segment elevation was less in the streptomycin‐treated animals (19 ± 19 mV) versus controls (61 ± 46 mV) (P = 0.015).

Conclusion: Streptomycin did not alter the frequency of ventricular fibrillation in our commotio cordis model, indicating that the stretch‐activated channel is not implicated in the genesis of chest blow‐induced cardiac arrest. However, streptomycin did reduce ST elevation following impact suggesting that the stretch‐activated channel may play a role in ST segment elevation following chest wall blows.
The Clinical Implications of Cumulative Right Ventricular Pacing in the Multicenter Automatic Defibrillator Trial II
Authors: STEINBERG JONATHAN S. , FISCHER AVI , WANG PAUL , SCHUGER CLAUDIO , DAUBERT JAMES , MCNITT SCOTT , ANDREWS MARK , BROWN MARY , HALL W. JACKSON , ZAREBA WOJCIECH , MOSS ARTHUR J. ,   MADIT II Investigators
Published: August 2010

Introduction:This study was designed to assess whether right ventricular pacing in the implantable cardioverter defibrillator (ICD) arm of the Multicenter Automatic Defibrillator Implantation Trial (MADIT) II was associated with an unfavorable outcome.

Methods and Results:Data on the number of ventricular paced beats were available in 567 (76%) of 742 MADIT II patients with ICDs. The number of ventricular paced beats over the total number of beats showed a bimodal distribution with patients being predominantly paced or nonpaced. Therefore, patients were dichotomized at 0–50% and 51–100% of cumulative pacing with median pacing rate 0.2% and 95.6%, respectively. Endpoints included new or worsening heart failure, appropriate ICD therapy for VT/VF, and the combined endpoint of heart failure or death. Clinical features associated with frequent ventricular pacing included age ≥65 years, advanced NYHA heart failure class, LVEF < 0.25, first degree AV and bundle branch block, and amiodarone use. During follow‐up, 119 patients (21%) had new or worsened heart failure, 130 (23%) had new or worsened heart failure or death, and 142 (25%) had appropriate therapy for VT/VF. In comparison to patients with infrequent pacing, those with frequent pacing had significantly higher risk of new or worsened heart failure (hazard ratio = 1.93; P = 0.002) and VT/VF requiring ICD therapy (HR = 1.50; P = 0.02).

Conclusions:Patients in MADIT II who were predominantly paced had a higher rate of new or worsened heart failure and were more likely to receive therapy for VT/VF. These results suggest the deleterious consequences of RV pacing, particularly in the setting of severe LV dysfunction.
De la contention
Authors: Philippe Julien
Published: August 2010

La contention temporaire a pour but d’empêcher une cause de récidive de produire ses
effets : elle fait obstacle aux réactions ligamentaires consécutives aux déplacements des
dents. Elle ne peut rien pour les autres causes de récidive qui doivent être détectées et
supprimées en dehors de la contention, dans le cadre du traitement. Pour être efficace,
cette contention doit être immédiate, complète et prolongée. Les dispositifs les plus
utilisés sont la plaque de Hawley, les gouttières transparentes et les fils collés. Aucun
n’est parfait. Seule la contention permanente assure la stabilité des résultats du
traitement quelles que soient les causes de récidive. Les risques en sont encore mal
connus.
Conséquences esthétiques du traitement de la classe II : étude
comparative Distal Active Concept (DAC)/Forces Extra-Buccales (FEB)
Authors: Dénarié Sophia , Gebeile-Chauty Sarah , Aknin Jean-Jacques
Published: August 2010

Les thérapeutiques orthodontiques fréquemment utilisées dans le passé tendaient à
corriger les malocclusions de classe II en freinant la croissance squelettique par
l’utilisation de tractions extra-orales ; la démarche actuelle réduit l’emploi de
tractions sur le maxillaire et s’oriente vers une stimulation de la croissance
mandibulaire. Cette différence d’approche thérapeutique se répercute-t-elle sur
l’esthétique faciale ? Pour évaluer les conséquences esthétiques sur le profil, nous avons
réalisé une étude portant sur 64 patients en denture adolescente présentant une
malocclusion de classe II, division 1 n’ayant subi aucune extraction et aucun traitement
orthodontique préalable. Deux groupes d’adolescents ont été différenciés : l’un de 33
patients traités par Distal Active Concept (DAC), l’autre de 31 patients
traités par Forces Extra-Buccales (FEB) sur multi-attache. Nous avons comparé, par des
mesures céphalométriques, les profils obtenus après les deux types de traitements. Les
résultats obtenus au niveau des tissus cutanés de l’étage inférieur de la face montrent un
développement sagittal cutané significativement plus important pour le groupe d’enfants
traité par DAC.
La genèse de la supraclusion
Authors: Bocquet Emmanuelle , Moreau Alexis , Decrucq Edouard , Djerbi Narimen , Danguy-Derot Chantale , Danguy Michel
Published: August 2010

La supraclusion incisive est un signe clinique présent chez beaucoup de patients traités
en orthodontie. Elle est difficile à corriger et récidive fréquemment. Afin de la traiter
avec la thérapeutique la plus appropriée, il est nécessaire de connaître de façon précise
ses étiologies, qui peuvent être basales, neuromusculaires ou dentaires avec une
intrication souvent complexe. Cette complexité est retrouvée dans les mécanismes
d’installation et donc dans l’élaboration du diagnostic qui sera basé sur une analyse
céphalométrique architecturale de l’organe de préhension.
Ever-Greening: A Status Check in Selected Countries
Authors: Rathod Sandeep Kanak
Published: August 2010

Evergreening or extension of drug life through various product life cycle management tactics is an issue that significantly affects the generic pharmaceutical sector. Evergreening results in delayed market access for generic companies as well as higher drug prices in market for a longer duration. Both of these results are detrimental to patients. This article looks at evergreening practices seen in various countries across the develop ment index. It covers diverse countries on the development spectrum, ranging from countries like Canada and Australia to countries like India, Philippines and Thailand. It highlights the response that Governments and generic companies are taking to regulate and to counter ever-greening practices. The types of evergreening practices noted are follow-on or secondary patents, aggressive litigation practices, and finally patent mechanisms being linked with regulatory approval (linkage) introduced via Free Trade Agreements.
Thermal conductivity of pure silica MEL and MFI zeolite thin films
Authors: Coquil Thomas , Lew Christopher M. , Yan Yushan , Pilon Laurent
Published: August 2010

This paper reports the room temperature cross-plane thermal conductivity of pure silica zeolite (PSZ) MEL and MFI thin films. PSZ MEL thin films were prepared by spin coating a suspension of MEL nanoparticles in 1-butanol solution onto silicon substrates followed by calcination and vapor-phase silylation with trimethylchlorosilane. The mass fraction of nanoparticles within the suspension varied from 16% to 55%. This was achieved by varying the crystallization time of the suspension. The thin films consisted of crystalline MEL nanoparticles embedded in a nonuniform and highly porous silica matrix. They featured porosity, relative crystallinity, and MEL nanoparticles size ranging from 40% to 59%, 23% to 47% and 55 nm to 80 nm, respectively. PSZ MFI thin films were made by in situ crystallization, were b-oriented, fully crystalline, and had a 33% porosity. Thermal conductivity of these PSZ thin films was measured at room temperature using the 3ω method. The cross-plane thermal conductivity of the MEL thin films remained nearly unchanged around 1.02±0.10 W m−1 K−1 despite increases in (i) relative crystallinity, (ii) MEL nanoparticle size, and (iii) yield caused by longer nanoparticle crystallization time. Indeed, the effects of these parameters on the thermal conductivity were compensated by the simultaneous increase in porosity. PSZ MFI thin films were found to have similar thermal conductivity as MEL thin films even though they had smaller porosity. Finally, the average thermal conductivity of the PSZ films was three to five times larger than that reported for amorphous sol-gel mesoporous silica thin films with similar porosity and dielectric constant.
Critical Casimir effect for colloids close to chemically patterned substrates
Authors: Tröndle M. , Kondrat S. , Gambassi A. , Harnau L. , Dietrich S.
Published: August 2010

Colloids immersed in a critical or near-critical binary liquid mixture and close to a chemically patterned substrate are subject to normal and lateral critical Casimir forces of dominating strength. For a single colloid, we calculate these attractive or repulsive forces and the corresponding critical Casimir potentials within mean-field theory. Within this approach we also discuss the quality of the Derjaguin approximation and apply it to Monte Carlo simulation data available for the system under study. We find that the range of validity of the Derjaguin approximation is rather large and that it fails only for surface structures which are very small compared to the geometric mean of the size of the colloid and its distance from the substrate. For certain chemical structures of the substrate, the critical Casimir force acting on the colloid can change sign as a function of the distance between the particle and the substrate; this provides a mechanism for stable levitation at a certain distance which can be strongly tuned by temperature, i.e., with a sensitivity of more than 200nm∕K.
Finite-temperature infrared spectroscopy of polycyclic aromatic hydrocarbon molecules. II. Principal mode analysis and self-consistent phonons
Authors: Calvo F. , Parneix P. , Van-Oanh N.-T.
Published: August 2010

Following previous work [F. Calvo et al. J. Chem. Phys. 132, 124308 (2010)], infrared spectra of several polycyclic aromatic hydrocarbon molecules are simulated with classical and quantum molecular dynamics trajectories. The interactions are modeled using a tight-binding potential energy surface and quantum delocalization is accounted for using the partially adiabatic centroid and ring-polymer molecular dynamics frameworks, both built upon the path-integral representation. The spectra obtained directly by Fourier transformation of the dipole moment autocorrelation function are here compared with several quasiharmonic approximations that provide additional information about the vibrational modes. A principal mode analysis (PMA) is carried out from the covariance matrix of atomic displacements in classical and quantum trajectories. The method systematically overestimates the line shifts due to anharmonicities, except in the power spectra of atomic displacements, and is not robust in predicting IR intensities for such large molecules. Alternatively, effective normal modes have also been determined by adapting the self-consistent phonon (SCP) theory of condensed matter physics to the present tight-binding model, in both classical and quantum mechanical descriptions. The SCP approximation turns out as semiquantitative in estimating the redshift of tight stretching modes, and performs better for classical systems. More problematic, it predicts that many low- or medium-frequency modes should be blueshifted, in contradiction with the molecular dynamics results. The sets of anharmonic normal modes extracted from the PMA and SCP approaches reveal important mixings within the tightest C–H and C–C stretching modes, which are also manifested on the corresponding power spectra.